Standardized DMEK Technique

Reducing Complications Using Prestripped Tissue, Novel Glass Injector, and Sulfur Hexafluoride (SF₆) Gas

Abstract

Purpose: 

To report low complication rates in Descemet membrane endothelial keratoplasty (DMEK) using sulfur hexafluoride (SF₆) gas, a novel glass injector, and donor tissue prestripped by an eye bank technician.

Methods: 

A standardized technique of DMEK was performed in 80 consecutive Fuchs corneal dystrophy cases using technician-prestripped tissue, a novel glass injector, a modified Yoeruek tap technique, and an SF₆ gas (20% concentration) bubble for prolonged tissue support. Twenty-five donors were premarked with an “S” stamp for intraoperative orientation. Surgery was performed by 2 experienced DMEK surgeons and 2 inexperienced cornea fellows. Complications were recorded, and the percent endothelial cell loss was calculated at 6 months postoperatively.

Results: 

There were 5 cases that received an air bubble injection postoperatively (6% rebubble rate). There were 6 grafts that immediately failed, 2 because of excessive surgical trauma, and 4 because of upside-down graft placement documented by optical coherence tomography. None of the 25 cases with an S stamp failed. Recipient corneas cleared quickly with no clinical evidence of toxicity from the SF₆ gas bubble, and the grafts experienced a mean endothelial cell loss of 27% at 6 months.

Conclusions: 

Tissue prestripped by an eye bank technician can be safely used for DMEK surgery. SF₆ gas for prolonged tissue support may reduce the rebubble rate in DMEK, with no apparent acute toxic effect. An unrecognized upside-down graft was the primary cause of graft failure in this series. Upside-down grafts may be eliminated by the use of donor tissue premarked by the eye bank with an S orientation stamp.