Thermal Cutting Wire with Ferromagnetic Coating
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Solution Overview
Problem
Existing electrosurgical instruments face challenges in accurately and efficiently cutting treated tissue, as mechanical knives can be cumbersome and energy-based cutting methods may not provide precise control over temperature and tissue severing.
Innovation Solution
The development of electrosurgical instruments featuring a thermal cutting wire with a ferromagnetic coating that undergoes automatic Curie temperature control when supplied with an AC signal, allowing for precise and self-regulating heat application for cutting tissue, with customizable Curie temperatures and coatings for independent activation of different wire portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical knife is used to cut tissue, then cutting function is provided, but the instrument becomes cumbersome and complex
Solution Approach 1:
The patent replaces the mechanical knife system with a thermal cutting element that uses ferromagnetic heating. Instead of mechanically advancing a blade through tissue, the invention uses a wire with ferromagnetic coating that generates heat when exposed to an alternating magnetic field, thereby cutting tissue through thermal action rather than mechanical force.
Solution Approach 2:
The invention extracts the cutting function from the mechanical jaw closure mechanism and separates it into an independent thermal cutting element. The wire is positioned within the jaw members but operates independently from the clamping action, allowing cutting to occur without requiring complex mechanical knife advancement mechanisms.
2Manufacturing precision
If energy-based cutting is used, then cutting function is provided, but temperature control precision is insufficient
Solution Approach 1:
The ferromagnetic coating on the wire provides self-regulating temperature control through its inherent Curie temperature. When the wire reaches the Curie temperature, the ferromagnetic properties change, automatically limiting further temperature increase without requiring external sensors or feedback mechanisms. This self-service temperature regulation simplifies the device while improving precision.
Solution Approach 2:
The invention utilizes the Curie temperature parameter of ferromagnetic materials to establish a predetermined maximum operating temperature. By selecting materials with specific Curie temperatures, the system achieves precise temperature control tailored to different surgical applications, cutting off heat generation automatically when the threshold is reached.
3Reliability
If ferromagnetic coating is applied to thermal cutting wire, then automatic temperature control is achieved, but manufacturing complexity increases
Solution Approach 1:
The invention uses composite construction with a core wire and an outer ferromagnetic coating layer. This composite structure combines the electrical conductivity and mechanical strength of the core material with the temperature-regulating properties of the ferromagnetic coating, achieving reliable automatic temperature control while maintaining manufacturability through established coating techniques.
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
Enables precise and efficient cutting of treated tissue with automatic temperature regulation, reducing the need for sensors and feedback mechanisms, and providing consistent heating to prevent overheating, while allowing for customizable cutting wire configurations for various surgical applications.
Implementation Method 1
The first and second portions of the thermal cutting wire each include a ferromagnetic coating such that the first and second portions are ferromagnetically heated and provide automatic Curie temperature control upon supply of an AC signal thereto
Data Source
AI summary
An electrosurgical instrument includes an end effector assembly including first and second jaw members. At least one of the first or second jaw members is movable relative to the other from a spaced-apart position to an approximated position to grasp tissue therebetween. A thermal cutting wire is disposed on at least a portion of at least one of the first or second jaw members. The thermal cutting wire is configured for ferromagnetic heating to provide automatic Curie temperature control upon supply of an AC signal thereto. The thermal cutting wire may include a conductive core, an inner ferromagnetic coating disposed about the conductive core, and an outer ferromagnetic coating disposed about the inner ferromagnetic coating. The thermal cutting wire may alternatively or additionally include an exposed outer surface defining a roughness configured to facilitate attenuation during ferromagnetic heating.