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.^1-3 The treatment options include conservative medication and endovascular or direct microsurgical intervention.^1,4,5 However, the optimal strategy remains unknown and cerebral revascularization may be required in some rare cases.⁶ 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.⁷ Meanwhile, dextran has proved to be a viable alternative for anticoagulation during perioperative management of bypass surgery.^8,9.