Fistula Cannula Retractable Needle Guide

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Solution Overview

Problem

Conventional vascular access devices require two-handed operation or clinician assistance for deployment and retraction, and are not self-contained, leading to patient discomfort and increased procedural complexity, especially during hemodialysis.

Innovation Solution

A self-contained vascular access device with a retractable needle assembly and needle guide that allows single-handed operation, enabling the patient to access vasculature without clinician assistance, with the needle retracting into a housing to prevent needle sticks and maintain cannula integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional vascular access devices are used, then clinician assistance is required for deployment and retraction, but this increases procedural complexity and patient discomfort

Engineering Contradiction:
Improvesingle-handed operation capabilityVSAvoiddevice structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The needle assembly, needle guide, cap, and cannula are merged into a single integrated vascular access device. The needle is mechanically coupled to the cannula via the needle guide, and the cap integrates the locking mechanism and needle retraction functionality. This merging eliminates the need for separate deployment and retraction tools, enabling single-handed operation while maintaining controlled functionality through integrated mechanical interactions between components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The device enables self-cannulation by incorporating all necessary functional elements directly into the device structure. The rotatable cap serves as a self-contained locking and retraction mechanism that the patient can operate independently. The needle guide automatically maintains proper needle alignment during retraction without requiring external guidance tools, allowing the device to service itself during the cannulation procedure.

Inventive Principle:
Principle #25Self-service

2Object-affected harmful factors

If the needle remains extended from the cannula, then insertion is facilitated, but needle sticks and patient discomfort occur during the procedure

Engineering Contradiction:
Improveneedle stick preventionVSAvoidneedle retraction control
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The needle transitions from a static extended position to a dynamic retracted position through rotation of the cap. The needle guide enables controlled movement of the needle relative to the cannula, allowing it to be extended for insertion and then retracted into the cannula or housing to prevent needle sticks. This dynamic positioning maintains safety while preserving operational capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The needle guide acts as an intermediary mechanism between the needle and the cap. It translates the rotational motion of the cap into controlled linear retraction of the needle, mediating the interaction between the user input and the needle position. This intermediary ensures safe, controlled needle retraction while preventing direct manual manipulation of the needle itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the device requires two-handed operation, then precise control is maintained, but patient independence is reduced

Engineering Contradiction:
Improveself-cannulation capabilityVSAvoidprocedural accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The cap serves multiple functions: it locks the needle in the extended position for insertion, enables controlled retraction through rotation, and can be gripped with a single hand due to its ergonomically designed outer surface. The needle guide simultaneously provides structural support, maintains needle alignment, and translates rotational motion to linear retraction. This multi-functionality enables self-cannulation while maintaining procedural accuracy through integrated mechanical design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3563897B1Fistula cannula
Publication Date: 2022.01.19 COVIDIEN LP
  • EP3563897B1 patent drawingFigure 1
  • EP3563897B1 patent drawingFigure 2A~3B
  • EP3563897B1 patent drawingFigure 4A~4B

AI summary

A device to be used to access vasculature or another hollow anatomical structure of a patient, includes a housing (12), a cannula (14) mechanically coupled to a housing distal end, and a needle assembly (16) including a needle (32) which is configured to be locked in a deployed configuration in which the needle extends within a cannula lumen and protrudes from the cannula distal end. The needle is configured to slide proximally through the cannula lumen from the deployed configuration into a retracted configuration in which at least a portion of the needle is within a housing lumen. The needle assembly further includes at least one needle guide (34) configured to maintain the needle along a path in the housing lumen substantially parallel to the needle guide when the needle moves between the deployed configuration and the retracted configuration.