Development of a clinical prediction rule to identify patients with neck pain likely to benefit from cervical traction and exercise.

The objective of the study was to develop a clinical prediction rule (CPR) to identify patients with neck pain likely to improve with cervical traction. The study design included prospective cohort of patients with neck pain referred to physical therapy. Development of a CPR will assist clinicians in classifying patients with neck pain likely to benefit from cervical traction. Eighty patients with neck pain received a standardized examination and then completed six sessions of intermittent cervical traction and cervical strengthening exercises twice weekly for 3 weeks. Patient outcome was classified at the end of treatment, based on perceived recovery according to the global rating of change. Patients who achieved a change > or =+6 ("A great deal better" or "A very great deal better") were classified as having a successful outcome. Univariate analyses (t tests and chi-square) were conducted on historical and physical examination items to determine potential predictors of successful outcome. Variables with a significance level of P < or = 0.15 were retained as potential prediction variables. Sensitivity, specificity and positive and negative likelihood ratios (LRs) were then calculated for all variables with a significant relationship with the reference criterion of successful outcome. Potential predictor variables were entered into a step-wise logistic regression model to determine the most accurate set of clinical examination items for prediction of treatment success. Sixty-eight patients (38 female) were included in data analysis of which 30 had a successful outcome. A CPR with five variables was identified: (1) patient reported peripheralization with lower cervical spine (C4-7) mobility testing; (2) positive shoulder abduction test; (3) age > or =55; (4) positive upper limb tension test A; and (5) positive neck distraction test. Having at least three out of five predictors present resulted in a +LR equal to 4.81 (95% CI = 2.17-11.4), increasing the likelihood of success with cervical traction from 44 to 79.2%. If at least four out of five variables were present, the +LR was equal to 23.1 (2.5-227.9), increasing the post-test probability of having improvement with cervical traction to 94.8%. This preliminary CPR provides the ability to a priori identify patients with neck pain likely to experience a dramatic response with cervical traction and exercise. Before the rule can be implemented in routine clinical practice, future studies are necessary to validate the rule. The CPR developed in this study may improve clinical decision-making by assisting clinicians in identifying patients with neck pain likely to benefit from cervical traction and exercise.