Role of Methotrexate in Prevention of ERM in Pars Plana Vitrectomy

Abstract

Background: One of the most frequent complications after pars plana vitrectomy (PPV) is the development of the epiretinal membrane (ERM) which may cause visual distortion and poor visual outcomes. Its pathogenesis is mainly due to post-surgical inflammation and fibrocellular proliferation. Methotrexate has anti-inflammatory and antiproliferative effects that could decrease the formation of ERM.

Objective: To assess the effectiveness and side effects of intravitreal methotrexate injection as a prevention of the formation of epiretinal membranes after pars plana vitrectomy.

Study design: This study was prospective randomized controlled trial and conducted for 12 months.

Material and Methods: This prospective randomized controlled trial was conducted from September 2022 to August 2023. There were 100 patients with PPV divided equally into two groups. In Group A, IV injection of methotrexate (400 µg/0.1 mL) was injected intraoperatively, while in Group B, the PPV was performed in the normal manner.  Primary outcome was occurrence of ERM on optical coherence tomography (OCT). The data were analyzed by chi square and independent t-test with p < 0.05 as the significant value.

Results: ERM occurred in 8% of the methotrexate group compared to 30% in the control group (p = 0.003), with an odds ratio of 0.20 (95% CI: 0.06–0.66). The methotrexate group showed greater improvement in BCVA (0.45 ± 0.11 vs 0.31 ± 0.10 LogMAR, p < 0.001) and greater reduction in CMT (-128 ± 18 µm vs -94 ± 20 µm, p < 0.001). There was no significant difference between the groups with respect to the postoperative complications (p > 0.05).

Conclusion: Intravitreal methotrexate significantly decreases the formation of ERMs after PPV and improves functional and anatomical results without increasing the incidence of complications, making it a potential effective adjunctive therapy in vitreoretinal surgery.

Keywords: Epiretinal membrane, pars plana vitrectomy, methotrexate,  and vitreoretinal surgery.