Body Mass Index and Olfactory Fossa Depth in Patients with and without Spontaneous Cerebrospinal Fluid Leaks

Background/Aims: Spontaneous cerebrospinal fluid (SCSF) leaks are associated with a high body mass index (BMI) and an expanded skull base. The purpose of this study is to determine if a correlation exists between BMI and olfactory fossa depth (OFD) in patients with SCSF leaks and those without. Methods: This is a cross-sectional study evaluating the correlation between OFD and BMI in patients with and without SCSF leaks. OFD was measured on computed tomography obtained in temporal proximity to the BMI. Results: Patients with SCSF leaks had a deeper mean OFD than controls (6.39 vs. 5.46 mm, p = 0.013) and a larger BMI (38.2 vs. 30.5, p = 0.0003). Pearson correlation was positive between BMI and OFD in women from the control group (R = 0.319, n = 93, p = 0.002 on the left; R = 0.313, n = 93, p = 0.002 on the right) but insignificant in men. Conclusions: The olfactory fossa is deeper and the BMI higher in patients with SCSF leaks than in those without. Differences were statistically significant. Higher BMI may predict deeper olfactory fossa in women but not in men. These findings suggest expansion of weak points in the skull base as precursors to the development of SCSF leaks in response to elevated CSF pressures, particularly in women.