UPPER AND LOWER CUTOFF LIMITS FOR STATIC AND DYNAMIC LUMBAR MOTION IN NON-SPECIFIC CHRONIC LOW BACK PAIN

Purpose and Background: To compare static and dynamic lumbar intervertebral ranges of motion (IV-RoM) in patients with chronic, nonspecific low back pain with upper and lower cut off values derived from healthy controls when variability and measurement errors were reduced. Measurements from functional radiographs suffer from high variability and measurement errors, making cut off values for excessive or insufficient motion problematical. This study compared maximum lumbar IV-RoM and maximum IV-RoM at any point in continuous motion sequences in patients with chronic, non-specific back pain with upper and lower cut off values for L2 to L5 from matched controls using quantitative fluoroscopy, where variation and measurement errors were reduced. Methods and Results: Participants underwent passive recumbent examinations in the sagittal and coronal planes. Values based on were developed for both maximum and continuous motion in controls (n=40). Fishers exact test was used to analyse proportions of patients whose IV-RoMs exceeded reference values. For maximum IV-RoM in patients, there were no statistically significant differences between groups for the lower value. Only flexion at L4/5 significantly exceeded the upper value (p=0.03). For continuous IV-RoM, left L3/4 (p=0.01) and right L4/5 (p=0.01) were significantly below the lower cut off values. Both flexion L4/5 (p=0.05) and left L3/4 (p=0.01) were significantly above the upper cut off values. Conclusions: Controlling variability and reducing errors allowed meaningful upper and lower cut off values to be produced for both static and dynamic IV-RoM and may lead to better treatment decisions for those with suspected inter-vertebral stiffness or hypermobility.