A novel measure for pectus excavatum: the correction index

Objective

The Haller Index (HI), the standard metric for the severity of pectus excavatum, is dependent on width and does not assess the depth of the defect. Therefore, we performed a diagnostic analysis to assess the ability of HI to separate patients with pectus excavatum from healthy controls compared to a novel index.

Methods

After institutional review board approval, computed tomography scans were evaluated from patients who have undergone pectus excavatum repair and controls. The correction index (CI) used the minimum distance between posterior sternum and anterior spine and the maximum distance between anterior spine most anterior portion of the chest. The difference between the two is divided by the latter (×100) to give the percentage of chest depth the defect represents.

Results

There were 220 controls and 252 patients with pectus. Mean HI was 2.35, and the mean CI was 0.92 for the controls. The mean HI was 4.06, and the mean CI was 31.75 in the patients with pectus. In the patients with pectus, HI demonstrated a 47.8% overlap with the controls, while there was no overlap for CI.

Conclusions

The Haller index demonstrates 48% overlap between normal patients and those with pectus excavatum. However, the proposed correction index perfectly separates the normal and diseased populations.