Hollow RF Cable Structure for Low-Loss Electrosurgical Power Delivery
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Solution Overview
Problem
Conventional cables for conveying radiofrequency and/or microwave energy to electrosurgical instruments are inefficient due to wasted space, leading to power losses and off-centre positioning of additional components, which can hinder instrument operation.
Innovation Solution
A hollow cable design with inner and outer electrically conductive layers separated by dielectric material, allowing additional components to be passed through, maximizing cable diameter and reducing power losses, and positioning actuation components closer to the center for improved instrument actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional cables with additional tubes are used to provide supplies or components to electrosurgical instruments, then additional functions can be provided, but significant space is wasted and cable diameter is limited leading to power losses
Solution Approach 1:
The patent applies nesting by placing additional tubes and components inside the hollow interior of the cable rather than positioning them externally. The cable structure includes a hollow bore that accommodates pull-wires, guide-wires, and other components, allowing the cable to maintain a larger diameter for reduced power loss while integrating multiple functions within its volume.
2Adaptability or versatility
If conventional cables with additional tubes are used, then additional components can be provided, but the arrangement becomes complex with off-centre positioning
Solution Approach 1:
The cable is designed as a multi-functional universal structure where the hollow bore serves multiple purposes: it acts as the transmission medium for RF energy while simultaneously housing pull-wires, guide-wires, and other operational components. This unified design simplifies the overall arrangement by eliminating the need for separate external tubes and positioning mechanisms.
3Area of stationary object
If cable diameter is reduced to accommodate additional structures, then space efficiency improves, but power losses increase
Solution Approach 1:
The invention transitions from a two-dimensional arrangement where additional components are positioned externally around the cable to a three-dimensional configuration where components are nested within the hollow interior of the cable. This dimensional change allows the cable to maintain its full diameter for optimal power transmission while incorporating additional functionality within its volumetric space.
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 hollow cable design enhances power delivery to electrosurgical instruments by minimizing space requirements and improving actuation efficiency, reducing power losses and enhancing the operation of electrosurgical instruments.
Implementation Method 1
a cable for conveying radiofrequency and/or microwave frequency energy to an electrosurgical instrument... a hollow tube comprising inner and outer electrically conductive layers separated by dielectric material to form a transmission line
Implementation Method 2
such a hollow cable is achievable in practice because of the skin-depth effect when transmitting microwave frequency energy, which means that microwave frequency energy travels only in a shallow surface area of a conductor
Implementation Method 3
inner and outer electrically conductive layers separated by dielectric material to form a transmission line
Data Source
AI summary
Embodiments of the invention provide a hollow cable for transmitting radiofrequency and/or microwave frequency energy to an electrosurgical instrument, wherein the hollow cable is provided with electrical connectors for forming a bipolar electrical connection with an electrosurgical instrument that fits within, e.g. slides relative to, the hollow cable. The connectors can be conductive protrusions extending in an axial direction on opposite sides of the cable. The protrusions can be tabs, fins, rods, pins, or wires. The protrusions can be strips which engage corresponding terminals on the instrument. The transmission line structure of the invention can have a greater diameter then convention coaxial cables, which can minimise loss whilst still providing access for control wires and/or fluid to reach an surgical instrument. The cable can be used with multiple instruments.