Does the modelling of the pectus bar affect its stability? Rationale for using a short flat bar.

OBJECTIVES: Although the Nuss procedure for pectus excavatum is still associated with a non-negligible risk of postoperative bar displacement, the potential effects of the length and shape of the bar on its corrective ability and stability have not been sufficiently studied. The aim of this study was to determine how the modelling of the pectus bar affects its stability and whether an alternative configuration of the implant can improve clinical success. METHODS: Simulated implantation of bars with different shapes and sizes in a computational model was carried out. A 250 N sternal force was applied to the bars, and the resulting forces and moments on the fixation points were identified. Afterwards, a clinical trial was carried out in a group of patients with pectus excavatum, some of whom received long inverted U-shaped bars and some of whom received implants designed from the computational results. RESULTS: When U-shaped bars were tested, the sternal force generated unbalanced horizontal reaction forces (16 vs 61 N) and large reaction moments at the ends of the bar, conferring the tendency to slide and to rotate, respectively. No lateral or rotational destabilizing forces occurred in the case of a flat bar. Cosmetic outcomes, postoperative times and hospital stays were similar in both clinical groups. However, 2 cases (2/15) of bar flipping occurred in patients who received the conventional bar. CONCLUSIONS: The shape of the bar is a determinant of its stability. A flat, shorter pectus bar provides adequate correction of the deformity with less tendency for bar displacement in the repair of pectus excavatum.

Selective packing for uncontrollable traumatic thoracic wall bleeding preserving cardiopulmonary function.

BACKGROUND: Uncontrollable chest wall bleeding secondary to thoracic trauma has been a challenging problem faced by surgeons. Thoracic packing has been described as a good alternative although most thoracic surgeons avoid it because of the potential deleterious effects on cardiopulmonary function. METHODS: We describe a selective gauze packing technique of the thoracic wall preserving cardiopulmonary function in 3 patients with uncontrollable bleeding, where gauze packs were placed on bleeding areas holding them in a "sandwich-like" arrangement between the skin and the pleura and tightly fixed with coated wire stitches using internal and external-thoracic Ventrofil® devices. RESULTS: Successful hemostasis and cardio-respiratory stability were achieved in all cases after selective packing. X-ray showed acceptable lung expansion and no heart compression. CONCLUSIONS: This selective packing technique is simple, feasible and highly effective in managing uncontrollable post-traumatic or even post-operative chest wall hemorrhages when the life of patients is in danger.