Balloon-assist technique for endovascular coil embolization of geometrically difficult intracranial aneurysms

The balloon-assist or neck-remodeling technique is an adjunctive method devised for the endovascular coil embolization of aneurysms characterized by a wide neck or unfavorable geometric features. Since its initial description, there have been few data to corroborate its utility, efficacy, and safety in aneurysm embolization.

Twenty patients (19 female patients and 1 male patient) with 22 aneurysms (19 unruptured aneurysms and 3 ruptured aneurysms) underwent balloon-assisted coil embolization. The balloon-assist technique was performed in the same treatment session after conventional coil embolization had failed in 55% of cases (12 of 22 cases) and was the primary treatment in 45% of cases. The majority of aneurysms were located in the supraclinoid carotid artery (13 paraophthalmic and 3 superior hypophyseal aneurysms). The mean angiographic measurements included a fundus of 8.7 +/- 3.7 mm, a neck of 5.3 +/- 2.2 mm, and a comparatively unfavorable fundus/neck ratio of 1.33 +/- 0.23.

Technical success was achieved in 77% of cases (17 of 22). The rate of aneurysm obliteration at the end of the procedures was 97 +/- 3.8%. Angiographic follow-up data (mean follow-up period, 10.3 mo) obtained for 89% of the treated aneurysms (15 of 17) confirmed stable mean occlusion of 97.8 +/- 3.8%. Technical complications included two cases of asymptomatic distal vessel thromboembolism, which resolved angiographically within 24 hours, and one case of intraprocedural rupture of an arteriovenous malformation-related feeder artery aneurysm, which resulted in no neurological deficits and required no further treatment (transient complication rate, 13.6%; 3 of 22 cases). There were no deaths and no procedure-related 30-day or permanent morbidity.

The balloon-assist method of coil embolization is characterized by promising intermediate-term angiographic and clinical outcomes and acceptable morbidity and mortality rates. Although this adjunctive method requires the use of an additional microcatheter and consequently involves a higher level of technical complexity, it extends the range of aneurysms that can be successfully treated with electrolytically detachable coils via an endovascular approach.