Myofascial trigger points in patients with whiplash-associated disorders and mechanical neck pain

Objective: The aim of this study was to investigate pain patterns and the distribution of myofascial trigger points (MTPs) in whiplash-associated disorders (WADs II and III) as compared with mechanical neck pain (MNP). Methods: Manual examination of suboccipital, upper trapezius, elevator scapula, temporalis, supraspinatus, infraspinatus, deltoid, and sternocleidomastoid muscles, was done to search for the presence of both active or latent MTPs in 49 WAD patients and 56 MNP patients. Local pain and referred pain from each active MTP was recorded on an anatomical map. Results: The mean number of active MTPs was significantly greater in the WAD group (6.71±0.79) than in the MNP group (3.26±0.33) (P<0.001), but this was not found for the latent MTPs (3.95±0.57 vs 2.82±0.34; P>0.05). In the WAD group, the current pain intensity (visual analogue scale) of the patients was significantly correlated with the number of active MTPs (r_s=0.03, P=0.03) and the spontaneous pain area (r_s=0.25, P=0.07), and the number of active MTPs was significantly correlated with the spontaneous pain area (r_s=0.3, P=0.03). In the MNP group, significant correlation was found only between pain duration and spontaneous pain area (r_s=0.29, P=0.02). Conclusions: Active MTPs are more prominent in WAD than MNP and related to current pain intensity and size of the spontaneous pain distribution in whiplash patients. This may underlie a lower degree of sensitization in MNP than in WAD.