title: The effect of posterior bridging of C-1 on craniovertebral junction surgery.
abstract: OBJECTIVE
  The groove for the vertebral artery (VA) may be bridged on C-1, forming a canal through which the artery passes. Because this variant may significantly affect the commonly performed C-1 posterior laminectomy, the authors studied the incidence and radiological appearance of this anatomical feature in surgical specimens.
  
  
  METHODS
  Anatomical measurements were performed using a Vernier caliper (accurate to 0.1 mm) on 166 dry C-1 vertebrae. In addition, a convenience sample of 172 cervical x-ray films was evaluated. Partial osseous bridging was detected in eight (4.8%), and a complete osseous bridge, forming the canalis arteriae vertebralis (canal for the VA), was seen unilaterally (eight on the left and two on the right) in 10 (6%) and bilaterally in eight (4.8%) of the dry vertebrae. On lateral radiography, a complete bone bridge was observed on nine (5.2%) and a partial bridge on 10 (5.8%) of the 172 studies.
  
  
  CONCLUSIONS
  The discovery of a common variant may necessitate an immediate change in surgical management, and this anomaly could even increase the rate of surgery-related complications. The VA canal, present in the C-1 vertebra in approximately 5% of the specimens evaluated, was a variant that may be protective against VA injury. Knowledge of this variant may help the surgeon undertaking procedures in the C-1 region.
authors.affiliation: Department of Neurosurgery, Anatomy, Orthopaedics, and Family Medicine, Kahramanmaras Sutcuimam University Medical School, Kahramanmaras, Turkey. mehmetsenoglu@hotmail.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Senoglu
authors.forename: Yakup
authors.initials: Y
authors.lastname: Gümüşalan
authors.forename: Kasim Zafer
authors.initials: KZ
authors.lastname: Yüksel
authors.forename: Murat
authors.initials: M
authors.lastname: Uzel
authors.forename: Mustafa
authors.initials: M
authors.lastname: Celik
authors.forename: Davut
authors.initials: D
authors.lastname: Ozbag
mesh_terms: D000328:Adult; D001269:Atlanto-Occipital Joint / Q000601:surgery; D001837:Body Weights and Measures; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D015994:Incidence; D007796:Laminectomy; D008297:Male; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies; D013127:Spinal Nerves / Q000000981:diagnostic imaging / Q000473:pathology; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000473:pathology