Strategies and outcomes for coiling very small aneurysms.

Objective: Coiling of aneurysms 3 mm in diameter or less has been associated with a relatively high rate of complications, including iatrogenic rupture. The present study aimed to determine the clinical outcome of our technique for coiling small aneurysms.

Methods: A retrospective chart review was performed of prospectively collected data for all patients who had endovascular coiling of an aneurysm 3 mm in diameter or less between 2003 and 2008. Follow-up imaging with magnetic resonance or catheter angiography was performed at varying intervals after coiling, ranging from 1 to 6 years after the procedure. Angiographic results were assessed using the Raymond-Roy (RR) grading system. Clinical outcomes during the same period were measured using the modified Rankin Scale.

Results: Between March 2003 and April 2008, 20 patients underwent coil embolization of an aneurysm 3 mm or smaller--17 ruptured and 3 unruptured. After the procedure, 10 aneurysms were completely occluded (RR 1), 7 had residual filling of the neck (RR 2), and 3 had residual filling of the fundus (RR 3). There were no iatrogenic ruptures. Stent assistance was used in three cases. Balloon assistance was not used. Two patients were retreated, but no aneurysm reruptured. Clinical outcomes were as expected on the basis of the presenting Hunt & Hess grade. One patient with a ruptured aneurysm died from complications related to severe vasospasm.

Conclusion: Aneurysms 3 mm in diameter or smaller can be coiled safely with the use of both bare platinum and hydrogel-coated coils. In most cases, coiling of small aneurysms can be performed without the use of adjunctive devices such as balloons or stents.