Robotic Control of a Traditional Flexible Endoscope

In flexible endoscopy the interior surfaces of the gastrointestinal, reproductive and respiratory tracts are assessed. The physician uses a flexible endoscope with a camera at the steerable distal tip that is introduced in the natural body openings. Instruments can be inserted in the endoscope. These protrude from the tip and enable performing interventions, like resection of small polyps. Current commercial available flexible endoscopes and its instruments have limited capacity to execute procedures that require advanced maneuverability. For that reason surgical procedures, like endoscopic submucosal dissection (ESD) of large lesions, are not generally adopted by gastroenterologists. The recent concept of natural orifice transluminal endoscopic surgery (NOTES) that asks even more dexterity is still in its infancy because of the lack of user-friendly sophisticated tools [1]. Main usability problems are related to the control section at the proximal end. Because of the configuration of control elements the physician often faces handling problems. For instance, approximately 20% of the physicians are using both hands for the control section, while an assistant manipulates shaft and instruments according to spoken instructions [2]. Drawback of this workflow is that the physician is missing valuable force feedback information on tissue interaction, and in addition communication errors easily occur. At present there are no flexible endoscopes available that can be controlled in an intuitive and user-friendly way by one person. Robotic technology has the potential to improve current practice and is likely to play a major role in performing advanced interventions easily and safely. Computer techniques, like motion scaling, can be implemented to support physicians. We propose a robotic system that interacts with a traditional flexible endoscope. In this way current endoscope qualities, like cleanability and good image quality, are maintained and costs related to replacement of endoscopic equipment is prevented. Previous work [3] concentrated on redesign of the control section to obtain single person endoscope steering for diagnosis. With the addition of instruments in therapeutics, single person control can only be obtained if the flexible endoscope can be operated with one hand and instruments with the other. We combined the robotic steering module that actuates the distal tip in [3] with a newly designed robotic module that actuates the shaft of the flexible endoscope. The physician uses one multi-degrees-of-freedom (multi-DOF) input controller to steer, advance, rotate, and maintain the position of the motorized flexible endoscope, while the other hand is able to manipulate instruments, as shown in Fig. 1. The control handle of the input controller resembles the endoscope tip. The operator experiences control like directly holding the camera at the distal tip and movements of the physician’s hand and the camera are matched to obtain intuitive manipulation. Robotic control is not intended for endoscope advancement in diagnosis that requires precise interpretation of interaction forces between endoscope and lumen, but it enables the physician to intuitively manipulate the tip of the endoscope in the operating area. It creates a stable endoscopic platform without the need of an assistant and allows for small robotic movements of the distal tip when the spatial range of the instruments is too small. We evaluated the usability of the robotic endoscope to perform these tasks compared to current flexible endoscopy.