DISABILITY, PAIN, PSYCHOLOGICAL FACTORS AND PHYSICAL PERFORMANCE IN HEALTHY CONTROLS, PATIENTS WITH SUB-ACUTE AND CHRONIC LOW BACK PAIN: A CASE-CONTROL STUDY
Jens Ivar Brox A1, Kjersti Storheim A2, Inger Holm A3, Astrid Friis A3, Olav Reikerås A1
A1 Department of Orthopaedic Surgery, Section for Back Surgery and Physical Medicine and Rehabilitation National Hospital Oslo
A2 Norwegian University of Sports and Physical Education Oslo
A3 Department of Physiotherapy National Hospital Oslo Norway
Objective: To compare measures of disability, psychological factors, pain and physical performance in healthy controls, and patients with sub-acute and chronic low back pain. To evaluate the concept of the deconditioning syndrome and to explore factors that may contribute to chronicity. Design: Case-control study. Subjects: Three age- and gender-matched groups were included in the study; healthy controls (n=45), patients sick-listed 8-12 weeks (n=46) and patients with chronic low back pain on a waiting list for lumbar instrumented fusion (n=45). Methods: Measures of disability, pain, psychological factors, and physical performance were obtained from the 3 groups using validated measures. Results: Gender, age, body weight and height were not significantly different between the groups. Comparable scores were found for self-rated working ability, fear-avoidance beliefs for physical activity and aerobic capacity in the 2 patient groups. Oswestry Disability Index, pain, emotional distress, abdominal and back muscle endurance were significantly different between the 3 groups. Self-efficacy for pain and fear-avoidance beliefs for work was significantly different between the 2 patient groups. Conclusion: The results suggest a stepwise deterioration of impairment and disability from healthy controls to patients with chronic low back pain. Most variables distinguished between healthy controls and patients with sub-acute or chronic low back pain. Deconditioning was more related to psychophysical measures of abdominal and back muscle endurance than to cardiovascular fitness. Comparable scores for fear-avoidance and working ability in the 2 patient categories suggest that these factors appear at an early stage and contribute to the transition from acute to chronic low back pain.