Removable Vena Cava Filter With Inward Anchoring Hooks
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Solution Overview
Problem
Conventional vena cava filters are often permanent due to endotheliosis and tilting, making them difficult to remove, and they can scratch or scrape against introducer tubes during delivery and retrieval, leading to trauma and ineffective deployment.
Innovation Solution
A removable vena cava filter with inwardly positioned anchoring hooks in a collapsed configuration, featuring primary and secondary struts that form a netting pattern to centralize the filter and prevent tilting, and a retrieval hook for simplified delivery and removal, minimizing the risk of scratching or tearing during deployment and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filters are deployed with anchoring hooks extending outward, then the filter can effectively anchor to the vessel wall, but the hooks scratch or scrape against introducer tubes during delivery and retrieval, causing trauma and making removal difficult
Solution Approach 1:
The anchoring hooks are inverted in orientation so that they face inward toward the filter center rather than outward toward the vessel wall in the collapsed configuration. This inversion allows the hooks to be pulled inward during delivery without contacting the introducer tube, eliminating scratching trauma while maintaining anchoring capability when deployed
Solution Approach 2:
The filter structure transitions dynamically between collapsed and expanded configurations. In the collapsed state, hooks are positioned inward for safe delivery; upon deployment, the filter expands and hooks engage the vessel wall for anchoring. This dynamic reconfiguration resolves the contradiction between safe delivery and effective anchoring
2Reliability
If filters remain implanted permanently, then endotheliosis and fibrous reaction matter accumulate around the filter struts, but this makes the filter difficult or impossible to remove after the medical condition has passed
Solution Approach 1:
The filter design incorporates self-retaining features through the inwardly positioned anchoring hooks that engage the vessel wall in a controlled manner. The hooks are designed to maintain anchoring through blood flow forces while allowing controlled disengagement during retrieval, enabling the filter to serve itself in maintaining position without permanent implantation
Solution Approach 2:
The filter utilizes changes in structural parameters between deployed and collapsed states. When deployed, the hooks are positioned to engage the vessel wall for stability; when collapsed for retrieval, the hooks reposition inward to disengage from the vessel wall, allowing removal after the medical condition has resolved
3Adaptability or versatility
If the filter is designed to be removable, then the underlying medical condition can be treated temporarily, but the filter may tilt or become off-centered during deployment, leading to endothelialization along the filter wire
Solution Approach 1:
The filter structure employs asymmetric design elements in the strut configuration and hook positioning that promote stable, centered deployment. The inwardly positioned hooks create an asymmetric force distribution during expansion that helps maintain the filter in a centered position, preventing tilting and off-centering that would cause endothelialization
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 filter effectively captures thrombi while being easily removable and deployable, reducing the risk of endothelialization and trauma, and can be delivered and retrieved without scratching or scraping, maintaining filter effectiveness and patient safety.
Implementation Method 1
a removable vena cava filter configured for simplified delivery to and retrieval from the vena cava of a patient... The filter is shaped for easy delivery and retrieval... The filter includes primary struts having anchoring hooks
Implementation Method 2
primary struts having anchoring hooks which are configured to be positioned inwardly away from the walls of the blood vessel when in a collapsed state
Data Source
AI summary
The present invention involves a removable filter for capturing thrombi in a blood vessel. The filter comprises a plurality of primary struts and a plurality of secondary struts. The plurality of primary struts has first ends attached together along a longitudinal axis. Each primary strut has an arcuate segment extending from the first end to an anchoring hook. The primary struts are configured to move between an expanded state for engaging the anchoring hooks with the blood vessel and a collapsed state for filter retrieval or delivery. Each primary strut is configured to cross another primary strut along the longitudinal axis in the collapsed state such that each anchoring hook faces the longitudinal axis away from the blood vessel for filter retrieval or delivery. The plurality of secondary struts has connected ends attached together along the longitudinal axis. The secondary struts extend therefrom to free ends to centralize the filter in the expanded in the blood vessel.