Stent Delivery Catheter Segmentation for Precise Positioning
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Solution Overview
Problem
Existing stent placement systems, particularly for braided self-expandable stents, face challenges in achieving precise positioning due to drastic expansion and length changes, making it difficult to maintain a determined position after release within blood vessels.
Innovation Solution
A catheter system with a connecting means between the drive unit and the sluice, allowing synchronized or alternating movement of the middle and actuating units, which includes a telescopic or elastic connecting mechanism to control the stent's expansion and maintain its specified position, reducing friction and enabling precise placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a braided self-expandable stent is used, then the stent is more flexible and does not break after years in use, but the stent changes position dramatically upon release due to expansion and length changes, making precise positioning difficult
Solution Approach 1:
The catheter is divided into three concentric tubes (inner tube, middle tube, outer tube) that can move independently relative to each other. The stent is segmented along its length with expansion markers, allowing different sections to be positioned and expanded independently. This segmentation enables precise control of stent placement while maintaining the flexibility and durability of braided stent construction.
Solution Approach 2:
The system employs dynamic movement of the catheter tubes during the procedure. The inner tube can be advanced independently to position the distal end of the stent, while the middle and outer tubes remain stationary during expansion. This dynamic control allows the stent to be positioned precisely before expansion, and then expanded in place without causing dramatic position changes.
2Ease of operation
If the stent is radially compressed in a catheter to reduce cross-sectional area and increase length for insertion, then the stent can be inserted into the vessel with relative ease, but the stent cannot maintain its determined position after release
Solution Approach 1:
The stent is compressed to its insertion configuration before the procedure begins. The catheter is positioned with the compressed stent inside, and the distal end of the stent is aligned with the desired target position in the blood vessel. This preliminary positioning allows the stent to be inserted easily while maintaining the ability to achieve precise placement after expansion.
Solution Approach 2:
The three-concentric catheter structure acts as an intermediary mechanism between the compressed stent and the target position. The inner tube serves as a mediator that can be advanced independently to position the stent distal end, while the middle and outer tubes provide a stable framework for expansion. This intermediary structure enables both easy insertion and precise positioning.
3Productivity
If the middle tube is pushed distally to expand the stent, then the stent expands into its original shape, but the actuating unit and outer tube are pushed proximally, causing uncontrolled movement
Solution Approach 1:
The catheter is segmented into three independent tubes that can move relative to each other. The middle tube can be pushed distally to expand the stent while the inner and outer tubes remain stationary or move independently. This segmentation allows controlled expansion without uncontrolled proximal movement of the actuating unit.
Solution Approach 2:
The inner tube acts as an intermediary that couples the distal movement of the middle tube to the stent expansion while isolating the proximal actuating unit from uncontrolled movement. The inner tube transmits the expansion force from the middle tube to the stent while preventing the actuating unit from moving proximally during 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
Ensures the entire stent reaches its target length and specified position after release, with reduced friction and controlled movement, facilitating precise placement and expansion within the blood vessel.
Implementation Method 1
The drive unit cooperates with the middle tube in such a way that when the drive unit is operated the middle tube is pushed in a distal direction and the actuating unit, along with the attached outer tube, is pushed in a proximal direction
Implementation Method 2
it is possible for the inner tube to cooperate with the drive unit in such a way that it is shifted relative to the actuating unit and thus to the outer tube
Data Source
AI summary
A system comprising a sluice and a catheter. The catheter including an inner, a middle and an outer tube. A stent is disposed in a distal-end portion of the catheter between the inner and outer-tube. The middle-tube ends distally at the proximal end of the stent. An actuating unit having a drive unit provided in the proximal region of the catheter for releasing the stent. A connecting portion is provided between the drive unit and the sluice. The drive unit is cooperating with the middle-tube and the connecting portion where the drive unit is operated the middle-tube is displaced in the distal direction and the actuating unit together with the outer-tube attached thereto is displaced in the proximal direction. The inner-tube is cooperating with the middle-tube and/or the connecting portion and/or the drive unit in such a way that the inner-tube is displaced at least to some extent relative to the actuating unit.