Bypass Surgery for Complex Internal Carotid Artery Aneurysms: 39 Consecutive Patients

Objective Bypass surgery is a special technique used to treat complex internal carotid artery (ICA) aneurysms. The aim of this retrospective study is to provide a comprehensive description of treatment and outcome of complex ICA aneurysms at different ICA segments (cavernous, supraclinoid, ICA bifurcation) treated with bypass procedures. Methods We identified 39 consecutive patients with 41 complex ICA aneurysms that were treated with 44 bypass procedures between 1998 and 2016. We divided the aneurysms into 3 anatomic subgroups to review our treatment strategy. All the imaging studies and medical records were reviewed for relevant information. Results The aneurysm occlusion ( n  = 34, 83%) or flow modification ( n  = 5, 12%) was achieved in 39 aneurysms (95%). The long-term bypass patency rate was 68% ( n  = 30). Minor postoperative ischemia or hemorrhage was commonly seen ( n  = 20, 51%), but large-scale strokes were rare ( n  = 1, 3%). Preoperative dysfunction of extraocular muscles (cranial nerves III, IV, and VI) showed low-to-moderate improvement rates (20%–50%). Preoperative vision disturbance (cranial nerve II) improved seldom (22%). At the latest follow-up (mean; 51 months) 29 patients (74%) were independent (modified Rankin Scale ≤2). Conclusions Bypass surgery for complex ICA aneurysms is a feasible treatment method with an acceptable risk profile. Patients should be informed of the uncertainty related to improvement of pretreatment cranial nerve dysfunctions.