Pulmonary Function Before Surgery for Pectus Excavatum and at Long-term Follow-up: Methods

Pulmonary function measurements consisted of TLC using the helium dilution technique (IVC), residual volume (RV), functional residual capacity (FRC), forced expiratory volume in 1 s (FEVi) and FEVi/IVC (Pulmonet III wet spirometer, Sensor-medics, Bilthoven, the Netherlands). Values were expressed in percent predicted values in accordance with Zapletal et al for children and the European Respiratory Society for adults. The measurements were performed twice: 3 days before the operation and during the visit to the outpatients department for the purpose of this study.
The presence of sternal depression and the degree of depression were evaluated from the lateral chest radiographs (Fig 1). We used a modification of the vertebral index, described previously, to classify the patients. At the level of the xiphosternal junction, a line was drawn perpendicular to the vertebral body and the lower vertebral index (LVI) was calculated by dividing the vertebral body diameter at that level by the distance between the xiphosternal junction and the posterior border of the vertebral body. Derveaux et al measured the LVI in a group of 250 healthy individuals and found that it was age dependent there canadian drug mall. Predicted values for the various age groups can be calculated using the formula 0.193 (1—0.326Xe“° 258Xage). Age-corrected deviations from normal (5LVI) were calculated by dividing the difference between the measured LVI and the predicted LVI for a particular age by the standard deviation of the predicted value at that age. A positive value meant that the LVI was higher than normal and thus the posteroanterior diameter was smaller than normal.
The operation consisted of subperichondral chondrectomy of all deformed rib cartilages, transverse sternotomy and division of the intercostal bundles at the outer limit of the chondrectomy, and suturing the edge of this broad sheet of muscle and perichondrium to the anterior surface of the chest wall more laterally and under tension, thus elevating and stabilizing the sternum. This technique avoided the use of internal support or external traction and remained unchanged during the study period.


Figure 1. Left, Lateral chest radiograph of a 17-year-old male patient with severe pectus excavatum (type 3). Complaints of dyspnea on exertion, exercise intolerance, and palpitations had developed over the course of a few years. The anteroposterior diameter was greatly diminished. Pulmonary function was restricted (TLC, 5,800 ml, 72 percent of predicted; IVC, 3,550 ml, 57 percent of predicted; FEVi VC, 73 percent, 88 percent of predicted). Right, Lateral chest radiographs of the same patient at 7 years’ follow-up. The anteroposterior diameter was markedly increased and the sternum was fairly straight. Surgical result was excellent without any physical complaints despite an increase in restriction of pulmonary function (TLC, 5,500 ml, 62 percent of predicted; IVC, 3,500 ml, 51 percent of predicted; FEVi/VC, 90 percent, 107 percent of predicted).

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