Relationship between Postoperative Neuropathic Pain and Clinical Scores in Patients with Cervical Ossification of the Posterior Longitudinal Ligament.

INTRODUCTION

Postoperative neuropathic pain (NeP) is common after surgery for cervical ossification of the posterior longitudinal ligament (cOPLL) and may affect clinical outcomes. The PainDETECT questionnaire (PDQ) is a widely used tool for evaluating NeP, while the Spine PDQ (SPDQ) was developed to improve specificity for spinal disorder-related NeP. This study aimed to evaluate postoperative NeP using PDQ and SPDQ and to examine their associations with clinical scores.

METHODS

A total of 234 patients (170 men and 64 women; mean age, 61.9 years) who underwent cOPLL surgery were analyzed and followed for more than 1 year across 13 institutions. NeP was assessed using PDQ (cutoff ≥13) and SPDQ (cutoff ≥0). Clinical outcomes included the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), the visual analogue scale (VAS), and the EuroQol 5-Dimensions 5-Level (EQ-5D-5L). Correlations between NeP scores and clinical outcomes were evaluated. Patients were stratified into four PDQ/SPDQ-based groups: Zone 1: PDQ-/SPDQ-, Zone 2: PDQ+/SPDQ-, Zone 3: PDQ-/SPDQ+, and Zone 4: PDQ+/SPDQ+, and clinical outcomes were compared among the groups.

RESULTS

PDQ showed significant correlations with all clinical outcomes. SPDQ correlated with VAS, EQ-5D-5L, and the bladder function and quality of life (QOL) domains of JOACMEQ but not with other JOACMEQ domains. The PDQ+ group demonstrated worse scores across all domains than the PDQ- group. The SPDQ+ group had higher VAS scores and lower EQ-5D-5L and JOACMEQ QOL scores than that of the SPDQ- group, with no differences in other JOACMEQ domains. Zone 4 had the poorest prognosis, whereas Zone 3 showed higher VAS scores than Zone 1 but preserved JOACMEQ and EQ-5D-5L scores.

CONCLUSIONS

PDQ was associated with detecting pain, functional deterioration, and reduced QOL, while SPDQ reflected pain-related aspects only. Combined PDQ/SPDQ assessment and zone classification may stratify NeP severity and its clinical relevance in patients with postoperative cOPLL.