Compliant Member Assembly for Medical Implant Retention
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Solution Overview
Problem
Existing injector systems for medical implants face challenges in maintaining the integrity and dimensional tolerance of drug-eluting implants during injection, storage, and transport, often resulting in excessive force damage or implant loss due to inadequate retention mechanisms, which also lead to increased pain and trauma from larger needle diameters.
Innovation Solution
An injector system featuring a compliant member assembly with at least two compliant members that form a mechanical stop and frictional engagement to retain the implant, allowing slidable ejection and alignment with the needle bore, reducing the need for stringent dimensional tolerances and minimizing injection force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retaining mechanism (such as friction ribs or spring mechanism) is used to prevent implant from falling out, then implant retention is improved, but implant damage or excessive injection force occurs
Solution Approach 1:
The patent employs a flexible membrane that can deform elastically to engage and retain the implant. The membrane's flexibility allows it to conform to the implant surface without causing damage, while still providing sufficient frictional engagement to prevent implant dislodgement during transport and storage.
Solution Approach 2:
The membrane's engagement characteristics change based on its deformation state. When deformed, it provides strong retention forces; when relaxed, it allows smooth implant ejection. This dynamic parameter change enables the same structure to provide both retention and safe delivery without damaging the implant.
2Reliability
If a large diameter needle is used to accommodate a retaining spring mechanism, then implant retention is improved, but patient pain and trauma increase
Solution Approach 1:
The retaining mechanism (flexible membrane) is extracted from the needle component and placed in the holder assembly. This separation allows the use of a small-bore needle for patient injection while the larger membrane structure remains in the holder to provide retention functionality.
Solution Approach 2:
The injector system is divided into separate functional components: the holder assembly containing the flexible membrane retention mechanism, and the needle assembly for patient injection. This segmentation allows each component to be optimized independently - the holder for retention and the needle for minimal trauma.
3Reliability
If stringent dimensional tolerances are applied to the implant, then retention reliability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The flexible membrane's ability to deform allows it to accommodate variations in implant dimensions. Instead of requiring precise dimensional control of the implant, the membrane adapts its shape and engagement force to match the actual implant geometry within a wider tolerance range.
Solution Approach 2:
The flexible membrane is made from elastomeric material that combines compliance with sufficient frictional engagement capability. This material property allows the system to retain implants with varying dimensions without requiring tight manufacturing tolerances.
4Reliability
If the compliant members form a complete occlusion of the through-passage, then implant retention is improved, but implant ejection becomes difficult
Solution Approach 1:
The flexible membrane transitions between different states: deformed to engage and retain the implant during storage and transport, and relaxed to allow smooth ejection during injection. This dynamic state change enables the membrane to provide strong retention when needed while minimizing resistance during delivery.
Solution Approach 2:
The membrane provides partial occlusion of the through-passage rather than complete blockage. This partial engagement is sufficient to prevent implant dislodgement through frictional forces while allowing the implant to pass through with acceptable injection forces when the membrane is relaxed.
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 system ensures reliable delivery and retention of the implant during injection and transport, reduces trauma and pain by allowing smaller needle diameters, and accommodates various implant sizes without significant increases in injection force, enhancing the reliability and versatility of the injector system.
Implementation Method 1
the compliant member assembly (150) is configured in the biased state as a mechanical stop adapted to stop slidable entry of the implant (200) into the bore (404) under a force of gravity
Implementation Method 2
the through-passage (154) is configured to receive slidably the implant under a force of injection in which the at least two compliant members (152) deform and frictionally engage the implant (200)
Data Source
Figure 1A~3
Figure 4~6
Figure 7A~9B
AI summary
An injector system (500) for injection by puncture of an organ, of a non-deformable medical implant (200) into a subject comprising: a holding element (100) having a proximal (10) and distal (20) end disposed with a chamber (102) for containing the implant (200), wherein the holding element (100) is disposed with an exit port (104) at the distal end (20) for slidable ejection of the implant (200) therethrough and into a bore (404) of a needle component (402) of an injection needle assembly (400), a compliant member assembly (150) having a through-passage (154), comprising at least two compliant members (152), the compliant member assembly (150) having a biased state in which the at least two compliant members (152) additively form a partial or total occlusion of the through-passage (154), wherein: the compliant member assembly (150) is configured in the biased state as a mechanical stop adapted to stop slidable entry of the implant (200) into the bore (404) under a force of gravity, the through-passage (154) is configured to receive slidably the implant under a force of injection in which the at least two compliant members (152) deform and frictionally engage the implant (200), the complaint member assembly (150) is configured to align the implant with the bore of the needle component.