Does pulmonary function improve after surgical correction of adult idiopathic scoliosis?

Purpose The aim was to investigate pulmonary function after surgical correction of adult idiopathic scoliosis. Methods This study included 146 adult scoliosis patients aged 20–50 years (main curve in thoracic spine). Respiratory function was assessed as predicted forced vital capacity (%FVC) and the ratio of forced expiratory volume in 1 s / FVC (%FEV 1 ) preoperatively and 2 years postoperatively and classified as a normal function (≥ 80%), mild impairment (≥ 65% and < 80%), and moderate impairment (< 65%). Results Preoperative %FVC and %FEV 1 were 85.3% and 85.4%, which were 81.5% and 87.5% at 2 years post-surgery. The preoperative %FVC was mild and moderate in 39 (26.7%) and 12 patients (11.6%), respectively. The %FVC significantly improved (+ 6.2% ± 11.4%, P < 0.001) postoperatively for moderate severity but significantly decreased postoperatively (− 6.4% ± 9.4%, P < 0.001) for normal function. The preoperative %FEV 1 was mild and moderate in 27 (18.5%) and 0 patients, respectively. The %FEV1 significantly improved postoperatively (6.3% ± 5.3%, P < 0.001) for mild severity but did not significantly change for normal severity. Twenty-three (15.8%) and 41 (28.1%) patients showed improved ⊿%FVC and ⊿% FEV 1 > 5%. Logistic regression analysis showed that preoperative %FVC and %FEV 1 severities were independent factors affecting postoperative recovery of %FVC (OR 0.95) and %FEV 1 (OR 0.85). Conclusion Pulmonary function improved in patients with preoperative pulmonary impairment of < 65% in %FVC and < 80% in %FEV 1 , and the real improvement was limited to patients with severe preoperative impairment.