title: Outcomes of Boston keratoprosthesis implantation for failed keratoplasty after keratolimbal allograft.
abstract: OBJECTIVE
  To evaluate factors that contribute to keratoplasty failure after keratolimbal allograft (KLAL) and report the outcomes of Boston keratoprosthesis type I (KPro) as salvage therapy.
  
  
  METHODS
  Retrospective noncomparative case series of 7 eyes in 7 consecutive patients with ocular surface disease and limbal stem cell deficiency treated with KPro after failed KLAL. Mechanisms of graft failure, KPro device retention rate, and preoperative and postoperative best-corrected visual acuities were studied.
  
  
  RESULTS
  In the studied cohort, keratoplasty graft failure occurred at an average of 9.9 months (range, 1-17 months) after KLAL. Among the 7 eyes reviewed, 4 had tube shunts, 3 of which contributed directly to endothelial graft failure. One eye failed due to fungal keratitis, 1 eye failed due to immune-mediated endothelial rejection, and 2 eyes failed due to recurrent surface disease. During an average follow-up of 585 days (19.5 months) after KPro, best-corrected visual acuity improved from a median of counting fingers CF@2ft (range, hand motions to 20/400) to a median of 20/400 (range, CF@3ft to 20/25). There was 85.7% (6 of 7) retention of implanted devices at the last follow-up, with 1 eye requiring repeat KPro for corneal melt and implant extrusion after abrupt cessation of immunosuppression.
  
  
  CONCLUSIONS
  Despite successful KLAL outcomes and systemic immunosuppression, patients who undergo ocular surface reconstruction with KLAL are still at risk for subsequent keratoplasty failure. Keratoprosthesis is a viable salvage therapy for visual rehabilitation in these patients. Adequate immunosuppression is important in postoperative management of these patients.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA. jhou.jhh@gmail.com
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Hou
authors.forename: Jose
authors.initials: J
authors.lastname: de la Cruz
authors.forename: Ali R
authors.initials: AR
authors.lastname: Djalilian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001187:Artificial Organs; D002648:Child; D003315:Cornea; D003316:Corneal Diseases / Q000601:surgery*; D005260:Female; D006085:Graft Survival; D006801:Humans; D015948:Keratoplasty, Penetrating; D016850:Limbus Corneae; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D016879:Salvage Therapy; D014184:Transplantation, Homologous; D017211:Treatment Failure; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult