Robotic steering of flexible endoscopes

Abstract

SummaryFlexible endoscopes were originally designed for non-invasive inspection of body cavities and hollow organs. Today, they are also used for complex minimal invasive interventions. Control of the endoscope is difficult and complexity rises with interventional procedures. Endoscopists suffer from long learning curves, ergonomic complaints and multi-person control is needed to steer endoscope and instrument(s).Robotics have the potential to overcome these problems. The combined forces of a technical university, mechatronic company and physicians from multiple hospitals led to the design of an add-on robotic platform. The platform aims to improve usability of conventional flexible endoscopes for complex interventions. These interventions require accurate and precise tip steering.This thesis describes the design and clinical evaluation of the platform's tip steering module. An optimal user interface and control algorithm was sought to improve usability of the endoscope in clinical practise.First, critical user aspects of conventional gastro-and colonoscopes were identified and copied to the robotic platform. The control module includes a remote interface that was evaluated by novices in a simulated colonoscopy environment. This study indicated that robotic steering, using a position-controlled touchpad or a ratecontrolled joystick increases efficiency and satisfaction. However, breaking the mechanical linkage between operator and endoscope tip led to a lack of force feedback on tip bending.The first results did not show a clear preference between two regular user interfaces and their control algorithms. A position-controlled touchpad has benefits for precise targeting (instrument placement), whereas a rate-controlled joystick is better suited for quick tip steering (lumen navigation). Endoscopy requires both quick and precise tip motions. The second study describes the design of a non-linear rate iii control algorithm. This study showed that between regular intuitive interfaces, the joystick with non-linear rate control showed highest efficiency and users' preference.A single-handed controller was introduced to further reduce the experienced workload of flexible endoscopy. The controller was compared to a bimanual interface and conventional control in a simulated colonoscopy procedure. Both the single-handed and a bimanual controller reduced the workload of colonoscopy without reducing efficiency or effectiveness. Despite the single-handed approach, novices appeared to steer the endoscope tip and shaft consecutively, not simultaneously. Making bimanual control the logical route to pursue.The first three studies indicated that the platform changed the current routine of handling an endoscope. A fourth study was designed to determine if expert endoscopists and endoscopists in training were able to perform the complex manoeuvres required in colonoscopy. Experts and PhD students without previous hands-on experience trained on a computer simulator to perform colonoscope intubation. Experts needed a relatively short ...