Use of a novel maximum protrusion index to describe severe pectus carinatum

The absence of standardized criteria for grading pectus carinatum (PC) severity hampers clinical decision-making and insurance approvals. Although the Haller Index (HI) is frequently used, it underestimates deformity by measuring the distance to the posterior sternum rather than the point of maximal protrusion. This study introduces the Maximum Protrusion Index (MPI), a novel metric designed to more accurately reflect PC severity.