Poster - #VH-14549 - Keywords: low back pain paraspinal muscles lumbar spine physical function disability

The Association Between Lumbar Paraspinal Muscle Morphology and Physical Function, Disability, and Pain in Adults with Chronic Low Back Pain

Cristiane R. Carlesso, PT, PhD; Jacklyn M. Sions, DPT, PhD; Charity G. Patterson, PhD, MSPH; William J. Anderst, PhD; Michael J. Schneider, DC, PhD; Luiza P. Weissmann, Allison M. Voss; Blake S. Johnson; Sara R. Piva, PT, PhD
Department of Physical Therapy, University of Pittsburgh. Department of Physical Therapy, University of Delaware. Department of Orthopedic Surgery, University of Pittsburgh. Department of Community Health Services and Rehabilitation Science, University of Pittsburgh. Swanson School of Engineering, University of Pittsburgh. 6. School of Health and Rehabilitation, University of Pittsburgh

ABSTRACT:
Introduction: Chronic low back pain (cLBP) is often associated with atrophy and increased fat infiltration of the lumbar paraspinal muscles (LPM), compromising spinal control and stability during movement, which may affect physical function, disability, and pain. The aim of this study was to explore the relationship between LPM characteristics and physical function, disability, and pain in adults with cLBP.

Methods: This cross-sectional study used data from a prospective observational study in cLBP. Physical function was assessed through performance-based tests, including the 5-Time Sit-to-Stand Test (5TSTST), 4-Meter Walk Test (4MWT), Active Sit-Up Test (ASUT; ≤10s, >10s), and Single-leg Stance Test (SLST; ≤60s, >60s). Disability was measured using the Oswestry Disability Index (ODI). Low back pain intensity and neuropathic pain were assessed using the Numerical Pain Rating Scale (NPRS) and the PainDETECT (PD) questionnaire. Computed tomography (CT) images were used to analyze the cross-sectional area (CSA) and attenuation of the LPMs, including the erector spinae and multifidi at the upper (L1-L3) and lower (L4-S1) lumbar segments, as well as the quadratus lumborum and psoas at L3, using Mimics software. Linear and logistic regression models, unadjusted and adjusted for age, sex, and Body Mass Index, were used to examine the associations.

Results: A total of 193 participants were analyzed (Average age: 55±16 years, BMI: 27.2±4.0 kg/m², 55% female, and mean ODI: 25.5±11.7). For muscle CSA, unadjusted models revealed associations between the upper and lower erector spinae, as well as the quadratus lumborum, with the SLST; the lower erector spinae with the 4MWT; the lower erector spinae and psoas with the ASUT; and the lower multifidus with PD. After adjustments, associations remained between lower erector spinae and 4MWT (β: .00004, R2: .103), lower multifidi and PD (β: -.007, R2: .031), quadratus lumborum and ASUP (β: -.004, pseudo R2: .325), and upper erector spinae and SLST (β: .002, pseudo R2: .368). For muscle attenuation, unadjusted models demonstrated associations between all LPMs and the 4MWT, SLST, and ASUP, as well as between the upper and lower erector spinae, lower multifidi, and quadratus lumborum with the 5TSTST, and the lower erector spinae with the ODI. After adjustments, the upper erector spinae remained associated with the ASUP (β: .046, pseudo R2: .306) and the quadratus lumborum with the SLST (β: .046, pseudo R2: .355).

Conclusions: Findings linking LPM characteristics to physical function and neuropathic pain in cLBP support further research on these relationships longitudinally and within demographic subgroups.