The relationship between nonorganic signs and centralization of symptoms in the prediction of return to work for patients with low back pain

Abstract

Background and purpose: The purpose of this study was to assess the relationship between the nonorganic signs (Waddell scores) of patients with low back pain, their response to repetitive end-range lumbar spine test movements (centralization of symptoms), and the rate of return to work at a 6-month follow-up.

Subjects: Patients were assessed at five locations of the Canadian Back Institute. A consecutive sample of 126 patients with low back pain, with or without referred leg pain, was selected and reviewed.

Methods: Physical therapists assessed patients' responses to repetitive test movements (centralization), as described by McKenzie, and tested the patients for nonorganic signs (Waddell scores). Therapists completed a data sheet that classified patients as either those who centralize their symptoms or those who do not centralize their symptoms and recorded their Waddell scores. Although the patients were classified at assessment, they remained in treatment. All patients followed a structured Canadian Back Institute protocol of active exercise, regardless of centralization status or Waddell score.

Results: The inability to centralize symptoms indicated a decreased likelihood of returning to work, regardless of the Waddell score. A high Waddell score predicted a poor chance of returning to work, regardless of the patients' ability to centralize symptoms.

Conclusion and discussion: A high Waddell score appears to be the best predictor of outcome, as indicated by return to work.