European Spine Journal

, Volume 27, Supplement 3, pp 259–263 | Cite as

Atlantoaxial dislocation and os odontoideum in two identical twins: perspectives on etiology

  • Xiangsheng Tang
  • Mingsheng TanEmail author
  • Ping Yi
  • Feng Yang
  • Qingying Hao
Case Report



There are two theories about the origin of os odontoideum: traumatic or congenital. However, most studies favor the hypothesis of traumatic theory. To emphasize the congenital theory, we report a pair of identical twins both with atlantoaxial dislocation and os odontoideum, which is believed to be a congenital defect.


We present two 14-year-old identical twins with atlantoaxial dislocation and os odontoideum. Neither of the twins had history of trauma in head nor cervical spine. We reviewed and compared the cervical radiographs of the identical twins. Posterior atlantoaxial reduction, pedicle screw fixation and atlantoaxial fusion were performed for the two twins.


Radiological examination showed the identical twins had typical atlantoaxial dislocation and os odontoideum. The twins had high similarity in the appearance of atlantoaxial dislocation and os odontoideum. The etiology of the os odontoideum in the twins is believed to be congenital. Both the twins had improvement in neurological function after surgery.


Although a great number of cases with os odontoideum have been reported to be traumatic, there are some cases believed to be congenital.


Os odontoideum Atlantoaxial dislocation Identical twins Congenital Traumatic 


Compliance with ethical standards

Source of funding

No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Conflict of interest

None of the authors has any potential conflict of interest.

Ethical approval

The study protocol was approved by the local Medical Ethics Committee.

Informed consent

Informed consent was obtained from all individual participants included in the study.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Xiangsheng Tang
    • 1
  • Mingsheng Tan
    • 1
    Email author
  • Ping Yi
    • 1
  • Feng Yang
    • 1
  • Qingying Hao
    • 1
  1. 1.Department of Spinal SurgeryChina-Japan Friendship HospitalBeijingChina

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