Atlantoaxial transarticular screw fixation with posterior wiring using polyethylene cable - Facet fusion despite posterior graft resorption in rheumatoid patients

Study Design. A comparative retrospective study on the posterior graft union and the facet fusion in atlantoaxial transarticular screw fixation. Objective. To evaluate the posterior graft union and the facet fusion in atlantoaxial transarticular screw fixation when a polyethylene ( PE) cable was used in rheumatoid and nonrheumatoid patients. Summary of Background Data. In atlantoaxial transarticular screw fixation, metal wires or cables for posterior bone graft fixation can cause intraoperative or delayed spinal cord compression. PE cables do not have the risk, but there has been no comparative report. Also, a precise evaluation on the posterior graft union and the facet fusion has not been reported. Methods. Thirty-eight patients who submitted to atlantoaxial transarticular screw fixation and posterior bone graft without any concomitant operation were followed up for more than 2 years. The posterior graft union and the facet fusion were evaluated by functional radiographs and computed tomography scans. Results. Seven patients showed the posterior graft nonunion. All of them were rheumatoid patients and received PE cable wiring for posterior internal fixation. However, 5 of the 7 cases presented stable C1-C2 with the facet fusion demonstrated by functional radiographs and computed tomography scans, achieving an overall fusion rate of 95%. Conclusion. In atlantoaxial transarticular screw fixation, the use of PE cable and rheumatoid background are 2 of the unfavorable factors for the posterior graft union. However, atlantoaxial transarticular screws can bring the facet fusion despite the posterior graft failure in such cases.