Predictors of clinical success with stabilization exercise are associated with lower levels of lumbar multifidus intramuscular adipose tissue in patients with low back pain.

Purpose: Investigate the construct validity of prognostic factors purported to predict clinical success with stabilization exercise for low back pain by exploring their associations with lumbar multifidus composition. Methods: Patients with low back pain were recruited from a hospital imaging department. The presence of fivepredictors (age <40 years, positive prone instability test, aberrant trunk flexion movements, straight leg raise range of motion >91°, spinal hypermobility) were identified by standardized physical examination. Predictors were grouped by total positive findings and status on a clinical prediction rule. The proportion of lower lumbar multifidus intramuscular adipose tissue was measured with 3.0 T magnetic resonance imaging. Univariate and multivariate associations were examined with linear regression and reported with standardized beta coefficients (β) and 95% confidence intervals. Results: Data from 62 patients (11 female) with mean (SD) age of 45.2 (11.8) years were included. Total number of predictors (β[95% CI] = -0.37[-0.61,-0.12]; R2  = 0.12), positive prediction rule status (β[95% CI] = -0.57[-0.79,-0.35]; R2  = 0.30), and age <40 years were associated with lower intramuscular adipose tissue (β[95% CI] = -0.55[-0.77,-0.33]; R2  = 0.27). No other individual factors were associated with lumbar multifidus intramuscular adipose tissue. Conclusions: These findings support the construct validity of the grouped prognostic criteria. Future research should examine the clinical utility of these criteria. Implications for RehabilitationLow back pain is the single largest cause of disability worldwide and exercise therapy is recommended by international low back pain treatment guidelines.Lower levels of lumbar multifidus intramuscular adipose tissue were associated with predictors of clinical success with stabilization exercise.Higher proportions of lumbar multifidus intramuscular adipose tissue may help identify patients who require longer duration exercise training, or those who are unlikely to respond to stabilization exercise.