Abstract and Introduction
Study Design. Retrospective data analysis.
Objective. To compare the trends in primary cervical spine fusion procedures in patients with rheumatoid arthritis (RA) against those in the general population.
Summary of Background Data. RA severely impacts multiple joints in the body and can result in substantial deformity and functional impairment. Cervical spine involvement is common. In the past decade, treatment for RA has changed substantially with the introduction of biologically based, disease-modifying antirheumatic medications. Recent literature has shown decreasing rates of total joint arthroplasty in patients with RA.
Methods. Cases of cervical spine fusion in the general population and in patients with RA were identified from the Nationwide Inpatient Sample from 1992 through 2008. US population counts were obtained from the Census Bureau. Data were analyzed with computer software (significance, P < 0.05 for all analyses). Linear regression models were used to describe national rates of cervical spine fusion in patients with and without RA.
Results. There was a marked increase in the number of cervical fusion procedures in the studied population. Over time, the incidence of atlantoaxial fusion increased in the general population (P < 0.01) and decreased in patients with RA (P < 0.01). Compared with the general population, patients with RA had a significantly lower rate of increase in the incidence of posterior cervical fusion (P < 0.01) and a significantly higher rate of increase in the incidence of anterior cervical fusion (P < 0.01).
Conclusion. In the US, the absolute number of primary cervical fusion procedures from 1992 through 2008 increased in the general population and in patients with RA. However, the patients with RA had a significantly lower incidence of undergoing atlantoaxial and posterior cervical surgical procedures than did the general population.
Level of Evidence: 2
Rheumatoid arthritis (RA) is a chronic, inflammatory disease associated with damage to the articular cartilage and periarticular bone. It has a worldwide prevalence of approximately 1% and affects approximately 1.3 million adults in the US. Because it can severely impact multiple joints in the body, RA can result in substantial deformity and functional impairment. Involvement of the cervical spine is common. In the literature, prevalence rates range from 17% to 80%.[2–5] Manifestations of RA in the cervical spine can range from atlantoaxial subluxation, cranial settling, and subaxial subluxation, to a combination of these deformities.[2–5] Of these conditions, atlantoaxial subluxation has the most substantial disease burden, given its widespread presence in patients with RA and its associated morbidity. Early referral and novel medical interventions have led to substantial improvement in the long-term outcomes of patients with RA.[6,7] In the past decade, the treatment of RA has changed substantially with the introduction of biologically based disease-modifying antirheumatic medications (DMARDs). These agents modulate the inflammatory environment associated with RA and aim to slow disease progression and preserve function. Recent combination therapies involving these newer agents, such as tumor necrosis factor [alpha], and traditional DMARDs, such as methotrexate, have led to substantial improvements in disease management.[8,9] Nevertheless, a large number of patients with RA necessitate spinal surgical intervention.[10,11]
There has been an increased focus in the literature on declining rates of joint arthroplasty in the RA population. National registries from Sweden,[12,13] Denmark, Norway, and the US have reported that the number of extremity total joint arthroplasties in patients with RA has decreased during the last decade, suggesting that the long-term clinical outcome of such patients has been improving. These trends have largely been attributed to the use of effective DMARDs and biological agents.Using data from the US Nationwide Inpatient Sample (NIS) database from 1992 through 2008, we sought to compare the trends in primary cervical spine fusion procedures in patients with RA against those in the general population. We hypothesized that similar changes in disease progression have taken place in the cervical spine with a decrease in the relative rate of fusion procedures in patients with RA compared with the rest of the population.