THE IMPACTS OF INSTRUMENTED POSTERIOR FUSION SURGERY ON PULMONARY VOLUME AND FUNCTION IN ADOLESCENTS IDIOPATHIC SCOLIOSIS

Objective: There is conflicting evidence regarding the effect of spinal deformity correction on pulmonary function in adolescent idiopathic scoliosis (AIS). Materials and Methods: This study evaluated postoperative pulmonary function and capacity in AIS patients undergoing instrumented posterior fusion. Pulmonary parameters assessed included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), total lung capacity (TLC), residual volume (RV), and the RV/TLC ratio. Postoperative results were compared with predicted values from a healthy community cohort. Subgroup analyses based on Cobb angle, age, and gender were also conducted. Results: Instrumented posterior fusion surgery led to significant changes in TLC (p=0.000) and RV (p=0.014), with increased lung volumes postoperatively. However, there were no significant changes in the FEV1 and FVC ratios compared to predicted values (p=0.070 and p=0.142, respectively). When categorized by age, significant differences in FEV1 were observed in patients aged >16 years (p=0.037). Despite increased lung volumes, no significant impact on functional pulmonary capacity was found during the two-year follow-up. Conclusion: Instrumented posterior fusion surgery increases lung volumes, such as TLC and RV, in AIS. However, these volume changes do not result in significant improvements in functional pulmonary capacity, like FVC and FEV1. This suggests that while the surgery may relieve some mechanical constraints, it does not fully restore pulmonary function. The limited functional recovery may be due to incomplete alveolar maturation during childhood. Further research is needed to explore the relationship between spinal deformities and pulmonary function, focusing on genetic and histological factors.