Complications of Surgery for Vertebrobasilar Artery Aneurysms and Final Comments

The International Cooperative Study on the Timing of Aneurysm Surgery evaluated the results of surgical and medical management in 3521 patients between December, 1980, and July, 1983. At admission, 75% of patients were in good neurological condition and surgery was performed in 83%. At the 6-month evaluation, 26% of the patients had died and 58% exhibited a complete recovery. Vasospasm and rebleeding were the leading causes of morbidity and mortality in addition to the initial bleed. Predictors for mortality included the patient's decreased level of consciousness and increased age, thickness of the subarachnoid hemorrhage clot on computerized tomography, elevated blood pressure, preexisting medical illnesses, and basilar aneurysms. The results presented here document the status of management in the 1980's.

A prospective, observational clinical trial was conducted by the International Cooperative Study on the Timing of Aneurysm Surgery to determine the best time in relation to the hemorrhage for surgical treatment of ruptured intracranial aneurysms. Sixty-eight centers contributed 3521 patients in a 2 1/2-year period beginning in December, 1980. Analysis by a prespecified "planned" surgery interval demonstrated that there was no difference in early (0 to 3 days after the bleed) or late surgery (11 to 14 days). Outcome was worse if surgery was performed in the 7 to 10-day post-bleed interval. Surgical results were better for patients operated on after 10 days. Patients alert on admission fared best; however, alert patients had a mortality rate of 10% to 12% when undergoing surgery prior to Day 11 compared with 3% to 5% when surgery was performed after Day 10. Patients drowsy on admission had a 21% to 25% mortality rate when operated on up to Day 11 and 7% to 10% with surgery thereafter. Overall, early surgery was neither more hazardous nor beneficial than delayed surgery. The postoperative risk following early surgery is equivalent to the risk of rebleeding and vasospasm in patients waiting for delayed surgery.

Deliberate occlusion of the basilar or vertebral arteries was performed in 201 patients with intracranial aneurysms, where the aneurysmal neck could not be clipped directly. The aneurysms arose from the basilar apex in 83 cases, the basilar trunk in 46, the vertebrobasilar junction in 35, and the vertebral artery in 37; 87% of the aneurysms were classified as giant lesions (> 2.5 cm). There were 85 upper basilar occlusions, 41 lower basilar occlusions, 29 bilateral vertebral occlusions, and 48 unilateral vertebral artery occlusions. The clinical follow-up period varied from 1 to 23 years, with a mean of 9.5 years. Overall long-term results were excellent in 68% of the patients, good in 5%, and poor in 3%; 24% died. Clinical outcome varied according to aneurysm site; excellent or good results were achieved in 64% of the patients with basilar apex, 76% with basilar trunk, 74% with vertebrobasilar junction, and 87% with vertebral artery aneurysms. Clinical outcome also varied depending on preoperative grade: 86% of the patients with an excellent presenting grade achieved excellent results. The size of the posterior communicating arteries was a good predictor of tolerance to basilar artery occlusion (p < 0.05). Successful aneurysm thrombosis was achieved in 78% of the patients. The neurological status in 26 patients (13%) deteriorated due to vertebrobasilar ischemia occurring within the 1st postoperative week, and thrombosis or embolism was implicated much more frequently than hemodynamic insufficiency. Subarachnoid hemorrhage (SAH) in 14 patients, vasospasm in five patients, and surgical trauma in seven patients accounted for additional morbidity in the 1st month following operation; however, many of these patients ultimately made an excellent recovery. Late vertebrobasilar ischemic complications or neurological deterioration from persistent mass effect occurred in 4% of patients with successful aneurysm thrombosis 6 weeks to 18 months after arterial ligation. Among the 43 patients with incompletely thrombosed aneurysms, 67% developed early or late neurological deterioration from SAH, progressive brain-stem compression, or brain-stem stroke, with 86% of the complications proving fatal.