(1271) The Role of Endonasal Eustachian Tube Obliteration in Lateral Skull Base Cerebrospinal Leak Repair

Introduction: Few studies have examined the efficacy of eustachian tube obliteration (ETO). Endonasal ETO approach is increasingly used when prior lateral cerebrospinal (CSF) repair fails and CSF drains from the eustachian tube. This study describes a cohort of ETO patients and evaluates factors associated with ETO repair failure.

Methods: Retrospective cohort study of patients who had undergone ETO for CSF leak from 1/2010-7/2025 seen by rhinology at a tertiary academic center. We defined no-leak and recurrent-leak cohorts and evaluated the odds of sex, tumor type, BMI, vascularized flap repair, and infection between cohorts using Fisher’s tests and Welch t-tests.

Results: The study cohort consisted of 19 subjects. Cohort mean age is 50 years (SD=14), 53% female, 79% White, 11% Black, 32% Hispanic/Latino. Tumor: 63% vestibular schwannoma, 26% meningioma, and 11% other tumors. Lateral approach: 37% trans-labyrinthine, 37% rectosigmoid, 16% middle cranial fossa, and 11% other/combined approaches. Seven subjects (37%) had recurrent post-ETO leaks.

A higher proportion of females had recurrent-leaks (OR=3.5). Pre-op BMI was similar between cohorts (p=0.46) and for BMI 1 year post-op. We found no differences between cohorts in lateral surgical approach (p=1), tumor type (p=0.80), lumbar drain use (p=0.65), or ETO with/without a pedicled blood supply (p=0.81). Pre-ETO infection (OR=7.2, p=0.12) and post-ETO infection (OR=11.4, p=0.15) were more likely in recurrent leaks. Mean follow-up of recurrent-leak cohort was 66 weeks vs. 32 weeks no leak. Study limitations include the small, unpowered sample size and the bias of following recurrent-leak subjects for longer.

Conclusions: Flap type, tumor, or surgical approach do not appear to be associated with ETO failure. Pre-operative and post-operative infection appear to have a clinically significant association with ETO failure.