Introduction: The management of very large and giant intracranial aneurysms (VLGAs) has greatly evolved in the last decade. As endovascular techniques become more adapted to treat these challenging lesions, surgical intervention has become less common place. However, the middle cerebral artery (MCA) VLGAs remain as a predominantly surgical lesion at our institution.

Methods: We conducted a retrospective review from January 2000 to December 2015 of VLGAs of the MCA including patients >18 years of age that were treated at our institution. VLGA was defined as 17mm or greater in at least one dimension on CTA or DSA. The Glasgow Outcome Scale was scored at discharge (GOSd) and at 6 month or greater follow up (GOSf).

Results: Of the 545 MCA aneurysms identified during this time frame, 51 patients (9%) qualified as a VLGA. One patient did not receive treatment, leaving 50 VLGAs treated with either surgery alone (n=44, 88%), endovascular techniques (n=4, 8%), or a combination of the two modalities (n=2, 4%). Sixty-four percent of these VLGAs presented as an unruptured lesion. Predictably, the unruptured patients fared better (GOSd and GOSf =4) than those presenting with a hemorrhage; 75% vs. 22% GOSd (p=0.0004) and 76% and 58% GOSf (p=0.28), respectively.

Conclusions: Very large and giant aneurysms are well known to have a grim prognosis. Endovascular means of treating these lesions is quickly improving, but for VLGAs of the MCA surgery is currently the gold standard. This cohort is the largest sample of VLGAs of the MCA that we have found reviewed in the literature, and demonstrates superior outcomes to the natural history of the disease for both ruptured and unruptured aneurysms.

Patient Care: This review focuses on a surgical series of very large and giant aneurysms of the middle cerebral artery. It sets a benchmark for the results of future management of these lesions.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) understand the challenges faced with treating VLGAs of the MCA, 2) discuss in small groups the advantages and disadvantages of the various means of treating VLGAs of the MCA, 3) identify which treatment modality is best suited for a given VLGA of the MCA.

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