Transverse Sinus Stenosis in Lateral Skull Base Cerebrospinal Fluid Leaks and Idiopathic Intracranial Hypertension

Introduction: The association between transverse sinus stenosis (TSS) and both idiopathic intracranial hypertension (IIH) and anterior skull base spontaneous cerebrospinal fluid (sCSF) leaks has prompted questions regarding the potential treatment of both conditions with transverse sinus stenting, yet the relationship between TSS and lateral skull base sCSF leaks has been inadequately assessed. This study aimed to compare the rates of TSS in patients with lateral skull base sCSF leaks and patients with IIH without sCSF leaks.

Methods: A retrospective review of all adult patients with lateral skull base sCSF leaks and IIH without sCSF leaks was conducted at a tertiary care institution between January 2021 and December 2024. Included patients must have undergone magnetic resonance venography (MRV) and either met the Modified Dandy Criteria for IIH or undergone lateral skull base sCSF leak repair after the MRV. Outcome measures included demographics, clinical presentations, and rates of TSS. Descriptive and comparative statistics were conducted.

Results: The study included 18 sCSF leak and 78 IIH patients. Mean age was higher in the sCSF leak than the IIH group (67.9 ± 10 vs. 37.8 ± 10; p < 0.001), but there was no significant difference in mean BMI (36.3 ± 8.8 vs. 35.2 ± 8.6; p = 0.638). Fewer females were in the sCSF leak than in the IIH group (n = 8, 44% vs. n = 76, 97.4%; p < 0.001). The rate of individual TSS, including unilateral and bilateral cases, was higher in the IIH than in the sCSF leak group (n = 66, 84.6% vs. n = 7, 38.9%; p < 0.001). Bilateral stenosis was also more common in the IIH than in the sCSF leak group (n = 60, 76.9% vs. n = 4, 22.2%; p = 0.036).

Conclusions: Though a substantial number of patients with lateral skull base sCSF leaks have TSS, the significantly lower rate compared to that amongst patients with IIH suggests a difference in underlying pathogenesis or predisposition to clinical manifestations between the conditions. The prospect of transverse sinus stenting for the treatment of lateral skull base sCSF therefore remains in question.