OCT 2012

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

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82 EW CORNEA October 2012 Picking up the pieces after dropped DSAEK by Maxine Lipner Senior EyeWorld Contributing Writer A patient with corneal decompensation, aphakic and a fixed, dilated pupil following blunt trauma to the eye. This patient is at risk for posterior dislocation of a DSAEK lenticule How to best handle a posterior dislocation I n recent years DSAEK has gained favorite procedure status with many practitioners for the replacement of the en- dothelium for conditions that involve endothelial disease, accord- ing to Sonia H. Yoo, M.D., professor of ophthalmology, Bascom Palmer Eye Institute, Miller School of Medi- cine, University of Miami. As with any procedure, however, there can be a downside. One fortunately rare complication, dubbed dropped DSAEK, can have a potentially dev- astating outcome. In the April issue of the American Journal of Ophthal- mology, Dr. Yoo and others offered their experiences and gave the heads up on what can be done to prevent this phenomenon from occurring. Dropped DSAEK is a condition in which aphakic patients, who don't have the benefit of the barrier of a lens between the anterior and posterior segments of the eye, are at risk. With this complication the donor graft dislocates into the poste- rior segment. "The setup is that you have a unicameral eye," Dr. Yoo said. "Holding the DSAEK donor tissue in place requires a certain amount of elevation of intraocular pressure, so it can be difficult at times to main- tain the pressure at a high enough level to keep the donor button at- tached in patients who are aphakic." This is particularly true, she finds, for aphakic patients who have had trabeculectomies or who have tubes for glaucoma. While this can occur intraopera- tively, it is more likely for the donor tissue to dislocate later. "There is some rate of dislocation anyway in otherwise uncomplicated cases, and because the patient is lying on his back and there is no barrier in apha- kic patients, it seems like the donor tissue that dislocates does have a risk of going posteriorly," Dr. Yoo said. While all the scenarios were differ- ent in the eight dropped DSAEK cases explored in the recent study, there was one common theme, Dr. Yoo found. "These were all patients who were aphakic who were having their lenses removed at the time of surgery," she said. Making the catch Ensuring that this does not happen begins by being aware of it. Dr. Yoo recommended keeping in mind the possibility of dropped DSAEK, particularly in those with risk fac- tors. There are also steps that can be taken to potentially lower the risk. "There have been some techniques described like putting a cerclage across the pupil, a temporary suture to act as a trap across the pupil until the DSAEK surgery is done, and then removing the cerclage at the end of the case," Dr. Yoo said. Another possibility is to try to build a barrier with viscoelastic. "Using higher mo- lecular weight viscoelastic to block the pupil during the case can some- times be effective," Dr. Yoo said. "But again if you have a vitrec- tomized eye that's aphakic, some- times the viscoelastic will drop down under the pupil and not be as helpful as you would think." A patient with traumatic aphakic and early corneal edema is also at risk for posterior dislocation if DSAEK is performed Source: W. Barry Lee, M.D. Team treatment approach In instances where, despite a practi- tioner's best efforts, this does occur, Dr. Yoo recommended calling in a retinal specialist. "I think that these cases necessitate getting your retina partner into the case because there is invariably vitreous that is back there entangled with the DSAEK donor tissue," Dr. Yoo said. "It does require the retina team to come in and vitrectomize the eye and carefully remove the DSAEK donor tissue or elevate it back into the anterior segment of the eye." Many practitioners wonder about the urgency of this. "I think some of the cases have shown that it is posterior dislocation DSAEK grafts that can cause a fibrotic reaction in even focal tractional retinal detach- ment in the location where they ad- here," Dr. Yoo said. "While it's not an emergency, it's probably better to remove these dislocated donor buttons sooner rather than later." The quality of the tissue may also be compromised as a result of the dislocation. Dr. Yoo urged practi- tioners to use new tissue when possi- ble. "Usually the donor tissue has gone through quite a bit of iatro- genic trauma by that time, so ideally if you had another donor tissue available, I would recommend using a new donor," Dr. Yoo said. She acknowledged, however, that this is a luxury that many may not have. "In that case I think that it would be reasonable to plan to come back another time to replace the donor tissue," she said. So what can patients with this complication expect? Outcomes in the case series of eight varied from no light perception all the way up to 20/30 acuity. The problem in these cases often is retinal detachment. "The risk is that the patient can get a tractional retinal detachment related to the donor tissue adhering to the retina causing focal areas of fibro- sis," Dr. Yoo said. "Some say it's somewhere in the periphery, and we can just leave it and place a new donor button, but I think because of the risk of retinal detachment, it is better to remove that tissue." Overall, Dr. Yoo hopes that prac- titioners come away from the case series with a heightened awareness that although rare, posterior disloca- tion does occur and can be associ- ated with serious complications. However, when handled promptly, patients can ultimately fare well. "Assuming that you can retrieve the DSAEK donor tissue and transplant the new endothelial donor button, I think that the patient still has a reasonably good prognosis," Dr. Yoo said. EW Reference Afshari NA, Gorovoy MS, Yoo SH, Kim T, Carlson AN, Rosenwasser GO, Griffin NB, McCuen BW 2nd, Toth CA, Price FW Jr., Price M, Fernandez MM. Dislocation of the donor graft to the posterior segment in Descemet's stripping automated endothelial keratoplasty. Am J Ophthalmol. 2012 Apr;153(4):638-42, 642.e1-2. Editors' note: Dr. Yoo has no financial interests related to this article. Contact information Yoo: 305-326-6322, syoo@med.miami.edu

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