Large aneurysm in a nonbifurcating cervical carotid artery: an aneurysm associated with a rare anomaly treated with radial artery graft bypass: case report.

BACKGROUND AND IMPORTANCE: A nonbifurcating cervical carotid artery is an extremely rare type of carotid artery anomaly. We present a patient with a nonbifurcating cervical carotid artery and a large aneurysm of the cavernous internal carotid artery (ICA). The patient was successfully treated with combined microsurgical and endovascular techniques. We describe this case with reference to the relevant literature. CLINICAL PRESENTATION: A 66-year-old woman with progressive left external ocular movement dysfunction was found to have a large left cavernous ICA aneurysm. Serial magnetic resonance angiography revealed progressive growth of the lesion. In addition, conventional angiography showed a nonbifurcating cervical carotid artery and a persistent primitive trigeminal artery. The aneurysm was found unsuitable for direct surgery because of its size and location and for endovascular intervention because of extreme tortuosity of both carotid and right vertebral arteries. Surgery was performed in 2 stages. First, we performed an extracranial-intracranial high-flow bypass using radial artery graft, followed by proximal occlusion of the carotid artery. As the second stage, the patient underwent intravascular parent artery occlusion via the radial artery graft bypass to approach the intracranial carotid artery. The carotid artery was successfully coil embolized, and the aneurysm was undetectable on a postprocedure angiogram. Serial follow-up magnetic resonance imaging revealed thrombosis of the aneurysm. CONCLUSION: We report a rare case that involves the novel use of the radial artery graft bypass as an approach for parent vessel occlusion.