Prevalence of neuropathic pain in cases with chronic pain related to spinal disorders

The incidence and characteristics of neuropathic pain associated with spinal disorders have not yet been fully clarified. The purpose of this study was to investigate the prevalence of neuropathic pain and the degree of deterioration of quality of life (QOL) in patients with chronic pain associated with spinal disorders who visited orthopedic outpatient clinics.

This cross-sectional study was conducted in 1,857 patients recruited from 137 medical institutions nationwide. Participants were men and women aged 20-79 years with a history of spine-related pain for at least 3 months and a visual analog scale (VAS) score of at least 30 in the previous week. Patients were screened using a neuropathic pain screening questionnaire. The degree of QOL deterioration and its correlation with the presence of neuropathic pain were assessed using the Short Form Health Survey with 36 questions (SF-36).

Overall prevalence of neuropathic pain was 53.3%. It was relatively high in patients with cervical spondylotic myelopathy (77.3%) and ligament ossification (75.7%) and relatively low in those with low back pain (29.4%) and spondylolysis (40.4%). Only 56.9% of patients with radiculopathy were diagnosed with neuropathic pain. Logistic regression analysis identified several risk factors, including advanced age, severe pain, disease duration of at least 6 months, and cervical lesions. In QOL assessment, physical functioning, role-physical, role-emotional, and social functioning were severely affected, and this trend was more pronounced in patients who were more likely to have neuropathic pain.

The frequency of neuropathic pain tended to be higher in patients with diseases associated with spinal cord damage and lower in patients with diseases that primarily manifested as somatic pain. A bias toward allodynia symptoms in the screening questionnaire may have resulted in the failure to diagnose neuropathic pain in some patients with radiculopathy. Poor QOL, primarily from the aspect of physical functioning, was demonstrated in patients with neuropathic pain associated with spinal disorders.