Abstract
Abstract: :
Purpose: To report a pilot surgical experimental study of silicone-assisted guarded filtration procedure (SGFP) designed to mechanically prevent tissue adherence, scarring and resulting filtration failure, without the use of antimetabolites. Methods: We performed filtration surgery in 14 nonglaucomatous eyes of 7 albino rabbits. In all 7 right (study) eyes we performed SGFP, that is, a guarded filtration procedure (GFP, trabeculectomy) with implantation of a 100 µ thick implantable-grade silicone sheet. This implant extended from the posterior sclerectomy edge under the scleral flap, to several millimeters posterior and lateral to the scleral flap, under the conjunctiva and tenon's capsule. We performed a GFP alone (without a silicone implant) in all 7 left (control) eyes. Antimetabolites were not used in any eye. During the post-operative follow-up, we graded conjunctival hyperemia and chemosis, anterior chamber reaction and lacrimation. At the end of the follow-up period, 14-91 days following surgery, intraocular pressure (IOP) was measured with a Tonopen and the rabbits were sacrificed. Results: All 7 (100%) study eyes (SGFP, GFP with silicone implant) demonstrated a bleb at the end of the follow-up period, compared to only 1 of 7 (14.3%) control (GFP alone) eyes (p=0.001). IOP was lower in the study eyes compared to control eyes (8.3±1.8 mmHg vs. 10.6±1.3 mmHg, p=0.047). Hyperemia and chemosis scores were lower in the study eyes compared to control eyes (Hyperemia: 0.94±0.74 vs. 1.33±0.86, p=0.001; Chemosis: 0.561±0.50 vs. 0.77±0.57, p=0.004). Anterior chamber reaction and lacrimation scores were similar in study and control eyes. Conclusion: Silicone sheet implantation significantly increases GFP success rate (without antimetabolites), while reducing conjunctival inflammatory response, in albino rabbits. If also proven successful in human eyes, and as a potential alternative to the use of antimetabolites, SGFP may help reduce long-term postoperative blebitis and endophthalmitis rates to those of the pre-antimetabolites era.
Keywords: 631 wound healing • 601 trabecular meshwork • 316 animal model