The Effect of Modified Chitosan Medical Membrane on the Inflammation and Recurrence After Primary Pterygium Excision: A Prospective Randomized Clinical Study

Abstract

Objective: To explore the role of intraoperative implantation modified chitosan medical membrane (MCMM) in postoperative inflammation and recurrence for primary pterygium excision with adjunctive amniotic membrane transplantation (AMT).

Design: Prospective, randomized, controlled, single-center clinical trial.

Methods: We included 54 patients (54 eyes) with primary pterygium scheduled for pterygium excision. They were randomly divided into two groups. The cryopreserved amniotic membrane (AM) group accepted pterygium excision with adjunctive AMT, and the MCMM group received AMT with adjunctive subconjunctival MCMM implantation during surgery. A follow-up of 3 years was conducted to observe pterygium recurrence. Primary outcomes included recurrence rate and tear cytokine levels after surgery. Secondarily, epidemiological data, visual acuity change, intraocular pressure (IOP), and ocular surface score were also collected. Data were analyzed using SPSS software version 26.0. The χ² test and Student t test were used to compare qualitative and continuous quantitative variables, respectively.

Results: A total of 54 subjects with 54 eyes were included, 26 in the AM group and 28 in the MCMM group. Corneal recurrence of pterygium occurred in 3 cases (11.5%), whereas 2 cases (7.7%) showed conjunctival recurrence in the AM group. Two cases (7.1%) experienced corneal recurrence, and 2 cases (7.1%) had conjunctival recurrence in MCMM group. Nonetheless, there was no significant difference in the recurrence rate of pterygium between the AM and the MCMM group (P = .903). In the 1-month and 3 to 6-month groups postoperatively, the MCMM group showed a significant reduction in the levels of interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) in the tear fluid compared to the AM group, respectively (IL-8: P = .003, TNF-α: P = .044, for 1 month; IL-8: P = .016 for 3 to 6 months, respectively), indicating that MCMM has a significant inhibitory effect on ocular surface inflammation after surgery. When comparing the patients with recurrent and non-recurrent conditions within each group after the surgery, both TNF-α and IL-8 showed an increase 1 month after the operation (AM group: TNF-α, P = .039, and IL-8, P = .001; MCMM group: TNF-α, P = .003, and IL-8, P = .047). There was no significant difference in age, IOP, visual acuity, and length of pterygium head between the two groups.

Conclusion: MCMM effectively reduced IL-8 and TNF-α tear levels and postoperative ocular surface inflammation, although it did not significantly influence the long-term recurrence rates compared to traditional AMT. MCMM could be a promising option for reducing postoperative inflammation of pterygium and for avoiding extensive dissection or antimetabolites.