Cannula-Assisted Technique to Unfold Grafts in Descemet Membrane Endothelial Keratoplasty

Purpose: To describe the use of irrigating single-port cannulas to unfold Descemet membrane endothelial keratoplasty (DMEK) grafts when traditional tapping techniques are challenging. Methods: This study is a retrospective, comparative, nonrandomized, interventional case series that includes 143 DMEKs performed between February 2014 and November 2015. All eyes were divided into 2 groups: in one group, there were 48 cases that underwent DMEK using tap techniques only (Tapping DMEK group), and in another group, there were 30 cases in which irrigating cannulas were used to unfold the graft as a secondary approach (Cannula DMEK group). Intraocular manipulation time and total graft manipulation time were assessed. Uncorrected visual acuity, best spectacle-corrected visual acuity, and endothelial cell count were evaluated at 6 and 12 months postoperatively. We also reviewed DMEK procedures performed between December 2015 and January 2017 to evaluate the use of irrigating cannulas to unfold the graft. Results: All grafts were clear. There was a statistically significant improvement in uncorrected visual acuity and best corrected visual acuity at 6 and 12 months postoperatively in both groups (P < 0.01). Endothelial cell loss was 32.10% and 32.11% at 12 months in the Cannula and Tapping DMEK groups, respectively (P > 0.05). Total graft manipulation time was 3 minutes 40 ± 22 seconds in the Cannula DMEK group and 3 minutes 07 ± 26 seconds in the Tapping DMEK group (P < 0.01). Irrigating cannulas were used as a secondary approach in a smaller percentage of cases between December 2015 and January 2017 (26.2%) compared with DMEK performed during this study (38.5%). Conclusions: When it is difficult to unscroll the endothelium–Descemet membrane graft using only tap techniques, the use of Sarnicola cannulas is useful and effective without negatively affecting the postoperative endothelial cell count.