Stent Mandrel Grooves for Repeatable Anti-Migration Loops

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Solution Overview

Problem

Existing stents face challenges in accurately and repeatedly forming anti-migration features, which are crucial for anchoring them in place within body lumens.

Innovation Solution

A stent design featuring interwoven first and second filaments with circumferential offsets forming anti-migration loops, and a mandrel with protrusions and grooves to facilitate the formation of these loops, ensuring secure placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional stent formation methods are used, then manufacturing simplicity is maintained, but anti-migration features cannot be formed accurately and repeatedly

Engineering Contradiction:

Improveanti-migration feature formation accuracyVSAvoidmandrel structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mandrel is pre-configured with protrusions and grooves before stent formation. These protrusions create channels that guide filament winding paths, and the grooves pre-positioned on protrusions create the circumferential offsets needed for anti-migration loops, eliminating the need for complex post-processing or complex mandrel mechanisms

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mandrel acts as an intermediary tool that translates simple protrusion-groove geometry into complex anti-migration loop structures. The protrusions serve as mediators that redirect filaments to create circumferential offsets, while the grooves mediate the formation of loops by providing localized guidance paths

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If circumferential offsets are added to helical paths, then anti-migration capability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvestent anchoring stabilityVSAvoidanti-migration loop formation difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The filament winding process automatically creates circumferential offsets and anti-migration loops through the interaction between the rotating mandrel and the fixed groove positions. The system self-organizes the complex loop structures without requiring additional actuators, controls, or manual interventions during manufacturing

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The mandrel protrusions and grooves utilize curved, circumferential geometries that naturally guide filaments into helical paths with circumferential offsets. The curved groove paths transform linear filament feeding into complex three-dimensional loop structures through geometric constraint rather than mechanical manipulation

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS12433774B2Stent, mandrel, and method for forming a stent with anti-migration features

Publication Date: 2025.10.07 BOSTON SCIENTIFIC SCIMED INC

AI summary

A medical stent having a first end, a second end, and a central longitudinal axis extending from the first end to the second end, may include a plurality of first filaments each extending in a first helical path around the central longitudinal axis in a first direction and a plurality of second filaments each extending in a second helical path around the central longitudinal axis in a second direction. The plurality of first filaments may be interwoven with the plurality of second filaments. The first helical path of at least one of the plurality of first filaments may include a circumferential offset disposed between the first end and the second end.