Using Compliant Implants to Reduce Post-Operative Pain in Pectus Excavatum Correction

Abstract

In this work, we propose a medical device to be used for correcting pectus excavatum. Pectus excavatum is the most common chest wall deformity, resulting in exercise intolerance, shortness of breath, and chest pain. The current correction method uses a rigid bar that causes moderate to severe pain in patients. The device presented in this paper (termed the Elastic Bar) utilizes the phenomenon seen in pectus carinatum patients in which the patient’s chest wall becomes less stiff after a force is applied for an extended period of time; the device leverages this phenomenon to create gradual correction of the deformity. The elastic bar is a compliant solution to pectus excavatum. We present a set of requirements that determine the success of the compliant solution to correcting pectus excavatum. To analyze the performance of the device against these requirements, two models are developed, one using a fixed-guided modeling approach and the other using an initially curved beam modeling approach. We then use analytical models (developed following the Pseudo-Rigid-Body modeling technique), finite element analysis simulations, and a physical prototype to verify the feasibility of this new device. We find that the three different verification methods agree within approximately 10%. We conclude that this device has the potential to provide improved care to patients with pectus excavatum.