Rheumatoid arthritis (RA) is a chronic disease that affects approximately one percent of the U.S. population. RA is an autoimmune disease that results in the inflammation and destruction of the synovial tissue, or special cells and tissue that form the lining of the joints in the body. RA can and often does affect almost every joint in the body, especially as people get older. Although RA affects the joints of the hands and legs which can severely decrease function and mobility, people with significant disease in the spine are at risk for neurologic damage such as paraplegia, in addition to problems with pain, mobility and function. Rheumatoid disease of the spine is most common in three regions and causes distinct clinical problems. The first is basilar invagination, a condition in which arthritic destruction at the base of the skull causes the skull to “settle” into spinal column causing a pinching of the spinal cord between the skull and the 1st cervical vertebrae. The second condition, and the most common, is atlanto-axial instability. A synovitis and erosion of the joint and ligaments connecting the 1st (atlas) and 2nd (axis) cervical vertebrae causes instability of the joint, which may lead to a dislocation and spinal cord compression. In addition, localized mass/swelling of rheumatoid synovial tissue can also form at this location causing even more spinal cord compression. The third clinical scenario is called subaxial subluxation and involves bony and ligamentous destruction of the lower cervical vertebrae (C3-C7) causing instability and/or spinal stenosis.
How is it diagnosed?
The diagnosis of rheumatoid arthritis can generally be made with a thorough history and detailed physical examination. The diagnosis is confirmed with specific laboratory tests as described above. Cervical X-rays and additional imaging tests such as MRI and CT scans are generally necessary to determine if the disease is affecting the cervical spine, as well as to evaluate the severity.
What are the treatment options?
The general treatment for rheumatoid arthritis is typically managed by a rheumatologist or primary care physician. Patients with disease affecting the cervical spine are generally managed by spine surgeons with advanced training in cervical surgery and rheumatologic disease. Patients with cervical disease who do not have instability or stenosis can usually be managed with medical (non-operative) treatments, yet should continue to be followed regularly by a spine surgeon. The common medical treatments for rheumatoid arthritis are listed below.
- Nonsteroidal anti-inflammatory drugs – ibuprofen, etc.
- Analgesic drugs – acetoaminophen, hydrocodone, etc.
- Glucocorticoids (steroids) – prednisone, etc.
- Disease modifying antirheumatic drugs (DMARDs) – methotrexate, sulfasalizine, gold, etc.
- Biologic response modifiers – etanercepts, infliximab, etc.
- Protein-A immunoadsorption therapy – removal of antibodies from the blood
When a patient with rheumatoid arthritis develops cervical instability and/or spinal stenosis with myelopathy, surgical intervention is considered. The goal of surgery is to stabilize the spine and remove the compression from the spinal cord, to improve a patient’s pain and level of function and to prevent further deterioration of function and worsening pain. A patient with isolated cranial settling and/or atlanto-axial instability without cord compression can be treated with posterior occipital-cervical fusion with instrumentation. However, patients with severe anterior cord compression from a pannus at the C1-C2 joint will be indicated for a transoral decompression surgery combined with a posterior occipital-cervical fusion with instrumentation. Patients with subaxial subluxation may have instability or stenosis, or both. Treatment options vary depending on each patient’s clinical and radiographic presentation. Patients with subaxial instability may only require a spinal fusion. Patients with stenosis and myelopathy require surgical decompression and often fusion as well. If the majority of pressure is coming from osteophytes in the front of the spine, then an anterior corpectomy with strut graft and fusion may be considered. If the majority of the compression is occurring due to ligamentum flavum hypertrophy in the back part of the spinal cord, then a laminectomy or laminaplasty may be performed. Occasionally, patients with severe, multiple level stenosis and instability will require both front (anterior) and back (posterior) of the neck surgery to adequately decompress and stabilize the spine. Generally, a cervical spinal fusion will always be required and recommended in addition to the decompression component. Spinal instrumentation will typically be utilized to impart immediate stability and increase the rate of bone healing and mending. There is a higher rate of improvement for rheumatoid patients with cervical instability and/or neurologic dysfunction treated surgically than those treated nonsurgically. However, careful preoperative evaluation and delicate perioperative and postoperative management is particularly important to ensure success and avoid complications.