Relationship between performance on lumbar dynamometry and Waddell score in a population with low-back pain

Area of Science:

• Biomedical Engineering
• Rehabilitation Medicine
• Psychology

Background:

• Low-back pain is a prevalent condition often assessed using biomechanical testing.
• The influence of psychological factors and illness behavior on these assessments is not fully understood.

Purpose of the Study:

• To investigate the relationship between biomechanical variables during lumbar dynamometry and psychological measures in patients with chronic low-back pain.
• To determine if nonorganic pain behavior influences objective functional assessments.

Main Methods:

• Prospective, blinded cohort study of 85 men with low-back pain (>5 weeks duration).
• Lumbar function assessed using the Isostation B-200 Lumbar Dynamometer.
• Nonorganic pain behavior measured by Waddell score; psychological status by Coopersmith Self-Esteem inventory and wellness self-rating.

Main Results:

• Patients with excessive illness behavior (Waddell Scores 3-5) showed significantly worse performance on most biomechanical variables (P < .01).
• Self-reported self-esteem and wellness scores correlated significantly, though weaker, with motor performance.
• Statistical analysis included t-tests, Pearson r correlation, ANOVA, and multiple stepwise logistic regression.

Conclusions:

• Poor performance on biomechanical testing in this cohort may represent abnormal illness behavior.
• Biomechanical test results might not accurately reflect underlying organic neuromusculoskeletal dysfunction in individuals exhibiting nonorganic pain behaviors.