Cervical spine instability and canal stenosis caused by rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory process that causes symmetrical synovitis, resulting in deformities in the hands and feet’s small joints.1 The next most common abnormality is the cervical spine in 36-86% of all RA cases. Fortunately, biological therapy such as 17 infliximab (IFX) as first-line biologic treatment and 17 tocilizumab (TCZ) as a second-line biologic treatment combined with methotrexate (MTX) on rheumatoid arthritis can decrease cervical involvement to 15-30%.2,3 However, medical treatment is only preventative, if cervical abnormalities have given symptoms, then fusion surgery should be considered to stop the disease’s progression.4 Clinical manifestation range from occipital neuralgia, sensory disturbance, muscle Abstract

Published by: Indoscholar Publishing Services (www.indoscholar.com) weakness, quadriplegia, and sudden death. 5 Inflammation is a significant factor in this disorder, so the levels of C-reactive protein (CRP) in the diagnosis of rheumatoid arthritis are the risk factors for the development of atlantoaxial subluxation. 6 The high incidence of cervical instability in rheumatoid arthritis recommends that we should routinely screen cervical instability for rheumatoid arthritis patients. 7 Inflammatory synovial proliferation causing ligaments tendinous tissues laxity and bone erosion, resulting in excessive movement of the cervical joints. Damage to the transverse ligament and especially alar ligament causes a significant increase in Anterior Atlanto Dental Interval (AADI). 8 Increasing sliding motion between atlas and axis will develop atlantoaxial subluxations (AAS) 65%. Facet ligament laxity and joint surface destruction at the C3 to C7 and interspinous processes ligaments laxity create subaxial subluxation (SAS) observed in 20% and cranial settling describe in 15%. 9 Patient may have one subluxation (one of the following: atlantoaxial subluxations-AAS or Subaxial subluxation-SAS or basilar invagination/upward migration of the dens/Cranial settling of odontoid process), or combination of two or three types of involvement. 10 Medullary brainstem compression may be caused by cranial settling of odontoid process or pannus. Spinal cord compression may be caused by dynamic compression as well. The risk of irreversible paralysis is increased if the posterior atlanto-dental interval (PADI) is 14 mm or less. 5 Neural compression may progress and cause death in 10% of patients with cervical rheumatoid arthritis in post mortem studies. 11 Essential discussions have existed about the management in patients whom radiologically confirmed cervical instability in the absence or mild neck pain and neurological symptoms. 12 To avoid unnecessary surgery, some of the authors accept conservative management, cervical orthosis, and symptomatic treatment. This option may lead to late interventions, which has proved to make a worse outcome. Once myelopathy is caused by cranial settling occurs, the mortality rate increases significantly, even after adequate surgery with decompression and stabilization. Once it turns to myelopathy, 50% will die in a year. 12 In this case report, we describe a successfully managed patient with rheumatoid arthritis who developed erosive destruction of the odontoid process, anterior atlantoaxial subluxation, superior migration of odontoid, sub-axial subluxation, and cervical canal stenosis. According to Kraus's opinion, if there is a subaxial subluxation and the construct involves the suboccipital then a longer construct is carried out.

Case report
In this patient, lateral mass screws were placed from C3 to C7, and total laminectomy decompression of C3 to C6 done, which was then used as an autologous bone graft. Taking into account the individual condition of the patient in assisting post-operative rehabilitation, it was decided to maintain one segment of the segmental movement rather than fusion to T1.  A sterno-suboccipito mandibular immobilization (SOMI) orthosis was applied as postoperative immobilization for 12 weeks. She experienced gradual improvements in motoric status after the surgery.

Discussion
One of the important things is to establish the diagnosis. The diagnosis of AAS should be made by radiography examination with the patient hanging her head freely in flexion. In 50% of the cases, the subluxation is missed when the examination is made in a neutral position. 6 Lateral cervical radiograph examination in extension is needed to find atlantoaxial movement in the posterior direction. Thus we can determine whether atlantoaxial subluxation is fixed or non-fixed; it may determine therapeutic management. MRI is the best for evaluating neural compression, and the maximum extent possible of the subluxation must be considered. The apparent diffusion coefficient may be used as an indicator of spinal cord compression. 13 Soft tissue abnormalities, odontoid erosions, and AAS can be seen more clearly on 3T MRI. 14 However, the degree of magnitude of AAS often appears lighter when compared to dynamic radiography. 15 Figure 3. Pre Operation MRI assessment reveals spinal cord signal changed at C1C2 level, indicates a significant spinal cord compression. Stenosis at level C34 that occurs due to anterior listhesis C3 to C4, which can be exacerbated by flexion-extension movements.
The pannus will disappear after an immobilization of the atlantoaxial segment, and no progression of the upward migration of the dens despite the unchanged systemic course of the disease during the 5- year follow-up. 12 And there were no significant increase in the Redlund-Johnell index too. 16 Early atlantoaxial fusion seemed to

Conclusion
A thorough evaluation of rheumatoid arthritis with cervical canal involvement is essential. The therapeutical approaches are conservative and surgical. In cases where cervical rheumatoid arthritis develops neurological symptoms, the surgical approach may help the patient to reach a better outcome.