Pain Sensitivity and Reliability of the Posterior-Anterior Central Vertebral Pressure as a Provocative Test in Lumbar Pain

Background: The posterior-anterior central vertebral pressure (PACVP) is a manual diagnostic test for spinal pain; however, its sensitivity and reliability remain underexplored. This study evaluated the pain sensitivity and reliability of the PACVP as a provocative test in lumbar pain. Method: This test-retest study involved 76 patients with lumbar pain attending outpatient physiotherapy in a tertiary hospital. Baseline pain-intensity was assessed using a visual analogue scale, while the lowest transcutaneous electrical nerve stimulation (TENS) threshold indicated TENS pain sensitivity. Two experienced physiotherapists assessed the patients' pain-intensity before and after PACVP at initial contact and after 48-hours. Differences in pain-intensity before and after PACVP were recorded as PACVP pain sensitivity. Descriptive statistics summarised data, while intra-class and inter-class correlation coefficients analysed the intra-rater and inter-rater reliabilities of PACVP, with precision measures. Pearson correlation coefficient analysed the relationship between variables at p < 0.05. Results: Intra-rater reliabilities for PACVP were ICC = 0.93 with SEM (0.17), CV (11.9%) and ICC = 0.96 with SEM (0.15), CV (8.80%); while inter-rater reliability was ICC = 0.90 with SEM (0.22), CV (12.5%). Pain-intensity provoked by PACVP was negatively related (p<0.05) to pain sensitivity to TENS, whereas pain sensitivity to PACVP was positively related (p<0.05) to pain sensitivity to TENS. Conclusion: The PACVP is a reliable test for lumbar pain. Pain-intensity provoked by PACVP is inversely related to pain sensitivity to TENS, while pain sensitivity to PACVP is directly related to pain sensitivity to TENS.