First-generation bypass surgery for a giant fusiform aneurysm of the middle cerebral artery: an illustrative case and surgical video.

Giant fusiform aneurysms of the middle cerebral artery (MCA) are complex and rare vascular lesions with a poor natural history and challenging treatment decision-making. We report the case of a 46-year-old male with a history of chronic hypertension and a transient ischemic attack who presented with left-sided hemiparesis. A cerebral angiotomography revealed an unruptured giant fusiform aneurysm in the M2 segment of the right MCA. After carefully evaluating the procedure's risks and benefits with the patient, he underwent a low-flow bypass surgery. An anastomosis between the superficial temporal artery and the M3 segment was performed with proximal clipping of the M2 segment. The postoperative course was uneventful, with preserved bypass patency. At follow-up, the patient was neurologically intact. This report illustrates the nuances and operative techniques for treating a giant fusiform aneurysm of the M2 segment that accounted for a preserved bypass patency and optimal patient neurological recovery.