Microsurgery for brain aneurysms in an accessory A2 and basilar arteries: a rare case presentation and surgical video.

We present the case of a 58-year-old male with a 3-day history of sudden onset headache, loss of consciousness, and uncontrolled vomiting. The patient had 3/5 quadriparesis and a Glasgow coma scale (GCS) score of 8, which merited neurocritical intensive care. Brain imaging suggested the presence of two lesions: (i) a fusiform aneurysm of 12 × 7 mm in an accessory A2 artery of the anterior cerebral artery and (ii) an unruptured saccular aneurysm of 3.3 × 2.8 mm in the distal segment of the basilar artery. He was deemed a candidate for microsurgical management. Postoperatively, he had 4/5 quadriparesis, paresis of the right oculomotor nerve, and a GCS score of 13. A 3-month follow-up showed a significant improvement in neurological function with a score of 2 on the modified Rankin scale. The presented case illustrates the relevance of a nuanced acquaintance to operate in diseased anatomical variants and complex pathologies of narrow corridors.