Widespread Pressure Pain Hyperalgesia in Chronic Nonspecific Neck Pain with Neuropathic Features: A Descriptive Cross-Sectional Study

Background: Neck pain has an elevated prevalence worldwide. Most people with neck pain arediagnosed as nonspecific neck pain patients. Poor recovery in neck disorders, as well as high levels of painand disability, are associated with widespread sensory hypersensitivity. Nevertheless, there is controversyregarding the presence of widespread hyperalgesia in chronic nonspecific neck pain (CNSNP); this lackof agreement could be due to the presence of different pathophysiological mechanisms in CNSNP.Objectives: To determinate differences in pressure pain thresholds (PPTs) over extracervical and cervicalregions, and differences in cervical range of motion (ROM) between patients with CNSNP with andwithout neuropathic features (NF and No-NF, respectively). In addition, this study expected to observecorrelations in these 2 types of CNSNP of psychosocial factors with PPTs and with cervical ROM separately.Study Design: Descriptive, cross-sectional study.Setting: A hospital physiotherapy outpatient department.Methods: This research involved 53 patients with CNSNP that had obtained a Self-completed LeedsAssessment of Neuropathic Symptoms and Signs pain scale (S-LANSS) score ≥ 12 (pain with NF, NFgroup); 54 that had obtained a S-LANSS score < 12 (pain with No-NF, No-NF group), and 53 healthycontrols (control group, CG). Measures included: PPTs (suboccipital muscle, upper fibers trapeziusmuscle, lateral epicondyle, and anterior tibial muscle), cervical ROM (flexion, extension, rotation, andlatero-flexion), pain intensity (Visual Analog Scale [VAS]), neck disability index (NDI), kinesiophobia(Tampa Scale of Kinesiophobia-11 [TSK-11]), and Pain Catastrophizing Scale (PCS).Results: A statistically significant effect was observed for the group factor in all assessed measures (P <0.01). Both CNSNP groups showed statistically significant differences compared to the CG for PPTs in thecervical region (suboccipital and upper fibers trapezius muscles), but only the NF group demonstratedstatistically significant differences for PPTs in the lateral epincondyle and anterior tibial muscle whencompared to the CG or No-NF group. The largest statistically significant correlation found in the NFgroup was between PPT in the anterior tibial muscle and TSK-11 (r = -0.372; P < 0.01), while in theNo-NF group it was between PPT in the suboccipital muscle and NDI (r = -0.288; P < 0.05). Statisticallysignificant differences were found between the 2 CNSNP groups and CG in all cervical ROMs, but notbetween both CNSNP groups. The largest statistically significant correlation observed in the NF groupwas between cervical total rotation and TSK-11 (r = -0.473; P < 0.01), while in the No-NF group it wasbetween cervical total latero-flexion and PCS (r = -0.532; P < 0.01).Limitations: Although the S-LANSS scale has been validated as a screening tool for pain with NF,currently there is no “gold standard,” so these findings should be interpreted with caution.Conclusions: Widespread pressure pain hyperalgesia was detected in patients with CNSNP with NF,but not in patients with CNSNP with No-NF. Patients with CNSNP presented bilateral pressure painhyperalgesia over the cervical region and a decreased cervical ROM compared to healthy controls.However, no differences were found between the 2 CNSNP groups. These findings suggest differencesin the mechanism of pain processing between patients with CNSNP with NF and No-NF.Key words: Neck pain, chronic pain, neuropathic pain, pain threshold, mechanical hyperalgesia,range of motion, pain catastrophizing