Cryogenic Balloon Ablation with Liquid Spray Dispersion
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Solution Overview
Problem
Current tissue ablation techniques for treating Barrett's esophagus face challenges in achieving precise control over the ablation surface area and depth to effectively destroy Barrett's columnar epithelium without damaging underlying tissues or missing affected areas, leading to potential complications such as stricture formation and residual cancer cells.
Innovation Solution
A cryogenic tissue ablation instrument featuring a flexible body with a pressurized coolant supply and an expandable balloon that uses coolant dispersion apertures to create a uniform cooling effect on the balloon wall, allowing for controlled tissue ablation with precise temperature regulation and visualization, ensuring uniform tissue destruction up to 500 microns deep without harming deeper tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid nitrogen is sprayed directly onto esophageal wall tissue, then tissue ablation is achieved, but precise control over ablation depth and surface area is difficult to achieve
Solution Approach 1:
A balloon is introduced as an intermediary between the coolant source and the tissue. The balloon receives pressurized liquid nitrogen through a supply lumen, allows it to evaporate inside the balloon chamber, and transfers the cold temperature uniformly through its wall to the tissue surface. This mediator enables precise depth control (approximately 500 microns) while simplifying the overall delivery system compared to direct spray methods.
Solution Approach 2:
The balloon is constructed from a thin-walled compliant material that allows uniform thermal transfer from the interior cold environment to the exterior tissue surface. The thin film structure ensures efficient heat conduction while maintaining balloon flexibility for proper tissue contact, achieving uniform ablation across the treatment surface area.
2Reliability
If high temperature ablation is used to destroy Barrett's cells, then effective tissue destruction is achieved, but damage to underlying submucosa tissue and surrounding healthy tissue occurs
Solution Approach 1:
The system utilizes the phase transition of nitrogen from liquid to gas as the cooling mechanism. Pressurized liquid nitrogen is delivered through the supply lumen, evaporates inside the balloon chamber absorbing heat, and the resulting cold gas circulates within the balloon. This phase change enables reliable tissue destruction at controlled depths while the balloon containment prevents harmful effects on deeper submucosa and surrounding healthy tissues.
3Manufacturing precision
If the ablation therapy does not uniformly encompass all affected tissue areas, then Barrett's cells may be missed, but increasing treatment coverage may damage healthy surrounding tissue
Solution Approach 1:
The balloon is designed with a treatment region that has specific local properties - a defined length along the balloon axis that corresponds to the affected tissue area. The coolant supply lumen and balloon geometry are configured to provide uniform cooling specifically across this treatment region, ensuring complete coverage of Barrett's cells (up to 8 cm length) while maintaining precise boundaries that protect surrounding healthy tissue from unnecessary exposure.
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 system achieves uniform tissue ablation with controlled cooling, effectively destroying Barrett's cells while minimizing damage to deeper tissues, as demonstrated by computer simulations and temperature monitoring, ensuring effective treatment of esophageal wall tissue.
Implementation Method 1
a pressurized flowable coolant in the supply lumen will enter the balloon interior through the dispersion apertures in the form of a liquid spray that contacts and provides (through rapid evaporation) substantially uniform cooling of the interior balloon wall surface
Implementation Method 2
provides substantially uniform cooling of the interior balloon wall surface of a treatment region of the balloon
Data Source
Figure 1A~1C
Figure 2~4A
Figure 5~6
AI summary
Cryogenic tissue ablation instruments for treating body tissue include an elongate flexible body with a proximal supply port for coupling with a pressurized coolant a supply lumen in fluid communication with the proximal supply port, and an expandable cryogenic balloon carried on a distal portion of the elongate body. A dispersion member coupled to a distal end portion of the elongate body has an interior lumen in fluid communication with the supply lumen, the dispersion member having one or more coolant dispersion apertures in fluid communication with the balloon interior and sized and located with respect to the balloon wall such that a pressurized flowable coolant in the supply lumen enters the balloon interior as a liquid spray that provides (through rapid evaporation) substantially uniform cooling of an interior wall surface of the balloon.