Introducer Collars for Controlled Medical Device Deployment
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Solution Overview
Problem
Existing introducer assemblies for deploying implantable medical devices face challenges in ensuring precise positioning due to the uncontrolled expansion of self-expanding devices, which can lead to deployment difficulties, especially when multiple devices with varying shapes and dimensions need to be accommodated.
Innovation Solution
An introducer assembly with an elongate carrier element featuring collars with a larger diameter than the carrier, equipped with restraining elements such as bores or recesses to securely hold restraining wires, allowing for sequential release and controlled expansion of medical devices along their length, including intermediate points for enhanced placement control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-expanding medical devices are released from the introducer assembly, then the device can be deployed into the patient, but the device springs out of its constrained configuration causing uncontrolled movement and positioning difficulties
Solution Approach 1:
The introducer assembly is divided into multiple collars (first collar, second collar, and intermediate collars) that segment the constraining function along the length of the medical device. Each collar can independently restrain different sections of the device, allowing controlled sequential release rather than simultaneous spring-out, thereby maintaining positioning precision during deployment.
Solution Approach 2:
The collars are pre-positioned on the introducer assembly at specific locations along its length before the procedure. This preliminary positioning enables the clinician to plan and execute controlled sequential release of the medical device at predetermined locations, ensuring accurate placement while managing the expansion force.
2Manufacturing precision
If intermediate constraining mechanisms are added to enable sequential release, then placement control is improved, but the design complexity increases
Solution Approach 1:
The collars are designed with multi-functionality: they provide mechanical constraining of the medical device, serve as attachment points for restraining wires, and can be positioned at various locations along the introducer. This universal design allows a single collar structure to fulfill multiple functions, reducing overall system complexity despite adding intermediate constraining points.
Solution Approach 2:
Each collar is designed with local quality features including a bore for restraining wires and a tapered portion for secure engagement. These localized structural features enable the collars to provide effective constraining at specific points without requiring complex overall design, allowing sequential release capability while maintaining relatively simple individual collar structures.
3Ease of operation
If multiple collars with restraining elements are added to the carrier element, then sequential release and controlled expansion is enabled, but the manufacturing complexity increases
Solution Approach 1:
The collars are designed as thin-walled cylindrical structures with bore features, resembling flexible shell components. This design allows them to be manufactured using standard processes such as laser drilling, electrical discharge machining (EDM), or hydroforming, which are well-established in the medical device industry. The thin-walled structure reduces material usage and simplifies manufacturing despite adding multiple components.
Solution Approach 2:
The collars are designed to be nested or stacked along the elongate carrier element, with each collar fitting over the previous one. This nesting arrangement simplifies assembly during manufacturing, as the collars can be sequentially positioned and secured to the carrier element without requiring complex alignment procedures, thereby easing the manufacturing 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 solution enables precise and controlled deployment of medical devices by restraining them at multiple points along their length, reducing sudden expansion and improving placement accuracy, accommodating a variety of device shapes and dimensions with a simple and efficient design.
Implementation Method 1
the or each sleeve or collar has a length from 3 to 10 millimetres, preferably of between 4 and 6 millimetres... the or each sleeve or collar has a diameter no more than around 50% greater than the diameter of the elongate element... the or each sleeve or collar may have a height of around 1 millimetre
Data Source
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Figure 5
AI summary
An introducer assembly includes a carrier element (10) provided with an elongate cannula or catheter (12) upon which a plurality of sleeves (20) are disposed. The sleeves (20) are located within a zone (18) at which a medical device (40) is carried. The sleeves (20) include restraining mechanisms, typically channels (30), for receiving respective trigger wires (42-44). The medical device (40) is radially constrained by the trigger wires (42-44), in combination with the sleeves (20). The sleeves (20) are initially provided as separate elements which are fitted onto the elongate carrier (12) in a number and at locations suitable for the medical device (40) to be located on the carrier element (2). The arrangement provides a simple and effective restraining structure which can be adapted for different medical devices (40) and an arrangement in which the medical device (40) is radially constrained from within.