Flexible Fluid-Cooled Shaft for Electrosurgical Cable Heat Management
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Solution Overview
Problem
Current microwave ablation devices are not suitable for accessing lesions in hard-to-reach locations during open surgical procedures, as the cable assembly can cause unwanted heat transfer and is not flexible enough to navigate between closely spaced tissue structures.
Innovation Solution
An energy-delivery device with a flexible, fluid-cooled shaft that contains the cable assembly and is designed for open surgical applications, featuring an antenna assembly with a dielectric material and a coolant system to prevent heat transfer and facilitate precise energy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cable assembly is used to transmit microwave energy from the generator to the instrument, then energy transmission is achieved, but the cable assembly causes unwanted heat transfer and is not flexible enough to navigate between closely spaced tissue structures
Solution Approach 1:
A flexible, fluid-cooled shaft is introduced as an intermediary component between the cable assembly and the antenna. This shaft contains the cable assembly within its structure and uses circulating fluid to cool the cable, preventing heat transfer to the patient while maintaining the cable's energy transmission function. The shaft itself becomes the new interface with the patient that is thermally safe.
Solution Approach 2:
The cable assembly is nested within the flexible shaft structure. The shaft comprises an inner tube containing the cable assembly, with cooling fluid flowing between the inner tube and an outer tube. This nested configuration protects the cable from direct patient contact while enabling flexible navigation through tissue.
2Adaptability or versatility
If the cable assembly is made more flexible to navigate hard-to-reach areas, then accessibility to lesions is improved, but heat transfer control becomes more difficult
Solution Approach 1:
A fluid cooling system is integrated into the shaft structure, with cooling fluid circulating through the annular space between the inner and outer tubes. This hydraulic cooling mechanism actively removes heat from the cable assembly, enabling the shaft to be flexible and elongated without compromising thermal safety. The fluid flow rate and temperature can be controlled to manage heat transfer precisely.
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 flexible, fluid-cooled shaft allows for safe and precise energy delivery to hard-to-reach areas, reducing heat transfer to the patient and enabling effective tissue ablation while maintaining control over temperature distribution.
Implementation Method 1
a flexible, fluid-cooled shaft... adapted to remove heat along the length of the cable assembly during delivery of energy
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3
AI summary
A device for cooling a cable assembly for use in an electrosurgical system comprises a housing (450) defining a fluid inlet chamber (462), a fluid outlet chamber (463), and an aperture for receiving a cable assembly therethrough. A tubular sleeve member (489) extends from a distal portion of the housing. The device further has a flexible fluid-cooled shaft (410) including: an inlet sleeve (431); an outlet sleeve (435); an inner tubular member (441) coaxially disposed about and slideably coupled to the inlet sleeve; and an outer tubular member (445) coaxially disposed about and slideably coupled to the outlet sleeve. The flexible fluid-cooled shaft (410) is in fluid communication with the inlet chamber (462) and the outlet chamber (463) of the housing, and the tubular sleeve member (489) is configured to house a portion of the flexible fluid-cooled shaft (410).