Fear-avoidance beliefs are associated with a high fat content in the erector spinae: a 1.5 tesla magnetic resonance imaging study.

Background: Intramuscular adipose tissue (IMAT) is a feature of degenerative muscle composition and is a common feature in populations with chronic low back pain (CLBP). Avoidance behavior is a possible cause of morphological muscle composition due to disuse of the paraspinal muscles. Therefore it is of clinical interest to determine the association between fear-avoidance beliefs and IMAT of the paraspinal muscles in populations with CLBP.

Methods: In this cross-sectional study, we examined twenty-four adults, featuring a mean age of 48.63 years (SD ± 14.73), with CLBP. Axial T2-weighted Magnetic Resonance Imaging (MRI) images were selected on the same level as the intervertebral disc of segments L4-L5 and L5-S1. After determine the region of interest, the amount of IMAT was measured by an automatic-threshold method to distinguish fat from muscle tissue. Fear-avoidance beliefs were measured with the Fear-Avoidance Beliefs Questionnaire, with regard to Physical Activity (FABQ-PA). Bivariate correlation and multiple regression analysis were used to determine the association between IMAT of the paraspinal muscles and fear-avoidance beliefs.

Results: There is a significant bivariate association between the FABQ-PA and ES IMAT ( = 0.484,  = 0.017), but not for LMM ( = 0.228,  = 0.284). The association between the FABQ-PA and ES IMAT remained moderate after adjusting for covariates (β = 0.381,  = 0.028).

Conclusion: Fear-avoidance beliefs are moderately associated with ES IMAT and poorly associated with LMM IMAT in a population with CLBP. Results should be interpreted with caution due to a small and selected study population.