Catheter Sleeve Segmentation for Stent Deployment Force Reduction
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Solution Overview
Problem
Current endoluminal delivery systems for expandable stents and stent grafts face challenges in compacting and deploying devices within the vasculature due to the need for precise radial constraining and releasing mechanisms, which can be cumbersome and require significant force.
Innovation Solution
A catheter assembly utilizing a single flexible sleeve with multiple releasable seams allows for selective axial and rotational positioning of expandable devices before full deployment, using a flexible constraining sleeve that maintains the device in an intermediate state until fully expanded, facilitating smoother deployment and engagement with vascular walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional constraining sheath is used to maintain the endoprosthesis in a compacted state, then the device can be delivered through the vasculature, but significant force is required to release and deploy the endoprosthesis
Solution Approach 1:
The constraining sheath is divided into multiple segments or sections along its length. Each segment can be independently released or detached, allowing the endoprosthesis to be deployed in a controlled, sequential manner rather than requiring simultaneous release of the entire sheath. This segmentation reduces the peak force needed for deployment by distributing the release process across multiple smaller actions.
Solution Approach 2:
The constraining sheath incorporates dynamic characteristics through its material composition and structural design, allowing it to transition from a rigid constraining state to a flexible released state. The sheath may include shape memory materials or phase-changing materials that respond to temperature or other environmental cues, enabling controlled deployment with reduced force requirements compared to static constraining mechanisms.
2Productivity
If the endoprosthesis is rapidly deployed from the delivery catheter, then the procedure is faster, but precise positioning and control during deployment is compromised
Solution Approach 1:
The delivery system is designed to pre-position the endoprosthesis and associated deployment mechanisms at the target site before actual deployment occurs. The catheter system includes positioning features such as markers, radiopaque elements, or navigation capabilities that allow the operator to accurately locate the device beforehand. This preliminary positioning ensures that when rapid deployment occurs, the endoprosthesis is already at the correct location, maintaining precision without sacrificing speed.
Solution Approach 2:
The deployment process utilizes periodic or staged action rather than a single continuous motion. The endoprosthesis can be deployed in controlled stages or with periodic pulses of expansion force, allowing brief pauses or controlled intervals during which positioning can be verified and adjusted if needed. This periodic deployment maintains both speed and precision by breaking the rapid deployment into manageable phases.
3Device complexity
If a non-corrugated constraining sheath is used, then the structure is simpler, but the release process requires more maximum force and is less smooth
Solution Approach 1:
The constraining sheath incorporates corrugations or curved structural features along its length, creating a series of expansion zones that facilitate gradual release. These corrugations act as mechanical advantage points that distribute the release force across multiple expansion zones rather than requiring single-point force application. The curved geometry of the corrugations allows for smoother deformation during release, reducing the peak force required while maintaining structural integrity during delivery.
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 approach enables more precise and efficient deployment of expandable devices within the vasculature, reducing the force required for release and allowing for better engagement with vascular tissue, thus improving the minimally invasive nature of endoluminal therapies.
Implementation Method 1
The endoprosthesis is designed to spontaneously dilate (i.e., elastically recover) or to be balloon-expanded from their delivery diameter
Implementation Method 2
They are designed to spontaneously dilate (i.e., elastically recover) or to be balloon-expanded from their delivery diameter
Implementation Method 3
to be balloon-expanded from their delivery diameter
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3c
AI summary
A catheter assembly includes a single sleeve that constrains an expandable device to a dimension suitable for endoluminal delivery of the device to a treatment site, and further allows expansion of the device toward an outer peripheral dimension that is smaller than a fully deployed outer peripheral dimension to allow positioning of the device at the treatment site prior to full deployment and expansion of the device at the treatment site.