Surgical decompression coupled with diagnostic dynamic intraoperative angiography for bow hunter's syndrome

BACKGROUND: Bow hunter's syndrome, also known as rotational vertebrobasilar insufficiency, arises from mechanical compression of the vertebral artery during the neck rotation. Surgical options have been the mainstay treatment of choice. Postoperative imaging is typically used to assess adequate decompression. On the other hand, intraoperative assessment of decompression has been rarely reported. CASE DESCRIPTION: A 52-year-old male began to see “black spots,” and experienced presyncope whenever he rotated his head toward the right. The patient ultimately underwent a dynamic diagnostic cerebral angiogram, which revealed a dominant right vertebral artery and complete proximal occlusion of the right vertebral artery with the head rotated toward the right. Subsequently, the patient underwent an anterior transcervical approach to the right C6/C7 transverse process. The bone removal occurred along with the anterior wall of the C6 foramen transversarium, followed by the upper portion of the anterior C6 body medially, and the transverse process of C6 laterally. An oblique osseofibrous band was noted to extend across the vertebral artery; it was dissected and severed. An intraoperative cerebral angiogram confirmed no existing compression of the vertebral artery with the head rotated toward the right. The patient recovered from surgery without issues; he denied recurrence of preoperative symptoms at follow-up. CONCLUSIONS: The authors report the third instance where intraoperative dynamic angiography was employed with good outcomes. Although intraoperative cerebral angiography is an invasive procedure, which prompts additional risks, the authors believe the modality affords better, real-time visualization of the vertebral artery, allowing for assessment of the adequacy of the decompression. This advantage may reduce the probability for a second procedure, which has its own set of risks, and may counteract the risks involved with intraoperative dynamic angiography.