Locking Loop Catheter Filament Retraction Mechanism

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Solution Overview

Problem

Locking loop drainage catheters are cumbersome to lock and unlock, leading to suture entanglement issues and potential suture retention in the body, with fluid leaks due to exposed suture ends.

Innovation Solution

A catheter design featuring a retractable and adjustable filament with a secured distal end and retraction mechanism that creates a looped configuration by tensioning the filament, allowing easy locking and unlocking without the need for manual suture manipulation, and ensuring the filament remains attached to the catheter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the free end of the suture is pulled proximally to create the loop, then the catheter is locked in place, but the locking process becomes time-consuming and cumbersome

Engineering Contradiction:

Improvecatheter positioning stabilityVSAvoidlocking and unlocking time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The filament is pre-positioned through the tube lumen with its distal end extending outside the tube before use. The proximal end is attached to a retraction mechanism that is pre-loaded in an extended state, ready to rapidly retract the filament and create the loop without manual manipulation during the procedure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The manual mechanical manipulation of pulling and tying the suture free end is replaced by an automated retraction mechanism that uses a spring-loaded or motor-driven system to rapidly retract the filament, creating the loop and locking the catheter in place with a simple actuation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the suture extends through side ports with the free end protruding, then the loop can be created, but fluid leaks occur at the protrusion location

Engineering Contradiction:

Improveloop creation capabilityVSAvoidfluid leakage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The filament is nested within the tube lumen for most of its length, with only the necessary distal portion extending outside the tube to create the loop. The filament passes through the tube wall at controlled locations (entry and exit ports) that are sealed or designed to prevent fluid leakage while allowing filament movement.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The problematic protruding free end is extracted or eliminated by securing the filament to the tube structure. The filament is attached to the tube at the entry port or along its length, so that when retracted, it creates the loop without requiring a protruding end that could leak fluid.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If the hub is cut off after the procedure, then the catheter can be retrieved, but the suture becomes stuck to tissue and is left behind in the body

Engineering Contradiction:

Improvecatheter retrieval efficiencyVSAvoidsuture retention in body

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The filament maintains continuous attachment to the tube structure throughout its entire length, from the proximal end secured to the hub through the tube wall to the distal end. This continuous attachment ensures that when the hub is removed for catheter retrieval, the filament is pulled back through the tube or remains attached to the tube, preventing any portion from being left behind in the patient's body.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The tube structure acts as an intermediary that connects and secures the filament at multiple points. This intermediary attachment system ensures that the filament cannot become detached or left in the body during retrieval, as it is mechanically coupled to the tube which is being removed with the hub.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If the suture is secured to the tube, then the filament cannot be separated, but the complexity of the device increases

Engineering Contradiction:

Improvefilament-tube attachment securityVSAvoiddevice structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The filament is secured to the tube at specific localized points rather than along its entire length. The distal end of the filament is attached to the tube at the entry port or near the distal tip, and the proximal end is secured to the hub structure. These localized attachment points provide secure fixation without requiring complex attachment mechanisms along the entire filament length, maintaining device simplicity.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10456565B2Locking loop catheter

Publication Date: 2019.10.29 COOK MEDICAL TECHNOLOGIES LLC

AI summary

A drainage catheter system includes an elongate tube with proximal and distal ends and a filament extending the tube that is adjustable to create a closed loop at the distal end of the tube when the filament is retracted relative to the tube. The filament is coupled to the tube such that the filament and tube are prevented from being separated in the event that the tube and filament are cut at the proximal end at the conclusion of a drainage procedure. The filament can be attached to the tube near the distal end. The filament can be attached to the tube along its length. The catheter system can also include a retraction mechanism having a first fixed position and second fixed position, where the second fixed position retracts the filament proximally relative to the first fixed position by actuating a plunger.