In Vivo Layer-Specific Mechanical Characterization of Porcine Stomach Tissue Using a Customized Ultrasound Elastography System.

This paper presents in vivo mechanical characterization of the muscularis, submucosa, and mucosa of the porcine stomach wall under large deformation loading. This is particularly important for the development of gastrointestinal pathology-specific surgical intervention techniques. The study is based on testing the cardiac and fundic glandular stomach regions using a custom-developed compression ultrasound elastography system.

Ultrasound elastography reliably identifies altered mechanical properties of burned soft tissues.

Although burn injury to the skin and subcutaneous tissues is common in both civilian and military scenarios, a significant knowledge gap exists in quantifying changes in tissue properties as a result of burns. In this study, we present a noninvasive technique based on ultrasound elastography which can reliably assess altered nonlinear mechanical properties of a burned tissue. In particular, ex vivo porcine skin tissues have been exposed to four different burn conditions: (i) 200°F for 10s, (ii) 200°F for 30s, (iii) 450°F for 10s, and (iv) 450°F for 30s.

In Situ Mechanical Characterization of Multilayer Soft Tissue Using Ultrasound Imaging.

In this paper, we report the development of a technique to characterize layer-specific nonlinear material properties of soft tissue in situ with the potential for in vivo testing. A soft tissue elastography robotic arm system comprising of a robotically manipulated 30 MHz high-resolution ultrasound probe, a custom designed compression head, and load cells has been developed to perform compression ultrasound imaging on the target tissue and measure reaction forces. A multilayer finite element model is iteratively optimized to identify the material coefficients of each layer.

Face and content validation of a Virtual Translumenal Endoscopic Surgery Trainer (VTEST™).

Background: Natural orifice translumenal endoscopic surgery (NOTES) is an emerging surgical paradigm, where peritoneal access is achieved through one of the natural orifices of the body. It is being reported as a safe and feasible surgical technique with significantly reduced external scarring. Virtual Translumenal Endoscopic Surgical Trainer (VTEST™) is the first virtual reality simulator for the NOTES.

Development of a Soft Tissue Elastography Robotic Arm (STiERA).

High fidelity surgical simulations must rely upon accurate soft tissue models to ensure realism of the simulations. Simulating multi-layer tissue becomes increasingly complex due to the specific mechanical properties of each individual layer. We have developed a Soft Tissue Elastography Robotic Arm (STiERA) system capable of identifying layer specific properties of multi-layer constructs while maintaining the integrity of each layer.

Development of a Haptic Interface for Natural Orifice Translumenal Endoscopic Surgery Simulation.

Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive procedure, which utilizes the body's natural orifices to gain access to the peritoneal cavity. The NOTES procedure is designed to minimize external scarring and patient trauma, however flexible endoscopy based pure NOTES procedures require critical scope handling skills. The delicate nature of the NOTES procedure requires extensive training.

Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES.

Background: Natural Orifice Transluminal Endoscopic Surgery (NOTES) provides an emerging surgical technique which usually needs a long learning curve for surgeons. Virtual reality (VR) medical simulators with vision and haptic feedback can usually offer an efficient and cost-effective alternative without risk to the traditional training approaches. Under this motivation, we developed the first virtual reality simulator for transvaginal cholecystectomy in NOTES (VTEST™).

Towards immersive virtual reality (iVR): a route to surgical expertise.

Surgery is characterized by complex tasks performed in stressful environments. To enhance patient safety and reduce errors, surgeons must be trained in environments that mimic the actual clinical setting. Rasmussen's model of human behavior indicates that errors in surgical procedures may be skill-, rule-, or knowledge-based.

System characterization of a novel haptic interface for natural orifice translumenal endoscopic surgery simulation.

Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive procedure, which utilizes the body's natural orifices to gain access to the peritoneal cavity. The VTEST(©) is a virtual reality NOTES simulator developed at the CeMSIM at RPI to train surgeons in NOTES. A novel 2 DOF decoupled haptic device was designed and built for this simulator.

Characterization of force and torque interactions during a simulated transgastric appendectomy procedure.

We have developed an instrumented endoscope grip handle equipped with a six-axis load cell and measured forces and torques during a simulated transgastric natural orifice translumenal endoscopic surgery appendectomy procedure performed in an EASIE-R ex vivo simulator. The data were collected from ten participating surgeons of varying degrees of expertise which was analyzed to compute a set of six force and torque parameters for each coordinate axis for each of the nine tasks of the appendectomy procedure. The mean push/pull force was found to be 3.

Kinematic Measures for Evaluating Surgical Skills in Natural Orifice Translumenal Endoscopic Surgery (NOTES).

Natural Orifice Translumenal Endoscopic Surgery is an emerging procedure that requires training and adoption to be successful. Currently no objective performance metrics exist for evaluating skills for NOTES. In this work, we have improved upon our previous study on objective performance metrics using kinematic measures by introducing two new measures, the flex and the roll and recruiting more subjects to increase the statistical power.

A Decoupled 2 DOF Force Feedback Mechanism for the Virtual Translumenal Endoscopic Surgical Trainer (VTEST.

Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive procedure which utilizes the body's natural orifices to gain access to the peritoneal cavity. The VTEST is a virtual reality NOTES cholecystectomy simulator being built at the CeMSIM at RPI. We have developed a 2 DOF decoupled haptic device, which can provide translational and rotational haptic feedback to the user handling the flexible endoscope.

Development of a Virtual Reality Simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) Cholecystectomy Procedure.

The first virtual-reality-based simulator for Natural Orifice Translumenal Endoscopic Surgery (NOTES) is developed called the Virtual Translumenal Endoscopic Surgery Trainer (VTEST). VTEST aims to simulate hybrid NOTES cholecystectomy procedure using a rigid scope inserted through the vaginal port. The hardware interface is designed for accurate motion tracking of the scope and laparoscopic instruments to reproduce the unique hand-eye coordination.

Microsoft Kinect based head tracking for Life Size Collaborative Surgical Simulation Environments (LS-CollaSSLE).

Virtual surgical skills trainers are proving to be very useful for the medical training community. With efforts to increase patient safety and surgeon expertise, the need for surgical skills trainers that provide training in an operating room (OR) like condition is now more pressing. To allow for virtual surgery simulators to be instructed in an OR-like setting we have created a large display based immersive surgical simulation environment.

The development of a haptic interface for the Virtual Translumenal Endoscopic Surgical Trainer (VTEST.

Natural orifice translumenal endoscopic surgery (NOTES) is an experimental surgical technique with benefits including reduced pain, post operative recovery period and better cosmesis compared to traditional laparoscopic procedures. In a pure NOTES procedure, a flexible endoscope is used for performing the surgery and visualization. The Virtual Translumenal Endoscopic Surgical Trainer (VTEST(TM)) is being developed as a platform to train for NOTES procedures and innovate NOTES tools and techniques.

The use of rotational optical encoders for dial sensing in the Virtual translumenal Endoscopic Surgical Trainer (VTEST.

Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive procedure, known for its scar-less nature and short post operative recovery periods. A critical skill necessary for a NOTES procedure is the surgeon's ability to navigate and gain visualization of the target organ, which is done by moving the endoscope tip using the dials on the handle. We have developed an accurate and high resolution optical encoder based system to measure that dial manipulations, as part of a larger project to develop a VR-NOTES surgical simulator.

Objective performance measures using motion sensors on an endoscopic tool for evaluating skills in natural orifice translumenal endoscopic surgery (NOTES).

Natural orifice translumenal endoscopic surgery is an emerging procedure. High fidelity virtual reality-based simulators allow development of new surgical procedures and tools and train medical personnel without risk to human patients. As part of a project funded by the National Institutes of Health, we are developing a Virtual Transluminal Endoscopic Surgery Trainer (VTEST TM) for this purpose.

ToolTrack™: a compact, low-cost system for measuring surgical tool motion.

Accurate measurement of tool motion in minimally invasive procedures is an essential component of proficiency assessment. This is particularly important to automate the scoring procedures in, e.g.

Use of a linear motion stroke potentiometer as a high precision sensor for linear translation in a laparoscopic ligating loop simulation.

Virtual Basic Laparoscopic Skills Trainer (VBLaST) is a virtual reality trainer that replicates the Fundamentals of Laparoscopic Surgery (FLS) tasks for training in minimally invasive surgery. For the ligation loop task, we have developed a novel hardware interface using a linear motion stroke potentiometer to accurately sense the linear translation of the ligation loop and a mechanism to attach the tool interface to a PHANToM Omni for force feedback. Testing shows that the interface provided a realistic feel and control of the loop similar to the endoloop device used in FLS ligation loop task.