OCT 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/87458

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Page 102 of 168

100 EW RESIDENTS October 2012 Cataract M&M rounds Lots of lens left Questions for the case How can we prevent post-occlusion surge? What are our options to proceed now with vitreous prolapse and lots of lens material behind the Malyugin ring? T he case had gone smoothly but got bad quickly. The patient had a history of tamsulosin use so a Malyugin ring was placed. The rhexis was completed and continuous. The resident struggled a bit with nucleofractis and eventually the posterior capsule was injured while removing a quad- rant due to post-occlusion surge. We noticed the problem only after we realized that we could not spin lens material as easily. Even- tually we noted the capsular tear across from the phaco needle (Figure 1). We immediately placed some dispersive and viscous viscoelastic into the area of the tear and removed the phaco needle to try to maintain the cham- ber. A Weck-Cel confirmed that vitreous was coming to the wound (Figure 2). More than half of the dense lens material remains and the vitreous has prolapsed forward. Thomas Oetting, M.D., Cataract M&M rounds editor rePlay online content pulse modulation of phacoemulsifi- cation decreased post-occlusion surge as the nuclear fragment was maintained near the tip without occlusion. An ABS phaco tip (Alcon, Fort Worth, Texas) was another innovation that prevented surge by allowing flow through a bypass (drilled into the side of the phaco needle) once it was occluded at the tip. Fortunately, post-occlusion George Beiko, M.D. Associate professor, McMaster University St. Catharines, Canada View a video of this case at EyeWorld rePlay Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) Dr. Beiko: Previously, chamber stability was a huge problem when using phacoemulsification to re- move a cataract. When a nuclear fragment became impaled onto the phaco needle, complete occlusion of the tip would result in a rise in vac- uum to a preset maximum. If non- compliant aspiration tubing was used, the high vacuum would cause the tubing to collapse. As the frag- ment was emulsified, eventually a break in the occlusion would occur, the high vacuum and the expansion of the tubing would result in rapid aspiration of the fluid from the anterior chamber, which usually was not replaced by inflow, and shallow- ing of the chamber would occur. It was a common occurrence for the phaco tip to then engage the poste- rior capsule and to cause a rent and vitreous loss. In order to minimize post-occlu- sion surge, numerous strategies were employed. One technique was to maintain a high flow into the eye by using an anterior chamber main- tainer and/or raising the infusion bottle as high as possible; even ex- tension poles were utilized. Another strategy was to employ a second instrument in the eye, such as a Sinskey hook or cyclodialysis spat- ula, to hold the posterior capsule away from the phaco tip. Also, phacoemulsification in the anterior chamber was used, but this ran the risk of damage to the iris and en- dothelium. The introduction of breaks resulting in surge and shal- lowing of anterior chamber are less of a problem with recent innova- tions in phacoemulsification machines. These innovations have included software modifications that monitor chamber stability, micropulse modifications of pha- coemulsification energy, low-com- pliance tubing, and mechanical flow restrictors in the aspiration tubing. Despite these innovations, I still use a second instrument in the eye during phacoemulsification. My pre- ferred instrument is a custom made irrigation handpiece, 19 G, with a Sinskey hook at the tip. I routinely use bimanual small incision surgery with the irrigation handpiece in my left hand and the sleeveless phaco needle in the right hand. The irriga- tion handpiece is placed posterior to the fragment being emulsified, with the irrigation inflow directed toward the posterior capsule. If surge or chamber instability occurs, the inflow of fluid keeps the capsule from coming forward and the Sinskey hook provides a mechanical barrier to contact with the posterior capsule by the phaco tip. The case presented is a chal- lenge; the goal is to remove the remaining nuclear remnant without further compromising the posterior capsule. The Malyugin ring would be left in place and mobilized with a Sinskey hook, as needed, to get visu- alization of the lens fragment during the procedure. Initially, the vitreous prolapse into the anterior chamber should be addressed. A dry vitrec- tomy with frequent refilling of the anterior chamber with balanced salt solution would be my approach, as I am comfortable with this. Once the vitreous was removed, a dispersive OVD would be placed into the region of the posterior capsular tear and under the cornea to copiously coat the endothelium. I would then use a cohesive OVD to viscodissect the remaining fragment from the posterior capsule and to elevate it into the anterior chamber. The next step is to prevent the fragment from dislocating into the vitreous cavity and the vitreous from coming forward. Ideally, if the anterior capsulorhexis is still intact, I would place a three-piece intraocular lens (Sensar or Clariflex, Abbott Medical Optics, Santa Ana, Calif.) into the sulcus to accomplish this. If there was compromise of the ante- rior capsule and a lens could not be placed, I would use a Sheet's glide cut to size, placed anterior to the iris and behind the elevated nuclear fragment. Low flow, low vacuum parameters would be used to emul- sify the fragment. Then, cortical cleanup would be performed using bimanual anterior vitrectomy. If a Sheet's glide was used, this would be removed. If a sulcus intraocular lens was used, it would be elevated into the anterior chamber. I have my vitrectomy foot pedal set for irrigation in position one, aspiration in two, and vitrec- tomy in three. The custom irrigation Sinskey hook handpiece (described above) would be used to manipulate the Malyugin ring for visualization and to keep the IOL away from the vitrectomy tip. The cortex would be removed by using a combination of aspiration to peel it away from the capsule and vitrectomy to cut it. Since I use a bimanual technique, subincisional cortex is usually not an issue. Once the capsule was cleaned of cortex, triamcinolone injected into the anterior chamber would be used to ensure that no further vitreous was present. If any was present, a vitrectomy would be performed. Intraocular lens placement would be dependent on the state of the capsule. A three-piece intraocu- lar lens would be my choice for most outcomes in the type of case pre- sented for discussion. If only a small portion of the posterior capsule has been violated, the intraocular lens could be placed into the bag and rotated so that the haptics are sup- ported by the intact capsule. Alter- natively, the lens could be placed into the sulcus with optic capture by the anterior capsulorhexis. If a significant loss of the capsule is

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