Day: July 10, 2026

J Neurosurg Spine 45:44–54, 2026

This clinical study evaluates how pelvic incidence (PI) affects spinopelvic correction and proximal junctional failure (PJF) after long-segment thoracolumbar fusion with pelvic fixation in 204 adult spinal deformity patients. Patients were stratified by PI (<55° vs >55°) and analyzed for radiographic outcomes, complications, and PROMs using frequentist and Bayesian models.

Key findings show lower PI independently predicts higher PJF risk (21% vs 9%), with lower thoracic UIV and revision surgery as additional predictors; lower PI patients more often met age-adjusted alignment goals but experienced greater overcorrection relative to individualized morphology.

Objective Evaluate how pelvic incidence (PI) affects spinopelvic correction and complication rates (especially proximal junctional pathology) after long-segment fusion for adult spinal deformity.

Cohort Retrospective analysis of 204 patients undergoing open posterior long-segment thoracolumbar fusion with pelvic fixation (≥ 6 levels) with ≥ 1-year follow-up; grouped by PI cutoff 55° into lower PI (n=108) vs higher PI (n=96).

Primary finding (PJF rates) Lower PI patients had higher proximal junctional failure (PJF) at 1 year than higher PI patients (21% vs 9%, p=0.019).

UIV subgroup With an upper thoracic UIV (T2–5), PJF was 15% in lower PI vs 0% in higher PI (p=0.014).

Independent predictors Multivariate analysis: lower PI (OR 4.3, p=0.006), lower thoracic UIV (T10–12) (OR 6.5, p=0.005), and revision surgery (OR 23.8, p=0.001) independently predicted PJF.

Model confirmation Bayesian mixed-effects modeling also identified lower PI (OR 6.25, posterior probability 0.996) and lower thoracic UIV (OR 7.03, posterior probability 0.997) as significant predictors of PJF.

PJK vs PJF Proximal junctional kyphosis (PJK) rates were similar between PI groups at 1 year (38% vs 41%, p=0.697), despite the PJF difference.

Planning implication Preoperative PI morphology may guide individualized surgical planning to reduce risk of junctional pathology, since lower PI carried higher PJF risk after long-segment fusion.