Abstract
PURPOSE: Thoracic hyperkyphosis (THK) is a prevalent spinal deformity in adolescents, which can impair respiratory function by affecting diaphragm morphology and thoracic mechanics. This study investigates the relationship between THK and diaphragmatic thickness using ultrasonography (USG) to explore its diagnostic and therapeutic implications. METHODS: This prospective study included 25 adolescents with THK and 29 healthy controls. Diaphragmatic thickness was measured using ultrasonography at the end of inspiration and expiration, and spirometry was conducted to assess respiratory function. Thoracic hyperkyphosis was diagnosed based on Cobb angle measurements. Statistical analysis included regression and ROC analyses to determine predictors of THK and evaluate diagnostic accuracy. The study was approved by the local Ethics Committee of the University of Healthy Science, Gaziosmanpasa Training and Research Hospital (IRB number: 109, date: 16 August 2023). The study protocol was registered to the clinicaltrial.gov.tr (NCT06418334 and initial release date: 01/11/2024). RESULTS: Adolescents with THK exhibited significantly higher Cobb angles (59.3 ± 7.9°) compared to controls (34.6 ± 3.7°, p < 0.001). Diaphragmatic thickness during inspiration (2.5 mm vs. 3.1 mm, p = 0.125) and expiration (1.50 mm vs. 1.56 mm, p = 0.965) was lower in the THK group, with significant reductions in thickening ratio (1.76 ± 0.29 vs. 1.98 ± 0.30, p = 0.008) and thickening fraction (DTf) (75.4% vs. 97.6%, p = 0.008). A negative correlation was observed between Cobb angle and diaphragmatic thickening (r=-0.378, p = 0.005). ROC analysis indicated that USG parameters, particularly thickening fraction (AUC = 0.72, p = 0.002), are reliable predictors of THK. CONCLUSION: Adolescents with THK demonstrate reduced diaphragmatic thickness and impaired respiratory function. Ultrasonography emerges as a valuable, non-invasive tool for early diagnosis and monitoring of THK, offering potential for timely intervention to mitigate respiratory complications.