Important Factors for a Combined Neurovascular Team to Consider in Selecting a Treatment Modality for Patients with Previously Clipped Residual and Recurrent Intracranial Aneurysms

OBJECTIVE Intracranial residual and recurrent aneurysms can occur after surgical clipping, with risks of growth and rupture. In the past, surgical reoperation, which can be associated with higher risk than the initial operation, was the only available treatment. A combined neurovascular team that uses both surgical and endovascular therapies could maximize efficacy and outcomes while minimizing risks in these difficult cases. The indications for which surgical or endovascular treatment should be used to treat patients with residual or recurrent aneurysms, however, have not been elucidated well. We have reviewed the 10-year experience of our combined neurovascular team to determine in a retrospective manner which factors were important to treatment modality selection for patients with these residual and recurrent lesions. METHODS From 1991 to 2001, the combined neurovascular unit at the Massachusetts General Hospital treated 25 residual and recurrent previously clipped aneurysms (15 had been clipped at other centers). Only patients in whom a clip had been placed were included in the study; patients who did not have a clip placed or whose aneurysms were wrapped or coated were excluded. The radiographic studies and clinical data were reviewed retrospectively to determine the efficacy, outcomes, and factors important to the selection of treatment strategy in these patients. RESULTS The patients' clinical presentations were radiographic follow-up, 17 patients; rehemorrhage, 3; mass effect, 3; and thromboembolism, 2. The mean aneurysm recurrence or residual size was 11 mm (range, 4–26 mm). The mean interval until representation was 6.6 years (range, 1 wk–25 yr). Treatment consisted of: coiling, 11 patients; reclipping, 8; proximal parent vessel balloon occlusion, 2; extracranial-intracranial bypass with coil occlusion of aneurysm and parent vessel, 2; extracranial-intracranial bypass with clip trapping, 1; and extracranial-intracranial bypass with proximal clip occlusion of parent vessel, 1. The mean radiographic follow-up period was 11 months. Complete angiographic occlusion was found in 19 aneurysms (76%), at least 90% occlusion was found in 4 aneurysms (16%), intentional partial coil obliteration was found in 1 fusiform lesion (4%), and intentional retrograde flow was found in 1 fusiform lesion (4%). Clinical outcomes were excellent or good in 19 patients (76%). Twenty-one patients (84%) were neurologically the same after retreatment (13 remained neurologically intact, and 8 had preexisting neurological deficits that did not change). Three patients (12%) had new neurological deficits after retreatment, and one patient (4%) died. There were four complications of retreatment (16%), one of which was a fatal hemorrhage in a patient 1 month after intentional partial coil obliteration of a fusiform vertebrobasilar junction aneurysm. Factors important to the selection of treatment modality were recurrence or residual location (all posterior circulation lesions were treated endovascularly), lesion size (lesions larger than 10 mm were treated endovascularly or with the use of combined techniques), and aneurysm morphology (fusiform and wide-necked lesions were treated endovascularly or with the use of combined techniques). CONCLUSION The proper selection of surgical or endovascular treatment for residual and recurrent previously clipped aneurysms can achieve excellent radiographic efficacy with low mortality. Factors important to the selection of treatment by this combined neurovascular team were posterior circulation location, aneurysm size larger than 10 mm, and fusiform morphology, which were treated endovascularly or with the use of combined techniques because of the higher surgical risk associated with these factors. For aneurysms with lower surgical risk, such as some anterior circulation aneurysms and aneurysms smaller than 10 mm, we prefer to perform a reoperation because of superior radiographic cure without compromising the outcome.