Novel radiographic measurement algorithm demonstrating a link between obesity and lateral skull base attenuation

Area of Science:

• Neurosurgery
• Radiology
• Otolaryngology

Background:

• Spontaneous cerebrospinal fluid (CSF) otorrhea is often associated with attenuated tegmen plates, potentially linked to obesity and idiopathic intracranial hypertension (IIH).
• Previous research lacked objective data connecting obesity or IIH to skull base attenuation.

Purpose of the Study:

• To introduce a validated algorithm for measuring tegmen thickness using computed tomography (CT) scans.
• To compare tegmen thickness across three groups: patients with spontaneous CSF leaks, obese controls, and nonobese controls.

Main Methods:

• A retrospective review of patients from 2004 to the present.
• Selection of patients with spontaneous CSF otorrhea and matched obese (BMI >30 kg/m²) and nonobese (BMI <30 kg/m²) controls.
• Radiographic measurement of tegmen thickness with assessment of interrater validity.

Main Results:

• The study analyzed 98 patients: 37 in the CSF group (BMI 36.6), 30 obese controls (BMI 34.6), and 31 nonobese controls (BMI 24.2).
• The CSF group exhibited significantly thinner tegmen compared to both obese (P < .01) and nonobese (P = .0004) controls.
• Obese controls had thinner tegmen than nonobese controls (P < .00001), with a significant inverse correlation between skull base thickness and BMI. Signs/symptoms of IIH were most prevalent in the CSF group.

Conclusions:

• This study is the first to quantify lateral skull base thickness and correlate obesity with its attenuation.
• Obese patients with spontaneous CSF leaks demonstrate greater skull base attenuation than matched obese controls.
• These findings suggest an additional pathoetiological factor, potentially congenital, contributes to skull base dehiscence in these patients.