Background/purpose: Patient reports of preoperative exercise intolerance and improvement after surgical repair of pectus excavatum (Pex) have been documented but not substantiated in laboratory studies. This may be because no study has been large enough to determine if pulmonary function tests (PFTs) in the Pex population are significantly different from the normal population, and none has assessed improvement in pulmonary function after Nuss bar removal.
Methods: The authors studied PFT results in 408 Pex patients before repair and in a subset of 45 patients after Nuss procedure and bar removal. Significance of differences in percent predicted (using Knudson's equations) was tested using t tests (parametric) or sign tests (nonparametric). Normal was defined as 100% of predicted for forced vital capacity (FVC), forced expired volume in 1 second (FEV1), and forced expiratory flow (FEF25%-75%).
Results: Preoperatively, FVC and FEV1 medians were lower than the normal by 13%, whereas the FEF 25-75 median was lower than normal by 20% (all P < .01). The postoperative group had statistically significant improvement after surgery for all parameters. Patients older than 11 years at the time of surgery had lower preoperative values and larger mean post-bar removal improvement than the younger patients. An older patient with a preoperative FEF25-75 score of 80% of normal would be predicted by these data to have a postoperative FEF25-75 of 97%, indicating almost complete normalization for this function.
Conclusions: These results demonstrate that preoperatively Pex patients as a group have decreased lung function relative to normal patients. After Nuss procedure and bar removal, we show a small but significant improvement in pulmonary function. These results are consistent with patient reports of clinical improvement and indicate the need for more in-depth tests of cardiopulmonary function under exercise conditions to elucidate the mechanism.