Expanded Polytetrafluoroethylene Episcleral Implants Used as Encircling Scleral Buckling

Abstract

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.

Comparison of Alloplast Materials in Experimental Extraocular Muscle Surgery

“…The Gore-Tex used in this study has a microporous structure with a pore size of 10-30 m, which also allows tissue ingrowth and cell attachment. The highly porous form exhibits an irregular surface, which facilitates colonization by vascularized connective tissue [20,21] . In this study, the porosity of the Gore-Tex material was less than 50 m, the giant cell formation was not markedly increased.…”

S/e‐PTFE episcleral buckling implants: An experimental and histopathologic study

“…The surgical method has been described in a previous experimental evaluation. 5,6 No indentation effects were desired. The rabbits were sacrificed after 28 -85days (Table I) (mean: 60 days; SD: 27).…”

“…This was also shown in previous studies in which nonabsorbable scleral buckling materials were implanted under the conjunctiva. [5][6][7][8][9][10] These implants induced a chronic inflammation that stimulates the fibroblasts, prompting them to generate a fibrous capsule that finally encases the episcleral implant. At later stages, the capsule completely separates the implant from the surrounding tissues.…”

“…5,6,11 In addition to its probable role of protecting surrounding tissues from the implant, the encapsulation of the episcleral implant may help to reduce the incidence of scleral or conjunctival erosion, implant extrusion, or intrusion and infection. 3,12 In the present study, mean thickness of the fibrotic capsule is thinner than that found in previous studies with e-PTFE, 5,6,11 that is, similar to S/e-PTFE in its external configuration. This can be explained by the short observational period in this study, but also by the fact that only the fibrous component of the capsule was considered here.…”

The Use of Polymers in the Treatment of Retinal Detachment: Current Trends and Future Perspectives

“…Porous expanded PTFE (e-PTFE) was proposed in the form of buckling bands [60][61][62][63][64] or, more recently, as coating on silicone implants [65][66][67] with variable and controversial outcomes. Potentially, the material could be an alternative to silicone, but further studies of its performances and effects in vivo are necessary.…”