Characteristics and Management of Boston Type 1 Keratoprosthesis Explantation: University of Montreal Hospital Center Experience

Saturday, April 18, 2015: 1:56 PM
Room 3 (San Diego Convention Center)
Qianqian Wang, MD
Mona Harissi-Dagher, MD

To describe the characteristics of patients who had Boston keratoprosthesis (KPro) explantation and the outcomes of their subsequent management.

Retrospective observational study. Cases that underwent Boston type 1 KPro at University of Montreal Hospital Center between October 2008 and May 2012 were reviewed. Patients with KPro explantation (n=11) were identified and compared to those with KPro retention (n=99). Visual acuity, expressed as LogMAR, was followed as primary outcome. A value of p<0.05 was considered significant.

The analysis included a total of 345.1 life-years of device implantation. Among 110 operated eyes, 11 eyes had KPro explantation, corresponding to a failure rate of 0.03/life-year. KPro was explanted at 19.7±10.5 (4-40) months post-KPro. Indications included sterile keratolysis (n=7), infection (n=2), hypotony and painful blind eye (1 each). Compared to patients with KPro retention, those requiring KPro explantation were associated with aniridia (p=0.0038), sterile keratolysis (p<0.001), retroprosthesis membrane (p=0.02) and intraocular inflammation (p=0.04). KPro exchange (n=8), penetrating keratoplasty (n=1) or evisceration (n=2) were performed as a secondary intervention. Among patients with KPro explantation, 4 (36.4%) recovered better than baseline visual acuity at final visit. Posterior segment complications (n=5, 62.5%) were the most common cause of permanent vision loss. Final visual prognosis correlates with pre-explantation visual function (r=0.68, p=0.02).

Boston KPro explantation is a serious complication. Aniridic eyes are at significant risk and have a shortened keratoprosthesis retention time. When managed appropriately, patients can recover significant vision.