Steerable Catheter Braided Reinforcement with Varying Pick Counts

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Solution Overview

Problem

Conventional steerable catheters face challenges in maintaining precise control over bending within a predetermined plane due to high forces applied by axial steering members, leading to lateral deflection and compressive loading issues, which can result in inaccurate positioning of medical devices within bodily cavities.

Innovation Solution

A steerable catheter design featuring a braided reinforcement structure with varying pick counts along different portions of the shaft, including a higher pick count in the steerable portion, embedded within a polymer matrix, to enhance flexibility and resistance to compressive loading, while maintaining a small diameter suitable for percutaneous delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If high forces are applied by axial steering members to deflect the catheter, then the catheter can be steered, but lateral deflection from the predetermined plane occurs

Engineering Contradiction:

Improvesteering capabilityVSAvoidpositional accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The catheter shaft incorporates a braided reinforcement structure with varying pick counts at different locations. The steerable portion has a higher pick count (e.g., 18-24 picks per inch) compared to non-steerable portions (e.g., 6-12 picks per inch), creating localized differences in flexibility and compressive resistance that enable controlled deflection without lateral deviation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The catheter combines a braided reinforcement structure (metallic or polymer filaments) embedded in a polymer matrix material to create a composite shaft. This composite construction provides both the flexibility needed for steering and the structural integrity to resist compressive loading and prevent lateral deflection

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If high forces are applied by axial steering members to deflect the catheter, then the catheter can be steered, but compressive loading causes the catheter to shorten

Engineering Contradiction:

Improvesteering capabilityVSAvoidcatheter length

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The braided reinforcement structure features a higher pick count in the steerable portion, creating localized increased resistance to compressive loading. This prevents shortening of the catheter shaft during steering operations while maintaining overall flexibility for deflection

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The composite construction with braided filaments embedded in polymer matrix provides superior compressive strength compared to pure polymer materials. The braided structure acts as a reinforcement cage that resists buckling and shortening under compressive loads during steering

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If the catheter is made more flexible to enable bending, then steering is improved, but resistance to compressive loading decreases

Engineering Contradiction:

Improvebending flexibilityVSAvoidcompressive loading resistance

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

Different pick counts in different portions of the catheter create localized property variations. The steerable portion has higher flexibility for bending while the reinforced portions provide compressive resistance, achieving both requirements in different locations of the same catheter

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The braided reinforcement structure embedded in polymer matrix creates a composite material that simultaneously provides flexibility for bending (through the polymer matrix) and resistance to compressive loading (through the rigid braided filaments)

Inventive Principle:

Principle #40Composite materials

4Volume of moving object

If the catheter diameter is reduced for percutaneous delivery, then minimally invasive access is enabled, but structural support for steering is reduced

Engineering Contradiction:

Improvecatheter diameterVSAvoidstructural support

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The composite construction with braided filaments provides high strength-to-weight and high strength-to-diameter ratios. This enables the catheter to maintain adequate structural support for steering while keeping the overall diameter small enough for percutaneous delivery through arterial access

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The braided reinforcement structure is strategically positioned and configured with varying pick counts to provide maximum structural support only where needed (in steerable portions), allowing diameter reduction in non-critical sections while maintaining steering capability

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20230008203A1Medical system including steerable catheter and method of manufacturing

Publication Date: 2023.01.12 KARDIUM

AI summary

A steerable catheter may include an elongate shaft member and a braided reinforcement structure embedded into a wall of the elongate shaft member. The braided reinforcement structure may include a first braided portion including a first pick count, a second braided portion including a second pick count, and a third braided portion including a third pick count. The third pick count may be greater than each of the first pick count and the second pick count.