Background: Paraclinoid aneurysms include those that are distal to the cavernous segment of the internal carotid artery and proximal to the posterior communicating artery. The purpose of this study was to review our experience with the endovascular treatment of this group of aneurysms, which are difficult to treat surgically.
Methods: Between June 1994 and April 1999, 66 patients (56 female, 10 male) with a mean age of 50.1 years (range 13-75, median 51) underwent endovascular treatment for 71 paraclinoid aneurysms. The mean size of the dome was 8.9 mm (range 3-25 mm, median 7) and the of neck was 3.8 mm (range 1.4-8 mm, median 4). Thirteen patients presented with acute subarachnoid hemorrhage, and 4 with previous subarachnoid hemorrhage. Six aneurysms produced mass effect with visual symptoms, 4 presented with transient ischemic attacks, and 44 were incidental. Nine patients had had previous unsuccessful surgery. All procedures were performed under general anesthesia and with systemic heparinization.
Results: Ninety endovascular procedures were performed on 71 aneurysms: GDC coiling in 78 (including 45 with the remodeling technique), permanent balloon occlusion in 9, and 3 had both GDC coiling and permanent balloon occlusion. In ten aneurysms it was not possible to place coils in the lumen of the aneurysm with the available technology and balloon occlusion was not indicated. Five of these were treated surgically and 5 remain untreated. All patients had immediate post procedure angiography. Of the 61 aneurysms that were treated, 46 (75%) have angiographic follow-up of 6 months or more. Morphological outcome following endovascular therapy for 61 aneurysms at last available follow-up showed > 95% occlusion in 52/61 (85.2%) and <95% in 9/61 (14.8%). Eight patients required surgery, 2 for partial coiling, 2 for refilling of a neck remnant, 2 for persistent mass effect and 2 for coil protrusion. In the 90 procedures performed, 2 (2.2%) patients had major permanent deficits (1 monocular blindness, 1 hemiparesis), 1 (1.1%) had a minor visual field cut, and 2 (2.2%) patients died from major embolic events.
Conclusion: Properly selected paraclinoid aneurysms can be successfully treated by endovascular technology. The morbidity and mortality rate of the endovascular approach in our experience is equal to or better than the published surgical series of similar aneurysms. We recommend that the endovascular approach be given primary consideration in the treatment of paraclinoid aneurysms.