Cryoprobe Flow Restriction for Ablation Tip Temperature Control
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Solution Overview
Problem
Existing cryoprobes face challenges in regulating cryogen pressure at the ablation tip, leading to inconsistent temperature control and potential undesired cold exposure, and difficulty in accessing and ablating specific tissues effectively.
Innovation Solution
The cryoprobe design includes a malleable shaft with a fluid supply and exhaust conduit system, featuring a flow restricting element and insulating conduit, allowing for precise temperature regulation and targeted tissue ablation by varying the cross-sectional area of fluid flow and incorporating a flexible insulated conduit for thermal insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cryogen exhaust stream back pressure varies, then the temperature at the ablation tip varies substantially, but this leads to inconsistent temperature control
Solution Approach 1:
The patent applies parameter changes by systematically varying the cross-sectional area of the exhaust conduit to regulate back pressure. The exhaust conduit includes a proximal section with a first cross-sectional area and a distal section with a second cross-sectional area that is smaller than the first, creating a flow restriction that stabilizes back pressure and consequently stabilizes the ablation tip temperature.
2Temperature
If the ablation tip is cooled to extremely cold temperatures for effective ablation, then tissue ablation is achieved, but other portions of the cryoprobe may be exposed to undesired cold temperatures
Solution Approach 1:
The patent applies local quality by providing thermal insulation specifically at the distal end of the shaft where the ablation tip is located, while leaving other portions of the shaft uninsulated. The insulating conduit surrounds only the distal ablation section, allowing the tip to reach extremely cold temperatures for effective ablation while preventing heat loss from other portions of the probe that would cause undesired cold exposure.
3Temperature
If the cross-sectional area of the exhaust conduit is reduced to increase back pressure, then temperature regulation improves, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the exhaust conduit into distinct sections with different cross-sectional areas. The exhaust conduit is segmented into a proximal section with a larger cross-sectional area and a distal section with a smaller cross-sectional area, allowing independent optimization of each section's function while maintaining overall system simplicity.
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 design enables precise temperature control at the ablation tip while maintaining other parts of the probe at warmer temperatures, facilitating effective tissue ablation and reducing unwanted cold exposure, and enhances the ability to engage and ablate tissues like intercostal nerves.
Implementation Method 1
a flow restricting element in fluid communication with the fluid exhaust conduit, the flow restricting element regulating the flow of fluid through at least a portion of the fluid exhaust conduit
Implementation Method 2
incorporating a flexible insulated conduit for thermal insulation
Data Source
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AI summary
Cryosurgical devices, such as cryosurgical probes (cryoprobes) are disclosed. Some example embodiments may include an elongated shaft at least partially housing or delineating a fluid supply conduit and a fluid exhaust conduit, the elongated shaft including a distal ablation section terminating at a closed distal end, a housing at least partially circumscribing at least a portion of a proximal end of the elongated shaft and receiving or delineating at least a portion of the fluid supply conduit and a portion of the fluid exhaust conduit; and/or a flow restricting element in fluid communication with the fluid exhaust conduit, the flow restricting element regulating the flow of fluid through at least a portion of the fluid exhaust conduit.