Comparing two tensioning suture sizes for 360 degrees viscocanalostomy (canaloplasty): a randomised controlled trial.

摘要

PURPOSE: To compare the safety and efficacy of two polypropylene (Prolene) sutures for tensioning of the inner wall of Schlemm's canal (SC) in black African patients with primary open-angle glaucoma (POAG) undergoing canaloplasty. METHODS: In a prospective randomised trial of 90 patients, canaloplasty was performed with a flexible microcatheter (iTrack-250A) and sodium hyaluronidate 1.4% (Healon GV). After complete circumferential dilatation of the SC, a Prolene suture, either 6-0 Prolene (group 1) or 10-0 Prolene (group 2), was retracted through the SC and tightened leaving tension on the canal and trabecular meshwork. Nd:YAG laser goniopuncture was not performed postoperatively. RESULTS: The mean preoperative intraocular pressure (IOP) was 42.7 mm Hg+/-12.5 (SD) in group 1 and 45.0 mm Hg+/-12.1 (SD) in group 2 (P=0.70). The mean postoperative IOP without medications was 18.4 mm Hg+/-7.1 (SD) in group 1 and 16.4 mm Hg+/-6.6 (SD) in group 2 at 1 month (P=0.10), 19.2 mm Hg+/-6.4 (SD) in group 1 and 16.4 mm Hg+/-4.9 (SD) at 15 months (P=0.04). Pressures equal or less than 21, 18, and 16 mm Hg without medications (complete success) at 12 months were 51.0% (95% confidence interval (CI) 0.35-0.73), 34.1% (95% CI 0.21-0.56), and 21.2% (95% CI 0.11-0.42) in group 1, and 76.9% (95% CI 0.62-0.96), 68.8% (95% CI 0.54-0.89), and 53.6% (95% CI 0.38-0.76) in group 2, respectively. In the Cox regression analysis, IOP<18 mm Hg without medications depended significantly on the type of Prolene (hazard ratio (HR) 2.60, 95% CI 1.24-5.46, P=0.01) and age (HR 1.3, 95% CI 1.03-1.86, P=0.03), but not on preoperative IOP (HR 1.01, 95% CI 0.99-1.04, P=0.16) and gender (HR 0.67, 95% CI 0.34-1.33, P=0.26). No filtering bleb was observed. Intra- and postoperative complications were similarly rare in the two groups and included partial 'cheese-wiring' (2), Descemet's rupture (2), and hyphaema (3). CONCLUSIONS: In this clinical trial, IOP reduction was substantial in canaloplasty and slightly greater in combination with 10-0 Prolene than 6-0 Prolene sutures at an equally low complication rate. Younger age, but not the level of IOP at surgery, had a positive effect on the amount of IOP reduction, thus suggesting that an early surgical intervention to re-establish physiological outflow offers the best prognosis.