Somatosensory and clinical profiles of patients with spine-related and clinical framework-based neck–arm pain

Spine-related neck-arm pain is heterogeneous and may present on a spectrum between nociceptive and neuropathic pain. A recently developed mechanism-based clinical framework for spine-related pain distinguishes between spinally referred pain without neurological deficits (somatic referred pain, heightened nerve mechanosensitivity, radicular pain), with neurological deficits (radiculopathy), and mixed-pain presentations. This study investigated differences in somatosensory and clinical profiles of patients with unilateral spine-related neck-arm pain grouped according to the clinical framework. Patients (n = 113) underwent a clinical examination, after which they were classified into a subgroup(s). They completed questionnaires to assess function (Neck Disability Index), psychosocial factors (Tampa Scale of Kinesiophobia, pain catastrophizing scale, Depression, anxiety, and stress scale), neuropathic pain (Douleur neuropathique 4), and central sensitization features (Central Sensitization Inventory). Standardized quantitative sensory testing (QST) was performed over the maximal pain area and contralateral side. The radiculopathy group showed a significant loss of function on the symptomatic vs asymptomatic side in cold ( P = 0.024) and warm detection ( P = 0.004), thermal sensory limen ( P = 0.001), mechanical detection ( P = 0.001), increased windup ratio ( P = 0.014), and cold hyperalgesia ( P = 0.049). No other subgroup showed significant side differences in QST parameters. Symptom descriptors, such as burning ( P < 0.031), tingling ( P < 0.018), pins and needles ( P < 0.031), numbness ( P < 0.016), spontaneous pain ( P < 0.001), and electric pain/shock ( P < 0.026) were more common in the radicular/radiculopathy groups compared with the somatic/mechanosensitivity groups. There were no differences in psychosocial parameters between the groups. The phenotypic profiles support the construct of the clinical examination and patient classification and its application in clinical practice according to a clinical framework for spine-related pain.