Developing an anatomical simulator for early stage usability testing of endovascular devices

Adverse medical events resulting in serious harm occur in approx. 1-4% of all hospital admissions (Sarker and Vincent 2005). Endovascular devices encompasses a wide range of medical devices designed to treat diseases using a minimally invasive approach. These devices range from coronary stents to full aortic valve replacement and are delivered through the vascular system. Usability engineering is a sub specialty of ergonomics concerned with the development of devices that are fit for use (Kramme et al. 2011). Usability Testing (UT) of medical devices is an integral part of the regulatory requirements for device approval in both the United States and the European Union. UT champions the use of simulated use testing, particularly at the early stage and validation stage of the design process (FDA 2011). Simulated UT is a safe and ethical way of eliciting user needs, testing device prototypes, and validating design solutions in order to reduce the likelihood of an adverse event occurring. During UT, there is an onus on the tester to provide operators with a sufficient level of fidelity so as to cause a ‘suspension of disbelief’ during the task (Halamek et al. 2000); that is, that the operator thinks and feels like they are performing in the real environment. Currently, UT of endovascular medical devices is undertaken in pulsatile flow rigs with hollow silicone anatomical models and direct visualisation of devices in the model. There are several limitations with the use of these models such as the lack of anatomical realism, manufacturing methods and portability. These omissions can negatively impact the reaction of endovascular devices in the models, resulting in flawed test results. The aim of the current research was to develop an anatomical simulator for early stage usability testing of endovascular devices. A protocol was developed to digitally segment compound anatomical models that include all structures encountered in clinical practice such as thrombus and calcifications. These digital models were modified to include standardised mounts for the usability test bed. New methods of physically reproducing compound models using multi material 3D printing were explored, as the use of the lost wax casting method is inappropriate for these complex models. The 3D printed compound anatomical models were integrated into a newly developed portable pulsatile flow simulator. The simulator includes real time haemodynamic monitoring and a simulated fluoroscopy imaging system. The 3D printed compound anatomical models were integrated into a newly developed portable pulsatile flow simulator. The simulator includes real time haemodynamic monitoring and a simulated fluoroscopy imaging system.