A rare case of nonbifurcating left common carotid artery associated with bilateral internal carotid artery anastomosis: a case report

BACKGROUND: This study reports a rare case of a nonbifurcating carotid artery with bilateral internal carotid artery anastomoses. Special anatomical features related to nonbifurcating carotid arteries are comprehensively summarized. The embryological causes and potential clinical significance of this variation are discussed. MATERIALS AND METHODS: An anatomical variant of the left common carotid artery was discovered in a middle-aged elderly Chinese female cadaver during standard dissection in an anatomy course. RESULTS: The left common carotid artery was unbranched; instead, it continued intracranially as the internal carotid artery and gave rise to branches of the external carotid artery. In the sella turcica region, bilateral internal carotid arteries developed aberrant anastomoses, which is even rarer. Furthermore, both posterior communicating arteries arose from the left posterior cerebral artery and were accompanied by multiple large intracranial aneurysms. According to a thorough literature review, this is the first documented instance of this complex combination of variants. CONCLUSIONS: This study demonstrates that abnormal vascular embryogenesis can lead to complex vascular variants. Clinicians should remain vigilant for potential hemodynamic irregularities and take prompt action to prevent larger aneurysms from forming and enlarging. Precise identification and thorough preoperative evaluation are crucial for reducing surgical risks and avoiding serious complications, such as infarction. Detailed knowledge of these variations is critical for imaging, interventional procedures, and surgery involving the cervical and cerebral vessels.