Atlas fractures

Fractures of the atlas account for 1 - 2% of all vertebral fractures. We di vide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolat ed fractures of the lateral mass and fractures of the transverse process. I solated fractures of the anterior or posterior arch are benign and are trea ted conservatively with a soft collar until the neck pain has disappeared. Jefferson fractures are divided into stable and unstable fracture depending on the integrity of the transverse ligament. Stable Jefferson fractures ar e treated conservatively with good outcome while unstable Jefferson fractur es are probably best treated operatively with a posterior atlanto-axial or occipito-axial stabilization and fusion. The authors preferred treatment mo dality is the immediate open reduction of the dislocated lateral masses com bined with a stabilization in the reduced position using a transarticular s crew fixation C1/C2 according to Magerl. This has the advantage of saving t he atlanto-occipital joints and offering an immediate stability which makes immobilization in an halo or Minerva cast superfluous, In late instabiliti es C1/2 with incongruency of the lateral masses occurring after primary con servative treatment, an occipito-cervical fusion is indicated. Isolated fra ctures of the lateral masses are very rare and may, if the lateral mass is totally destroyed, be a reason for an occipito-cervical fusion. Fractures o f the transverse processes may be the cause for a thrombosis of the vertebr al artery. No treatment is necessary for the fracture itself.