Background: Measurements in chest wall deformities are typically conducted using a thorax caliper or a CT scan of the chest wall. This paper focuses on the possible correlation between these two methods to validate the reliability of the thorax caliper, minimize radiation exposure, and limit the usage of expensive imaging techniques.
Methods: We evaluated 95 consecutive patients (77 pectus excavatum (PE), 17 pectus carinatum (PC), 1 mixed deformity) who received surgical correction of the anterior chest wall. The results of the external chest wall measurements and the CT-based measurements were statistically compared.
Results: A significant correlation between the two measurements was observed in PE and PC at the highest point of the deformation. The strongest correlation was noted in PE. We also noted a correlation between the transverse diameter of the external measurement and the inner thoracic diameter of the CT scan but not for the sagittal diameters in the upper parts of the sternum.
Conclusions: Thorax caliper measurements are suitable for determining the sagittal thoracic diameter at the maximum level of the deformity and the transverse diameter with an accuracy comparable to that of CT measurements. Since these values key, the thorax caliper is reliable for monitoring and documenting chest wall malformations.
Level of evidence: Study of diagnostic test. Testing previously developed diagnostic criteria in a consecutive series of patients and a universally "gold" standard-Level I.
Keywords: External measurements; Haller index; Pectus carinatum; Pectus deformity; Pectus excavatum.
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