The Haller index is the current gold standard for defining the severity of Pectus Excavatum. It is calculated by CT scan. At the deepest point of the indent, the width of the chest wall and the depth of the indent is measured. Then, a ratio of the width to the depth is calculated, and gives a value.
- A Haller index of 3.5 is typically needed for insurance purposes to approve surgery
- A Haller index around 3.5 is typically considered a moderate severity
- A Haller index around 5 is typically considered a more severe case
- The most severe Haller index ever reported was a negative value. In other words, the indent was so deep that the sternum (breast bone) went past the spine such that the spine was in front of the chest, not the other way around. This is extremely rare and only one case has been reported.
- In a study of 303 patients, the Haller index ranged from 2 to 21. The average was 5. (See Croitoru et al., 2002).