無症候性未破裂脳動脈瘤の治療成績・術後合併症

抄録

Many asymptomatic non-ruptured intracranial aneurysms are detected by non-invasive radiological examinations. On the other hand, the question has arisen whether surgical treatment of them is justifiable or not because their natural history is not clear. Therefore, we should discuss with patients the possible risk of surgical treatment when they decide to undergo surgery.
We retrospectively investigated treatment results and surgical complications involving asymptomatic non-ruptured intracranial aneurysms.
From Jan. 1998 to Dec. 1999, we treated 151 patients (56 male, 95 female) aged 22-77 (mean 58.4), with 201 non-ruptured asymptomatic intracranial saccular aneurysms, excluding multiple aneurysms combined with subarachnoidal hemorrhage, within 6 months of onset. Our policy was that surgical treatment was indicated if the aneurismal size was over 3-4 mm, the patient’s age was under 70, and their general condition was satisfactory. Neck clipping was the first choice of the surgical treatment. Direct surgery was difficult for such aneurysms as internal carotid artery aneurysm arising near the dural ring, those involving posterior circulation and those of a large-size. Such aneurysms were treated with intravascular embolization if possible. We evaluated the surgical risk by the number of the operations (169 cases).
Permanent morbidity resulted in 7 cases of the 112 direct surgery (6.3%) and 3 cases of the 56 cases of intravascular embolization (5.6%). No deaths resulted. The causes for the morbidity were brain damage or cranial nerve injury at the approach, a perforating artery injury or occlusion of the parent artery at the clipping in the direct surgery, and distal embolism and perforating artery occlusion in the intravascular embolization. The risk factor of the patients with postoperative neurological deficits was the aneurismal size (>10 mm, p<0.05) with no relation to the age over 70, preoperative ischemic complication of the brain, the triple major risk factors for arteriosclerosis (hypertension, diabetes mellitus, hyperlipidemia) or aneurysmal location. Transient or minor surgical complications were found in 58 cases (34.3%).
The prognosis of severe subarachnoidal hemorrhage caused by the rupture of the aneurysm is poor, and surgical therapy for non-ruptured aneurysm over 10 mm in size is difficult. We have, therefore, decided not to change our treatment policy. However, even for transient or minor complications, surgical risk is accompanied with the treatment of cerebral aneurysm. We should seek to reduce such surgical complications by analyzing their causes.