Neuropathic pain as a predictor of neurological disorders regression in patients with spinal cord traumatic injury

Abstract

Background. Neuropathic pain is one of the principal secondary complications of spinal cord injury. The biological role of neuropathic pain has not been established yet. This type of pain is formed directly in the area of the spinal cord injury; therefore, it can be assumed that its intensity may characterize both degenerative and reparative processes. The aim of this work is to assess the possible relationship between the intensity of neuropathic pain in patients with spinal cord injury at cervical subaxial spine and the dynamics of neurological disorder regression. Materials and methods. We have performed a retrospective analysis of patients referred to outpatient department of the Romodanov Neurosurgery Institute of National Academy of Medical Sciences of Ukraine in the period from 2010 to 2020 after a surgical treatment of subaxial cervical spine traumatic injury. The extent of neurological disorders and the intensity of neuropathic pain were assessed within 5–7 and 11–13 months after surgery. Results. All 102 patients selected for analysis were divided into three groups depending on the intensity of the registered pain sensations: 1) absence of constant pain sensations — 19.6 % of subjects, 2)moderate pain— 56.9 %, 3) severe neuropathic pain — 23.5 %. In the first group, the regression of neurological disorders was 3.5 (95% confidence interval (CI) 2.15–6.15), in the second — 25.0 (95% CI 24.14–29.58), in the third — 13.0 (95% CI 10.87–16.55). The differences are statistically significant (χ2 = 60.4, df = 2, p < 0.0001). In patients with severe neurological disorders, the dynamics of recovery did not correlate with the pain intensity. With ASIA B, the dynamics of group 1 was 8.5 (95% CI 10.56–27.56), of group 2— 15.0 (95% CI 13.41–18.41), of group 3 — 10.5 (95% CI 7.45–14.89). With ASIA C functional class, the difference is even more pronounced: in group 1, the median was 8.0 (95% CI 0.83–20.83), in group 2 — 32.0 (95% CI 25.41–36.86), in group 3 — 15.5 (95% CI 10.27–27.4). With ASIA D, a similar trend was observed. Conclusions. The worst regression of neurological disorders is observed in patients without clinically significant pain, the best results of neurological dysfunction recovery are found in patients with mode rate neuropathic pain.