title: Posterior C1 stabilization using superior lateral mass as an entry point in a case with vertebral artery anomaly: technical case report.
abstract: BACKGROUND
  This is the first report of using the superior lateral mass as an alternative starting point for C1 posterior screw placement, demonstrating the importance of recognizing vertebral artery (VA) anomaly in deciding the surgical strategy for C1 screw placement.
  
  
  METHODS
  A 56-year-old man presented with severe neck pain after a fall. Imaging demonstrated an unstable bursting fracture at C4, C1-2 instability, and a subluxation at C2-3. Computed tomography angiography indicated that the persistent first intersegmental artery was located on the left side. The patient underwent anterior-posterior cervical fixation and fusion. Posterior C1 fixation was done with polyaxial screw rod construct using C1 superior lateral mass on the left side and C1 inferior lateral mass on the right side. The patient had no immediate postoperative deficits. At the 8-month follow-up examination, the patient was neurologically intact with a solid cervical fusion.
  
  
  CONCLUSIONS
  The third segment of the VA is heterogeneous; therefore, preoperative radiologic studies should be performed to identify any anatomical variations. Using preoperative 3-dimensional computed tomography angiography, we can precisely identify an anomalous VA, thereby significantly reducing the risk of VA injury. To avoid significant morbidities associated with VA injury, a more optimal entry point for C1 fixation can be selected if a persistent first intersegmental artery or fenestrated VA is detected.
authors.affiliation: St Vincent's Hospital, Department of Neurosurgery, Catholic University of Korea, Suwon, South Korea. jatagi15@paran.com
authors.forename: Jae Taek
authors.initials: JT
authors.lastname: Hong
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Jang
authors.forename: Il Sup
authors.initials: IS
authors.lastname: Kim
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Yang
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Sung
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Son
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
mesh_terms: D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D007593:Joint Instability / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D013123:Spinal Fusion / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000601:surgery*