Tacky Silicone Coating Prevents Stent Migration
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Solution Overview
Problem
Stent migration remains a challenge after deployment, particularly for fully covered stents, which are prone to movement in body lumens due to their flexible and compressible properties, necessitating a solution to prevent displacement from the treatment site.
Innovation Solution
A stent with a tacky biocompatible coating, such as tacky silicone or polymeric materials with peel adhesion between 20 to 50 grams per inch, is deployed, which adheres gently to the vessel wall without compromising adhesion in moist environments, preventing stent migration by hindering movement post-deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stent is made flexible and compressible to facilitate delivery through body lumens, then ease of delivery is improved, but the stent becomes prone to migration from the treatment site
Solution Approach 1:
A tacky coating is applied to the stent surface before delivery, which remains inactive during compression and delivery but activates after deployment to prevent migration. This preliminary preparation allows the stent to be delivered in a flexible state while gaining migration resistance after placement.
Solution Approach 2:
The coating material undergoes a change in adhesive properties from low adhesion during delivery to high adhesion after deployment. This parameter change allows the stent to be easily delivered while subsequently resisting migration through enhanced surface adhesion.
2Reliability
If a stent is made rigid to prevent migration, then stent migration resistance is improved, but the stent cannot conform to tortuous body lumens during delivery
Solution Approach 1:
The stent structure is divided into the metallic framework and the separate coating layer. The framework provides rigidity for migration resistance, while the coating layer provides conformability during delivery and activates adhesion after deployment.
Solution Approach 2:
The stent combines a metallic structure with a polymeric tacky coating. The metal framework provides structural integrity and rigidity, while the polymer coating provides flexibility during delivery and adhesive properties to prevent migration after deployment.
3Reliability
If barbs or flares are added to the stent to prevent migration, then stent migration resistance is improved, but device complexity increases
Solution Approach 1:
The migration prevention function is extracted from the stent structure itself and implemented through a separate coating layer. This eliminates the need for structural modifications like barbs or flares, maintaining stent simplicity while achieving migration resistance.
Solution Approach 2:
The tacky coating acts as an intermediary between the stent and the vessel wall, providing migration resistance without requiring direct structural modifications to the stent. This mediator layer simplifies the overall device design compared to integrated mechanical anchoring features.
4Reliability
If clips or sutures are used to attach the stent to the vessel wall, then stent migration resistance is improved, but ease of operation and procedure time are worsened
Solution Approach 1:
The stent coating automatically adheres to the vessel wall after deployment without requiring external attachment devices or procedures. The self-adhering coating eliminates the need for clips, sutures, or other manual attachment methods, simplifying the deployment process.
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 tacky coating effectively reduces stent migration by providing a gentle, non-permanent adhesion that remains effective in moist conditions, ensuring the stent remains in place while allowing for easy removal when necessary.
Implementation Method 1
a tacky biocompatible coating comprising a tacky silicone... adheres gently to the vessel wall without compromising adhesion in moist environments
Data Source
AI summary
A stent having an inner surface and an outer surface, at least a portion of the outer surface of the stent comprising a tacky biocompatible coating comprising a tacky polymer material and to methods of delivering and deploying a stent using a tacky biocompatible coating comprising a tacky polymer material.