Novel Trephine for Descemet Membrane Endothelial Keratoplasty Surgery Improves Surgical Preparation Time and Graft Quality: Pilot Data From the “Number 7” Endothelial Keratoplasty Trephine

Abstract

Purpose: To report the safety and efficacy of a novel asymmetric marking trephine for Descemet membrane endothelial keratoplasty (DMEK) tissue preparation. The trephine design incorporates optimized curves to distribute mechanical forces and minimize the risk of tears without loss of total endothelial cell volume transplanted compared with a standard 8.00 mm circular transplant. Methods: A retrospective case series of 40 consecutive DMEK operations comparing 20 cases using the “Number 7” trephine against 20 using a modified shark fin technique as standard. Patient and donor characteristics, tissue preparation time and complications, total surgical time, intraoperative and postoperative complications, and endothelial cell counts at 3 months postsurgery are reported. Results: DMEK tissue preparation was significantly faster using the “Number 7” trephine (5.4 vs. 7.6 minutes, P = 0.008). Further, fewer complications arose during tissue preparation (0 vs. 2 complications) despite the faster preparation time. Total surgical time was similar between techniques; however, time spent manipulating the graft was reduced (5.1 vs. 6.8 minutes, P = 0.007) primarily because of the lower tissue preparation complications. Fewer postoperative complications were observed (1 vs. 3, of which 1 in the standard technique group requiring a redo-DMEK), again due to the reduced tissue preparation complications. The 3-month endothelial cell count was comparable between techniques (P > 0.05). Conclusions: Use of the “Number 7” trephine led to faster and safer DMEK tissue preparation, which in turn reduced graft manipulation times and postoperative complications without compromising total endothelial cell volume transplanted. This novel device is ideal for use by surgeons who prepare their own DMEK tissue and within tissue banks who provide prestripped and preloaded DMEK tissue.