Changes in chest wall motion with removal of Nuss bar in repaired pectus excavatum - a cohort study

BACKGROUND: The effects of the Nuss procedure on chest wall motion and spirometry have previously been described; we aimed to describe the effects of removal of the Nuss bar.

METHODS: We studied 9 patients just prior to and 6 weeks after Nuss bar removal. Regional chest volume changes, synchrony of respiratory movement and spirometry were recorded using optoelectronic plethysmography (OEP) and compared. Recordings were performed at rest and exercise during cycle ergometry.

RESULTS: There were small but statistically significant changes in tidal volumes of the diaphragmatic ribcage compartment during exercise (+ 48 ml, p = 0.038, Cohen's d = 0.12) and percentage contribution of the diaphragmatic ribcage to total tidal volumes at rest (+ 2.7 percentage points, p = 0.038, Cohen's d = 0.12). Synchrony of respiratory movements at rest and during exercise was unchanged following Nuss bar removal. There were no significant changes in spirometry and exercise capacity.

CONCLUSIONS: The effects of Nuss bar removal on diaphragmatic ribcage motion are detectable but small and unlikely to be of clinical significance. No change in exercise capacity should be expected after Nuss bar removal.

TRIAL REGISTRATION: Registered at ClinicalTrials.gov, identifier NCT02958683 , registered 5th August 2016, first patient enrolled July 2016, retrospectively registered.