Stent With Selective Membrane Coating for Anti-Migration
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Solution Overview
Problem
Stents designed for implantation in body lumens, particularly in gastrointestinal and biliary tracts, face challenges with migration due to peristalsis and the moist, lubricious environment, which complicates procedures like hepaticogastrostomy and gastrojejunal bypass, as they lack both drainage and anti-migration features.
Innovation Solution
The design incorporates a tubular scaffold with a folded-over portion and a membrane that allows tissue ingrowth, providing a structure for anchorage and leak-free drainage, with varying configurations of covered and uncovered portions to balance drainage and anti-migration capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If stents are designed to be compressible and flexible for delivery, then ease of delivery is improved, but stent migration tendency increases
Solution Approach 1:
The stent is divided into multiple regions with different membrane coverage: distal and proximal anchor zones with extensive membrane coverage for tissue ingrowth and stability, and a central drainage zone with reduced or no membrane coverage for fluid passage. This segmentation allows simultaneous achievement of delivery flexibility and migration resistance.
Solution Approach 2:
Different portions of the stent are assigned different functional properties: the distal and proximal ends have high membrane coverage to promote tissue ingrowth and anchorage, while the medial region has reduced membrane coverage to maintain drainage functionality. This local differentiation resolves the contradiction between stability and drainage.
2Reliability
If stents are designed with membrane coating for leak-free drainage, then drainage functionality is improved, but tissue ingrowth and anti-migration capability deteriorate
Solution Approach 1:
The membrane coating is segmented to cover only specific regions (distal and proximal anchor zones) while leaving other regions (medial drainage zone) exposed. This allows the stent to provide leak-free drainage where needed while permitting tissue ingrowth in anchor zones for anti-migration capability.
Solution Approach 2:
The stent features local quality variation in membrane coverage: high coverage at distal and proximal ends for drainage and anchorage, and reduced coverage in the medial region for tissue ingrowth. This resolves the contradiction between drainage reliability and tissue integration.
3Stability of the object's composition
If stents are designed with full membrane coverage for anti-migration, then stent stability is improved, but drainage capability deteriorates
Solution Approach 1:
The membrane coverage is segmented rather than continuous, with covered distal and proximal regions for stability and an uncovered medial region for drainage. This segmentation enables the stent to maintain stability through tissue ingrowth while preserving drainage capability in the exposed region.
Solution Approach 2:
The stent implements local quality differentiation where membrane coverage is applied at distal and proximal ends for anti-migration while the medial region remains uncovered for fluid passage. This resolves the contradiction between stent stability and drainage productivity.
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 solution effectively reduces stent migration by promoting tissue ingrowth and maintaining drainage functionality, ensuring the stent remains in place while allowing fluid passage between anatomical structures.
Implementation Method 1
the folded-over portion extends from the distal end region toward the proximal end region
Implementation Method 2
a membrane disposed along the at least a portion of the medial region of the tubular scaffold
Data Source
AI summary
Medical devices and methods for using medical devices are disclosed. An example expandable medical device includes a tubular scaffold including an inner surface, an outer surface, a proximal end region, a distal end region, and a medial region extending between the proximal end region and the distal end region, wherein the tubular scaffold defines a folded-over portion, and wherein the folded-over portion extends from the distal end region toward the proximal end region. Further, the medical device includes a membrane disposed along the at least a portion of the medial region of the tubular scaffold.