Emergency anterior cerebral artery endarterectomy after mechanical thrombectomy failure: illustrative case.

backgroundThe neurological symptoms resulting from anterior cerebral artery (ACA) occlusions can be severe, with A2/3 occlusions reported as the most functionally impairing among medium-vessel occlusions. Patients with mechanical thrombectomy failure for acute A2/3 occlusions may occasionally require microsurgical interventions. OBSERVATIONS: An 84-year-old male presented to the authors' hospital with left lower limb paralysis. Brain CT angiography revealed a right A3 occlusion due to a calcified lesion. Alteplase was injected intravenously, and mechanical thrombectomy was performed. Navigating the aspiration catheter was difficult and the microwire was unable to pass through the lesion. Nevertheless, the authors later observed improvement in the flow of the ACA, and the paresis improved despite severe atherosclerotic stenosis. Two hours after the thrombectomy, the monoplegia deteriorated again. Therefore, the authors decided to perform microsurgical intervention. Complete ACA recanalization was achieved by performing endarterectomy for the lesion. Postoperatively, the patient was capable of walking independently. LESSONS: Microsurgical treatment is feasible for a challenging ACA occlusion with a severe calcified lesion in which an endovascular attempt is considered to be too difficult. This is the first case in which a favorable clinical outcome was reached with an emergency endarterectomy performed for A3 severe stenosis. https://thejns.org/doi/10.3171/CASE2596.