Off-wall electrode device with spacer struts for nerve modulation
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Solution Overview
Problem
Current methods for intravascular nerve modulation, such as renal nerve ablation, often result in thermal injury to the vessel wall and other side effects like blood damage and clotting due to inadequate cooling during radio frequency ablation.
Innovation Solution
A system comprising a radially expandable member with electrodes and spacer struts that maintain a distance from the vessel wall, combined with an expandable occlusive member to increase blood flow velocity and convective cooling, and boundary layer control elements like trip struts to enhance heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radio frequency electrode is used for nerve ablation, then nerve function can be interrupted, but thermal injury to vessel wall and blood damage occur
Solution Approach 1:
A cooling fluid is introduced as an intermediary substance between the RF electrode and the vessel wall. The cooling fluid absorbs thermal energy from the electrode, preventing direct thermal contact with the vessel wall while allowing RF energy to continue ablating the nerve tissue. This mediator resolves the contradiction by enabling effective nerve ablation without transferring harmful thermal energy to the vessel wall.
Solution Approach 2:
The harmful thermal effect is extracted or separated from the useful nerve ablation function. By introducing dedicated cooling channels and fluid flow paths, the thermal management function is extracted as a separate system that independently controls heat transfer, allowing the RF electrode to focus on nerve ablation while the cooling system prevents vessel wall injury.
2Object-affected harmful factors
If cooling is increased during RF ablation, then thermal injury is reduced, but system complexity increases
Solution Approach 1:
The cooling system is merged with the existing RF catheter structure. Cooling channels are integrated into the catheter body, and cooling fluid delivery is combined with the RF energy delivery system. This integration allows thermal management to be achieved without adding separate external cooling equipment, thereby reducing overall system complexity while still providing effective cooling to prevent vessel wall injury.
Solution Approach 2:
The cooling system is designed to be self-regulating through passive heat exchange mechanisms. The cooling fluid naturally absorbs heat from the RF electrode through thermal conduction and convection, and the system uses the body's own blood flow as an additional cooling mechanism. This self-service approach reduces the need for complex active cooling control systems while maintaining effective thermal management.
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 effectively reduces thermal injury to the vessel wall and minimizes blood damage and clotting by increasing convective cooling and heat transfer during nerve ablation.
Implementation Method 1
Increased cooling in the region of the nerve ablation may reduce such undesirable side effects
Implementation Method 2
it may be desirable to ablate perivascular renal nerves using a radio frequency (RF) electrode
Implementation Method 3
the expandable member comprising a plurality of electrodes and a plurality of spacer struts, each spacer strut configured such that when the expandable member is in an expanded state the spacer strut extends out radially further than the electrodes
Data Source
AI summary
Systems for nerve modulation through the wall of a blood vessel are disclosed. An example system for nerve modulation may include an elongate member extending along a central elongate axis and having a proximal end and a distal end. The elongate member may have a radially expandable member disposed proximate the distal end. A tubular sheath may be cooperatively engaged with the expandable member such that the expandable member is collapsed when in the sheath and can expand when moved distally relative to and past a distal end of the sheath. The expandable member may include a plurality of electrodes and a plurality of spacer struts. Each spacer strut may be configured such that when the self-expanding member is in an expanded state the spacer strut extends out radially further than the electrodes from the central elongate axis.