• Glaucoma

    Review of: Primary needling of the ab interno gelatin microstent reduces postoperative needling and follow-up requirements

    Kerr N, Lim S, Simos M Ophthalmology Glaucoma, November-December 2021

    This retrospective interventional cohort study evaluated the effect of primary needling at the time of insertion of the XEN microstent on postoperative needling rates.

    Study design

    A total of 86 consecutive eyes with open-angle glaucoma refractory to medical treatment that underwent ab interno gelatin microstent insertion (XEN Gel Stent; Allergan Inc.) with or without primary needling were evaluated during the course of 12 months.


    The primary outcome measure was the proportion of eyes requiring postoperative needling. Secondary outcome measures included the mean reduction in IOP, topical glaucoma medication use, complications, reoperations, and number of follow-up clinic visits during 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 surgery without routine primary needling. Eyes that received routine primary needling had an 85% lower rate of postoperative needling (4% vs. 26%) and required fewer postoperative clinic visits.


    This study has all the limitations of a retrospective study. In addition, the long-term implications of the study are limited due to the short follow-up duration. Presumably, this study would have detected early fibrosis. Last, XEN placement as well as postoperative needling are often accompanied by injection of antifibrotic agents. It would have been useful to know which agents and what concentration/doses were used at the various stages of the intervention (intraoperative placement vs postoperative needling).

    Clinical significance

    Primary needling at the time of XEN microstent insertion is associated with a significant reduction in the need for postoperative needling and postoperative clinic visits, as well as a predictable and easier postoperative course with significant and sustained reduction in both IOP and glaucoma medication requirements.