Lung function after growing rod surgery for progressive early-onset scoliosis: a preliminary study.

Background: Pulmonary problems often occur in patients with early-onset scoliosis (EOS). However, lung function in patients with EOS after growing rod surgery has not been documented. The aim of this study was to investigate lung function after the treatment for EOS with growing rod and its possible correlative factors.
Methods: Eight patients with EOS were treated with growing rod surgery at Peking Union Medical College Hospital from September 2002 to September 2009. Four patients had finished the final fusion surgery (group 1), and the other 4 (group 2) were in the process of periodic lengthening. Preoperative forced vital capacity (FVC), ratio of FVC to predicted FVC, forced expiratory volume in 1 second (FEV1), ratio of FEV1 to predicted FEV1, and radiographic measurements of Cobb's angle and C7-S1 distance were recorded. Lung function changes and correlations between lung function changes and radiographic changes (Cobb's angle and C7-S1 distance) were analyzed.
Results: In group 1, FVC and FEV1 both increased. FVC showed a significant difference (P = 0.01), but FEV1 did not (P = 0.05). In group 2, FVC and FEV1 also increased, and both showed a significant difference (P = 0.04 and P = 0.02, respectively). Ratio of FVC to predicted FVC and ratio of FEV1 to predicted FEV1 changed similarly and did not show statistical differences in the 2 groups. There were no significant correlations between lung function changes and radiographic changes (Cobb's angle and C7-S1 distance) (P = 0.10 and P = 0.41, respectively).
Conclusions: Lung function increases after growing rod surgery in patients with EOS. Lung function changes do not correlate with Cobb's angle changes or C7-S1 distance changes.