Descemet’s Stripping Endothelial Keratoplasty—Insertion Techniques for Endothelial Keratoplasty
among surgeons, but a reasonable starting point is to leave a bubble approximately the size of the donor button. Some surgeons leave a larger air bubble and ‘burp’ the wound to let out some air at the slit lamp after a longer waiting interval. The patient lies in a supine position in the recovery room for 1–2 hours (varies by surgeon) to enable the partial air bubble to continue to tamponade the graft in place (see Figure 5).
Complications
Immediate or peri-operative complications are usually secondary to pressure elevations. Overfill of the anterior chamber typically results in a pressure rise. This is readily managed by an air–fluid exchange or by simply letting some air out of the wound. Of greater concern is secondary papillary block or angle closure caused by air migrating behind the iris. Most surgeons dilate the eye at the conclusion of the case to relieve any trapped air. Repeat applications of both cycloplegics and sympathomimetics might at times be needed. On rare occasions, surgical (laser peripheral iridotomy) intervention might be required.
The exact reason for their decrease in frequency with greater surgical experience remains unknown.4
Partial or complete dislocations are common in early cases, decreasing with increasing experience. The dislocations rates reported in the literature vary from 0–82 % (with an average of 14 %) making their interpretation difficult.1
It is probably related to decreased
endothelial damage with less manipulation, as well as better management of air tamponade and avoidance of hypotony. If the donor button is in a reasonable position, and only partially dislocated, and there is still an air bubble present, the patient should be instructed to remain flat on their back for an additional day. If there is no air bubble present, or if the bubble is so small that it would not tamponade the dislocated area, additional air can be injected. Complete dislocations require a large air bubble, similar to that carried out in documented. Buttons that fail to adhere after repeated attempts (repeat air injection) might have to be replaced because of widespread and irreversible endothelial damage.5
Early reports suggested that there was an accelerated endothelial cell loss with DSEK compared with PK. Larger long-term studies revealed similar rates of cell loss, although the cases were not matched and many surgeons intervene at an earlier stage of endothelial dysfunction than was common with PK.1,2,6
Similarly, graft rejection is hard to compare because of a lack of true case-controlled comparative studies, but
1. Lee WB, Jacobs DS, Musch DC, et al., Descemet’s stripping endothelial keratoplasty: safety & outcomes: a report by the American Academy of Ophthalmology, Ophthalmology, 2009;116(9):1818–30.
2. Price MO, Gorovoy M, Benetz BA, et al., Descemet’s stripping automated endothelial keratoplasty outcomes compared with penetrating keratoplasty from the Cornea Donor Study, Ophthalmology, 2010;117(3):438–44.
appears, at worst, similar to full-thickness PK. Treatment regimens for graft rejection with DSEK do not differ significantly from PK. Irreversible graft failure is treated with removal of the donor lenticule, which typically can be peeled off the patient’s cornea and replaced with a new donor. Data on graft survival for repeat DSEK are lacking.7
Summary
DSEK has emerged as the treatment of choice for individuals with primary or secondary endothelial failure. It affords the patient a faster visual rehabilitation with less induced astigmatism. After an initial learning curve, endothelial survival after DSEK appears comparable to PK. Newer insertion devices, such as glides and inserters, have decreased the learning curve somewhat, but there is no consensus as to the single best surgical technique, and well-controlled studies comparing the different techniques are lacking. As with all surgical procedures, surgeons should observe multiple techniques to determine what best suits their surgical skills, and operating environment. n
3. Bahar I, Kaiserman I, Levinger E, et al., Retrospective contralateral study comparing Descemet stripping automated endothelial keratoplasty with penetrating keratoplasty, Cornea, 2009;28(5):485–8.
4. Terry MA, Shamie N, Chen ES, et al., Endothelial keratoplasty a simplified technique to minimize graft dislocation, iatrogenic graft failure, and pupillary block, Ophthalmology, 2008;115(7):1179–86. 5. Suh LH, Yoo SH, Deobhakta A, et al., Complications of Descemet’s
stripping with automated endothelial keratoplasty: survey of 118 eyes at one institute, Ophthalmology, 2008;115(9):1517–24. 6. Price MO, Fairchild KM, Price DA, Price FW, Descemet’s stripping endothelial keratoplasty five-year graft survival and endothelial cell loss, Ophthalmology, 2011;118(4):725–9.
7. Bahar I, Kaiserman I, McAllum P, et al., Comparison of posterior lamellar keratoplasty techniques to penetrating keratoplasty, Ophthalmology, 2008;115(9):1525–33.
Figure 5: Scheimpflug Image Showing a Well-adhered Descemet’s Stripping Endothelial Keratoplasty Button
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