Understanding the Interplay Between Paraspinal Muscle Atrophy and Lumbar Endplate Degeneration

Abstract

Study Design. Retrospective analysis of longitudinal data. Objective. To assess the association between the paraspinal musculature (PM) and lumbar endplate degeneration. Background. The PM is essential for spinal stability, while the vertebral endplate is pivotal for nutrient transport and force distribution. The clinical importance of both has been highlighted in recent literature, though little is known about their interaction. Methods. We identified patients with lumbar MRI scans due to low back pain, with a 3-year interval between MRI scans. Endplate damage was assessed by the total endplate score (TEPS) at each lumbar level. The PM was evaluated for its functional cross-sectional area (fCSA) and fatty infiltration (FI) at the L4 level. We used a generalized mixed model to analyze the association between PM parameters and TEPS at timepoint one, adjusting for age, sex, BMI, diabetes, hypertension, and smoking status. The association with the progression of endplate damage was analyzed through an ordinal regression model, additionally adjusted for TEPS at baseline. Results. 329 patients were included, with a median follow-up time of 3.4 years. Participants had a median age of 59 and a BMI of 25.8 kg/m2. In the univariate analysis, FI of the posterior PM was significantly associated with TEPS at baseline (β: 0.08, P<0.001) and progression of TEPS (OR: 1.03, P=0.020) after adjustment for confounders. The β and OR in this analysis are per percent of FI. In a binary analysis, patients with FI ≥ 40% had an OR of 1.92 (P=0.006) for the progression of TEPS. Conclusions. This is the first longitudinal study assessing the relationship between PM and endplate degeneration, demonstrating the association between PM atrophy and progression of endplate degeneration. This insight may aid in identifying patients at risk for degenerative lumbar conditions and guide research into preventive measures.

Editorial for “Evaluation of the Reproducibility of MR Elastography Measurements of the Lumbar Back Muscles”

“…7 Moreover, a correlation between paraspinal muscle atrophy and the progression of vertebral endplate degeneration has been recently demonstrated. 8 Paraspinal muscles can be assessed by visual qualitative or semi-quantitative methods, assessing fatty infiltration and musculature thickness. Moreover, several quantitative tools (with dedicated software programs) applicable to MRI are available in order to provide an accurate and reliable assessment of this critical factor in degenerative spine disease.…”

“…In detail, lumbar stenosis has been linked to multifidus degeneration, which includes decreased volume, increased fatty infiltration, and bilateral muscle asymmetry 7 . Moreover, a correlation between paraspinal muscle atrophy and the progression of vertebral endplate degeneration has been recently demonstrated 8 . Paraspinal muscles can be assessed by visual qualitative or semi‐quantitative methods, assessing fatty infiltration and musculature thickness.…”