Melih Turkseven, PhD1, Mandeep S Sawhney, MD2, Suvranu De, ScD1, Daniel B Jones, MD2. 1Center for Modeling, Simulation and Imaging in Medicine (CeMSIM), Rensselaer Polytechnic Institute, 2Harvard Medical School
OBJECTIVE: Endoscopic Submucosal Dissection (ESD) is a technically challenging procedure for en bloc resection of large lesions (>20mm) . The procedure entails high risk due to complications such as perforations, aggressive bleeding. Despite its popularity in Asian countries, ESD is not common in the United States. Inadequate training platforms and lack of established training curriculums specific to the ESD procedure restrict is viewed as one of the causes. We are developing the first Virtual Endoscopic Submucosal Dissection Surgery Simulator (VESS) to provide a training platform for ESD. The ultimate goal of the VESS is to provide an effective training and assessment platform with highly realistic visualizations and a high fidelity haptic (touch) feedback.
Through a comprehensive task analysis, we have identified the major steps in ESD . In this work, we will present the details of the robotic platform designed to deliver haptic feedback involved.
DESCRIPTION OF TECHNOLOGY: VESS combines a high definition visual simulation with a haptic interface for a more immersive virtual experience in ESD simulation. The haptic interface, shown in Fig. 1, is a 2 degrees-of-freedom electromechanical device that is coupled to a dummy endoscope in order to provide the users with haptic feedback during the simulation.
Each degree-of-freedom is actuated by a Maxon electrical motor via capstan drives. The range in the push/pull direction is about 8 cm and in the rotary direction is 360 degrees, which was considered to be satisfactory for the ESD procedure. Each motor is equipped with rotary encoders to obtain the displacement of the endoscope. The knobs on the endoscope are also coupled to rotary encoders to monitor the deflection of its tip. The whole system is driven by a real-time target with FPGA interface (NI Myrio-1900).
The goal of the haptic interface is to replicate the resistance of the human colon to the motion of the endoscope and the deliver the interaction forces between the tooltip and the colon tissue during ESD.
PRELIMINARY RESULTS: We implemented force controllers on both actuators and checked the rate at which the controllers work. Our preliminary tests confirmed that the haptic interface can provide suitably large forces to the user with a loop rate up to 60 kHz, ensuring a high-resolution and chatter-free interaction experience.
CONCLUSIONS & FUTURE DIRECTIONS: The VESS simulator provides hands-on experience in ESD by the use of a virtual reality simulation coupled to a haptic interface. Our haptic interface matches the force and motion range typically involved in interventional endoscopic procedures. We plan to implement and test advanced control algorithms on the interface to satisfy the precision and stability of the haptic interactions that are essential to ESD.
 Y. Saito et al., “Indications for and technical aspects of colorectal endoscopic submucosal dissection,” Gut Liver, vol. 7, no. 3, pp. 263–269, 2013.
[2[ T. Halic et al., “Design of Virtual Endoluminal Submucosal Surgery Simulator (VESS)”, Digestive Disease Week, 2017.
Figure 1. The haptic Interface of Virtual Endoluminal Submucosal Surgery Simulator (VESS)
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 91173
Program Number: ETP878
Presentation Session: Emerging Technology iPoster Session (Non CME)
Presentation Type: Poster