Changes in thoracic Cobb angle dynamics following Nuss procedure and bar removal in adult patients with pectus excavatum

Background Pectus excavatum is associated with spinal abnormalities. The Nuss procedure is the standard surgical correction approach, though its effect on spinal alignment, especially the thoracic Cobb angle, remains unclear. This study examined changes in thoracic Cobb angle dynamics in 109 adult patients with pectus excavatum. Methods Patients with pectus excavatum (109; 86 males and 23 females; mean age: 23.9 ± 5.29 years) who underwent the Nuss procedure and subsequent bar removal were retrospectively analyzed. Demographic and clinical data were collected, including serial thoracic Cobb angle measurements from posteroanterior chest radiographs preoperatively, 1 month, 3–6 months, and 1 year postoperatively, 1 day pre-bar removal, and 1 week post-bar removal. Subgroup analyses were stratified by sex, Haller index (≥ or <4), bar number (1, 2, or 3) and position (oblique vs. horizontal), bar flipping within 3 months, and preoperative Cobb angle (< or ≥10°). Results Mean thoracic Cobb angle significantly increased 1 month postoperatively (preoperative: 5.35±4.80° vs. 1 month postoperative: 5.75±5.00°, P=0.004), but significantly decreased 1 day before bar removal (preoperative: 5.35±4.80° vs. 1 day pre-bar removal: 4.90±4.74°, P=0.006) and 1 week after (preoperative: 5.35±4.80° vs. 1 week post-bar removal: 4.26±4.72°, P<0.001). Cobb angle significantly improved after bar removal. Conclusions In adult patients with pectus excavatum, the Nuss procedure induced a transient increase in thoracic Cobb angle 1 month postoperatively, followed by a significant reduction after bar removal. Early bar flipping correlated with diminished Cobb angle correction.