An active endoscope with small sweep volume that preserves image orientation for arthroscopic surgery.

BACKGROUND: Microsurgery is generally performed in narrow spaces with limited movement. Endoscopes that allow for angle changes have been developed using elastic materials, but they require a large bending space. We propose a new endoscope with a small sweep volume for angle changes. METHODS: We fabricated a prototype with a thumb-operated joystick. The image sensor is attached to the tooltip. The image signal is input to a motor control board which computes inverse kinematics and transforms it into joint angle values. Each axis is positioned according to these values. RESULTS: The tooltip sweeping volume was 104 mm3 . Surgeons at the Asan Medical Center used our endoscope to obtain images of the biceps tendon and subscapularis joints of a cadaver. CONCLUSION: Currently, a low-resolution image sensor is attached to endoscope tooltips. In the future, we will develop a high-resolution image module equipped with an ultra-small complementary metal oxide semiconductor sensor.

Active Endoscope Preserving Image Orientation for Endonasal Skull Base Surgery.

Endonasal Skull Base Surgery has some advantages over conventional methods; however, some issues such as the need to replace the endoscope due to the fixed view, and possible invasiveness during insertion make the procedure difficult. To solve these problems, this paper proposes an active endoscope mechanism with several benefits. First, its variable direction of view can cover the wide ranges. Second, it provides a forward view, lessening the danger of damaging critical tissues while the endoscope is being inserted. Third, it can change the direction of view within a very small radius of 6.5 mm, so it can be used in a small cavity and work together with other surgical tools. We have designed the endoscope, which has 4 mm diameter. It is a simple tilting and rotation mechanism of 2-degree of freedom (DOF). It implements kinematics control to make it intuitive to operate. The image sensor attached to the distal end is fixed mechanically so that the image orientation is preserved in the direction of gravity. The experiments showed the user could intuitively control the endoscope with the master device and observe the target without swapping the endoscope. Future tests will examine clinical aspects and combination work with surgical instruments.

Intuitive Hand-held Instrument for Loose Body Removal in Arthroscopic Synovial Chondromatosis Surgery.

In order to treat synovial chondromatosis in minimally invasive way, the loose bodies in the joint cavity should be removed with arthroscopic surgery. However, since the joint cavity is narrow and round, it is difficult to approach with conventional straight surgical tools. To overcome this, existing studies have proposed motorized steerable surgical instruments, but they do not provide haptic feedback and intuitive understanding of the position of the end-effector. In this paper, we developed a motorless steerable arthroscopic surgery instrument. It was designed with the ergonomic aspects for intuitive manipulation. It is geometrically modeled to define the mechanical parameters; diameter 5 mm, bending angle 90°. Design values and clinical significance were verified by an experiment and a phantom test.

A Steerable Endoscope for Transnasal Skull Base Surgery.

In this paper, we described the development of an endoscopic system with the application of minimally invasive observation for a pituitary tumor or a craniopharyngioma. The end-effector was manufactured by attaching an image sensor to the end of a manipulator with a diameter of 3 mm (smaller than a commercial endoscope) by making slits on a biocompatible PAI (Polyamide-imide) tube. The end-effector having 2 degrees of freedom for bending is designed not only to cover most of the FOVs (92.8% of the goal) with commercially available fixed-angle endoscopes at 0, 30, and 70 degrees, but also to be able to maneuver the endoscope intuitively. The system consists of a controller, a foot switch, and the end-effector. Through qualitative experiments, basic verification of the proposed system was tested and the potential of this study was recognized through user evaluations from 3 specialists, which generated positive feedback upon the operational procedures.