Evaluation of Total Donor Endothelial Viability After Endothelium-Inward Versus Endothelium-Outward Loading and Insertion in Descemet Membrane Endothelial Keratoplasty

Abstract

Purpose: This study compares endothelial cell density (ECD) and viability between 2 different techniques used to prepare and insert Descemet membrane endothelial keratoplasty (DMEK) donor tissues. The first technique uses the naturally forming Descemet membrane (DM) scroll where the endothelial cells face outward; in the second technique, the DM is folded into thirds (trifold) with the endothelial cells facing inward. Methods: Eighteen cadaveric corneas from 9 donors (matched pairs) were used to compare the 2 tissue-insertion techniques. In the scroll, endothelium-outward technique, standard DMEK preparation was used, and the naturally forming DM scroll was inserted into a Geuder Cartridge. In the trifold, endothelium-inward technique, DMEK preparation was undertaken by folding the donor tissue into thirds before being pulled into the EndoGlide Ultrathin. In each case, the tissue was injected onto a glass slide. Endothelial cell counting was performed using microscopy preinjection and postinjection, and vital staining using calcein acetoxymethyl (AM) was used for quantitative cell viability analysis across the whole tissue. Results: Manual ECDs using direct microscopy did not demonstrate a statistically significant difference in ECD between the 2 injection techniques. Using vital staining of the entire 8.0-mm diameter tissue, there was a significantly higher percentage of viable cells using the trifold, endothelium-inward technique (63.1%) compared with the scroll, endothelium-outward technique (41.5%) (P = 0.013). There was no difference in the pattern of cell loss between the 2 groups. Conclusions: Greater endothelial cell viability was observed using the trifold, endothelium-inward technique compared with the scroll, endothelium-outward technique.

Three-Year Outcomes of Tri-Folded Endothelium-In Descemet Membrane Endothelial Keratoplasty With Pull-Through Technique

“…5 In an attempt to overcome these issues, methods involving the preparation of tri-folded endothelium-in donor tissue were proposed. 5,6 Ex-vivo and early clinical outcomes for endothelium-in methods were comparable to those for endothelium-out DMEK, [7][8][9] but no longer-term data is currently available. Thus, we present herein the 3-year outcomes of tri-folded, endothelium-in DMEK using contact lens-assisted bimanual pull-through delivery technique in eyes with different surgical indications.…”

Comparison of the Modified Jones Tube Technique and the DMEK EndoGlide Technique With and Without Viscoelastic Material for DMEK Tissue Preparation

“…6 A direct comparison of endothelial cell loss using the endothelium-in EndoGlide Ultrathin technique without a stromal scaffold versus the endothelium-outward Geuder cartridge technique (Geuder AG, Heidelberg, Germany) resulted in 41.5% ± 8.9% endothelial cell loss versus 63.1% ± 24.9% ( P = 0.013) in an ex vivo study. 7…”

“…6 A direct comparison of endothelial cell loss using the endothelium-in EndoGlide Ultrathin technique without a stromal scaffold versus the endothelium-outward Geuder cartridge technique (Geuder AG, Heidelberg, Germany) resulted in 41.5% 6 8.9% endothelial cell loss versus 63.1% 6 24.9% (P = 0.013) in an ex vivo study. 7 Later, the Coronet DMEK EndoGlide was developed and resulted in ex vivo endothelial cell loss of 9.2% 6 7.0% versus 11.3% 6 3.0% using the Geuder technique (P = 0.07) 3 and an endothelial cell loss of 33.6% after transplantation at 6 to 11 months follow-up. 8 Our DMEK preparation techniques resulted in overall similar ex vivo endothelial cell loss percentages as the previous DMEK EndoGlide study versus the Geuder study, 3 indicating that both endothelium-out Geuder and modified Jones tube techniques remain comparable to the endothelium-in DMEK EndoGlide for endothelial cell loss attributable to the tissue preparation, storage, and deployment processes.…”

Descemet membrane endothelial keratoplasty: Update on preoperative considerations, surgical techniques, and outcomes

“…[ 47 ] The author emphasizes that the endothelium-in configuration during insertion decreases cell loss; however, another study comparing endothelium-in with endothelium-out insertion of DMEK graft revealed similar outcomes with either of the techniques. [ 42 ] In another ex vivo study by Chong et al ,[ 48 ] greater endothelial cell viability was noted with the endothelium-in technique compared to the endothelium-out technique. The timing of preloading of the graft into the device is having a significant bearing on the scrolling tendency of the DMEK graft.…”