Self-Expanding Cannula with Braided-Wire Body for Minimally Invasive Fluid Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cardiac cannulae with large diameters cause tissue and organ damage and complicate tunneling due to their size, making access to the heart and vessels difficult and invasive.
Innovation Solution
A self-expanding cannula with a braided-wire body covered by a flexible membrane, which can compress to a small diameter for minimally invasive insertion and expand to a larger diameter for fluid flow, reducing tissue trauma and facilitating easy access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a cannula with large diameter is used to provide sufficient fluid flow capacity, then the fluid flow capability is improved, but the tissue trauma and difficulty of tunneling increase
Solution Approach 1:
The cannula employs a self-expanding mechanism that transitions from a compressed low-diameter state during insertion to an expanded high-diameter state for fluid flow. The braided wire structure with flexible membrane allows dynamic diameter adjustment, resolving the contradiction between insertion size and flow capacity.
Solution Approach 2:
The cannula diameter is changed as a variable parameter - small during insertion phase, then expands to large diameter after positioning. This parameter change allows the same device to satisfy both minimally invasive insertion requirements and sufficient fluid flow requirements.
2Quantity of substance
If a cannula with large diameter is used to ensure adequate bore size, then the fluid flow capability is improved, but the complexity of tunneling and positioning increases
Solution Approach 1:
The dynamic diameter adjustment capability allows the cannula to be simple during insertion (compressed state) and then become complex only when needed for flow (expanded state), reducing overall tunneling complexity.
Solution Approach 2:
The cannula is inserted within a guiding catheter that is removed after positioning. The nested structure allows the cannula to be protected and guided during insertion, then deployed independently, simplifying the tunneling process.
3Ease of operation
If a self-expanding cannula is used to reduce insertion diameter, then the ease of insertion is improved, but the structural complexity increases
Solution Approach 1:
The flexible membrane covering the braided wire provides a smooth, compliant surface that facilitates easy insertion while maintaining the self-expanding structure. The thin film adds minimal complexity while enabling the dynamic diameter function.
4Object-affected harmful factors
If a compressed cannula is used for minimally invasive access, then the tissue trauma is reduced, but the fluid flow capacity is limited
Solution Approach 1:
The cannula diameter dynamically adapts to the operational phase: compressed for insertion (minimizing trauma) and expanded for fluid flow (maximizing capacity). This dynamic behavior resolves the contradiction between insertion invasiveness and flow capability.
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
Enables easy and conservative positioning of the cannula within the patient, minimizing tissue puncture and trauma, while providing a leak-tight conduit for fluid exchange, and can be tailored for specific applications such as blood pumps with auto-regulation of flow rates.
Implementation Method 1
The body of the self-expanding cannula is constructed from a braided-wire, so that the self-expanding cannula is capable of expanding from a closed diameter to an opened diameter
Implementation Method 2
a pre-determinable portion of the braided-wire is covered by a flexible membrane, which is preferably an elastomeric material creating a membrane-like structure enabling the braided-wire to articulate from the closed diameter to the opened diameter and the flexible membrane sealing an interstitial space resultant between the braid openings
Data Source
AI summary
A self-expanding cannula providing a conduit through a skin between an inside of a corpus and an outside of the corpus is disclosed. The self-expanding cannula includes a body encompassing a lumen, and has a distal-end to be positioned outside of the corpus for attachment to an extracorporeal fluid handling system and having a proximal-end to be positioned inside of the corpus, for attachment to an organ of an human or an animal. The body of the self-expanding cannula is constructed from a braided-wire, so that the self-expanding cannula is capable of expanding from a closed diameter to an opened diameter. A catheter-sheath and a catheter-sheath-assembly as well as to a method for applying and positioning a self-expanding cannula, and a catheter-sheath-assembly are disclosed.