Positive pressure during penetrating keratoplasty can be solved with a modified graft-over-host technique

Abstract

Purpose: To describe a modified graft-over-host (MGOH) surgical technique which was used to prevent serious complications in cases of positive vitreal pressure during penetrating keratoplasty (PKP) and to compare the endothelial cell density (ECD) loss and clinical outcome between eyes undergoing MGOH or standard PKP.

Methods: In the proposed MGOH technique, the donor graft is sutured over the recipient cornea as soon as signs of positive pressure are noticed, even before cutting the recipient cornea, and the surgery is continued by consecutive cutting of the recipient and continuous suturing of the donor cornea, quadrant by quadrant. Donor grafts were prospectively followed up for the graft clarity, ECD loss and the amount of astigmatism.

Results: Of 220 cases scheduled for standard PKP in years 2009-2011, eight were operated by MGOH technique. Despite the fact that the donor cornea is situated over the recipient almost throughout the whole MGOH procedure, the ECD loss is equal between eyes operated on by MGOH technique and standard PKP, and none of the grafts had primary graft failure. The only disadvantage was an increased amount of astigmatism that was not as significant once the sutures were taken out.

Conclusion: Modified graft-over-host technique seems to be a safe and effective method to prevent complications during PKP complicated by positive vitreal pressure.

Keywords: endothelial cell density loss; keratoplasty technique; penetrating keratoplasty; positive pressure.