Structural & functional rehabilitation in eyes with lamina resorption following MOOKP--can the lamina be salvaged?

Purpose: To describe a new technique and analyze the outcome of procedures performed for anatomic and functional rehabilitation in eyes with lamina resorption following the modified osteo-odonto keratoprosthesis (MOOKP) procedure.

Design: Retrospective case series.

Patients & Methods: Eighteen eyes were noted to have lamina resorption of the 85 eyes that underwent the MOOKP surgery over the last 10 years. Further intervention to salvage the globe, and therefore the visual potential, was possible in only 11 eyes, of which two are yet to undergo further intervention. Two patients who had undergone the procedure elsewhere also presented to our centre with evidence of resorption. In all, 11 eyes (nine operated at our centre, two operated elsewhere) were included in this study. Bone morphogenetic protein (BMP) was used alone or along with mandibular cancellous bone within the fibrovascular capsule of the osteo-odonto alveolar lamina, in an effort to prevent further resorption and promote bone generation in areas of resorption in ten eyes. In three of these eyes, there was a continued progression of resorption requiring lamina removal. In these three eyes and another eye with extrusion of the cylinder from the eye, the Lucia Type 2 keratoprosthesis was performed for visual rehabilitation (four eyes).

Results: The BMP procedure was performed in ten eyes. Continued resorption with need for further rehabilitative surgery in the form of Lucia Type 2 Kpro was required in three of these eyes. Of the four patients who had the Lucia Type 2 Kpro, visual acuity improved to better than 20/200 in three eyes over a mean follow-up period of 3 months. Of the remaining seven eyes that had the BMP procedure performed, all have remained stable with respect to anatomic integrity of the lamina and globe, with maintenance of or improvement in pre BMP visual acuity over a mean follow-up of 9.2 months. No other complications of the procedure were noted.

Conclusion: Resorption of the lamina in MOOKP can be addressed by reinforcing the same with BMP in eyes where the cylinder mobility is not significant, as a means to prolong the longevity of the existing lamina. The Lucia Type 2 Kpro might also have a role to play in the functional rehabilitation of eyes with severe lamina resorption or cylinder extrusion if preparation of a new lamina cannot be performed for various reasons.