Background: There are many factors that predispose an aneurysm to rupture, but there are few real, demonstrable causes that lead to rupture of the aneurysmal sac with a precise cause-effect mechanism.
Case description: We report a 74-year-old male patient with chronic subdural hematoma after head trauma, who underwent surgery for evacuation of the hematoma. During surgery, there was sudden copious loss of blood from the drainage tubes that were positioned subdurally. Immediate cerebral computed tomography scan and angiography revealed a subarachnoid hemorrhage at the level of the basal cisterns from a ruptured basilar apex aneurysm. We discuss the cause-effect relationship between the surgery with its positioning of subdural drains and the rupture of a previously unrecognized cerebral aneurysm.
Conclusions: The rupture of an unknown, previous "unruptured" aneurysm after craniotomy with subdural positioning of drainage, must be considered a possible complication.