Retrievable Access Valve Using Self-Expansion for Leak-Sealed Wall Access
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Solution Overview
Problem
Existing medical devices for accessing body cavities face challenges in providing reliable and retrievable access points that can maintain a seal without leakage, especially in difficult-to-locate areas, and often require removal after a limited time due to issues like gastric acid leakage.
Innovation Solution
An implantable access valve with a self-expandable member and elastic membrane that secures to a bodily wall, allowing controlled access and sealing, featuring a frame with a conical portion and a radially extending base to apply compressive forces, and a retrieval flange for easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a permanent access valve is implanted to provide long-term access, then the duration of action is improved, but reliability deteriorates due to gastric acid leakage and tissue irritation
Solution Approach 1:
The access valve is designed with a self-expanding frame that transitions from a compressed delivery state to an expanded implanted state, allowing the device to adapt dynamically to the tissue environment. The frame expands radially upon deployment to engage with the tissue wall, providing stable long-term fixation while maintaining sealing capability against gastric acid leakage.
Solution Approach 2:
The valve utilizes changes in physical parameters including the self-expanding frame's radial expansion, the elastomeric membrane's transition from compressed to expanded state, and the adjustable opening mechanism that changes the lumen diameter from closed to open positions. These parameter changes enable the valve to maintain reliability throughout the implantation duration by adapting to physiological conditions.
2Reliability
If the access valve is made retrievable to improve reliability, then device removal is enabled, but device complexity increases due to retrieval mechanisms
Solution Approach 1:
The access valve incorporates a self-expanding frame that automatically expands upon delivery to the target site, eliminating the need for complex external expansion mechanisms. The frame's self-expansion property also facilitates retrieval, as the device can be compressed back to its delivery configuration for removal. This self-service mechanism reduces overall device complexity while maintaining retrievability.
Solution Approach 2:
The valve is divided into distinct functional segments including the self-expanding frame, the elastomeric membrane, the opening mechanism, and the delivery sheath. This segmentation allows each component to be optimized independently, with the self-expanding frame providing both deployment and retrieval functionality without requiring additional complex mechanisms.
3Reliability
If the elastic membrane is made highly compliant to improve sealing, then sealing performance is improved, but manufacturing precision becomes more difficult
Solution Approach 1:
The access valve utilizes an elastomeric membrane as a flexible sealing element that conforms to the irregular tissue surface. The membrane's elasticity and compliance allow it to create an effective seal without requiring precise manufacturing tolerances. The flexible nature of the thin film enables it to adapt to physiological movements and tissue deformation while maintaining sealing integrity.
Solution Approach 2:
The valve employs composite construction combining a rigid or semi-rigid self-expanding frame with a flexible elastomeric membrane. This composite material approach allows the sealing function to be performed by the compliant membrane while the frame provides structural support and positioning, reducing the manufacturing precision requirements for the membrane itself.
4Force
If the frame is made rigid to apply compressive forces, then sealing force is improved, but ease of operation deteriorates during delivery
Solution Approach 1:
The self-expanding frame is designed to be compliant during delivery within the constraining sheath, allowing easy navigation and positioning. Upon deployment, the frame dynamically transitions to an expanded configuration that applies radial compressive forces against the tissue wall. This dynamic behavior enables the frame to be both easy to operate during delivery and effective at applying sealing forces during implantation.
Solution Approach 2:
The frame is delivered in a compressed state within the delivery sheath, similar to a nested doll configuration. This nesting allows the rigid or semi-rigid frame to be easily maneuvered through the delivery system without requiring complex articulation or flexibility mechanisms. The frame then expands from this nested configuration to apply compressive forces, combining ease of delivery with effective force application.
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
Facilitates periodic infusions and drainages with controlled access and sealing, reducing leakage and enabling multiple procedures without the need for repeated implantation, suitable for locations like the stomach and colon walls.
Implementation Method 1
a self-expandable member extending through the lumen of the frame and having a first end proximal of the first end of the frame and a second end distal of the second end of the frame
Implementation Method 2
an elastic membrane extending through the lumen and through the second end of the frame to releasably seal the lumen
Data Source
AI summary
Medical devices and methods for making and using medical devices are disclosed. An example medical device may include an access valve that may be retrieved after implantation. The access valve may include a frame having a lumen, a self-expandable member extending through the lumen, and an elastic membrane extending through the lumen and a second end of the frame to releasably seal the lumen. The access valve may releasably attach to a wall of a patient and releasably seal an opening through the wall. The access valve may be attached to the wall by placing the frame adjacent the wall, extending the self-expandable member through the opening in the wall, and expanding the self-expandable member such that the self-expandable member applies a first force against the wall and a second force opposite the first force against the frame to sandwich the wall between the self-expandable member and the frame.