Stent with Biodegradable Gripping Material for Migration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Medical stents designed to treat body lumens face challenges in maintaining position due to flexibility and radial force, leading to migration, and are difficult to remove once tissue has anchored, as bare stents reduce migration but are hard to extract, while covered stents are more prone to migration.
Innovation Solution
An expandable scaffold with a covered region to facilitate removal and a non-covered region for tissue ingrowth, featuring a biodegradable gripping material that prevents initial migration until securement via tissue ingrowth, allowing for temporary anchoring and eventual degradation for easy retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bare metal portions of the stent are exposed to tissue to promote tissue ingrowth and anchor the stent, then stent migration is reduced, but the stent becomes more difficult to remove once deployed
Solution Approach 1:
The stent is divided into multiple segments with different surface treatments: bare metal portions that promote tissue ingrowth for anchoring, and coated portions that prevent tissue adhesion for ease of removal. This segmentation allows different regions to fulfill conflicting functions simultaneously.
Solution Approach 2:
Different portions of the stent are given different local properties: some areas have bare metal surfaces to encourage tissue integration and stability, while other areas have anti-adhesive coatings to facilitate removal if needed. This local differentiation resolves the contradiction between anchoring and removability.
2Ease of operation
If the stent is designed with sufficient flexibility for delivery, then the stent can be easily implanted, but the stent has a tendency to migrate from its deployed position
Solution Approach 1:
The stent is designed with inherent flexibility that enables easy delivery and deployment, and simultaneously incorporates features (such as radial force elements and tissue-engaging structures) that are activated upon deployment to prevent migration. The preliminary design ensures both deliverability and subsequent stability.
Solution Approach 2:
The stent transitions from a flexible, compressible state during delivery to a rigid, stable state after deployment. The dynamic transformation allows the stent to be flexible during implantation but stable in its final position, resolving the contradiction between ease of delivery and position stability.
3Ease of operation
If a covering is applied to the stent to create a physical barrier and reduce tissue anchoring, then the stent is easier to remove, but the stent becomes more prone to migration
Solution Approach 1:
The stent surface is segmented into coated and uncoated regions, allowing simultaneous achievement of ease of removal (via coated portions) and stent anchoring (via uncoated portions that promote tissue ingrowth).
Solution Approach 2:
Different local regions of the stent have different properties: coated areas provide anti-adhesive characteristics for easy removal, while uncoated areas provide tissue integration for stability. This local quality differentiation resolves the contradiction between removability and anchoring.
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 design effectively reduces stent migration while enabling easy removal and repositioning by using a biodegradable material that secures the stent until tissue ingrowth anchors it, then degrades to allow for stent extraction.
Implementation Method 1
the second region is secured to the inner surface of the body lumen via tissue ingrowth into the interstices of the second region
Implementation Method 2
the gripping material is biodegradable... designed to initially prevent migration of the expandable scaffold upon implantation in the body lumen until the second region is secured to the inner surface of the body lumen via tissue ingrowth
Data Source
AI summary
An example medical device for treating a body lumen is disclosed. The medical device includes an expandable scaffold including first and second regions, each of the first and second regions include a plurality of interstices located therein. The medical device also includes a covering spanning each of the plurality of interstices of the first region. The second region is free of the covering. A biodegradable gripping material is disposed on an outer surface of the covering. Further, the expandable scaffold is configured to shift from a collapsed state to an expanded state and the second region is configured to contact an inner surface of the body lumen in the expanded state. Additionally, the gripping material is designed to initially prevent migration of the expandable scaffold upon implantation in the body lumen until the second region is secured to the inner surface of the body lumen.