All of the following are true about fracture of the atlas vertebra, except -

It is the most common type offracture of the Atlas. There is no encroachment on the neural canal and usually no neurological damage. CT Scan is particularly helpful in defining the fracture. The treatment is typically conservative :- Undisplaced stable injuries are managed by semirigid cervical collar or halo-vest until fracture unites. Unstable injury with transverse ligament rupture (>7 nun displacement of lateral mass) is managed by halo traction followed by halo vest immobilization for a total of 3 - 4 months. If a late instability or nonunion is present, atlanto - axial (C1 - C2) arthodesis and atlanto - occipital (cervico - occipital) fusion is done.