Quantitative sensory testing somatosensory profiles in patients with cervical radiculopathy are distinct from those in patients with nonspecific neck–arm pain

The aim of this study was to establish the somatosensory profiles of patients with cervical radiculopathy and patients with nonspecific neck–arm pain associated with heightened nerve mechanosensitivity (NSNAP). Sensory profiles were compared to healthy control (HC) subjects and a positive control group comprising patients with fibromyalgia (FM). Quantitative sensory testing (QST) of thermal and mechanical detection and pain thresholds, pain sensitivity and responsiveness to repetitive noxious mechanical stimulation was performed in the maximal pain area, the corresponding dermatome and foot of 23 patients with painful C6 or C7 cervical radiculopathy, 8 patients with NSNAP in a C6/7 dermatomal pain distribution, 31 HC and 22 patients with FM. For both neck–arm pain groups, all QST parameters were within the 95% confidence interval of HC data. Patients with cervical radiculopathy were characterised by localised loss of function (thermal, mechanical, vibration detection P < 0.009) in the maximal pain area and dermatome (thermal detection, vibration detection, pressure pain sensitivity P < 0.04), consistent with peripheral neuronal damage. Both neck–arm pain groups demonstrated increased cold sensitivity in their maximal pain area (P < 0.03) and the foot (P < 0.009), and this was also the dominant sensory characteristic in patients with NSNAP. Both neck–arm pain groups differed from patients with FM, the latter characterised by a widespread gain of function in most nociceptive parameters (thermal, pressure, mechanical pain sensitivity P < 0.027). Despite commonalities in pain characteristics between the 2 neck–arm pain groups, distinct sensory profiles were demonstrated for each group