Setup and initial testing of an endoscope manipulator system for assistance in transoral endoscopic surgery

Purpose For the treatment of malignant diseases of the oral cavity and the larynx, a total or partial resection is the standard therapy, while in special cases chemo- and/or external radiation therapy is considered. Transoral access reduces trauma and hospitalization time. Transoral surgery is usually executed using external microscopic imaging. Therefore, the microscope is placed in the visual line of the opening of the mouth and throat. However, specific anatomical structures like the posterior commissure (dorsal end of the vocal cords) are not visible in these procedures. An endoscopic approach can improve this problem. We introduce a new prototype system for endoscopic assisted transoral surgery. Methods Based on clinical observation and discussions with professional users and surgeons, the clinical need was identified and specified. A general concept or an endoscopic manipulator to assist microlaryngeal surgery was designed. For that a steerable rigid endoscope was combined with an actuator that allows translational and rotational movement. A quick release fastener was designed allowing for fast change of the endoscope and independence from its shape and type. The actuator was fixed on a commercially available, semi-active medical holding arm for easy positioning. The holder can be fixed to the standard rails of the surgical table. The piezoelectric drives integrated in the actuator are activated with a foot pedal. This allows easy and fast fine positioning, while the hands are free to perform the surgery with standard instruments for microlaryngeal surgery. Results A prototype of the system for endoscopic assisted transoral surgery was developed. The entire technical setup was tested in terms of usability and performance in a simulated surgical scenario. A basic phantom, representing the throat and vocal cords was created and placed on a surgical table. The system was installed on the table and the clinical workflow of a simulated endoscopic assisted surgery on the vocal cords was performed. The performance of the setup and the procedure success was evaluated by clinical users. Conclusion Fixture of the system on the surgical table is fast and easy due to its low weight and compact design. The medical holder allows a fast initial positioning of the system in front of the phantom patient. An easy insertion and removal of the endoscope was realized using the quick release fastener. The developed endoscope fixation is universally adaptable and not limited to a single type of endoscope. The piezoelectric drives, combined with the foot pedal, allow a precise placement and readjustment of the endoscope during surgery. The use of a multi view endoscope enables a variable view on the surgical situs. The size and shape of the whole setup offer excellent access to the targeted structures. The development was classified beneficial by the clinical users.