Associations of Haller index and manual depth measurement with clinical findings and pulmonary function in children with pectus excavatum: a retrospective cross-sectional study

BACKGROUND: Pectus excavatum (PE) is the most common congenital chest wall deformity. Its severity is usually assessed by chest computed tomography (CT) based indices such as the Haller index (HI) and correction index (CI). However, evidence supporting non-imaging anthropometric methods is limited. Manual depth measurement (MDM) is a simple, noninvasive bedside method that may offer clinical value. METHODS: This retrospective cross-sectional study included children diagnosed with pectus excavatum and followed at a tertiary center between 2017 and 2024. Demographics, pulmonary function tests (PFTs), symptoms, comorbidities, and echocardiographic data were analyzed. HI and CI were measured using chest CT scans. MDM values recorded during follow-up were retrieved from physical exam notes. RESULTS: A total of 127 patients were included, with a median age of 7.25 years (IQR, 7.05). Median HI was 2.70 (IQR, 0.56), median MDM was 2.00 cm (IQR, 1.35), and median CI was 16% (IQR, 6.7). MDM was significantly correlated with HI (p = 0.012). ROC analysis showed that MDM moderately but significantly discriminated severe deformity defined as HI> 2.5, with an optimal cut-off value of 1.75 cm. Respiratory symptoms and comorbidities were present in 39.4% and 38.6% of patients, respectively. Pulmonary function impairment was observed in 19% of patients, predominantly with a restrictive pattern. HI> 2.5 was associated with reduced forced vital capacity (FVC) and total lung capacity (TLC), whereas the association between MDM> 1.75 cm and TLC <80% weakened after adjustment for age. CONCLUSION: MDM is a practical bedside measurement that correlates with HI and involves no radiation exposure. An MDM threshold of 1.75 cm was associated with HI> 2.5 in the CT-evaluated subgroup and may support conservative follow-up when interpreted together with clinical and functional findings. This threshold should be considered exploratory and requires prospective validation.