[Effect of external decompression on the development of delayed ischemic neurological deficits after subarachnoid hemorrhage].

The protective effect of a large decompressive craniectomy against delayed ischemic neurological deficits (DIND) was evaluated in patients operated on after subarachnoid hemorrhage due to a ruptured aneurysm. In 54 cases, a large decompressive craniectomy was performed (Group D), and 41 patients underwent conventional craniotomy (Group ND). Transient DIND appeared in three (17%) of the 18 Group D patients of Hunt and Kosnik grade I or II, but permanent deficits were not observed in this group. In Group ND, permanent DIND developed in seven (21%) of the 33 grade I or II patients, despite their having received the same medical care. This difference was statistically significant. However, there were no differences in outcome among patients of grades III, IV, and V. These results suggest that, at least in patients of grade I or II, a large decompressive craniectomy, performed early, will prevent DIND after subarachnoid hemorrhage. The procedure may prevent the increase in intracranial pressure and decrease in perfusion pressure brought on by vasospasm and the development of brain edema.