High-frequency Knife Axial Projection for Mucosal Resection
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Solution Overview
Problem
Conventional high-frequency surgical instruments for endoscopic tissue resection lack the necessary degree of freedom and precision in incising organic tissues, particularly mucous membranes, due to limited directional movement and risk of unintended tissue engagement during the procedure.
Innovation Solution
A high-frequency knife design featuring a cylindrical body with a conductive axial member and insulating components, allowing for axial projection and retraction, and featuring second electrode portions that extend radially from the first electrode portion, enabling lateral and longitudinal movement for enhanced incision control and preventing current flow into unresectable tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a needle-shaped knife section is used for endoscopic tissue resection, then the instrument can cauterize and incise organic tissue, but the degree of freedom and precision in incising is limited
Solution Approach 1:
The knife section is designed to be movable relative to the sheath, allowing it to project forward and retract. This dynamic configuration enables the knife to move not only in the axial direction but also laterally, providing enhanced degree of freedom and precision in incising organic tissues while maintaining safe retraction when not in use
Solution Approach 2:
The instrument is divided into distinct functional segments: the sheath providing insulation and protection, the movable knife section for cutting, and the insulating member for electrical isolation. This segmentation allows each component to perform its specific function optimally, with the knife section able to move independently for precise incisions
2Device complexity
If the knife section extends axially without additional insulating members, then the structure is simpler, but unintended tissue engagement may occur during manipulation
Solution Approach 1:
An insulating member is introduced as an intermediary element between the conductive knife section and the surrounding environment. This insulating member prevents unintended electrical engagement with tissues during knife manipulation, allowing the surgeon to move the knife freely without risk of accidental cauterization
Solution Approach 2:
The insulating function is extracted from the sheath and implemented as a separate insulating member that can be positioned independently. This allows the sheath to focus on mechanical protection while the insulating member specifically addresses electrical isolation, improving overall reliability
3Power
If high-frequency current is supplied to the needle-shaped knife section, then tissue cauterization and incision is achieved, but control over current flow direction is limited
Solution Approach 1:
The movable knife section allows dynamic positioning and directional control during tissue resection. By projecting the knife forward and positioning it at specific angles, the surgeon can control the direction of current flow and incision path, enabling precise removal of lesioned mucosal parts with better power control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design allows for more versatile and precise resection of mucous membranes with improved cutting quality by enabling multiple directional movements and minimizing engagement with unintended tissues, thus facilitating easier and more effective lesion removal.
Implementation Method 1
If high-frequency current is supplied to the needle-shaped knife section, an organic tissue that is touched by the knife section can be cauterized and incised
Implementation Method 2
The insulating member is provided on the distal end of the axial member in a position at a distance from the distal end of the body member
Data Source
AI summary
A high-frequency knife includes a cylindrical body member, electrically conductive axial member, operating section, and electrical insulating member. At least an outer peripheral surface of the body member has insulating properties. The axial member is inserted in the body member. A distal end portion of the axial member has a knife section. The operating section is provided on a proximal end portion of the axial member, can be actuated by a surgeon to project and retract the axial member with respect to the body member, and can supply electric power to the axial member. The insulating member is provided on the distal end of the axial member in a position at a distance from the distal end of the body member and has at least the longest axis of a cross section of the knife section.