Automatic Prebent Customized Prosthesis for Pectus Excavatum Minimally Invasive Surgery Correction

Abstract

Pectus excavatum is the most common deformity of the thorax. A minimally invasive surgical correction is commonly carried out to remodel the anterior chest wall by using an intrathoracic convex prosthesis in the substernal position. The process of prosthesis modeling and bending still remains an area of improvement. The authors developed a new system, i3DExcavatum, which can automatically model and bend the bar preoperatively based on a thoracic CT scan. This article presents a comparison between automatic and manual bending. The i3DExcavatum was used to personalize prostheses for 41 patients who underwent pectus excavatum surgical correction between 2007 and 2012. Regarding the anatomical variations, the soft-tissue thicknesses external to the ribs show that both symmetric and asymmetric patients always have asymmetric variations, by comparing the patients' sides. It highlighted that the prosthesis bar should be modeled according to each patient's rib positions and dimensions. The average differences between the skin and costal line curvature lengths were 84 ± 4 mm and 96 ± 11 mm, for male and female patients, respectively. On the other hand, the i3DExcavatum ensured a smooth curvature of the surgical prosthesis and was capable of predicting and simulating a virtual shape and size of the bar for asymmetric and symmetric patients. In conclusion, the i3DExcavatum allows preoperative personalization according to the thoracic morphology of each patient. It reduces surgery time and minimizes the margin error introduced by the manually bent bar, which only uses a template that copies the chest wall curvature.

Patient-specific outcome simulation after surgical correction of Pectus Excavatum: a preliminary study

“…The personalized bar was modeled with the system developed by Vilaça et al 32 using the CT data of each patient. The bar shape and size were used to bend the metal bar applied in the surgery and to create the virtual model of the bar used in the FEM simulation.…”

The Role of Three-Dimensional Printing in the Nuss Procedure: Three-Dimensional Printed Model-Assisted Nuss Procedure

“…Traditionally, the length of the pectus bar is determined by measuring the distance between the midaxillary lines with a measuring tape and subtracting 2.5 cm [1]. Although the Nuss procedure has become the standard for surgical PE intervention [2], the size and curvature of the pectus bar are determined by trial and error with repeated insertions and flips of the pectus bar [3][4][5]. These readjustments are bothersome and potentially hazardous.…”

“…The Nuss procedure, first reported in 1998 by Nuss and associates [1], is the placement of a pectus bar to elevate the sternum anteriorly. Although the Nuss procedure has become the standard of surgical intervention for PE [2], the size and curvature of the pectus bar is determined by trial and error by repeated insertion and flipping of the pectus bar [3][4][5].…”

Chest Modeling and Personalized Surgical Planning for Pectus Excavatum

“…However, it has been shown that the conventional pectus bar modeling based on the patient's skin profile is imprecise [4]. More recently, the same group evaluated a system simulating the pectus bar, but the design of the bar was not presented [5]. Wei et al developed a biomechanical model of PE based on a finite element model using a single patient CT image [6], but the rib cage used to establish the model was manually segmented.…”