Ultrasonic Surgical Instrument Force-Limiting Hinge
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Solution Overview
Problem
Ultrasonic surgical instruments face challenges in controlling the clamping force applied to tissue, which can lead to inconsistent tissue treatment and potential tissue damage due to excessive force.
Innovation Solution
The implementation of a force-limiting hinge assembly in an ultrasonic surgical instrument, which includes a hinge arm that flexes to regulate the clamping force between the jaw member and the ultrasonic blade, ensuring it does not exceed a maximum clamping force by coupling the shaft members with a pivotable and resiliently flexible hinge arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid coupling is used between shaft members to ensure stable clamping, then structural stability is improved, but the ability to regulate clamping force is lost leading to potential tissue damage
Solution Approach 1:
The hinge arm is designed as a resiliently flexible component that allows dynamic movement and flexing during clamping. This dynamic property enables the system to automatically regulate clamping force by flexing when maximum force is reached, preventing excessive force while maintaining structural stability during normal operation.
Solution Approach 2:
The hinge arm's resilient flexibility changes the mechanical parameters of the coupling between shaft members. By incorporating this flexible element, the system transitions from a rigid fixed-force coupling to a compliant coupling that can adaptively regulate force parameters, allowing the structure to flex and limit maximum clamping force.
2Ease of operation
If a flexible coupling is used to regulate clamping force, then control over clamping force is improved, but structural stability and precision are reduced
Solution Approach 1:
The hinge arm provides dynamic flexibility only when needed for force regulation. During normal clamping operation within the safe force range, the hinge arm remains substantially rigid, maintaining structural stability. The flexibility is activated dynamically only when the maximum clamping force is approached, allowing force control without compromising overall structural integrity.
Solution Approach 2:
The hinge arm's mechanical properties change based on the applied load. It maintains a rigid state for stable positioning and transitions to a flexible state only when the force threshold is reached. This parameter change allows the system to achieve both structural stability and clamping force control under different operational conditions.
3Device complexity
If no force-limiting mechanism is used, then device complexity is reduced, but tissue treatment reliability is compromised due to inconsistent clamping force
Solution Approach 1:
The hinge arm provides self-regulating force limitation without requiring external control systems, sensors, or complex feedback mechanisms. The resilient flexibility of the hinge arm itself serves as the force-limiting mechanism, automatically preventing excessive clamping force through its inherent mechanical properties, thus maintaining reliability while minimizing added complexity.
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 solution allows for consistent and controlled clamping force application, enhancing the reliability of tissue treatment by preventing excessive force and ensuring precise operation of the ultrasonic surgical instrument.
Implementation Method 1
The hinge arm is resiliently flexible and configured to flex to regulate a clamping force applied to tissue
Implementation Method 2
ultrasonic surgical instruments utilize mechanical vibration energy transmitted at ultrasonic frequencies to coagulate, cauterize, fuse, seal, cut, desiccate, and/or fulgurate tissue
Data Source
AI summary
An ultrasonic surgical instrument includes a first shaft member, a jaw member extending distally from the first shaft member, a second shaft member, an ultrasonic blade extending distally from the second shaft member and positioned to oppose the jaw member, and a force-limiting hinge assembly operably coupling the shaft members with one another such that movement of the shaft members between a spaced-apart position and an approximated position moves the jaw member and the ultrasonic blade between an open position and a clamping position for clamping tissue therebetween. The force-limiting hinge assembly includes a hinge arm fixedly engaged to one of the shaft members at a first end thereof and pivotably coupled to the other of the shaft members at a second end thereof. The hinge arm is configured to flex to regulate a clamping force applied to tissue clamped between the jaw member and the ultrasonic blade.