Cervical spine instability in the course of rheumatoid arthritis – imaging methods

Abstract

Cervical spine is affected in more than a half of patients with rheumatoid arthritis (RA). Depending on the degree of damage to the individual joints and ligaments RA-related cervical spine instability takes the form of atlanto-axial subluxation, subaxial subluxation or cranial settling. In the advanced cases spinal stenosis can occur as well as spinal cord injuries with typical neurological symptoms. The identification of patients with cervical spine instability before the occurrence of neurological complications still constitutes a diagnostic challenge.The article presents the methods of cervical spine imaging with the use of plain radiographs, magnetic resonance imaging (MRI) and computed tomography (CT). We discuss the advantages and disadvantages associated with each method and the possibility of its application in the diagnosis of cervical spine instability in RA. The knowledge of the above mentioned issues is indispensable to select an appropriate time for surgical intervention.

Cervical Myelopathy in Patients Suffering from Rheumatoid Arthritis—A Case Series of 9 Patients and A Review of the Literature

“…By definition, an atlantoaxial subluxation is present if the atlantodental interval (AADI) measured on lateral radiographs is >3 mm. Evidence of AAS is also shown by a distance between the dens and C1 posterior arch (posterior atlantodental interval (PADI) <14 mm [7].…”

“…One popular diagnostic method is the Ranawat criteria, which is based on a line which connects the center of the anterior arch with the center of the posterior arch of C1 vertebra and a second line which is drawn along the axis of the odontoid process, from the center of the base of C2 vertebra to the intersection with the first line (Figure 1). The distance is used to assess the presence of the basilar invagination and based on the criterion are defined to be present when < 13 mm in women and < 15 mm in men [7]. Other diagnostic criteria of cranial settling are described in Figure 2.…”

“…Other diagnostic criteria of cranial settling are described in Figure 2. SAS is diagnosed when the radiograph in lateral projection shows horizontal displacement of vertebrae with irreducible translation by >3.5 mm (Table 1) [7].…”

“…The aim of the study was to evaluate variations in patient characteristics, surgical treatment and patient outcomes. To assess the cervical involvement and severity of myelopathy, the Ranawat classification (Table 3) and criteria and the modified Japanese orthopaedic association scale (mJOA); modified by Keller, 1993) were used to assess degree of neurological function [7,14]. Post-operative mJOA was obtained at the last follow-up, at least 3 months following operation.…”

“…Most common is an anterior atlantoaxial subluxation due to an affected anterior median atlanto-axial joint between ventral arch of C1 and the dens of the axis (circa 75% of all AAS). Subluxation in the posterior median atlanto-axial joint, located between posterior arch of C1 and the dens of the axis, as well as asymmetrical or unilateral changes of the lateral atlanto-axial joint leading to impairment in rotation are rare (7% and 20%) [7]. For diagnosis of cervical involvement in RA various diagnostic imaging options are available, each playing a different role depending on the stage of involvement (see discussion, Figures 1 and 2, Table 1).…”