Study Design. Retrospective review of prospectively-accrued cohorts.Objective. We hypothesized that posterior-only vertebral column resection (PVCR) would result in improved postoperative pulmonary function, avoiding pulmonary insults from combined anterior/posterior (A/P) approaches.Summary of Background Data. Pulmonary function after PVCR for severe spinal deformity has not been previously studied. Previous studies have demonstrated impaired pulmonary performance after combined A/P fusions.Methods. Serial pulmonary function testing (PFTs) in 49 patients (27 pediatric, 22 adult) who underwent PVCR at a single institution were reviewed. Mean age at surgery was 28.7 years (range, 8-74 years), and mean follow-up was 32 months (range, 23-64 months). Thoracic PVCRs (T5-T11) were performed in 31 patients and thoracolumbar PVCRs (T12-L5) in 18 patients.Results. Pediatric PVCR patients experienced both increased mean forced vital capacity (FVC) (2.10 to 2.43L, p = 0.0005) and forced expiratory volume in 1 second (FEV1) (1.71 to 1.98L, p = 0.001). There were no significant differences in percent-predicted values (%PV) for FVC (69% to 66%, p = 0.51) or FEV1 (64% to 63%, p = 0.77). In adult patients, there were no significant changes in FVC (2.73 to 2.61L, p = 0.35) or FEV1 (2.22 to 2.07L, p = 0.51) after PVCR; also, changes in adult%PV for FVC (79% to 76%, p = 0.47) and FEV1 (78% to 74%, p = 0.40) were not significant. In pediatric PVCR patients, improved PFTs were correlated with younger age (p = 0.02), diagnosis of angular kyphosis (p≤0.0001), no previous spine surgery (p = 0.04), and preoperative halo traction (p = 0.02). Comparison of PFT changes between PVCR patients and a control group who underwent combined A/P approaches revealed no significant differences.Conclusion. In pediatric patients, PVCR resulted in small but significant improvements in postoperative FVC and FEV1. In adult patients, no significant increases in PFTs were found. Patients who have the greatest potential for lung and thoracic cage growth after spinal correction are most likely to have improved pulmonary function after PVCR.