Maier Anna-Karina B, Gundlach Enken, Schroeter Jan, Klamann Matthias K J, Gonnermann Johannes, Riechardt Aline I, Bertelmann Eckart, Joussen Antonia M, Torun Necip
Department of Ophthalmology, Charité - Universitätsmedizin Berlin Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany,
Graefes Arch Clin Exp Ophthalmol. 2015 Jun;253(6):895-900. doi: 10.1007/s00417-015-2939-9. Epub 2015 Jan 29.
Descemet membrane endothelial keratoplasty (DMEK) is a standard procedure in patients with endothelial corneal disorders. We investigated the difficulty of unfolding and attaching the graft lamella and its correlation to characteristics of the graft lamella donor, preoperative patient characteristics, and the postoperative outcome.
After preparation of the graft lamella, we prospectively graded the unfolding of the graft lamella in 169 consecutive DMEK procedures between September 2012 and August 2013 at the Charité-Universitätsmedizin Berlin with four different grades. Various donor characteristics and preoperative patient characteristics were analyzed and correlated to the grading. Additionally, visual acuity, corneal thickness and endothelial cell density were measured and correlated.
Donor characteristics (age [range, 49 - 79 years], gender, endothelial cell density, total storage time, storage de-swelling time, postmortem time) did not correlate to the grading. Preoperative visual acuity significantly influenced the grade of unfolding and attaching of the graft lamella (p = 0.023), while all other preoperative parameters (age, gender, indication for DMEK, preoperative endothelial cell density and preoperative central corneal thickness) showed no correlation. Visual acuity improved significantly after surgery (p < 0.001, preoperative 0.73 ± 0.43 LogMAR versus 0.31 ±0.28 LogMAR after one month, 0.25 ± 0.29 LogMAR after three months, and 0.21 ± 0.25 LogMAR after six months). Visual acuity did not differ significantly between the grading groups at any time point postoperatively. After 6 months, the mean loss rate of endothelial cell density was 24.7 %. Grading group IV developed significantly higher endothelial loss after one month, after three months and after six months compared to the other groups (p = 0.039, p = 0.008, p = 0.048). Graft detachment requiring an additional intracameral air injection to fix the graft detachment (re-bubbling) occurred in 61 eyes (38.1 %). In eyes graded IV, more re-bubblings were necessary than in all other groups (grade I: 37.0 %; grade II: 44.7 %; grade III: 43.8 %; grade IV: 50.0 %; p = 0.128; df = 3; χ (2) = 5.676).
There is no correlation between corneal donor tissue characteristics and the degree of difficulty of unfolding using graft lamella older than 49 years. Therefore, it is not possible to select grafts best suited for DMEK surgery on the basis of donor characteristics when the donor age is above 50 years. Preoperative visual acuity influences the grade of difficulty. The rate of graft detachments and endothelial cell loss increases significantly with a more difficult graft unfolding. The proposed grading system may therefore be relevant for postoperative management.
Descemet膜内皮角膜移植术（DMEK）是治疗角膜内皮疾病患者的标准手术。我们研究了移植片层展开和附着的难度及其与移植片层供体特征、术前患者特征和术后结果的相关性。
在制备移植片层后，我们对2012年9月至2013年8月在柏林夏里特大学医学中心连续进行的169例DMEK手术中的移植片层展开情况进行了前瞻性分级，分为四个不同等级。分析了各种供体特征和术前患者特征，并与分级进行相关性分析。此外，测量了视力、角膜厚度和内皮细胞密度并进行相关性分析。
供体特征（年龄[范围，49 - 79岁]、性别、内皮细胞密度、总保存时间、保存消肿时间、死后时间）与分级无关。术前视力显著影响移植片层展开和附着的等级（p = 0.023），而所有其他术前参数（年龄、性别、DMEK适应证、术前内皮细胞密度和术前中央角膜厚度）均无相关性。术后视力显著改善（p < 0.001，术前0.73 ± 0.43 LogMAR，术后1个月为0.31 ± 0.28 LogMAR，术后3个月为0.25 ± 0.29 LogMAR，术后6个月为0.21 ± 0.25 LogMAR）。术后任何时间点分级组之间的视力均无显著差异。6个月后，内皮细胞密度的平均损失率为24.7%。与其他组相比，IV级组在术后1个月、3个月和6个月时内皮细胞损失显著更高（p = 0.039，p = 0.008，p = 0.048）。61只眼（38.1%）发生了需要额外前房内注入空气以固定移植片层脱离（再次注气）的移植片层脱离。在IV级眼中，需要再次注气的情况比所有其他组更多（I级：37.0%；II级：44.7%；III级：43.8%；IV级：50.0%；p = 0.128；自由度 = 3；χ(2) = 5.676）。
年龄大于49岁的角膜供体组织特征与使用移植片层展开的难度程度之间没有相关性。因此，当供体年龄超过50岁时，不可能根据供体特征选择最适合DMEK手术的移植片。术前视力影响难度等级。移植片层展开难度越大，移植片层脱离率和内皮细胞损失率显著增加。因此，所提出的分级系统可能与术后管理相关。
