Removable Vena Cava Filter with Resilient Anchoring

Solution Overview

Problem

Current vena cava filters are typically permanent and cannot be easily removed once endotheliosis occurs, leading to trauma risks during removal, and existing designs cause scratching or scraping of blood vessel walls during deployment and retrieval.

Innovation Solution

A removable filter design featuring primary struts with anchoring hooks and resistant portions that distribute pressure, reducing the depth of penetration and allowing for non-traumatic removal, along with secondary struts for centralization and a retrieval hook for easy extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If anchoring hooks are used to secure the filter in place, then the filter remains stable and prevents migration, but the hooks scrape or scratch the blood vessel wall during delivery and retrieval

Engineering Contradiction:

Improvefilter stabilityVSAvoidvessel wall trauma

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The primary strut is divided into functionally distinct segments: a resilient portion that contacts the vessel wall and an anchoring hook portion that secures the filter. This segmentation allows the resilient portion to bear the mechanical load and protect the vessel wall, while the anchoring hook provides secure fixation without causing trauma during delivery and retrieval.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resilient portion acts as a cushioning element positioned between the anchoring hook and the vessel wall. This resilient portion absorbs mechanical stresses and prevents direct contact between the rigid anchoring hook and the vessel wall, thereby protecting the vessel from scraping or scratching during filter deployment and retrieval operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the filter is designed for permanent implantation with deep anchoring hook penetration, then the filter remains securely in place, but removal becomes traumatic or impossible when endotheliosis occurs

Engineering Contradiction:

Improvefilter anchoring securityVSAvoidfilter removability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The primary strut is divided into functionally distinct segments: a resilient portion that contacts the vessel wall and an anchoring hook portion that secures the filter. This segmentation allows the resilient portion to bear the mechanical load and protect the vessel wall, while the anchoring hook provides secure fixation without causing trauma during delivery and retrieval.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resilient portion changes its mechanical parameters (compliance, contact pressure) in response to physiological conditions. When the filter is first implanted, the resilient portion is compressed against the vessel wall, providing strong anchoring. Over time, as endotheliosis occurs, the resilient portion gradually relaxes, reducing penetration depth and allowing for non-traumatic removal when needed.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the primary struts exert strong pressure on the vessel wall to prevent migration, then the filter remains stable, but the anchoring hooks penetrate deeper causing more trauma

Engineering Contradiction:

Improvefilter stabilityVSAvoidvessel wall penetration depth

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The primary strut is divided into functionally distinct segments: a resilient portion that contacts the vessel wall and an anchoring hook portion that secures the filter. This segmentation allows the resilient portion to bear the mechanical load and protect the vessel wall, while the anchoring hook provides secure fixation without causing trauma during delivery and retrieval.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resilient portion serves as an intermediary element between the primary strut and the vessel wall. It mediates the force transmission by distributing the mechanical load over a larger surface area and reducing peak contact pressures, thereby preventing deep penetration of the anchoring hook while maintaining filter stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8246648B2Removable vena cava filter with improved leg

Publication Date: 2012.08.21 COOK MEDICAL TECHNOLOGIES LLC

AI summary

A removable filter for capturing thrombi in a blood vessel. The filter has primary struts with first ends attached together along a longitudinal axis. Each primary strut has a body member extending from its first end along the longitudinal axis to an anchoring hook. Each primary strut is configured to move relative to the longitudinal axis between an expanded state and a collapsed state. At least one primary strut has a resistant portion next to the anchoring hook. The resistant portion is configured to contact the blood vessel in the expanded state. The filter also has secondary struts. The secondary struts have proximal ends attached together along the longitudinal axis and distal ends located radially from the longitudinal axis in the expanded state. The secondary struts are configured to engage the blood vessel to centralize the filter in the expanded state in the blood vessel.