Electrosurgical Instrument with Spring-Actuated Cutting Element
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Solution Overview
Problem
Existing electrosurgical instruments face challenges in creating strong, immediate tissue welds, particularly for large diameter blood vessels, as they often require high strength immediately post-treatment and struggle with irregular or thick tissue structures.
Innovation Solution
The development of an electrosurgical instrument with a handle, elongate shaft, and end effector featuring movable jaw members and a tissue-cutting element, where a spring and trigger mechanism regulate energy release and cutting, and an axially movable member with a tissue-cutting element translates to close and open jaws, ensuring controlled energy application and cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high energy is applied to create strong tissue welds, then weld strength is improved, but tissue damage and loss of control increase
Solution Approach 1:
The instrument applies RF energy to the tissue before cutting to pre-weld or seal the tissue, creating strong welds in advance. This preliminary action ensures that when the cutting element transects the tissue, the weld strength is already established, preventing tissue damage during the cutting process.
Solution Approach 2:
The instrument uses periodic or pulsed RF energy delivery rather than continuous energy application. This allows the tissue to heat and weld in controlled intervals, building weld strength progressively while preventing excessive temperature rise and tissue damage. The periodic action enables precise control over the welding process.
2Reliability
If continuous RF energy is applied to seal tissue, then sealing is improved, but heat accumulation and tissue damage increase
Solution Approach 1:
The instrument employs periodic RF energy delivery in controlled pulses rather than continuous application. This allows the tissue to seal effectively during each pulse while providing brief intervals for heat dissipation, preventing dangerous heat accumulation. The periodic action maintains reliable sealing while controlling temperature rise.
Solution Approach 2:
The instrument incorporates feedback mechanisms to monitor tissue response and adjust RF energy delivery in real-time. When the tissue reaches the optimal temperature for sealing, the feedback system reduces or pauses energy delivery, preventing excessive heat accumulation. This feedback control ensures reliable sealing while maintaining safe temperature levels.
3Productivity
If the cutting element moves rapidly through tissue, then cutting speed is improved, but precision and control decrease
Solution Approach 1:
The instrument first applies RF energy to the tissue to pre-weld or seal it, then the cutting element transects the pre-treated tissue. This preliminary action softens and secures the tissue, allowing the cutting element to move through with controlled precision rather than raw speed, improving both cutting precision and productivity.
Solution Approach 2:
The instrument dynamically adjusts the movement of the cutting element based on tissue response and energy delivery. The cutting element can be advanced at variable speeds, allowing rapid cutting when tissue is pre-treated and slower, more precise movement when encountering resistance or requiring additional sealing. This dynamic control optimizes both speed and precision.
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 instrument achieves strong, immediate tissue welds by controlled energy delivery and precise cutting, effectively sealing and transecting tissues, including large diameter blood vessels, with enhanced precision and control.
Implementation Method 1
a spring operably coupled to the trigger, the spring to release energy and distally translate the axially movable member
Implementation Method 2
electrical current can flow from one electrode, through the tissue, and to the other electrode. The surgical instrument can comprise an electrical input, a supply conductor electrically coupled with the electrodes
Implementation Method 3
RF energy is a form of electrical energy that may be in the frequency range of 300 kilohertz (kHz) to 1 megahertz (MHz). In application, RF surgical instruments transmit low frequency radio waves through electrodes, which cause ionic agitation, or friction, increasing the temperature of the tissue
Implementation Method 4
the energy can at least partially denature proteins within the tissue. Such proteins, such as collagen, for example, may be denatured into a proteinaceous amalgam that intermixes and fuses, or 'welds', together as the proteins renature
Data Source
AI summary
A surgical instrument for supplying energy to tissue can comprise a jaw member comprising an electrode, wherein the electrode is configured to supply energy from a power source to captured tissue. The surgical instrument comprises a tissue-cutting element to transect the captured tissue. The rate of distal translation of the tissue-cutting element during the operational stroke may be regulated by a linear actuator, for example.