Poster Presentation Sydney Spinal Symposium 2025

Mixed Pain in Low Back Pain: Clinical and Cognitive Correlations of Overlapping Mechanisms (#23)

Owen Zhou 1
  1. Spine Labs, Kogarah, NSW, Australia

Background

Low back pain (LBP) is a leading cause of disability worldwide1, yet the majority of cases are classified as “non-specific”, lacking a clearly defined pathophysiological basis2. Mechanistic phenotyping offers a promising framework by distinguishing nociceptive (NoP), neuropathic (NeP), and nociplastic (NcplP) pain mechanisms3. Recent literature increasingly recognises a substantial subset of patients with mixed pain (MixP) – those exhibiting overlapping features of NoP, NeP, and NcplP – yet clinical understanding of this phenotype remains limited4,5. 

Existing evidence suggests MixP is prevalent, yet underdiagnosed, and associated with greater symptom severity, functional impairment, and psychological burden compared to singular pain phenotypes6. 

Objective

The study explores the evolving conceptualisation of MixP in LBP, with a focus on its clinical and cognitive correlates. The study seeks to evaluate the associations between MixP (as classified by the painDETECT questionnaire) and outcomes including pain intensity, disability, quality of life, and cognitive-emotional factors.

A retrospective analysis of a prospectively collected tertiary clinic database will be conducted, incorporating patient-reported outcomes (NRS, EQ-5D, ODI, modified NASS-LS) and radiographic data. The study aims to clarify the symptom burden of MixP relative to NoP and NeP groups, and to assess whether mixed mechanisms predict poorer clinical outcomes. Though data collection is ongoing, preliminary trends indicate notable differences between pain phenotypes in pain quality and the presence of pain beyond the low back region. Findings are anticipated to inform more targeted and mechanism-based approaches to LBP management and to address a key gap in current phenotyping models.

  1. 1. Ferreira, M. L. et al. Global, regional, and national burden of low back pain, 1990–2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021. The Lancet Rheumatology 5, e316–e329 (2023).
  2. 2. Chiarotto, A. & Koes, B. W. Nonspecific Low Back Pain. New England Journal of Medicine 386, 1732–1740 (2022).
  3. 3. Lapkin, S., Sima, S., Gan, Z. & Diwan, A. D. A confirmatory factor analysis of an electronic format painDETECT questionnaire for patients with low back pain. Current Medical Research and Opinion 40, 259–265 (2024).
  4. 4. Freynhagen, R. et al. Current understanding of the mixed pain concept: a brief narrative review. Current Medical Research and Opinion 35, 1011–1018 (2019).
  5. 5. Nijs, J., De Baets, L. & Hodges, P. Phenotyping nociceptive, neuropathic, and nociplastic pain: who, how, & why? Braz. J. Phys. Ther. 27, 100537 (2023).
  6. 6. Ibor, P. J., Sánchez-Magro, I., Villoria, J., Leal, A. & Esquivias, A. Mixed pain can be discerned in the primary care and orthopedics settings in Spain: a large cross-sectional study. The Clinical Journal of Pain 33, 1100–1108 (2017).