Abstract
Purpose: :
Devices to avoid wound compression damage in DSAEK surgery are broadly distinguished as platform delivery devices v pull through devices. Controlled laboratory data on total endothelial damage from these devices is scant. We compared the commonly used NCI device (platform) to the Tan Endoglide (pull through) to assess baseline endothelial damage from the single manipulation of loading and unloading of the tissue in the cadaver model.
Methods: :
Pre-cut DSAEK tissue with healthy endothelium was trephinated to an 8.0 mm diameter in 10 donor corneas. Five lenticules were placed onto a NCI platform (Group 1) and 5 lenticules were placed into a Tan Endoglide.(Group 2) Tissues were then delivered into a basin of BSS, stained with vital dye stain to mark endothelial damage, and then digital photographs of the entire endothelial surface were made. Photoshop digitized planimetry was performed to determine percentage of endothelial damage from the trephination and manipulations in each group and distinctive patterns of endothelial damage were recorded. Mann-Whitney U Test was used to compare the means of each group.
Results: :
The mean total percent endothelial damage was 17% +/-5% (range: 11% to 22%) in Group 1 and 32% +/-18% (range: 18% to 63%) in Group 2. (p=.047) Damage from trephination alone was about 10% in tissues of each group. Lenticule thickness ranged between 117 u to 166 um in group 1 and 100 u to 192 u in group 2. Thin tissue made manipulation in both groups more difficult and more traumatic. Eliminating the 100 u tissue of group 2 which rolled in reverse on loading with an outlier damage of 63%, the revised mean endothelial damage was 24% +/-5% in group two, minimizing the difference between the two groups.(p=.11) The pattern of damage in Group 1 was usually along the edges and in Group 2 was central striae associated with the point of grasping.
Conclusions: :
Although delivery devices avoid wound compression, there is still significant endothelial damage from trephination, mounting and dismounting the tissue. A learning curve is important with both devices and thin tissues may make loading both devices more difficult.
Keywords: cornea: endothelium • transplantation • cornea: clinical science