Background/Purpose:

Formation of pannus, an inflammatory tissue mass, in the atlanto-axial joint of the cervical spine is an important sequela of rheumatoid arthritis (RA). Atlanto-axial pannus may result in spinal cord injury if not recognized in a timely manner. The purpose of this study was to further characterize patients with RA and atlanto-axial pannus in order to more accurately identify these patients in clinical practice.

Methods:

Subjects were identified by free text searching the Partners HealthCare Research Patient Data Registry for the terms ‘atlanto-axial’ and ‘pannus’ in cervical spine magnetic resonance imaging (MRI) reports between January 1, 2001 and December 31, 2015. RA diagnoses were verified by chart review conducted by 2 reviewers. Data were extracted regarding demographics, prior cervical spine surgery, years since RA diagnosis, clinical presentation, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, presence of rheumatoid factor or anti-cyclic citrullinated peptide (CCP) antibody, and surgery or medication change after MRI demonstrating pannus.

Results:

Seventy-four patients were identified with pannus in the atlanto-axial joint, and 27 of these patients had a confirmed diagnosis of RA, including 5 with juvenile rheumatoid arthritis (JRA). At the time of MRI, the mean age of patients with pannus and RA was 58 years. The median number of years since RA diagnosis was 21 years (range 5-69 years). Most patients were female (85%) and white (78%). Fifteen percent of patients had undergone cervical spine surgery prior to the identification of atlanto-axial pannus. The most common specialty to provide referral for cervical spine MRI was rheumatology (59%). The vast majority of patients reported neck pain (85%), and only 11% reported associated traumatic injury. Only 41% had an abnormal neurologic exam, most commonly an abnormal sensory exam (15%). Eighty-one percent of patients had ESR or CRP checked within 3 months of MRI (mean ESR 39 ± 33 millimeters per hour, median CRP 6.4 milligrams per liter (interquartile range 13.0)). Sixty-seven percent of patients were seropositive, and 67% had been treated with biologic therapy prior to MRI. Only 15% of patients underwent cervical spine surgery after MRI, but all of these patients reported improvement in their symptoms post-operatively. The majority of patients had no change in their RA medications after MRI demonstrating pannus (81%).

Conclusion:

The majority of patients with atlanto-axial pannus had long-standing RA, but pannus was also reported as soon as 5 years after RA diagnosis. Atraumatic neck pain in a patient with RA should prompt consideration of atlanto-axial pannus, and clinicians should not be dissuaded by a normal neurologic exam. Interestingly, the proportion of patients with seronegative RA and pannus formation in our study was similar to the frequency of seronegative disease in the general RA population. Most of the patients in our study were diagnosed in the pre-biologics era. It needs to be shown whether treatment of RA with biologics will result in a lower incidence of atlanto-axial pannus in the future.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/characteristics-of-patients-with-rheumatoid-arthritis-and-atlanto-axial-pannus/