A randomized clinical trial of treatment for lumbar segmental rigidity

Abstract

Study design: A randomized single-blind clinical trial of facet injections plus exercise, versus exercise alone, in chronic disabling work-related lumbar spinal disorders (CDWRLSD), accompanied by pilot interrater reliability and facet syndrome prevalence studies.

Objectives: To systematically investigate the use of facet injections as an adjunct to supervised lumbar stretching exercises in regaining lumbar range of motion (ROM) following prolonged deconditioning after work-related lumbar injuries. To assess interrater reliability of visual assessment of segmental rigidity (SR), and to evaluate the prevalence of facet syndrome in cases of lumbar SR.

Summary of background data: Corticosteroid joint injections have often been used to reduce musculoskeletal inflammation to facilitate joint mobilization in the presence of degenerative arthritis. Lumbar segmental rigidity is a recently described entity usually associated with painful chronic spinal disorders and postoperative spine surgery. Previous work has shown that SR and lumbar ROM improves with a brief intervention consisting of facet injections followed by specific stretching exercises. No systematic study has investigated the potential benefits of a combination of facet injections and exercise over supervised exercises alone to treat lumbar SR. Similarly, no study has assessed the association between SR and the facet syndrome.

Methods: From a group of consecutive patients (n = 421) with CDWRLSD referred for tertiary rehabilitation between November 1999 and January 2001, 70 were noted to have SR on intake physical examination. The first part of this study assessed interrater reliability for detecting SR, and intrarater reliability for 3-segment true lumbar ROM measurements. Patients randomly assigned to participate in supervised stretching exercises with the addition of fluoroscopically guided bilateral facet injections at the involved levels (Group A, n = 36) also underwent facet syndrome prevalence assessment at the time of injection. They were compared to a randomly allocated comparison group (Group B, n = 34) undergoing exercises alone in a single-blind design. Physical therapists saw patients an average of twice per week, providing supervision of a progressive home stretching program. Inclinometric joint ROM was measured at the time of group allocation, and again 5 to 7 weeks later. Validated questionnaires of pain (intensity VAS) and disability (Million VAS) related to the CDWRLSD were provided before and after the interventions.

Results: Part 1 reliability and facet syndrome prevalence work revealed that interrater reliability for experienced examiners to detect rigid segments was excellent (Pearson's r = 0.97, P < 0.01). Intrarater 3-joint motion measurement reliability was also good for all sagittal/coronal ROM (Pearson's r = 0.95-0.99, P < 0.01). Only 5 of 29 subjects with SR met criteria for facet syndrome (17%), consistent with prior prevalence studies of unselected patients with low back pain. In Part 2, a large majority of patients in both groups improved from the initial to the post-treatment ROM measurements (the primary outcome criterion of the study). However, a higher proportion of Group A (injection) patients (87%-95%) showed ROM improvement, compared to Group B (exercise only) patients (64%-79%). Group A patients showed a significantly greater ROM improvement in all sagittal and coronal movements, both in absolute terms and percent of initial measurement. No significant differences in pain or disability self-report were found between groups, pre- or postintervention, but both groups showed significant improvement from pre- to postintervention in pain and disability assessments.

Conclusions: The detection of SR and measurement of 3-segment true lumbar ROM by experienced examiners is highly reliable. Only 17% of CDWRLSD patients with lumbar SR met criteria for the facet syndrome, a rate approximately equal to that of unselected low back pain cohorts. This indicates that lumbar SR may be found whether or not pain of facet joint origin is present. In the randomized trial, facet injections significantly increased the percentage of patients with SR showing ROM improvement, as well as the degree of improvement in lumbar mobility after treatment. There is no evidence that facet injections increase the improvements in pain/disability report noted in both groups.