Study and quantitative characterisation of 3D printed costal cartilages for highly realistic clinical simulators

Purpose This study aims to improve the mechanical behaviour and aesthetic realism of costal cartilages (CCs) in clinical simulators. Current mannequin components use thermoplastic polyurethane (TPU) with reduced infill, which inadequately replicates the anisotropic mechanical properties and anatomical appearance of actual CCs. An alternative approach was therefore developed to address these limitations. Design/methodology/approach Following a comprehensive literature review, human CCs were characterised geometrically and mechanically. A parametric model for three-dimensional printing was developed, comprising a helical load-bearing structure with an elliptical core encased in a silicone matrix. Variables including aspect ratio, wire diameter and pitch were parametrised. Eighteen configurations were analysed through finite element analysis under tensile and flexural loading. The optimal configuration was validated experimentally on acrylonitrile butadiene styrene-printed specimens. Findings The optimised configuration demonstrated good agreement with human CC reference values. Complete silicone-encased specimens exhibited displacements of 4.8–5.1 mm axially, 3.8–4.1 mm cranio-caudally and 7.2–7.8 mm dorso-ventrally under standard loading. The anisotropic flexural behaviour characteristic of actual cartilage was successfully replicated, with dorso-ventral compliance approximately double that of the cranio-caudal direction. Originality/value This work presents the first parametric, dual-component model specifically designed for CC simulation in surgical training. Unlike existing approaches using uniform TPU or expensive polyetheretherketone prosthetics, the helical structure with an elliptical core achieves anisotropic mechanical behaviour cost-effectively. Systematic characterisation of parameter–property relationships provides design rules enabling customisation. The combination of load-bearing structure and aesthetic matrix addresses both functional and visual realism. This paper presents a proof-of-concept mechanical characterisation and forms the first step of a broader translational programme aimed at integrating the component into high-fidelity thoracic surgical simulators. The combination of load-bearing structure and aesthetic matrix established a methodology applicable to biomimetic modelling of other composite soft tissues.