Surgical treatment for atlantoaxial dislocation in rheumatoid arthritis

English Keywords:Rheumatoid arthritis  Atlantoaxial dislocation  Atlantoaxial fusion  Occipitocervical fusion  Instrumentation  Reduction

English Abstract:

  【Abstract】 Objectives： To summarize the clinical outcomes of surgical treatment of atlantoaxial dislocation in rheumatoid arthritis(RA). Methods： We retrospectively analyzed the clinical and radiographic records of 57 patients(43 femals, 14 mals) with an average age of 61.8±12.4 years(46-79 years) between January 2010 and December 2018. The course of rheumatoid arthritis ranged from 2.5 to 36.8 years, with an average of 17.5±3.7 years. The time from first diagnosis of RA to symptoms of upper cervical spinal cord compression ranged from 1.5 to 19.4 years, with an average of 8.9±2.4 years. Posture abnormalities and movement disorders occurred frequently. The American Spine Injury Association(ASIA) impairment scale: 3 cases of B degree, 12 cases of C degree, 20 cases of D degree, 22 cases of E degree. The JOA score was 4 to 14 points, with an average of 8.7±1.8. The visual analogue scale(VAS) was 4 to 10 points, with an average of 7.4±1.5. There were 44 cases of anterior atlantodental interval(AADI>10mm, 8 cases), 9 cases of posterior atlantoaxial dislocation and 4 cases of instability. In them, 6 cases were with instability of the lower cervical spine, and 10 cases with other deformities of the craniovertebral junction. For the surgical treatment, 13 patients were treated with occipital cervical fusions(group A). The other 44 patients were treated with atlantoaxial fusion: 16 patients underwent anterior transpharyngeal decompression before posterior atlantoaxial fusion(group B), 28 patients were treated with posterior atlantoaxial fusion(group C). All patients were followed up regularly for clinical signs, symptoms and improvement of neurological function. The atlantoaxial reduction and bone graft fusion were also observed. Results： No intraoperative vertebral artery injury or spinal cord injury was founded． All 57 patients were followed up for an average of 34.4±10.3 months(range, 12-84 months). In group A, the operation time was 100-130min with an average of 118.2±13.5min, and the amount of blood loss was 100-300ml with an average of 190.5±42.8ml. In group B, the operation time was 180-240min with an average of 221.4±20.3min, and the amount of blood loss was 100-260ml with an average of 157.3±36.1ml. In group C, the operation time was 100-130min with an average of 109.4±12.1min, and the amount of blood loss was 100-200ml with an average of 124.1±32.7ml. Twelve months after surgery, all patients were improved, with 3 cases from B to C degree, 6 cases from C to D degree, 3 cases from C to E degree and 9 cases from D to E degree. JOA scores were improved to 10-17(mean, 14.6±3.5), and VAS scores were improved to 1-5(mean, 3.6±1.4). The postoperative AADI was reduced to 2-3mm(mean, 2.4±0.4mm). Solid bony fusion was achieved in 56 patients at 12 months after operation, but partial absorption of the bone graft occurred in one case． There was no screw loosening, displacement, instability or breakage. Postoperative cervical spine MRI showed that the sagittal cervical spine alignment was restored, cerebral spinal fluid line was clear in the odontoid process area and no spinal cord compression was found. Conclusions： Early surgical fusion is recommended for atlantoaxial dislocation with instability and cord compression in RA. Good clinical outcomes can be achieved by posterior atlantoaxial fusion or occipitocervical fusion according to the motion range of the occipito-atlantal joint.