Electrosurgical Shears Dual-Stage Activation Mechanism
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Solution Overview
Problem
Existing electrosurgical instruments with elongate shafts and handle assemblies can be cumbersome and difficult to use, especially when trying to actuate cutting features or apply RF energy, as the lever arms can become awkward to manipulate, particularly when the instrument is flipped.
Innovation Solution
The design of an electrosurgical forceps instrument with a scissor grip configuration, featuring a resilient arm that flexes to provide greater closure forces for sealing tissue and a compact firing assembly with a trigger close to the center of the housing, allowing easy actuation of the knife and RF energy activation, even when the instrument is flipped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If an electrosurgical instrument uses an elongate shaft with handle assembly, then it can reach deep surgical sites, but it becomes cumbersome and difficult to manipulate, especially when flipped
Solution Approach 1:
The instrument is divided into distinct functional segments: a long elongate shaft for reach, a handle assembly for control, and a separate end effector with jaws and cutting element. This segmentation allows each component to be optimized independently - the shaft provides reach while the handle assembly with its centered trigger maintains ease of manipulation regardless of instrument orientation
2Force
If the trigger is positioned far from the center of the housing, then it can provide better leverage, but it becomes awkward to actuate when the instrument is flipped
Solution Approach 1:
The trigger mechanism is merged with the central housing structure rather than being positioned at the end of a lever arm. The trigger is receptively engaged within the handle assembly housing, combining the activation function with the central structural element. This eliminates the leverage-ease of operation tradeoff by removing the need for a distant trigger position while maintaining effective actuation force through the centralized design
3Force
If the resilient arm is made more flexible to provide greater closure forces, then tissue sealing effectiveness improves, but the structure becomes less stable
Solution Approach 1:
The resilient arm transitions from a static rigid structure to a dynamic flexible component that adapts its properties during operation. The arm is designed with controlled flexibility to provide enhanced closure forces when needed during tissue grasping and sealing, while maintaining sufficient structural stability in its resting and operational positions. This dynamic characteristic allows the arm to be compliant during tissue manipulation yet stable during energy delivery
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
This design enhances the ease of use by providing sufficient closure forces for effective tissue sealing and cutting, while preventing accidental activation and reducing the risk of tissue damage, with a user-friendly interface that maintains functionality regardless of the instrument's orientation.
Implementation Method 1
a resilient arm that flexes to provide greater closure forces for sealing tissue
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 an electrode activation assembly. The end effector includes a first jaw, a second jaw, a knife, and an electrode assembly. The handle assembly includes a housing, and an arm. The arm can pivot the second jaw between the open position and the closed position. The arm can pivot relative to the housing between a first position, a second position, and a third position. The electrode activation assembly includes an activation button associated with the handle assembly, a resilient body, and a detent associated with either the housing or the arm. The activation button can activate the electrode assembly in response to the arm pivoting to the third position. The resilient body includes a first cam feature. The detent can engage the first cam feature as the arm pivots between the first position and the second position.