Pulmonary Function at Minimum 10 Years After Segmental Pedicle Screw Instrumentation for Thoracic Adolescent Idiopathic Scoliosis.

A prospective multi-center cohort study.This study evaluates the 10-year pulmonary function outcomes for patients with structural thoracic adolescent idiopathic scoliosis (Lenke curve types 1-4, 6) after segmental pedicle screw instrumentation.Adolescent idiopathic scoliosis with thoracic curves is associated with reduced pulmonary function preoperatively. It remains unclear how much pulmonary improvement can be obtained using pedicle screw instrumentation at long-term follow-up.Out of 64 consecutively surgically treated patients with thoracic AIS (Lenke 1-4, 6) using pedicle screw instrumentation, 50 (mean age at final FU 14.7 ± 1.9, 44 females) participated in a prospective 10-year follow-up study. They were evaluated using clinical examination, spinal radiographs, and spirometry preoperatively and at 10-year follow-up. The preoperative percentage predicted values were adjusted for the height loss caused by the scoliosis according to curve size.Preoperatively 49% (20/41) had forced vital capacity (FVC) or forced expiratory volume in one second (FEV1) below 80% of the predicted normal values representing pulmonary function impairment. Major curve correction averaged 76% (SD 9%). FVC improved from preoperative 3.29 L (SD 0.78L) to 3.87 L (0.79L) at 10-year follow-up (P<0.001). This improvement averaged 510 mL (SD 560 mL) in patients having both preoperative and 10-year follow-up measurements available. The percentage predicted values for FVC showed an improvement from 83% preoperatively to 86% at 10-year follow-up (P=0.048). At 10-year follow-up 38% (19/50) of the patients had FVC or FEV1 below 80% of the predicted values.FVC improved by a mean of 510 ml from preoperative to 10-year follow-up in patients undergoing pedicle screw instrumentation for thoracic AIS. Despite 76% scoliosis correction and significant improvement of absolute lung volume values, more than one-third of these surgically treated otherwise healthy young adults fulfilled the criteria for pulmonary function impairment at 10-year follow-up.II.