Nitinol Helical Coil Electrode Minimally Invasive Deployment
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Solution Overview
Problem
Existing RF ablation technologies face challenges in deploying helical coil electrodes minimally invasively into tissue without significant deformation or rotation, which affects the precision and effectiveness of tumor ablation.
Innovation Solution
A coil electrode constructed from shape memory alloys like Nitinol, with a specific geometry and deployment mechanism that includes a cannulating delivery needle and introducer sheath, is used to deploy the helical coil electrode into tissue, minimizing deformation and rotation through precise deployment and heat treatment to maintain shape and trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a helical coil electrode is deployed minimally invasively into tissue, then the invasiveness of the procedure is reduced, but the coil may deform or rotate affecting precision
Solution Approach 1:
The helical coil electrode is nested within a delivery needle and introducer sheath during storage and insertion. The coil is contained in a compressed state within the needle lumen, allowing minimally invasive access to the target tissue. Upon deployment, the coil expands to its intended helical shape while maintaining positional accuracy and orientation control.
Solution Approach 2:
The coil electrode utilizes shape memory alloy material that changes its physical properties in response to temperature changes. The coil is transformed from a compressed, low-volume state during insertion to an expanded, helical state at the target site through controlled thermal or mechanical activation, ensuring both minimally invasive delivery and precise final configuration.
2Ease of operation
If the coil electrode is made flexible for easy deployment, then ease of operation improves, but control over final position and orientation may be lost
Solution Approach 1:
The delivery system is segmented into distinct functional components: a flexible delivery needle for access, an introducer sheath for guidance, and the coil electrode itself. This segmentation allows each component to be optimized for its specific function while working together to achieve both flexible deployment and precise positioning control.
Solution Approach 2:
The introducer sheath acts as an intermediary between the delivery needle and the target tissue. It provides a stable, guided pathway that maintains control over the coil's final position and orientation while allowing the flexible coil to be deployed accurately at the intended location.
3Volume of moving object
If the coil expands significantly upon deployment, then it can cover larger tissue volume, but it causes more deformation and affects precision
Solution Approach 1:
The coil electrode transitions dynamically from a compressed, low-volume state during insertion to an expanded, high-volume helical state at the target site. This controlled dynamic transformation allows the coil to minimize deformation during delivery while maximizing treatment volume coverage once deployed, achieving both precision and effectiveness.
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 solution enables precise and efficient deployment of the helical coil electrode into liver and kidney tissue, achieving uniform electric fields for effective tumor ablation with minimal expansion and deformation, validated through ex vivo and in vivo testing, resulting in successful cell necrosis and reduced treatment time.
Implementation Method 1
The coil electrode may be constructed from a shape memory alloy such as Nitinol. The coil electrode may be heat treated to induce a martensitic structure
Implementation Method 2
provided with an excitation current having a frequency that is sufficient for magnetic induction and coupling of various electric and magnetic fields to produce an electric field within the volume surrounded by the coil for directly applying heat to the tissue therein
Implementation Method 3
produce an electric field within the volume surrounded by the coil for directly applying heat to the tissue therein
Data Source
AI summary
A coil electrode for use with an RFA (radio frequency ablation) apparatus, has a lead portion, and a helical portion coupled to the lead portion, the helical portion being formed of Nitinol SE510. Further, an RFA (radio frequency ablation) apparatus, comprises an applicator, the applicator including a handle and a cannulating delivery needle mounted to the handle, the cannulating delivery needle including a tip spaced apart from the handle. A coil electrode includes a lead portion housed in the cannulating delivery needle, and a helical portion coupled to the lead portion, the helical portion formed of Nitinol. The helical portion has a retracted state when housed within the cannulating delivery needle and a deployed state when moved out of the tip of the cannulating delivery needle.