Expanded polytetrafluoroethylene episcleral implants used as encircling scleral buckling - An experimental and histopathological study

To investigate tissue changes induced by the implantation of expanded polyt etrafluoroethylene (e-PTFE) used as encircling scleral buckling, an experim ental 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 histopath ological study, 2 others were discarded for too short a time of implantatio n and, in 2 additional eyes, the episcleral implant was exposed with a wide conjunctival erosion. Surrounding the implant, a constant encapsulation wa s combined with numerous giant cells, forming a granuloma caused by irregul arities of the implant outline. its porous structure allowed a peripheral c olonization by fibrovascular tissue. Scleral thinning and scleral invaginat ion were the main scleral changes. No change of the conjunctiva made us sus pect that a granuloma occurred before it was found histologically. The gran ulomatous changes did not seem to modify the apparently good experimental t olerance of the material after its implantation. Copyright (C) 2000 S. Karg er AG, Basel.