Cheung Albert Y, Hou Joshua H, Bedard Peter, Grimes Veronique, Buckman Natalie, Eslani Medi, Holland Edward J
Cincinnati Eye Institute, Department of Ophthalmology, University of Cincinnati, Cincinnati, OH.
Virginia Eye Consultants, Norfolk, VA.
Cornea. 2018 May;37(5):661-666. doi: 10.1097/ICO.0000000000001510.
To describe and report outcomes of our single-pass microkeratome technique for preparation of ultrathin (UT, ≤100 μm) and nanothin (NT, ≤50 μm) Descemet stripping automated endothelial keratoplasty (DSAEK) grafts.
To prepare NT-DSAEK grafts, a pachymetry nomogram specific to each technician and individual microkeratome head was developed based on accumulated precut and postcut pachymetry data from previous DSAEK grafts. Mean graft thickness as well as precut and postcut endothelial cell counts (ECCs) of NT-DSAEK, UT-DSAEK, and Descemet membrane endothelial keratoplasty (DMEK) grafts between July 2015 and July 2017 were calculated and compared statistically. Endothelial cell loss was evaluated using calcein AM stains and ImageJ analysis. Postcut graft thickness and rates of perforation/tissue loss for NT-DSAEK grafts between May and July 2017 were calculated to determine overall graft preparation success rates.
Mean postcut graft thickness for all grafts within the NT range was 41.0 ± 6.4 μm (range 26-50 μm). Mean ECC did not differ between NT-DSAEK, UT-DSAEK, and DMEK grafts (P = 0.759 and 0.633, respectively). The overall tissue loss rate from attempted NT-DSAEK was 4.8%. Excluding cases of perforation, the chance of achieving NT thickness was 60% and within the traditional UT range was 100%.
We propose the term "NT-DSAEK" for grafts ≤50 μm. The described nomogram allows for standardized creation of NT grafts with a low tissue loss rate. This technique is safe and does not result in significant ECC loss compared with UT-DSAEK and DMEK grafts. Further studies are necessary to corroborate the postsurgical results of NT grafts.
描述并报告我们使用单通道微型角膜刀技术制备超薄（UT，≤100μm）和纳米薄（NT，≤50μm）的后弹力层剥除自动内皮角膜移植术（DSAEK）植片的结果。
为制备NT-DSAEK植片，根据先前DSAEK植片的术前和术后角膜厚度测量数据，为每位技术人员和每个微型角膜刀头制定了特定的角膜厚度测量列线图。计算并统计比较了2015年7月至2017年7月期间NT-DSAEK、UT-DSAEK和后弹力层内皮角膜移植术（DMEK）植片的平均植片厚度以及术前和术后内皮细胞计数（ECC）。使用钙黄绿素AM染色和ImageJ分析评估内皮细胞损失。计算2017年5月至7月期间NT-DSAEK植片的术后植片厚度以及穿孔/组织损失率，以确定总体植片制备成功率。
NT范围内所有植片的平均术后植片厚度为41.0±6.4μm（范围26 - 50μm）。NT-DSAEK、UT-DSAEK和DMEK植片之间的平均ECC无差异（分别为P = 0.759和0.633）。尝试进行NT-DSAEK的总体组织损失率为4.8%。排除穿孔病例，达到NT厚度的几率为60%，在传统UT范围内的几率为100%。
我们建议将厚度≤50μm的植片称为“NT-DSAEK”。所描述的列线图允许以低组织损失率标准化创建NT植片。与UT-DSAEK和DMEK植片相比，该技术安全且不会导致显著的ECC损失。需要进一步研究来证实NT植片的术后结果。
