Improvement of pulmonary function and reconstructed 3D lung volume after deformity correction for thoracic spinal posttubercular kyphosis: a multicenter study

OBJECTIVE The aim of this study was to investigate the influence of corrective surgery on thoracic spinal posttubercular kyphosis (PTK) with respect to lung volume and pulmonary function. METHODS This was a retrospective study of 126 patients (72 males and 54 females) who underwent posterior vertebral column resection (PVCR) for severe thoracic spinal PTK between September 2013 and June 2020. The patients’ spinal parameters, results of their pulmonary function test (PFT), and CT-based 3D lung volume were recorded and analyzed preoperatively and at final follow-up. The correlation of kyphosis correction with the PFT and lung volume was evaluated. RESULTS The mean local kyphosis decreased from 112.5° to 37.2°, and the mean local scoliosis decreased from 20.9° to 5.2°; C2–7 lordosis, thoracic kyphosis, and lumbar lordosis also significantly improved after surgery. The mean CT-based lung volume significantly increased from 2.9 L preoperatively to 3.6 L at the final follow-up. The indices of PFT, including forced vital capacity (FVC), percent predicted FVC, total lung capacity, and forced expiratory volume in 1 second, were also significantly improved, and 60 patients with pulmonary dysfunction recovered to normal at the final follow-up. The correlation analysis revealed that the correction of local kyphosis was closely correlated with the improvement in PFT and the increase in lung volume. CONCLUSIONS PVCR cannot only effectively realign the spine in patients with severe thoracic spinal PTK deformity but also significantly improve pulmonary function. Adequate local kyphosis correction should be highly valued, as it is a key factor in increasing lung volume.