Objective: To determine the frequency of unexpected major arterial occlusion and incomplete aneurysm clipping on intraoperative angiography after cerebral aneurysm clipping and to determine factors that predict these unexpected findings.
Methods: Data was collected prospectively on 100 consecutive craniotomies for the clipping of 107 aneurysms in 92 patients. Patient age and sex, aneurysm location and size, how the aneurysm presented, day of surgery after hemorrhage, intraoperative rupture, and postoperative course were recorded. After clipping, the surgeon recorded whether he thought the aneurysm was obliterated and whether he thought the clip occluded a major artery. Intraoperative angiography was then performed. The incidence of unexpectedly finding a major arterial occlusion or residual aneurysm was determined. Factors predicting these unexpected findings revealed by intraoperative angiography were identified by logistic regression.
Results: There were 11 giant (10%), 13 posterior circulation (12%), and 68 (64%) ruptured aneurysms. Unexpected angiographic findings necessitating at least one clip adjustment occurred in 12 cases (11%). Clip readjustments restored flow through six major arterial occlusions (6%) and completely obliterated 10 persistently filling aneurysms (10%). Logistic regression showed that factors predicting an unexpected arterial occlusion were giant aneurysm and basilar apex location (P < 0.05). Unexpected residual aneurysm was predicted by giant aneurysm and posterior communicating artery location (P < 0.05).
Conclusion: Intraoperative angiography detects unexpected arterial occlusions and residual aneurysms in 12% of cases and can decrease complications of aneurysm surgery, although the yield in unselected patients is low. The subgroup of patients with giant, basilar apex, and posterior communicating artery aneurysms has a significantly higher incidence of untoward findings and may benefit from increased usage of intraoperative angiography.