Treatment of retinal detachment with an encircling band and buckle implant: A comparative pilot study between poly (styrene-b-isobutylene-b-styrene) (SIBS) and trimethyl terminated polydimethylsiloxane (PDMS)

Purpose: To demonstrate the biocompatibility of SIBS implants as compared to PDMS implants in the treatment of retinal detachment in New Zealand White (NZW) rabbit model.^1-2 Introduction: Scierai encircling bands, fixation rings and buckles are utilized for closure of retinal breaks and retina reattachment. The PDA approved PDMS-implant is associated with several post-operative complications, involving thick-fibrotic encapsulations. SIBS, an elastomeric triblock copolymer, was recently PDA approved for use in a cardiovascular drug eluting stent (TAXUS™, Boston Scientific Corp., MA) and showed excellent biocompatibility and slow drug release capability. Materials and Methods: SIBS (9-mol%-styrene) implants were fabricated (InnFocus LLC, USA) to match PDMS implants (Labtician, Inc, Canada) dimensions. 5 NZW rabbits received SIBS and 4, PDMS-implants. Post-operative exam sequence: day 1 and 2, week 1, 2, 3, 4 and 6, and monthly thereafter for up to 1 year. Anatomohistopathology exams sequence: one SIBS animal at 6 weeks and one animal of each treatment group at 3 and 6-months, and two at 12-months. Results: SIBS compared to PDMS animals exhibited less inflammation and a better buckling effect during the first 6 weeks. At POD 9 months, the conjunctival injection in the SIBS rabbit was none as opposed to the PDMS value and the buckling effect for both groups were equal. There were no visible signs of encapsulation with SIBS. There were no infections in the 9 animals and none of the implants extruded thus far (<10 months). Conclusion: SIBS encircling bands, sleeves, and buckle implants are well tolerated in the rabbit model.