A Silver Lining of Neuropathic Pain: Predicting Favorable Functional Outcome in Spinal Cord Injury

Mu-Lan Xu; Xiang-Bo Wu; Ying Liang; Ning Li; Xu Hu; Xiao-Dong Lin; Miao-Qiao Sun; Chun-Qiu Dai; Dan Niu; Yan-Rong Zhang; Hui Cao; Chen-Guang Zhao; Xiao-Long Sun; Hua Yuan

doi:10.2147/JPR.S414638

A Silver Lining of Neuropathic Pain: Predicting Favorable Functional Outcome in Spinal Cord Injury

J Pain Res. 2023 Jul 27:16:2619-2632. doi: 10.2147/JPR.S414638. eCollection 2023.

Authors

Mu-Lan Xu^#^{1

2}, Xiang-Bo Wu^#¹, Ying Liang^#³, Ning Li¹, Xu Hu¹, Xiao-Dong Lin¹, Miao-Qiao Sun¹, Chun-Qiu Dai¹, Dan Niu¹, Yan-Rong Zhang¹, Hui Cao¹, Chen-Guang Zhao¹, Xiao-Long Sun¹, Hua Yuan¹

Affiliations

¹ Department of Rehabilitation Medicine, Xi-Jing Hospital, Air Force Medical University (Fourth Military Medical University), Xi'an, Shaanxi, People's Republic of China.
² Department of Rehabilitation Medicine, Shenshan Medical Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Shanwei, Guangdong, People's Republic of China.
³ Department of Health Statistics, Air Force Medical University (Fourth Military Medical University), Xi'an, Shaanxi, People's Republic of China.

^# Contributed equally.

Abstract

Background: Neuropathic pain (NP) is a common and severe problem following spinal cord injury (SCI). However, its relationship with functional outcome remains unclear.

Methods: A retrospective explorative analysis was performed on SCI patients admitted to a tertiary academic medical center between January 2018 and June 2022. The candidate predictor variables, including demographics, clinical characteristics and complications, were analyzed with logistic and linear regression. Spinal Cord Independence Measure (SCIM) scores at discharge and mean relative functional gain (mRFG) of SCIM were as outcome parameters.

Results: A total of 140 SCI patients included for the final analysis. Among them, 44 (31.43%) patients were tetraplegics, and 96 (68.57%) patients were paraplegics; 68 (48.57%) patients developed NP, and 72 (51.43%) patients did not. Logistic and linear regression analyses of SCIM at discharge both showed that NP [OR=3.10, 95% CI (1.29,7.45), P=0.01; unstandardized β=11.47, 95% CI (4.95,17.99), P<0.01; respectively] was significantly independent predictors for a favorable outcome (SCIM at discharge ≥ 50, logistic regression results) and higher SCIM total score at discharge (linear regression results). Besides, NP [unstandardized β=15.67, 95% CI (8.94,22.41), P<0.01] was also independently associated with higher mRFG of SCIM scores. Furthermore, the NP group had significantly higher mRFG, SCIM total scores and subscales (self-care, respiration and sphincter management, and mobility) at discharge compared to the non-NP group. However, there were no significant differences in mRFG, SCIM total score or subscales at discharge among the NP subgroups in terms of locations (at level pain, below level pain, and both) or timing of occurrence (within and after one month after SCI). This study also showed that incomplete injury, lumbar-sacral injury level and non-anemia were significantly independent predictors for a favorable outcome, and higher mRFG of SCIM scores (except for non-anemia).

Conclusion: NP appears independently associated with better functional recovery in SCI patients, suggesting the bright side of this undesirable complication. These findings may help to alleviate the psychological burden of NP patients and ultimately restore their confidence in rehabilitation.

Keywords: SCIM; functional outcome; mRFG; neuropathic pain; retrospective study; spinal cord injury.

Grants and funding

This work was supported by National Natural Science Foundation of China [grant numbers 82072534, 82272591], Shanxi Provincial Key R&D Program-International Science and Technology Cooperation Program [grant number 2020KW-050], and Young Elite Scientists Sponsorship Program by CAST [grant number 2018QNRC001].