The aim of this study was to investigate, using quantitative sensory testing (QST) parameters and the painDETECT (PD-Q) screening questionnaire, the presence of neuropathic pain (NeP) in patients with unilateral painful cervical radiculopathy (CxRAD) and in patients with unilateral nonspecific neck-arm pain associated with heightened nerve mechanosensitivity (NSNAP).
All patients completed the PD-Q before QST. QST was performed bilaterally in the maximal pain area and the affected dermatome in 23 patients with painful C6 or C7 radiculopathy and in 8 patients with NSNAP following a C6/7 dermatomal pain distribution.
Patients with CxRAD demonstrated a significant loss of sensory function in mechanical (P≤0.021) and vibration sense (P≤0.003) on the symptomatic side compared with the asymptomatic side in both tested body regions and in the dermatome reduced cold detection (P=0.021) and pressure pain sensitivity (P=0.005), findings consistent with nerve root damage. These sensory alterations in the maximal pain area/symptomatic side are confirmative for the presence of NeP. In contrast to these QST data, only 30% of patients with CxRAD demonstrated a NeP component according to the PD-Q score. In patients with NSNAP, a significant side-to-side difference was demonstrated for warm detection threshold in the dermatome (P=0.030). The PD-Q score indicated that NeP components were unlikely in this group.
QST data suggest that NeP is likely to be observed in patients with painful CxRAD, but not in patients with NSNAP.