Cl-C2 Transarticular Screw Fixation for Atlanto-Axial Instability: A Six-Year Experience

Objective:

To retrospectively review a six–year experience of one neurosurgeon utilizing the technique of Cl–C2 transarticular screw fixation for atlanto–axial instability in 73 consecutive operations.

Methods:

The study group was composed of 41 men and 32 women whose mean age was 44 years (range 8–76). The cause of the atlanto– axial instability was traumatic in 27(37%) patients, rheumatoid arthritis related in 21(29%) patients, congenital in 9(12%) patients, and pseudoarthrosis related in 16(22%) patients. All patients underwent placement of bilateral Cl–C2 transfacet screws and posterior tension band arthrodesis. Eight patients underwent unilateral screw fixation because of an aberrant vertebral artery. Patients were maintained in a rigid cervical orthosis for a mean of 11 weeks (range 8–15); a subset of 5 patients were immobilized with halo fixation for a mean of 13 weeks (range 0–16). The follow–up period averaged 2.4 years (range 1–5.5 years).

Results:

Osseous fusion was obtained in 71 patients (97%). Two patients developed pseudoarthrosis, one of whom required subsequent occipital– cervical fusion. Other complications included two wound infections (one graft site, one posterior cervical); four patients developed suboccipital numbness. There were no vertebral artery injuries, dural lacerations, spinal cord or hypoglossal nerve injuries, or broken screws.

Conclusions:

Cl–C2 transarticular screw fixation with posterior tension banding offers a 97% fusion rate with low incidence of complications. This report provides a detailed analysis of this technique and focuses on the nuances of patient evaluation and surgical landmarks in order to minimize complications.