Influence of cranial morphology on the location of chronic subdural haematoma.

BACKGROUND: The purpose of the present study was to evaluate the relationship between cranial morphology and location of a chronic subdural haematoma (CSDH) in patients with and without intracranial vault asymmetry.

METHOD: The study was conducted in 110 consecutive adult patients who underwent surgery for CSDH. The relationship between the following variables and CSDH was studied: sex, age, past medical history, history of trauma, interval between head injury and symptoms, clinical presentation, location of the CSDH, symmetry of the frontal and occipital intracranial vault on the CT scan and/or MR images, surgical treatment and outcome. Throughout the analysis, p < 0.05 was considered statistically significant.

FINDINGS: The frontal cranial vault was symmetrical in 48 patients (43.6%) and asymmetrical in 62 patients (56.4%). CSDH was more commonly bilateral in patients with a symmetrical frontal cranial vault than those with an asymmetrical shape (41.7% vs 17.7% and this difference is statistically significant (p = 0.01). In 62 patients with an asymmetric frontal skull vault, the CSDH was bilateral in 11 patients. In the remaining 51 patients, the CSDH was located on the same side of the most curved frontal convexity in 34 patients and on the side of the less curved frontal convexity in 17 patients. The occipital cranial vault was symmetrical in 44 patients (40%) and asymmetrical in 66 patients (60%). CSDH was more commonly bilateral in patients with a symmetrical occipital cranial vault than those with an asymmetrical one (40.9% vs 19.7%) and this difference was also statistically significant (p = 0.019). In 66 patients with an asymmetric occipital skull vault, the CSDH was bilateral in 13 patients. In the remaining 53 patients, the CSDH located on the same side of the most curved occipital convexity in 39 patients and on the side of the less curved occipital convexity in 14 patients.

CONCLUSIONS: Frontal and occipital intracranial vault morphology provides valuable information about location of CSDH. Bilateral CSDH is common in patients with symmetrical frontal and occipital cranial vault. In asymmetrical cranium, CSDH usually locates on the same side of the most curved frontal or occipital convexity. Identification of this relationship can be very useful to elucidate the origin and the pathogenesis of CSDH.