[Indications for external ventricular drainage after clipping of ruptured aneurysms in the acute stage].

The indication for external ventricular drainage after clipping of ruptured aneurysms in the acute stage is evaluated. Since 1990, 234 patients who presented with subarachnoid hemorrhage (SAH) and underwent aneurysmal clipping in the acute stage were evaluated retrospectively. Patients with ventricular dilatation had intraoperative placement of a ventriculostomy to obtain intraoperative brain relaxation, but the ventricular catheter was removed at the end of the surgery. All these patients were managed postoperatively in a similar fashion with no ventricular drainage, avoidance of dehydration complemented by a course of sodium ozagrel and nicardipine or fasudil hydrochloride. Acute hydrocephalus was defined as clinically and radiographically demonstrated ventricular dilatation that developed within 2 weeks of the onset of SAH and that required ventricular drainage. Three surgical approaches were employed; pterional approach (PA) for the aneurysms of the anterior circulation and upper basilar artery in 207 patients, interhemispheric approach (IHA) for the aneurysms of the pericallosal artery in 11 patients and lateral suboccipital approach (LSA) for the aneurysms of the vertebral arteries in 16 patients. No significant differences were found among these three approach groups in Fisher CT classification and the Hunt & Kosnik gradings. Four patients developed acute hydrocephalus within two weeks of surgery: three patients were operated on via LSA and one through IHA. Compared to the IHA or LSA, PA was superior for reestablishing cerebrospinal fluid circulation, because it is possible to remove more subarachnoid clot in the basal cisterns than to do so in the other two approaches. Opening of the lamina terminalis and the Liliequist membrane are also possible using PA. In conclusion, PA can prevent development of acute hydrocephalus, whereas postoperative ventricular drainage may be necessary in patients operated upon via IHA or LSA.