Bony cervical disease in rheumatoid arthritis

The cervical spine, which begins at the base of the skull, is commonly affected in rheumatoid arthritis (RA)¹. The cervical bones – the vertebrae – are smaller in size when compared to other spinal vertebrae and the purpose of the cervical spine is to contain and protect the spinal cord, support the skull, and enable diverse head movement (e.g. rotate side to side, bend forward and backward).

Atlantoaxial subluxation (AAS) is also a well recognised association of RA. This is a condition in which the vertebrae of the cervical spine are malaligned with the potential to cause neural damage, paralysis, or even death. It involves increased mobility at the joint where the first cervical vertebrae meets the second (the atlantoaxial joint).

Cervical disease in rheumatoid arthritis occurs commonly with anything between 15 to 86 per cent of patients showing radiological evidence of involvement as the disease progresses^2,3,4. This variation in the quoted prevalence could reflect differing diagnostic criteria applied and up to 50 per cent of cases may be initially asymptomatic^2,4.

Cases can be easily overlooked in a clinician’s day to day practice with the potential for life-threatening complications such as destruction of spinal cord tissue – compressive myelopathy⁵. In addition, patients may have evidence of radiological disease but remain asymptomatic for a number of years.

Pathophysiology of rheumatoid arthritis

In the early stages of rheumatoid arthritis, cervical involvement mainly occurs in the upper cervical spine in the form of AAS^4,5. AAS is most common anteriorly, but could occur posteriorly, laterally or involve rotatory displacement. With disease progression, joint destruction can lead to vertical instability or cranial settling. In addition, as involvement of the middle and lower cervical spine ensues, subaxial instability can result^3,4. Changes can also occur concurrently, particularly in patients with severe erosive disease.

The pathophysiology of the spinal problems in RA are primarily related to loss of articular cartilage, ligamentous destruction and bony erosion. Direct neuronal tissue compression can also occur due to periodontoid pannus formation and the bony impingements caused by the cervical instability⁶.

Neurological findings

Neurological deficits can occur at any phase. Sensory symptoms in the setting of RA may be mistakenly attributed to entrapment neuropathies, peripheral neuropathy or mononeuritis multiplex. However, isolated sensory symptoms (e.g. paresthesias of the hands and feet) are common presenting features of rheumatoid cervical myelopathy⁴. The onset of cervical myelopathy can therefore be missed if other features are not specifically looked for.

Some other features that could flag up cervical involvement in rheumatoid arthritis include:

• Painful limitation of neck motion
• Sub-occipital (C2) radicular pain
• Clumsiness of the hands
• Urinary incontinence or retention.

Neurological examination may also reveal pyramidal tract signs like hypertonia, hyperreflexia, upgoing planters and a spastic gait. Joint position sense may also be impaired⁶.

General management goals

The general goals of management for the RA patient with cervical disease are aimed at pain relief, achievement of spinal stability, and decompression of neural structures⁶. It involves conservative measures with or without surgery.

Conservative management

Most cases require only conservative management unless pain and neurologic deficits ensue⁷. Some conservative approaches employed include bed rest, analgesia, Philadelphia (cervical) collars, cervical traction methods (e.g. GardnerWells tongs and halo frame stabilisations plus body jackets⁶).

Surgical management

The more traditional surgical indications include intractable pain and reversible neurologic deficits. The various forms of instability pose their own set of risks of neurologic injury, and may require an individualised approach to surgical management where deemed appropriate⁶. Some open surgical approaches employed include screw and wire fixations, cervical fusion, occipitocervical fusion, neuronal/spinal decompression surgeries etc. In the case of an isolated AAS, fusion may be restricted to the C1/C2 segment.

A comprehensive review of the individual indications for – and controversies of – current surgical practice as relates to cervical spine disease in rheumatoid arthritis is beyond the scope of this article. However, the literature does suggest that if patients show clear symptoms of myelopathy, conservative treatment would not stop disease progression¹.

The Ranawat classification is a basic but useful functional assessment tool in patients with rheumatoid myelopathy. It can assist in planning patient management and assessing subsequent response (Table 1)^6,7,8.

Mortality risk

Attention is being redirected to the possibility that AAS, though usually of earlier onset than cranial settling and subaxial instability, may not sit so comfortably in the benign end of the spectrum of rheumatoid cervical disease. Neutral positioning of the neck is advised during surgery with care being taken during anaesthetic procedures to avoid further trauma to the atlantoaxial joint. Quadriplegia or respiratory compromise can occur in the more advanced cases of upper cervical involvement⁶.

A study reviewed 241 patients with confirmed RA for any evidence of radiological cervical involvement. An association suggesting up to eight times higher total mortality in patients with AAS compared to those without AAS was noted. The proximate cause of death stated in death certificates could not be verified for all cases in the absence of post-mortem, but in general, cervical disease was not mentioned as contributory to death⁵.

An earlier study reported on the postmortem findings of 104 patients with RA and atlantoaxial dislocation. Compression at the cervicomedullary cord level was noted in 11 patients and seven of the 11 had died suddenly⁹.

Most asymptomatic AAS cases would be approached conservatively in current practice. Markers like a posterior atlanto-dens interval of ‰¤14millimetres may bear better correlation with existing neurologic deficit^3,4. Attempts to identify those patients with imminent neurological deficit have been more evasive. Further robust evidence correlating asymptomatic AAS with clinically significant increased risk of mortality is required before a more aggressive approach to treatment can be advocated.

Conclusion

Careful and serial clinical evaluations are needed for patients with rheumatoid arthritis and reviews of radiological films should be undertaken, particularly when clinically unanswered questions remain. Common associations can still be overlooked in our daily practice and we must maintain a high index of suspicion. The transformation from an asymptomatic to a symptomatic, and potentially life threatening, cervical disease need not be a dramatic one.

Dr Olayinka Ogundipe

References

1. Kothe R, Wiesner L, Ruther W. Rheumatoid arthritis of the cervical spine. Current concepts for diagnosis and therapy. Orthopade 2002; 31(12): 1114-22. [Translated article from German]
2. Fujiwara K, Owaki H, Fujimoto M, et al. A long-term follow-up study of cervical lesions in rheumatoid arthritis. J Spinal Disord. 2000; 13(6): 519-26
3. Monsey RD. Rheumatoid Arthritis of the Cervical Spine. J Am Acad Orthop Surg. 1997; 5(5): 240-48
4. Keersmaekers A, Truyen L, Ramon F, et al. Cervical myelopathy due to rheumatoid arthritis. Case report and review of the literature. Acta Neurol Belg. 1998; 98(3): 284-8
5. Riise T, Jacobsen BK, Gran JT. High mortality in patients with rheumatoid arthritis and atlantoaxial subluxation. J Rheumatol. 2001; 28(11): 2425-9
6. Alberstone CD, Benzel EC. Cervical spine complications in rheumatoid arthritis patients. Awareness is the key to averting serious consequences. Postgrad Med. 2000; 107(1) 199-200, 205-8.
7. Thonse R, Belthur M. Rheumatoid arthritis and neck pain. Postgrad Med J 2003; 79: 711, 713-14.
8. Ranawat CS, O’Leary P, Pellicci P, et al. Cervical spine fusion in rheumatoid arthritis. J Bone Joint Surg Am 1979; 61(7): 1003-10
9. Mikulowski P, Wollheim FA, Rotmil P: Sudden death in rheumatoid arthritis with atlanto-axial dislocation. Acta Med Scand Med Scand 1975 Dec; 1975 Dec; 198(6): 445-51