Chronic mechanical neck pain in adults treated by manual therapy: a systematic review of change scores in randomized clinical trials.

OBJECTIVE: This study provides a systematic analysis of group change scores in randomized clinical trials of chronic neck pain not due to whiplash and not including headache or arm pain treated with manual therapy.
METHODS: A comprehensive literature search of clinical trials of chronic neck pain treated with manual therapies up to December 2005. Only clinical trials scoring above 11.5 (Amsterdam-Maastricht Scale) were included in the analysis.
RESULTS: From 1980 citations, 19 publications were selected. Of the 16 trials analyzed (3 were rejected for poor quality), 9 involved spinal manipulation (12 groups), 5 trials (5 groups) were for spinal mobilization or nonmanipulative manual therapy (1 trial overlapped), and 2 trials (2 groups) involved massage therapy. No trials included trigger point therapy or manual traction of the neck. For manipulation studies, the mean effect size (ES) at 6 weeks for 7 trials (10 groups) was 1.63 (95% confidence interval [CI], 1.13-2.13); 1.56 (95% CI, 0.73-2.39) at 12 weeks for 4 trials (5 groups); 1.22 (95% CI, 0.38-2.06) from 52 to 104 weeks for 2 trials (2 groups). For mobilization studies, 1 trial reported an ES of 2.5 at 6 weeks, 2 trials reported full recovery in 63.8% to 71.7% of subjects at 7 to 52 weeks, and 1 trial reported greater than 2/10 point pain score reduction in 78.3% of subjects at 4 weeks. For massage studies, 1 reported an ES of 0.03 at 6 weeks, whereas the other reported mean change scores of 7.89/100 and 14.4/100 at 1 and 12 weeks of, respectively.
CONCLUSIONS: There is moderate- to high-quality evidence that subjects with chronic neck pain not due to whiplash and without arm pain and headaches show clinically important improvements from a course of spinal manipulation or mobilization at 6, 12, and up to 104 weeks posttreatment. The current evidence does not support a similar level of benefit from massage.