Efficacy of Needling Revision After XEN Gel Stent Implantation: A Prospective Study.

INTRODUCTION: The XEN gel stent is currently the only minimally invasive glaucoma surgical device that targets the subconjunctival outflow pathway through an ab interno placement. It has demonstrated a significant intraocular pressure (IOP)-lowering potential and a favorable safety profile compared with traditional filtering surgery. However, despite a less invasive approach, the presence of a filtering bleb inevitably implies some risk of complications. The most commonly reported bleb-related complication, with rates as high as 45%, is bleb fibrosis associated with raised IOP. To restore filtration in those failing blebs, needling revision is considered the procedure of choice. In this study, we present the results of mitomycin C-augmented needling after XEN implantation. METHODS: This was a prospective, interventional study, conducted at a single tertiary glaucoma center. Fifty-one eyes of 51 patients with raised IOP associated with either a fibrotic or shallow bleb or increased vascularity following XEN gel stent implantation at the investigation site between January 2015 and June 2016 were enrolled in this study. Patients with other identified causes of filtration failure (stent malposition, internal ostium obstruction, retained viscoelastic) were excluded. Included patients who underwent mitomycin C-augmented needling revision, and follow-up examinations were conducted at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. The primary outcome was the magnitude of IOP reduction following needling revision at the last follow-up visit. Secondary outcome measures were the number of needling procedures carried out in all patients, the rate of patients requiring further filtering surgery following needling revision, and the rate of intraoperative and postoperative complications associated with needling revisions. RESULTS: The average age was 74.4±9.6 years; 66.7% (n=34) were female individuals. Primary open-angle glaucoma was the most common diagnosis (n=21, 41.2%). A total of 78 needling procedures were performed over the 24-month follow-up. Overall 20 of 51 eyes (39.2%) required >1 needling revision, and 14 eyes (24.5%) eventually required reoperation to maintain IOP within their desired target range. Before XEN implantation, mean preoperative IOP was 22.3±8.2 mm Hg and decreased to 14.1±8.0 mm Hg at day 1 postoperatively (-36.8%). The last measured IOP before the first needling revision was on average 23.6±8.9 mm Hg, which reduced to a mean 12.1±4.2 mm Hg at the first postrevision appointment (-48.7%). At the last follow-up appointment, on average 17.0±7.0 months after the first needling, the mean IOP was 14.3±4.1 mm Hg (-35.9% and -39.4% from preoperative and prerevision baselines, respectively). Complications associated with needling revisions were partial amputation of the XEN implant during needling (n=2, 3.9%), hypotony with choroidal detachment (n=1, 2%), and failure to achieve target IOP requiring subsequent surgery (n=14, 27.5%). No association was found between any of the recorded characteristics and the number of needling revisions performed or their outcomes. DISCUSSION: The present study shows that needling revision following XEN gel stent implantation is a relatively safe and efficient intervention to restore filtration in failing blebs, with a significant and durable IOP-reduction potential.

Results of CO2 Laser-assisted Deep Sclerectomy as Compared With Conventional Deep Sclerectomy.

PURPOSE: To evaluate the efficacy of CO2 laser-assisted sclerectomy surgery (CLASS) compared with classic nonpenetrating deep sclerectomy (NPDS) with implant in medically uncontrolled glaucoma patients. MATERIALS AND METHODS: Patients who underwent primary filtration surgery with CO2 laser system at the time interval between July 2010 and April 2011 were identified, their medical files were reviewed, and their results were compared with matched control group who underwent classic NPDS with intrascleral implant at the same time period. Intraocular pressure (IOP) was measured at baseline, 1 week, and 3, 6, 12, 18, and 24 months, respectively. Main outcome measures were: IOP, use of supplemental medical therapy, and failure (5 mm Hg>IOP>18 mm Hg, reoperation for glaucoma, or loss of light perception). RESULTS: A total of 58 patients were reviewed, including 27 in the CLASS group and 31 in the NPDS group. For the CLASS group the follow-up (mean±SD) was 20.7±6.8 months, the mean preoperative IOP was 23.3±8.2 mm Hg (range, 10 to 38 mm Hg), and the mean number of antiglaucoma medication before surgery was 3.0±1.0 (range, 1 to 4). At final follow-up visits, the mean IOP was 11.7±3.1 mm Hg (range, 6 to 19 mm Hg), and the mean number of antiglaucoma medication was reduced to 1.0±1.6 (P<0.0003). The complete success rate (IOP≤18 mm Hg without antiglaucoma medication) was 73% and the qualified success rate (IOP≤18 mm Hg with/without antiglaucoma medication) was 96%. For the control group the mean follow-up was 17.6±6.7 months, the mean preoperative IOP was 23.1±7.3 mm Hg (range, 14 to 44 mm Hg), and the mean number of antiglaucoma medication before surgery was 3.0±0.8 (range, 1 to 4). At final follow-up visits, the IOP was 13.3±3.6 mm Hg (range, 8 to 20 mm Hg), and the mean number of antiglaucoma medication was reduced to 0.7±1.1 (P<0.0004). The complete success rate and the qualified success rate were 71% and 89%, respectively. CONCLUSIONS: A new technique using a CO2-laser ablation system allows precise and easy creation of the scleral space and ablation of Schlemm canal. This technique has been shown to be as efficient as the standard NPDS surgery in terms of IOP-lowering effect. This would render the deep sclerectomy an easier glaucoma surgery.