title: Bow hunter's syndrome in the setting of contralateral vertebral artery stenosis: evaluation and treatment options.
abstract: METHODS
  A case report.
  
  
  OBJECTIVE
  To illustrate a rare case of bow hunter's syndrome in a patient with significant contralateral vertebral artery (VA) occlusive disease.
  
  
  BACKGROUND
  Bow hunter's syndrome is an uncommon condition in which the VA is symptomatically occluded during neck rotation. This case is interesting in that the patient had what appeared to be a normal right VA and occluded left VA when the head was in the neutral position. When the head was rotated 45 degrees to the left, the patient's right VA was occluded (bow hunter's finding), and it became apparent that the left VA was not completely occluded (as it appeared in the neutral position angiogram) but rather was 90% stenosed. The complete occlusion appearance in the neutral position was an angiographic phenomenon caused by competitive flow through the open right VA. When the patient rotated his head to the left, he occluded his right VA and had insufficient blood flow through the left VA, thus creating a symptomatic ischemic state.
  
  
  METHODS
  This case was studied using dynamic computed tomography imaging, single-photon emission computed tomography, transcranial Doppler ultrasound, brain stem auditory evoked potentials, and dynamic range-of-motion cerebral angiography.
  
  
  RESULTS
  The patient demonstrated bow hunter's syndrome as documented on clinical examination and history. Transcranial Doppler studies, dynamic computed tomography scanning, and cerebral/cervical angiography confirmed the diagnosis and revealed an interesting angiographic pattern, which explained the patient's symptoms and findings only when angiographic flow patterns were taken into consideration.
  
  
  CONCLUSIONS
  Bow hunter's syndrome should be suspected when a patient presents with reproducible vertebrobasilar symptoms on rotating the neck. Quantitative documentation using imaging and electroneurophysiologic tests is important when assessing this subjective process. Careful evaluation of the angiographic imagescan often help explain an odd flow pattern and provide the physician with a range of treatment options.
authors.affiliation: Department of Neurosurgery, University of Pittsburgh Medical Center-Presbyterian University Hospital, Pittsburgh, Pennsylvania 15213-2582, USA. horowitz@neuronet.pitt.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Tudor
authors.initials: T
authors.lastname: Jovin
authors.forename: Jeff
authors.initials: J
authors.lastname: Balzar
authors.forename: William
authors.initials: W
authors.lastname: Welch
authors.forename: Amin
authors.initials: A
authors.lastname: Kassam
mesh_terms: D001783:Blood Flow Velocity; D002545:Brain Ischemia / Q000175:diagnosis / Q000209:etiology; D002533:Cerebral Angiography; D016057:Evoked Potentials, Auditory, Brain Stem; D019416:Head Movements; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000503:physiopathology*; D016059:Range of Motion, Articular; D013577:Syndrome; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014102:Torsion Abnormality / Q000150:complications / Q000503:physiopathology; D017585:Ultrasonography, Doppler, Transcranial; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D014715:Vertebrobasilar Insufficiency / Q000150:complications / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*