Retractable Wire Stent Delivery System
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Solution Overview
Problem
Existing stent delivery systems often employ cumbersome and bulky deployment mechanisms, and there is a need for medical devices that can be retained on a catheter with a retractable member of minimal profile.
Innovation Solution
A delivery system featuring a catheter with a retractable retaining wire or flexible members that retain an expandable medical device in a reduced configuration, allowing for minimal profile delivery and expansion when needed, using a pull-wire mechanism and various configurations such as coiled wires or internal engagement members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retractable sheath is used to protect and deliver the stent, then the stent is protected during delivery, but the deployment mechanism becomes cumbersome and bulky
Solution Approach 1:
The patent extracts the protective function from a traditional retractable sheath and implements it through a simpler balloon-protective member assembly. The sheath is removed entirely, and protection is achieved through the balloon itself and a minimal protective member at the distal end, significantly simplifying the deployment mechanism while maintaining stent protection during delivery.
Solution Approach 2:
The patent uses a thin-film protective member disposed over the distal end of the balloon that can be easily retracted or removed. This flexible thin film provides necessary protection during delivery without the bulk and complexity of a traditional sheath-based system, allowing for simpler deployment mechanics.
2Reliability
If a traditional retractable sheath system is used, then the stent can be protected, but the profile of the delivery catheter increases
Solution Approach 1:
The patent removes the traditional sheath component entirely, reducing the delivery catheter profile. Protection is achieved through the balloon and a minimal protective member, eliminating the need for a bulky sheath that would increase the catheter's length and cross-sectional profile.
Solution Approach 2:
The protective member is nested within or integrated with the balloon structure, allowing it to be contained within the delivery catheter profile during delivery. This nesting approach minimizes the overall catheter size while maintaining protection capabilities.
3Ease of operation
If self-expanding stents are used, then the stent can expand automatically upon sheath removal, but the sheath must be bulky to adequately restrain the stent
Solution Approach 1:
The patent eliminates the need for a bulky restraining sheath by using the balloon itself as the restraint mechanism. The balloon maintains the stent in a compressed state during delivery and can be deflated and removed to allow automatic stent expansion, simplifying the restraint mechanism while maintaining ease of operation.
Solution Approach 2:
The patent replaces the mechanical sheath-based restraint system with a pneumatic system using the balloon. The balloon's inflation and deflation provide the restraining and releasing functions, eliminating the need for complex mechanical sheath retraction mechanisms and allowing for simpler automatic stent expansion.
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 and compact deployment of expandable medical devices, reducing the bulkiness of deployment mechanisms and allowing for precise control over the expansion of stents within the body.
Implementation Method 1
Self-expanding stents may be made of shape memory metals such as nitinol
Data Source
AI summary
A medical device delivery system comprises a catheter having a catheter shaft with a proximal region and a distal region. The catheter shaft has a pull wire lumen therein. An expandable medical device is disposed about medical device receiving region of the catheter shaft. The expandable medical device has a reduced configuration and an expanded configuration. The system further comprises a retractable retaining wire, at least a portion of which is coiled about the expandable medical device and retains the expandable medical device in the reduced configuration. One end of the retractable retaining wire terminates in a pull-wire. The pull-wire extends into the pull-wire lumen to the proximal region of the catheter shaft.