The pathogenesis of delayed epidural hematoma after posterior fossa surgery.

The purpose of this study was to analyze the pathogenesis of delayed epidural hematoma (EDH) after posterior fossa surgery. Non-traumatic, non-arterial origin delayed EDH after posterior fossa surgery is extremely rare. Moreover, the pathogenesis of its supratentorial extension is obscure. Between April 1997 and June 2016, over 3300 patients underwent microvascular decompression (MVD) for neurovascular compression syndrome. The medical chart of four patients with delayed EDH were retrospectively reviewed. The median time from MVD to re-CT scan was 58 h (range, 33-100). All patients underwent hematoma evacuations. Intraoperative findings during hematoma evacuation revealed only an oozing hemorrhage from the transverse sinus with no definitive bleeding focus. The patients spent a median of 21.5 days (range, 11-39) at the hospital. At the last follow-up, all patients had fully recovered without significant neurological deficits and exhibited complete relief or minimal symptoms from hemifacial spasm (HFS). Postoperative uncontrolled bleeding from the dural venous sinus can sometimes cause an insidious-onset or delayed posterior fossa EDH.