Background: A clinical prediction rule (CPR) purported to identify patients with neck pain who are likely to respond to thoracic spine thrust manipulation has recently been developed, but has yet to be validated.
Objective: The purpose of this study was to examine the validity of this CPR.
Design: This was a multi-center randomized clinical trial.
Methods: One hundred forty patients with a primary report of neck pain were randomly assigned to receive either 5 sessions of stretching and strengthening exercise (exercise-only group) or 2 sessions of thoracic spine manipulation and cervical range of motion exercise followed by 3 sessions of stretching and strengthening exercise (manipulation + exercise group). Data on disability and pain were collected at baseline, 1 week, 4 weeks, and 6 months. The primary aim (treatment group x time x status on the prediction rule) was examined using a linear mixed model with repeated measures. Time, treatment group, and status on the rule, as well as all possible 2-way and 3-way interactions, were modeled as fixed effects, with disability (and pain) as the dependent variable. Effect sizes were calculated for both pain and disability at each follow-up period.
Results: There was no 3-way interaction for either disability or pain. A 2-way (group x time) interaction existed for both disability and pain. Pair-wise comparisons of disability demonstrated that significant differences existed at each follow-up period between the manipulation + exercise group and the exercise-only group. The patients who received manipulation exhibited lower pain scores at the 1-week follow-up period. The effect sizes were moderate for disability at each follow-up period and were moderate for pain at the 1-week follow-up.
Limitations: Different exercise approaches may have resulted in a different outcome.
Conclusions: The results of the current study did not support the validity of the previously developed CPR. However, the results demonstrated that patients with mechanical neck pain who received thoracic spine manipulation and exercise exhibited significantly greater improvements in disability at both the short- and long-term follow-up periods and in pain at the 1-week follow-up compared with patients who received exercise only.
Trial registration: ClinicalTrials.gov NCT00504686.