Neurosurgical management of inadequately embolized intracranial aneurysms: a series of 17 consecutive cases

Summary

Objective. Inadequately embolized aneurysms (IEA) are coiled aneurysms with a significant remnant (>5%), initially or after recanalisation, or with a coil extrusion deemed too thrombogenic or threatening the blood flow in the parent vessel. Our objective is to report our experience with the surgical clipping (SC) of a consecutive series of 17 IEA considered as not appropriate for an additional endovascular procedure.

Methods. Between February 1996 and April 2006, we evaluated 523 ICA in 380 patients of whom 192 underwent coil embolisation (CE), 117 with complete occlusion (61%), 47 with near complete occlusion (≥95%), 9 with partial occlusion (<95%), and 19 without any coil delivery (attempted embolisation). Of the 173 ICA embolized one or two times, at their radiological follow-up 15 (8.6%) were considered as IEA and not appropriate for an additional CE. Two IEA treated endovascularly before February 1996 were added to this series. The female/male ratio was 0.47 with an average age of 54 years (range, 37–65). All cases were located on the anterior circulation except the last one. The 17 IEA were treated by SC either because of an aneurysm remnant deemed not accessible to a further CE and large enough for direct clipping or because the risks of a thromboembolic event related to extruded coils was too high.

Results. SC was complete in all 17 cases, confirmed angiographically. Postoperatively, the clinical status of two patients deteriorated slightly but transiently. Our surgical experience with this series led us to classify IEA into five types, in three groups: group A (with one type: type A) was the most important group (n = 11) with IEA characterized by an aneurysm residue allowing direct SC, as assessed preoperatively; group B (n = 4) comprised aneurysms with a residue smaller than predicted and showing parent vessel stenosis when a clip was applied to the neck residue requiring the fundus full of coils to be removed followed by either clip application to the neck residue (type B1, n = 3) or suture if the remnant was too small (type B2, n = 1); and group C (n = 2) grouping cases requiring coil extraction through the parent vessel (type C2, n = 1) or through the fundus (type C2, n = 1).

Conclusions. With this series of IEA, we observed that open surgery of type A and C aneurysms can be a straightforward procedure. Our experience with type B IEA encourages us to wait for a sufficient aneurysm residue before performing SC because of the potential difficulties that may be encountered by the surgeon, particularly in type B2. SC of IEA was very effective with complete occlusion and no permanent morbidity in all 17 cases.