Reliability and validity of a palpation technique for identifying the spinous processes of C7 and L5

The objective was to examine inter-tester reliability and validity of two therapists identifying the spinous processes (SP) of C7 and L5, using one predefined surface palpation procedure for each level. One identification method made it possible to examine the reliability and the validity of the procedure itself. Two manual therapists examined 49 patients (29 women). Aged between 26 and 79 years, 18 were cervical and 31 lumbar patients. An invisible marking pen and ultraviolet light were used, and the findings were compared. X-rays were taken as an objective measure of the correct spinal level. Percentage agreement and kappa statistics were used to evaluate reliability and validity. The best inter-therapist agreement was found for the skin marks. Percentage agreement within 10mm and 20mm was 67% and 85%, respectively. The inter-tester reliability for identifying a radiological nominated SP by palpation was found to be poor for C7 and moderate for L5, with kappa of 0.18 and 0.48, respectively. The results indicated acceptable inter-therapist surface palpation agreement, but the chosen procedures did not identify the correct SP. This indicates that the procedures are not precise enough. Future reliability studies should test other non-invasive palpation procedures, both individually and in combination, and compare these with radiological investigation.