Posters

Ab externo Schlemm’s canal surgery in management of open-angle glaucoma refractory to previous glaucoma surgeries

Poster Details

First Author: V.Kumar RUSSIA

Co Author(s):    M. Frolov   G. Dushina   E. Bozhok              

Abstract Details

Purpose:

To evaluate the effectiveness of segmental Schlemm’s canal (SC) distension using Kumar’s 2nd generation stainless steel spiral Schlemm’s canal expander (SCE) in decreasing intraocular pressure (IOP) in patients with open angle glaucoma (OAG) refractory to previous glaucoma surgeries.

Setting:

Ophthalmic unit of Skhodnya city hospital, Moscow province; People’s friendship university of Russia Medical Institute Department of Ophthalmology, Moscow, Russian Federation

Methods:

Results of Kumar’s 2nd generation SCE implantation into a segment of SC in 12 patients refractory to previous glaucoma surgeries were analyzed retrospectively. The 2.5-3.0 mm long SCE, made from 0.04mm thick medical grade stainless steel wire, having inner lumen diameter .12mm, outer - .2mm was implanted into SC ab externo after viscocanalostomy. SC was exposed without creating a window in Descemete’s membrane. Outcome measures: IOP change, number of glaucoma medications pre- and postoperatively and complications. Success rates were evaluated using World Glaucoma Association guidelines. A paired t-test was used for analysis. Results were significant when p less than .05.

Results:

Mean preoperative IOP was 25.3+/–4.8mmHg and mean number of medications - 2.5+/–.9. At 6 and 12 months mean IOP reduced by 44.6+/–21.5 and 36.6 +/–10.3% and was 12.5+/–3.7 (n=10; p=.0000026) and 15.3+/–2.9mmHg (n=9; p=.000012); use of medications reduced to 1.5+/–1.1(p=.032) and 1.8+/–1.3 (n=9; p=.176) and complete success was achieved in 20 (2/10) and 11.1% (1/9) cases, partial – in 70 (7/10) and 66.7% (6/9) cases respectively. Intraoperatively, microperforation of trabecular meshwork occurred in 1 case. Postoperatively, within 3 months after surgery 4 cases (33%) required YAG laser trabeculopuncture to control IOP.

Conclusions:

It is plausible that in some failed filter cases, there could be patent post-trabecular outflow and theoretically a distended SC with patent collector channel – aqueous vein system and transtrabecular passage may result in decrease in IOP in such cases. In this study a permanent segmental distension of the SC was achieved by inserting the SCE device in refractory glaucoma cases, which effectively decreased IOP. It can be hypothesized and concluded that in the presented technique viscocanalostomy created a direct communication between anterior chamber and SC, where as SCE kept the SC segment distended, which further enhanced the natural outflow.

Financial Disclosure:

NONE