A minimally invasive approach to sub-conjunctival outflow: 1 year results of an ab-interno gelatin stent in combination with preoperative MMC injection for the treatment of primary open angle glaucoma.

Purpose To establish the safety and efficacy of an ab-interno gelatin stent, as a stand-alone procedure, in combination with a preoperative mitomycin C injection in reducing IOP and anti-glaucoma medications in patients presenting with primary open angle glaucoma. Mean IOP, IOP change, reduction in medications, and safety were recorded in 70 subjects through 12 months. Methods In this prospective, non-randomized, multi-center evaluation, safety and efficacy parameters were evaluated. As a stand-alone glaucoma procedure, a trans-scleral gelatin stent is placed through a clear corneal incision using a preloaded injector with a 27 gauge needle. Once in place, the permanent gelatin implant is designed to connect the anterior chamber to the non-dissected Tenon's and subconjunctival space, thereby creating diffuse dispersion of aqueous while bypassing potential outflow obstructions. Effectiveness was assessed by comparing medicated baseline IOP and glaucomatous medications to postoperative values through 12 months. Safety was assessed by assessing complications at routinely scheduled exams through 12 months. Results No major adverse events were reported, and 2 patients were converted to a tube shunt at 6 months. The mean preoperative (best medicated) IOP was 23.6 mmHg. The mean postoperative IOPs were: 13.3 mmHg (44% reduction) at 9 months, and 12.6 mmHg (47% reduction) at 12 months. From the preoperative mean of 3.5 (patients not washed out pre-surgery), 9 months medications were reduced by 69% and at 12 months medications were reduced by 66%. No infection, migration or erosion occurred in any patients. Conclusions This 'hybrid system', combining a minimally invasive ab-interno approach with a subconjunctival drainage, provided very satisfactory intra-ocular pressure control after one year with an excellent safety profile. [ABSTRACT FROM AUTHOR]