Biodegradable Mechanical Retinal Fixation: A Pilot Study

Mechanical retinal fixation is a useful tool in the armamentarium of vitreoretinal surgeons. Unfortunately, the use of metallic retinal tacks on a permanent basic mandates a retained intraocular foreign body that poses some potential for longrange toxic effects. Herein, we report the results of our initial experience with a temporary, biodegradable mechanical retinal fixation device ("biopin") in rabbits. When compared with metallic tacks, the biopins appeared to be well tolerated intraocularly, with minimal damage detectable at the light microscopic level. Disinsertion of the biopins occurred in 46% of the eyes within two weeks and in all eyes by four weeks. Initial signs of degradation of the biopins were observed at six weeks (median) in the lensectomized/vitrectomized eyes and at 12 weeks (median) in the nonvitrectomized eyes. Differences were found in the occurrence of retinal detachment between animals that underwent lensectomy/vitrectomy with insertion of two metallic tacks and animals that underwent insertion of one biopin without vitrectomy. The biopin has a potential as a vehicle for sustained release of pharmacologic agents to inhibit directly the development of vitreoretinal proliferation, thereby retarding or preventing subsequent retinal traction and detachment.