OBJECTIVETo demonstrate the indications and efficacy of balloon-assisted Guglielmi detachable coiling (BAGDC).METHODSBAGDC was used for 23 patients (19 women and 4 men; mean age, 55 yr) (17%) of a series of 136 consecutive patients who underwent Guglielmi detachable coiling of aneurysms. Every aneurysm had a wide neck, and 57% were large (11–25 mm in diameter). In each case, a nondetachable silicone balloon was advanced in the parent artery and inflated to occlude the neck of the aneurysm and stabilize the Guglielmi detachable coil delivery microcatheter at the aneurysm neck. Guglielmi detachable coils were then deposited. The balloon was then deflated to verify appropriate coil placement and stability, and finally, the Guglielmi detachable coils were detached. This process was repeated until the aneurysm was suitably embolized.RESULTSOne hundred percent aneurysm embolization was achieved in 19 patients (83%), and 95 to 100% embolization was achieved in 4 patients (17%). Twenty-two patients (96%) were at their preprocedure neurological baseline after the procedure. There were three complications in the study. One patient died after sustaining subarachnoid hemorrhage-induced vasospasm followed by a hemorrhagic infarction. She had undergone an unsuccessful clip ligation of her aneurysm. A second patient developed an intra-arterial thrombus at the site of balloon deployment. She sustained ischemic events that were treated with thrombolysis and anticoagulation. She made a complete recovery. A third patient developed an intra-arterial thrombus that was noted during the procedure. She was treated with intra-arterial thrombolysis and experienced no clinical sequelae. No permanent complications could be attributed to the BAGDC technique. The median clinical follow-up time was 10 months. No patient required additional treatment or developed a recurrent aneurysm neck or lumen.CONCLUSIONBAGDC is a promising adjunct to the treatment of wide-necked aneurysms. The balloon serves two purposes: it stabilizes the microcatheter in the aneurysm during coil delivery, and it forces the coil to assume the three-dimensional shape of the aneurysm without impinging on the parent artery.