Surgical Considerations of Rheumatoid Disease Involving the Craniocervical Junction and Atlantoaxial Vertebrae

Rheumatoid arthritis is a progressive systemic erosive inflammatory polyarthropathy causing symptoms both as a result of disease progression, (Zikow et al 2005, Gorter et al 2010, Klarenbeek at al 2010), and as result of medical management of the disease process itself (Haugeberg et al 2003). It affects synovial joints in 1% of the world’s population (Matteson 2003) , with more than 50% of those affected experiencing involvement of the cervical spine (Cabot & Becker 1978, Yurube et al 2011, GarciaArias et al 2011) It is characterised by an erosive synovitis, causing destruction of the articular joint surfaces, joint capsules and supporting ligaments for the joints. The atlantoaxial joint is the most commonly affected (Dreyer et al 1999). Though the disease process can cause horrendous morphological change to the cervical joints, with concomitant changes to joint function and stability, neurological dysfunction is surprisingly uncommon. The importance of regular neurological assessment and rapid intervention lie in the rapid progression to disability with the onset of neurological deficits (Rana 1989), allied with a significantly increased mortality rate (Mikulowski et al 1975, Paus et al 2008). Great strides in the development and evolution of spine surgery techniques and instrumentation have been made treating individuals with cervical and craniocervical junction dysfunction. The complexities encountered when approaching the craniocervical junction of a severe rheumatoid neck, and the anatomical variability of the neural and vascular structures that may be iatrogenically breached (Bruneau 2006) mandate the use of image guidance techniques and/or conductivity detection devices (Kelleher et al 2006) to limit intraoperative risk (Kotani et al 2003, Aryon et al 2008). The vertebrae of the region most commonly affected by rheumatoid degenerative disease, namely the craniocervical junction and the atlantoaxial joints, have a very complex anatomical relationship with traversing nerves, vessels, and of course the spinal cord (Oliveira et al 1985), and an appreciation of the structure and function of the components of these joints (including how degenerative changes alter the kinematics and structural integrity) is integral to safe surgery in the region. The most common causes for surgical review of the cervical spine of rheumatoid patients include basilar invagination, atlantoaxial instability and subaxial subluxation (Boden et al 1993). Despite an improvement in spine surgical techniques and technology, rheumatoid