Abstract
Purpose: :
To histologically characterize the host-graft interface of failed DSEK patients and identify factors that may influence graft failure in the postoperative period.
Methods: :
A histologic analysis was performed on 13 corneal buttons obtained at the Emory Eye Center during 2007-2009 that had primary DSEK and subsequently required penetrating keratoplasty. Sections were stained hematoxylin and eosin (H&E) and Periodic acid-Schiff (PAS) stains. The corneal buttons were analyzed by light microscopy to characterize the host-graft interface with attention to the quality of wound healing, and presence of extraneous cellular and acelluar material.
Results: :
Of the initial 13 samples with an intact host-graft interface, 4/13 (30%) exhibited lentiule dislocation from the host stroma. The remaining 9 samples had varying degrees of graft attachment ranging from 30% to 90% lenticule attachment to the host. Each interface was then subdivided and characterized as either "detached" or "attached" and then analyzed for the presence of residual structures that may be related to graft dislocation. The most prevalent findings included host Descement membrane - present in 7/13(54%) of detached interfaces vs. 1/9(11%) of attached interfaces - and epithelial cells - present in 2/13(15%) detached interfaces vs. 0/9 (0%) of attached interfaces. Although all 13 corneal button samples had significant corneal edema, none of the intact wound interfaces - 0/9 (0%) - had host-graft interface fluid present. The primary reason for graft failure and corneal edema for most of the cases - 12/13 (92%) - was due to endothelial cell loss ranging from 0 to 4 cells per high power field.
Conclusions: :
The causal relationship between residual debris (histocytes, reactive keratinocytes) in the host-graft interface and graft dislocation cannot be precisely identified, interface material was present more often in dislocated versus attached interfaces. Additionally, endothelium did not cover the wound edge. The nature of corneal stromal wound healing in DSEK, as evidenced by the lack of interface fluid, is different from the corneal stromal wound healing with LASIK.
Keywords: cornea: basic science • cornea: clinical science • cornea: endothelium