Multilevel Stabilization Screws Prevent Proximal Junctional Failure and Kyphosis in Adult Spinal Deformity Surgery: A Comparative Cohort Study

Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) occurred in up to 40% of patients with adult spinal deformity (ASD) who underwent open thoracolumbar fusion. Proximal stabilization techniques have been investigated to prevent PJK/PJF without conclusive results.To demonstrate reductions in PJK/PJF with multilevel stabilization screws (MLSSs).This observational longitudinal cohort study compares MLSSs with standard instrumentation. We reviewed the charts of consecutive patients with ASD undergoing open thoracolumbar fusion (3 levels, extending cranially above T6 and caudally below L1) from 2009 to 2017 and were followed for2 yr postoperatively. We defined PJF using the International Spine Study Group criteria and PJK as a Cobb angle increase10°. We defined the upper instrumented vertebra as the most cephalad vertebral body with bilateral MLSSs. Confounders, MLSS-specific complications, and radiographic outcomes were collected. We evaluated comparability between groups using univariate analyses. We adjusted for covariates by using multivariable regressions modeling PJF and PJK separately with a P-value.00625 considered significant after the Bonferroni correction. Sensitivity analysis accounted for those lost to follow-up.Seventy-six patients (50 MLSS vs 26 controls) were included. MLSS patients were significantly older (64.5 ± 8.9 vs 54.8 ± 19.9 yr, P = .024) and had significantly lower PJF incidence (10.0% vs 30.8%, P = .023) and less kyphosis (1.3° ± 5.3° vs 5.2° ± 6.3°, P = .014). Multivariable analysis demonstrated a significant independent association between MLSSs and decreased odds of PJF (odds ratio: 0.11, 0.02-0.53, P = .006). Perioperative complications did not significantly differ between cohorts.MLSSs are safe and efficacious in reducing PJF/PJK in patients with ASD undergoing open thoracolumbar fusion.