Surgical Flow Alteration for the Treatment of Intracranial Aneurysms That Are Unclippable, Untrappable, and Uncoilable

OBJECTIVE: The treatment of complex intracranial aneurysms remains challenging. One approach is the application of surgical flow alteration to treat aneurysms that are neither clippable, trappable, or coilable. The efficacy and limitations of surgical flow alteration have not yet been established. METHODS: Cases of complex aneurysms treated with surgical flow alteration (proximal occlusion with or without bypass, distal occlusion with or without bypass and bypass only) were included in this retrospective study. RESULTS: Among a total of 16 cases, there were 7 giant aneurysms (≥25 mm diameter) and 9 large aneurysms (>10 mm diameter); 15 of 16 aneurysms were unruptured. There were 8 aneurysms located in the anterior circulation, while the other 8 were in the posterior circulation. Aneurysms were treated with proximal occlusion in 10 cases and distal occlusion in 5 cases; in 1 case, the aneurysm occluded spontaneously after bypass without parent artery occlusion. All but 2 cases underwent prior or concurrent bypass surgery. Complete obliteration of the aneurysm at the latest imaging follow-up was shown in 12 of 16 cases (75.0%). Bypass patency was confirmed in 13 of 15 cases (86.7%). Surgery-related morbidity developed in 3 cases (18.8%, Glasgow outcome scale of 4) and all were perforator infarctions. There were no mortalities. CONCLUSION: Surgical flow alteration resulted in a high rate of aneurysmal obliteration with acceptable morbidity. Although several limitations remained, it could represent an alternative method for treating complex aneurysms.