Pelvic incidence–lumbar lordosis mismatch in non-specific low back pain: Associations with pain, disability and lumbar structural findings — A retrospective cross-sectional study

BackgroundPelvic incidence-lumbar lordosis (PI-LL) mismatch is associated with adverse outcomes in spinal deformity, but its relevance in nonspecific low back pain (LBP) is unclear.ObjectiveTo assess whether PI-LL mismatch is associated with pain, disability, symptom duration and structural findings in nonspecific LBP.MethodsIn this retrospective cross-sectional study, consecutive patients aged 30-65 years with conservatively managed nonspecific LBP ≥4 weeks and lumbar magnetic resonance imaging plus standing lateral radiography from May 2022 to May 2023 were identified from hospital records and assessed at a single standardized visit between May 2023 and February 2024. Pelvic incidence and L1-S1 lordosis were measured; mismatch was defined as ≥10°. Pain (visual analogue scale, VAS), disability (Oswestry Disability Index, ODI), facet tropism (facet angle asymmetry >7°), and Goutallier-graded paraspinal fatty infiltration were assessed. Groups were compared with parametric and non-parametric tests and multivariable linear regression; the sample could detect d = 0.55 (80% power, α = 0.05).ResultsOf 105 patients, 51 had a mismatch. VAS, symptom duration and ODI were higher in the mismatch group. After adjustment, a mismatch remained independently associated with higher VAS and longer duration, but not with ODI. Facet tropism was more prevalent at L4-5 and L5-S1, and multifidus fatty infiltration was higher at L2-3.ConclusionIn conservatively managed nonspecific LBP, PI-LL mismatch was independently associated with greater pain and longer symptom duration and co-occurred with segment-specific structural changes. Prospective studies are needed to establish its prognostic values.