When the Keratoprosthesis Is Too Small: Homburger Corneal Gap Bridging Surgical Technique for Combined Vitreoretinal Surgery and Large-Diameter Keratoplasty.

PURPOSE: To describe a new "corneal gap bridging technique" (CGBT) used in eyes requiring a penetrating keratoplasty (PKP) with a trephination diameter >8.0 mm combined with a pars plana vitrectomy (PPV) to allow for the effective application for otherwise unsuitable standard keratoprostheses.

METHODS

A proof-of-concept study in 2 eyes undergoing combined PKP and PPV with corneal gap bridging technique at a tertiary university hospital. The first patient was an 88-year-old woman with infectious keratitis endophthalmitis and the second was a 34-year-old man with peripheral corneal melting and retinal detachment with subretinal proliferative vitreoretinal membrane. An Eckardt-keratoprosthesis was implanted into a donor's corneoscleral disc unsuitable for permanent transplantation because of scarring or reduced endothelial cell counts. After trephination of the host cornea, the disc is fixed to the recipient sclera with interrupted sutures, allowing optimal visualization of the posterior segment during PPV through the now centered keratoprosthesis. After PPV, the disc and prosthesis are removed, and the permanent corneal donor tissue is transplanted as in PKP.

RESULTS

At the last follow-up, both eyes showed a clear graft with attached retina and no signs of recurrent infection.

CONCLUSIONS

The Homburger corneal bridging technique is a viable option to use the benefits of temporary keratoprostheses in eyes requiring a large-diameter PKP with combined PPV. The disc fixation is easy to perform as in PKP without a new learning curve. Further studies are needed to determine whether the improved visualization provided by this approach translates into better long-term functional and anatomical outcomes in eyes with complex pathologies.