Predictors of short-term outcome in people with a clinical diagnosis of cervical radiculopathy

Abstract

Background and purpose: The purpose of this prospective cohort study was to identify whether variables from the baseline examination or physical therapy interventions received could predict clinical outcomes for people with cervical radiculopathy.

Subjects and methods: A total of 96 consecutive patients referred for physical therapy for cervical radiculopathy were the sources of data for this study. All subjects underwent a standardized examination and completed the Neck Disability Index (NDI), the Patient-Specific Functional Scale (PSFS), and the Numeric Pain Rating Scale (NPRS) at baseline and at discharge. The subjects were treated according to the discretion of the individual therapists. At the time of discharge, the subjects completed the Global Rating of Change as well. Subjects surpassing the minimal clinically important change for all 4 outcome tools were categorized as achieving short-term success. Individual variables from the examination and interventions provided were tested for univariate relationships with outcomes. Variables with a significance level of less than .10 were retained as potential predictor variables and were entered into a stepwise logistic regression model to determine the most accurate set of variables for predicting outcomes.

Results: The pretest probability for the likelihood of short-term (28-day follow-up) success was 53%. A 4-variable model optimally identified subjects who were most likely to achieve success with physical therapy interventions (age of <54 years; dominant arm is not affected; looking down does not worsen symptoms; and multimodal treatment including manual therapy, cervical traction, and deep neck flexor muscle strengthening for at least 50% of visits). When 3 of these 4 variables were present, the positive likelihood ratio (+LR) was 5.2 (95% confidence interval [CI]=2.4, 11.3), and the posttest probability of success was 85%. When all 4 variables were present, the +LR was 8.3 (95% CI=1.9, 63.9), and the posttest probability of success was 90%.

Discussion and conclusion: These results suggest that a subset of predictor variables can accurately identify which people with cervical radiculopathy are likely to experience short-term successful outcomes. The study design did not allow for the identification of a cause-and-effect relationship, but it appears that intermittent cervical traction, manual therapy, and deep neck flexor muscle strengthening may be beneficial in the management of cervical radiculopathy. Future research is needed to substantiate these findings.