Intra- and inter-rater reliability of 3D passive intervertebral motion in subjects with non-specific neck pain assessed by physical therapy students: A pilot study

BACKGROUND: Passive Intervertebral Movements (PIVMs) are commonly used to assess and treat patients with non-specific neck pain. Only very few studies have investigated 3D movements until now. OBJECTIVE: This study assessed intra- and inter-rater reliability of three-dimensional (3D) cervical PIVMs performed by physical therapy students in patients with non-specific neck pain. METHODS: Thirty-one patients, mean age 47.2 ± 7.2 years, were independently evaluated by 2 physical therapy students. The raters (A and B) assessed mobility, end-feel and pain provocation performing bilaterally the 3D cervical segmental sidebending test (3D CSSB) from levels C2-C3 to C6-C7. Percentage agreement (raw, positive and negative), Cohens kappa (95% CI), prevalence index and bias index were calculated to estimate intra- and inter-reliability. RESULTS: Intra-rater reliability showed kappa values ranging between fair and substantial (k 0.29-0.80) for pain provocation, mobility and end-feel, with percentage agreements between 61%-90%. Inter-rater reliability presented kappa values ranging between fair and substantial (k 0.22-0.62) for pain provocation, mobility and end-feel, with percentage agreements between 61% and 80%. CONCLUSIONS: Intra-rater reliability of 3D PIVMs was superior to inter-rater reliability in patients with non-specific neck pain. The most repeatable evaluation parameter was pain. However overall poor reliability suggests avoiding the use of these techniques alone to examine patients and measure their outcome. Further studies are needed to investigate PIVMs reliability in combination with other assessment procedure in symptomatic patients.