Traumatic spondylolisthesis of the axis treated with direct C2 pars screw.

OBJECTIVE The optimal treatment modality for traumatic spondylolisthesis of the axis is still a controversial issue. Many conservative, posterior and anterior fixation techniques have been used to treat these injuries. The C2 pars (isthmus) was used as a novel screw anchor point in upper cervical spine injuries. The direct C2 pars screws are also used to fixate the posterior and anterior parts of the C2 vertebra. METHODS Four cases with traumatic spondylolisthesis of the axis were presented. The cases were classified as type II according to Levine and Edwards' classification. C2 pars was used to fixate the posterior C2 elements to the C2 body. RESULTS While a direct C2 pars screw was used for C2 fixation in two cases, a C2 pars-C3 lateral mass screw-plate system was used in the remaining two cases. A clinical and radiological improvement was achieved in all cases. CONCLUSION It is concluded that the C2 pars can be used as screw-bone interface in upper cervical spine traumas. The direct C2 pars screw can fixate the C2 in well-selected cases. The additional C2-3 fixation increases the C2-3 stability.