Abstract / Summary
Abstract Objectives Restricted sliding at lumbar myofascial interfaces may contribute to chronic low back pain with myofascial pain features (CLBP-MP). We aimed to evaluate magnetic resonance elastography (MRE)-based slip interface imaging (SII) to quantify lumbar intermuscular myofascial mobility in healthy volunteers (HV), assessing repeatability, and comparing CLBP-MP patients with matched HV. Materials and methods MRE/SII was performed in 20 CLBP-MP patients and 41 HV. SII-derived maximal normalized displacement discontinuity (Dnorm) was analyzed at the quadratus lumborum–erector spinae (QL–ES) and ES–multifidus (ES–M) interfaces at L3–L4, computing mobility indices. Repeatability was assessed via within-subject coefficient of variation (wCV) and Bland–Altman analysis. In HV, associations with age/sex/body mass index (BMI) were tested. Group differences were evaluated by comparing patients with matched HV and by stratifying patients by “pain, enjoyment, and general activity” (PEG) score using one-way ANOVA. Associations with PEG were evaluated using Pearson correlation. Results Repeatability was excellent (mean wCV < 10% for within- and between-day). In HV, myofascial mobility differed by anatomic interface and vertebral level but showed no association with age, sex, or BMI. At L4 ES–M, mobility showed a significant group effect (F(2,37) = 13.23, p < 0.001), with lower mobility in moderate-to-severe versus mild pain ( q = 0.023) and versus HV ( q < 0.001), and correlated negatively with PEG ( r = −0.51, p = 0.021). Conclusion Pain-related reductions in localized lumbar intermuscular myofascial mobility in CLBP-MP were shown. MRE-based SII is a repeatable quantitative technique, supporting its potential as an early-stage biomarker for characterizing lumbar myofascial mobility and guiding multicenter studies. Key Points Question Lumbar myofascial interface sliding is essential for normal movement, but objective quantification of sliding dysfunction in chronic low back pain remains limited. Findings SII showed high repeatability and reduced L4 erector spinae-multifidus mobility associated with greater pain severity in chronic low back pain patients. Relevance statement MR elastography-based SII offers repeatable, noninvasive measurement of lumbar myofascial mobility and shows pain-related localized restriction in chronic low back pain with myofascial features, supporting objective characterization of inter-muscular myofascial mechanics and exploratory biomarker development.