Pre-clinical Training for New Notes Procedures: From Ex-vivo Models to Virtual Reality Simulators

Natural orifice transluminal endoscopic surgery (NOTES) is a newer field of endoscopic surgery that allows for scarless treatment of pathologic entities, using novel transluminal approaches. There has been a shift of focus from a clinical and research standpoint from the development and dissemination of "first-generation" NOTES procedures to "new NOTES" procedures that traverse the mucosa of luminal structures, yet do not stray far into the peritoneal cavity. It has been a challenge to find appropriate and effective ways to train gastroenterologists and surgeons in these novel approaches. We review the importance of simulation in training and discuss available simulation options

Modelling and simulation of flexible instruments for minimally invasive surgical training in virtual reality

Improvements in quality and safety standards in surgical training, reduction in training hours and constant technological advances have challenged the traditional apprenticeship model to create a competent surgeon in a patient-safe way. As a result, pressure on training outside the operating room has increased. Interactive, computer based Virtual Reality (VR) simulators offer a safe, cost-effective, controllable and configurable training environment free from ethical and patient safety issues. Two prototype, yet fully-functional VR simulator systems for minimally invasive procedures relying on flexible instruments were developed and validated. NOViSE is the first force-feedback enabled VR simulator for Natural Orifice Transluminal Endoscopic Surgery (NOTES) training supporting a flexible endoscope. VCSim3 is a VR simulator for cardiovascular interventions using catheters and guidewires. The underlying mathematical model of flexible instruments in both simulator prototypes is based on an established theoretical framework – the Cosserat Theory of Elastic Rods. The efficient implementation of the Cosserat Rod model allows for an accurate, real-time simulation of instruments at haptic-interactive rates on an off-the-shelf computer. The behaviour of the virtual tools and its computational performance was evaluated using quantitative and qualitative measures. The instruments exhibited near sub-millimetre accuracy compared to their real counterparts. The proposed GPU implementation further accelerated their simulation performance by approximately an order of magnitude. The realism of the simulators was assessed by face, content and, in the case of NOViSE, construct validity studies. The results indicate good overall face and content validity of both simulators and of virtual instruments. NOViSE also demonstrated early signs of construct validity. VR simulation of flexible instruments in NOViSE and VCSim3 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. Moreover, in the context of an innovative and experimental technique such as NOTES, NOViSE could potentially facilitate its development and contribute to its popularization by keeping practitioners up to date with this new minimally invasive technique.Open Acces

Design, analysis and trajectory tracking control of underactuated mobile capsule robots.

The research on capsule robots (capsubots) has received attraction in recent years because of their compactness, simple structure and their potential use in medical diagnosis (e.g. capsule endoscopy), treatment and surgical assistance. The medical diagnostic capability of a capsule endoscope - which moves with the aid of visceral peristalsis - in the GI (gastro-intestinal) tract can be improved by adding propulsion to it e.g. legged, magnetic or capsubot-type propulsion. Driven by the above needs this thesis presents the design, analysis, trajectory tracking control and implementation of underactuated mobile capsule robots. These capsule robots can be modified and used in in-vivo medical applications. Researches on the capsubottype underactuated system focus on the stabilization of the robot and tracking the actuated configuration. However trajectory tracking control of an unactuated configuration (i.e. the robotmotion)was not considered in the literature though it is the primary requirement of any mobile robot and also crucial for many applications such as in-vivo inspection. Trajectory tracking control for this class of underactuated mechanical systems is still an open issue. This thesis presents a strategy to solve this issue. This thesis presents three robots namely a one-dimensional (1D) capsule robot, a 2D capsule robot and a 2D hybrid capsule robot with incremental capability. Two new acceleration profiles (utroque and contrarium) for the inner mass (IM) - internal moving part of the capsule robot - are proposed, analysed and implemented for the motion generation of the capsule robots. This thesis proposes a two-stage control strategy for the motion control of an underactuated capsule robot. A segment-wise trajectory tracking algorithm is developed for the 1D capsule robot. Theoretical analysis of the algorithm is presented and simulation is performed in the Matlab/Simulink environment based on the theoretical analysis. The algorithm is implemented in the developed capsule robot, the experimentation is performed and the results are critically analyzed. A trajectory tracking control algorithm combining segment-wise and behaviour-based control is proposed for the 2D capsule robot. Detailed theoretical analysis is presented and the simulation is performed to investigate the robustness of the trajectory tracking algorithm to friction uncertainties. A 2D capsule robot prototype is developed and the experimentation is performed. A novel 2D hybrid robot with four modes of operation - legless motion mode, legged motion mode, hybrid motion mode and anchoring mode - is also designed which uses one set of actuators in all operating modes. The theoretical analysis, modelling and simulation is performed. This thesis demonstrates effective ways of propulsion for in-vivo applications. The outer-shape of the 1D and 2D capsule robots can be customized according to the requirement of the applications, as the propulsion mechanisms are completely internal. These robots are also hermetically sealable (enclosed) which is a safety feature for the in-vivo robots. This thesis addresses the trajectory tracking control of the capsubot-type robot for the first time. During the experimentation the 1D robot prototype tracks the desired position trajectory with some error (relative mean absolute error: 16%). The trajectory tracking performance for the 2D capsubot improves as the segment time decreases whereas tracking performance declines as the friction uncertainty increases. The theoretical analysis, simulation and experimental results validate the proposed acceleration profiles and trajectory tracking control algorithms. The designed hybrid robot combines the best aspects of the legless and legged motions. The hybrid robot is capable of stopping in a suspected region and remain stationary for a prolonged observation for the in-vivo applications while withstanding the visceral peristalsis

Motor learning induced neuroplasticity in minimally invasive surgery

Technical skills in surgery have become more complex and challenging to acquire since the introduction of technological aids, particularly in the arena of Minimally Invasive Surgery. Additional challenges posed by reforms to surgical careers and increased public scrutiny, have propelled identification of methods to assess and acquire MIS technical skills. Although validated objective assessments have been developed to assess motor skills requisite for MIS, they poorly understand the development of expertise. Motor skills learning, is indirectly observable, an internal process leading to relative permanent changes in the central nervous system. Advances in functional neuroimaging permit direct interrogation of evolving patterns of brain function associated with motor learning due to the property of neuroplasticity and has been used on surgeons to identify the neural correlates for technical skills acquisition and the impact of new technology. However significant gaps exist in understanding neuroplasticity underlying learning complex bimanual MIS skills. In this thesis the available evidence on applying functional neuroimaging towards assessment and enhancing operative performance in the field of surgery has been synthesized. The purpose of this thesis was to evaluate frontal lobe neuroplasticity associated with learning a complex bimanual MIS skill using functional near-infrared spectroscopy an indirect neuroimaging technique. Laparoscopic suturing and knot-tying a technically challenging bimanual skill is selected to demonstrate learning related reorganisation of cortical behaviour within the frontal lobe by shifts in activation from the prefrontal cortex (PFC) subserving attention to primary and secondary motor centres (premotor cortex, supplementary motor area and primary motor cortex) in which motor sequences are encoded and executed. In the cross-sectional study, participants of varying expertise demonstrate frontal lobe neuroplasticity commensurate with motor learning. The longitudinal study involves tracking evolution in cortical behaviour of novices in response to receipt of eight hours distributed training over a fortnight. Despite novices achieving expert like performance and stabilisation on the technical task, this study demonstrates that novices displayed persistent PFC activity. This study establishes for complex bimanual tasks, that improvements in technical performance do not accompany a reduced reliance in attention to support performance. Finally, least-squares support vector machine is used to classify expertise based on frontal lobe functional connectivity. Findings of this thesis demonstrate the value of interrogating cortical behaviour towards assessing MIS skills development and credentialing.Open Acces

Investigation of a holistic human-computer interaction (HCI) framework to support the design of extended reality (XR) based training simulators

In recent years, the use of Extended Reality (XR) based simulators for training has increased rapidly. In this context, there is a need to explore novel HCI-based approaches to design more effective 3D training environments. A major impediment in this research area is the lack of an HCI-based framework that is holistic and serves as a foundation to integrate the design and assessment of HCI-based attributes such as affordance, cognitive load, and user-friendliness. This research addresses this need by investigating the creation of a holistic framework along with a process for designing, building, and assessing training simulators using such a framework as a foundation. The core elements of the proposed framework include the adoption of participatory design principles, the creation of information-intensive process models of target processes (relevant to the training activities), and design attributes related to affordance and cognitive load. A new attribute related to affordance of 3D scenes is proposed (termed dynamic affordance) and its role in impacting user comprehension in data-rich 3D training environments is studied. The framework is presented for the domain of orthopedic surgery. Rigorous user-involved assessment of the framework and simulation approach has highlighted the positive impact of the HCI-based framework and attributes on the acquisition of skills and knowledge by healthcare users