Abstract / Summary
Low back pain (LBP) is a leading cause of disability worldwide. Lumbar paraspinal muscle dysfunction is strongly associated with LBP, yet conservative treatments may not fully address underlying pathology. Non-surgical spinal decompression (NSSD) has emerged as a potential treatment option, though objective evidence supporting its effectiveness remains limited. Study Start: 1/1/2025, Study End: 12/31/2025. The objective of this study was to evaluate the longitudinal changes in paraspinal muscle morphology after NSSD treatment. Twenty-one participants (11 females, 10 males) with pre- and post-treatment MRIs treated at the USF Health Chiropractic Clinic, Department of Neurosurgery, Brain & Spine. Participants received NSSD using the DRX9000 ® targeting L4 ( n = 12) or L5 ( n = 9), with a median of 20 sessions (range: 19–26). The main outcome measures were Pain (0–10), Oswestry Disability Index (ODI, 0–50), and MRI-derived paraspinal muscle metrics obtained using the MuscleMap Toolbox . Associations between MRI metrics and patient-reported outcomes were assessed using Spearman correlations. Pain improved by 3.23 ± 1.51 points from a baseline of 5.43 ± 1.33 ( p < 0.001). ODI improved by 10.83 ± 8.86 points ( n = 12) from 15.22 ± 7.49 ( p = 0.001). No significant group-level changes were observed in MRI-derived muscle morphology following NSSD. In females, ΔODI was strongly correlated with ΔPain (ρ = 0.79, p = 0.019). Across all participants, there were no correlations between ΔODI or ΔPain with muscle cross-sectional area. Female-only analyses revealed significant associations between improvements in patient-reported outcomes and reductions in intramuscular fat in the erector spinae, multifidus, and quadratus lumborum. Pain and disability improved following NSSD treatment but there were no group-level changes in paraspinal muscle morphology. However, female participants who experienced greater functional improvement demonstrated reductions in intramuscular fat, suggesting potential sex-specific muscle-quality adaptations that may serve as markers of treatment responsiveness.