Ultrasonic Tissue Pad with Force-Limiting Mechanism
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Solution Overview
Problem
Current ultrasonic surgical instruments face issues such as tissue tags, inadequate tissue pad longevity, excessive force leading to component failure, and cumbersome activation mechanisms, which affect the efficiency and reliability of tissue cutting and coagulation during surgical procedures.
Innovation Solution
The ultrasonic surgical clamp coagulator apparatus features a clamping mechanism with a pivotally mounted clamp arm and advanced tissue pad design, a force-limiting mechanism to smooth out abusive tissue forces, and hand activation with ergonomically designed switches to improve grip and operation, allowing for selective cutting, coagulation, and clamping with enhanced control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tissue pads are designed to provide sufficient clamping force for effective tissue cutting, then cutting efficiency is improved, but tissue pad longevity deteriorates due to excessive wear and material failure
Solution Approach 1:
The patent applies parameter changes by modifying the tissue pad material composition and mechanical properties. The tissue pad is designed with specific durometer ranges (40-70 Shore A) and material formulations that balance softness for tissue compliance with durability for extended use. This allows the pad to provide sufficient clamping force for effective cutting while resisting wear and degradation over time, directly resolving the contradiction between cutting efficiency and pad longevity.
Solution Approach 2:
The patent employs composite materials by combining multiple material properties within the tissue pad structure. The pad integrates viscoelastic materials with specific tensile strength, elongation at break, and tear resistance characteristics. This composite approach enables the pad to simultaneously achieve the softness needed for tissue conformity and the strength required for durability, resolving the conflict between effective clamping force application and extended service life.
2Productivity
If higher clamping forces are applied to improve tissue transaction, then cutting performance is improved, but component failure increases due to excessive forces on the blade and mechanism
Solution Approach 1:
The patent applies parameter changes by precisely controlling the clamping force within optimal ranges through spring mechanism design. The spring constant and preload are calibrated to generate sufficient clamping force for effective tissue cutting (improving productivity) while staying below thresholds that would cause blade damage or mechanism failure (maintaining reliability). This parameter optimization directly resolves the contradiction between cutting effectiveness and component durability.
3Reliability
If the clamp arm is designed to apply sufficient loading force against the tissue, then tissue coagulation effectiveness is improved, but the activation mechanism becomes more complex and harder to operate
Solution Approach 1:
The patent applies self-service through the spring-loaded clamp arm mechanism that automatically generates and maintains the required clamping force without continuous surgeon input. Once activated, the spring mechanism self-regulates the force application, ensuring consistent tissue coagulation effectiveness. This automation reduces operational complexity while maintaining reliable coagulation performance, resolving the contradiction between effectiveness and ease of operation.
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 solution enables increased tissue clamping forces, improved pad durability, and ergonomic operation, reducing tissue tags and component failure risks, while enhancing the surgeon's ability to control tissue cutting and coagulation, thus improving surgical precision and efficiency.
Implementation Method 1
The cutting action is typically effected by an end-effector at the distal end of the instrument, which transmits ultrasonic energy to tissue brought into contact with the end-effector
Implementation Method 2
Ultrasonic surgical instruments have been developed that include a clamp mechanism to press tissue against the blade of the end-effector in order to couple ultrasonic energy to the tissue of a patient
Data Source
AI summary
An ultrasonic clamp coagulator assembly that is configured to permit selective cutting, coagulation and clamping of tissue during surgical procedures. An elongated portion of the instrument can be configured for endoscopic applications and has an outside diameter of less than 6 mm. The construction includes a clamping mechanism, including a clamp arm pivotally mounted at the distal portion of the instrument, which is specifically configured to create a desired level of tissue clamping forces, exceeding 4 pounds when the trigger is fully closed. The clamping mechanism includes a two-piece pad design and pad material that enables the higher tissue clamping forces and a force-limiting mechanism that effectively smooths out abusive tissue forces. The assembly also features hand activation configured to provide an ergonomical grip and operation for the surgeon. Hand switches are placed in the range of the natural swing of the surgeon's thumb, whether gripping the surgical instrument right-handed or left handed.