Reduction of Intraocular Pressure Using a Modified 360-degree Suture Trabeculotomy Technique in Primary and Secondary Open-Angle Glaucoma: A Pilot Study

Purpose: To investigate the effects of a modified 360-degree suture trabeculotomy technique for primary and secondary open-angle glaucoma (POAG and SOAG). Methods: We modified the procedure for 360-degree trabeculotomy by using a 5-0 nylon suture, making a scleral flap to allow clear identification of Schlemm canal, and creating a corneal side port incision opposite to the scleral flap to retrieve the suture used to cannulate and cleave the canal. The modified 360-degree suture trabeculotomy (not combined with cataract surgery) was performed on 25 eyes with POAG and 18 eyes with SOAG, and the results were compared retrospectively with those of standard trabeculotomy with metal trabeculotomes (16 eyes with POAG and 19 eyes with SOAG). When the intraocular pressure (IOP) was reduced by 30% from the preoperative IOP and was also below 18 mm Hg at 3, 6, 9, 12, and 18 months after surgery and the patient was taking a similar number or fewer medications, the surgery was considered a "success." Results: Using this modified technique, Schlemm canal was appropriately incised without resistance. At 12 months after the modified 360-degree suture trabeculotomy and trabeculotomy with metal trabeculotomes, the mean postoperative IOP values were 13.1 and 15.2 mm Hg, respectively, and the mean numbers of antiglaucoma medications were 0.5 and 1.4, respectively. The success rates of POAG at 12 months for the modified 360-degree suture trabeculotomy and trabeculotomy with metal trabeculotomes were 84% and 31%, respectively, and those of SOAG were 89% and 50%, respectively. The complications included a transient elevation of the IOP above 30 mm Hg in 22 eyes (47%) treated with the 360-degree suture trabeculotomy and 17 eyes (49%) treated with trabeculotomy with metal trabeculotomes. There was no significant difference between preoperative visual acuity and postoperative visual acuity in either procedure. Conclusions: This modified 360-degree suture trabeculotomy is a feasible surgical option for POAG and SOAG.