Bow Hunter Syndrome: An Illustrative Case and Operative Management.

Abstract

The differential for vertebrobasilar insufficiency is wide and can be caused by posterior circulation infarcts, steal-type phenomena, or other systemic causes. In the absence of imaging findings explaining symptomology, the utility of appropriate history gathering and dynamic angiography cannot be understated in identifying Bow Hunter's syndrome, a rare cause of dynamic vertebrobasilar insufficiency. We present a case of a 69-year-old man who complained of presyncope and severe dizziness when turning his head towards the right. On examination he had no radiculopathy but did have objective evidence of myelopathy. Computed tomography imaging and dynamic angiography demonstrated C3-C4 right uncovertebral joint hypertrophy and near complete stenosis of the right vertebral artery with dynamic head position towards the right. Given vertebrobasilar insufficiency and myelopathy, he was taken to the operating room for C3-C4 anterior cervical discectomy and fusion with vertebral artery decompression (Video 1). The patient provided consent for the procedure. Standard anterior cervical neck dissection was undertaken with additional platysmal undermining to facilitate exposure of the right uncovertebral joint and transverse processes. The vertebral artery was first decompressed above and below the area of most significant stenosis at the respective transverse foramina before the hypertrophied uncovertebral joint was removed. Next, discectomy and posterior osteophyte removal were completed in typical fashion followed by graft, plate, and screw placement. Postoperatively the patient had immediate resolution of symptoms and continued so at eight month follow-up. Imaging demonstrated return to normal caliber of the right vertebral artery and successful decompression.