Primary Needling of the Ab Interno Gelatin Microstent Reduces Postoperative Needling and Follow-up Requirements

Abstract

To evaluate the effect of primary needling at the time of ab interno gelatin microstent insertion on postoperative needling rates. Retrospective, interventional cohort study. Eighty-six eyes of 74 patients with no prior incisional surgery. Consecutive eyes with open-angle glaucoma refractory to medical treatment that underwent ab interno gelatin microstent insertion (XEN; Allergan Inc.) with or without primary needling. Primary outcome measure was the proportion of eyes requiring postoperative needling. Secondary outcome measures included the mean reduction in intraocular pressure (IOP), topical glaucoma medication use, complications, reoperations, and number of follow-up clinic visits over 12 months. Fifty-one eyes (42 patients, median age 74 years) underwent XEN surgery with primary needling at the time of surgery, and 35 eyes (32 patients, median age 73 years) underwent XEN surgery without routine primary needling. Eyes that received routine primary needling had an 84.8% lower rate of postoperative needling (3.9% vs. 25.7%, P= 0.003) and required fewer postoperative clinic visits (P= 0.043). Median IOP was 18.0 mmHg (interquartile range [IQR], 13.0-23.0) on 3.0 (IQR, 2.0-3.0) classes of topical medications at baseline. At 12 months, the median IOP was 11.0 mmHg (IQR, 9.0-14.0) in the primary needling group and 11 mmHg (IQR, 10.0-14.0) when primary needling was not routinely performed. Both groups demonstrated a high safety profile. In total, 5 eyes required further glaucoma surgery with insertion of a glaucoma drainage device. Primary needling at the time of XEN gel stent insertion is associated with a significant reduction in the need for postoperative needling and postoperative clinic visits. This modification provides a predictable postoperative course with a significant and sustained reduction in both IOP and glaucoma medication requirements with less intense postoperative management.