Validation of NOViSE.

The goal of this study was to establish face, content, and construct validity of NOViSE-the first force-feedback enabled virtual reality (VR) simulator for natural orifice transluminal endoscopic surgery (NOTES). Fourteen surgeons and surgical trainees performed 3 simulated hybrid transgastric cholecystectomies using a flexible endoscope on NOViSE. Four of them were classified as "NOTES experts" who had independently performed 10 or more simulated or human NOTES procedures. Seven participants were classified as "Novices" and 3 as "Gastroenterologists" with no or minimal NOTES experience. A standardized 5-point Likert-type scale questionnaire was administered to assess the face and content validity. NOViSE showed good overall face and content validity. In 14 out of 15 statements pertaining to face validity (graphical appearance, endoscope and tissue behavior, overall realism), ≥50% of responses were "agree" or "strongly agree." In terms of content validity, 85.7% of participants agreed or strongly agreed that NOViSE is a useful training tool for NOTES and 71.4% that they would recommend it to others. Construct validity was established by comparing a number of performance metrics such as task completion times, path lengths, applied forces, and so on. NOViSE demonstrated early signs of construct validity. Experts were faster and used a shorter endoscopic path length than novices in all but one task. The results indicate that NOViSE authentically recreates a transgastric hybrid cholecystectomy and sets promising foundations for the further development of a VR training curriculum for NOTES without compromising patient safety or requiring expensive animal facilities.

Requirements analysis of a 5 degree of freedom haptic simulator for orthopedic trauma surgery.

There are currently few Virtual Reality simulators for orthopedic trauma surgery. The current simulators provide only a basic recreation of the manual skills involved, focusing instead on the procedural and anatomical knowledge required. One factor limiting simulation of the manual skills is the complexity of adding realistic haptic feedback, particularly torques. This paper investigates the requirements, in terms of forces and workspace (linear and rotational), of a haptic interface to simulate placement of a lag screw in the femoral head, such as for fixation of a fracture in the neck of the femur. To measure these requirements, a study has been conducted involving 5 subjects with experience performing this particular procedure. The results gathered are being used to inform the design of a new haptic simulator for orthopedic trauma surgery.

Development and Validation of a Virtual Reality Haptic Femoral Nailing Simulator.

OBJECTIVE: To create a virtual reality (VR) femoral nailing simulator combining haptics and image intensifier functionality and then carry out validation studies to assess its educational value. DESIGN: The simulator consisted of a 3D virtual environment, a haptic device and 3D printed drill handle and a VR headset. The environment was created using a video game development engine, interfaced with plugins to allow haptic feedback and image intensifier functionality. Two tasks were created within the simulator as part of an antegrade femoral intramedullary (IM) nail procedure: proximal guidewire entry and distal locking.For the validation study, participants performed the above tasks on the simulator. Metrics were collected including time taken, number of X-rays and tool distance travelled and used to assess construct validity. A questionnaire was then completed to assess authenticity and content validity. SETTING: Simulator development in centre for simulation and engagement science laboratory. Validation study in a teaching hospital environment. PARTICIPANTS: Orthopedic specialist trainees and consultants. RESULTS: Surgeon experience (number of IM nails performed/postgraduate year) correlated with significantly improved task performance. More experienced surgeons took less time, used fewer X-rays and had greater economy of movement than less experienced surgeons. Authenticity and content validity were well rated, with criticisms primarily due to hardware limitations. CONCLUSIONS: To our knowledge this is the first orthopedic simulator to combine immersive VR with haptics and full image intensifier functionality. By combining multiple aspects of surgical practice within a single device, we aimed to improve participant immersion and educational value. Our work so far has focused on technical skills, demonstrating good authenticity, content and construct validity, however our findings show promise in other applications such as nontechnical skill development and assessment.

NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator.

PURPOSE: Natural orifice transluminal endoscopic surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. METHODS: We developed NOViSE-the first force-feedback-enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom-built, and the behaviour of the virtual flexible endoscope is based on an established theoretical framework-the Cosserat theory of elastic rods. RESULTS: We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES. CONCLUSIONS: VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype, and the initial results indicate that it provides promising foundations for further development.