Bow hunter's syndrome caused by accessory cervical ossification: posterolateral decompression and the use of intraoperative Doppler ultrasonography.

BACKGROUND: Bow hunter's syndrome refers to symptomatic vertebrobasilar insufficiency provoked by physiologic head rotation. CASE DESCRIPTION: We report a unique case of bow hunter's syndrome caused by an accessory cervical ossification and the first use of intraoperative Doppler ultrasonography directly upon the vertebral artery during the surgical repair. After a traumatic motor-vehicle collision, the patient developed recurrent syncopal episodes when he turned his head abruptly to the right. Transcranial Doppler studies and vertebral angiography with the patient's neck rotated into the symptomatic position revealed marked reduction of vertebral artery flow, and fine-cut CT of the upper cervical spine demonstrated the compressive accessory ossicle. Intraoperative Doppler ultrasound performed with the head in neutral and rotated positions, before and after surgical decompression, demonstrated restoration of blood flow in the vertebral artery. We discuss the mechanisms of bow hunter's syndrome and the advantages of intraoperative Doppler ultrasonography.
CONCLUSION: This case describes the first use of intraoperative Doppler ultrasonography directly upon the vertebral artery to provide an unrestricted real-time assessment of the surgical decompression for bow hunter's syndrome.