It's not about the dent: Anteroposterior insufficiency in pectus excavatum

Pectus Excavatum (PEx) is an anterior chest wall deformity associated with sternal depression. Minimal invasive repair of PEx (MIRPE) and open pectus repair depend on anterior ribs to elevate the sternal defect. Many PEx patients, however, have inadequate anteroposterior (AP) distance to support a complete repair. The quantity and frequency of AP insufficiency (API) in a PEx surgical population is reported.

A retrospective analysis of 100 pectus excavatum (PEx) patients with a CT or MRI Haller Index >3.2 was performed. Demographics, Haller Index (HI), Correction Index (CI), and maximum AP distances (APmax) from a line level with the spine to the highest anterior rib (pectus ridge) were measured. Predicted APmax = 40% the transverse diameter based on prior studies. The quantity of API was defined as the predicted APmax - actual APmax.

Median age was 15.2 years; 62% male. The median HI was 4.8, and CI was 32%. PEx patients had a median APmax of only 78% predicted [IQR 70, 84]. The median absolute lack of AP distance in PEx patients was 2.2 cm [IQR 1.4,2.9].

Inadequate AP distance is common in patients with PEx. Pectus repair that elevates the sternum only to the level of the pectus ridge would fail to normalize the AP distance in most patients, despite correction of the visible indentation. Technical corrections with convex bars lifting the ribs and sternum above the pectus ridge are necessary to normalize the AP distance and relieve cardiac compression in patients with API.