Utility of Intrathecal Fluorescein in Transmastoid Repair of Temporal Encephaloceles

Objectives: To assess the safety and efficacy of intrathecal fluorescein administration during transmastoid repair of temporal lobe encephaloceles and identify predictors for intraoperative fluorescein identification. Methods: This was a retrospective case-control study of consecutive adult patients with temporal lobe encephaloceles repaired via transmastoid approach from October 2012 to October 2024 at a single tertiary academic medical center. Medical records of qualifying patients were searched for demographics, diagnostic workup, disease characteristics, and intraoperative and postoperative outcomes. Analysis incorporated the Wilcoxon rank-sum, Pearson’s X 2 , and Fisher’s exact tests, along with unadjusted Kaplan-Meier estimates. Outcomes included encephalocele recurrence and symptomatic resolution rates, fluorescein complications, and rates and predictors of intraoperative fluorescein identification. Results: 38 patients met inclusion criteria (age 59.8 + 11.9 years, BMI 35.8 + 8.7 kg/m 2 , 23 [60.5%] female). Recurrence (0% vs 11.5%, P = .54) and symptom resolution (83.3% vs 88.5%, P = .64) rates did not differ between patients who received and did not receive intrathecal fluorescein. No fluorescein-related complications were reported. Fluorescein was intraoperatively detected in six-twelfths cases, yielding a sensitivity of 50%. No demographic or clinical variables, including higher BMI, history of prior encephalocele, and size of largest defect, were associated with intraoperative fluorescein identification. Conclusions: Intrathecal fluorescein administration preliminarily appears to be a safe adjunctive tool to identify the leak source in the transmastoid repair of temporal lobe encephaloceles, but its risk-benefit ratio remains up for debate. Higher-powered studies are necessary to explore its utility in specific circumstances and to determine which patients may benefit most.