Lumbar spine surgery in patients with rheumatoid arthritis (RA): what affects the outcomes?

Although the cervical spine is only occasionally involved in rheumatoid arthritis (RA), involvement of the lumbar spine is even less common. A few reports on lumbar spinal stenosis in patients with RA have appeared. Although disc space narrowing occurs in aging, postoperative adjacent segment disease (ASD) in patients with RA has not been subject to much analysis. The objective of this study was to investigate differences in ASD and clinical outcomes between lumbar spinal decompression with and without fusion in patients with RA. This is a retrospective comparative study. A total of 52 patients with RA who underwent surgery for lumbar spinal disorders were included. Twenty-seven patients underwent decompression surgery with fusion and 25 underwent decompression surgery alone. Intervertebral disc space narrowing and spondylolisthesis of the segment immediately cranial to the surgical site were measured using a three-dimensional volume rendering software. Pre- and postoperative evaluation of RA activity and Japanese Orthopaedic Association (JOA) scores were conducted. All patients had preoperative and annual postoperative lumbar radiographs and were followed up for a mean of 5.1 years (range 3.5–10.9 years). Pre- and postoperative (2 years after surgery) JOA scores were recorded and any postoperative complications were investigated. Degrees of intervertebral disc narrowing and spondylolisthesis at the adjacent levels were evaluated on radiographs and were compared between the two groups. Analysis was performed to look for any correlation between ASD and RA disease activities. Postoperative JOA scores were significantly improved in both groups. The rate of revision surgery was significantly higher in the fusion group than that in the non-fusion group. The rate of ASD was significantly greater in the fusion group than that in the non-fusion group at the final follow-up examination. Both matrix metalloproteinase 3 (MMP-3) and the 28-joint disease activity score incorporating C-reactive protein levels (DAS28-CRP) were significantly associated with the incidence and severity of ASD. Adjacent segment disease and the need for revision surgery were significantly higher in the fusion group than those in the non-fusion group. A preoperative high MMP-3 and DAS28-CRP are likely to be associated with postoperative ASD.