Patients with rheumatoid arthritis (RA) often suffer from instability of the upper cervical spine. The most common instability is anterior atlanto-axial subluxation (AAS). Instability may lead to neurologic deficits from spinal cord compression and intractable pain, decreasing quality of life and its length.
This prospective study analyzed different fixation methods and the influence of atlanto-axial and occipito-cervical fusion on clinical and radiological outcome. 41 patients with RA with instability of the upper cervical spine were treated surgically for progressive instability, pain and neurological deficit. Average age of our patients was 52.4 years (21-76 years). At the time of surgery, duration of the disease was in average 18.6 years (2-47 years). Patients had advanced stage of the disease according to Steinbroker, on hands stage 3.7 and feet stage 2.9. Atlanto-axial fixation was done for AAS in 27 (24 Magerl transarticular fixations and Brooks-Jenkins technique in 3 patients). Occipito-cervical fusion was done in 13 patients (3 with Ransford loop and sublaminar wires and 9 with CerviFix). One patient was managed in halo-cast fixation. Spinal fusion was performed in all patients using autologenous bone graft. Patients were evaluated by using Functional Rating Index (FRI), Health Assessment Questionnaire (HAQ) and visual pain analogue scale (VAS) before and after surgery in set intervals, when radiological examination was also performed including dynamic films.
Three patients died in the postoperative period (3 weeks, 11 and 18 months). 38 patients remained for follow up, which was in average 28.4 months. Fusion was considered when hardware was intact and patient was satisfied, no motion was detected on dynamic X rays or bony fusion was clearly visible. Fusion was assessed in 40 patients, 32 fused, 8 had fibrous non-union. 3 of these patients had hardware failure. 9 patients had preoperatively verified panus formation peridentally, which resorbed after the surgery. FRI evaluation was done in 40 patients, 30 improved (14 patients by more than 10 points), 6 patients did not change and 4 worsened. The improvement after 3 and 12 months was statistically significant (p < 0.001). Average HAQ score decreased after surgery, but the change was not statistically significant (p > 0.05). Average VAS score decreased significantly after surgery (p < 0.05). There were 5 hardware related complications including one vertebral artery injury. None of these complications required subsequent surgery nor had any influence on good clinical outcome.
Results of FRI and VAS show the benefit from early indication of surgical stabilization of upper cervical spine in patients with RA. Based on our experience, as well as other authors, fixation of AAS by transarticular screw fixation according to Magerl is the preferred method in the younger patient group. Once destruction of the atlanto-axial joints, lateral subluxation or cranial migration of the dens is present, occipito-cervical fusion using titanium malleable implant (CerviFix) is necessary.
Positive clinical outcomes advocate early surgical intervention as described in recent literature. Surgery prevents subsequent neurological damage life quality deterioration and shortening of life expectancy.