[Risks of surgical treatment for unruptured intracranial aneurysms].

The risks of surgical treatment for unruptured intracranial aneurysms, as well as the significance of evaluating cerebral blood flow (CBF), are here reported. Out of 72 patients who underwent unruptured aneurysm surgery without such complications as occlusion of the main trunk or perforating arteries, or brain contusion, and who according to CT scans, did not have new lesions related to the operations, 18 patients (25%) developed neurological deficits postoperatively. In 17 of these 18 patients, postoperative neurological deficits (frontal sign: 7, paresis: 4, and seizure: 6 cases) disappeared within 2 weeks following the operations. In the other patient, who was treated for subcortical hematoma in the left temporal lobe before aneurysm surgery, permanent speech disturbance appeared postoperatively. In the 18 patients with postoperative neurological deficits, the mean CBF value (36.2ml/100g/min) was statistically lower than that in the patients (46.2ml/100g/min) who had no postoperative neurological deficits (p less than 0.001). The rate of the patients with lower CBF values who developed postoperative neurological deficits, was statistically higher than that of patients with CBF values greater than 40ml/100g/min (p less than 0.002). In the patients with lower CBF values, common operative procedures for unruptured aneurysms such as craniotomy and mild brain retractions, may damage brain tissue. Careful perioperative management is needed for patients who undergo unruptured aneurysm surgery, because a lower CBF value may represent the degree of brain fragility.