JUN 18, 2008
By Bennie H. Jeng, MD
Cornea/External Disease
The authors of the current study evaluated explanted Descemet membranes from previously failed Descemet membrane endothelial keratoplasty (DMEK) surgeries to determine the causes of primary failure. Based on the fact that all but two of the 11 explanted grafts had endothelial cell densities greater than 1700 cells/mm2, the authors suggested that graft failure after DMEK may not be a result of tissue damage during surgery.
Graft failure had been suspected in these 11 cases, which were part of a larger DMEK study, when the transplanted corneas did not clear within one week after surgery. A subsequent Descemet stripping endothelial keratoplasty (DSEK) was performed on each case two to five weeks after DMEK surgery, with low endothelial cell density considered a marker of DMEK-induced tissue damage. Using video analysis and light microscopy, the authors found that three of the grafts may have been positioned upside down, three may have failed due to excessive tissue manipulation, and one could not be properly attached to the recipient's posterior stroma following vitrectomy due to insufficient air support. The cause of graft failure, defined as lack of clearance of the host cornea three to four weeks after surgery, remained undetermined in four eyes.
The current study suggests that in the early postoperative period detached DMEK grafts can be managed by repositioning and corneas that fail to clear can be observed for spontaneous resolution of corneal edema, much like in Descemet stripping automated endothelial keratoplasty (DSAEK).
In the last decade, selective transplantation of corneal endothelial cells, along with some posterior stromal tissue, has become widely popularized, with various surgical techniques evolving rapidly. DMEK is yet another technique of selective endothelial transplantation, but it only involves the transplantation of Descemet's membrane with the endothelial cells. The procedure is not as popular as DSAEK but definitely shows promise.
Financial Disclosures
Dr. Jeng has no financial interests to disclose.