Practical Handbook for Small-Gauge Vitrectomy: A Step-by-Step Introduction to Surgical Techniques

Practical Handbook for Small-Gauge Vitrectomy

Ulrich Spandau • Heinrich Heimann

Practical Handbook for Small-Gauge Vitrectomy A Step-By-Step Introduction to Surgical Techniques

Authors Ulrich Spandau, M.D., Ph.D. Department of Ophthalmology Uppsala University Hospital Uppsala Sweden [email protected]

Prof. Dr. med. Heinrich Heimann, M.D. St. Paul's Eye Unit Royal Liverpool University Hospital Liverpool, Merseyside UK [email protected]

ISBN 978-3-642-23293-0 e-ISBN 978-3-642-23294-7 DOI 10.1007/978-3-642-23294-7 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2011941508 © Springer-Verlag Berlin Heidelberg 2012 Authorized translation of the 1st German language edition Spandau HH, 23G-Vitrectomie © 2009 by Kaden-Verlag, Heidelberg This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

This book is dedicated to my teacher Zoran Tomic, who inspired me for retinal surgery. He is a pioneer in the development of bimanual surgery and in particular the bimanual removal of membranes. It is he, who should have written this book. Ulrich Spandau

Foreword 1 (German Edition)

In 2002 when the team of Eugene de Juan, Los Angeles, published their first experience of the transconjunctival sutureless vitrectomy with 25-gauge instruments, it could not be foreseen that the “small gauge vitrectomy” would become the new standard procedure of vitrectomy within a few years. Most retinal surgeons had previously considered the conjunctiva and sclera in a 20-gauge vitrectomy as a more or less troublesome and time-consuming obstacle before and after their true passion, the vitreous cavity. The extensive opening of the conjunctiva in conventional 20-gauge vitrectomy, the suture material used for the closure of sclera and conjunctiva and the sometimes wide-scale application of diathermy resulted often in a pronounced trauma of the outer layers of the eye. Thus, any revisional surgery became increasingly difficult due to the increased scarring of conjunctiva and Tenon’s capsule and the atrophy of the sclera in the pars plana. Due to their flexibility, the first 25-gauge instruments were initially only used for relatively simple vitreoretinal surgery at the posterior pole. However, the minimally invasive approach by de Juan was from the beginning fascinating, because not only was the extraocular part of a vitrectomy significantly shortened, but the trauma of conjunctiva and sclera were also significantly reduced. In 2004, inspired by de Juan’s method, Claus Eckardt developed a trocar cannula system and instruments with a diameter of 23-gauge in Frankfurt-Höchst. This invention had on one side the advantage of the 25-gauge vitrectomy and on the other side the efficiency of the 20-gauge instruments. The aim was to carry out all possible vitreoretinal surgery with the same instrumentarium, and this has since then become reality in our department. A key to the success of the 23-gauge technology step has been Claus Eckardt’s concept of a tangential insertion of the trocars and the use of valves for the cannulas: Due to the tunnel-shaped incision technique within the sclera, an intraoperatively stable positioning of the cannulas and a sutureless closure of the sclerotomies after removal of the cannulas, postoperative hypotension or even endophthalmitis could be prevented. The valves allow a vitrectomy in a closed system and reduce the flow of infusion fluid through the vitreous cavity. Ulrich Spandau presents in this very practical book on 23-gauge vitrectomy the latest equipment and instruments needed for a 23-gauge vitrectomy and he explains in detail the most important surgical techniques.

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Foreword 1 (German Edition)

A lot of useful tips, and last but not least the included DVD with a variety of surgical videos, make this book a very useful surgical compendium. This practical book will be a great guide for young ophthalmic surgeons who want to familiarize themselves with modern vitrectomy. Even experienced vitreoretinal surgeons, who wish to switch from 20-gauge to 23-gauge vitrectomy, will benefit from this compendium. Frankfurt-Höchst, Germany

Tillmann Eckert

Foreword 2

Dr. Ulrich Spandau confirms with this compendium to be the most dedicated of my so far eight fellows in vitreoretinal surgery. He presents here our current surgical concept, instrumentation and operative techniques that have been developed in Uppsala in the last 17 years. It is a transconjunctival, 23-gauge Microincision Vitrectomy Surgery (MIVS), combined with phaco-emulsification in elderly patients, performed bimanually for the most of complex indications. To the best of my knowledge no comparable practical guide for current vitreoretinal surgery has been published since Zivojnovic’s Silicone Oil in Vitreoretinal Surgery, in 1987. Since then vitreoretinal surgery has changed very much, from 20-gauge macroincisional vitrectomy with silicone oil tamponade in most of the cases, to 23-gauge microincisional, bimanual vitrectomy with gas tamponade that we use today. Dr. Spandau has opened a treasure box that he has filled patiently for several years and presents here some genuine surgical pearls, both those that he has discovered for himself, those that we have discussed together, those that I have shown him and furthermore those that were known since before. That gives an opportunity to both beginners and more experienced vitreoretinal surgeons to improve their practical knowledge and refine their procedures in this field. It is our duty to share all the surgical skills and knowledge with each other in order to provide the best results for our patients. This book is a genuine account of our practical work dedicated to them, which Dr. Spandau has written in collaboration with Dr. Heinrich Heimann. Thank you Ulrich and Heinrich! Dr. Zoran Tomic Chief Vitreoretinal Surgeon Department of Ophthalmology University Hospital Uppsala, Sweden

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Preface

Vitreoretinal surgery is developing rapidly. The new 23-gauge and 25-gauge techniques are transforming vitreoretinal surgery into a much safer and less traumatic surgical procedure. We are convinced that the 23-gauge and 25-gauge vitrectomy will become the gold standard for vitrectomy worldwide. It will be as safe and reliable as phacoemulsification is today. This book is intended to be a hands-on instructive compendium for vitreoretinal surgery, which is more technical and sophisticated than phacosurgery. First we describe the instruments and materials needed for vitreoretinal surgery, after which we describe the most important surgeries. Just like a recipe in a cookbook – first the ingredients and then every surgical step in detail. In the final chapter of the book you will find a lot of useful information regarding the surgical material. The surgical techniques described in the book, however, are not the only possible treatment for the described pathology. They are only recommendations, not guidelines or rules. We wish every reader, may he or she be a beginner or an advanced surgeon, to enjoy reading this book and watching the surgical videos. Included are two DVDs with a huge amount of commented surgical videos. They begin with easy techniques and end with advanced pathologies. Our endeavour is to inspire more people to master this amazing surgical technique. Uppsala, Sweden Liverpool, UK

Ulrich Spandau Heinrich Heimann

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Acknowledgements

The skills of vitreoretinal surgery cannot be gained by reading a book. However, there are many little tricks of the trade that one will not find in standard text books and which will be passed on from the supervisor to the learning surgeon during the training. It was our aim to collect as many of these pearls as possible to be passed on to a broader community of learning surgeons through this book. I was fortunate enough to be trained by and to work with some of the outstanding vitreoretinal surgeons of our time who taught and shared their knowledge with me. I am extremely grateful for giving me the opportunity to learn vitreoretinal surgery, for their patience, their invaluable advice and their generosity in sharing their skills: Michael Foerster (Berlin), Norbert Bornfeld (Essen), Ulrich Kellner (Siegburg), Horst Helbig (Regensburg), David Wong (Hong Kong), Bertil Damato (Liverpool) and Nikos Bechrakis (Innsbruck). Together with my colleagues at the St. Paul’s Eye Unit at the Royal Liverpool University Hospital, I am also extremely lucky to be in a position that involves teaching fellows from all over the planet in vitreoretinal surgery. These highly skilled individuals are and were a sheer delight to work with. I would like to thank them for the great care they have provided for the patients in our department. They are constantly challenging and scrutinizing our techniques, which has helped us to further develop the techniques of vitreoretinal surgery: Ron Das (Malaysia), Ben Fleming (Australia), Christina Irigoyen (Spain), Stathis Liazos (Greece), Lazaros Konstandtinidis (Greece), Joaquin Marticorena (Chile), Haslina Mohd Ali (Malaysia), George Morphis (Greece), Mario Romano (Italy), Teresa Sandinha (Portugal) and Xavier Valldeperas (Spain). Liverpool, UK

Heinrich Heimann

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Acknowledgements

I wish to express my gratitude to Dr. Gangolf Sauder (Stuttgart) who taught me my first steps in vitreoretinal surgery, Prof. Claus Eckardt (Frankfurt-Hoechst) and Dr. Tillmann Eckert (Frankfurt-Hoechst) who generously shared their many practical skills. I also wish to thank Dr. Reinhard Kaden for the constant support and encouragement during the preparation of the initial German version of this book, which is published by Kaden Verlag Heidelberg. Finally, I would also like to thank my colleagues, Dr. Tilmann Eckert (Frankfurt-Hoechst), Dr. Lothar Schneider (Sweden), Prof. Dr. Hans Liesenhoff (Mallorca), Dr. Yaser Biazid (Abu Dhabi) and Mr Brian Turner (Sweden) for their critical review of the manuscript. Uppsala, Sweden

Ulrich Spandau

Abbreviations

C2F6 C3F8 CSTS ERM ICG IOFB IOL IOP PDR PDVR PFCL PPV PRP PVD PVR RRD SCH SF6

Perfluoroethane, gas for retinal tamponade Perfluoropropane, gas for retinal tamponade Kinematic viscosity of a fluid (unit = Stokes, here: centi stokes) Epiretinal membrane Indocyanine green, dye used for macular hole surgery Intraocular foreign body Intraocular lens Intraocular pressure Proliferative diabetic retinopathy Proliferative diabetic vitreoretinopathy Perfluorocarbon Pars plana vitrectomy Panretinal laserphotocoagulation Posterior vitreous detachment Proliferative vitreoretinopathy Rhegmatogenous retinal detachment Suprachoroidal haemorrhage Sulphahexafluoride, gas for retinal tamponade

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Contents

1

2

Introduction to Small-Gauge Vitrectomy . . . . . . . . . . . . . . . . . . . . . . .

1

1.1

History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

1.2

Key Features of ‘Micro-Incision Vitrectomy Surgery (MIVS)’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.1 Sutureless sclerotomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 Trocar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Bimanual Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 3 3 4

Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

2.1

Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.1 Operating Microscope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.2 Binocular Indirect Ophthalmo Microscope (BIOM System) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.3 Vitrectomy Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.4 Laser Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.5 Cryo Console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.6 Light Source. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7 7

Standard Instruments for Pars Plana Vitrectomy . . . . . . . . . . . 2.2.1 Instruments for Macular Surgery . . . . . . . . . . . . . . . . . . . . . 2.2.2 Instruments for Peeling for Diabetic Retinopathy and Traction Retinal Detachment with PVR . . . . . . . . . . . .

9 17

2.3

What Instruments Are Needed for Different Interventions? . . . . .

20

2.4

Gases and Liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.1 Perfluorocarbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.2 Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Expanding Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.4 Light Silicone Oils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.5 Heavy Silicone Oils (Densiron 68® and Oxane Hd®) . . . . .

21 22 23 25 27 28

2.2

7 8 9 9 9

18

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Contents

2.5

3

4

5

6

7

Dyes for Vitreous and Membranes . . . . . . . . . . . . . . . . . . . . . . . 2.5.1 Staining of the Vitreous . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5.2 Staining of Epiretinal Membranes . . . . . . . . . . . . . . . . . . . . 2.5.3 Staining of the Inner Limiting Membrane (ILM) . . . . . . . .

30 30 30 31

General Considerations and Techniques of Pars Plana Vitrectomy . . . . .

33

3.1

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33

3.2

Patient Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

3.3

Recommended Learning Steps for Beginners . . . . . . . . . . . . . . .

35

3.4

Complicated Surgeries for Advanced Surgeons . . . . . . . . . . . . .

35

3.5

Anaesthesia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36

3.6

Combined Surgery: Phaco/IOL and Pars Plana Vitrectomy . .

37

3.7

3-Port or 4-Port Vitrectomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.7.1 Conventional 3-Port 23-Gauge Vitrectomy . . . . . . . . . . . . 3.7.2 Bimanual 4-Port 23-Gauge Vitrectomy . . . . . . . . . . . . . . .

39 40 40

Special Techniques for Pars Plana Vitrectomy . . . . . . . . . . . . . . . . . .

41

4.1

Topography in Vitrectomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

4.2

Pars Plana Vitrectomy Step by Step . . . . . . . . . . . . . . . . . . . . . .

41

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

69

Conventional Vitrectomy with 3-Port Trocar Setup . . . . . . . . . . . . . .

71

5.1

Silicone Oil, Densiron 68® and Oxane Hd® Removal . . . . . . . . .

71

5.2

Vitreous Haemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

80

5.3

Epiretinal Membranes and Macular Holes. . . . . . . . . . . . . . . . .

84

5.4

25-Gauge Macular Peeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

93

Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

95

Bimanual Vitrectomy with 4-Port Trocar System . . . . . . . . . . . . . . . .

97

6.1

98

Insertion of Chandelier Light. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diabetic Retinopathy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 7.1

Easy Proliferative Diabetic Retinopathy . . . . . . . . . . . . . . . . . . . 103

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR) . . . . . 105

Contents

8

9

xix

Dislocated Intracoular Lens (IOL) and Dropped Nucleus . . . . . . . . . 113 8.1

Dislocation of the IOL with Capsular Bag due to Zonulolysis . . . .

113

8.2

Dropped Nucleus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Endophthalmitis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

10

Retinal Detachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 10.1 Detachment Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 10.2 Retinal Detachment Complicated by Proliferative Vitreoretinopathy (PVR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

11

Trauma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 11.1 Penetrating Eye Injury by Metal Intraocular Foreign Bodies (IOFB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 11.2 Suprachoroidal Haemorrhage . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

12

Surgical Pearls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 A.1 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 A.2 Company Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 A.3 Instrument Set for PPV (combined and not combined) . . . . . . . 178 A.4 List of Important Pits & Pearls (P&P) . . . . . . . . . . . . . . . . . . . . 180 Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Introduction to Small-Gauge Vitrectomy

1.1

1

History

Since the 1970s, 20-gauge vitrectomy has evolved as the worldwide standard for vitreoretinal surgery. All instruments have a lumen diameter (inside diameter) of 0.9 mm. For this procedure, the conjunctiva is opened, three sclerotomies are placed and the infusion cannula is sutured to the sclera. In the majority of cases, trocar cannulas are not used and at the end of the surgery, the sclerotomies are sutured. In 2002, Eugene de Juan et al. introduced 25-gauge vitrectomy. The instruments had a lumen diameter of 0.5 mm. Trocars (cannulas) were used for the infusion and the instruments. The trocars were inserted transconjunctivally and transsclerally and remained in place during the entire surgery without the need for suturing them to the sclera. A major advantage of this new technique was the reduced anterior segment trauma during the procedure because the conjunctiva is not opened and the instruments are smaller. One disadvantage was an increased risk for postoperative hypotony due to the absence of sutures. Another disadvantage was that the instruments were very flexible and not all instruments could be produced in such a small diameter. Meanwhile, more rigid instruments were developed that proved to be easier to handle. The 25-gauge technology is particularly popular in the United States. In 2004, 23-gauge vitrectomy with a lumen diameter of 0.65 mm was developed at the Eye Clinic Frankfurt- Höchst by Prof. Dr. Claus Eckardt. In 23-gauge vitrectomy, the benefits of 25-gauge vitrectomy (transconjunctival trocar, no suture, reduced surgical trauma) are combined with the advantages of the 20-gauge technology (rigid instruments, more efficient vitrectomy, easy accessibility of the vitreous base) (Figs. 1.1 and 1.2). Finally, a new incision technique was developed: The sclerotomies are performed in a lamellar fashion (tunnel technique), which results in a better postoperative wound closure and less postoperative hypotony. The latest development is 27-gauge vitrectomy. The instruments have a diameter of only 0.4 mm. The company DORC has the 27-gauge vitrectomy with trocars in their product range. However, the indication spectrum for this technique is very limited. Possible indications are, for example, vitreous opacities or a central vitrectomy in the newborn. U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_1, © Springer-Verlag Berlin Heidelberg 2012

1

2

1

Introduction to Small-Gauge Vitrectomy

Fig. 1.1 An intraoperative image of a retinal detachment surgery with 4-port technique: the infusion line at the top right and the fixed fibre optic chandelier at the top left. Left and right below the two instrument trocar cannulas

Fig. 1.2 A postoperative image of the same detachment surgery: you can recognize the implanted intraocular lens and the almost white conjunctiva. A 20% SF6 tamponade was used

1.2

Key Features of ‘Micro-Incision Vitrectomy Surgery (MIVS)’

The techniques of 23-gauge and 25-gauge vitreoretinal surgery are also referred to as ‘micro-incision vitrectomy surgery’ (MIVS). The 23-gauge vitrectomy as well as 25-gauge techniques can now be used for more challenging posterior segment surgeries, including PVR retinal detachment and diabetic vitreoretinopathy with silicone oil. The main features are: • Lamellar and sutureless sclerotomies • Trocar cannulas • Bimanual surgery

1.2

Key Features of ‘Micro-Incision Vitrectomy Surgery (MIVS)’

3

Fig. 1.3 This histological section of an eye showing a lamellar cut through the sclera for 23-gauge vitrectomy. This tangential cut needs no suture. It is comparable to the tunnel cut in phacoemulsification

Fig. 1.4 23-gauge trocar with blue valve and blunt insertor. This model is from DORC. Other manufacturers such as Oertli or Geuder also offer trocar cannulas with valves

1.2.1

Sutureless Sclerotomy

The sclerotomies are performed with a tangential incision (lamellar tunnel incision), i.e. the sclerotomy is self-sealing and does not require suturing (Fig. 1.3).

1.2.2

Trocar

A trocar is a metal or plastic cannula which is placed transconjunctivally in the sclerotomy. The trocars are not sutured and remain in the sclerotomy during the entire surgery (Figs. 1.4 and 1.5). The trocar system is an essential part of the MIVS. It significantly lowers the anterior segment trauma and is associated with minor postoperative discomfort. Table 1.1 lists the advantages and disadvantages of the trocar. 25-gauge is superior to 23-gauge concerning the sclerotomy closure and the speed of postoperative recovery. A suture is sometimes necessary for 23-gauge sclerotomies but very seldom for 25-gauge sclerotomies. These characteristics are especially interesting for minor surgeries such as macular peeling.

4

1

Introduction to Small-Gauge Vitrectomy

Fig. 1.5 Trocar forceps for handling trocars, e.g. insertion of the infusion line. DORC. 1276.2

Table 1.1 Advantages and disadvantages of the trocar system Advantages Disadvantages Tangential incision (lamellar tunnel) at the Postoperative hypotony sclerotomy No suture required Angled instruments do not fit through trocars Trocar may be dislodged during removal of instruments Trocar openings easier to find for instrument Raised trocar openings may be covered by lids insertion than conventional sclerotomies in patients with small lid apertures No extensive opening of conjunctiva Transconjunctival vitreous prolapse (‘vitreous wick’) Trocars with valves enable a closed system Higher intraocular pressures during injection of gas or fluids Less foreign body sensation Low corneal astigmatism Faster postoperative recovery Rapid visual rehabilitation

1.2.3

Bimanual Surgery

During conventional vitrectomy procedures, the surgeon holds the light pipe in one hand and the vitreous cutter or a different ‘active’ instrument in the other hand (Fig. 1.6). In challenging situations, a more active second hand other than holding the light pipe can be useful. By inserting a fixed light probe (chandelier) in the sclera through a 4th sclerotomy port, the surgeon is enabled to use both hands actively (Fig. 1.7). The chandelier light illuminates the entire posterior segment with a panoramic view. Now, procedures such as indenting the retina and simultaneously performing a vitrectomy or bimanual peeling of membranes in PVR retinal detachment or diabetic retinopathy are easier to perform.

1.2

Key Features of ‘Micro-Incision Vitrectomy Surgery (MIVS)’

5

Fig. 1.6 An example of an operation with a 3-port trocar system. One infusion cannula and two instrument cannulas have been inserted. A handheld light pipe is used as a light

Fig. 1.7 An example of a surgery with a 4-port trocar system. In the 4-port trocar system, the fourth sclerotomy is used for a fibre optic chandelier, enabling the surgeon to work with two free hands. Synergetics. 25-gauge Awh Chandelier 56.20.25

Other advantages of the 23-gauge vitrectomy compared to the 20-gauge vitrectomy are: • Significant reduction of overall surgery time (no opening of conjunctiva, no sutures, and no cauterization of bleeding vessels) • Protects sclerotomies when inserting instruments • Easier to find the sclerotomies Bias against 23-gauge vitrectomy: • A persistent and widespread opinion concerning 23-gauge surgery is that the use of silicone oil is not possible or difficult. This is not correct. A silicone oil tamponade with 1,000 cSt silicone oil and its removal can easily be performed • A further notion is that the removal of the vitreous takes longer compared to 20-gauge systems In the meantime, this disadvantage has been overcome by the introduction of new high-speed cutters.

Equipment

2.1 2.1.1

2

Devices Operating Microscope

The optical quality of the surgical microscopes is excellent in all current models of the major manufacturers. For the retinal surgeon it is, however, important that several functions are integrated into the foot pedal, for example, a switch for choosing the microscope light or an inverter, if needed.

2.1.2

Binocular Indirect Ophthalmo Microscope (BIOM System)

To obtain a sufficient view of the posterior segment, one needs either a plano-concave contact lens which is directly placed onto the cornea, or a highly refractive lens (60D, 90D, 120D) which is placed in front of the lens of the surgical microscope comparable to indirect ophthalmoscopes. This results in an inverted image. By flicking a reversal system (so-called inverter) into the parallel beam path of the operating microscope, an upright image is created (e.g., using the “stereo diagonal inverter (SDI)” of Oculus) (see Appendix, Companies). We use the BIOM system (Binocular Indirect Ophthalmo Microscope) of Oculus and the EIBOS system by Moeller-Wedel. Both systems offer excellent optical images with a variety of different magnifications and fields of view. Based on our personal experience, the BIOM offers more flexibility and a better view of the retinal periphery. The EIBOS system is extremely robust and has the additional advantage of an inbuilt inverter that avoids the need for manual inversion when changing from the posterior segment to the anterior segment view during the surgery. Other companies also offer excellent alternatives, for example, Topcon (OFFISS) and Volk (OPTIFLEX).

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_2, © Springer-Verlag Berlin Heidelberg 2012

7

8

2

Equipment

The OFFISS system allows the surgeon to use the microscope light and to refrain from endoillumination. Thus, the central 40° of the retina can be viewed with the OFFISS system; for a wide-angle observation, an endoillumination is needed. The Topcon OFFISS system is used in combination with a special operating microscope from Topcon. The Volk OPTIFLEX system is relatively new on the market, and it offers good optical properties. So far, we have not had sufficient experience with this system in order to compare it to the other systems mentioned above. With the Oculus BIOM system, we use three different types of lenses: 120D for a wide peripheral view, 90D as our standard lens for most applications, and the 60D high magnification lens for macular surgery. In addition, an inverter is needed to invert the image for surgery (Fig. 4.7). This has to be turned on or off every time one switches between anterior segment or posterior segment view. We usually start with a 90D lens for core vitrectomy and posterior vitreous detachment. We then switch to the 120D lens to trim the vitreous base. We then switch to the 60D lens if we perform macular surgery. A good alternative is a planoconcave contact lens, which is placed directly onto the cornea. We then usually switch back to the 120D for complete trimming of the vitreous base and to inspect the peripheral retina for breaks. In cases of retinal detachment surgery, we recommend beginning the surgery with the wide-angle 120D lens to view the peripheral retina and to identify retinal breaks from the beginning of the surgery. Important: The BIOM provides a mirror image. Therefore, an inverter is installed in the microscope, which turns the mirror image of the BIOM. If you flick the BIOM in, activate the inverter to gain an accurate image. Similarly, if you flick the BIOM out, you have to activate the inverter in order to get an upright image.

2.1.3

Vitrectomy Machine

An extensive range of high-quality vitrectomy machines by several manufacturers are now available on the market. They have a cutting speed of approximately 2,500 cuts/min. Of great importance are the “fluidics” (vacuum, flow rate) of the machine. A sophisticated coordination of these parameters allows a high-speed and less traumatic vitrectomy in a closed system. Further, an easy switch between phaco- and vitrectomy-mode is important. In addition, the vitrectomy machines should have an active injection and extraction feature. This is utilized to inject or remove silicone oil. One can also connect the fluid needle to the active aspiration and work with active suction. This generation of vitrectomy machines has an integrated light source, which is sufficient for a light pipe but not for a chandelier light. An external light source and a laser must, therefore, be purchased separately. The latest generation of vitrectomy machines such as “Constellation” from Alcon or “Stellaris PC” from Bausch & Lomb have a cutting speed of 5,000 cuts/min. They provide an integrated light source that is strong enough for a chandelier light. The “Constellation” has an IOP control, an intergrated laser and a powerful fluid extraction mode, which reduces the surgery time for a silicone oil removal to 1–2 min.

2.2

Standard Instruments for Pars Plana Vitrectomy

2.1.4

9

Laser Device

Again, there are numerous providers of laser devices. A frequently used device is the 532-nm diode laser OcuLight GL from Iridex (see Chap. 7).

2.1.5

Cryo Console

A Cryo machine (DORC, ERBE) should be at our disposal in the operating room. Indications are a cryopexy of a retinal break, the retina, or the ciliary body due to neovascular glaucoma. Cryopexy is nowadays performed less frequently during vitrectomies because cryotherapy leads to more anterior segment trauma and is more difficult to perform through a closed conjunctiva compared to 20-gauge surgery with conjunctival incisions. In addition, cryotherapy has been associated with a higher rate of PVR formation in some studies of retinal detachment surgery. Finally, the chorioretinal scar formation appears several days later following cryotherapy compared to laser retinopexy.

2.1.6

Light Source

The light source is either external or can be integrated into the vitrectomy machine. In general, the internal light sources have traditionally been weaker than external light sources. When using a chandelier light, one has to use a very powerful light source. Synergetics offer an external photon source, and DORC and Alcon offer an external xenon light source (see Chap. 7). The new vitrectomy machines “Constellation” of Alcon and “Stellaris PC” from Bausch & Lomb have an internal light source that is strong enough for use with a chandelier light.

2.2

Standard Instruments for Pars Plana Vitrectomy

Retinal surgery is a very “instruments orientated” surgical discipline and necessitates that you acquaint yourself with the variety of high-quality microsurgical instruments designed for specific tasks, many more than with phacoemulsification. In order to become a good retinal surgeon, you need to know the different applications of this wide range of instruments and consequently increase your skills in this field of surgery. In addition, retinal surgery is “neurosurgery” in that one comes into direct contact with neural tissue. In general, such surgery is associated with the risk of transmitting Creutzfeldt–Jacob disease in countries where this disease is prevalent. Therefore, there is an increasing trend to use single-use instruments in vitreoretinal surgery wherever possible. Reusable instruments, which used to be the norm just a few years ago, are disappearing from the market. This is especially the case in the UK and France. The positive side effect for the surgeon is that one is always provided with new and sharp instruments of very high quality nowadays. On the

10

2

Equipment

Fig. 2.1 The new Alcon Edgeplus trocar with handle and scleral marker. Available for 23 gauge and 25 gauge

Fig. 2.2 Geuder one step trocar with handle. Geuder: G 33 445

downside, this can reduce the number of available instruments and options available to the surgeon. Further, this trend is also associated with higher costs. In the following section, various surgical instruments are introduced. One unfortunate trend in modern vitrectomy machines is that there are no international standards and the essential parts of the instrumentarium are usually not interchangeable between different manufacturers. Moreover, some manufacturers provide some of the essential tools as part of an “all-in-one” vitrectomy pack only. This means, for example, that a broken light pipe or a vitreous cutter that inadvertently touched the non-sterile part of the microscope can only be replaced by opening another surgical pack, which is more expensive than an individually packed single-use instrument. Therefore, the cost and availability of vitrectomy packs and the provision of spare instruments as individually packed units should be included in the negotiations regarding the purchase of a new vitrectomy machine. Trocar cannulas An increasing number of companies offer trocars for 23- and 25-gauge surgery (Alcon, DORC, Geuder, Oertli; Figs. 2.1 and 2.2). Depending on the manufacturer, these trocars are offered with or without valves and as a two-step (incision knife and trocar separately) or as a one-step system (incision knife and trocar combined). Trocars with valves are particularly useful for beginners, as they prevent hypotension and collapse of the globe during the surgery (Fig. 2.3a, b). It is however important to notice that with valved trocars, one works within a closed system. For example, when injecting fluid or gas, corresponding drainage or pressure control has to be ensured via the second port or the infusion system in order to avoid a significant rise in intraocular pressure. Using trocars without valves requires some manipulatory practice, as in certain situations, a plug needs to be inserted into the trocar in order to avoid hypotension (Fig. 2.4). The advantage of trocars without valves is that an intraocular hypertension, for example, when injecting silicone oil, is easier to control and to avoid. Today there is a clear tendency towards trocars with valves. We, therefore, recommend getting acquainted with valved trocars.

2.2

Standard Instruments for Pars Plana Vitrectomy

Fig. 2.3 (a) DORC 23-gauge trocars with valves. Intraocular fluid remains in the eye. The valves can be removed. (b) Alcon 23-gauge trocars with valves. The valves cannot be removed. Alcon: 8065751657

a

b

Fig. 2.4 Alcon 25-gauge trocars without valves. Intraocular fluid is flowing out of the trocars

11

12

2

Equipment

Fig. 2.5 Scleral marker. Braunstein fixed caliper. Bausch & Lomb, Storz instruments: E2402

Fig. 2.6 High-speed vitreous cutter. This 23-gauge vitreous cutter has a cut rate of 2,500 cuts/min. The newest vitreous cutter on the market by Alcon has a cut rate of 5,000 cuts/min. The advantages of the high-speed vitreous cutter can be particularly useful in a detachment surgery, as the detached retina remains very stable

Scleral marker Easy-to-use instrument to mark the position of the sclerotomy on the sclera: 3.5 mm for pseudophakic eyes and 4.0 mm for phakic eyes (Fig. 2.5). Some manufacturers (e.g., Alcon) incorporate a marker in the handle of the trocar blade, thereby avoiding the need for changing instruments at the beginning of the surgery. High-speed vitreous cutter High-speed vitreous cutters have a cut-rate of 2,500 cuts/min (Fig. 2.6). The new vitreous cutters from Alcon (Constellation) have a cut rate of 5,000 cuts/min. A 23-gauge (high-speed) vitrector cuts the vitreous body almost as fast as a normal 20-gauge cutter. High-speed cutters exert less strain on the retina and are therefore less traumatic. This enables manipulations closer to the retina with less risk of aspirating the retina and causing an iatrogenic break. This is possible due to a high flow rate (flow) in the central vitreous (the aspiration port of the vitrector is fully open) and a low flow rate in the periphery (the aspiration port of the vitrector is minimally open). With the foot pedal, one can switch between the two functions of the vitreous cutter: Firstly, you can cut and aspirate (vacuum) and secondly, you can only aspirate. Indications for combined cutting and aspirating are the removal of the vitreous, blood clots or soft lens fragments, iridectomy, etc.. Indications for aspirating are induction of PVD, aspiration of liquefied blood, subretinal fluid, etc.. The vitreous cutter cannot cut solid tissue such as fibrosed lens capsule or hard lens fragments. A fibrosed lens capsule is segmented and removed with scissors and forceps. Hard lens fragments necessitate the use of a fragmatome. This is currently not available for 25- or 23-gauge surgery. However, it is usually not a problem to enlarge one of the ports for the introduction of a 20-gauge fragmatome if needed (for details see chapter. 8). Combined fibre optic and vitreous cutter This vitreous cutter is combined with a light fibre. Indication: Vitrectomy of vitreous base. With one hand you can indent the retina and cut the vitreous base with the other hand. A better alternative is the use of a normal vitreous cutter and a chandelier light as the illumination is much better. (High-speed illuminated vitrectomy (2,500 cuts). DORC. 2267.IL).

2.2

Standard Instruments for Pars Plana Vitrectomy

13

Fig. 2.7 Fragmatome handpiece. Indication: Removal of a dropped nucleus. Alcon Accurus fragmatome. In addition, you need the fragmatome accessory pack (REF 1021HP)

Fragmatome The fragmatome can be used to emulsify a dropped nucleus in the vitreous cavity (Fig. 2.7). It is available in 23-gauge but is used without a trocar cannula. A fragmatome is difficult to use. On the one hand, it is less powerful than a normal phaco handpiece. On the other hand, it can exert high levels of suction in the posterior segment. Aspiration of the vitreous or the retina into the handpiece must be avoided. Lens fragments tend to jump away from the needle tip. In such cases, one must aspirate the fragments in the needle tip before emulsification (see Appendix, Materials). Light fibres (endoillumination) There are two types of endoillumination: hand-held light pipes (light probes) and fixed endoillumination (chandeliers). Light pipes are available with different sized cones of light. For routine cases, one holds the light pipe with the non-dominant hand and the vitreous cutter with the dominant hand. A chandelier light is fixed in the sclera and illuminates the entire fundus. This enables bimanual surgery and allows the surgeon to use a second active instrument in addition to the vitreous cutter. Chandelier lights are available from many different suppliers. The 25-gauge chandelier light of Synergetics has the great advantage of a rigid cable and a broad baseplate, which sticks firmly in the sclera. Good alternatives are the 25-gauge chandelier light of Alcon and the 23-gauge chandelier light of DORC which are easily inserted into a 25-gauge and 23-gauge trocar, respectively (for details, see Materials). More difficult to insert is the 27-gauge twinlight from DORC. It consists of two light fibres, which are both inserted at the 12 o’clock position. For optimal illumination of a chandelier light, an external light source (Photon, Xenon) is required. The choice of light source depends on the difficulty of the case and the personal preference of the surgeon. While chandelier lights have their definite advantages of freeing up your non-dominant hand to use a second instrument and provide better illumination for video recording of the surgery, a hand-held light probe still provides a more focussed and brighter light for most situations, for example, membrane peeling and delamination. It also depends on your routine method of trimming the vitreous base. One of the authors (HH) uses “traditional” hand-held endoillumination for the vast majority of routine cases (macular holes, retinal detachment, proliferative diabetic retinopathy) and performs trimming of the vitreous base using external indentation with the light pipe; this enables transscleral illumination of the

14

2

Equipment

Fig. 2.8 A 23-gauge fluid (backflush instrument). Passive aspiration: Leave the side opening open. Intraocular fluid will flow out through the side opening. If you press firmly on the silicone tubing, the fluid needle squirts fluid out, e.g., to remove epiretinal blood. DORC. 1281.C Fig. 2.9 A fluid needle with a silicone tip (backflush instrument with brush tip). Indication is non-traumatic work on the retinal surface. For example, if you wish to aspirate a residual perfluorocarbon droplet from the retina. DORC. 1281. BTD06

vitreous base whilst indenting the sclera from the outside with the light pipe. The other author (US) uses the hand-held light pipe only for macular peeling and for silicone oil removals. For all other cases, he uses a chandelier light which in his opinion opens a whole new world of surgical possibilities. Fluid needle The 23-gauge fluid needle is a blunt needle which aspirates liquid by capillary force and pressure difference. The handpiece usually contains a flexible or stiff plastic tube with an opening. This can be used in three ways: If the hole is uncovered, fluid will be pushed out of the eye through the tip of the fluid needle, exiting the eye through an opening in the handpiece driven by the intraocular pressure. The intraocular pressure is determined by the infusion pressure and the diameter and length of the cannula. If you place the index finger on the opening, there is no aspiration. If the hole is closed and the tubing is compressed, the fluid needle will eject the small amount of fluid within the eye. This can be used to flush the retina or an intraocular lens. There are two versions of fluid needles: with or without silicone tip (Figs. 2.8 and 2.9). With the silicone tip, more gentle manipulations close to the retinal surface are possible. However, these instruments are more expensive and usually not needed for most routine manipulations. Finally, one can connect the fluid needle to active aspiration (active injection mode) and, henceforth, increase the suction power (Fig. 2.10). Mastering the handling of the fluid needle is one of the key steps in improving the surgical skills of vitreoretinal surgeons (Fig. 2.11). Scleral depressor A scleral depressor indents the retina (Fig. 2.12). It is a standard instrument for pars plana vitrectomy. It is used for trimming of the vitreous base, in particular in retinal detachment surgery. With a 4-port vitrectomy and chandelier endoillumination, one

2.2

Standard Instruments for Pars Plana Vitrectomy

15

Fig. 2.10 Active aspiration: A fluid needle is attached to an infusion tube which is inserted into the vitrectomy machine. The active aspiration mode is activated. Close the opening of the tubing with your index finger and press the foot pedal. The intraocular fluid is aspirated into the vitrectomy machine

Fig. 2.11 If the fluid needle is clogged with debris, then flush the fluid needle by attaching a BSS-filled syringe

Fig. 2.12 A scleral depressor used to indent the retina. Geuder. G-32 715

can use the scleral depressor for bimanual trimming of the vitreous base using the vitreous cutter. Alternatively, one can use a light pipe for external indentation and transscleral illumination of the vitreous base. This is straightforward with 23-gauge light pipes; with the more flexible 25-gauge light pipes, one can perform this manoeuvre in the temporal and nasal quadrants by stabilizing the tip of the light pipe with the tip of your middle finger close to it. However, this is not possible at the 6 and 12 o’clock positions. One of the basic rules of vitrectomy is to finish all vitrectomies, no matter how “simple” and straightforward they are, with an internal search for retinal breaks at the vitreous base using endoillumination and a scleral depressor. When performing this examination, one has to make sure to view the entire retinal periphery over 360° up to the ora serrata. This is one of the most effective ways to reduce the rate of postoperative retinal detachments. Laser probe

16

2

Equipment

Fig. 2.13 A 23-gauge laser probe of DORC. The optical laser is curved so that the peripheral retina can be easily reached. DORC. 7223.IRI

Fig. 2.14 A 23-gauge endodiathermy handpiece. DORC. 1120.06

One can purchase straight or curved laser probes (Fig. 2.13). The curved laser is particularly suitable for the peripheral retina; the straight laser is easier for the central posterior pole. If you apply a peripheral laser treatment (break, peripheral ischemic retina), the use of a scleral depressor is recommended, which makes the break more accessible and avoids touching the lens. This can be performed either using a chandelier light and a scleral depressor or using the light pipe as a scleral depressor with transscleral illumination. Alternatively, you can use a laser fibre with endoillumination (see below). The use of the laser probe requires some training. A great proportion of intraoperative lens touch is caused by the tip of the endolaser. This is because the surgeon usually focuses on the area of illuminated retina that requires treatment and may forget about the position of the laser probe, in particular when indenting the vitreous base. One of the rules of laser treatment is not to cross the midline of the eye with the tip of the instrument when treating the retinal periphery on the opposite side. Curved laser probes can be advanced and retracted through a mechanism within the handpiece. This requires some training before operating safely within the eye. Also, the flexible part of the probe needs to be retracted before removing the instrument out of the eye. Otherwise, the probe will get stuck in the trocar, and the trocar will be removed with the instrument. Combined laser and light fibre handpiece This laser handpiece is combined with a light fibre. Indications: Peripheral retinal breaks or ischemic retinopathy. With one hand you can indent the retina with the scleral depressor and treat the break with the other hand (Illuminated Laser Probe, 23G with Iridex adapter. DORC. 7510.IRI). Endodiathermy probe An endodiathermy is useful for cauterizing bleeding retinal vessels such as in diabetic retinopathy (Fig. 2.14) or before large and more central retinectomies. Another indication is to mark a break in retinal detachment surgery or in preparation for a retinotomy. There are usually two different types of endodiathermy probes: “Active” endodiathermy probes are combined with a fluid needle. This is very useful when treating an acute intraocular haemorrhage. The fluid needle drains the haemorrhage, enabling localisation of the bleeding site, which can then simultaneously be treated

2.2

Standard Instruments for Pars Plana Vitrectomy

17

Fig. 2.15 23-gauge-Tano diamond dusted membrane scraper, which serves as a “tissue sweeper” for ILM or membranes. DORC. 1290.DSS06 Fig. 2.16 With the 25-gauge Spaide CRVO knife, we perform a slight incision of the membrane or the ILM. The scraped edge of the membrane or ILM can then be removed with an Eckardt forceps. DORC. 1293 LO.5

with endodiathermy. “Non-active” diathermy is a straightforward endodiathermy probe with a pointed tip. Appropriate use of the endodiathermy probe requires some training. If the settings are too strong or the tip is held too close to the retina, an iatrogenic retinal break can easily be created. Exodiathermy probe The exodiathermy is used to diathermize (bloody) episcleral vessels.

2.2.1

Instruments for Macular Surgery

Tano diamond dusted membrane scraper The instrument has a flexible diamond dusted silicone tip (Fig. 2.15). It is used for the peeling of the internal limiting membrane (ILM) or epiretianl membrane (ERM) by gently stroking the ILM until it tears. The ILM edge can then be removed with the Eckardt forceps. Neurotomy (CRVO) knife The neurotomy knife (Fig. 2.16) is a useful tool for manipulation of ERM. It is a good alternative to the Tano diamond dusted membrane scraper. You carefully stroke the membrane or ILM with the neurotomy knife until the membrane tears. The membrane edge can then be removed with the Eckardt forceps. In our opinion, the neurotomy knife is easier to handle than the Tano diamond dusted membrane scraper. The neurotomy knife from DORC is built only in a 25-gauge version, which can also be used together with 23-gauge cannulas.

18

2

Equipment

Fig. 2.17 A 23-gauge membrane pic, which is used for mobilization of membranes. This instrument can mobilize the edge of a membrane. The edge can then be grasped with forceps. Geuder. G-37 503

Fig. 2.18 A 23-gauge Eckardt forceps for precise grasping of an epiretinal membrane and ILM. DORC. 1286.W06

Membrane pic The membrane pic is angled at the end. It is very useful for the lifting of membrane edges (Fig. 2.17). A lifted membrane (edge) can then be removed with Eckardt forceps. Eckardt forceps and endgripping forceps The Eckardt forceps have two jaws and are an instrument frequently used for the manipulation of membranes, removal of ILM or ERM (Fig. 2.18). The endgripping forceps are a more powerful than the Eckardt forceps.

2.2.2

Instruments for Peeling for Diabetic Retinopathy and Traction Retinal Detachment with PVR

Serrated (Jaws) forceps These forceps have the shape of a crocodile jaw and exert more traction and grip than the Eckardt forceps. They are therefore more suitable for the removal of PVR membranes, grasping a dislocated IOL or intraocular foreign body (Fig. 2.19). Straight or horizontal scissors The horizontal scissors have two straight blades. They are used for dissecting membranes from the retina, for example, in proliferative diabetic retinopathy or PVR retinal detachment (Fig. 2.20).

2.2

Standard Instruments for Pars Plana Vitrectomy

19

Fig. 2.19 23-gauge serrated jaws forceps, which can be used for grasping thicker peripheral membranes. Not suitable for ILM. DORC. 1286.C06

Fig. 2.20 Straight or horizontal scissors. They are useful for cutting membranes in PVR retinal detachment or diabetes. Geuder. G: 36 578 or DORC. 1286.JO6

Fig. 2.21 The knob spatula has a beaded top. Indication: Non-traumatic massage of the retina, blunt manipulation of membranes and haemostasis. A very useful instrument. EyeTechnology: VR-2095

Knob spatula The knob spatula has a thick knob at its tip. Indication for use is the manipulation of membranes or a retinal massage. A retinal massage is necessary if there are retinal folds (Fig. 2.21). Retinectomy scissors (vertical scissors) These 23-gauge retinectomy scissors have two angled blades. They are used to create a retinectomy, for example, in PVR retinal detachment (Fig. 2.22).

20

2

Equipment

Fig. 2.22 The retinectomy scissors (vertical scissors) have angled blades with which you can cut the retina. Before doing this, you should cauterize the retina with endodiathermy. Geuder. Vitreous scissors angled. G 36 542 and DORC 1286.E06

2.3

What Instruments Are Needed for Different Interventions?

Standard equipment for surgeries with 3-port vitrectomy: Light fibre probe, vitreous cutter, scleral depressor, fluid needle Additional instruments in macular surgery Macular hole • Tano diamond dusted membrane scraper or neurotomy knife • Eckardt forceps Epiretinal membranes • Tano diamond dusted membrane scraper or neurotomy knife • Eckardt forceps • Membrane pic Standard equipment for surgeries with 4-port vitrectomy: Chandelier light, vitreous cutter, scleral depressor, fluid needle Additional instruments for various interventions Advanced proliferative diabetic retinopathy • Endodiathermy • Knob spatula • Membrane pic • Eckardt forceps • Straight vitreous scissors • Laser probe

2.4

Gases and Liquids

21

Retinal detachment • Endodiathermy • Endolaser probe PVR detachment • Eckardt forceps • Crocodile forceps • Knob spatula • Membrane pic • Neurotomy knife • Horizontal scissors • Endolaser probe • Endodiathermy • Retinectomy (vertical) scissors

2.4

Gases and Liquids

In posterior segment surgery, various gases and liquids are used. It is therefore important to understand their characteristics and abilities. The term phase is important. Phase is, with regard to physical properties, a spatially homogeneous field. One uses the term, for example, of a gaseous phase or liquid phase. A gas or liquid “bubble” refers to the spherical shape. Another important term is the meniscus: It refers to the curved surface of a liquid. If the term “water-filled eye” is used in this book, it means an eye filled with “balanced salt solution (BSS).” The BSS will be replaced postoperatively by aqueous humour. The following diagram (see Diagram 2.1) gives the location of the fluids and gases depending on their relative weight within the vitreous cavity. Perfluorocarbon and heavy silicone oils (Densiron 68®, Oxane Hd®) are heavier than water and are therefore located inferiorly. Heavy silicone oils are lighter than these heavy liquids. Water is again lighter and even lighter than water are conventional silicone oils. The lightest tamponades used are air or various gases; these are therefore always located on top. Choice of intraocular tamponade • ERM: BSS, air • Vitreous haemorrhage without retinal breaks: BSS, air • Macular holes: 20% SF6, long-standing hole: 15% C2F6, 1,000 cSt silicone oil Air / gas Conventional silicone oils Water Heavy silicone oils Perfluorocarbon

Vitreous space

Diagram 2.1 Relative location of liquids, oils and gases in the vitreous cavity

22

2

Equipment

• Proliferative diabetic retinopathy: air, 20% SF6, or light silicone oil • Primary retinal detachment: very often: 20% SF6, sometimes: 15% C2F6 • Redetachment: 15% C2F6, 14% C3F8, light silicone oil, and heavy silicone oils Air/gas tamponades are absorbed over several days to weeks. The gases differ in the duration of tamponade: Air 1–3 days, SF6 tamponades approximately for 3–4 weeks, and C2F6 and C3F8 tamponades about 1 and 2 months. Silicone oil tamponades are permanent tamponades and are usually removed between 4 weeks and 6 months after the initial surgery. Silicone oils with a lower viscosity (1,000 cSt conventional oil or heavy oils, which are a mixture of 1,400 cSt conventional oil and a heavy liquid) tend to emulsify earlier and are usually removed within 3 months. An advantage of these lower viscosity silicone oils is that they can easily be injected and removed with 25and 23-gauge ports. Higher viscosity 5,000 cSt silicone oils tend to emulsify later and can usually be left in within the vitreous cavity for longer periods of time. This usually requires at least one 20-gauge port for injection or removal. Very occasionally, 5,000 cSt silicone oil has to be left intraocularly as a permanent tamponade in cases with multiple redetachments after previously attempted oil removal or severe hypotony. Gases and conventional silicone oil tamponade breaks in the superior periphery from 8 o’clock over 12–4 o’clock. Oxane Hd® and Densiron 68® are suitable for support of the inferior periphery from 4 over 6–8 o’clock. Caution: Inject gases or liquids slowly into the eye (and never on the macula), as the injection pressure can cause retinal necrosis.

2.4.1

Perfluorocarbon

Perfluorocarbon (PFCL, heavy liquid) is heavier than water; the eye is filled up from the posterior pole to the ora serrata. In the supine position, PFCL exerts the most pressure on the posterior pole and less pressure anteriorly (Fig. 2.23); it flattens the retina from the posterior pole to the ora serrata (Fig. 2.23). A big advantage is the good visibility under PFCL. One disadvantage is that it always needs to be completely removed, as it is retinotoxic if left within the eye for weeks to months, especially if it is dislocated into the subretinal space. PFCL is now an essential tool in retinal detachment surgery. It is used to flatten the detached retina and push subretinal fluid through the breaks into the vitreous. Additional advantages are an instant apposition of photoreceptors and retinal pigment epithelial cells in order to promote reattachment and facilitate laser treatment around the breaks. It also stabilizes the detached retina, thereby facilitating trimming of the vitreous base and decreasing the risk of iatrogenic breaks during surgery. Because it does not mix with vitreous, it clearly delineates vitreous remnants in the anterior periphery. One can fill PFCL over the break without any problem; it will not spill through the break in the subretinal space due to its high surface tension. Finally, it can be used as a protectant of the posterior pole in cases of dislocated IOL or lens matter. Inject a small bubble of PFCL on the posterior pole in order to perform any necessary manipulations in these cases in some distance from the macula.

2.4

Gases and Liquids

23

Fig. 2.23 Opposite effects of air and PFCL in the vitreous cavity. Air exerts pressure onto the retina from anterior to posterior, whereas PFCL exerts pressure from posterior to anterior air water PFCL

Dislocation of PFCL into the subretinal space can occur in two situations: If there is a large retinal break with significant residual traction on the retina or if one injects PFCL too briskly, thus splitting the PFCL stream into multiple small bubbles that can then be “blown” through the break into the subretinal space.

Pits & Pearls No. 1 Injection of PFCL: There are two methods. (1) Bimanually: Using a backflush instrument cannula (Fig. 2.24) and a 5cc syringe. During injection, release pressure from the second trocar with a fluid needle. Otherwise, you create a dangerous excess pressure in the eye. (2) Monomanually: Injection with a double-barreled cannula (Fig. 2.25). A double-barreled cannula enables injection of fluid whilst maintaining the intraocular pressure. When fluid is injected, the intraocular pressure rises; this pushes fluid out of the eye through the second opening within the cannula. An intraocular hypertension is NOT possible. Therefore, only one hand is needed for injection with a double-barreled cannula (DORC. EFTIAR, dual bore cannula, 23 gauge/0.6 mm).

2.4.2

Air

In the supine position, air exerts the most pressure on the anterior retina (ora serrata) and less on the posterior retina (Fig. 2.23). Because air is lighter than water or PFCL, the eye will be filled with air from the ora serrata and then down to the optic disc. To fill the eye completely with air, the surgeon must aspirate the liquid behind the

24

2

Equipment

Fig. 2.24 23-gauge backflush needle. This cannula is used for the fluid needle and for injection of fluids. DORC 1281.A5D06

Fig. 2.25 Double-barreled cannula. This cannula is used for the injection of fluids. The cannula prevents an intraocular hypertension during injection. DORC: Double-bore cannula. EFD.06 Fig. 2.26 View onto a fundus of a water-filled eye. The peripheral view is reduced by water; the advantage is a higher resolution

air bubble with a fluid needle. This is most easily done by holding the fluid needle just above the optic disc until the liquid is completely removed. Air is important in detachment surgery for the fluid/air exchange manoeuvre in which a detached retina can be flattened with air. In addition, air can be used at the end of surgery as a tamponade in eyes with vitreous haemorrhage to prevent a possible postoperative bleeding.

2.4

Gases and Liquids

25

Fig. 2.27 View onto a fundus of an air-filled eye. The peripheral view is extended up to the ora serrata; the disadvantages are a lower resolution and the difficulty to identify retinal breaks

Another indication for an air-filled eye is a better sealing of the sclerotomies. The air exerts pressure on the wedges of the tunnel sclerotomies and induces an improved closure of the sclerotomies. A disadvantage of air and gases in general is the greater distortion of the optical image. One advantage is the wide-angle view up to the pars plana in an air-filled eye (Figs. 2.26 and 2.27).

Pits & Pearls No. 2 BIOM and air: When filling air into the vitreous cavity, the image is out of focus due to the different refractive index. If you move the BIOM lens up a little, the image becomes focussed again.

2.4.3

Expanding Gases

SF6, C2F6, and C3F8 are expanding gases as dissolved nitrogen diffuses along the concentration gradient from the blood into the gas bubble and accumulates here. The postoperative extension may lead to strong increases in intraocular pressure when the gases are injected undiluted into the eye. To avoid this intraocular pressure rise, expanding gases are used in a concentration in which they do not expand.

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Equipment

Table 2.1 Properties of gases and liquids for a tamponade (Densiron 68® is heavier than Oxane Hd® (see density) but almost as viscous as 1,300 cSt silicone oil (see viscosity) and therefore almost as easy to remove) Tamponade Concentration Gas duration (days) in % Indication Air 7 Vitreous haemorrhage, diabetic retinopathy, epiretinal membrane 14–21 20 Superior breaks from 8 to 4 o’clock, SF6 macular hole, diabetic retinopathy 30 15 Inferior breaks, PVR detachment C2F6 60 14 Inferior breaks, PVR detachment C3F8 Silicone oils Density (viscosity) Months (g/cm³) Silicone oil (1,000 Approx. 3–6 0.97 Multiple breaks, PDR, PVR, trauma, and 1,300 cSt) choroidal detachment, endophthalmitis Silicone oil >= 12 0.97 Multiple breaks, PDR, PVR, trauma, (5,000 cSt) choroidal detachment 2 1.02 Inferior breaks, inferior PVR Oxane Hd® (3,500 cSt) detachment 3–4 1.06 Inferior breaks, inferior PVR Densiron 68® (1,400 cSt) detachment

The non-expanding concentration of SF6 is 20%, of C2F6 15%, and of C3F8 14% (see Table 2.1). Air does not expand. Patients with a gas-filled eye should not undergo anaesthesia with nitrous oxide, as it diffuses into gas-filled cavities and leads to an increase of volume. In addition, any air travel or trips to locations at greater heights (e.g., patients living in mountainous areas) are strictly prohibited. This should be part of any routine consent procedure before vitreoretinal surgery. We also advise on giving patients information leaflets with detailed instructions for themselves and referring physicians regarding these precautions. SF6 (sulphur hexafluoride) The commonly used concentration of sulphur hexafluoride (SF6) is 20%. It tamponades the eye for approximately 4 weeks. Indication: macular holes, diabetic retinopathy, and retinal detachment surgery with superior breaks. SF6 is not suitable for inferior breaks unless a specific posture can be maintained for prolonged periods of time (e.g., supine position or on one side opposite to the break). C2F6 (perfluoroethane) The usual concentration of C2F6 is 15%. It tamponades the eye for approximately 4–6 weeks. Indication: difficult detachments with multiple breaks, inferior tears, or PVR detachment. C3F8 (perfluoropropane) The usual concentration of C3F8 is 12–14%. It tamponades the eye for approximately 8 weeks. The indications are similar to C2F6.

2.4

Gases and Liquids

27

Fig. 2.28 An expanding gas is injected through the IV line to the top right into the eye. To the bottom right, a fluid needle is held in a cannula to relieve intraocular pressure

Pits & Pearls No. 3 Injection of gas 1. Errors in preparing the correct concentration of the air–gas mixture are potential recipes for disasters if different gases with varying concentrations are used regularly in one theatre. Concentration levels, which are too high, can lead to a massive rise in the intraocular pressure, whereas lower concentrations may result in a shorter tamponade than desired. In every theatre, a strict protocol for preparing the air–gas mixture must be followed. We recommend that every surgeon supervises the preparation of the mixture and checks on the gas used. 2. Gases are in 100% concentration in gas containers. They must be diluted with air before injection into the eye. Example: 20% of SF6. 50 ml syringe: draw 10 ml 100% SF6 in the syringe and dilute to 50 ml with room air 3. If you intend to inject a gas into the eye, first perform a fluid–air exchange. The gas-filled syringe is then connected to the three-way tap. The scrub nurse can inject the gas. At the same time you hold a fluid needle behind the lens to release pressure so that the globe remains normotensive (Fig. 2.28). Always leave some 5–10cc in the syringe. This gives you some extra volume to inject should the globe be hypotensive after removing the trocars.

2.4.4

Light Silicone Oils

Conventional silicone oil is lighter than water and floats in the vitreous and in the anterior chamber. Indications for silicone oil tamponade are retinal detachments with multiple (superior and inferior) breaks, a giant tear, advanced proliferative diabetic retinopathy, PVR detachment, and a macular hole (if a prone position is not possible).

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Equipment

Fig. 2.29 Silicone oil injection set. The infusion line is attached to the vitrectomy machine, and the “active injection” mode is activated. DORC 1363.DD

Fig. 2.30 23-gauge silicone oil cannula. This cannula is screwed to the syringe in Fig. 2.23 and fits through a trocar. DORC 1272.VFI06 or Med One: 3241st PolyTip Cannula 23-gauge 10 mm (Sanisoglu)

Conventional silicone oils are available with different viscosities of 1,000 cSt (centistokes), 1,300 cSt, 2,000 cSt, and 5,000 cSt. 1,300 cSt silicone oil is more and more replaced by 1,000 cSt silicone oil. 1,000 cSt silicone oil emulsifies more rapidly and is suitable for a tamponade of about 3 months and can easily be injected and withdrawn through 25- and 23-gauge trocars (see above). 5,000 cSt silicone oil emulsifies less rapidly and is suitable for tamponades of a longer duration; however, at least one 20-gauge port is usually necessary for injecting or removing 5,000 cSt silicone oil.

Pits & Pearls No. 4 Injection of silicone oils: For the injection of silicone oils you will need an injection set (Fig. 2.29). A 23-gauge plastic cannula is screwed into the syringe (Fig. 2.30). With the help of “active injection” modus, the silicone oil is injected into the eye.

2.4.5

Heavy Silicone Oils (Densiron 68® and Oxane Hd®)

Densiron 68® and Oxane Hd® are mixtures of silicone oil and PFCL and are known as heavy silicone oils (Fig. 2.31a, b). They are heavier than water and, therefore,

2.4

Gases and Liquids

Fig. 2.31 (a) Tamponade with Densiron 68® in an eye model. The blue fluid is aqueous. Densiron 68® is less convex than Oxane Hd® and therefore tamponades the inferior retina better. Densiron 68® is widely accepted by vitreoretinal surgeons. With friendly permission of Dr. David Wong. (b) Tamponade with Oxane Hd® in an eye model. Oxane Hd® is much lighter than Densiron 68®. It is much more convex and tamponades the inferior retina less effectively than Densiron 68® (With friendly permission of Dr. David Wong)

29

a

b

support the inferior periphery. Indications are multiple inferior breaks, PVR detachment, retinal detachment with giant tear, and a traumatic detachment. Since Oxane Hd® and Densiron 68® consist partially of PFCL, they should not come in contact with pure PFCL for longer periods of time. However, a short contact (e.g., during direct PFCL heavy silicone oil exchange) is possible. Oxane Hd® should be removed after 2 months and Densiron 68® after about 3–4 months as their tendency to emulsify is comparable to 1,300 cSt conventional silicone oil. The features of these tamponades are summarized in Table 2.1. Important: There is no 100% tamponade, neither for gases nor for oils. This is because any tamponade will form the smallest possible surface, thereby forming a

30

2

Equipment

sphere within the eye that will never be able to cover all areas of the inner surface of the eye. This is also true for so-called double tamponades of silicone oil and PFCL. These two substances will mix well, but then they will form an hourglass-shaped tamponade within the eye with one part trying to folate upwards and one part sinking down. As a result, a belt of fluid surrounds the tamponade in the middle of the eye. Finally, a “complete” vitrectomy is not possible. Remnant vitreous will always lead to an incomplete tamponade.

2.5 2.5.1

Dyes for Vitreous and Membranes Staining of the Vitreous

Staining: triamcinolone acetonide, trypan blue (Monoblue®, Membrane Blue®) Triamcinolone is a frequently used dye in vitreoretinal surgery. Many surgeons inject it at the beginning of the vitrectomy because triamcinolone stains the vitreous well (comparable to asteroid hyalosis). In addition, triamcinolone is a popular staining agent for membranes but does not stain the ILM. Trypan blue can also be used instead of triamcinolone (Table 2.2). Practical use: For the injection of dyes, take a 3 ml syringe and a 23-gauge backflush needle (Fig. 2.24). Inject before the vitrectomy 0.1–0.2 ml diluted triamcinolone, wait approximately 10 s, and then continue the vitrectomy. You will now be able to recognize the vitreous well.

Pits & Pearls No. 5 Triamcinolone can be cumbersome to remove. If you inject too copiously, it will cover potentially important details of the retina and slow down the procedure. Use only minimal amounts of triamcinolone for staining; you can always re-inject if necessary.

2.5.2

Staining of Epiretinal Membranes

Staining: triamcinolone acetonide, Trypan blue (Monoblue®, Membrane Blue®, MembraneBlue Dual®). Triamcinolone crystals stick onto the membranes, while Trypan blue stains the entire membrane. Our best experience has been with Monoblue®. Practical modalities include: slow injection (syringe with a blunt cannula) of dye onto the posterior pole (Monoblue® is heavier than water), wait about 15 s, open the infusion, and remove the dye again with the fluid needle. Practical use: For the injection of dyes, take a 3 ml syringe and a 23-gaugebackflush needle (Fig. 2.24). Perform a PVD, inject dye slowly onto the posterior pole (Monoblue® is heavier than water), wait about 15 s, open the infusion, and remove the dye again with the fluid needle.

2.5

Dyes for Vitreous and Membranes

Table 2.2 Staining properties of different dyes Vitreous Triamcinolone + Trypan blue + Brilliant blue G −

2.5.3

31

Membranes + ++ +/−

ILM − +/− ++

Staining of the Inner Limiting Membrane (ILM)

Staining: Brilliant Blue G (Brilliant Peel®, ILM-Blue®, MembraneBlue Dual®). Indocyanine green (ICG) is controversial as it is potentially neurotoxic and may cause visual field defects. Triamcinolone does not stain the ILM, and Trypan blue stains the ILM only weakly. We have had the best experience with Brilliant Peel®. Practical approach: Perform a water–air exchange; leave a small puddle of water. Inject 2–4 drops of Brilliant Blue G in the puddle and wait approximately 30–60 s. Then aspirate the puddle with the dye and perform an air/fluid exchange. Advantage: The dye acts only in the water puddle, and the surgeon can remove it more quickly than if you stain the entire vitreous cavity. (See Chapter 5.3: macular holes and epiretinal membranes.) Remark: An interesting dye is MembraneBlue Dual® (DORC). It contains both Trypan blue and Brilliant Blue G and can, therefore, stain membranes and ILM at the same time.

General Considerations and Techniques of Pars Plana Vitrectomy

3.1

3

General Considerations

As any surgical procedure, pars plana vitrectomy is learned in four steps: observation; performing sections of the procedure and then the entire surgery under supervision; performing the surgery without supervision but with an experienced surgeon as a backup close by; performing the surgeries on your own. There is no shortcut to this process. However, with regards to pars plana vitrectomy, valuable knowledge and skills can be gained before starting to perform the surgery.

Pits & Pearls Assist experienced surgeons as much as you can before you begin to perform vitrectomy. You will automatically acquire the basic ‘do’s and don’ts’ during these procedures. Get scrubbed to assist; this is the only way to get really involved, and you will learn a lot more than by just looking at a TV screen or the surgeon´s shoulder.

Pits & Pearls Examine all vitrectomy patients the day before the surgery. Overnight plan how you intend to operate on each patient (anaesthesia, surgical procedure, instruments, dye and tamponade). As a rule of thumb, assist in every type of surgery from silicone oil removal to retinal detachment ten times. Then you will have acquired specific knowledge on how a particular pathology is managed.

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/978-3-642-23294-7_3, © Springer-Verlag Berlin Heidelberg 2012

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General Considerations and Techniques of Pars Plana Vitrectomy

Pits & Pearls ‘You see only what you look for, you recognize only what you know’. Acquire a broad knowledge of medical retina and develop your skills with binocular indirect ophthalmoscopy. If you master indirect ophthalmoscopy, you will be able to see things others will miss, in particular when there is a poor view of the fundus (for example, vitreous haemorrhage with some areas of the peripheral retina still visible or a gas-filled eye). With a sound knowledge of medical retina, you will be able to establish the correct diagnosis before and during the surgery in certain cases. These skills will help you to plan your strategy for surgery, deal with unexpected findings during the surgery (for example, unusual retinal changes after removing a vitreous haemorrhage) and finally, avoid unnecessary interventions.

Pits & Pearls If possible, try to learn and master cataract surgery before learning pars plana vitrectomy. This will not only teach you the ABC of ophthalmic surgery under an operating microscope but will also be very useful in cases of combined surgeries or anterior segment problems during the vitrectomy (for example, silicone oil prolapse, dislocated IOL or lens touch).

Pits & Pearls Acquire a good knowledge of ultrasound echography and perform this examination yourself before your surgeries. This will enable you to construct a 3D image of the situation in front of you in cases of vitreous haemorrhage or poor view, help you to avoid unnecessary surgeries and help you in developing the correct strategy for the surgery.

Pits & Pearls Learn and practise scleral buckling surgery. This technique is still unsurpassed in localized retinal detachments, in particular in young and phakic patients with an attached vitreous. If you do not practise it, you will be unable to give the appropriate treatment to a child with a traumatic retinal detachment and an ora dialysis, for example.

3.4

3.2

Complicated Surgeries for Advanced Surgeons

35

Patient Selection

Before performing pars plana vitrectomies without supervision, the beginner should learn the techniques of pars plana vitrectomy (PPV) step by step. Most routine surgeries are suitable, in particular in pseudophakic eyes, silicone oil removals or eyes with vitreous haemorrhage and an attached retina.

3.3

Recommended Learning Steps for Beginners

We recommend the beginner to train the following steps (the steps can be practised separately): 1. Insertion and removal of trocars and suturing of sclerotomies. We recommend that the conjunctiva be opened before suturing the sclerotomy. 2. Use of the light pipe and focussing the image with the BIOM. 3. Staining of the vitreous (for example, with triamcinolone) and core vitrectomy. 4. Induction of posterior vitreous detachment. 5. Trimming of the vitreous base with bimanual technique (chandelier light). 6. Peeling of an epiretinal membrane. You can then perform the first surgeries from beginning to end. The following pathologies may be appropriate (with rising difficulty level). Easy – more advanced surgeries 1. Silicone oil removal with passive and active aspiration with use of the BIOM 2. PPV in diabetic retinopathy with vitreous haemorrhage without tractional retinal detachment and PRP 3. ERM removal 4. ILM peeling 5. Dislocated IOL (sclerafixation of IOL) 6. Dislocated (hard) nucleus

3.4

Complicated Surgeries for Advanced Surgeons

The following surgeries are hard nuts, which can be cracked with a little training. All surgeries demand a thorough and correct preoperative assessment. Draw up a plan on how you wish to proceed intraoperatively. An advanced proliferative diabetic retinopathy with tractional detachment can be very difficult to handle. A PVR detachment is technically challenging and demanding. Last but not least, the subchoroidal haemorrhage is an especially difficult surgery. You can be proud of yourself if you can manage this pathology.

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General Considerations and Techniques of Pars Plana Vitrectomy

Difficult surgeries 1. Endophthalmitis 2. Retinal detachment 3. IOFB 4. Difficult proliferative diabetic retinopathy (PDVR) 5. PVR detachment 6. Subchoroidal haemorrhage Time perspective: If you perform 2–4 PPVs per week, one needs after our experience 3 months to operate an ILM peeling on your own and 6 months for a detachment PPV.

3.5

Anaesthesia

The choice of anaesthesia is influenced by a variety of factors. It depends on the estimated duration and severity of the procedure as well as the preferences of the patient and the surgeon. Finally, organizational procedures also have to be considered (for example, out of hours, anaesthetic cover, changeover times in theatre, etc.). Ideally, beginners should learn the first steps while the patient is under general anaesthesia. This greatly reduces stress levels for the surgeon, minimizes sudden head and eye movements and allows for more discussion between the experienced and the student surgeon, and finally, as the surgical experience increases, more and more surgeries can be performed under local anaesthesia. Experienced retinal surgeons can perform almost all surgeries under local anaesthesia. As a rough guideline, we usually perform macular surgeries and other vitreoretinal procedures up to 60 min estimated operating time under local anaesthesia. The most painful surgical steps are indentation of the vitreous base, traction on rectus muscles and cryotherapy. Procedures involving scleral buckling surgery are, therefore, commonly performed under general anaesthesia, in particular in younger patients. Several colleagues have experienced good results with subtenon anaesthesia. This usually needs to be topped up before starting the procedure to avoid excessive eye movements. One advantage of this technique is that it is classified as ‘blunt needle’ anaesthesia. In many departments, this avoids the need for the presence of an anaesthetist in theatre, which may facilitate out-of-hours surgeries in units in which the anaesthetic cover has to be shared with other surgical specialities. For straightforward combined phaco/vitrectomy, we use a combination of shortand long-acting local anaesthetic. The preferred techniques of the authors are: US: Usually 3 ml solution (e.g. 50% bupivacain (Marcain®) and 50% mepivacain (Carbocain®)) inferotemporal and 2 ml superior at 12 o’clock next to the eyeball. For a PPV detachment, we recommend the following peribulbar anaesthesia: 4–4–2. 4 ml solution (50% bupivacain and 50% mepivacain) inferotemporal, 4 ml superonasal and 2 ml through the caruncle. HH: Retrobulbar anaesthesia with sharp 1 ½ in. retrobulbar needle, a mixture of 5 ml lignocaine 2%, 5 ml bupicavaine 0.5% and Hylase (150 IU I 1 ml) is used,

3.6

Combined Surgery: Phaco/IOL and Pars Plana Vitrectomy

37

and about 6–8 ml of this mixture are injected. Hylase is hyaluronidase, which is an enzyme that can be added to the local anaesthetic solution when administering peri- or retrobulbar anaesthesia. It promotes akinesia and is standard in some departments, whereas it is never used in others.

Pits & Pearls If revisional surgery within several days of the initial surgery is necessary, consider general anaesthesia, in particular after retinal detachment surgery with cryotherapy and extensive extraocular manipulations. The local anaesthetic is less effective in inflamed tissue, and the procedure can be more painful under local anaesthesia than anticipated.

Pits & Pearls When performing potentially painful surgery under general anaesthesia (cryotherapy, extensive extraocular manipulations), consider giving a small amount of subtenons anaesthesia at the end of the surgery. This significantly reduces the pain in the immediate postoperative period when the patient is waking up and recovering from the general anaesthesia.

Pits & Pearls No. 6 If you are using Hylase with retrobulbar anaesthesia, one vial can be used for multiple cases during one surgical session. We routinely dilute one vial (1,500 IU) with 10 ml saline for injection and then use 1 ml of this added to our local anaesthetic mixture.

3.6

Combined Surgery: Phaco/IOL and Pars Plana Vitrectomy

There is an increasing trend towards combined surgery (phaco/IOL + vitrectomy) in patients over 60 years. This prevents the need for a second procedure (phaco/IOL) that will be required in almost every patient in this age group within 1–2 years postoperatively. Additionally, the disadvantages of cataract development (decreased vision, increasing myopization, need for additional examinations) are avoided. Finally, manipulations at the vitreous base are significantly easier to perform in

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General Considerations and Techniques of Pars Plana Vitrectomy

pseudophakic patients. This is of particular importance in retinal detachment cases. A lens touch is a serious complication. It will always result in rapid cataract development and creates a potential point of capsular damage during phaco/IOL. This again may cause prolapse of the posterior segment tamponade into the anterior chamber. It must also be mentioned that several colleagues try to avoid combined surgery if possible, even in patients above the age of 60 years or patients with moderate cataracts. The reasons for this are that the lens also has a potential barrier function between the anterior and posterior segment. Increasing anterior chamber inflammation can sometimes be seen following combined surgery. In addition, more anterior segment problems can be seen compared to a two-step approach (for example, posterior synechiae or lens capture). Finally, some authors argue that the additional anterior segment trauma together with the loss of barrier function may also increase posterior segment inflammation and may cause higher rates of cystoid macular oedema. These hypotheses have never been examined in a prospective randomized trial. The authors usually combine vitrectomy with phaco/IOL in patients with moderate to advanced cataracts and in patients above the age of 60 years. In patients under 60 years with a clear lens, a lens-sparing vitrectomy should be performed.

Pits & Pearls If at all possible, try to establish biometry and IOL calculations as part of the routine preoperative assessment in all cases of phakic patients undergoing pars plana vitrectomy. This will enable you to perform unplanned phaco/IOL in cases of intraoperative lens touch if needed and provide you with the correct biometry should you need to use silicone oil as a tamponade (which greatly impairs the precision of biometry measurements).

There are two major surgical steps to understand and become skilled at if you wish to master pars plana vitrectomy: (1) To correctly assess the relationship of the posterior vitreous face and the retina, leading to completion of a posterior vitreous detachment (PVD) during surgery; and (2) trimming the vitreous base and operating in this area without touching the lens in phakic eyes. Therefore, before the start of any pars plana vitrectomy, always ask yourself two questions: Is a PVD present and is the eye pseudophakic or phakic? A PVD should be induced in all posterior vitrectomies (some authors propose not to induce a PVD in asteroid hyalosis or floaters, as the vitreous cortex adheres firmly to the retina and a PVD can induce breaks; however, a PVD will eventually occur in most of these patients, and this can either result in a ‘recurrence’ of floaters or retinal breaks). The attached posterior vitreous is more important than most people think. It is involved in many retinal pathologies (maculopathy, diabetic retinopathy) and should therefore be removed by a PVD. For the beginner, the induction of PVD is often not easy. A PVD can be seen at the slit lamp or by ultrasound. Intraoperatively, you can stain the vitreous to determine if a PVD is present or not.

3.7

3-Port or 4-Port Vitrectomy

39

Fig. 3.1 An example of an operation with a 3-port trocar system. One infusion trocar with infusion line and two instrument trocars

Fig. 3.2 An example of a surgery with a 4-port trocar system. In the 4-port trocar system, the fourth sclerotomy is used for an optic fibre chandelier, enabling the surgeon to work with two free hands

3.7

3-Port or 4-Port Vitrectomy

A distinction is made between a 3-port vitrectomy and a 4-port vitrectomy (Fig. 3.1). The difference is that in a 4-port vitrectomy, a fourth port is used for a chandelier light, which is best placed in an inferonasal position (Fig. 3.2). Before starting a vitrectomy, you have to decide whether you want to perform a 3-port or 4-port vitrectomy and inform the theatre staff accordingly. However, you can always add a fourth port during 3-port PPV if needed.

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3.7.1

General Considerations and Techniques of Pars Plana Vitrectomy

Conventional 3-Port 23-Gauge Vitrectomy

In monomanual vitrectomy, one hand holds a light pipe and the other hand holds the vitreous cutter or a different active instrument. The 3-port vitrectomy is sufficient for most surgical indications. A good help for detachment surgery consists of using an illuminated endolaser or an illuminated vitreous cutter (see chapter on instruments). These combined instruments can be used in combination with a scleral depressor.

3.7.2

Bimanual 4-Port 23-Gauge Vitrectomy

With the introduction of new chandelier lights and powerful external light sources (Photon, Xenon), more and more vitreoretinal surgery is performed with two active hands (bimanual). Instead of a handheld light pipe, a chandelier light is fixed in the sclera. The extent of bimanual surgery differs between the authors. US performs bimanual surgery for almost all pathologies except for macular surgery or silicone oil removal. HH uses 4-port vitrectomy in cases of challenging membrane peeling (trauma, advanced cases of retinopathy of prematurity or von Hipple-Lindau disease, difficult proliferative diabetic retinopathy or PVR retinal detachment). The surgeon then has two active hands to manipulate membranes. This is of particular advantage in very strong adhesions between retina and the posterior vitreous face or epiretinal membranes.

Pits & Pearls Try to use chandelier lights in your uncomplicated cases in order to practise their insertion and to trim the vitreous base bimanually with scleral depressor and vitreous cutter. This will give you greater control when you really need them in challenging cases.

4

Special Techniques for Pars Plana Vitrectomy

4.1

Topography in Vitrectomy

Lens = front or anterior, retina = back or posterior. A peripheral break is equivalent to an anterior break, and a central break is equivalent to a posterior break (Fig. 4.1). 12 o’clock is up, 6 o’clock is below. You make a sclerotomy not below the limbus but behind or posterior to the limbus. You move the vitreous cutter from the back (retina) to the front (lens). Before limbus Behind limbus Anterior Peripheral

ol cm

Fig. 4.1 Topography of the eye

te

r

Posterior or central

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/978-3-642-23294-7_4, © Springer-Verlag Berlin Heidelberg 2012

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4.2

4

Special Techniques for Pars Plana Vitrectomy

Pars Plana Vitrectomy Step by Step

In the following section, a standard pars plana vitrectomy is explained. As in a cookbook, the ingredients (instruments, dyes, tamponade) are listed first and then the practical approach is explained in detail step by step. Instruments 1. 3-port trocar 2. 120D or 90D magnifying glass 3. Light pipe 4. Vitreous cutter 5. Scleral depressor 6. Fluid needle Dye Triamcinolone Tamponade Air, gas, silicone oil Individual steps 1. Insertion of trocar cannulas 2. Phacoemulsification 3. Focussing 4. Core vitrectomy 5. Induction of posterior vitreous detachment 6. Trimming of vitreous base 7. Anterior vitrectomy 8. Internal search for retinal breaks 9. Laser photocoagulation of peripheral breaks 10. Cryotherapy of peripheral breaks 11. Intraoperative tamponade 12. Postoperative tamponade 13. Removal of trocar cannulas 14. Sclerotomy sutures 1. Insertion of trocars The sclerotomies must be placed in the pars plana (there is no retina). The distance DVD

Video 1 Insertion of trocar cannulas

of the sclerotomies to the limbus is 3.5 mm in pseudophakic eyes and 4.0 mm in phakic eyes (Table 4.1). By using a scleral marker, you can measure and mark the sclerotomy. It is recommended that you always (even after the beginner phase) use

4.2

Pars Plana Vitrectomy Step by Step

43

Table 4.1 Site of sclerotomy in relation to the age (Lemley and Han 2007) Age

0

Site of sclerotomy (mm)

1.0

1–6 months 1.5

6–12 months 2.0

1–3 years 2.5

3–6 years 3.0

6–18 years 3.5

Adult phakic 4.0

Adult pseudophakic 3.5

Fig. 4.2 Practical approach for the insertion of the trocar cannula. The right hand pulls the conjunctiva back with a cotton wool swab. The left hand marks the injection site with the scleral marker

Fig. 4.3 The right hand fixates the conjunctiva. The left hand pierces the sclerotomy knife at an angle of 15º into the eye

this scleral marker to avoid unnecessary complications due to misplaced sclerotomies. There is no pars plana in newborns; refer to Table 4.1 for recommended placing of sclerotomies in children. The insertion of the trocars is an important step. It may look frightening at the beginning, but is actually is easier than it looks (Figs. 4.2–4.6). In general, the currently

44 Fig. 4.4 The left hand inserts the trocar exactly in the puncture site marked by a bleeding

Fig. 4.5 The eye should look like this after insertion of the trocars. Note: The trocars for the instruments are located at 2:00 till 2:30 and 9:30 till 10:00

Fig. 4.6 An eye after removal of all trocar cannulas. We see no leakage (no air or fluid under the conjunctiva in the area of sclerotomies). A suture is not necessary

4

Special Techniques for Pars Plana Vitrectomy

4.2

Pars Plana Vitrectomy Step by Step

45

used trocar systems can be divided into two groups: one-step and two-step systems. A one-step system uses a sclerotomy knife inside the trocar. Similar to a venflon cannula, trocar and knife are introduced in one step; the knife is then withdrawn, and the trocar remains in the sclera. With the two-step approach, the sclerotomy is made with a sclerotomy knife, and in a second step, the trocar is introduced through this opening. The advantage of the one-step system is that it simplifies the introduction of the trocar, as one does not need to search for the sclerotomy site, in particular if the conjunctiva has been ballooned through the local anaesthetic or during previous phacoemulsification. Further, there is no danger of pushing conjunctiva through the sclerotomy. The disadvantage of the one-step system is that the knife usually is not as sharp as the ones used for the two-step approach. The resulting sclerotomy wounds are usually slightly more irregular than the ones created by the two-step knifes and, therefore, may not seal as well. This may lead to postoperative hypotony and loss of tamponade, in particular with the 23-gauge systems. It has to be said, however, that the latest generation of one-step knifes have improved immensely compared to previous models. Therefore, more and more surgeons are now switching to one-step systems.

Pits & Pearls No. 7 Choose the position of sclerotomies wisely. Try to place your hands in a comfortable position, mimicking your working position in order to identify the best position for your sclerotomies before inserting the trocars. The standard position is 4 o’clock (left) or 8 o’clock (right) for the infusion and 9:30–10 and 2–2:30 o’clock for your working ports. See Diagram 4.1. The best position for the chandelier light is inferonasally because only in this position it does not interfere with the rotation of the globe. In phakic eyes, we recommend that you move your working ports closer to the 3 and 9 o’clock positions. This way, you have a better angle to trim the vitreous base at 12 and 6 o’clock with a lower risk for lens touch.

Chandelier light at 4 o´clock

Diagram 4.1 Diagram of position of working ports, infusion line and chandelier light of a right eye. The corresponding picture is Fig. 3.2

Working port at 2 o´clock

Infusion port at 8 o´clock

Working port at 10 o´clock

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Pits & Pearls In patients with narrow lid margins (for example, children or Asian patients), ports that are placed too superiorly may ‘disappear’ under the upper eyelid. Constantly moving the eye inferiorly to expose the hidden ports and introduce your instruments can be extremely annoying during the surgery.

Pits & Pearls Every surgeon will tell you that you have to avoid the 3 and 9 o’clock position because of the ciliary arteries and the risk for haemorrhage. We found this to be a surprisingly rare event.

Pits & Pearls In revisional surgeries, try to identify the previous sclerotomy sites and avoid them. Reopening the previous sclerotomies may result in very irregular and leaking wounds.

Practical procedure (Figs. 4.2–4.6): One always starts with the infusion port inferotemporally. Take a cotton swab in one hand, a 3.5-mm scleral marker (pseudophakic eye) in the other hand, and place the cotton swab posterior (behind) to the limbus on the conjunctiva. Pull the conjunctiva a little to the side parallel to the limbus, mark the sclerotomy with the scleral marker, replace the scleral marker with the knife and perform a transconjunctival sclerotomy at an angle of about 15° parallel to the limbus. Usually, a minor bleeding highlights the sclerotomy site. Here, the trocar cannula with the blunt insertor is introduced. The first half of the insertion is 15° parallel to the limbus and the second half upright towards the middle of the eye (perpendicular). Finally, fixate the trocar cannula with the trocar forceps and remove the blunt insertor. Hold the infusion cannula with the trocar forceps (DORC, see materials) and insert the closed infusion line. Then ascertain whether the infusion cannula is located in the vitreous cavity: You turn the cannula with the trocar forceps in direction of the cornea until you can recognize with certainty the cannula’s location in the vitreous cavity. The infusion is only opened at the beginning of the vitrectomy. Then the other trocar cannulas are inserted 2:30 to 2 o’clock and at 9:30 to 10 o’clock with the same procedure. The procedure concerning the location of the infusion cannula in the vitreous cavity is very important as incorrect positioning of the infusion cannula can cause a

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Pars Plana Vitrectomy Step by Step

Diagram 4.2 Diagram of the anatomy of the pars plana (from outside to inside)

47 Sclera Subchoroidal space Choroid Pars plana epithelium Vitreous

number of complications, e.g. subchoroidal positioning can cause a choroidal detachment, subepithelial positioning can cause a detached pars plana and epithelium or subretinal positioning can lead to a detached retina (Diagram 4.2).

Pits & Pearls No. 8 Infusion cannula 1. Examination of the inner opening of the infusion cannula before starting the infusion is a must in each and every vitrectomy. Make sure that it is not blocked by ciliary epithelium or intraocular membranes. Opening the infusion whilst the opening is under the ciliary epithelium can within seconds turn a straightforward vitrectomy into a nightmare case. 2. When you can see that the opening is in the correct position but is blocked by blood or membranes, try to clear the opening with a sclerotomy knife, membrane pic or the vitreous cutter. Be careful not to touch the lens during this manoeuvre in phakic patients. In the case of doubt, remove the infusion port and try a different site for your infusion. 3. If you are still unsure whether your infusion port is in the right place, introduce the light pipe through the port. You should be able to confirm the correct position even through haemorrhages in the vitreous base. 4. In very complicated cases when you cannot examine the infusion port (trauma, endophthalmitis), start the vitrectomy with infusion connected to an anterior chamber maintainer. Clear the vitreous immediately behind the lens with a vitreous cutter introduced through the pars plana to clear the view. Then insert the infusion trocar via the pars plana as soon as you can see the vitreous base. Even in such complicated cases, do not open the infusion without confirming that the infusion cannula is in the correct position. 5. One of the potential dangers of small-gauge vitrectomy systems is that the infusion cannula is more mobile than with 20-gauge system (with the 20-gauge systems, the infusion port is usually secured with a scleral suture). A mobile infusion port can easily be angled or displaced during small-gauge vitrectomy. Secure a loop of the infusion tubing to the drape to avoid unintentional displacement of the infusion cannula.

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Pits & Pearls The trocars of some manufacturers are made of transparent plastic and are notoriously difficult to see with the usual action of indentation and illumination with a light pipe. If you are using one-step systems, you can usually see the metallic tip of the sclerotomy knife and the infusion port sitting on top of it when you indent the eye a little at the end of the introduction of the trocar/ knife combination.

2. Phacoemulsification DVD

Video 2 Combined Surgery: Phaco and PPV

You may insert the trocars before or after phacoemulsification. During phacoemulsification, the infusion is closed. Then the phaco is performed as usual. Regarding the size of your rhexis, it is important to ensure that the edge of the rhexis circularly covers the intraocular lens, as the IOL optic can easily dislocate during vitrectomy in front of the anterior capsule. Therefore, perform a smaller capsulorhexis (4–5 mm). Furthermore, it is advisable to polish the anterior capsule (anterior capsule polishing) to enable a clear view into the periphery. The IOL is usually inserted at the end of the phaco and before the vitrectomy. In difficult cases, some surgeons prefer to insert the IOL at the end of the PPV because the IOL edge disturbs the view into the periphery. After IOL implantation and irrigation and aspiration, hydrate the paracentesis and the tunnel well to ensure a stable anterior chamber during the vitrectomy. If the anterior chamber during vitrectomy is unstable, place a 10-0 nylon suture at the tunnel. This is particularly advisable if significant indentation is planned during the vitrectomy (for example, retinal detachment cases), as indentation may open the corneoscleral wound and displace the IOL. Note: In pseudophakic eyes, BSS is used as irrigation fluid and in phakic eyes BSS Plus®. BSS Plus also contains glutathione, glucose and sodium bicarbonate (see materials list).

Pits & Pearls Close the infusion during an anterior segment procedure.

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Pars Plana Vitrectomy Step by Step

Pits & Pearls In combined phaco and vitrectomy, opinions vary on when to introduce the trocars. Some surgeons prefer to perform a standard phaco on a ‘virgin’ eye without any previous manipulations. Other surgeons induce the trocars before starting the phaco. This has the advantages of avoiding possible chemosis following phaco, a soft eye or opening the corneal wound during trocar introduction. An additional advantage is the option of a limited core vitrectomy before the phaco in cases of vitreous haemorrhage in order to improve the red reflex for phaco surgery.

Pits & Pearls Perform phaco and vitrectomy only if you previously have gained considerable experience in performing phacos. This step of the surgery must be performed flawlessly. If you struggle with the phaco, the cornea is likely to opacify during surgery, making retinal manipulations later on extremely challenging. If you damage the bag or the zonules, you run the risk of tamponade prolapse into the anterior chamber.

Pits & Pearls If you are really running into trouble during the phaco with corneal oedema or damage to the lens in cases of elective surgery (macular hole, membrane peeling), think about delaying the vitrectomy part of the procedure until the situation has improved a couple of days later.

Pits & Pearls No. 9 Posterior capsular opacification: This should be removed if it reduces visibility. In addition, a YAG-laser capsulotomy is significantly more difficult in vitrectomized eyes. A PCO can be removed from pars plana with the vitreous cutter. Settings: approx. 500 cuts/min and normal vacuum. Cut a circular hole in the posterior capsule. The IOL cannot be injured by this procedure. A small central capsulotomy is sufficient. A larger capsulotomy is associated with the dangers of IOL dislocation and tamponade prolapse into the anterior chamber.

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Pits & Pearls No. 10 Blood in the anterior chamber: If you experience a bleeding during the PPV into the anterior chamber, you can either aspirate the blood with irrigation or aspiration instruments or inject a viscoelastic gel into the anterior chamber to push the blood to the edge of the anterior chamber and tamponade the bleeding. Ask the scrub nurse to remind you to remove the viscoelastic at the end of the vitrectomy. It is important to do this before you instal the tamponade, as the removed viscoelastic has to be replaced by fluid, which again will enter the posterior chamber and displace the tamponade.

Pits & Pearls No. 11 DVD

Video 3 Special techniques for the anterior chamber

Blood clots in the anterior chamber: If the bleeding has stopped, extract fibrous strands of blood with an Eckardt forceps through a paracentesis.

3. Focussing The surgeon or the scrub nurse flicks in the BIOM. Next, the light pipe is introduced in the temporal trocar towards the macula, until the pupil is bright. Then, the inverter is activated, the microscope light turned off and the image is focussed. For beginners, it may be frustrating to adjust the focus at the beginning of vitrectomy. However, if you keep a few rules in mind, you will find focussing easy. There are three adjustable parameters: (1) Focus wheel at the BIOM, (2) focus on foot pedal of the microscope, and (3) zoom on foot pedal of the microscope (Fig. 4.7). When focussing the image, you should only change the two parameters, focus wheel BIOM and focus foot pedal, and NOT the zoom. You should only change the zoom when you have a sharp image. Remember following steps 1. Minimal zoom. 2. Turn the BIOM-adjustment body with the focus wheel to the top position. 3. Move the microscope with the focus foot pedal so far down towards the cornea until you get a fairly big image (red pupil). 4. Turn the focus wheel (BIOM) until you get a sharp retinal image. If the image is sharp, move the microscope further down towards the cornea with the focus of the foot pedal (Cave: corneal touch!). Lastly, you can increase the zoom with the zoom pedal, but be aware that the resolution decreases the more zoom you have. If the image is totally blurred and you eventually cannot continue, or you changed the front lens, always return to the initial parameters (lowest zoom, BIOM adjustment body to the top).

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Fig. 4.7 A surgical microscope with attached BIOM. Integrated is an inverter, which may be operated manually or by foot pedal. At the front of the BIOM, the interchangeable front lenses are attached. The adjustment body can be adjusted with the focus wheel

Inverter

Adjustment body Focussing wheel Front lens

If you are using the EIBOS system, try to reach the manual focus with your right index or middle finger. Once you have mastered this, it makes focussing a lot easier than advising the scrub nurse in focussing up or down.

Pits & Pearls No. 12 Corneal lubrication: A major problem during vitrectomy, especially in combined surgeries with a duration of over 1 h, is corneal epithelial oedema. With the application of methylcellulose (Celoftal, Alcon) on the cornea, the cornea can remain clear for many hours. A debridement of the epithelium is rarely necessary, but if needed, use a broad blade (crescent knife).

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Pits & Pearls No. 13 Small pupil: If the pupil contracts during surgery, inject 0.01% Adrenalin into the anterior chamber. The pupil should enlarge within seconds. If the small pupil is caused by posterior synechiae, use stretching instruments such as a push-pull or insert iris hooks to enlarge the pupil.

Pits & Pearls No. 14 BIOM and air: If you perform a water against air exchange, the image will become blurred. You can focus the image by turning the focus wheel of the BIOM so that the front lens moves up. The image will become focussed again.

4. Core vitrectomy DVD

Video 4 Difficult PVD

Here, we start at with the core vitrectomy. In contrast to cataract surgery, you will be surprised by how much space you have in the vitreous cavity. In contrast to phacoemulsification where you hold the instruments almost horizontal, you hold the instruments during vitrectomy almost perpendicular (towards the optic nerve). The settings can be adjusted according to the individual preferences and the vitrectomy machine. For details, see Table 4.2. We usually start with the removal of the central vitreous (‘core vitrectomy’) in order to have enough vitreous body for the subsequent posterior vitreous detachment. It is also important to clear the vitreous immediately in front of your ports. Otherwise, there is the danger of pushing the vitreous base forward when introducing your instruments, thereby causing retinal breaks in the vitreous base. This is of particular importance when introducing blunt instruments, for example, a fluid needle or injection needle. Table 4.2 Approximate settings for 23-gauge with different vitrectomy machines Old generation vitrectomy New generation vitrectomy machines with 2,500 cuts/min machines with 5,000 cuts/min Core vitrectomy 1,500 400 3,000 300 PVD 0 400–600 0 400–600 Vitreous base/shaving 2,500 0–200 5,000 0–200 Removal of posterior 400 400 400 400 capsule Retinotomy 300 200 300 200 Cutting speed Vacuum mmHg Cutting speed Vacuum mmHg cuts/min cuts/min

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Pits & Pearls No. 15 Subepithelial location of infusion cannula: Even an initially correctly placed trocar cannula may move subepithelially during a later stage of the operation. If you experience a retinal or choroidal detachment, stop the infusion, remove the infusion line, and insert it in a safe trocar cannula. Re-open the infusion and the retina or choroid will reattach. Now check the location of the infusion cannula. Is it 3.5 mm posterior to the limbus? If not, replace the trocar cannula correctly. Is the trocar located subepithelially? If so, then free the trocar from the tissue with a membrane pic inserted in the opposite cannula.

5. Induction of posterior vitreous detachment For this step, we routinely use a 90D front lens. To induce a posterior vitreous detachment is a difficult procedure in the learning phase. We therefore recommend staining vitreous first with triamcinolone or trypan blue. The vitreous body is then much easier to identify and the induction of posterior vitreous detachment significantly easier. For induction of PVD, position the vitreous cutter just in front of the optic disc, then increase suction (foot pedal to bottom position) to a maximum. In the suction phase, the cortex and especially the posterior hyaloid will be engaged in the aspiration port. Then draw the vitreous cutter slowly with maximal suction towards the lens. If the manoeuvre is successful, you will see a kind of fine silk screen that moves forward together with the vitreous cutter. Sometimes, this whole manoeuvre must be repeated several times until it succeeds. Before you repeat the manoeuvre, cut the aspirated vitreous in the vitreous cutter to prevent traction and tractional tears and then place the vitreous cutter in front of the optic disc again.

Pits & Pearls No. 16 PVD 1. The correct assessment of the relationship between the posterior vitreous face and the retina/optic disc is one of the key steps to master pars plana vitrectomy. Always check if a PVD is present or not. Even in cases when you expect a PVD to be present (for example, retinal detachments), you will sometimes be surprised by an attached vitreous face. 2. The freshly detached posterior vitreous face has a ‘beaten metal’ appearance. You know that you have induced a PVD if you see this appear on the posterior surface of the vitreous. When a PVD is induced, suddenly, a lot more vitreous, which must be removed, will appear in the vitreous cavity.

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Pits & Pearls No. 17 PVD and dye 1. We recommend beginners to stain the vitreous at the beginning of vitrectomy for the first 10–20 vitrectomies. The vitreous is much easier to recognize and vitrectomy and especially the induction of a posterior vitreous detachment become considerably easier. 2. To stain the posterior vitreous face with triamcinolone: Perform a core vitrectomy and a peripheral vitrectomy in front of your ports. Induce the cannula into the mid-vitreous (be careful not to inject peripherally, or you will inject in to the vitreous base and exert traction). Inject a small amount of triamcinolone that will drop down onto the posterior pole. This will very nicely stain the bursa praemacularis of the vitreous. Do not inject too much triamcinolone for vitreous staining. It will only obscure your view and will be cumbersome to remove later on during the surgery. Few drops are sufficient for staining the posterior vitreous. 3. Once the bursa praemacularis is stained with triamcinolone, try to engage the posterior vitreous face at the optic disc. Try to cut a small break in the posterior vitreous face nasal to the disc, then ‘pick up’ the posterior vitreous phase with the cutter and suction only. Pull anterior towards the lens. Try to keep an eye on the advancing posterior vitreous face in the midperiphery. This looks like a tidal wave. It is where breaks will develop during induction of a PVD.

Pits & Pearls No 18 PVD and myopic eyes: Beware of highly myopic eyes. They often have a ‘vitreoschisis’. You may think that there is a complete PVD, yet, there only is a vitreoschisis with the posterior vitreous face still attached to the retina. In the case of doubt, stain with triamcinolone. The remnant vitreous face will appear as a thin membrane-like structure on the retina. Sometimes you can peel it off with the forceps; sometimes you have to use the fluid needle to brush it of the retina.

Pits & Pearls No. 19 Difficult PVD: If you are not able to induce a PVD, try the following: (1) increase the vacuum to 600 mmHg and try again, (2) stain the vitreous with trypan blue or triamcinolone and try again, (3) insert a 90D lens and mobilize the central vitreous or even better, the posterior hyaloid membrane with an Eckardt forceps. If you have mobilized a larger piece or created a hole, try to aspirate this part with a vitreous cutter and provoke a PVD.

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Fig. 4.8 Drawing of the anatomical relationships in the anterior eye (Hogan et al. 1971). (1) ora serrata (termination of the retina), (2) insertion of vitreous base stretches 4 mm posteriorly over the retina and 2 mm anteriorly over the ciliary body, (3) posterior hyaloid, (4) anterior hyaloid, (5)hyaloid fossa and Berger space 4. 1.

5. 2. 3.

6. Trimming of vitreous base After successful PVD, continue with trimming of the vitreous base (Fig. 4.8). We usually use a 120D or comparable wide-angle lens. Regarding the settings of the vitrectomy machine, decrease the vacuum and increase the cutting frequency the closer you work with the vitrector at the retina (Table 4.2). When performing vitrectomy, hold the instruments almost vertically towards the orbital apex. Make calm and slow movements, in contrast to irrigation/aspiration during phaco. Another important difference is that you hardly move the irrigation handpiece during phaco, but the light pipe in PPV is in constant motion. Light pipe and vitreous cutter move simultaneously, the light pipe illuminating the path of the vitreous cutter. You point the beam of the light pipe to the tip of the vitreous cutter. The vitreous is often difficult to detect. You recognize the vitreous best in the light cone. Move both instruments in a half circle in the vitreous cavity as if peeling an onion from inside to outside. In pseudophakic eyes, the nasal vitreous is cut with the vitrector from the temporal trocar and the temporal vitreous is removed from the nasal trocar. One should always remember that the eye is a sphere. This means that you have little space behind the lens but plenty of room in the middle of the eye. Coming closer to the posterior pole, you can estimate the vicinity to the retina by looking at the shadow of the vitreous cutter. Be aware: The retina forgives no mistakes, and retinal breaks are easily made. Be cautious, if you come close to the retina with the vitreous cutter. In phakic eyes, you can cross the midline only when working at the posterior pole to mid-periphery. To reach the vitreous base, you are not allowed to cross the midline. The vitreous base can be removed from the opposite site by indenting the vitreous base or from the same side with the ‘backhand’ and wide-angle viewing systems. In detachment surgery, the vitreous base must be removed as completely as possible because vitreous traction is causatively responsible for the retinal break and residual vitreous may continue to exert traction on the retina and cause postoperative

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new breaks. For surgeries such as macular hole or macular epiretinal membranes, it is not necessary to remove the vitreous base completely because the pathological changes are located here in the macula and not in the retinal periphery. In contrast, working too aggressively in this area may cause more harm by inducing retinal breaks or lens touch. The presence of the natural lens makes working in the area of the vitreous base challenging. Firstly, there is a risk of lens touch, and secondly, access to the vitreous base is more difficult as the lens is in the way, in particular in elderly patients with a thicker lens. Finally, a vitrectomy will induce cataract development in each and every case of phakic patients.

Pits & Pearls Working in the area of the vitreous base and trimming the vitreous base is another key step to learn if you want to master vitrectomy. Numerous techniques can be used. Our favourite techniques are (US) using a chandelier light and indentation with a scleral depressor and (HH) scleral indentation with a light pipe or working with your ‘backhand’ with the vitreous cutter facing the retina on the side of your vitreous cutter using wide-angle viewing systems. This avoids indentation and is used mainly for trimming the vitreous base during macular surgery.

Pits & Pearls No. 20 Scleral folds or soft globe during vitrectomy: If you view scleral folds during vitrectomy or if the globe is soft, then stop PPV at once. The most likely cause is a dislocated infusion line. Reinsert the infusion line and check if the globe is normotensive and if the scleral folds have vanished.

7. Anterior vitrectomy As beginner, it is amazing to learn how much vitreous is present in the eye (Fig. 4.8). Even after a thorough peripheral vitrectomy, a lot of vitreous remains behind the lens. This can be noticed intraoperatively when air bubbles are trapped in the vitreous behind the lens capsule. These air bubbles cannot be removed with the fluid needle but only by removing the vitreous behind the lens capsule. An anterior vitrectomy is easy in pseudophakic patients; in phakic patients, it is dangerous because the location of the posterior capsule is difficult to determine. Therefore, injury to the posterior capsule is a common beginner’s mistake. This happens less often when using trocar cannulas, as they limit your movements towards the capsule.

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Hold the vitreous cutter behind the intraocular lens and remove the vitreous by moving the vitreous cutter along the edge of the IOL. Hold the aspiration port of the vitreous cutter towards 12 o’clock and then 6 o’clock in order to avoid injuring the posterior capsule.

Pits & Pearls No. 21 Lens touch 1. A lens touch is often caused by the light pipe (focussing the light beam on peripheral vitreous during trimming of the vitreous base) or the endolaser probe when performing peripheral laser on the opposite site. One focusses on the opening of your vitreous cutter but ‘forgets’ the other intraocular instrument. It has to become second nature to hold the second instrument in the correct position without thinking about it. 2. Another common cause of lens touch is pushing the infusion port into the lens during indentation. Avoid by taking extra care in this area and indent pushing the vitreous base towards the centre of the eye, not anteriorly towards the lens. 3. If you notice a lens touch during or at the end of your surgery, clearly mark it in your surgical notes. It is important to know this if you are planning to perform the phaco at a later stage, as this weakens the posterior capsule. We have seen an entire lens dropping onto the posterior pole during hydrodissection; the posterior capsule split at the site of the previous lens touch and the lens dropped posteriorly.

8. Internal search for retinal breaks At the end of vitrectomy, breaks must be identified and treated accordingly. Inspect the entire peripheral retina with the aid of a scleral depressor. If a break is present, you must remove any residual vitreous adhesions, treat the break with laser -or cryoretinopexy, and a gas tamponade needs to be installed, for example, with 20% SF6. Otherwise, a postoperative retinal detachment occurs.

Pits & Pearls No. 22 Internal search for retinal breaks 1. Perform an internal search in each and every case of vitrectomy, even in low-risk cases. Perform the search at the very end of your procedure, as even minor intraocular manipulations may create breaks in the area of the vitreous base that may not be noticed if you have performed your inspection of the vitreous base beforehand.

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2. Do not be complacent when performing the internal search. Identification of potential problems in the retinal periphery is one of the key steps to lower your complication rate. Make sure that you visualize the entire retinal periphery 360° up to the ora serrata. Move your scleral depressor constantly when inspecting the vitreous base. This is a dynamic procedure. This way you will identify breaks opening up during your indentation that you may miss if the indentation is too ‘static’.

9. Laser photocoagulation of peripheral breaks If the break is so peripheral that you need a scleral depressor to see it, you must now either insert a chandelier light in order to have a free hand for the scleral depressor, or you use a combined laser with optical fibre (see instruments) or indent the eye with your light pipe. Surround the break with one to three rows of laser burns (e.g. using the 532-nm diode laser OcuLight GL Company Iridex, we use the laser parameters: power 150 mW; duration, 200 ms; interval, 300 ms).

Pits & Pearls No. 23 Iatrogenic break: When a small break is located within the vascular arcades, a laser treatment is not necessary as the pigment epithelium in the central area has sufficient pumping function so that no detachment occurs. If the break is large, however, we recommend lasering the break with one row of laser burns. Even if you create a peripheral break, this is not a problem as long as you also recognize the break. Surround the tear with three rows of laser burns, and perform a gas tamponade.

Pits & Pearls No. 24 Laser therapy 1. A laser treatment can be carried out in a water-filled (BSS-filled), silicone oil–filled and PFCL-filled eye. In an air-filled eye, it is difficult to laser due to a poor visibility. 2. It is easiest to laser breaks under heavy liquid, as you have a good apposition of retina and retinal pigment epithelium. One of the disadvantages of this technique is that the margins of the break are more difficult to see. Mark the location of breaks with endodiathermy or laser spots before covering it with heavy liquid. This way it is easy to identify them under heavy liquid.

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3. Beware of the ‘continuous’ function of the laser. You can easily overtreat. This may result in mini-explosions, choroidal haemorrhage, retinal breaks or predispose to postoperative tears. Pigmentation increases towards the periphery. Less energy is needed for peripheral laser spots. 4. The further you move the laser probe away from the retina, the larger the resulting spot size on the retina (and the more energy you need to create a burn). This can be quite useful if you want to treat larger areas as the resulting burns have softer edges and do not cut the retina like a knife. 5. Use 360° prophylactic laser with caution. It may not be necessary, may result in anterior segment ischemia and will make it very difficult to identify small breaks in cases of postoperative retinal detachments.

10. Cryotherapy of peripheral break The cryotherapy of a peripheral break is a good alternative to laser photocoagulation, in particular in phakic eye where endolaser of breaks in the retinal periphery without touching the lens is challenging. You indent the retina with the cryo-probe and hold the light pipe in the other hand. Cryotherapy should be applied sparingly, preferably with one cryo-effect in the middle of the break in order to reduce the risk for PVR.

Pits & Pearls No. 25 Cryotherapy: When performing cryotherapy for retinal breaks, a lot less cryo is needed if the vitreous cavity is filled with air.

Pits & Pearls No. 26 Cyclocryotherapy: When we perform cryotherapy of the ciliary body, we treat three quadrants (the superonasal quadrant remains untreated). The cryo-probe is applied approximately 2–3 mm posterior to the limbus so that the freezing effect reaches the limbus. We apply 3–4 freezings per quadrant; duration: 50 s. The cryotherapy of the retina for ischemic retinopathy should, if possible, be performed with an indirect ophthalmoscope. You can freeze until a strong white colouring occurs. In the absence of a good field of vision, we freeze for 10 s.

11. Intraoperative tamponade Intraoperative tamponades have several indications. A fluid/air (fluid against air) exchange may be necessary before injecting a dye (e.g. Brilliant Blue G). Further, a

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fluid/air exchange is an important step in detachment surgery. A PFCL (heavy liquid) tamponade is important in detachment surgery to attach the retina. PFCL must always be completely removed because it damages the retina. Air tamponade (exchange of water against air) To perform an air tamponade, you hold the fluid needle in front of the optic disc of the water-filled (BSS-filled) eye. The scrub nurse switches from water to air. The air streams anteriorly in the eye, and the water is aspirated by holding the tip of the fluid needle in the water. During air insufflation, the visibility worsens, as air has a different refractive index to water. This problem can be solved by turning the front lens of the BIOM with the focus wheel up a little bit until the image is sharp. After a while, you recognize a water level at the posterior pole. You continue to hold the fluid needle in front of the optic disc and aspirate the remaining water. If in doubt, it is better to leave a little water at the posterior pole than to risk a retinal or optic disc touch. Water tamponade (exchange of air against water) Hold the fluid needle directly behind the IOL. Then the scrub nurse switches from air to water, and the eye fills up quickly with water. If small air bubbles remain at the end behind the IOL, then there is still (anterior) vitreous behind the IOL. If you plan to perform now macular surgery, you have to remove these irritating air bubbles. In order to do so, perform an anterior vitrectomy. PFCL tamponade (exchange of fluid against PFCL) Inject PFCL preferably in a fluid-filled eye and not in an air-filled eye. The PFCL must be injected slowly. PFCL injected too quickly can induce retinal damage. PFCL should never be injected in direction of the macula. You start with the injection nasal to the optic disc and then move the cannula slowly towards the lens leaving the tip of the cannula in the PFCL bubble. Leaving the tip of the cannula in the big bubble prevents the formation of small PFCL bubbles (fish eggs). When injecting PFCL, simultaneously decompress the globe with a fluid needle. Alternatively, you can use a dual-bore cannula (Fig. 2.25) which allows simultaneous injection and decompression.

Pits & Pearls Try to inject one bubble only. Start very slowly, and then always keep the tip of your cannula in touch with the bubble. This avoids splitting the stream into multiple bubbles, which can then displace into the subretinal space.

Removal of PFCL Hold the fluid needle in front of the optic disc and aspirate the complete PFCL bubble. If a small bubble remains and you do not succeed with the fluid needle, then do not insist but aspirate the residual bubble with a silicone-tip fluid needle in order not to damage the retina or the optic disc.

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12. Postoperative tamponade Important: The performance of a tamponade depends very much if you use a trocar system with valves or without valves. This is especially important for a silicone oil tamponade. If you use a trocar system with valves and inject too much silicone oil, you can create a dangerous excess pressure that can lead to the occlusion of the central retinal artery. In case of water or gas, you can easily release excess pressure with the fluid needle. This is not possible with silicone oil. You must therefore learn to control a possible hypertension. DORC’s trocar system has the advantage that the valve can be removed in case of high intraocular pressure (Fig. 5.2). This is not possible for other manufacturers (Alcon (Fig. 2.3b), Oertli, Geuder). Alcon includes a metal cannula in the trocar valve pack, which is inserted into the valve trocar in order to release excess pressure. An intraocular hypertension cannot arise with a trocar system without valves (Fig. 2.4). Here you must deal with a possible hypotension.

Pits & Pearls No. 27 Anterior segment and tamponade 1. Make sure that all potential anterior segment problems are addressed before starting a fluid/air exchange. The air bubble will push the iris-lens diaphragm forward, making any manipulations in the anterior chamber extremely difficult. In addition, fluid injected into the anterior chamber will enter the posterior segment and displace the tamponade, potentially causing an ‘underfill’. 2. In cases of large defects within the zonules or the lens capsule, inject miochol and an air bubble into the anterior chamber before fluid–air exchange. This prevents the iris-lens diaphragm from moving forward and avoids iris capture or displacement of the gas tamponade into the anterior chamber. With modern viewing systems and air in the anterior chamber, there usually is a sufficient view of the posterior pole to perform a safe fluid–air exchange.

Air tamponade (exchange of water against air) Remark: An air tamponade has several indications: (1) Air in the vitreous cavity presses against the edges of the sclerotomy incision and thereby stabilizes the sclerotomies, which results in a reduced postoperative hypotony. (2) Reduces postoperative bleeding (favourable for diabetic eyes) (3) tamponade for macular holes. (4) reduces the risk of an endophthalmitis. Gas tamponade (exchange of air against gas) After the fluid/air exchange, you can swing out the BIOM, activate the inverter, and switch on the light of the microscope. The surgical nurse attaches a 50-ml syringe with diluted gas to the three-way tap and injects the gas (about 45 ml) into the vitreous cavity (Fig. 4.9a, b). Instruct the scrub nurse to stop injecting immediately if he or she feels an increasing resistance to injection. To avoid an increased pressure in the eye, you must simultaneously decompress the eye. This can be achieved by holding the fluid needle behind the lens and leaving the side opening

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Fig. 4.9 (a) Exchange of air against gas in a 4-port vitrectomy. Note that the gas is injected through the infusion trocar on the left. (b) Exchange of air against gas in a 4-port vitrectomy. The gas streams onto the posterior pole, and the air is relieved with a fluid needle from the instrument trocar

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half open (just enough that the eye remains normotensive). Leave approximately 5 ml of gas in the syringe. Now stop the gas insufflation, and remove both instrument trocar cannulas. Before removing the infusion cannula, check whether the eye is hypotensive. In this case, inject gas to achieve normotension and then remove the infusion cannula. Light silicone oil tamponade Silicone oil tamponades can be used with 23-gauge technology. It is straightforward to use 1,000-cSt silicone oil. Some surgeons also use 5,000-cSt silicone oil with 23-gauge systems; however, we encountered several problems using this. If you are planning to use 5,000-cSt silicone oil for long-term tamponades, we would

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recommend enlarging one of the ports to 20-gauge. You can inject the oil into a water-filled or an air-filled eye. An injection into a water-filled eye is difficult because the two liquids are difficult to distinguish. We, therefore, recommend the exchange of air against silicone oil for most routine cases. Heavy silicone oil tamponade Since Oxane Hd® and Densiron 68® consist partially of PFCL, they should not come in contact with pure PFCL for longer periods of time. However, a short contact (for example, during direct PFCL–heavy silicone oil exchange) is possible. We, therefore, recommend the exchange of air against silicone oil for all straightforward cases. Exchange of air against silicone oil (light and heavy) The infusion line must remain in place because the air streaming in keeps the eye normotensive. Reduce the infusion pressure of air to 10–20 mmHg (Fig. 4.10a, b). a n

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Fig. 4.10 (a) Exchange of air against silicone oil in a 4-port vitrectomy. Pay attention that the infusion of air is switched on in order to have pressure in the eye but reduced to 10 mmHg in order to avoid hypertension. (b) Exchange of air with silicone oil in a 4-port vitrectomy with valve trocars. Just before the last air bubble vanishes, reduce the air pressure to 0 mmHg. If you are working with 3-port vitrectomy and therefore without a fluid needle, then remove the valves of the instrument trocars to allow the air to escape. (c) If the final air bubble vanishes behind the IOL, stop the infusion of air

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Fig. 4.10 (continued)

Intraoperatively

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Diagram 4.3 Diagram of the location of liquids at an air/silicone oil exchange

We use a silicone oil 23-gauge plastic cannula (Med One, DORC) which fits into a 23-gauge trocar. The oil falls from the anterior onto the posterior pole, i.e. the eye is filled from the back to the front with oil. At the same time, you must drain the air with a fluid needle from a trocar. When the last bubble disappears behind the lens (Fig. 4.10c), stop the infusion of air and remove the residual air bubble. Then inject so much silicone oil until the globe is hypo- till normotensive. During this procedure, check for a positive venous pulse. The sclerotomies should be sutured because otherwise silicone oil can flow under the conjunctiva. In aphakia, one needs an Ando-iridectomy: Before you inject the oil, cut a break with the vitreous cutter (low cut rate: about 200 cuts/min) in the peripheral iris at 6 o’clock (conventional oils) or 12 0´clock (heavy oils). The Diagram 4.3 shows the location of the fluids in the vitreous chamber during an air/silicone oil exchange. Air is lighter than silicone oil. During surgery, the silicone oil is injected into the air-filled vitreous cavity. Depending on the amount of injected oil, more or less water will be localized at the inferior pole after surgery. Exchange of PFCL against silicone oil (light and heavy) Exchange of PFCL to silicone oil is a common procedure. Remove the infusion line, fasten it to the silicone oil–filled syringe and reattach the infusion line to the infusion trocar. Inject the silicone oil with active injection modus into the vitreous

Pars Plana Vitrectomy Step by Step

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Fig. 4.11 (a) Exchange of PFCL against silicone oil in a 4-port vitrectomy. Be aware that the silicone oil is injected through the infusion trocar. (b) Exchange of PFCL against silicone oil in a 4-port vitrectomy. Hold the tip of the fluid needle in the PFCL phase and inject simultaneously oil with the foot pedal into the vitreous cavity

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cavity (Fig. 4.11a, b). At the same time, you hold the fluid needle in the PFCL phase. At the end of the aspiration, you see clearly the PFCL meniscus/bubble. Check the pressure of the eye a few times with your index finger. If the pressure has increased, stop the injection of oil and aspirate more PFCL. If the globe is hard (no venous pulse), remove a valve at once and let excess silicone oil flow out.

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Pits & Pearls No. 28 PFCL against silicone oil exchange 1. If unsure whether there still is some heavy liquid left behind, pause and wait. The heavy liquid will collect and the interface will be clearly visible after 15–20 s. 2. Removing the final puddle of heavy liquid is not an easy step. The danger is to aspirate retina into the fluid needle at the posterior pole or to damage the optic disc. Either try to remove the final bubble ‘in one go’ or let it collect over the optic disc. Then increase the pressure with the silicone oil injection and touch the bubble with the opening of the fluid needle. For small remnant bubbles, indent the eye with your ring finger. This will give you a much better pressure control than the injection of silicone oil with the foot pedal. Aspirate the heavy liquid bubble and immediately cover the opening of your fluid needle before withdrawing it from the eye, otherwise the heavy liquid bubble will drop back onto the posterior pole.

Pits & Pearls No. 29 Silicone oil injection: If you have no silicone oil 23-gauge cannula in place, take a second infusion line instead. Attach the oil-filled syringe to a second infusion line, and insert it in the nasal trocar cannula. Then you inject the silicone oil (active injection modus) into the air-filled eye. Make sure that the opening points towards the centre of the eye. If the opening points forward towards the lens, this may push silicone oil through the zonules into the anterior chamber.

Pits & Pearls No. 30 Methylcellulose in anterior chamber: If zonular lysis is present and oil flows into the anterior chamber, you can aspirate the oil with irrigation and aspiration. Inject methylcellulose (not viscoelastics) into the anterior chamber and leave it there postoperatively. The IOP will not increase after surgery. This procedure works only in a silicone oil–filled eye; it does not work in a gasfilled eye.

13. Removal of the trocar cannulas It is useful to remove the trocars in the following order: first the instrument trocars, then the chandelier light, and finally the infusion cannula. The infusion cannula

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Pars Plana Vitrectomy Step by Step

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remains in place until the end to avoid hypotension when removing the trocars. The infusion should therefore remain open until removal of the infusion cannulas. To remove the trocars, pull out the trocar with the trocar forceps, then press the edges of the sclerotomy together with a forceps and massage the sclerotomy with a cotton swab. Lastly, the infusion cannula is removed. Before you do this, check the intraocular pressure manually. If it is hypotensive, refill the eye with gas until the eye is normotensive. Then the infusion cannula with running infusion (BSS, air or oil) is removed. The sclerotomies are usually not sutured. Exceptions are silicone oil tamponades because the oil may cause subconjunctival cysts. A major advantage of not suturing a gas-filled eye is that the eyes are rarely hypertensive, as the expanding gas can escape postoperatively through the nonsutured sclerotomies. If you observe uveal tissue or even a vitreous prolapse out of the sclerotomy, you should remove it with the vitreous cutter because otherwise there is a possible wicking and endophthalmitis risk. If the sclerotomy is still leaking, it should be closed with a suture. The sclerotomy should be covered by conjunctiva; otherwise, it is recommended that the sclerotomy be sutured.

Pits & Pearls No. 31 Sclerotomy 1. For beginners, we recommend opening the conjunctiva in the area of the sclerotomies in order to recognize the sclerotomies clearly. This is particularly important if you want to suture the sclerotomy at the end of the procedure. 2. In the case of doubt, suture the sclerotomy. The potential disadvantages of a leaking sclerotomy outweigh the discomfort of a single suture. 3. To displace a vitreous wick, inject fluid (BSS, antibiotic solution) into the conjunctival stroma adjacent to the wick. The conjunctiva will balloon and the vitreous wick will retract. Alternatively, remove the vitreous wick with the vitreous cutter.

14. Sclerotomy sutures A 23-gauge sclerotomy can be sutured with an 8-0 Vicryl suture and a 20-gauge sclerotomy with a Vicryl 8-0 cross suture. To suture a sclerotomy is harder than you assume. Grasp one edge of the sclerotomy with surgical forceps, move the needle through the sclerotomy edge, then grasp the opposite edge of the sclerotomy with the forceps and pull the needle through the second edge. Test with the swab whether the sclerotomy is closed. If it still leaks, remove the suture and place a new suture.

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Pits & Pearls No. 32 Leaking sclerotomies 1. A leak can be identified by a chemotic conjunctiva above the sclerotomy in a fluid-filled eye or by air bubbles in an air-filled eye. If the sclerotomies leak, then place a Vicryl 8-0 on the sclerotomy (Fig. 4.12a, b). 2. These can occur after multiple vitrectomies and a large opening, for example, for silicone oil removal or if multiple sclerotomies have been placed in the same location. It is not uncommon in high myopes with a thin sclera. To close these large sclerotomies, do not use multiple single sutures (they make it worse) or large sutures (the larger needles may cause additional holes in the sclera). Use a 7-0 or 8-0 Vicryl single cross suture over the sclerotomy. Stay very superficially within the sclera and do not go ‘deep’. Use a long intrascleral path. Finally, use 4 instead of 3 throws for your first knot and ask the scrub nurse to close the infusion temporarily while you tighten the knot.

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Fig. 4.12 (a) Leakage of air from a sclerotomy in an eye with air tamponade. In this case, the sclerotomy should be sutured. (b) After suturing the sclerotomy with a Vicryl 8-0 single suture, the sclerotomy is closed airtight

References

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References Hogan MJ, Alvaredo JA, Weddell E (1971) Histology of the human eye. WB Saunders Company, Philadelphia, p 612 Lemley CA, Han DP (2007) An age-based method for planning sclerotomy placement during paediatric vitrectomy: a 12-year experience. Trans Am Ophthalmol Soc 105:86–89

Conventional Vitrectomy with 3-Port Trocar Setup

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In this chapter, the surgeries for particular indications and with increasing levels of complexity are explained in detail. The surgeries are performed in monomanual technique. Silicone oil removal and vitreous haemorrhage without complex retinal diseases are ideal procedures for beginners, in particular in pseudophakic patients. In silicone oil removal, you learn to handle the trocars, focus the retina with the BIOM and understand the basic functions of the vitrectomy machine. In vitreous haemorrhage, you work with the vitreous cutter and learn to remove the vitreous base. Macular surgery is more advanced. The major steps to master here are the induction of a PVD and an atraumatic removal of the membrane.

5.1

Silicone Oil, Densiron 68® and Oxane Hd® Removal

DVD

Video 5 Silicone oil removal

Traditionally, removal of silicone oil has been the first procedure to be performed independently when you make your first steps into the field of vitreoretinal surgery. This is because, in most cases, no major intraocular manipulations are performed, but a ‘proper’ 3-port setup is required and can be practised. In addition, most patients will be pseudophakic, so you do not have to fear a lens touch. And finally, this procedure can be rather boring for advanced surgeons, so they are more than willing to let beginners do these cases. The result is that the importance and the difficulty of the procedure are often underestimated. Silicone oil removal is an ideal opportunity to learn and to deal with the trocar cannulas and get a feeling for the posterior segment of the eye. We always perform silicone oil removal with the BIOM because we remove emulsified oil bubbles through a fluid–air exchange, and perform additional intraocular manipulations if necessary.

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_5, © Springer-Verlag Berlin Heidelberg 2012

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Pits & Pearls Remember that about 10–20% of patients undergoing silicone oil removal will need additional surgery at a later stage, e.g. for retinal redetachment or recurrent vitreous haemorrhage. The silicone oil removal procedure is an ideal opportunity to deal with any lesser or larger problems during the surgery. Therefore, perform a careful examination preoperatively for appropriate planning of the surgical steps. Try to identify epiretinal membranes, which are a lot more difficult to see when silicone oil is still in situ. Be always prepared that additional vitreoretinal manipulations or even a ‘silicone oil exchange’ may be necessary.

Pits & Pearls In particular, in units in which various silicone oils are used, always verify which type of silicone oil has to be removed. The setup to remove 1,000-cSt, 5,000-cSt or heavy silicone oil is different but they all look the same when performing fundoscopy. You can run into serious trouble if you think you are removing normal silicone oil but in fact it is heavy oil in situ and vice versa. Light silicone oils are easy to remove as they float on water. Heavy silicone oils are rather more difficult to remove because they are heavier than water.

Pits & Pearls No. 33 The surgical time to remove silicone oils depends on (1) the viscosity of the oil (1,000-cSt silicone oil < 1400 cSt Densiron 68® < 3,500-cSt Oxane Hd® < 5,000-cSt silicone oil) and (2) the size and length of the extraction cannula. The higher the viscosity, the bigger sized cannulas you should choose. A 23-gauge cannula is fine for 1,000-cSt silicone oil or for 1,400-cSt Densiron 68® but not for 5,000-cSt silicone oil. For 5,000-cSt silicone oil or for 3,400cSt Oxane Hd®, use a 19-gauge or even a 16-gauge cannula.

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Silicone Oil, Densiron 68® and Oxane Hd® Removal

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Fig. 5.1 Passive silicone oil removal: Both valves were removed. Now the silicone oil flows out passively. This surgical method takes longer than the active silicone oil removal. Remark: Heavy silicone oil cannot be removed with this method as it is heavier than water and therefore lies on the posterior pole

Instruments 1. 3-port trocar (20-gauge or 23-gauge), 120D lens 2. Silicone oil 1,000 cSt: Active aspiration with 23-gauge plastic cannula (Medon or DORC) or 19-gauge metal cannula (Alcon) Silicone oil 5000 cSt: 16-gauge cannula (Beaver-Visitec, UK, see material) with 10-ml syringe or 19-gauge metal cannula (Alcon) with silicone oil extraction set Oxane Hd® and Densiron 68®: 19-gauge metal cannula (Alcon) 3. Fluid needle 4. Scleral depressor Possible tamponade Air or gas Individual steps 1. 3-port system 2. Passive or active silicone oil removal (Remark: Heavy silicone oils can only be removed actively) 3. Water/air exchange: aspiration of silicone oil bubbles from the water meniscus 4. Internal search 5. Removal of trocars 1. 3-port system 2. Passive or active silicone oil removal Passive removal of light silicone oil: This method is time consuming but avoids strong aspiration, which might lead to a suprachoroidal haemorrhage. Insert three 23-gauge trocars. Remove the valves of both instrument trocar cannulas, open the infusion and let the oil evacuate passively (Fig. 5.1). The eye must be positioned so that the silicone oil flows in the direction of the open trocar cannulas (Fig. 5.2).

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Fig. 5.2 The passive silicone oil removal is almost done. You see the meniscus of the oil bubble in the pupil. By rotating the globe up with the help of the trocar forceps, you can remove the residual oil

Fig. 5.3 Active silicone oil removal: With a 23-gauge plastic cannula, which fits in a trocar cannula, you can aspirate the silicone oil. This plastic cannula is fixed to a syringe, which is attached to the pump in the vitrectomy machine. DORC. 1272.VFI06

Active removal of light silicone oil: All methods are performed under BIOM view. 1. 1,000-cSt silicone oil: Insert three 23-gauge trocars. Aspirate the silicone oil with a syringe attached to a 23-gauge cannula (active aspiration mode) (Figs. 5.3 and 2.29). When extracting the silicone oil, make sure that the tip of the aspiration cannula is always located in the silicone oil bubble and not in the water phase (Fig. 5.4). 2. 1,000- and 5,000-cSt silicone oils: Open the conjunctiva superotemporally, perform a perpendicular 19-gauge sclerotomy and aspirate actively with the 19-gauge metal cannula (Figs. 5.5 and 5.6). 3. 5,000-cSt silicone oil: Perform an enlarged 20-gauge sclerotomy and aspirate manually with a 16-gauge cannula attached to a 10-ml syringe. 4. 1,000- and 5,000-cSt silicone oils: Silicone oil removal with the Constellation vitrectomy machine is simple and fast. Attach the adapter with syringe (silicone oil removal set, Alcon) to a valveless 23-gauge trocar and aspirate actively the silicone oil (Fig. 5.7). The removal time is approximately 1 min.

5.1

Silicone Oil, Densiron 68® and Oxane Hd® Removal

Fig. 5.4 Active silicone oil removal: On the right side, you see the yellow cannula. The water phase is located in the back (retina), and the silicone oil phase is located in the front (lens)

Fig. 5.5 Active (heavy) silicone oil removal: A superotemporal sclerotomy was created for the 19G suction cannula (Alcon). The silicone oil syringe is connected to the vitrectomy machine. Afterwards, a fluid/ air exchange is performed

Fig. 5.6 One recognizes the meniscus of heavy silicone oil on the metal cannula. The posterior phase is heavy silicone oil, and the anterior phase is water

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Fig. 5.7 Silicone oil removal with the Alcon silicone oil removal set and the Constellation vitrectomy machine. The removal time for light and heavy silicone oils is 1–2 min

Active removal of heavy silicone oil (e.g. Oxane Hd® or Densiron 68®) Densiron 68® is heavier than Oxane Hd® (see density, Table 2.1) but has a viscosity comparable to 1,000-cSt silicone oil and is therefore easier to remove than Oxane Hd®. 1. Oxane Hd® or Densiron 68®: Use the 19-gauge metal cannula from Alcon and active extraction modus (Figs. 5.5 and 5.6). Pull the residual heavy oil bubble upwards to the centre of the vitreous cavity and remove it safely here. 2. Oxane Hd® or Densiron 68®: Removal of heavy silicone oils with the Constellation vitrectomy machine is also simple and fast. Attach the adapter to a valveless 23-gauge trocar and aspirate actively the silicone oil (Fig. 5.7). The removal time is approximately 2 min. 3. Densiron 68®: An alternative method is to remove Densiron 68® through a conventional 23-gauge trocar system using a short 23-gauge cannula (MedOne, DORC). Remove the silicone oil bubble as one would with conventional silicone oil, always staying in touch with the bubble with active suction. The residual bubble will stay connected to the short cannula through the ‘siphoning’ effect and will move upwards towards the cannula and can easily be removed this way. Small remnant bubbles at the posterior pole can then be collected with the fluid needle (Romano et al. 2009).

Pits & Pearls No. 34 When removing Densiron 68® through a 23-gauge trocar system, it is important not to lose contact with the bubble before it starts ‘floating up’ towards the cannula. In order to guarantee uninterrupted suction, check the residual volume that is left to be aspirated in your suction line just before you are about to ‘pick up’ the residual bubble. If only a few millilitres are left in your syringe, remove the oil from the syringe by switching to injection mode outside the

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Silicone Oil, Densiron 68® and Oxane Hd® Removal

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Fig. 5.8 After passive or active silicone oil removal, a fluid/air exchange is performed. This procedure is repeated approximately three times with help of the BIOM in order to remove the residual oil bubbles and the emulsified silicone oil bubbles. Hold the tip of the fluid needle onto the meniscus in order to aspirate the floating oil bubbles

eye, then go back in to remove the residual bubble with uninterrupted suction. If you lose contact with the bubble and it is too small to be reached with the short cannula, you either need to proceed with a long 23-gauge cannula (which takes a long time) or switch to the method using the 19-gauge cannula outlined above.

3. Water/air exchange: aspiration of silicone oil bubbles from the water meniscus Then perform a water–air exchange through the BIOM. Take the fluid needle and try to ‘fish’ residual oil from the water surface at the water/air interface (meniscus). The water–air exchange should be performed approximately three times (Figs. 5.8 and 5.9). If there is a bigger residual oil bubble, it will be time consuming to remove it with the fluid needle. In this case, attach the fluid needle to active aspiration (Fig. 2.10) or use a vitreous cutter to aspirate the residual bubble.

Pits & Pearls No. 35 Suprachoroidal haemorrhage (SCH): A SCH can develop suddenly due to strong aspiration especially when the water instead of silicone oil is aspirated. If a SCH develops, you should react quickly. First, perform a fluid/air exchange and in case of valveless trocars, close all ports with plugs to increase the intraocular pressure. This should stabilize the situation. Then inject silicone oil and end the procedure.

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Fig. 5.9 Inflowing water during an air/fluid exchange. Position the fluid needle behind the IOL in order to evacuate the air

4. Internal search Subsequently, we check for peripheral tears or membranes, treat these pathologies and perform a tamponade if necessary. Perform an internal search for breaks and residual membranes, using endoillumination and indentation with a scleral depressor. Try to identify problems that may cause trouble at a later stage, for example, potential new retinal breaks, epiretinal membranes or fibrovascular proliferations. These are best dealt with straightaway rather than during a later, potentially unnecessary additional procedure. The internal search will also identify larger remnant silicone oil bubbles that may hide in the vitreous base. If left behind, these larger residual bubbles can be extremely annoying for the patient. 5. Removal of the trocars Remove the trocars as usual. In most cases, we install a simple air tamponade in order to seal the sclerotomy sites. The 19-gauge sclerotomy should be sutured with a single knot 6-0 Vicryl or a Vicryl 8-0 cross suture.

Pits & Pearls Always check the anterior chamber for residual oil bubbles. In particular, in cases with secondary glaucoma, it is advisable to flush the chamber angle to remove residual bubbles.

5.1

Silicone Oil, Densiron 68® and Oxane Hd® Removal

Pits & Pearls In pseudophakic patients with an intact posterior capsule, perform a posterior capsulotomy with the vitreous cutter via the pars plana at the end of the procedure. These patients will otherwise almost always develop a thick posterior capsular fibrosis, and a YAG capsulotomy is more difficult in eyes in which the retrolental vitreous has been removed.

Pits & Pearls No. 36 ‘Sticky silicone oil’ has sometimes been described after removing conventional or heavy silicone oils. This describes patches of silicone oil that are firmly attached to the retina and cannot be removed with suction alone. In our experience, this is most commonly caused by residual vitreous cortex in the area of adhesion, and the best prevention of sticky silicone oil is a complete removal of this layer during the primary surgery. If you are faced with ‘sticky’ silicone oil, try to fill the eye with heavy liquid. This usually dissolves the sticky patches of oil that can then be removed with conventional suction.

Pits & Pearls No. 37 If a silicone IOL has previously been implanted, small remnant silicone oil bubbles can remained stuck on the posterior IOL surface. They may cause severe visual disturbances if the centre is affected. It may be difficult and sometimes impossible to remove these remnant bubbles. Again, prevention is better in such cases – never use silicone IOL in cases of combined phaco and vitrectomy or cases that have a higher risk for retinal problems. If faced with such residual bubbles, you can try removing them by soaking a small piece of gauze or a cotton bud in heavy liquid and then wiping the posterior IOL surface with this solution. However, if you are unable to remove the remnant bubbles this way, it may be necessary to exchange the IOL. It is, therefore, best to know if a silicone IOL has previously been implanted. If, in addition, you know the optical power of the previously implanted silicone IOL, one can plan for an IOL exchange if needed, thus avoiding additional surgery at a later stage.

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Pits & Pearls Biometry before primary surgery: In cases of combined phaco/IOL and silicone oil removal, it is difficult to obtain a good axial length measurement with silicone oil in situ. If there is a high chance of using silicone oil as a tamponade in a phakic eye, we recommend performing biometry before the primary surgery. Some units routinely perform biometry on all phakic patients undergoing vitrectomy to be prepared if an unforeseen phaco/IOL has to be performed during the initial vitrectomy or for cases where silicone oil is used as a tamponade. If no biometry is available, best results are obtained with the IOL-Master (Zeiss, Germany). Alternatively, if the preoperative refraction is known and both eyes had a fairly similar preoperative refraction, we use the corneal measurements of the eye filled with silicone oil and the axial length of the other eye to calculate the IOL power.

5.2

Vitreous Haemorrhage

DVD

Video 6 Vitreous bleeding of unknown aetiology

A vitreous haemorrhage with attached retina and no associated major vitreoretinal pathology is suitable for the beginner. He/she learns to work with the vitreous cutter and apply a PRP, but does not need to perform any significant manipulations of the retina. This surgery can be performed under local anaesthesia. In the learning phase, the beginner will often perform a PPV with vitreous haemorrhage. The main problem with this procedure is that you have no view into the retina. The procedure is even more difficult when the natural lens is still present due to the risk of injuring the posterior capsule. In the learning phase, perform only PPVs in pseudophakic eyes.

Pits & Pearls B-scan: In cases with vitreous haemorrhage, always perform a detailed preoperative ultrasound examination yourself. Try to determine the state of the posterior vitreous face (attached, partially attached or detached) and the retina. Search for areas of focal vitreoretinal adhesion and traction (retinal breaks, proliferative retinopathy) and, finally, try to identify possible tumours or choroidal detachments. This is also important for the planning of the position of your trocars. Try to view the retina with indirect ophthalmoscopy in all cases of vitreous haemorrhage. You will sometimes find a gap and be able to see the retina. This may provide valuable information regarding the underlying disease and its treatment.

5.2

Vitreous Haemorrhage

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Pits & Pearls Do not underestimate the difficulty of the procedure, even in ‘straightforward’ cases. For example, proliferative retinopathy secondary to retinal vein occlusions or Terson syndrome may be associated with very strong vitreoretinal adhesions that can be difficult to dissect. Simple pulling and lifting with the vitreous cutter may lead to extensive retinal damage.

Pits & Pearls Examine the retrolental vitreous carefully at the slit lamp. In cases of dense vitreous haemorrhage, this may also be cloudy and will need to be removed to enable a good intraoperative view. In phakic patients, this can sometimes be difficult without touching the lens. Prepare everything in advance so a combined phaco/IOL can be performed if needed.

Instruments 1. 3-port trocar 2. 120D lens 3. Vitreous cutter 4. Fluid needle 5. Scleral depressor Tamponade Air, SF6 Individual steps 1. 3-port system 2. Core vitrectomy 3. Posterior vitreous detachment and peripheral vitrectomy 4. Tamponade 5. Removal of the trocar cannulas 1. 3-port system 2. 3-port vitrectomy system and core vitrectomy Vitreous haemorrhage may be caused by several diseases such as diabetes, vein occlusion or haemorrhagic AMD. In many cases, a PVD is present, and the haemorrhage

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Fig. 5.10 PPV for vitreous haemorrhage and posterior vitreous detachment. If you cut a hole in the posterior hyaloid, you will gain a view onto the retina

fills out the vitreous gel behind the lens. However, a partial PVD with focal vitreoretinal adhesions, in particular in the area of retinal proliferations, is also fairly commonly seen. This vitreous haemorrhage reduces the illumination of the light fiber because the light cone is hidden by blood. Therefore, you should first make a core vitrectomy. Keep the first vitreous cutter behind the lens and remove all vitreous gel. It might be easier to work first without BIOM and use the microscope only as you would in cataract surgery. If the view is not improved, then try only to aspirate the liquefied blood. Then try to cut a break in the posterior hyaloid in order to view the retina (Fig. 5.10). It is important to identify the retinal vessels to make sure that you are in the right plane (and not in the subretinal space). If you succeed, continue the vitrectomy from the break in the posterior hyaloid. You then proceed to trim the vitreous base. Do not trim the vitreous base completely because the risk of causing damage to the retina is higher than the benefits. You should, however, try to find the cause of the haemorrhage and treat it (laser, endodiathermy or cryo). If you do not find a central bleeding source, then search in the periphery.

Pits & Pearls The haemorrhagic vitreous blocks/clogs sometimes the infusion. Check the infusion trocar before vitrectomy, and if in doubt, cut the haemorrhagic vitreous around the infusion trocar.

5.2

Vitreous Haemorrhage

83

Pits & Pearls No. 38 Removal of anterior hyaloid: In case of a haemorrhage directly behind the lens, it is may be necessary to remove the anterior hyaloid (see Fig. 4.8). This is an easy procedure in pseudophakic patients but a lens threatening procedure in phakic patients. We perform two techniques: Work at the edge of the lens (i.e. behind the zonules) in order to avoid a lens touch. (1) With help of a serrated jaws forceps, grab the anterior hyaloid/vitreous and pull it towards the centre of the globe. Work from both sides. (2) With help of a vitreous cutter, suck the anterior hyaloid/vitreous (only aspiration) and pull the vitreous cutter towards the centre of the globe. Cut the vitreous there. Work from both sides.

3. Posterior vitreous detachment and peripheral vitrectomy If the posterior vitreous face is not detached, then a PVD should be performed now. If the aetiology of the haemorrhage is, for example a bleeding vessel, treat it now with laser, diathermy or cryo. Beware of focal vitreoretinal adhesions, in particular in the area of retinal proliferations in proliferative diabetic retinopathy or retinal vein occlusions. By simply pulling on them to complete the PVD, you may cause significant retinal damage and breaks. It takes some experience to judge if an epiretinal proliferation can be just ‘peeled off’ or if it needs to be dissected with cutter and/or scissors. In the case of doubt, stop pulling and start cutting.

Pits & Pearls No. 39 How to remove epiretinal blood. (1) Aspirate the blood with a fluid needle. (2) By pressing several times on the side opening/tubing of the fluid needle, water is ejected from the fluid tip and blows up the epiretinal blood. The blood can then be easily aspirated. (3) Clotted blood can be grasped with the Eckardt forceps and be removed with the vitreous cutter.

4. Tamponade An air or gas tamponade is recommended to avoid a re-bleeding into the vitreous cavity. In cases of proliferative retinal disease, it is advisable to perform retinal photocoagulation intraoperatively. It is the best opportunity to do so, as in many cases, a minor postoperative re-bleeding will prevent a good view and a sufficient laser treatment. Some surgeons also use a bevacizumab injection at the end of the procedure to lower the rate of re-bleeding. However, there is no consensus on the advantages or disadvantages of this adjunct.

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5. Removal of trocar cannulas, suture sclerotomies if silicone oil tamponade The trocars are removed, as described above.

5.3

Epiretinal Membranes and Macular Holes

This procedure is suitable for beginners with 50–100 vitrectomies. Both procedures are discussed here, as they involve similar techniques but different dyes. In macular hole surgery, one removes the ILM, which is stained with Brilliant Blue G. In macular pucker or idiopathic ERM, the ERM, which is usually stained with trypan blue, is peeled. Some surgeons recommend a subsequent peeling of the ILM, but there currently is no consensus on this. In a high proportion of cases, the ILM will already be removed together with the ERM. If you wish to peel the ILM after removal of an ERM, you can attempt to stain the ILM with trypan blue. If you do not see the ILM well enough, do not hesitate to stain the ILM with Brilliant Blue G. You will never regret a proper staining of tissue.

Pits & Pearls Combined stains for macular peeling (Brilliant blue and Trypan blue in one preparation) are now commercially available (DORC).

DVD

Video 7a, b Epiretinal membrane and peeling following a fungal infection

Instruments 1. 3-port trocar 2. 120D lens, for peeling: 60D lens or plano concave contact lens 3. Vitreous cutter 4. Fluid needle 5. Eckardt forceps 6. Tano diamond-dusted membrane scraper or CRVO knife 7. Scleral depressor Dye ERM: triamcinolone acetonide, trypan blue Macular hole/ILM: Brilliant Blue G For injection, use a 3-ml syringe with 23-gauge backflush needle (Fig. 5.11 and see material) Tamponade 20% SF6-air, silicone oil (with macular holes in which no postoperative head positioning is possible)

5.3

Epiretinal Membranes and Macular Holes

85

Fig. 5.11 A 3-ml syringe filled with trypan blue and a 23-gauge backflush needle (DORC 1281. A5D06). This syringe size is easy to handle

Individual steps 1. 3-port system 2. Core vitrectomy 3. Induction of PVD 4a. Staining of the ERM 4b. Staining of the ILM 5. Peeling of epiretinal membrane or ILM 6. Tamponade Macular holes: Gas tamponade, Epiretinal membrane: None (BSS) 7. Removal of the trocars 1. 3-port system 2. Core vitrectomy 3. PVD Insert the trocars. If the patient is older than 60 years, consider a combined phaco/ IOL before the vitrectomy. Perform a core vitrectomy and induce a PVD. Position the vitreous cutter in front of the optic disc, the aspiration port almost touching the optic disc – induce maximal suction. Meanwhile, cortex and posterior hyaloid will be engaged in the aspiration port and pull the vitreous cutter slowly towards the lens. The posterior hyaloid membrane can be seen as a fine silky parachute structure (See Sect. 4.2 on induction of a PVD). If you are not sure whether you induced a posterior vitreous detachment successfully, stain the vitreous with triamcinolone or trypan blue. If the posterior vitreous detachment has not been successful, you will now recognize the stained vitreous cortex adjacent to the posterior pole. 4a. Staining of the ERM (epiretinal membrane) The next step is the staining of the ERM with triamcinolone or trypan blue. Stop the infusion. Then take the syringe with the dye in one hand and eject a few drops of the dye outside the eye in order to avoid blockage of the cannula and injection of air. Then insert the syringe until the tip is placed above the macula and slowly inject 3–5 drops of the dye to fall on the macula, as trypan blue is heavier than water (Fig. 5.12).

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Fig. 5.12 Injection of trypan blue in a BSS-filled eye. The infusion is closed. After 15 s, the dye can be aspirated

(Note: The handling of the syringe can be difficult.) After a period of about 15–30 s, turn on the infusion and aspirate the dye with a fluid needle.

Pits & Pearls No. 40 Trypan blue 1. Trypan blue can easily block the injection cannula. This may result in too much force being applied during injection, and a sudden jet of dye can be injected into the eye and that may potentially cause retinal damage. We recommend three steps to avoid such problems: (a) Try to inject yourself. This takes some practice at the beginning but increases your control. (b) Always inject a small amount of dye outside the eye immediately before injecting inside the eye. Once inside the eye, point the cannula towards your light pipe and away from the posterior pole before pointing it at the target area. Any initial jet of dye will hit the light pipe and not the retina. 2. Trypan blue is a very strong dye that temporarily obscures your view of the retina. When injecting too much, one cannot see the vitreous cutter or fluid needle that is needed for its removal. Do not apply suction if you cannot see the tip of your instrument. In such cases, let BSS run through the system and the eye until you can see the tips of your instruments, then start removing the dye from behind the lens and work your way towards the posterior pole.

5.3

Epiretinal Membranes and Macular Holes

87

Fig. 5.13 Perform first a water/air exchange and leave a puddle of water. Then drop about 5 drops of Brilliant Blue G into the puddle. In the picture, you see the bluecoloured puddle on the posterior pole

Pits & Pearls For optimal staining of membranes including ILM with trypan blue, perform a fluid–air exchange, apply several drops of the dye and then wait for 3 min before air–fluid exchange. This is cumbersome but significantly improves your staining in tricky cases.

Pits & Pearls PVD: If you plan to stain with trypan blue, then use it also for PVD. It makes surgery so much easier. But if you stain the vitreous, you need to restain for the membrane.

4b. Staining of the ILM The internal limiting membrane (ILM) stains with Brilliant Blue G particularly well. Because Brilliant Blue G mixes with the water in the vitreous cavity, we use a different staining method: Carry out a water–air exchange and leave a small puddle of water on the central pole. Use a 2-ml syringe with a backflush needle for injection. Inject 2–3 drops of Brilliant Blue G into the puddle, wait 15 s (Fig. 5.13), position the fluid tip in the puddle and remove the dye (Fig. 5.14). Then perform an air/ water exchange. The advantage here is: the dye acts only in the water puddle, and the surgeon can remove it more quickly than if the dye is distributed throughout the vitreous cavity.

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Fig. 5.14 Now, the blue puddle is aspirated with a fluid needle and then an air/ water exchange performed. The advantage of this method is that (1) only the macula is particularly stained and that (2) the dye can be removed in a short amount of time

Fig. 5.15 Preparation for macular surgery. A plano concave contact lens has been placed on the cornea DORC: 1284.DD

5. Peeling of ERM and ILM Before you start with the peeling, you need to change to a higher resolution lens. You may take a macular lens (60D) or a plano concave contact lens, which is placed with contact gel on the cornea (Fig. 5.15). Caution: If you work with a contact lens, you only have a small part of the fundus in your field of view. And the risk of ramming an instrument into the retina is pretty high. Insert, therefore, an instrument only under minimal zoom.

5.3

Epiretinal Membranes and Macular Holes

89

Fig. 5.16 A slight incision of the ILM is performed with a CRVO knife. Alternatively, you can also use a Tano diamond-dusted membrane scraper

Fig. 5.17 An ILM rhexis. The ILM was stained with Brilliant Blue G. The circular removal of the ILM is comparable with the capsulorhexis. But it should be remembered that, in contrast to the convex capsulorhexis, the ILM rhexis runs concave. If you do not consider this, you can quickly drive the forceps into the retina

Peeling of ILM To mobilize the ILM, brush the retinal surface with the Tano diamond-dusted membrane scraper or scrape it with the CRVO knife (temporal, superior or inferior to the macula), until a small defect is created (Fig. 5.16). You can also pinch the ILM with the Eckardt forceps but the risk of retinal bleeding is higher with this technique. Grasp the edge with Eckardt forceps and pull the ILM parallel to the retina (Fig. 5.17). Perform a circular rhexis in the ILM (Fig. 5.18). Always perform the ILM peeling in a circular fashion pulling around and towards the macular

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Fig. 5.18 The size of the ILM rhexis should reach approximately to the upper and lower temporal arcade. In this case, the inferior part of the rhexis should reach closer to the inferior arcade

Fig. 5.19 A membrane, which has been stained with trypan blue, is mobilized with a CRVO knife

hole (just like a capsulorhexis in phaco). Do not just pull the ILM in one sheet across the macular hole. The pathology is that there are usually strong adhesions between the posterior vitreous face and the edge of the macular hole. Therefore, by simply pulling a sheet across, you may enlarge the macular hole. If you do not recognize the edges, stain again. Remove the complete ILM up to the vascular arcade (Fig. 5.19).

5.3

Epiretinal Membranes and Macular Holes

91

Fig. 5.20 The same membrane is now removed completely with the Eckardt forceps

Pits & Pearls PVD and hole closure: If you are unable to perform a safe ILM peeling in macular hole because of a bad view, etc., make sure that you induced a PVD and finish the case without ILM peeling. This achieves a hole closure in about 60–80% of cases. Multiple unsuccessful attempts to peel the ILM may cause more harm than be of benefit.

Peeling of epiretinal membrane Try to mobilize the membrane with a membrane pic or scrape the membrane with the neurotomy knife (temporal, superior or inferior to the macula) until a small defect is created. Once an edge is mobilized, it can be grasped with Eckardt forceps (Fig. 5.19). Pull parallel to the retina until the complete membrane is removed (Fig. 5.20). If the membrane is strongly attached to the retina, do not insist – you might create a retinal defect. If the edges of the membrane tear off and you no longer recognize them, stain again instead and avoid poking around in the retina with the forceps. You (as a beginner) should work very carefully within the papillomacular bundle. You might create irreversible visual field defects. Therefore, you should never start the ILM rhexis in the papillomacular bundle, but in an area with a good staining superior, inferior or temporal to the macula. Small retinal bleedings may occur during peeling. They will cause no harm and vanish within 1 month.

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When the removal of the epiretinal membrane has succeeded change to the 120D lens and, with the help of scleral indentation, examine the retinal periphery for breaks.

Pits & Pearls Membrane and dye: Staining the membrane repeatedly is recommended, as there are often several membranes present. The better the membrane is made visible, the easier it can be peeled.

Pits & Pearls No. 41 ILM peeling and dot haemorrhages: If you are unsure if you are peeling an ERM or an ILM, small dot haemorrhages only occur during ILM peeling and do not appear with ERM peeling.

Pits & Pearls No. 42 In cases of ERM, you can try a ‘two in one’ peeling of ERM and ILM by starting your peeling more peripheral than usual (for example, at the major vessel arcades). If you manage to grasp the ILM, continue your peeling towards the centre. The ERM should sit on top of the ILM, and both layers can be removed with one peeling.

6. Tamponade for macular hole To carry out the gas tamponade, position the fluid tip above the optic disc, then switch to fluid–air exchange. The air streaming in has a different refractive index than water; therefore, the image becomes blurred but more wide-angled. You can focus the image by turning the focus wheel of the BIOM so that the front lens moves up. The image will come into focus again. Since a complete aspiration of BSS is not necessary, avoid an optic disc touch (optic neuropathy). Inject 20% SF6 into the vitreous cavity and decompress the eye by holding the fluid needle in a cannula. Open and close the side opening of the fluid needle with your index finger depending on the tension of the globe (Fig. 5.21). The intraocular pressure is checked with the index finger of the other hand.

5.4

25-Gauge Macular Peeling

93

Fig. 5.21 During injection of gas through the infusion line, you need to decompress the globe by holding the fluid needle in a trocar cannula to relieve pressure

Pits & Pearls Most vitreoretinal surgeons use 20% SF6 as tamponade for macular hole. However, some surgeons prefer 15% C2F6, 14% C3F8 or even 1,000-cSt silicone oil. Silicone oil or heavy silicone oils are also a good choice for patients who are unable to position themselves in the prone position.

7. Removal of the trocars The sclerotomies need not be sutured. Exception: open connection from sclerotomy and conjunctiva with potential vitreous wicking with a risk for endophthalmitis. The big advantage of not suturing is that a postoperative hypertension due to the expanding gas, though rare, allows the gas to escape through the unsutured sclerotomies.

5.4

25-Gauge Macular Peeling

DVD

Video 7c 25-gauge macular peeling

Macular peeling in 25-gauge has the advantage of less trauma to the conjunctiva and an improved sclerotomy closure related to to this type of surgery (Fig. 5.22). In 23-gauge, you sometimes need a suture for the sclerotomy; in 25-gauge, you almost never need a suture. Most companies offer 23-gauge and 25-gauge custom packs including trocars, vitreous cutter and light pipe. In addition, you have to purchase two products: (1) A 25-gauge infusion needle (DORC) for the fluid needle and the syringe with the dye. (2) 25-gauge Eckardt forceps (DORC and Geuder). The neurotomy knife is only available in 25-gauge.

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Fig. 5.22 Postoperative picture after combined 25-gauge phaco/vitrectomy secondary to an ERM. The characteristics are excellent sclerotomy closure, little tissue trauma and subsequent fast postoperative and visual recovery

Fig. 5.23 A 25-gauge cannula (a) with soft tip. We use to remove the soft tip. (b) because it is difficult to insert through a valve. The cannula is used for the fluid needle and for the injection of dye DORC: 1272.SD25

a

b

Instruments 1. 25-gauge 3-port trocar 2. 120D lens, for peeling: 60D lens or plano concave contact lens 3. 25-gauge vitreous cutter 4. 25-gauge fluid needle and dye needle (DORC: 1272.SD25) 5. 25-gauge Eckardt forceps (Geuder: G-36312, DORC: 1286.W05) 6. 25-gauge neurotomy knife 7. Scleral depressor Vitrectomy machine: The removal of the vitreous with 25-gauge is time consuming. You can speed up the procedure significantly by working with high-speed vitrectomy machines (5,000 cuts/min) compared to earlier generation vitrectomy machines (2,500 cuts/min).

Reference

95

Fig. 5.24 Injection of gas: Remove one or two instrument trocars. Inject the gas through the infusion line. The remaining air escapes through the open trocar and/or the sclerotomies. At last remove the infusion line with infusion trocar

Fluid needle: The fluid needle cannula comes with a soft tip (Fig. 5.23a, b). We remove the plastic tip of the infusion cannula with a needle holder in order to achieve an easier insertion into the trocars. We further recommend the use of the fluid needle with active aspiration because a passive fluid–air exchange with 25-gauge is really slow. Insertion of trocars: Insert the 25-gauge trocars in a lamellar fashion as in 23-gauge. Gas tamponade: Remove one or both instrument trocars before injecting the gas (Fig. 5.24).

Reference Romano MR, Groenwald C, Das R, Stappler T, Wong D, Heimann H (2009) Removal of Densiron-68 with a 23-gauge transconjunctival vitrectomy system. Eye (Lond) 23(3):715–717

Bimanual Vitrectomy with 4-Port Trocar System

6

Bimanual vitrectomy is an essential part of modern Minimal Incision Vitreoretinal Surgery (MIVS). By inserting a stationary chandelier light in the sclera (4-port vitrectomy, Fig. 6.1), the surgeon has two active hands. To operate with two active hands is a new and exciting method of surgery. For example, in retinal detachment surgery, one can indent the sclera with one hand and vitrectomize the vitreous base with the other hand. In diabetic retinopathy, one can apply laser photocoagulation up to the ora serrata with the help of a scleral depressor. One can remove membranes with two different instruments and also apply counteraction. For optimal use of a chandelier light, three requirements have to be met: 1. Inferonasal insertion enabling a good rotation of the globe 2. A rigid cable allowing aiming the light source in all directions in the vitreous cavity 3. External light source for optimal illumination

Fig. 6.1 An eye with 4-port vitrectomy. In addition to the known 3-port system, a chandelier light fibre was firmly inserted into the sclera (top left) U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_6, © Springer-Verlag Berlin Heidelberg 2012

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Table 6.1 Features of different types of chandelier lights Chandelier light ALCONa DORCb Light source Photon Xenon Illumination Good Good Rigid cable Yes No Manoeuvrability Average Reduced Method of insertion Trocar Trocar Difficulty of insertion Simple Simple

Synergeticsc Photon Very good Yes Good Sclera Average

a

Chandelier Accurus 8065751574 23-gauge chandelier light 3269.EB06 c 25-gauge Awh chandelier 56.20.25 b

Fig. 6.2 A 23-gauge chandelier light from DORC, which is very easy to insert because it is placed in a trocar. Similar chandelier lights are available from Alcon and Synergetics

The chandelier light is best positioned inferonasally because here, its location does not affect the rotation of the eye. The 12 o’clock or 6 o’clock insertion sites disturb the rotation of the globe, and the light fibre is easily dislocated when the globe is rotated upwards or downwards. The rigid cable allows bending of the light fibre and henceforth the ability to manoeuvre the light to different directions in the vitreous cavity. Only external light sources (Photon or Xenon) have enough power for a sufficient illumination of the vitreous cavity.

6.1

Insertion of Chandelier Light

DVD

Video 8 Insertion of a chandelier light

If you have never used a chandelier light before, then start with one which can easily be inserted. The 25-gauge chandelier light from ALCON and the 23-gauge chandelier light from DORC are relatively unproblematic to use (see Table 6.1) as the light fibre can be placed inside a normal one-step trocar (Figs. 6.2 and 6.3).

6.1

Insertion of Chandelier Light

99

Fig. 6.3 Same 23-gauge chandelier light. Place inferonasally, a one-step 23-gauge trocar. Then insert the light fibre into an ALCON or DORC trocar (with or without valve). DORC: 23-gauge chandelier light 3269.EB06

Fig. 6.4 Practical approach for the insertion of the chandelier light. The hand rotates the eyeball with the cotton wool swab in order to have space inferonasally

The chandelier light from Synergetics is trickier to be put in place but, on the other hand, provides an excellent panoramic illumination of the vitreous cavity. Rotate the globe with a swab in a superotemporal direction so that there is space for the insertion of the chandelier light inferonasally. With the sclerotomy needle supplied by the manufacturer, one first performs a transconjunctival sclerotomy 3.5 mm posterior to the limbus with a perpendicular (not lamellar) path. The chandelier light is then inserted into the sclerotomy. This procedure requires some practice (Figs. 6.4–6.7). The Synergetics chandelier light requires an external photon light source. By bending the rigid cable of the chandelier light, you can manipulate the light source. Sometimes you need to tape the cable to the drape.

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Pits & Pearls No. 43 Chandelier light 1. The insertion of the chandelier light is easier using your hands than with the trocar forceps. But you must exert a relatively strong pressure to insert the tip of the chandelier through the sclera. If you do not succeed, you can expand the sclerotomy with a 23-gauge cannula/needle. The insertion is easier, but the chandelier sits a little loosely in the sclerotomy. 2. Conjunctival chemosis or haemorrhage may make it difficult to identify the sclerotomy. In such cases, open the conjunctiva focally with scissors and forceps in order to visualize the sclerotomy.

Fig. 6.5 Mark the injection site with the scleral marker in the right hand

Fig. 6.6 Pierce the supplied sclerotomy needle perpendicular (not lamellar) through the conjunctiva and sclera

6.1

Insertion of Chandelier Light

101

Fig. 6.7 Take the chandelier optic fibre in the right hand and press it through the orifice in the conjunctiva and sclera into the vitreous cavity. Exert a significant insertion pressure. When the eye is already vitrectomized, use a 23-gauge needle instead of the supplied 25-gauge sclerotomy needle as the eyeball can indent too much

The following surgeries in bimanual technique are listed in increasing levels of difficulty. An exception is PDVR, which has been included in the diabetes section for pathological reasons. But PDVR is, in fact, a very demanding surgery similar to PVR.

Diabetic Retinopathy

7.1

7

Easy Proliferative Diabetic Retinopathy

You can practise the application of panretinal laser photocoagulation (PRP) very well with the 4-port technique (Fig. 7.1). In one hand, you hold the scleral depressor and indent the sclera and retina; in the other hand, you hold the laser probe and apply a PRP up to the ora serrata. In the presence of vitreous haemorrhage, a previous history of panretinal photocoagulation usually facilitates the surgery because it is associated with a higher rate of posterior vitreous detachment and promotes retinal adhesion to the RPE and choroid. DVD

Video 9 Diabetic retinopathy

Fig. 7.1 Indentation of the peripheral retina after application of PRP. A PRP up to the ora serrata is especially easy to perform with the 4-port technique

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/978-3-642-23294-7_7, © Springer-Verlag Berlin Heidelberg 2012

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Advanced cases with tractional membranes should be operated on by an experienced surgeon. The peeling of epiretinal membranes may be difficult, and perioperative bleeding may be difficult to control. Instruments 1. 4-Port trocar with chandelier light 2. 120D lens 3. Vitreous cutter 4. Fluid needle 5. Scleral depressor 6. Endodiathermy 7. Laser probe Tamponade Air, SF6 or silicone oil Individual steps 1. 4-Port system 2. Core vitrectomy 3. Posterior vitreous detachment and peripheral vitrectomy 4. Endodiathermy 5. Panretinal photocoagulation 6. Tamponade 7. Removal of the trocar cannulas 1. 4-Port system 2. Core vitrectomy For details, see Sect. 5.2. 3. Posterior vitreous detachment and peripheral vitrectomy If there are tractional membranes present at the central pole, you should not induce a posterior vitreous detachment with the vitreous cutter because this action may cause breaks in the central retina. These membranes must be removed with peeling instruments. See further in next chapter 7.2 on ‘Complicated Proliferative Diabetic Retinopathy (PDVR)’.

Pits & Pearls PDR: Never underestimate a vitreous haemorrhage in proliferative diabetic retinopathy. Even if it may not look like a complicated situation preoperatively, there may be strong vitreoretinal adhesions at the site of even the smallest neovascular proliferations. Do not rush into such cases and try to create a quick PVD with suction over the posterior pole – try to identify and isolate each and every proliferation and treat it with great care.

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR)

105

4. Endodiathermy Cauterize retinal bleeding sites with endodiathermy. Start with relatively low energy, as too vigorous endodiathermy may create breaks in ischemic retinal tissue. Avoid diathermy on the disc; this may cause destruction of nerve fibre bundles. If the bleedings occur within the temporal vascular arcades, then use a laser probe to cauterize the bleedings instead. Often you have to work bimanually. Aspirate the blood with the left hand and cauterize the bleeding source with endodiathermy or the laser probe in the right hand.

Pits & Pearls Postoperative vitreous haemorrhages are the number one problem following vitrectomy for proliferative diabetic retinopathy. In order to lower your rate of this complication, be meticulous with your haemostasis. Watch out for small oozing bleeding sites after you have performed your PRP. Even small collections of blood point at continuous bleeding sites that should be treated before closing up. Try to remove all peripheral vitreous with remaining blood in it – this may wash out postoperatively and be an additional source of postoperative vitreous haemorrhage.

5. Panretinal photocoagulation in diabetes mellitus We recommend completing a PRP intraoperatively in all cases of vitrectomy for proliferative diabetic retinopathy. This is the best opportunity to complete the PRP, as re-bleeding into the vitreous cavity is a common problem following vitrectomy, which will have a negative influence on performing additional PRP after the vitrectomy. Use the scleral depressor and apply a dense PRP up to the ora serrata. For PRP, we recommend the following laser parameters: power: 150 mW, duration: 200 ms, interval: 200–300 ms, at an OcularLight GL Company Iridex. These values are dependent on the device and the pigmentation of the fundus. After endolaser coagulation, check if a new bleeding occurred at the posterior pole and treat it before you move on to the tamponade. 6. Tamponade Use air or gas in eyes with a mild bleeding and silicone oil in eyes with a strong bleeding.

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR)

An eye with advanced diabetic changes that has received insufficient laser photocoagulation and needs surgical removal of tractional membranes should be reserved for advanced surgeons. There are different recommendations regarding the type of anaesthesia. Very complicated cases are usually operated on under general anaesthesia, in particular in young patients with insulin-dependent diabetes. On the other hand,

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some surgeons prefer local anaesthesia for such cases; the reason behind this is that a rise in blood pressure and coughing attacks can sometimes be seen when the patient is waking up from the anaesthesia with intubation. This may increase the risk for postoperative re-bleedings into the vitreous cavity immediately following dissection of epiretinal neovascularizations. In contrast to PVR detachment, peeling in diabetic retinopathy is performed from the periphery to the centre. DVD

Video 10a–c Difficult diabetic retinopathy / PDVR

Instruments 1. 4-Port trocar 2. 120D lens, for peeling: 60D front lens 3. Vitreous cutter 4. Fluid needle 5. Eckardt forceps 6. Straight/horizontal scissors or vertical scissors 7. Membrane pic or knob spatula 8. Endodiathermy 9. Lasertherapy 10. Scleral depressor Dye Triamcinolone or Trypan blue Tamponade 20% SF6, 12–14% C3F8 or silicone oil Individual steps 1. 4-Port system 2. Core vitrectomy 3. Peripheral vitreous rhexis 4. Bimanual dissection of tractional membranes 5. Apply PRP 6. Tamponade 7. Removal of the trocars 1. 4-Port system 2. Core vitrectomy Procedure: 4-port trocar system. The vitreous haemorrhage reduces the brightness of the chandelier light. Therefore, perform first a core vitrectomy. If a lot of liquefied blood is present, aspirate it with the vitreous cutter of the fluid needle. Then cut the peripheral vitreous using the scleral depressor. Try to remove the haemorrhage surrounding the

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR)

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Fig. 7.2 Do not start with a central PVD in such a difficult diabetic retinopathy. You will create retinal breaks when pulling at the fibrovascular membranes. Perform first a peripheral rhexis

chandelier light in order to improve the fundus view. If you have a good view of the posterior pole, focus the image again before continuing with vitrectomy. 3. Peripheral vitreous rhexis In severe diabetic retinopathy, tractional membranes are present on the posterior pole. If you induce a PVD, you may be lucky in some cases and the epiretinal neovascularisations will just peel off the retina together with the vitreous face. However, there is a considerable risk of causing major retinal damage by pulling on the membranes and inducing tears in the ischemic and less resistant retina (Fig. 7.2). Therefore, every case of proliferative diabetic retinopathy should be approached with caution and a PVD should not be induced with the usual method of suction over the posterior pole and pulling on the vitreous face. To avoid this damage, you should perform a peripheral vitreous detachment. In most cases of proliferative diabetic retinopathy, a partial vitreous detachment is present and responsible for the vitreous haemorrhage. This means that the vitreous is still attached at the disc but partially detached in the mid-periphery, where it is pulling on the neovascularisations that extend along the posterior vitreous face. Try to find where the peripheral vitreous is detached. Here you create an opening of the posterior hyaloid and remove the vitreous along the posterior vitreous face (Fig. 7.3) on a constant level in a circular fashion (peripheral vitreous rhexis). Do not vitrectomize the area where the vitreous is attached. Then carefully vitrectomize further from the periphery toward the beginning of the tractional membranes. Be careful that you do not exert any strain on the membranes. If you succeeded with the peripheral vitreous rhexis, you can now remove the tractional membranes bimanually.

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Fig. 7.3 Peripheral rhexis in an advanced PDR with retrohyaloidal bleedings. You can see a rhexis in the posterior hyaloid in the whitish part of the posterior hyaloid

Fig. 7.4 In advanced PDVR, the membranes can be removed more easily with bimanual surgery. Here the posterior hyaloid is lifted up by aspiration with the fluid needle, and a vitreoretinal adhesion is cut with the straight vitreous scissors

4. Bimanual dissection of tractional membranes The fibrovascular membranes are usually located along the vascular arcades. The way to success is bimanual dissection: For grasping the membranes, both the Eckardt forceps and the fluid needle are suitable. The Eckardt forceps grasp the membrane, and the fluid needle aspirates the membrane. For manipulation of the membrane, use the knob spatula, the horizontal or vertical scissors and the vitreous cutter. Grasp the peripheral portion of the membrane with the Eckardt forceps or a fluid needle in one hand and delaminate the membrane with the knob spatula in the other hand (Figs. 7.4, 7.5 and 7.6). The membranes are partially attached by ‘tissue bridges’ to the retina. These bridges have to be identified by careful delamination and then be cut with the horizontal or vertical scissors. If a bleeding occurs during this step, you can either

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR)

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Fig. 7.5 In a tractive diabetic retinopathy, it is wise to stain the membranes with trypan blue. The membranes can be grasped with the Eckardt forceps and delaminated with the knob spatula

hold the knob spatula for about 1 min onto the bleeding source (1 min is longer than you think) or – what we prefer – to bimanually aspirate the source of bleeding with the fluid needle and cauterize it. The tractional membranes are dissected and removed through a constant change of instruments between delamination and cauterization.

Pits & Pearls No. 44 Diabetes and anti-VEGF: A major problem during the surgery of diabetic retinopathy is multiple bleedings from the proliferations. You can already create preoperatively a much more favourable starting point through the intravitreal injection of a VEGF inhibitor 1 week before the PPV. The PPV runs then a lot more pleasantly, since the intraocular haemorrhages are much less and the dissection of fibrovascular tractional membranes is facilitated. Caution: A tractive detachment might become worse after injection of a VEGF inhibitor. The patients at risk for this sever complication are typically insulin-dependant patients with annual fibrosis at the posterior pole and little to no PRP.

Pits & Pearls No. 45 Diabetes and cataract: If you have an opacified lens, then also perform a cataract operation before the vitrectomy. Especially in advanced diabetic retinopathy cases, you avoid anterior segment inflammation with posterior synechiae. A diabetic eye, which is pre-treated with anti-VEGF and cataract surgery, is much easier to vitrectomize. Lens-sparing vitrectomy: We experienced good results with PPV and SF6 in young diabetic patients. Even after 10–20 years, the lens hardly opacifies.

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Pits & Pearls No. 46 Diabetes and intraoperative haemorrhage Slight bleeding: (1) Increase the intraocular pressure to approximately 40 mmHg. (2) Aspirate the blood with the fluid needle and cauterize bimanually the bleeding source with endodiathermy (or laser therapy). Moderate bleeding and bleeding at the optic disc: Compress the source of bleeding 1 min with the knob spatula. Severe bleeding: If the bleeding is so severe that there is no view, and despite aspiration with the fluid needle it does not clear up, then you should perform a fluid–air exchange. The bleeding will stop. Try now to cauterize the bleeding source with endodiathermy or compress it mechanically with the knob spatula.

a

b

Fig. 7.6 (a) These extensive membranes of a 24 year old patient are best removed with bimanual technique. (b) The membrane can be grasped with a fluid needle or a forceps and the adhesions are removed with a blunt instrument and straight scissors

7.2

Complicated Proliferative Diabetic Retinopathy (PDVR)

Fig. 7.7 (a) Preoperative situation of a 41 year old patient with untreated diabetic retinopathy. (b) The same eye after extensive bimanual peeling, application of PRP and injection of silicone oil

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a

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5. Apply PRP If you created iatrogenic tears with lifted edges during removal of the tractional membranes, you must, if the peeling is finished, instill PFCL and laser treat these breaks. In addition, a PRP should be performed. By using the scleral depressor, you can laser treat up to the ora serrata. After endolaser coagulation, check if a new bleeding occurred at the central pole and treat it before you move on to the tamponade. 6. Tamponade In most cases, we use air or 20% SF6 and sometimes 12% C3F8 or 1,000 cSt silicone oil. Use silicone oil in difficult cases (Fig. 7.7). 7. Removing the trocars The trocars are removed as described in ‘Special Techniques of PPV’ section. If silicone oil is used, one should suture the sclerotomies, otherwise oil might translocate under the conjunctiva.

Dislocated Intracoular Lens (IOL) and Dropped Nucleus

8.1

8

Dislocation of the IOL with Capsular Bag due to Zonulolysis

The PPV for a dislocated IOL should be performed by an advanced surgeon because the complication profile is high. DVD

Video 11a, b Luxated IOL and subluxated IOL

Surgical preparation: The surgery should take place under general anaesthesia as it is not a routine surgery and the complication profile is high. After removal of the capsular bag, you can suture the IOL to the sclera. One can suture a 3-piece IOL as well as a 1-piece IOL to the sclera. Alternatively, an iris-claw lens can be implanted. Instruments 1. 4-Port trocar 2. 120D lens 3. 2× Eckardt forceps 4. Polypropylene 10-0 suture with curved needle (i.e. Alcon Polypropylene, blue monofilament, double-armed; 8065307601) Tamponade Intra-operative: PFCL Post-operative: None Individual steps 1. Opening of the conjunctiva at 3 and 9 o’clock + 4-port trocar 2. Core vitrectomy 3. PFCL bubble as macular protection 4. Grasp the IOL and cut the capsular bag 5. Two sclerotomies (1.5 mm posterior to the limbus) at 3 and 9 o’clock 6. Extraction of a haptic at 3 o’clock, place a suture onto the haptic and push it back into the eye. The same procedure at 9 o’clock U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_8, © Springer-Verlag Berlin Heidelberg 2012

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Dislocated Intracoular Lens (IOL) and Dropped Nucleus

Fig. 8.1 A dislocated IOL with capsular bag. After removal of the capsular bag, the IOL can be sclera-fixated

7. Suture the haptic suture in a snake shape to the sclera 8. Removal of PFCL and closure of conjunctiva 1. Opening of the conjunctiva at 3 and 9 o’clock + 4-port trocar Open the conjunctiva at 3 and 9 o’clock to make space for one sclerotomy and a scleral suture, i.e. approximately from 2 to 4 o’clock and from 8 to 10 o’clock. Then cauterise the bleeding vessels. Insert the trocars and the chandelier light as usual for the 4-port trocar system. 2. Core vitrectomy 3. PFCL for macular protection 4. Grasp the IOL and cut the capsular bag First, vitrectomise the central vitreous. Confirm the presence of a PVD or create a PVD before injecting PFCL. Then inject a small PFCL bubble at the posterior pole to protect the macula (Fig. 8.1). Hold the IOL bimanually with the forceps and cut the capsular bag with the vitreous cutter (Figs. 8.2–8.4). 5. Two sclerotomies (1.5 mm posterior to the limbus) at 3 and 9 o’clock 6. Extraction of a haptic at 3 o’clock, place a suture onto the haptic and push it back into the eye. The same procedure at 9 o’clock In case of a 3-piece IOL, fasten the suture in the middle of the haptic, and in case of a 1-piece IOL, at the end of the haptic (Fig. 8.5). In the area of the sulcus, 1.5 mm posterior to the limbus, perform an approximately 1.3-mm sclerotomy (Fig. 8.6). The sclerotomy must be perpendicular (i.e. approximately 90º to the sclera) in order not to harm the anterior chamber. Via the sclerotomy at 3 o’clock, grasp a haptic with an Eckardt forceps (Fig. 8.7) and pull it out of the eye. Cut a 10-0 polypropylene suture with two curved needles in two halves. Then place a

8.1

Dislocation of the IOL with Capsular Bag due to Zonulolysis

Fig. 8.2 Bimanual technique. Grasping the fibrotic capsule with a serrated-jaw forceps and removing it with a vitrector

Fig. 8.3 If the fibrotic capsule is too hard for the vitrector, you may either remove it with the Fragmatome or luxate it into the anterior chamber. Perform a 2.75-mm tunnel and remove the hard capsule. Do not extract the IOL

Fig. 8.4 Now, the 3-piece IOL is positioned with a forceps in the middle of the vitreous cavity area, and the residual capsular bag is removed with the vitreous cutter

115

116 Fig. 8.5 A luxated 1-piece IOL can also be sclerafixated. It is important that the suture is fastened to the end of the haptic

Fig. 8.6 After opening the conjunctiva, two sclerotomies at 3 o’clock and 9 o’clock are placed 1.5 mm behind the limbus. It is important to perform a perpendicular (90º) sclerotomy; otherwise you will damage the anterior chamber

Fig. 8.7 In this step, one haptic of the IOL is grasped and extracted through a sclerotomy at 3 o’clock. The photo shows how the Eckardt forceps grasps a haptic in order to extract it

8

Dislocated Intracoular Lens (IOL) and Dropped Nucleus

8.1

Dislocation of the IOL with Capsular Bag due to Zonulolysis

117

Fig. 8.8 The haptic was drawn outside with Eckardt forceps. In the picture, a 10-0 polypropylene suture is tied to one haptic. Subsequently, the haptic is pushed back into the eye, and the suture is sutured in 5 snake-shaped stitches without a final knot to the sclera

n

tio

ina

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Inf

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o nd

E

Cm

olte

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Fig. 8.9 Drawing of the suture technique. Suture 5 snake-formed stitches in and out the sclera and cut the suture without a knot

10-0 Prolene suture to the haptic (Fig. 8.8) and insert the haptic back into the eye. Perform the same manoeuvre at the 9-o’clock sclerotomy. After the haptic has been pushed back, centre the IOL by pulling carefully on both sutures. 7. Suture the haptic suture in a snake shape to the sclera Different techniques are now possible. One can place five U-shaped sutures in the shape of a snake to the sclera and then cut off the suture without a knot. A knot can cause a disturbing foreign body sensation to the patient (Fig. 8.9). Alternatively, you can prepare a scleral flap, fasten the suture to the sclera and place the knot under the scleral flap. 8. Removal of PFCL and closure of conjunctiva Aspirate the PFCL. The conjunctiva is closed with an Vicryl 8-0 suture. The sclerotomies do not need to be sutured.

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8.2

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Dislocated Intracoular Lens (IOL) and Dropped Nucleus

Dropped Nucleus

A PPV due to a dropped nucleus can be performed by a beginner if the lens material is soft. If the lens is hard, the surgery becomes exponentially more difficult. In this case, the surgery should be performed by an advanced vitreoretinal surgeon due to the high complication profile (injury of the retina and choroid). There is a significant rate of post-operative retinal detachments after these complications of cataract surgery. The surgery should take place under general anaesthesia; however, if an experienced surgeon is called to a cataract surgery going wrong in the neighbouring theatre, it may be best to finish the surgery under local anaesthesia if this is sufficient for the expected length of the procedure. DVD

Video 12a, b Extraction of dropped nucleus with fragmatome or with ICCE

Assess pre-operatively whether or not the anterior capsule is intact. If the anterior capsule is intact, implant a 3-piece IOL in the sulcus. If it is not intact, you can implant a sclera-fixated, or even easier an iris-fixated IOL. You need a combined phaco/PPV set and also: Instruments 1. 4-port trocar (1 × 20-gauge sclerotomy) 2. 120D lens 3. Fragmatome (20-gauge or 23-gauge) Tamponade Intra-operative: PFCL Post-operative: None Individual steps 1. 4-port system (superotemporal: 20-gauge sclerotomy without trocar) 2. Anterior vitrectomy via pars plana 3. Removal of residual cortex from the lens capsule via paracentesis 4. Core vitrectomy 5. PFCL bubble as macular protection 6. Phacoemulsification of the nucleus with fragmatome and fluid needle 7. Implantation of an IOL 8. Removal of PFCL 1. 4-port trocar (1 × 20-gauge sclerotomy) We use a 4-port vitrectomy because we work bimanually in step 6. Superotemporally we open up the conjunctiva in the area of the sclerotomy, perform a 20-gauge sclerotomy and insert no trocar. 2. Anterior vitrectomy via pars plana 3. Removal of residual cortex from the lens capsule via paracentesis

8.2

Dropped Nucleus

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Nucleus

Hard nucleus

Soft nucleus

Nucleus

Flu

id

ne

r

ed

tte

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s ou

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PFCL

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PFCL

Fig. 8.10 Flowchart of operation techniques for dropped nucleus, depending on the hardness of the nucleus

4. Core vitrectomy The anterior vitreous is cut with the vitreous cutter via pars plana. Perform a circle with aspiration port to 12 o’clock and to 6 o’clock. Then the residual cortex is aspirated from the lens capsule with the vitreous cutter via a paracentesis. It is important that you switch the vitreous cutter to aspiration and not to cutting. Otherwise there is a risk of destroying the anterior capsule. If the lens capsule is free from the cortex, continue the vitrectomy via the pars plana. 5. PFCL for macular protection 6. Phacoemulsification of the nucleus with Fragmatome and fluid needle The bigger and the harder the lens, the more difficult the operation will be (Fig. 8.10). Removal of a complete and hard nucleus: Modified ECCE method (SICS) (method 1). Removal of soft lens fragments/nucleus: Use a vitreous cutter (method 2). Removal of hard lens fragments: Use a fragmatome (method 2).

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Dislocated Intracoular Lens (IOL) and Dropped Nucleus

Fig. 8.11 Dropped nucleus. Depending on how hard the nucleus is, you can remove it with the fragmatome or extract it in toto with SICS technique

Fig. 8.12 Injection of PFCL to lift the nucleus and protect the macula

Method 1 (Luxation and extraction of the nucleus in the anterior chamber) Phacoemulsification: Perform a core vitrectomy, induce a PVD, inject PFCL up to the sclerotomies, the nucleus is then pushed up to the level of the pupil. Then, inject viscoelastic into the anterior chamber and luxate the dislocated nucleus into the anterior chamber with a 23-gauge membrane pic from the pars plana and a pushpull from the paracentesis. Now inject viscoelastic above the lens to protect the endothelium. Then emulsify the nucleus with a normal phaco handpiece. The disadvantage of this method is that the phacoemulsification disintegrates the nucleus into small pieces that can slide away on the PFCL bubble in the retinal periphery and must be retrieved from there. The viscoelastic in the pupil can help to hold the lens fragments in the anterior chamber. The second disadvantage is an injury of the endothelium with the phaco energy, which may result in a decompensated cornea if you have a hard lens and a less advanced phaco handpiece. SICS technique: If the nucleus is too hard for the phaco (Fig. 8.11), you can extract the nucleus faster and with a lower risk of complications in toto (Figs. 8.12–8.15).

8.2

Dropped Nucleus

Fig. 8.13 The dropped nucleus has been lifted with PFCL behind the pupil

Fig. 8.14 Injection of viscoelastic into the anterior chamber and luxation of the nucleus into the anterior chamber with two membrane pics from pars plana

Fig. 8.15 Perform an 8-mm broad frown incision and extract the nucleus with the fishhook technique

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Dislocated Intracoular Lens (IOL) and Dropped Nucleus

Fig. 8.16 This dropped nucleus is removed with the fragmatome. First PFCL is injected in order to protect the macula

Fig. 8.17 The dropped nucleus is lifted bimanually with the fluid needle into the centre of the vitreous cavity and removed with the Fragmatome. The Fragmatome is difficult to handle because the lens fragments tend to jump away from the Fragmatome tip. This procedure is safer performed bimanually because monomanually, the lens fragments have to be aspirated with the Fragmatome from the retina, which may cause iatrogenic breaks

I recommend the so-called SICS technique (small-incision cataract surgery), which is a modified form of ECCE. In short: 6–8-mm-wide frown incision, 5–6-mm capsulorhexis, mobilisation of the nucleus, injection of viscoelastics below and above the nucleus and finally extraction of the nucleus with loop, fishhook or viscoelastics. The incision need not be sutured. Method 2 (Extraction of the nucleus in the vitreous cavity) Instill a small PFCL bubble so that the macula is protected from the nucleus. Verify or induce and complete a PVD before you inject PFCL. Soft lens material can be removed first with the vitreous cutter (approximately 400 cuts/min). For hard lens fragments, you can use the fluid needle in your left hand and the fragmatome in the right hand. Aspirate the lens fragments with the fluid needle and emulsify them in the central vitreous cavity with the fragmatome. This procedure is performed repeatedly until all the lens fragments are removed (Figs. 8.16–8.18).

8.2

Dropped Nucleus

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Fig. 8.18 The fluid needle lifts a dislocated lens fragment from the retina to the centre of the vitreous cavity where it can be cut with the vitreous cutter without danger to the retina

If you perform this procedure without fluid needle (only with the fragmatome), there is a risk that during the frequent aspiration of the lens fragments with the fragmatome, you may injure the retina (retinal break) or the choroid (choroidal haemorrhage). In addition, the frequent aspiration of the lens fragments clogs the vitreous cutter. If the suction is not working properly, it is even easier to induce damage to the retina or choroid. At the end, the PFCL has to be removed.

Pits & Pearls No. 47 Dropped nucleus and PFCL: In cases of vitrectomy for dropped nucleus, beware of injecting PFCL into eyes with blood in the vitreous cavity or on the retina (either from the sclerotomies or from retinal injuries). The mixture of lens fragments, blood and PFCL can form a type of ‘superglue’ that can stick lens fragments to the retina, which are virtually impossible to remove without significant retinal injury. Make sure that all blood is cleared before injecting PFCL in such cases.

7. Implantation of an IOL If more than two-third of the anterior capsule is intact, the lens is implanted into the sulcus (‘haptic out, optic in’) (Fig. 8.19). If not, fixate a lens to the sclera or to the iris (e.g. PMMA Verisyse) (Fig. 8.20). 8. Removal of PFCL Aspirate the PFCL and perform an internal serach for retinal breaks

124 Fig. 8.19 The IOL is implanted in the sulcus in an eye with posterior capsular defect. The haptics are placed in the sulcus, and the optic is pressed with the push-pull instrument behind the anterior capsule

Fig. 8.20 Constriction of the pupil with Miochol. Implantation of an iris-fixated Verisyse PMMA behind the pupil

8

Dislocated Intracoular Lens (IOL) and Dropped Nucleus

Endophthalmitis

9

DVD

Video 13 Endophthalmitis

The Endophthalmitis Vitrectomy Study recommends intravitreal antibiotics if the visual acuity is greater than hand motion and PPV if visual acuity is equal to light perception [1]. In practice, most colleagues tend to perform a vitrectomy at earlier stages with a better visual acuity. In every tertiary vitreoretinal centre, clear treatment guidelines should be established; all necessary antibiotics and an examination of the microbiological specimens should be available at all times. In recent years, there is a significant increase of endophthalmitis in patients following intravitreal injections of anti-VEGF agents. In contrast to the previously more common endophthalmitis following cataract surgery, the majority of these patients are still phakic, and the lens or opacified vitreous adjacent to the lens might impair the view of the posterior segment for vitrectomy. If you perform a phaco, then open the posterior capsule and do not insert an IOL in order to improve the outflow of aqueous and reduce bacterial growth in the capsular bag. If you are contacted from a peripheral institution regarding a patient with presumed endophthalmitis and a delay of several hours before the patient can be seen in your institution is to be expected, it is advisable to ask the referring ophthalmologist to perform an intravitreal injection of antibiotics before sending the patient. Time is of paramount importance in treating endophthalmitis, and the benefit of earlier antibiotic injection overrides the disadvantages of a short delay in the referral and possibly the failure to obtain a specimen for microbiology. Preparation of antibiotic therapy (according to the guidelines of the EVRS) 1 mg/0.1 cc Vancomycin and 2.25 mg/0.1 cc Ceftazidime (Fortum)

U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_9, © Springer-Verlag Berlin Heidelberg 2012

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You need: 1× Vancomycin 500 mg and 2× plastic ampoules 10 ml NaCl 9 mg/ml (9%) Vancomycin 1. Dissolve 500 mg of Vancomycin in 10 cc NaCl 9 mg/ml (first ampoule). 2. Aspirate 2 cc of the second NaCl 9 mg/ml ampoule and discard it. 3. Add 2 cc of the dissolved Vancomycin (first ampoule) into 8 cc of NaCl 9 mg/ml (second ampoule). The ampoule contains now 10 cc of Vancomycin 10 mg/ml. 4. Inject 0.1 cc (=1 mg) Vancomycin into the vitreous cavity. (Remark: cc = ml) You need: 1× Fortum 500 mg and 2× plastic ampoules 10 ml NaCl 9 mg/ml (9%) Ceftazidime 1. Dissolve 500 mg of Fortum in 10 cc NaCl 9 mg/ml (first ampoule). 2. Aspirate 8.8 cc of the second NaCl 9 mg/ml ampoule and discard it. The second ampoule contains now 1.2 cc NaCl 9 mg/ml. 3. Draw 1 cc of the dissolved Fortum and inject it into the second ampoule. The second ampoule contains now 2.2 cc Fortum 22.7 mg/ml. 4. Inject 0.1 cc (=2.27 mg) Fortum into the vitreous cavity. Instruments 1. 3-port or 4-port trocar 2. Insulin syringe for sampling Potential tamponade Silicone oil Individual steps 1. 3-port or 4-port system 2. Specimen from the anterior chamber 3a. Pseudophakic eye: Flushing of the anterior chamber and the capsular bag 3b. Phakic eye: Phaco 4. Specimen from the vitreous cavity 5. Vitrectomy 6. If possible, induction of posterior vitreous detachment 7. Intravitreal antibiotics 8. Tamponade with silicone oil 1. 3-port system You can use a 3-port or a 4-port trocar system. 2. Specimen from the anterior chamber

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Endophthalmitis

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Fig. 9.1 Fibrin and pus in an anterior chamber of an eye with endophthalmitis. Perform an anterior chamber tap

3a. Pseudophakic eye: Flushing of the anterior chamber and the capsular bag After performing a paracentesis, perform an anterior chamber tap (Fig. 9.1). Then rinse the anterior chamber and the capsular bag thoroughly with BSS and irrigation/ aspiration (I/A). With foudroyant endophthalmitis, it is appropriate to explant the IOL with the capsular bag. 3b. Phakic eye: Phaco Perform a phaco and cut a round hole in the posterior capsule with the vitreous cutter from pars plana.

Pits & Pearls No. 48 Fibrin in the anterior chamber can be extracted easily with Eckardt forceps via a paracentesis.

4. Specimen from the vitreous cavity Take a sample from the central vitreous with an insulin syringe. You can either connect the syringe to the vitreous cutter or aspirate manually (dry vitrectomy) or you can send the vitrectomy cassette to microbiology.

Pits & Pearls Microbiology: The time period between obtaining the specimen and processing in the microbiology laboratory is extremely important. The longer this time period, the less likely it is to identify the causative pathogen. Therefore, good communication between the ophthalmologist and the microbiologist is

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essential. As patients with endophthalmitis are often treated out of normal working hours, a clear protocol for obtaining and processing the specimen (whom to contact, how to send the specimen, where to send the specimen, etc.) is essential.

5. Vitrectomy Follow the usual steps of vitrectomy. Be very careful not to induce iatrogenic retinal breaks, as these will necessitate a silicone oil tamponade in endophthalmitis cases. In cases of severe endophthalmitis, it is sometimes impossible to identify all structures correctly. It is therefore very easy to cut through the retina. In such cases, work your way very carefully from “top to bottom”, e.g. from the space behind the lens to the posterior pole. Try to identify retinal vessels in order to identify the correct working plane. If you are unsure and you only see a yellowish mass behind the lens, start cutting in the periphery – the retina might be detached and pulled anteriorly; it is then better to cut through the peripheral retina. Focus on identifying retinal vessels as your guideline as early as possible.

Pits & Pearls Do not open the pars plana infusion without visualizing it first (see Chap. 4). If you are unable to see the internal opening of the infusions port, start the vitrectomy using an infusion via an anterior chamber maintainer.

6. If possible, induction of posterior vitreous detachment Next, a vitrectomy is performed (Fig. 9.2). The retina often shows panretinal haemorrhages and epiretinal pus (Fig. 9.3). You should try to perform a posterior vitreous detachment so that as much vitreous as possible is removed. The bacteria then have poorer growing conditions. Caution: The retina in endophthalmitis is very fragile. It is easy to induce breaks. 7. Intravitreal antibiotics Now Vancomycin and Ceftazidime are injected into the eye. 8. Potential tamponade: Silicone oil Some surgeons suggest silicone oil as tamponade because it is attributed with bacteriostatic properties. Others use no tamponade. In the latter, one has no or only a reduced view of the fundus during the first postoperative days, after about 3 days, the eye will clear up. If you have identified or created a retinal break, we recommend silicone oil tamponade. The antibiotics can be injected into the anterior chamber or into the silicone oil. There is no place for a gas tamponade in endophthalmitis cases.

Reference

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Fig. 9.2 Infiltrated vitreous of an eye with endophthalmitis 5 days after injection of Ranibizumab. There is almost no view to the retina

Fig. 9.3 The same eye after PVD, PPV and silicone oil injection. You see peripheral dot and blot haemorrhages, epiretinal pus on the posterior pole and a macular scar

Reference Endophthalmitis Vitrectomy Study Group (1995) Results of the Endophthalmitis Vitrectomy Study. A randomized trial of immediate vitrectomy and of intravenous antibiotics for the treatment of postoperative bacterial endophthalmitis. Arch Ophthalmol 113(12):1479–1496

Retinal Detachment

10.1

10

Detachment Surgery

A rhegmatogenous retinal detachment (RRD) with multiple breaks is a surgery for experienced surgeons, as there is a significant complication profile. The beginner should start with a localized detachment (one to two quadrant detachment and a single break), as this is usually easier to manage.

Pits & Pearls Lincoff rules: The key for the understanding of a rhegmatogenous detachment are the four Lincoff rules. They indicate where the primary break is located with a very high probability (Kreissig 2000).

DVD

Video 14 Retinal detachment

How do you deal with what type of detachment? The general recommendations are that in phakic patients, one should perform a buckling surgery if possible. In pseudophakic patients, a PPV is recommended (Heimann et al. 2007). In pseudophakia with multiple breaks, we always perform a PPV; this is often named ‘primary vitrectomy for retinal detachment’. There is a tendency towards combining all PPV for RRD in all phakic patients of 50 years or above with phako & IOL. This greatly facilitates the trimming of the vitreous base that is necessary in primary vitrectomy. The three major steps of RRD surgery are: 1. Removal of the lens 2. The use of a chandelier light 3. Shaving of the vitreous base under PFCL U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, DOI 10.1007/ 978-3-642-23294-7_10, © Springer-Verlag Berlin Heidelberg 2012

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Diagram 10.1 Flow chart for retinal detachment

Retinal Detachment

Retinal detachment

Phakic >50 yrs Phaco

Pseudophakic