Efficacy of bleb‐independent penetrating canaloplasty in primary angle‐closure glaucoma: one‐year results

Abstract

Purpose: To report the efficacy and safety of bleb-independent penetrating canaloplasty in the management of primary angle-closure glaucoma (PACG). Methods: This single-centre prospective interventional case series enrolled 57 eyes from 53 PACG patients with medically uncontrolled intraocular pressure (IOP) and peripheral anterior synechiae of over 270°. Penetrating canaloplasty, mainly consisted of tensioning suture-aided Schlemm's canal dilation and a trabeculectomy, was performed to create a direct communication between the anterior chamber and the Schlemm's canal. Postoperative IOP, number of glaucoma medications and procedure-related complications were evaluated. Rate of success was defined as IOP ≤ 21, ≤18 and ≤15 mmHg, and a ≥30% IOP reduction without (complete) or with/without (qualified) IOP-lowering medications. Results: A total of 45 eyes had 360°catheterization successfully completed. The mean preoperative IOP was 33.9 AE 11.7 mmHg (range, 13-59.6 mmHg), on 3.2 AE 0.8 glaucoma medications (range 2-5), which was decreased to 15.4 AE 3.7 mmHg (range, 8.6-22.5) and 0.2 AE 0.6 (range, 0-3) medications at 6 months and 14.8 AE 3.5 mmHg (range, 9-24) and 0.1 AE 0.3 (range, 0-1) medications at 12 months postoperatively. Complete success at 12 months were achieved in 78.9% (95% CI: 0.65-0.93), 71.1% (0.56-0.86) and 50.0% (0.33-0.67) eyes at IOP ≤ 21, ≤18 and ≤15 mmHg, respectively. Transient IOP elevation (>30 mmHg, 26.7%) and hyphema (11.1%) were the most common early surgical complications. Conclusion: Penetrating canaloplasty in PACG appeared to have good efficacy and safety profiles in this pilot study. Further studies are justified.

Achieving Inner Aqueous Drain in Glaucoma Secondary to Iridocorneal Endothelial Syndrome: One Year Results of Penetrating Canaloplasty

“…Previously, we have successfully utilized the bleb-independent penetrating canaloplasty in primary angle closure glaucoma (PACG) with extensive PAS, providing evidence for the feasibility of IOP control through the physiological outflow pathway in eyes with angle closure. 19 In the present study, we further investigated the efficacy of this procedure in a prospective ICE case series. The design of intentionally placing the trabecular ostium and iridectomy at the location with the most extensive PAS boundary allows the internal filtration ostium to be in the posterior chamber and to be isolated from the anterior chamber.…”

“…Consistent with our previous observations in PACG, microhyphema (31.4%) and transient IOP elevations (22.9%) were the most frequent complications of penetrating canaloplasty. 19 Hyphema may be related to the blood reflux from the venous system, injury to the peripheral iris by the tensioning suture, bleeding during iridectomy, or ciliary processes injury. [28][29][30] In the current study, all cases with post-operative hyphema resolved within one week and seemed to have no adverse effect on the final success.…”

“…Transient IOP elevation commonly occurs after Schlemm's canal-related procedures, like canaloplasty and iStent, in primary open angle glaucoma (POAG), gonioscopy-assisted transluminal trabeculotomy (GATT) in childhood glaucoma, and penetrating canaloplasty in PACG. 19,29,[31][32][33][34] In addition to residual visco-agent, blood and inflammatory materials in Schlemm's canal can cause an early IOP spike. Failure of trabecular bypass procedures has been suggested to be due to atrophy of the collector channels secondary to persistent low aqueous outflow.…”

“…Detailed steps have been previously described (Supplemental video available at AJO.com). 19 In brief, a fornix-based conjunctival flap and a 4×3 mm limbus-based superficial scleral flap of 1/2 scleral thickness were made, followed by sculpting and removing of a 1.5×2mm deep scleral flap. The external wall of Schlemm's canal was carefully opened and unroofed.…”

“…If this is the case, a surgical procedure that can restore outflow from the anterior or posterior chamber to Schlemm's canal should be sufficient to control intraocular pressure (IOP) in eyes with extensive angle closure, while avoiding many drawbacks of trabeculectomy and valve implants. 19,20 In the previous study, we have demonstrated a bleb-independent penetrating canaloplasty as a successful surgical option for primary angle closure glaucoma. 20 In the present study, we report one-year efficacy of the procedure in a group of GS-ICE patients.…”