title: True oblique axis fracture associated with congenital anomalies of the upper cervical spine: Case report of an unusual fracture pattern.
abstract: BACKGROUND
  Acute traumatic axis fractures are common cervical spine injuries often caused by road accidents or falls. They are usually classified into three different types, namely, odontoid fractures, Hangman's fractures, and miscellaneous fractures. Congenital malformations of the craniovertebral junction (CVJ), although typically asymptomatic, may result in neural compression or instability, especially following trauma. Here, the authors present an unusual oblique axis fracture occurring in conjunction with several malformations of the upper cervical spine.
  
  
  METHODS
  Following a motor vehicle accident, a 25-year-old female's radiographic studies showed an oblique axis fracture involving both the anterior and posterior elements along with an anterior and posterior Klippel-Feil syndrome (KFS) anomaly. Following treatment in a halo vest, the patient maintained alignment, and ultimately the fracture was fused.
  
  
  CONCLUSIONS
  True oblique fractures of the axis are rare, as in the case presented, and may occasionally occur in conjunction with KFS of the upper cervical spine.
authors.affiliation: Section of Neurosurgery Hospital, CMQ Premiere, Puerto Vallarta, Mexico.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Robles
keywords: C2 fracture; Klippel–Feil syndrome; craniovertebral congenital anomalies; miscellaneous axis fractures; oblique axis fracture