Nitinol Wire Detachment Mechanism for Endovascular Devices
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Solution Overview
Problem
Current endovascular detachment mechanisms, such as mechanical, chemical, and electrolytic systems, face limitations in reliability, versatility, and safety during vascular procedures, particularly in detaching embolic devices from catheters without causing tissue damage or premature detachment.
Innovation Solution
A general endovascular electrical detachment mechanism using a nitinol wire wrapped around the detachable tip, which loosens with thermal energy caused by an applied current, allowing for atraumatic and on-demand release of the detachable tip component from the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical detachment systems are used to detach the tip from the catheter body, then the detachment can be achieved with a controlled breakage threshold, but excessive tensile force is transmitted through the joint causing tissue damage, vessel shifting, and potential avulsion
Solution Approach 1:
The patent replaces the mechanical detachment system with an electrical detachment system. Instead of using tensile force to break a mechanical joint, the invention uses electrical current to heat a section of the catheter body at the detachment zone, causing thermal expansion that triggers detachment. This substitution eliminates the transmission of harmful mechanical forces to the tissue while maintaining reliable detachment control.
Solution Approach 2:
The patent changes the detachment mechanism from a mechanical force-based system to a thermal energy-based system. By applying electrical current to heat the detachment zone, the physical state of the catheter material changes (thermal expansion), which triggers the detachment. This parameter change from mechanical force to thermal energy resolves the contradiction by eliminating tissue-damaging forces while preserving detachment reliability.
2Ease of operation
If tensile force is applied to detach the tip mechanically, then the detachment can be controlled, but the catheter body attempts to straighten out relative to the points of attachment putting excess strain on the vasculature
Solution Approach 1:
The patent replaces the mechanical force transmission system with an electrical heating system. Instead of pulling the catheter to detach the tip, electrical current is applied to heat the detachment zone, causing thermal expansion that triggers detachment. This eliminates the catheter straightening effect and excess strain on vasculature while maintaining ease of operation through electrical control.
3Object-affected harmful factors
If the minimum detachment force is set too low to avoid tissue trauma, then tissue damage is reduced, but premature tip detachment occurs leading to foreign body deposition in the vasculature
Solution Approach 1:
The patent changes the detachment trigger from a low-force mechanical threshold to a controlled thermal energy threshold. Electrical current applied to the detachment zone creates localized heating that causes thermal expansion, triggering detachment only when the intended amount of energy is delivered. This eliminates premature detachment while avoiding tissue trauma, as the thermal effect is localized and controllable.
4Object-affected harmful factors
If chemical detachment mechanisms using dissolvable adhesive are used, then very little force is needed to detach the tip, but the system is considerably less reliable than mechanical systems
Solution Approach 1:
The patent replaces chemical detachment mechanisms with an electrical-thermal detachment system. Instead of relying on dissolvable adhesive that may be unreliable, the invention uses controlled electrical heating to trigger predictable thermal expansion at the detachment zone. This provides both the low force transmission advantage of chemical systems and the reliability of a controlled physical mechanism.
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 solution provides a safer, more reliable, and versatile detachment method that reduces the risk of tissue damage and premature detachment, enabling effective embolization procedures with minimal strain on vessels and improved procedural outcomes.
Implementation Method 1
loosens with thermal energy caused by an applied current
Implementation Method 2
A general endovascular electrical detachment mechanism using a nitinol wire wrapped around the detachable tip, which loosens with thermal energy caused by an applied current
Data Source
AI summary
An endovascular device includes a catheter and a detachment mechanism that comprises a shape memory material located at a distal end of the catheter. The device further includes a detachable tip component secured by the detachment mechanism, wherein the detachment mechanism is configured such that application of electricity to the detachment mechanism causes the detachment mechanism to open and release the detachable tip component.