[Prophylactic external decompression for massive cerebral infarction].

When cerebral infarct extends over a wide area and severe cerebral edema follows, there may be some cases where external decompression is necessarily indicated. Decompression is generally performed when signs of tentorial herniation appear and brainstem damage seems to be still reversible. We have been performing operations in such indication, but result of operations were poor. We were led to search for a accurate way to save acute massive cerebral infarction. A prophylactic external decompression being carried out just when a tentorial herniation is certainly imminent, could be an option. Analysis of serial CT scannings on infarction cases definitely revealed that before cerebral edema became manifest and tentorial herniation developed, there was a period when there were such findings as uniform: low density appears over the whole middle cerebral artery territory. this low density is homogeneous. lateral ventricle is slightly compressed and cortical sulci disappear suggesting slight cerebral edema. We have tried external decompression on three cases as soon as we found these CT findings, before there were signs of tentorial herniation and the outcome were satisfactory.