EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78721
January 2012 rePlay online content Tools and techniques Pars plana vitrectomy for the anterior segment surgeon by Lisa B. Arbisser, M.D. D ealing with capsule ruptures and vitreous presentation is one as- pect of anterior segment surgery that the average cataract sur- geon dreads. I believe this is in part due to a lack of adequate training and experience with this infrequent complication of cataract surgery. In this month's column, Lisa Arbisser, M.D., presents an incredi- bly valuable systematic approach for suc- cessfully conquering vitreous. This article gives useful tips and pearls in addition to a better understanding of proper machine settings for 20-gauge and smaller vitrec- tors. This is an extremely useful article that I believe should be read repeatedly, especially before your next difficult and challenging case. I am confident you will find this educational and practical. Richard Hoffman, M.D., Tools & techniques editor Dr. Arbisser, adjunct clinical associate professor, John A. Moran Eye Center, University of Utah, Salt Lake City, discusses the settings and strategies involved for optimal outcomes I Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) Or view the video at www.eyeworld.org/replay.php. n complicated cataract cases involving vitreous, our primary goal is to avoid intra-op and post-op retinal traction. Seque- lae of tears and detachment are the primary reasons for poor out- comes. Our secondary goal is to leave a clean anterior segment and a stable intraocular lens while avoid- ing collateral capsule, iris, and corneal damage. Early capsule breach recognition helps limit complications progress- ing from ruptured posterior capsule with intact hyaloid to vitreous pro- lapse to extraocular vitreous loss. Re- tained lens material may further complicate matters. Satisfactory res- olution and prognosis requires an individualized approach that, if ap- propriately handled, can maintain excellent chances for an optimal outcome even if a second surgery should occur for retained lens mate- rial. Complication control Vitreous follows a gradient from high to lower pressure. When suspi- cious of a complication, surgeons should seek a static environment by filling the anterior chamber with dispersive viscoelastic (OVD) through the side port to avoid ante- rior chamber collapse when remov- ing instruments from the main incision. Surgeons can then safely inspect and plan. Whenever possible, convert rents of any shape to a continuous rhexis (PCCC). Push the hyaloid face posteriorly and protect with OVD for subsequent maneuvers. Seal the posterior segment by implanting a three-piece IOL with haptics in the bag and optic captured through an adequately sized PCCC. Ignore OVD behind the IOL. OVD anterior to the lens can be efficiently removed without representation of vitreous. If the hyaloid is breached, our EW NEWS & OPINION 15 Performing the vitrectomy using proper machine settings Source: Lisa B. Arbisser, M.D. goals include limiting vitreous travel, removing the least amount necessary so none is left above the level of the posterior capsule, and limiting collateral damage. Identify- ing nearly invisible vitreous with Triesence (triamcinolone acetonide injectable suspension, Alcon, Fort Worth, Texas) is helpful in defining the endpoint of removal and warn- ing of representation. Except for a small wisp sharply cut with intraocular scissors and teased back into the posterior seg- ment with OVD, automated vitrec- tomy is appropriate. The cellulose sponge technique many of us learned creates traction both by cap- illary action and by lifting. Sweeping the incision to disengage vitreous from the wound, another historical maneuver, also creates huge trac- tional force through the pupil, which transfers to thin peripheral retina. Performing the vitrectomy Older machines may feature a coax- ial sleeve over the vitrector; how- ever, current technique mandates the biaxial approach. Anterior seg- ment surgeons should irrigate through a clear corneal side-port in- cision or chamber maintainer and not coaxially with the vitrector or through a pars plana incision. Introduce the vitrector through a snug separate clear corneal para- centesis or an MVR or trochar pars plana incision 3.5 mm posterior to the limbus. The pars plana approach is more efficient, less likely to en- gage the capsule or iris, and better amputates a sheet of vitreous to the wound from its posterior connec- tion. The pars plana approach en- courages vitreous back, removing less, and, because it creates lower pressure in the posterior segment, better discourages representation of vitreous during subsequent maneu- vers. I prefer a clear corneal incision mainly when the pupil view is ob- scured. Trochars permit two-plane circumferential sutureless sclero- tomies but require more pressure to insert than sharp MVR entry; they are best employed only when inci- sions are watertight and eyes are normotensive. Always avoid the main clear corneal-sleeved phaco in- cision, which allows vitreous to es- cape around the bare vitrector. Anterior segment surgeons should strive to learn to safely make and close pars plana sclerotomies be- cause of the many advantages. During vitrectomy the foot pedal is always set so foot position (FP) 1 initiates irrigation, FP 2 cut- ting, and FP 3 vacuum. Though this FP order can be reversed when fol- lowability is desired, as with cortex removal, the vitrector must always be cutting when sucking vitreous or continued on page 16