Posterior open reduction and internal fixation of C1 fractures: the C-clamp technique

The treatment of isolated atlas (C1) fractures is still controversial. The surgical management usually involves an arthrodesis of the atlanto-axial (C1-C2) joint with or without occipital fixation. We reviewed the senior author's series of posterior only open reduction and internal fixation (ORIF) of isolated C1 fractures.

Retrospective analysis of consecutive patients with isolated C1 fractures, treated in one institution by posterior only ORIF between 2005 and 2017. All fractures of C1 with concomitant C2 or occipital condyle fractures were excluded. The C1 arch was reduced with C1 lateral mass screws, connected with a transverse rod in a C-clamp fashion. We analyzed neck pain on the visual analog scale (VAS) and imaging signs of instability on follow-up.

We identified eight patients, six males, and two females with a mean age of 37.9 years (range 20-71 years). All were neurologically intact before surgery, none had a documented transverse ligament disruption, and the mean gap between the fractured pieces was 5.3 mm. Five patients were treated < 72 h of injury, two patients had failed halo vest for 8-10 weeks, and one patient was operated after 6 months because of painful pseudarthrosis despite wearing a hard collar. One patient developed a transient neurological deficit due to vertebral artery dissection that had resolved completely at time of follow-up. The mean follow-up after surgery was 12.6 months (range 1-49 months) and mean preoperative neck pain (VAS 5.1) was significantly decreased (VAS 0.8; p < 0.001). On follow-up radiological evaluation, no instability was noted in any patient.

Posterior ORIF of C1 fractures may be an option for patients who fail or do not wish to pursue conservative management. The particular advantage of this technique over C1-C2 arthrodesis is the preserved range of rotational motion. Mono-axial screws seem to provide better reduction capacity.