Indications, outcomes, and risk factors for failure in tectonic keratoplasty

Purpose: Outcomes of corneal transplantation for tectonic indications and risk factors for (tectonic and physiologic) graft failure.

Design: Retrospective cohort study.

Participants: Consecutive patients who underwent keratoplasty for tectonic indications at the Singapore National Eye Centre (SNEC) between January 1, 1991, and December 1, 2009.

Methods: Clinical data and donor and recipient characteristics were recorded and analyzed from subjects in the prospective Singapore Corneal Transplant Study.

Main outcome measures: (1) Tectonic (anatomic) failure defined as recurrence of corneal melt threatening tectonic integrity and requiring additional corneal grafting within 3 months of the primary procedure. (2) Physiologic failure defined as irreversible change in graft clarity preventing recovery in useful vision in grafts initially clear 2 weeks postoperatively.

Results: The mean age of the study cohort (n = 362, 193 male and 169 female subjects) was 51.5 ± 20.2 years, with a mean follow-up of 25.8 ± 18.7 months. Patients underwent penetrating keratoplasty (PK) (n = 142, 39.2%), anterior lamellar keratoplasty (ALK) (n = 127, 35.1%), or a peripheral corneoscleral patch graft (n = 93, 25.7%) most commonly for inflammation (n = 68, 18.8%), trauma (n = 66, 18.2%), or infection (n = 66, 18.2%). Risk factors for tectonic failure (18/362 eyes, 5.0%) were severe lid disease (odds ratio [OR], 6.1; 95% confidence interval [CI], 1.7-22.1; P = 0.006), central ALK (OR, 7.5; 95% CI, 1.8-32.4; P = 0.007), and peripheral grafts (OR, 5.7; 95% CI, 1.1-28.3; P = 0.035). Among anatomically successful central grafts (n = 223), the mean physiological graft survival was 96 months (95% CI, 83-110); Kaplan-Meier probabilities for survival at 10 years were 66.8% for ALK and 44.2% for PK. Active corneal inflammation (hazard ratio [HR], 2.5; 95% CI, 1.4-4.4; P = 0.003) and larger donor and recipient graft sizes of ≥ 9 mm (HR, 17.9; 95% CI, 2.3-140.3; P = 0.006) were risk factors for physiologic graft failure in anatomically successful eyes with central tectonic grafts.

Conclusions: Patients with lid disease, central ALK, and peripheral grafts were at higher risk of anatomic failure. For anatomically successful cases with central tectonic grafts, active corneal inflammation and donor size ≥ 9 mm were risk factors for physiologic failure. In these cases, our results suggest that ALK had better physiologic graft survival outcomes than PK.