MCA-to-MCA Bypass with Interposition Graft for Ruptured Mycotic Middle Cerebral Artery Aneurysm.

Mycotic aneurysm, also referred to as infected aneurysm, is a rare entity that may result from the bacterial infection or infective endocarditis. The treatment options include conservative medication and endovascular or direct microsurgical intervention. However, the optimal strategy remains unknown and cerebral revascularization may be required in some rare cases. In this surgical video, we demonstrate a distal middle cerebral artery (MCA) mycotic aneurysm that we treated by intracranial-intracranial bypass with an interpositional graft. Our patient is a 53-year-old male who presented with a 6-day history of severe headache. He was subsequently admitted to our institution. Preoperative computed tomography angiography showed a left temporal hematoma (>30 mL) and an opercular segment of the MCA (M3) aneurysm, which was highly suspicious for mycotic origin. A standard frontotemporal craniotomy was carried out with preservation of superficial temporal artery (STA). Following the sylvian fissure dissection, the aneurysm was exposed with the characteristics of a thick wall and an undefinable neck, which made direct clip application difficult. The aneurysm was resected initially, and 2 cut ends were reconnected by an STA graft. Following arterial reconstruction, intraoperative Doppler revealed a patent status of the interpositional graft vessel. Postoperatively, no neurologic deficit was observed and computed tomography angiography demonstrated total elimination of the aneurysm without stenosis of the graft vessel. Low-molecular dextran was prescribed rather than aspirin, as there was concern for hemorrhage. Antibiotic treatment was used for at least 4 weeks, and the patient was transferred to the inpatient cardiology team for management of endocarditis. A 4-month follow-up angiogram showed a patent STA and excellent left distal MCA blood flow (Video 1). The favorable outcome of this case revealed that MCA-to-MCA bypass with interpositional graft is a safe, effective method for the unclippable cerebral aneurysm. As other authors have asserted, a full dose of long-term antibiotic therapy remains essential following intervention. Meanwhile, dextran has proved to be a viable alternative for anticoagulation during perioperative management of bypass surgery..