Abstract
We report the natural history and surgical results of unruptured cerebral aneurysms (UCAs) of the posterior circulation. This study consists of 27 patients with 28 UCAs of the posterior circulation, 17 (18 UCAs) who did not undergo surgery and 10 (10 UCAs) who did. The data obtained were compared with that from 108 patients having 138 UCAs of the anterior circulation, including 39 patients (56 UCAs) who did not undergo surgery and 69 (82 UCAs) who did. In five of the 17 patients not undergoing surgery (29.4%), the aneurysms ruptured and the patients died. Patients with UCAs that showed mass signs or ischemic symptoms (Group 3) had a high probability of aneurysm rupture. The age distribution of patients having a rupture was 3 under 59 years, 2 between 60 and 69 years, and none over 70 years. The mean size of ruptured UCAs was 14.2mm in diameter (range: 5-30mm). UCAs of the posterior circulation had a higher risk of subsequent rupture than those of the anterior circulation: 29.4%vs. 15.4%. Although no operative mortality occurred, morbidity appeared in 4 patients (40%) including 2 transient (20%) and 2 permanent (20%) neurologic deficits. The two permanent deficits occurred in patients with giant aneurysms, one of whom was elderly. The morbidity rate was higher in patients undergoing surgical treatment of UCAs of the posterior circulation than those having surgery for aneurysms of the anterior circulation: 40%vs. 8.7%. If possible, UCAs of the posterior circulation should be treated surgically; however, the procedures should be chosen carefully, especially for elderly patients and those with large or giant aneurysms.
