Sensory characteristics of tender points in the lower back

Palpation of tender points in superficial tissue is commonly undertaken in the management of musculoskeletal pain. The sensory characteristics of digitally tender points (DTPs) have not been defined. This study had two major aims: 1) to characterise ‘Strain–Counterstrain’ DTPs, using quantitative sensory testing (QST) in participants with low back pain (LBP); 2) to compare corresponding points at lumbar sites in participants with LBP to those without LBP. Fifteen participants with LBP (9 females), mean (SD) Oswestry scores 20.8 (10.1)) and 15 participants without LBP (6 females) were included. QST was undertaken by a single examiner blind to the location of DTPs and included measurement of electrical detection and electrical pain threshold, thermal (hot/cold) detection and thermal pain threshold, vibration detection threshold and pressure-pain threshold. In participants with LBP, DTPs demonstrated significantly lower electrical detection and electrical pain thresholds compared to contralateral non-tender points (p < 0.0001). These findings may be indicative of altered central processing of Aβ afferents with terminal receptors at DTPs. Participants with LBP demonstrated elevated cold pain thresholds at lower back sites and at the peripheral shoulder site compared to participants without LBP (p < 0.001). This may also indicate augmented central pain processing in participants with LBP.