Bipolar Cutting End Effector with Concentric Electrodes
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Solution Overview
Problem
Existing electrosurgical instruments face challenges in precise tissue cutting due to limitations in electrode placement and geometry, leading to issues with thermal spread, charring, and aberrant current densities, which affect the accuracy and efficiency of the cutting process.
Innovation Solution
The design of an electrosurgical instrument with a blade assembly featuring concentric electrodes of different lengths and polarities, supported by an insulator, which focuses electrosurgical energy to create a high power density cutting surface, minimizing energy effects on surrounding tissues and enhancing tissue division.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrosurgical instruments are used with standard electrode placement, then the cutting function is provided, but thermal spread and charring occur which reduce cutting precision
Solution Approach 1:
The patent applies local quality by creating a non-uniform electrode configuration where the active center electrode has a recessed tip and specific thickness, while the return electrodes are positioned at specific distances. This localized geometric variation concentrates the electrical field and current density precisely at the cutting edge, providing high cutting precision while limiting thermal spread to the immediate cutting zone only.
Solution Approach 2:
The patent employs asymmetry by using concentric electrodes of different lengths and configurations. The active center electrode has a recessed tip that extends beyond the return electrodes, creating an asymmetric electrical field distribution. This asymmetric geometry focuses the electrical field lines and current flow at the distal edge, enhancing cutting precision while controlling thermal effects.
2Measurement precision
If electrosurgical instruments with fixed electrode geometry are used, then the device structure is simple, but aberrant current densities and electrical fields reduce cutting accuracy
Solution Approach 1:
The patent applies parameter changes by varying the geometric parameters of the electrodes - specifically the thickness, length, and recessed tip configuration of the active center electrode, as well as the spacing and geometry of the return electrodes. These parameter variations are designed to optimize current density distribution and electrical field patterns, achieving superior cutting accuracy while maintaining a relatively simple overall device structure.
3Ease of operation
If manual contact method is used to apply electrosurgical instrument to tissue, then the device is easy to operate, but precise control of force and placement is difficult
Solution Approach 1:
The patent applies equipotentiality by designing the bipolar electrode configuration where both the active center electrode and the return electrodes are energized simultaneously. This creates a controlled electrical field between the electrodes that provides consistent and predictable tissue interaction, reducing variability in cutting performance and improving placement precision while maintaining ease of manual operation.
Data Source
AI summary
An electrosurgical instrument for cutting tissue includes a blade assembly. The blade assembly includes a first electrode having a first pre-selected shape and a first distal edge, and a second electrode disposed in spaced relation relative to the first electrode. The second electrode includes a second pre-selected shape and a second distal edge, where the first distal edge and the second distal edge form an electrically conductive tissue cutting surface extending along the distal end of the instrument. The tissue cutting surface is adapted to connect to a source of electrosurgical energy such that the tissue cutting surface is capable of conducting electrosurgical energy through tissue adjacent thereto to effectively cut tissue.