Delayed acute subdural hematoma treated with endoscopic procedure: A case report.

Background: Delayed acute subdural hematoma (DASDH) is defined as late onset ASDH with the absence of any abnormal radiological and clinical findings at initial examination. Moreover, this entity is very rare in traumatic brain injury and its mechanism is still unclear. Recently, endoscopic surgery for ASDH has also been performed. In this case, we describe some considerations of the mechanism of DASDH and review previous literature and usefulness of endoscopic surgical procedure for ASDH. Case Description: A 73-year-old man fell at night, and visited a former medical institution by himself. No abnormal neurological finding was detected. Head computed tomography (CT) detected no abnormal finding. He was diagnosed minor head injury and was hospitalized at midnight and discharged after brain magnetic resonance image (MRI) next day. Brain MRI also detected no abnormal findings. Three days later, he visited our hospital himself, because of the severe headache. Neurologically, he had a mild consciousness disturbance and head CT revealed left ASDH. We performed endoscopic evacuation of hematoma under local anesthesia. Then, the clot was evacuated under the endoscopic procedure through dilated burr hole and pulsatile bleeding from the cortical artery was observed, which was considered to be the source of the ASDH. The patient's consciousness disturbance was improved immediately after surgery and he discharged without neurological deficit. Conclusion: We revealed the source of bleeding of DASDH under endoscopic procedure and described hypothesis and speculation of its cause in our case. DASDH is rare entity, so we need further experiences and more considerations.