Microsurgical treatment strategy for large and giant aneurysms of the internal carotid artery

Objective: We aimed to summarize our microsurgical treatment results for large (10-25 mm) and giant (>= 25 mm) intradural internal carotid artery (ICA) aneurysms over a 7-year period at a single institution and to describe our detailed strategy. Patients and methods: We reviewed the records of 68 patients with 69 aneurysms, including large and giant intradural ICA aneurysms, treated using microsurgical techniques from January 2008 to December 2014. We used adenosine-induced cardiac standstill or retrograde suction decompression for some aneurysm clipping cases and performed bypass surgery if needed. Results: Fifty-eight large and giant ICA aneurysms (84%) were treated with direct clipping, including 6 aneurysms (9%) clipped using adenosine-induced cardiac standstill and 10 aneurysms (14%) clipped using suction decompression. Eleven unclippable aneurysms (16%) were trapped with extracranial-intracranial bypass. Good or excellent results (modified Rankin Scale scores 0-2) were obtained in 47 patients with unruptured aneurysms (92%) and in 14 patients with ruptured aneurysms (82%) at the 6-month follow-up. Of 17 patients with visual disturbances before treatment, 11 (65%) had improved vision after surgical treatment. A remnant sac was found in 20 cases (29%) on digital subtraction angiography performed immediately postoperatively. At the median follow-up of 22 months, we encountered 3 recurrent aneurysm cases (5%) among the 58 aneurysms that were followed up. Conclusion: Our study demonstrated that microsurgical treatment of large and giant intradural ICA aneurysms remains competitive to flow-diverting treatment, if the surgeon is prepared to perform multifarious surgical methods, including adenosine administration, retrograde suction decompression, and bypass vascular anastomosis.