Influence of Gender on Occurrence of Chronic Subdural Hematoma; Is It an Effect of Cranial Asymmetry?

OBJECTIVE: Chronic subdural hematoma (CSDH) is a condition mostly present in older people. Men are more commonly affected than women. Several theories about male predominance could not enough to explain the reason for male predominance on CSDH. The purpose of this study is to find out whether there were any differences in the anatomy of cranium, which may contribute the pathogenesis or risk factors of CSDH. METHODS: The study population was consisted of 87 patients with CSDH and 100 patients with transient ischemic attack (TIA) from 2006 to 2013. We classified into four groups; group A (CSDH male 47), group B (CSDH female 40), group C (TIA male 50), and group D (TIA female 50). We measured the size of the cranium in the computed tomography scans, retrospectively. We define the difference of cranium (Dc), which is difference between the right and left radiuses. RESULTS: The Dc was significantly higher in patients with CSDH (group A and B)(p=0.03). The mean Dc was 3.49 mm in CSDH group (group A and B) and 2.14 mm in TIA group (group C and D). The mean Dc of CSDH group was significantly larger than that of TIA group (by t-test, p<0.01). CONCLUSION: Size and asymmetry of the cranium may be a risk factor of CSDH. Gender differences in the anatomy of cranium may contribute pathogenesis of CSDH.