Article

Paraspinal muscle asymmetry in cross-sectional area (CSA) and
composition have been associated with low back pain and pathology. However,
substantial multifidus muscle asymmetry also has been reported in men who were
asymptomatic, and little is known about other factors influencing asymmetry.
OBJECTIVE: The goal of this study was to identify behavioral, environmental, and
constitutional factors associated with paraspinal muscle asymmetry. DESIGN: A
cross-sectional study of 202 adult male twins was conducted. METHODS: Data were
collected through a structured interview, physical examination, and magnetic
resonance imaging. Measurements of multifidus and erector spinae muscle CSA and
the ratio of fat-free CSA to total CSA were obtained from T2-weighted axial
images at L3-L4 and L5-S1. RESULTS: In multivariable analyses, greater asymmetry
in multifidus CSA at L3-L4 was associated with lower occupational physical
demands and less disk height narrowing. Handedness was the only factor associated
with multifidus muscle CSA asymmetry at L5-S1. For the erector spinae muscle,
greater age, handedness, and disk height narrowing were associated with CSA
asymmetry at L3-L4, and sports activity, handedness, disk height narrowing, and
familial aggregation were associated with CSA asymmetry at L5-S1. In
multivariable analyses of asymmetry in muscle composition, familial aggregation
explained 7% to 20% of the variance in multifidus and erector spinae muscle
side-to-side differences at both levels measured. In addition, handedness and
pain severity entered the model for erector spinae muscle asymmetry at L5-S1, and
disability, handedness, and disk height narrowing entered the model for
multifidus muscle asymmetry at L5-S1. LIMITATIONS: Reliance on participants'
recall for low back pain history, occupation, and physical activity levels was a
limitation of this study. CONCLUSIONS: Few of the factors investigated were
associated with paraspinal muscle asymmetry, and associations were inconsistent
and modest, explaining little of the variance in paraspinal muscle asymmetry.

Langue : ANGLAIS