Background: More than 200 aneurysms have been coiled at the UIC Medical Center within the last 5 years. We describe in detail the technical factors that increase the chance of complete occlusion of a cerebral aneurysm with coils. Aneurysms selected for coiling have good geometry or are in a location that is difficult to reach surgically. Patients with medical conditions that preclude surgical treatment may also undergo coiling.
Methods: Patients with aneurysms, either ruptured or unruptured, are treated under general anesthesia, fully anticoagulated and deeply paralyzed. Coiling is done under simultaneous biplane roadmapping. After the first coil has created a mesh, the aneurysm is densely packed with soft coils of decreasing diameter, until no more coils can be deployed into the aneurysm.
Results: The morbidity and mortality rates associated with the coiling procedure have continuously decreased over the last 5 years. The morphological outcomes have improved, due to extensive use of the remodeling technique and to advancements in materials, such as refinements in the coils themselves or the availability of over-the-wire balloon catheters in different sizes and hydrophilic wires with complex tip configurations. Twenty-one percent of the aneurysms were considered to be incompletely occluded immediately after coiling. Of this group, one-third of the aneurysms were found to be completely occluded on follow-up angiograms by 6 months; these have remained occluded. One-third were more than 95% occluded after the coiling procedure; in these patients, the dome was completely occluded, but there was a small neck remnant, which has remained stable in all patients on control angiograms obtained at 6 months and 1, 2, and 4 years; none have rebled. These patients are followed medically. The remaining one-third of the aneurysms in this subgroup were less than 95% occluded, although the dome was completely thrombosed. None of them have rebled, but the neck remnant in most has regrown over a period ranging from 6 months to 2 years. These patients have undergone a second treatment-either surgical clipping, permanent occlusion of the parent vessel, or repeat coiling using the remodeling technique. The overall rebleeding rate of incompletely occluded aneurysms is extremely low (less than 1%).
Conclusion: The low morbidity and mortality rates and the good morphological outcome obtained in most cases make coiling a reasonable alternative to surgical clipping in properly selected cases.