Posterior-fossa haemorrhage after supratentorial surgery--report of three cases and review of the literature.

We present clinical details of three patients with posterior fossa haemorrhage after supratentorial surgery and discuss possible pathomechanisms of this rare complication. All patients were males of advanced age. Two patients presented with a history of hypertension. In all patients the occurrence of haemorrhage was associated with loss/removal of large amounts of cerebrospinal fluid (CSF) either intra-operatively (one patient undergoing aneurysm surgery) or postoperatively (all three patients: drainage of subdural hygromas or chronic subdural haematomas in two, external ventricular drainage in one patient). Treatment consisted in haematoma evacuation and/or external ventricular drainage. Two patients died, one patient recovered completely. Although haematomas distant from a craniotomy site are a well known entity, a review of the literature identified only 25 published cases of posterior fossa haemorrhage after supratentorial procedures in the CT era. Most often disturbances of coagulation, positioning of the patient and episodes of hypertension have been associated with this complication. Only one author described the occurrence of a haemorrhage after drainage of a supratentorial hygroma. We suggest that the loss of large amounts of CSF intra-operatively and post-operatively may lead to parenchymal shifts or a critical increase of transmural venous pressure with subsequent vascular disruption and haemorrhage.