**7. Indications for surgical intervention**

A common question posed at both rheumatology and spine conferences is whether rheumatoid disease of the cervical spine is a surgical entity or not. Most clinicians would agree that the answer to this lies in the precise neurological and radiological findings at time of presentation. The three principal agreed indications for surgical intervention in rheumatoid patients are spinal cord compression, debilitating pain, or significant dislocation on radiology imaging (King 1985, Bland 1990, Bouchaud & Liote 2002).

Spinal cord compression may be noted on either clinical or radiological examination as detailed previously in this chapter. It is indisputable that spinal cord compression visible on radiological examination, in a patient medically fit for anaesthesia and not bedbound, mandates urgent spinal cord decompression and arthrodesis in the presence of neurological deficit. Indeed some authors have stated that such spinal cord compression in patients with neurological deficits is the only indication for surgical decompression (Pellicci et al 1981).

Intractable pain secondary to compression of the greater occipital nerve or the exiting two most cranial nerve roots, or perhaps true neck pain caused by irritation and strain of the synovial joint capsules and joint ligaments, can become debilitating despite maximal medical management (Pellicci et al 1981). Decompression, stabilisation and fusion of the cervical spine is indicated in this group of patients also. We do, however, advise a thorough assessment by a pain specialist and psychologist before embarking on surgical intervention in such cases (Borghouts et al 1998, Edwards et al 2006).

The last, and in our view the most difficult group to gain universal agreement on, are those rheumatoid patients without significant signs or symptoms, but who do display significant subluxation on radiology imaging. Some authors have noted spontaneous radiological fusion occurring on serial follow up, but a significant proportion of these "auto-fused" patients will progress to displaying neurological deterioration. Though the timing of, and indications for, surgical intervention in such individuals remain controversial, many authors advocate decompression and arthrodesis, on the basis that the degree of neurological compromise often does not correlate with the degree of radiological subluxation (Rana et al 1973, Bland 1990, Oostveen et al 1999). Further, arthrodesis with the appropriate technique has been shown to prevent progression, particularly in relation to C1/C2 subluxation

Posterior dislocation is found in less than 10% of cases of confirmed rheumatoid atlantoaxial dislocation (Lipson 1985). Destruction of the odontoid peg through a combination of previously described biomechanical and enzymatic means, results in the atlas subluxing posteriorly on the axis. The incidence of neurological deficit is very high due to the end position of the posterior arch of the atlas becoming wedged anterior to the spinous process

Rotatory dislocation is a less studied entity in the setting of rheumatoid disease. It is thought to occur in the setting of unilateral atlantoaxial joint destruction coinciding with severe

It is rare when assessing a rheumatoid patient to find that the anatomical abnormality can be neatly pigeon-holed into one of the described entities. Far more commonly, patients will have subluxed in a number of axes and directions, a concept of importance when considering instrumenting such cases. As a rough rule of thumb, anterior atlantoaxial dislocation occurs first, followed by cranial settling, before subluxation of C3-C7 occurs in

A common question posed at both rheumatology and spine conferences is whether rheumatoid disease of the cervical spine is a surgical entity or not. Most clinicians would agree that the answer to this lies in the precise neurological and radiological findings at time of presentation. The three principal agreed indications for surgical intervention in rheumatoid patients are spinal cord compression, debilitating pain, or significant dislocation

Spinal cord compression may be noted on either clinical or radiological examination as detailed previously in this chapter. It is indisputable that spinal cord compression visible on radiological examination, in a patient medically fit for anaesthesia and not bedbound, mandates urgent spinal cord decompression and arthrodesis in the presence of neurological deficit. Indeed some authors have stated that such spinal cord compression in patients with neurological deficits is the only indication for surgical decompression (Pellicci et al 1981). Intractable pain secondary to compression of the greater occipital nerve or the exiting two most cranial nerve roots, or perhaps true neck pain caused by irritation and strain of the synovial joint capsules and joint ligaments, can become debilitating despite maximal medical management (Pellicci et al 1981). Decompression, stabilisation and fusion of the cervical spine is indicated in this group of patients also. We do, however, advise a thorough assessment by a pain specialist and psychologist before embarking on surgical intervention

The last, and in our view the most difficult group to gain universal agreement on, are those rheumatoid patients without significant signs or symptoms, but who do display significant subluxation on radiology imaging. Some authors have noted spontaneous radiological fusion occurring on serial follow up, but a significant proportion of these "auto-fused" patients will progress to displaying neurological deterioration. Though the timing of, and indications for, surgical intervention in such individuals remain controversial, many authors advocate decompression and arthrodesis, on the basis that the degree of neurological compromise often does not correlate with the degree of radiological subluxation (Rana et al 1973, Bland 1990, Oostveen et al 1999). Further, arthrodesis with the appropriate technique has been shown to prevent progression, particularly in relation to C1/C2 subluxation

transverse ligament laxity or destruction (Bouchaud & Liote. 2002).

on radiology imaging (King 1985, Bland 1990, Bouchaud & Liote 2002).

in such cases (Borghouts et al 1998, Edwards et al 2006).

advanced cases (Paimela et al 1997).

**7. Indications for surgical intervention** 

of C2.

progressing to basilar invagination. Early intervention in these cases may obviate the need for later trans-oral decompression, a much more invasive procedure (Crockard et al 1986). Each case needs individual consideration both of the risks associated with surgical intervention, and also with the substantial risk of neurological compromise and mortality associated with conservative non-operative management (Sunchara et al 1997). Our practice advocates aggressive surgical management of such cases, in the belief that delaying intervention only places patients with impending neurological deficits at an unacceptably high risk of neurological compromise (Matsunaga et al 1976, Pellicci et al 1981, Casey et al 1996), whilst the patient's overall medical condition and mobility deteriorates, thereby raising the risk of inevitable surgical intervention.

Identification of asymptomatic patients likely to progress to neurological deterioration without arthrodesis relies on the experienced spine surgeon liaising with his rheumatology colleagues, and facilitating quick decompression and stabilisation should signs of early myelopathy become apparent. An atlantoaxial dental interval of greater than 10mm is certainly an indication for surgical intervention (Rana et al 1973), though intervals between the 5mm and 10mm need to be considered in the setting for the potential for progression to neurological dysfunction. Conventional trauma-based measurements cannot be extrapolated to rheumatoid patients, given that 5mm AADI is often seen in rheumatoid spines, as opposed to the 3mm limit of normal in unaffected adult individuals (Oda et al 1991, Shen et al 2004). We routinely favour the use of the posterior atlantodental interval as a more accurate screening mechanism for such patients, using a cut-off of 14mm as favoured by Boden et al, to stratify those at high risk of impending neural damage (Boden et al 1993). However, in our opinion, the overriding radiological measure is the presence of significant compromise on MRI imaging.
