Agile Endoscopic Tools: Prototype concept of a deflectable ESD-Knife with single operator control

Aims Endoscopic Submucosal Dissection (ESD) is the mainstay of therapy for early gastrointestinal cancer. However, ESD is technically challenging and has a significant learning curve, that may result in prolonged procedure times and an increased risk of complications. Part of this problem are mechanical properties of the utilized endoscopes, which are mechanically optimized for supramillimeter movement precision. ESD however requires submillimeter movements. We hypothesize, that an independently movable ESD knife optimized for small-scale deflection might improve procedure precision and improve the learning curve. We also aimed for a single operator interface, that integrates the device interface with the established hand positions in conventional endoscope handling.

Methods We developed a prototype of an ESD knife featuring a novel bendable joint with an integrated electrode with a diameter of 2.6 mm. The prototype´s body consists of a 200 cm long, five-lumen extruded tube, enabling the integration of both the electrode and the actuation fibers for precise tip deflection. Four independently controlled micromotors, housed in a compact handle actuate this system. Dedicated software allows for control and customization of tip movement for accurate and responsive steering. A dedicated control unit with a joystick attached to the endoscope shaft allows for simultaneous control of both endoscope and knife movements by a single operator. The design allows for easy attachment and detachment of the control unit, ensuring compatibility with existing endoscopes and workflows.

Results The prototype of an ESD knife offers a full 360° range of motion with deflection of up to 30° controlled by a joystick integrated on a control unit at the endoscope shaft. This design may allow for intuitive single-operator operation and seamless integration into existing ESD workflows. In addition to controlling the ESD knife, the endoscope can be controlled as usual by the same surgeon. The control unit is designed to facilitate complex procedures while allowing maneuverability of the endoscope shaft for advancement, retraction, and rotation. Integrated digital assistance functions could further enhance control, including tip position lock and adjustable sensitivity settings for fine movements.

Conclusions This study demonstrates the feasibility of independent actuation in an instrument fitting into the challenging design space constraints of a typical 2.8 mm endoscope working channel and its successful ex-vivo evaluation. Future studies will focus on evaluating the device's performance and usability in preclinical and clinical settings and investigate if independent movement of the ESD knife might increase precision, shorten the learning curve, and improve outcomes for patients undergoing ESD.

Publication History

Article published online:
27 March 2025