Objective: Recent reports in the literature have described a significant discrepancy in adverse outcomes between coil embolization (CE; 10%) and surgical clipping (SC; 25%) for the management of unruptured intracranial aneurysms (UIA). This discrepancy led us to analyze our experience.
Methods: In 1996, we designed a prospective study of patients with UIA in which CE was considered the treatment of choice and was performed if the interventional neuroradiologists deemed the aneurysm's fundus-to-neck ratio accessible for CE. SC was performed only if complete CE was unlikely to be achieved or in patients in whom CE already had failed.
Results: CE was performed in 38 patients with at least one UIA (41 UIAs, 83% in the anterior circulation). SC was performed in 39 patients with at least one UIA unsuitable for CE (59 UIAs, including 6 after failed CE, 96.5% in the anterior circulation). For CE, the total obliteration rate was 56.1%, the subtotal was 14.6%, and CE failed in 29.3%. There were transient complications in 10% of the cases and permanent complications in 7.5%. Of the 12 failed CE procedures, 7 (58%) were performed for middle cerebral artery aneurysms. For SC, the total obliteration rate was 93.2%, the subtotal was 1.7%, and SC failed (wrapping) in 5.1%. There were transient complications in 16.3% of the patients and permanent complications in 1.7%. The success rate for CE was similar to that for SC only when CE was used for aneurysms with a fundus-to-neck ratio of at least 2.5.
Conclusion: SC can produce better results than CE in patients with UIA of the anterior circulation. CE as a first-line treatment should be reserved for patients with UIAs with a fundus-to-neck ratio of 2.5 or greater.