Overdrainage after endoscopic third ventriculostomy: an unusual case of chronic subdural hematoma--case report and review of the literature.

Endoscopic third ventriculostomy is considered a safe technique for the treatment of obstructive hydrocephalus. However, the literature contains several reports of complications related to this procedure. We describe a case of chronic subdural hematoma (CSDH) after ETV, which required surgical evacuation, in a 69-year-old male patient completely asymptomatic up to the control MRI four weeks after the operation. We believe this unusual complication could result from the ICP changes caused by ETV. In our opinion, successful ETV gives a boost to CSF absorption, and overdrainage may evolve also in endoscopic treatment of obstructive hydrocephalus. This situation could be the starting point of the subdural collection. We review the literature and discuss the causes that may lead to CSDH after ETV procedure.