Rotational vertebral artery occlusion secondary to adjacent-level degeneration following anterior cervical discectomy and fusion.

Rotational vertebral artery occlusion (RVAO), or bow hunter's syndrome, most often occurs at the C1-2 level on physiological head rotation. It presents with symptoms of vertebrobasilar insufficiency (VBI). Several previously published studies have reported on subaxial sites of vertebral artery (VA) compression by head rotation. The authors report a case of subaxial spine RVAO due to adjacent-segment degeneration. A 52-year-old man presented with dizziness when rotating his head to the left. Twenty years earlier, he had undergone a C4-5 anterior cervical discectomy and fusion (ACDF) for a herniated disc. Imaging studies including a dynamic CT angiography and dynamic catheter angiography revealed occlusion of the left VA at the C3-4 level when the patient turned his head to the left, in the setting of an aberrant vertebrobasilar system. Successful treatment was achieved by surgical decompression of the left VA and C3-4 ACDF. Expedited diagnosis and treatment are dependent on the recognition of this unusual manifestation of RVAO, especially when patients present with nonspecific symptoms of VBI.