Supratentorial acute subdural haematoma during microvascular decompression surgery: report of three cases.

Supratentoiral haemorrhage during posterior fossa surgery is very rare. Authors report three cases of acute subdural haematoma occurred during microvascular decompression (MVD). Bleeding was observed in the suboccipital surgical area during operation but the origin of the bleeding was not confirmed intraoperatively in all cases. Decompression procedure was completed and immediate postoperative computed tomography revealed supratentorial subdural haematoma. This complication was observed during MVD in healthy young patients with hemifacial spasm in our cases. Flexion of the head with reduction of cerebrospinal fluid may have induced rotational movement of the cerebrum resulting in rupture of bridging veins, but no definitive mechanism that fulfils the clinical characteristics was clearly determined.