Giant aneurysms of the anterior circle of Willis: Management outcome of open microsurgical treatment

BACKGROUND There is no uniform agreement to date regarding the optimal management of giant aneurysms (GAs) of the anterior circle of Willis. Endovascular therapeutic techniques have yielded unacceptable rates of aneurysm growth and recanalization (endosaccular) or high rates of complications (distal parent vessel occlusion). Despite size, frequent thrombosis and calcification (incollapsibility), and splaying of parent vessels, these aneurysms are readily amenable to direct surgical exposure and control of parent vessels intracranially. Published series have not considered these lesions separately and have often reflected a mixture of management strategies for these and other GAs. METHODS Thirty-eight consecutive patients with symptomatic GAs of the anterior circle of Willis were managed by the senior author over a 7-year period. Twenty-six of these patients (68%) presented with subarachnoid hemorrhage (SAH). Temporary occlusion was performed under a protocol to enhance brain protection. Direct clip reconstruction or trapping was used in all instances, with intraoperative angiographic control. Revascularization procedures and suture vascular reconstructions were not used in any case. RESULTS All patients were considered for direct microsurgical treatment. One patient refused surgery, and two patients were deemed a prohibitive medical risk. Thirty-five patients were treated surgically with complete obliteration of the aneurysm in 34 cases (97%), and patency of all parent arteries in 30 cases (86%). Overall mortality was 6% in the surgical cohort, with good or excellent clinical outcome in 71%. Mortality and poor outcome occurred exclusively in the setting of recent hemorrhage. CONCLUSIONS The results are compared to the natural history of these lesions and to the outcome (safety and effectiveness) of currently available endovascular techniques. This experience supports direct microsurgical intervention as the primary therapeutic modality for these lesions.