Changes in thoracic spinal curvature after nuss procedure in adult pectus excavatum

BACKGROUND: Pectus excavatum (PE) is commonly associated with spinal abnormalities. However, the effect of the Nuss procedure on thoracic scoliosis remains unclear. This study therefore aimed to characterize the dynamic changes in the thoracic Cobb angle (tCA) among adult PE patients undergoing Nuss procedure. METHODS: A total of 186 Patients with PE who underwent the Nuss procedure and subsequent bar removal (BR) were retrospectively analyzed. Clinical data were collected, including serial tCA measurements from posteroanterior chest radiographs taken preoperatively, at 1 month, 3-6 months, and 1 year postoperatively, as well as 1 day before and 1 week after BR for analysis. Subgroups were stratified by sex, Haller index (≥ 4 vs. <4), bar number (1-3), bar orientation (oblique vs. horizontal), bar flipping within 3 months, and preoperative tCA (≥ 10° vs. <10°). RESULTS: Compared to the preoperative mean tCA, the tCA increased significantly at 1 month postoperatively (5.4 ± 4.2° vs. 5.9 ± 4.4°, p < 0.001). It then decreased significantly by 1 day before BR (5.4 ± 4.2° vs. 4.9 ± 3.9°, p < 0.001) and further at 1 week after BR (5.4 ± 4.2° vs. 4.4 ± 4.0°, p < 0.001). All subgroup analyses demonstrated a significant reduction in the tCA following BR. CONCLUSIONS: The Nuss procedure induced a temporary increase in tCA at 1 month postoperatively, followed by gradual improvement during the bar maintenance period and a net reduction below the preoperative level after bar removal. Notably, patients with mild thoracic scoliosis also experienced a reduction in tCA after complete PE correction. While this reduction was not clinically meaningful, it still indicates that the procedure does not worsen thoracic spinal alignment and may offer some improvement.