Abstract
Purpose: :
Descemet Membrane Endothelial Keratoplasty (DMEK) is a novel procedure for transplantation of corneal endothelium resulting in unsurpassed improvement of postoperative visual acuity. A central issue regarding this technique is the complexity of graft preparation which hinders its wide spread use. Therefore, the evaluation of precut tissue for the use of DMEK is essential for making this technique amenable to a larger group of surgeons.
Methods: :
14 human corneoscleral donor buttons not suitable for transplantation which had been organ cultured were used. Following endothelial cell count in group A graft preparation was performed as previously described resulting in a free floating roll of Descemet’s membrane and corneal endothelium (n=7). In group B (n=7) Descemet's membrane was stripped incompletely leaving the graft attached to a central zone of approximately 1 mm2. Both groups were cultured for another 5-6 days followed by endothelial cell count and histological as well as ultrastructural analysis.
Results: :
Both groups did not differ regarding age or endothelial cell count prior preparation. Using a bimanual approach stripping was performed without graft loss. Stripping in goup B was successfully completed shortly before histological analysis by an untrained technician. Moreover, handling was greatly facilitated in group B but endothelial cell count during culturing could only be performed in group A. At the end of the culturing period endothelial cell loss was 624 + 274 cells/mm2 in group A and 357 + 123 cells/mm2 in group B (p<0.04). Histological findings confirmed a confluent layer of corneal endothelial cells in both groups.
Conclusions: :
Coventional graft preparation resulting in complete separation and roll formation is more traumatic than incomplete stripping. The later facilitates handling and transportation. Incomplete graft preparation results in precut tissue suitable for further processing even by unexperienced surgeons and helps to preserve the integrity and the viability of corneal endothelial cells.
Keywords: cornea: endothelium • cornea: storage • cornea: clinical science