Boston Keratoprosthesis in 2012: preventing complications and optimizing outcomes

Purpose To provide an update on Boston KPro indications, post‐operative care and prevention and management of the complications based upon experience at the MEEI and results presented at the Eighth KPro Study Group Meeting in May 2012. Methods Clinical records were reviewed to determine outcomes of primary KPro surgery and surgery done using backplates of different materials and design. The origin of retroprosthetic membranes (RPM) from 4 explanted KPro’s was determined using immunohistochemistry and light and transmission electron microscopy. Wound anatomy in 6 KPro patients with larger 9.5 mm backplates was evaluated by anterior segment OCT and compared to wound anatomy in patients with standard 8.5 mm backplates. Results Titanium backplates reduce RPM formation. Histopathologic evaluation showed that RPM are fibrous membranes that originate from activated host stromal cells that migrate through gaps in the graft‐host junction, suggesting that better wound apposition may reduce RPM formation. OCT demonstrated that larger backplates clamp the graft‐host junction more effectively than standard backplates, resulting in a thinner graft‐host junction and better wound apposition. Primary Boston KPro surgery provides good outcomes and device retention in situation such as limbal stem cell deficiency where traditional keratoplasty does poorly. Conclusion Indications for the Boston KPro continue to expand as complications are reduced. Primary Boston KPro may be considered in certain circumstances. Strategies for prevention of RPM include titanium backplates and complete apposition of the graft‐host junction using larger KPro backplates.