Subdural hygroma due to traumatic rupture of a middle cranial fossa arachnoid cyst that has transformed into a chronic subdural hematoma after burr hole operation: A case report

The increase in CSDH may have disrupted the flap-valve mechanism of the arachnoid cyst and subdural collection. When performing a burr hole operation for a subdural hygroma caused by the rupture of an arachnoid cyst, placement of a subdural drain may be desirable, and consideration of the possibility of CSDH is necessary.