title: Indications, outcomes, and risk factors for failure in tectonic keratoplasty.
abstract: OBJECTIVE
  Outcomes of corneal transplantation for tectonic indications and risk factors for (tectonic and physiologic) graft failure.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  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.
  
  
  METHODS
  (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.
authors.affiliation: Singapore National Eye Centre, Singapore.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
authors.forename: Chelvin C A
authors.initials: CC
authors.lastname: Sng
authors.forename: Hla Myint
authors.initials: HM
authors.lastname: Htoon
authors.forename: Donald T H
authors.initials: DT
authors.lastname: Tan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003316:Corneal Diseases / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D016039:Corneal Transplantation; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000453:epidemiology* / Q000209:etiology; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult