Multifidus Muscles Lipid Content Is Associated with Intervertebral Disc Degeneration: A Quantitative Magnetic Resonance Imaging Study

STUDY DESIGN: Cross-sectional study. PURPOSE: To determine the association between fatty degeneration of the multifidus muscle (Mm) and intervertebral disc degeneration (IVDD) using quantitative magnetic resonance imaging (MRI). OVERVIEW OF LITERATURE: Few studies have reported on quantitative MRI analysis of the relation between the Mm and IVDD. METHODS: The subjects with chronic low back pain comprised 45 patients (19 males, 26 females; mean age, 63.8±2.0 years; range, 41–79 years). We analyzed the intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) of the Mm using magnetic resonance spectroscopy. The T2 values of the anterior annulus fibrosus (AF), nucleus pulposus (NP), and posterior AF were evaluated using MRI T2 mapping. We compared the possible correlations of IMCL and EMCL of the Mm with the T2 values of anterior AF, NP, and posterior AF. RESULTS: There was a significant negative correlation between IMCL and T2 values of the anterior AF (r=−0.65, p<0.01). There were no significant correlations between the IMCL and T2 values of NP (r=−0.16, p=0.30) and posterior AF (r=0.07, p=0.62). There were no significant correlations between the EMCL and T2 values of the anterior AF (r=−0.11, p=0.46), NP (r=0.15, p=0.32), and posterior AF (r=0.07, p=0.66). After adjustment for age and sex using multiple linear regression analysis, there was a significant negative correlation between the IMCL and T2 values of anterior AF (standardized partial regression coefficient=−0.65, p<0.01). CONCLUSIONS: The results indicated that IMCL of the Mm might be accompanied with anterior AF degeneration. Therapeutic exercises using IMCL of the Mm as evaluation index might have the potential to identify novel targets for the treatment and prevention of IVDD.