Cryoprobe Heater and Movable Insulating Sleeve for Iceball Control

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Solution Overview

Problem

Existing cryoablation systems require secondary gases or fluids to warm the cryoprobe, adding complexity and cost, and there is a need for improved systems that can perform warming or heating without significant additional complexity or cost.

Innovation Solution

A cryoprobe with an adjustable insulating sleeve and a resistive heater that allows for heating the needle to predetermined temperatures, eliminating the need for secondary gases by using conduction or convection methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a second gas or fluid is used to warm the cryoprobe, then the cryoprobe can be warmed following a freezing cycle, but the system complexity and cost increase

Engineering Contradiction:
Improvecryoprobe warming capabilityVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent removes the second gas or fluid heating system from the cryoablation system, extracting the problematic component that added complexity. Instead, it uses the existing cryogen flow path and a controllable heater element integrated into the probe to achieve warming without requiring additional gases or fluids.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cryogen flow path is made multi-functional: it serves both the primary cooling function and the secondary warming function when reversed. The same conduit system that delivers cold cryogen can deliver warm cryogen or ambient temperature fluid to warm the probe, eliminating the need for separate heating systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If a second gas or fluid is used to warm the cryoprobe, then the cryoprobe can be warmed following a freezing cycle, but the system cost increases

Engineering Contradiction:
Improvecryoprobe warming capabilityVSAvoidsystem cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive, readily available materials for the heater element and insulation components. The heater is a simple resistive heating element that can be manufactured at low cost, and the insulation uses standard materials rather than expensive specialized components.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system uses the cryogen itself (or ambient temperature fluid) to warm the probe by reversing the flow direction, rather than requiring an external heating system. The existing cryogen circulation infrastructure serves the dual purpose of cooling and warming.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If an insulating sleeve is made adjustable, then the iceball size can be controlled, but the device complexity increases

Engineering Contradiction:
Improveiceball size controlVSAvoidprobe structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The insulating sleeve is made movable along the probe shaft rather than fixed, allowing dynamic adjustment of the insulated section length. This enables real-time control of iceball size by changing how much of the probe is thermally isolated from the tissue, with the sleeve positioned by a simple mechanical actuator.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The probe is divided into distinct functional sections: a heated section near the tip, an insulated section with adjustable length, and a non-insulated section. This segmentation allows independent control of thermal zones to precisely define iceball boundaries while using simple, modular components.

Inventive Principle:
Principle #1Segmentation

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

Enables efficient heating procedures, including cautery and track ablation, at temperatures greater than 80 degrees Celsius, reducing system complexity and cost while allowing precise control over iceball size.

Implementation Method 1

a resistive heater that can be used to perform a thaw, cautery, or track ablation procedure

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

The insulated sleeve may insulate the needle from the cryogen at a portion of the longitudinal length of the needle

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

The vacuum sleeve may be configured such that the hollow space inside the sleeve is manufactured to be at vacuum so as to prevent or reduce the transfer of thermal energy

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Implementation Method 4

Heat from the tissue passes from the tissue, through the probe, and into the cryogen that removes heat from the targeted tissue

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4702940A1Heaters for cryoablation probes with movable insulating sleeves
Publication Date: 2026.03.04 VARIAN MEDICAL SYSTEMS INC
  • EP4702940A1 patent drawingFigure 1
  • EP4702940A1 patent drawingFigure 2
  • EP4702940A1 patent drawingFigure 3

AI summary

A cryoprobe (300) includes a needle (304) defining an internal cavity, a cryogen conduit (308) positioned in the internal cavity, an adjustable insulating sleeve (302) positioned in the inner cavity radially outward of the cryogen conduit, and a heater (314) configured to heat the needle to predetermined temperature.