Coronal Plane Correction in Adults with Patient-Specific Rods

Retrospective cohort study.

To evaluate radiographic and patient-reported outcomes of adult spinal deformity (ASD) correction using patient-specific rods (PSRs), with emphasis on coronal alignment.

While the sagittal plane has long been the primary focus in ASD correction, coronal malalignment contributes significantly to pain, disability, and mechanical complications. PSRs have demonstrated utility in improving sagittal alignment, but their impact on coronal deformities remains under-investigated.

We retrospectively analyzed 118 patients who underwent thoracolumbar or lumbar fusion with UNiD™ PSRs at a single academic center (2014-2021). Inclusion criteria required preoperative radiographic evidence of scoliosis (Cobb angle ≥10°) or coronal imbalance (C7 plumb line deviation ≥30 mm). Radiographic parameters-including maximal coronal Cobb angle, absolute C7PL deviation, sagittal vertical axis (SVA), lumbar lordosis (LL), and pelvic tilt (PT)-as well as patient-reported outcomes (Oswestry Disability Index [ODI] and Numeric Rating Scale [NRS] for back and leg pain) were collected pre- and postoperatively. Patients were followed up to 2 years. Complications and reoperations were documented. Paired t-tests and multivariate regression analyses assessed changes and predictors of postoperative alignment.

Preoperative maximal coronal Cobb angle improved from 35.0° to 18.0° postoperatively (P <0.0001). SVA decreased from 62.9 mm to 28.6 mm (P <0.0001). ODI improved from 21.1 to 13.6 and NRS decreased from 6.1 to 2.3 at 9-12 months (both P <0.0001). Coronal correction did not correlate with increased rates of dural tears or blood loss >2500 mL. Reoperation rate due to hardware-related complications was 9.3%.

Significant improvements in coronal and sagittal alignment were observed following surgery incorporating PSRs, along with reductions in disability and pain. These findings demonstrate adequate coronal correction while maintaining sagittal alignment; however, causality cannot be inferred in this retrospective series.