Superficial Temporal Artery-to-M2 Bypass and Clip Trapping of a Ruptured Fusiform MCA Aneurysm

Fusiform intracranial aneurysms (IAs) can be challenging to treat, especially when ruptured.^1-3 Clip trapping and bypass is an important treatment modality for complex IAs not amenable to endovascular approaches (i.e., stent-assisted coiling, flow diversion), which can be limited by low occlusion rates and anatomical constraints (e.g., tortuosity, proximity to branching vessels).^4,5 Here we highlight the treatment considerations and technical steps for clip trapping and intracranial bypass of a previously ruptured middle cerebral artery fusiform aneurysm. A 76-year-old man with a history of atrial fibrillation presented with subacute progressive headaches and lower-extremity weakness one month after admission elsewhere for reported hypertensive hemorrhage. Imaging demonstrated a right-sided 4.3 × 3.0-mm fusiform IA involving the proximal nondominant anterior temporal M2 artery and subacute bilateral basal ganglia strokes, presumably from vasospasm; prior imaging showed a right peri-sylvian hemorrhage. He was neurologically intact, except for diffusely weakened lower extremities (4/5). Endovascular treatment options were dismissed because of small vessel size and his hesitance toward dual-antiplatelet therapies. Vessel sacrifice was not selected because of the stroke risk. A clip-trapping and flow-preserving bypass was selected for treatment, with superficial temporal artery (STA)-M2 selected because there was a large frontal STA donor branch and nondominant M2 recipient vessel. After uneventful surgery, postoperative imaging demonstrated complete aneurysm occlusion, a patent bypass filling the temporal M2, and no new strokes. The patient returned to his prehemorrhage baseline by 2-month follow-up. Flow-preserving cerebral bypass remains an important skill for the management of complex IAs in properly selected patients in the endovascular era.