Taulinoplasty: the traction technique—a new extrathoracic repair for pectus excavatum

The most frequent deformity of the ribcage is pectus excavatum (PE), which is described as the sternum sinking into the mediastinum. It is most likely caused by a congenital abnormality of the cartilage of the costosternal joints. PE becomes apparent at the age of lactation, and in severe cases, can persist into adulthood. The associated symptoms depend on the severity of the deformity. Symptomatic patients with alterations in the complementary explorations are candidates for surgery. Until the 1990s, the standard surgical treatment consisted of a subperichondral resection of the affected costosternal joints, with stabilization using an internal osteosynthesis of the fractures produced for the reduction of the defect. In 1998, Donald Nuss published his non-invasive technique for lifting the sunken chest (1). Dr. Nuss’ technique achieved the reduction of sternal collapse by rotating the pectus bar, based on the physical principle of levers which states that any weight can be lifted by a fulcrum and a long enough lever arm. Open surgical procedures were shifted, with some exceptions only, by the introduction of the Nuss minimally invasive thoracoplasty (MIRPE), due to its excellent outcomes and the effectiveness of the bloodless reduction of the sternum achieved by levering from inside the chest. Inspired by the same principles as in the Nuss Procedure, we thought that sternal lifting could also be possible through external traction, in order avoid invading the mediastinum or pleural cavity. For this purpose, a plate for extrathoracic implantation and an associated traction system were designed. The plate has a specific shape and size to support and distribute the necessary loads over the defect. The traction system was designed to withstand the loads to be counteracted in the reduction of the sunken chest. The pectus plate and traction system are shown in detail in the video. The forces required for the reduction of PE have been well studied by Fonkalsrud and Weber (2,3). It seems clear that in adult patients with a Haller Index of 5 or more, the force needed to counteract the resistance of the sunken chest should be over 25 kg. For this reason, a series of in vitro tests on porcine sternums were made in order to determine the best configurations of screws according to the traction force required. The effect of a single standard 6.5 mm screw and a combination of two screws was calculated. Finally, a single 8 mm screw was constructed for evaluation. A MTS Bionics 858 high precision machine was used to measure the failure values (i.e., the force at which the traction of the screw breaks the bone). The results of the analysis are given in Newtons (mean and standard deviation). 6.5 mm screw (390.8±82.9N); 2 mm × 6.5 mm screw (1011.9±115.7N) (P≤0.01); 8 mm screw (568.8 ± 113.9N) (P≤0.01). The traction system consists of a screw and nut that are tightened progressively on the pectus plate until the reduction of the defect is achieved. The video shows the traction system reducing the sunken chest. The aim of this article is to describe a non-invasive external traction system that reduces the sunken chest as additional aid in MIRPE, as well as an extrathoracic repair technique for PE.