Predicting Chronic Low Back Pain
Psychological factors have been shown to be predictors of chronic disability, but measures from physical examination rarely predict 
chronic behavior. The centralization phenomenon (CP) is a pain pattern response that may occur when patients are asked to move is specific directions, such as in the McKenzie method.
The CP demonstrates a favorable change when pain moves from a distal or peripheral location to a proximal or central one during the specific movements. The authors of this study investigated whether the CP had any ability to predict chronic pain behavior in patients with low back pain (LBP).
Two hundred twenty-three consecutive adults with acute LBP with or without referred spinal symptoms were treated conservatively and followed prospectively for one year. Patients with acute symptoms and no history of surgery were treated by five physical therapists trained in McKenzie evaluation and treatment methods. Seventy-three percent of the subjects were receiving workers� compensation benefits. At initial evaluation and discharge, 23 patient factors were assessed representing psychosocial, clinical, and demographic factors. Pain location changes to repeated trunk movements were assessed at every visit.
Patients were placed into two groups, those with pain that did not centralize, and those who completely centralized or demonstrated partial reduction of pain location with time. Treatment was individualized and based on McKenzie methods. Patients were contacted at twelve months after discharge, and dependant variables of pain intensity, return to work status, sick leave at work, activity interference at home, and continuous use of health care were assessed.
Results showed that nine independent variables influenced pain symptoms or disability. Pain pattern classification (non-centralization) and leg pain at intake were the strongest predictive variables of time related measures.
Conclusion: Dynamic assessment of change in anatomic pain location during treatment and leg pain at intake were predictors of developing chronic pain and disability. The authors point out that because the tests possessed low sensitivity, the strength of the test should be interpreted cautiously.
Back Pain Treatment at BANAS SPORTS THERAPY
Werneke M, Hart DL. Centralization phenomenon as a prognostic factor for chronic low back pain and disability. Spine 2001:26(7), pp. 758-765.
