Endothelial quality of pre-cut posterior corneal lamellae for Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S): two-year outcome of manual preparation in an ocular tissue bank

Abstract

To assess the quantitative and qualitative parameters of pre-cut posterior corneal lamellae for Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S) prepared manually in the Ocular Tissue Bank Prague. All 65 successfully prepared pre-cut posterior corneal lamellae provided for grafting during a 2-year period were analyzed retrospectively. The lamellae, consisting of a central zone of endothelium-Descemet membrane surrounded by a supporting peripheral stromal rim, were prepared manually from corneoscleral buttons having an endothelial cell density higher than 2,500 cells/mm(2). The live endothelial cell density, the percentage of dead cells, the hexagonality and the coefficient of variation were assessed before and immediately after preparation as well as after 2 days of organ culture storage at 31 °C. Altogether, the endothelium of 57 lamellae was assessed. Immediately after preparation, the mean live endothelial cell density was 2,835 cells/mm(2) and, on average, 1.8 % of dead cells were found. After 2 days of storage, the cell density decreased significantly to 2,757 cells/mm(2) and the percentage of dead cells to 1.0 %. There was a significant change in the mean hexagonality and the coefficient of variation after lamellar preparation and subsequent storage. The amount of tissue wasted during the preparation was 23 %. The endothelial cell density of posterior corneal lamellae sent for DMEK-S was higher than 2,700 cells/mm(2) in average with a low percentage of dead cells; 65 pre-cut tissues were used for grafting during a 2-year period.

Risk Factors for Eye Bank Preparation Failure of Descemet Membrane Endothelial Keratoplasty Tissue

“…13,14 However, risk factors for failure in DMEK graft preparation and, consequently, for a higher endothelial cell loss or tissue wastage, have not been addressed in a large-volume, multitechnician eye bank setting and have been limited to surgeon preparation of donor tissue. In this latter context, difficulty in graft peeling for the first eye has been shown to be the most important factor for failure in the fellow eye.…”

Effectiveness of curvilinear approach in dissection of Descemet's membrane: first 500 cases – factors influencing graft preparation

“…The technique of forceps dissection was modified using two forceps simultaneously or using one forceps with curvilinear grasping area, introduced by us ( Kruse et al 2011;Yoeruek & Bartz-Schmidt 2013). Also, precut DMEK was introduced; however, long-term clinical data are missing to compare the results of precut DMEK against standard DMEK procedure (Krabcova et al 2013). Therefore, other techniques were described such as automated donor tissue preparation using a microkeratome, pneumatic or fluid dissection techniques (McCauley et al 2009;Busin et al 2010;Venzano et al 2010;Kymionis et al 2011;Sikder et al 2011;Yoeruek et al 2012).…”

“…Therefore, other techniques were described such as automated donor tissue preparation using a microkeratome, pneumatic or fluid dissection techniques (McCauley et al 2009;Busin et al 2010;Venzano et al 2010;Kymionis et al 2011;Sikder et al 2011;Yoeruek et al 2012). Also, precut DMEK was introduced; however, long-term clinical data are missing to compare the results of precut DMEK against standard DMEK procedure (Krabcova et al 2013).…”

Eye-bank preparation of endothelial tissue

“…The tissue loss rate fell to 5% with experience performing the technique. However, other studies evaluating the DMEK-S technique report a 23% tissue loss rate due to big bubble rupture and failure of big bubble formation [39]. …”