[Posterior osteosynthesis in C1-C2 instability].

This is a retrospective study of 8 cases of instability of the C1-C2 segment caused by R.A. or non-union and treated by posterior stabilization with wire loops and bone grafts. The authors reported good results in patients with mild recent neurological involvement and/or radiographic instability of the segment (posterior subluxation of the dens greater than 1/3 of the A-P diameter of C1 or tilting of the dens greater than 30 degrees). The death of a patient with non-union of the dens and severe neurological involvement due to respiratory palsy leads the authors to regard severe long-term neurological involvement (quadriparesis) a contraindication for this type of procedure.