Haptic Interface for the Simulation of Endovascular Interventions

Endovascular interventions are minimally invasive surgical procedures that are performed to diagnose and treat vascular diseases. These interventions use a combination of long and flexible instruments known as guidewire and catheter. A popular method of developing the skills required to manipulate the instruments successfully is through the use of virtual reality (VR) simulators. However, the interfaces of current VR simulators have several shortcomings due to limitations in the instrument tracking and haptic feedback systems design. A major challenge of developing physics-based training simulations of endovascular interventional procedures is to unobtrusively access the central, co-axial guidewire for tracking and haptics. This work sets out to explore the state of the art, to identify and develop novel solutions to this concentric occlusion problem, and to perform a validation of a proof of concept prototype. This multi port haptic interface prototype has been integrated with a 3-D virtual environment and features novel instrument tracking and haptic feedback actuation systems. The former involves the use of an optical sensor to detect guidewire movements through a clear catheter, whereas the latter utilises the placement of a customised electromagnetic actuator within the catheter hub. During the proof of concept validation process, both systems received positive reviews. Whilst the haptic interface prototype designed in this work has met the original objectives, there are still important aspects which need to be addressed to improve its content and face validity. With further development, the prototype has the potential to evolve and become a significant improvement over the haptic interfaces that exist today.Open Acces

Virtual Reality Simulation of Liver Biopsy with a Respiratory Component

International audienceThe field of computer-based simulators has grown exponentially in the last few decades, especially in Medicine. Advantages of medical simulators include: (1) provision of a platform where trainees can practice procedures without risk of harm to patients; (2) anatomical fidelity; (3) the ability to train in an environment wherein physiological behaviour is observed, something that is not permitted where in-vitro phantoms are used; (4) flexibility regarding anatomical and pathological variation of test cases that is valuable in the acquisition of experience; (5) quantification of metrics relating to task performance that can be used to monitor trainee performance throughout the learning curve; and (6) cost effectiveness. In this chapter, we will focus on the current state of the art of medical simulators, the relevant parameters required to design a medical simulator, the basic framework of the simulator, methods to produce a computer-based model of patient respiration and finally a description of a simulator for ultrasound guided for liver biopsy. The model that is discussed presents a framework that accurately simulates respiratory motion, allowing for the fine tuning of relevant parameters in order to produce a patient-specific breathing pattern that can then be incorporated into a simulation with real-rime haptic interaction. Thus work was conducted as part CRaIVE collaboration [1], whose aim is to develop simulators specific to interventional radiology

Interventional radiology virtual simulator for liver biopsy

Purpose Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees’ inexperience and the variable exposure to case mix and emergencies during training. To address this, we have developed a computer-based simulation of visceral needle puncture procedures. Methods A real-time framework has been built that includes: segmentation, physically based modelling, haptics rendering, pseudo-ultrasound generation and the concept of a physical mannequin. It is the result of a close collaboration between different universities, involving computer scientists, clinicians, clinical engineers and occupational psychologists. Results The technical implementation of the framework is a robust and real-time simulation environment combining a physical platform and an immersive computerized virtual environment. The face, content and construct validation have been previously assessed, showing the reliability and effectiveness of this framework, as well as its potential for teaching visceral needle puncture. Conclusion A simulator for ultrasound-guided liver biopsy has been developed. It includes functionalities and metrics extracted from cognitive task analysis. This framework can be useful during training, particularly given the known difficulties in gaining significant practice of core skills in patients

New haptic syringe device for virtual angiography training

Angiography is an important minimally invasive diagnostic procedure in endovascular interventions. Effective training for the procedure is expensive, time consuming and resource demanding. Realistic simulation has become a viable solution to addressing such challenges. However, much of previous work has been focused on software issues. In this paper, we present a novel hardware system-an interactive syringe device with haptics as an add-on hardware component to 3D VR angiography training simulator. Connected to a realistic 3D computer simulation environment, the hardware component provides injection haptic feedback effects for medical training. First, we present the design of corresponding novel electronic units consisting of many design modules. Second, we describe a curve fitting method to estimate injection dosage and injection speed of the contrast media based on voltage variation between the potentiometer to increase the realism of the simulated training. A stepper motor control method is developed to imitate the coronary pressure for force feedback of syringe. Experimental results show that the validity and feasibility of the new haptic syringe device for achieving good diffusion effects of contrast media in the simulation system. A user study experiment with medical doctors to assess the efficacy and realism of proposed simulator shows good outcomes

A Robotic Platform for Endovascular Aneurysm Repair

International audienceAn EndoVascular Aneurysm Repair (EVAR) isa procedure used to fix an aneurysm of the aorta. In thisprocedure, a guide is inserted by the femoral artery. This guidegoes through to the height of the aneurysm and then a catheterfollows the guide. Next, a stent graft is deployed in order torepair the aortic aneurysm. The objectives of our work is todevelop a low-cost robotic system and implement a programthat helps the trajectory planning during an endovascularoperation. More precisely, this program can predict if the aortawill break or not depending on the guide used. Such a roboticplatform could serve as a teaching instrument by creating anenvironment for young surgeons in which they will be able topractice their skills to perform an EVAR. This paper describesthe different components of this platform and provides someexperimental results