Cryoablation Probe Distal Tip Sealing for Tortuous Anatomy
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Solution Overview
Problem
Cryoprobes with rigid shafts are not suitable for navigating tortuous passageways in the human anatomy during cryosurgery, leading to potential fluid leakage and reduced robustness.
Innovation Solution
A cryoablation probe with a distal tip structure that includes a compressive element, such as a swage ring or fibrous compressive wrap, to enhance the seal between the distal tip and cryoablation shaft, incorporating mechanical features that facilitate a robust seal and reduce fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid shaft is used in the cryoprobe, then the structural strength and seal reliability are improved, but the ability to navigate tortuous passageways deteriorates
Solution Approach 1:
The shaft is divided into multiple segments including a proximal rigid shaft portion and a distal flexible shaft portion. This segmentation allows the proximal portion to provide structural strength while the distal portion provides flexibility for navigating tortuous passageways, thereby resolving the contradiction between strength and adaptability.
Solution Approach 2:
Different portions of the shaft are assigned different mechanical properties: the proximal shaft is made rigid for structural support, while the distal shaft is made flexible for navigation. This local differentiation of quality allows each portion to optimize its function, resolving the contradiction between overall strength and local adaptability.
2Reliability
If a rigid shaft is used in the cryoprobe, then the robustness of the device is improved, but the risk of fluid leakage increases due to inability to navigate complex pathways
Solution Approach 1:
The shaft is segmented into rigid and flexible portions, allowing the flexible distal portion to conform to tortuous passageways while maintaining seal integrity. This prevents fluid leakage by ensuring proper alignment and contact between sealing surfaces, even when navigating complex anatomical pathways.
Solution Approach 2:
The distal flexible shaft portion acts as a flexible element that can bend and conform to the shape of tortuous passageways. This flexibility ensures that sealing surfaces remain in proper contact, preventing fluid leakage while maintaining device robustness through the segmented design.
3Adaptability or versatility
If a flexible distal shaft portion is added to enable navigation of tortuous passageways, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The shaft is divided into two main segments: a proximal rigid portion and a distal flexible portion. This segmentation provides a straightforward structural solution that enables navigation of tortuous passageways without requiring complex mechanisms, thereby achieving adaptability with minimal increase in device complexity.
4Reliability
If a distal tip structure with compressive element is added to improve sealing, then the seal reliability is improved, but the device complexity increases
Solution Approach 1:
A compressive element in the form of a flexible ring is added to the distal tip structure. This ring applies continuous compressive force to maintain sealing between the shaft and surrounding tissue or components, improving seal reliability through a simple yet effective mechanical means without significantly increasing overall device complexity.
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 distal tip structure improves the robustness of the cryoprobe, minimizing fluid leakage and enhancing its ability to navigate complex anatomical pathways during cryosurgery.
Implementation Method 1
a cryoprobe uses the Joule-Thomson effect to produce cooling or heating of the probe tip. In such cases, the expansion of a cryofluid in the cryoablation probe from a higher pressure to a lower pressure leads to cooling of the device tip to temperatures at or below those corresponding to cryoablation a tissue in the vicinity of the tip.
Implementation Method 2
Heat transfer between the expanded cryofluid and the outer walls of the cryoprobe leads to formation of an ice ball, in the tissue around the tip and consequent cryoablation of the tissue.
Data Source
AI summary
In an embodiment, a cryoablation probe includes a shaft, where the shaft has a supply tube, a return tube surrounding the supply tube, an insulated portion, wherein a vacuum circuit runs through the insulated portion between the return tube and an insulating shaft, and an expansion chamber extending distally to the insulated portion. The probe further includes a distal tip configured to seal a distal end of the return tube. The distal tip has a tip portion extending distally from the distal end of the return tube and a plug portion configured to be inserted inside of the return tube. The probe includes a compressive element surrounding the return tube and the plug portion of the distal tip, configured to seal the distal tip to the return tube.