title: Helical computed tomography and three-dimensional reconstruction of a bipedicular developmental anomaly of the C2 vertebra.
abstract: METHODS
  A case of bilateral failure of fusion of the C2 neural arch resembling a bipedicular fracture in a 9-year-old boy involved in a motor vehicle accident.
  
  
  OBJECTIVE
  To describe the use of helical computed tomography and three-dimensional reconstruction images to identify the defect as congenital.
  
  
  BACKGROUND
  Congenital defects in the C2 neural arch are rare. Diagnostic difficulties arise when they are discovered during the assessment of patients after trauma, when they may resemble C2 arch fractures.
  
  
  METHODS
  Lateral cervical spine radiograph, transverse section computed tomography, and three-dimensional reconstruction images were used to delineate the anatomy of the defect.
  
  
  RESULTS
  The three-dimensional reconstruction views showed that normal alignment of the vertebrae was maintained, despite the pedicle defects.
  
  
  CONCLUSIONS
  Differentiation of a C2 fracture from a congenital defect may be difficult. Reconstruction in three dimensions from helical computed tomography is a useful adjunct to conventional computed tomography in the evaluation of such patients.
authors.affiliation: Department of Orthopaedic Surgery, Addenbrooke's Hospital, Cambridge, United Kingdom. dominicpower1@hotmail.com
authors.forename: D M
authors.initials: DM
authors.lastname: Power
authors.forename: J L
authors.initials: JL
authors.lastname: Cross
authors.forename: N M
authors.initials: NM
authors.lastname: Antoun
authors.forename: D
authors.initials: D
authors.lastname: Edwards
mesh_terms: D002574:Cervical Vertebrae / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002648:Child; D003937:Diagnosis, Differential; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008953:Models, Anatomic; D013122:Spinal Diseases / Q000151:congenital* / Q000000981:diagnostic imaging*; D016103:Spinal Fractures / Q000175:diagnosis; D014057:Tomography, X-Ray Computed / Q000379:methods*