Basal brain injury in aneurysm surgery

The goal of this study was to determine the frequency of lesions in the basal frontotemporal area that were related to surgical damage to the brain tissue. A prospective series of 101 patients with ruptured intracranial aneurysms were examined with high-field magnetic resonance imaging, 2 to 6 years (mean, 3.3 yr) after early surgery. Lesions in the basal frontotemporal region, on the side of the pterional approach, were observed for 36 patients. These lesions were not visible in computed tomographic scans obtained pre- or postoperatively or 3 months after subarachnoid hemorrhage. Patients with ruptured aneurysms in the anterior communicating artery exhibited fewer of these lesions than did patients with aneurysms in the internal carotid artery or middle cerebral artery; this difference was not statistically significant. The age of the patient, the duration and depth of hypotension, the amount of blood or ventricular enlargement in pre- and postoperative computed tomographic scans, and the incidence and severity of angiographic vasospasm in pre- and postoperative angiograms did not predict the existence of these lesions. The clinical conditions of the patients, as assessed using the Glasgow Outcome Scale, at 3 months after surgery and at the time of magnetic resonance imaging did not predict the existence of these lesions. Nine of the 10 patients who underwent surgical treatment of unruptured aneurysms on the contralateral side exhibited no signs of tissue damage. Surgical treatment of ruptured intracranial aneurysms seems to cause damage in the basal frontotemporal region in one-third of patients. The significance of these lesions remains unclear.