Accurate models of the mitral valve are highly valuable for studying the physiology of the heart and its various pathologies, as well as creating physical replicas for cardiac surgery training. Currently, heart simulator technologies are used which rely on patient-specific data to create valve replicas. Alternatively, mathematical models of the mitral valve have been developed for computational applications. However, there are no studies that mathematically model both the mitral valve’s leaflets and its saddle-shaped annulus in a single design together in current literature. This results in anatomic inaccuracies in current models, as either only the leaflets or the saddle-shaped annulus are realistically modelled. Mathematical models to date have not been replicated as dynamic, physical valves and validated in a heart simulator system. We propose a new parametric representation of the mitral valve based on a combination of valve models from prior literature, combining both accurate leaflet shape, and annular geometry. A physical silicone replica of the model is created and validated in a pulse duplicator. Using a transesophageal echocardiography probe with color Doppler imaging, we demonstrate that our combined model replicates healthy valve behaviour, showing no regurgitation at realistic pressure gradients across the valve.
PURPOSE: Endoscopic vessel harvesting is the preferred minimally invasive approach to obtain grafts for coronary bypass surgeries, however it requires extensive practice to minimize vessel damage. We propose to create a surgical training simulation with visual and haptic feedback. In this study, we focus on analyzing the force and torque peaks on the surgical retractor during the procedure. METHODS: The original retractor handle was 3D scanned and modified to attach an ATI Mini40 force-torque transducer. The forces and torques in two radial artery and two saphenous vein procedures in human cadavers were recorded. The measurements, endoscopic video and surgical surface video were collected. The median and interquartile range of the force and torque peaks were calculated for the artery and vein harvesting procedures. RESULTS: The median and interquartile range for saphenous vein harvests was larger than radial artery harvests. The largest median force and torque generated in the vein was 11.654 N [posterior] and 0.661 Nm [- frontal], whereas in the artery was 6.163 N [anterior] and 0.381 Nm [+ frontal], respectively. CONCLUSION: The distribution of force and torque peaks in the retractor was found for endoscopic vessel harvests. This data can be used to design a haptic user interface, and to establish expert benchmarks for learning curve evaluation.
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