Electrosurgical Shears Knife Drive With Jaw-Closure Lockout
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Solution Overview
Problem
Existing electrosurgical instruments with scissor grip configurations face challenges in ensuring proper jaw closure for effective tissue sealing and efficient tissue cutting, particularly when flipped, and lack effective mechanisms to prevent accidental tissue damage during cutting.
Innovation Solution
A scissor-grip electrosurgical instrument with a resilient arm that flexes for enhanced jaw closure force and a compact firing assembly with a central trigger, combined with a lockout mechanism to ensure proper jaw closure before sealing or cutting, and an automatic knife return feature to prevent accidental tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a scissor grip configuration is used for electrosurgical instruments, then the instrument can be operated with a familiar grip pattern, but reliable jaw closure for effective tissue sealing and cutting becomes difficult to ensure, particularly when the instrument is flipped
Solution Approach 1:
The lockout mechanism prevents activation of the cutting element unless the jaws are properly closed, ensuring that tissue sealing and cutting only occur when the jaws are correctly positioned. This preliminary check of jaw closure status before allowing activation resolves the reliability issue while maintaining the familiar scissor grip operation
2Adaptability or versatility
If a translating tissue cutting element is added to electrosurgical instruments, then tissue cutting capability is improved, but accidental tissue damage during cutting increases due to lack of proper closure assurance
Solution Approach 1:
The lockout mechanism applies a counter-action by preventing activation of the cutting element unless proper jaw closure is achieved. This preliminary prevention stops potential accidental tissue damage before it can occur, while still allowing the translating cutting element to perform its intended tissue cutting function when conditions are proper
3Reliability
If a lockout mechanism is implemented to ensure proper jaw closure, then operational safety is improved, but device complexity increases
Solution Approach 1:
The lockout mechanism is integrated with the existing trigger assembly and jaw closure structure, combining multiple functions into a unified system. The lockout feature works together with the trigger mechanism and jaw closure elements that already exist in the instrument, reducing the need for separate independent components and minimizing overall complexity while maintaining operational safety
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
Ensures reliable tissue sealing and cutting with reduced risk of accidental damage by ensuring proper jaw closure and preventing unintended cutting, enhancing operational safety and efficiency.
Implementation Method 1
a resilient arm that flexes for enhanced jaw closure force
Implementation Method 2
one or more elements that transmit RF energy to tissue (e.g., to coagulate or seal the tissue)
Data Source
AI summary
A surgical instrument includes an end effector, a handle assembly, and a knife drive assembly. The end effector includes a pair of jaws, a knife, and an RF electrode assembly. The knife actuates between a pre-fired position and a fired position. An arm of the handle assembly is configured to pivot the second jaw between the open position and the closed position. The knife drive assembly includes an input assembly, a rotary assembly, and an output assembly. The input assembly travels a first proximal distance to rotate the rotary assembly. The rotary assembly rotates in response to travel of the input assembly along the first proximal distance to drive the output assembly a first distal distance to thereby actuate the knife from the pre-fired position toward the fired position. The first distal distance is greater than the first proximal distance.