Electrosurgical Forceps with Lossy Transmission Lines
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Solution Overview
Problem
Existing electrosurgical forceps face limitations in delivering controlled microwave and RF energy to biological tissue, particularly in ensuring efficient energy delivery and minimizing power loss, especially when tissue is not present, which affects the effectiveness of procedures like vessel sealing and coagulation.
Innovation Solution
The design incorporates non-resonant unbalanced lossy transmission line structures on the jaws of the forceps, acting as both active and return electrodes for RF energy and lossy structures for microwave energy, with the geometry optimized to ensure high power delivery into tissue while minimizing power loss in air, using a coaxial cable and elongate conductive elements to facilitate efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bipolar electrodes are used for RF energy delivery, then vessel sealing can be achieved through thermal denaturation, but the ability to deliver microwave energy is limited and power loss cannot be controlled
Solution Approach 1:
The elongate conductive elements are designed to perform multiple functions: they serve as active and return electrodes for RF energy delivery, and simultaneously function as lossy transmission line structures for microwave energy delivery. This multi-functionality allows a single structure to handle both RF and microwave energies, achieving versatility without requiring separate electrode systems.
Solution Approach 2:
The conductive elements are designed with specific geometric parameters (dimensions, spacing, configuration) that can be optimized to control power loss characteristics. By adjusting these parameters, the transmission line structures can be tuned to minimize power loss for microwave energy while maintaining effective RF energy delivery, thus controlling energy loss through parameter optimization.
2Power
If microwave antennas are used for microwave energy delivery, then tissue sealing can be achieved, but the electrode configuration is restricted and device flexibility is reduced
Solution Approach 1:
The patent replaces traditional microwave antenna structures with lossy transmission line structures formed by elongate conductive elements. This substitution allows microwave energy to be delivered through a simpler, more flexible transmission line configuration rather than requiring complex antenna designs, thereby reducing device complexity while maintaining microwave delivery capability.
Solution Approach 2:
The transmission line structures are designed to be adaptable to different jaw configurations and tissue types. The elongate conductive elements can be positioned and configured flexibly within the jaw structure, allowing the device to adapt to various surgical scenarios without requiring fixed, complex antenna arrangements, thus improving device flexibility.
3Power
If resonant transmission line structures are used, then microwave energy can be delivered, but power loss increases and control over energy delivery is reduced
Solution Approach 1:
The transmission line structures are designed in advance with specific non-resonant characteristics and lossy properties. By pre-configuring the conductive elements with appropriate dimensions, spacing, and materials before use, the system is prepared to deliver microwave energy with controlled power loss, eliminating the need for complex real-time adjustments during surgical procedures.
Solution Approach 2:
The patent intentionally introduces lossy characteristics into the transmission line structures, converting what would normally be considered a disadvantage (power loss) into a beneficial feature. The controlled power loss in the transmission lines ensures that microwave energy is delivered efficiently to the tissue while preventing excessive power reflection and improving overall energy transfer control, thus turning potential harm into benefit.
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 configuration allows for controlled and efficient delivery of energy to tissue, enhancing procedures like vessel sealing and coagulation by maximizing power transfer when tissue is present and minimizing power loss when tissue is absent, thus improving the effectiveness and flexibility of electrosurgical procedures.
Implementation Method 1
lossy structures for delivering a microwave signal into biological tissue
Implementation Method 2
lossy transmission line structure for microwave energy conveyed by the coaxial cable
Implementation Method 3
delivering controlled microwave and RF energy to biological tissue
Implementation Method 4
bipolar electrode arrangement in the jaws of the forceps. The RF energy may be used to seal vessel by thermal denaturation
Implementation Method 5
RF energy for cutting the tissue... thermal denaturation of extracellular matrix proteins
Data Source
AI summary
Electrosurgical forceps in which one or more pairs of non-resonant unbalanced lossy transmission line structures are arranged on the inner surfaces of the jaws of the forceps provide both (i) active and return electrodes for a radiofrequency (RF) signal, and (ii) lossy structures for delivering a microwave signal into biological tissue in conjunction with a mechanical gripping arrangement for applying pressure to material held within the jaws. The location of the pairs of transmission lines on the jaws of the forceps and the selection of the material of the jaws is arranged to ensure that any biological tissue gripped by the jaws become the propagation medium for the RF signal and the medium into which the microwave signal is lost.