Novel low-cost soft-tissue mannequins for medical education

Abstract

Medical simulators are used to help healthcare practitioners learn and refine skills that can only come with sustained experience and practice. However, many training mannequins currently do not simulate the feel of living tissue with sufficient fidelity. This is a drawback when a diagnosis is made through palpation, as in case of the clinical breast exam (CBE), which is in many resource-limited settings the first and only screening method available. Here we describe a novel method for generating medical simulators which are low-cost and more closely resemble living tissue. Using commercially available silicone, a breast model was generated. The apparent stiffness was reduced by introducing voids throughout the interior of the model using the lost-wax method.  Finite element modeling (FEM) was used to predict the effects of size and distribution of voids on the apparent stiffness of the prototypes. The prototypes generated through this process were evaluated by physicians trained in the CBE. Our results show that removal of interior volumes produced softer, more pliant and therefore more life-like models when compared to commercially available devices. This was supported by FEM as well as provider assessment of the physical analogues. We conclude that reducing the apparent stiffness by introducing voids produced simulators which better approximated the mechanical properties of live breast tissue and improved the feel of the simulator. This application of FEM offers an effective tool for low-cost and rapid prototyping, reducing cost and increasing availability in low-resource countries. This approach has the potential to improve medical education by offering a new method for modeling not only breast, but any soft tissue.