title: Bipartite atlas in a collegiate football player - Not necessarily a contraindication for return-to-play: A case report and review of the literature.
abstract: BACKGROUND
  Congenital malformations of the posterior arch of the atlas are rare, occurring in 4% of the population. Anterior arch aplasia is extremely rare and often only coexists with posterior arch anomalies, resulting in a split or bipartite atlas. This congenital anomaly is believed to be present in only 0.1% of the population.
  
  
  METHODS
  A 19-year-old male collegiate football player presented with neck pain and upper extremity paresthesias after sustaining a tackle that forced neck hyperextension. Computed tomography revealed significant congenital bony anomalies of the cervical spine, with incomplete fusion of the anterior and posterior arches of the atlas; however, there was no evidence for of any acute traumatic injury or fracture. Magnetic resonance imaging revealed increased edema in pre-vertebral soft tissues around C1-C2, with a possible increase in signal within the fibrous ring of the anterior C1 ring. Flexion and extension imaging confirmed reduced range of motion and no instability. Patient was treated non-operatively, and was able to resume normal activity and training regimens, and continued to do well clinically.
  
  
  CONCLUSIONS
  We describe a rare case of split or bipartite atlas in collegiate football athlete who sustained a neck injury during a tackle. The patient had no atlanto-axial instability or other clinical contraindications and was managed non-operatively, resuming full participation shortly thereafter with a full resolution of symptoms.
authors.affiliation: Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Petraglia
authors.forename: Sean M
authors.initials: SM
authors.lastname: Childs
authors.forename: Corey T
authors.initials: CT
authors.lastname: Walker
authors.forename: Jeffery
authors.initials: J
authors.lastname: Hogg
authors.forename: Julian E
authors.initials: JE
authors.lastname: Bailes
authors.forename: Mathew W
authors.initials: MW
authors.lastname: Lively