Sagittal Alignment as a Determinant of Pain and Functional Recovery after Lumbar Surgery: A Systematic Review and Meta-Analysis.

Abstract

Background: Sagittal alignment is increasingly recognized as a key determinant of functional recovery after lumbar spine surgery; however, its role in degenerative lumbar disease remains variably reported. While alignment principles are well-established in adult spinal deformity, their applicability to routine degenerative procedures has not been quantitatively synthesized.

Methods: A systematic review and meta-analysis of 23 original clinical studies (1,837 adults) was performed. Eligible studies reported postoperative sagittal or spinopelvic parameters-pelvic incidence (PI)-lumbar lordosis (LL) mismatch, sagittal vertical axis, LL, pelvic tilt, or segmental lordosis-and at least one validated clinical outcome (Oswestry Disability Index, visual analogue scale/numerical rating scale, 12-Item Short Form Health Survey, EuroQol Five Dimensions, Core Outcome Measures Index, Japanese Orthopaedic Association). Continuous data were converted to log-odds ratios (ORs) (Chinn method) to enable unified pooling. Random-effects models were applied for disability and pain outcomes. Subgroup analyses assessed fusion versus decompression, PI-LL versus other alignment metrics, and short-term versus long-term follow-up.

Results: Eight studies contributed disability outcomes, yielding a pooled OR of 0.33 (95% confidence interval [CI] 0.16-0.65), indicating a 67% reduction in the odds of significant postoperative disability in aligned patients. Five studies contributed pain data, producing a pooled OR of 0.39 (95% CI 0.25-0.61), corresponding to a 61% lower likelihood of persistent postoperative pain. Fusion procedures demonstrated stronger alignment-associated benefit (OR 0.34) compared with decompression alone (OR 0.56). PI-LL-based studies showed consistent predictive value (OR 0.48), and the alignment effect increased with long-term follow-up (>12 months; OR ~0.28). Qualitatively, 87% of studies reported positive alignment-outcome associations.

Conclusion: Restoration of physiological sagittal alignment significantly improves postoperative disability and pain across degenerative lumbar procedures. Alignment correction should be considered a central element of surgical planning in both fusion and decompression.