Expanded polytetrafluoroethylene episcleral implants used as encircling scleral buckling. an experimental and histopathological study.

To investigate tissue changes induced by the implantation of expanded polytetrafluoroethylene (e-PTFE) used as encircling scleral buckling, an experimental and histopathological study was performed in rabbits. The eyes of 12 rabbits were implanted during 20-128 days with e-PTFE episcleral implants. Of these, 8 eyes were uncomplicated and enabled us to perform the histopathological study, 2 others were discarded for too short a time of implantation and, in 2 additional eyes, the episcleral implant was exposed with a wide conjunctival erosion. Surrounding the implant, a constant encapsulation was combined with numerous giant cells, forming a granuloma caused by irregularities of the implant outline. Its porous structure allowed a peripheral colonization by fibrovascular tissue. Scleral thinning and scleral invagination were the main scleral changes. No change of the conjunctiva made us suspect that a granuloma occurred before it was found histologically. The granulomatous changes did not seem to modify the apparently good experimental tolerance of the material after its implantation.