The Effects of Age and Race on Calvarium, Tegmen, and Zygoma Thickness

OBJECTIVE Temporal bone spontaneous cerebrospinal fluid (sCSF) leaks are characterized by defects in the tegmen along with calvarial thinning without associated thinning of the extracranial zygoma. The authors sought to determine the effect of age and race on calvarial, tegmen, and zygoma thickness. STUDY DESIGN Retrospective cohort study. SETTING Tertiary Referral Center. PATIENTS A total of 446 patients with high-resolution head computer tomography (CT) imaging from 2003 to 2018. INTERVENTION(S) Calvarial, tegmen, and zygoma thicknesses were measured using 3D slicer. MAIN OUTCOME MEASURE(S) Effects of age and race on calvarium, tegmen, zygoma thickness. RESULTS Among all patients, increased age was associated with increased thickness of the calvarium [95% CI, 0.0002 to 0.007 mm/year, P < 0.05] and tegmen [95% CI, 0.00039 to 0.0075 mm/year, P = 0.03], but decreased thickness of the zygoma [95% CI, -0.013 to -0.005 mm/year, P < 0.001]. When compared to white patients, black patients had thicker mean [SD] calvaria (2.63 [0.61] versus 3.30 [0.79] mm; difference, 0.67 mm; [95% CI, 0.57 to 0.77]; Cohen d, 1.02), tegmen (0.73 [0.34] versus 0.92 [0.36] mm; difference 0.19 mm; [95% CI, 0.101 to 0.279]; Cohen d, 0.533) and zygoma (4.89 [0.81] versus 5.55 [0.91] mm; difference, 0.66 mm; [95% CI, 0.53 to 0.79]; Cohen d, 0.78). CONCLUSIONS Racial differences exist in calvarial and zygoma thickness. Aging generally leads to increased calvarium and tegmen thickness, suggesting that early onset of obesity and comorbid conditions known to thin the skull base may predispose patients to developing sCSF leaks by reversing the effects of age.