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Glaucoma Gel Implant Learning Curve in a Teaching Tertiary Hospital

Marques, Raquel Esteves, MD*,†; Ferreira, Nuno Pinto, MD*,†; Sousa, David Cordeiro, MD*,†,‡; Pinto, Joana, MD*,†; Barata, André, MD*,†; Sens, Paula, MD*,†; Abegão Pinto, Luís, MD, PhD*,†,‡

doi: 10.1097/IJG.0000000000001107
Original Study: PDF Only

Purpose: XEN® gel stent is a minimally invasive surgical device aimed at creating a subconjunctival drainage of aqueous humor, thereby reducing intraocular pressure (IOP). Being a novel device, doubts remain regarding the efficacy and safety of its implantation in the early stage of new users. This paper illustrates the XEN® implantation learning curve, assessed through several surgeons of different expertise.

Methods: Retrospective study on the first 6 XEN® implants performed by each of 10 certified ophthalmic surgeons. Simultaneous cataract surgery was allowed (phaco-XEN®). Primary outcomes: surgical time; intra- and postoperative surgical complications. Secondary outcomes: IOP; number of topical drugs in use; need for needling procedures. Outcome data were collected pre-operatively and at postoperative days 1, 7, 15, 30, 60 and 90. Statistical analysis was performed with STATA® 14.1 and SPSS®.

Results: Sixty patients were included (56.7% females). Mean age was 73 years [45-89]. Mean preoperative IOP was 23.8±8.95▒mmHg. From the included patients, 29 (48.3%) were submitted to simple XEN® implant, and 31 (51.7%) to phaco-XEN®. In both groups, mean surgical time decreased 9 minutes throughout the six-implant learning curve. Final IOP was 15±7.27▒mmHg in the stent group (−43% than baseline), and 14.92±3.32▒mmHg in the phaco-XEN group (−16% than baseline). In average, patients decreased two topical IOP-lowering drugs. Needling procedures were performed in 17 patients (28.3%).

Conclusions: XEN® gel stent was associated with fast learning curve, by both experienced surgeons and novice residents. By the sixth implant, both groups had considerably decreased mean surgical time and complication rates.

*Department of Ophthalmology, Hospital Santa Maria, Lisbon, Portugal

Ophthalmology Clinic, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal

Visual Sciences Study Center, CECV, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal

Raquel Esteves Marques and Nuno Pinto Ferreira: Co-first authors.

Sources of support and funding: No funding was received from the National Institutes of Health (NIH); Wellcome Trust; Howard Hughes Medical Institute (HHMI); or others.

Précis: XEN® gel stent was associated with fast learning curve, by experienced surgeons as well as novice residents. By the sixth implant, both groups had decreased mean surgical time and complication rates, independently of surgical expertise.

Disclosure: Funding/Support: no funding was received for the purpose of this work. Financial Disclosures: Luís Abegão Pinto received fees as lecturer for Allergan. No other financial disclosures. Other Acknowledgments: all stakeholders in the conduct of this study are listed as authors. No external contributions were received for the conduct of the study, statistical analysis, medical writing or counseling.

Disclosure: The authors declare no conflict of interest.

Reprints: Luís Abegão Pinto, MD, PhD, Hospital de Santa Maria – Departamento de Oftalmologia, Av. Prof. Egas Moniz, 1649-035 Lisboa, Portugal (e-mail:

Received July 18, 2018

Accepted September 22, 2018

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