Sagittal imbalance of the spine: compensatory mechanisms, radiographic assessment, clinical significance, and rehabilitation

Clinical question and importance: How should whole-body radiographic assessment be integrated with compensatory mechanisms to identify overt or masked sagittal imbalance and guide rehabilitation? Hypothesis and novelty: A systemic interpretation of spinopelvic parameters together with lower-limb posture identifies the cost of compensation more accurately than the sagittal vertical axis alone; this review proposes a radioclinical algorithm applicable to rehabilitation practice. Abstract Introduction: Sagittal imbalance had been associated with pain, fatigability, and functional limitation, yet an apparently acceptable sagittal vertical axis could conceal recruitment of the pelvis and lower limbs. This review aimed to synthesize the radiographic parameters, compensatory cascade, and implications for rehabilitation. Material and methods: A narrative search of PubMed/MEDLINE and the reference lists of relevant articles was conducted through 31 August 2026. Landmark studies, whole-body alignment cohorts, validated classifications, and syntheses of nonoperative treatment for adult spinal deformity were prioritized. Reporting was guided by the SANRA criteria. Results: The evidence supported integrated analysis of pelvic incidence, lumbar lordosis, the mismatch between them, pelvic tilt, sacral slope, sagittal vertical axis, and T1 pelvic angle. A normal sagittal vertical axis did not exclude compensated malalignment. Extension of mobile segments, reduction of thoracic kyphosis, pelvic retroversion, hip extension, knee flexion, ankle dorsiflexion, and cervical extension were described. Target values varied with age, and the evidence for radiographic correction through rehabilitation remained heterogeneous.