Prognostic Factors for the Postoperative Improvement of Spinal Cord-Related Neuropathic Pain in Patients with Degenerative Cervical Myelopathy

Hideaki Nakajima; Shuji Watanabe; Kazuya Honjoh; Arisa Kubota; Hideaki Matsuo; Hiroaki Naruse; Akihiko Matsumine

doi:10.22603/ssrr.2021-0248

Prognostic Factors for the Postoperative Improvement of Spinal Cord-Related Neuropathic Pain in Patients with Degenerative Cervical Myelopathy

Spine Surg Relat Res. 2022 Apr 12;6(6):610-616. doi: 10.22603/ssrr.2021-0248. eCollection 2022 Nov 27.

Authors

Hideaki Nakajima¹, Shuji Watanabe¹, Kazuya Honjoh¹, Arisa Kubota¹, Hideaki Matsuo², Hiroaki Naruse², Akihiko Matsumine¹

Affiliations

¹ Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences University of Fukui, Fukui, Japan.
² Division of Physical Therapy and Rehabilitation Medicine, University of Fukui Hospital, Fukui, Japan.

Abstract

Introduction: The number of patients with degenerative cervical myelopathy (DCM) requiring surgical treatment has markedly increased in today's aging society. Such patients often exhibit impaired activities of daily living because of motor dysfunction as well as neuropathic pain (NeP). Although many studies have demonstrated the safety and efficacy of surgical treatment for DCM, residual postoperative NeP has not been well described. Therefore, this study aimed to identify the predictors of postoperative NeP improvement in patients with DCM.

Methods: This retrospective study included 92 outpatients with postoperative chronic NeP (≥3 months) related to DCM. Data were obtained from clinical information, magnetic resonance imaging (MRI) findings, and patient-based questionnaires using the Neuropathic Pain Symptom Inventory (NPSI) and the Brief Scale for Psychiatric Problems in Orthopaedic Patients. Univariate and multivariate analyses were performed for patients with NPSI improvement rates <30% and ≥30% to identify prognostic factors.

Results: Among 92 patients, 61 (66.3%) had residual NeP, with a low improvement rate even after surgery. The independent negative prognostic factors for NeP improvement after surgery were older age at operation (odds ratio (OR): 0.932), longer symptom duration before surgery (OR: 0.589), and higher preoperative NPSI score (OR: 0.932). The cut-off value of symptom duration before surgery for postoperative NeP improvement was 1 year. By contrast, the preoperative Japanese Orthopaedic Association score and MRI findings, including signal intensity change and the degree of spinal cord compression, were not associated with postoperative NeP improvement. Moreover, even in patients with an NPSI improvement rate ≥30%, the NPSI subscores for deep pain and paresthesia/dysesthesia remained high.

Conclusions: Discrepancies between physician- and image-based assessments and patient-based assessments were identified as factors associated with improvement in postoperative NeP. Our findings are important for both spine surgeons and patients to manage patient expectations with respect to recovery during the postoperative course.

Keywords: degenerative cervical myelopathy; neuropathic pain; patient-based questionnaires; postoperative improvement; prognostic factors; spinal cord-related pain.