Narrow Gauge Cannula Expandable Element Design

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Solution Overview

Problem

Current bone dilatation procedures using expandable elements face challenges with narrow gauge cannulas, including difficulty in inserting and withdrawing the expandable elements due to high pressure requirements and the need for thin walls to fit through small diameters, which compromises structural integrity and leads to incomplete expansion and potential damage to bone structures.

Innovation Solution

A catheter/expandable element assembly with a double wall thickness of 0.254 mm or greater, designed to be stretched, folded, and wrapped to fit through an 11-gauge cannula, featuring a butt-jointed juncture and a single lumen catheter shaft to reduce size and facilitate passage, along with radiopaque markings at the distal tip to ensure accurate positioning without contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the expandable element uses thin walls to fit through narrow gauge cannula, then the ease of operation improves, but the structural integrity deteriorates

Engineering Contradiction:
Improveease of insertion and withdrawalVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The expandable element utilizes a thin-walled flexible membrane structure that can be compressed to a small profile for passage through the narrow gauge cannula, then expanded in situ to provide structural support. The flexibility of the thin film allows it to conform to the cannula dimensions during insertion while maintaining sufficient integrity when expanded.

Inventive Principle:
Principle #30Flexible shells and thin films

2Volume of stationary object

If high pressure is applied to expand the element completely, then the volume of the expanded cavity improves, but the reliability deteriorates due to potential damage to bone structures

Engineering Contradiction:
Improvecavity volumeVSAvoidrisk of bone damage
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The expansion process employs staged or controlled pressure application rather than single high-pressure injection. The system allows for incremental expansion with pressure monitoring and control, enabling the cavity to be formed and enlarged in controlled steps that protect surrounding bone structures while achieving the required cavity volume.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system incorporates pressure sensing and control mechanisms that provide feedback during the expansion process. This allows real-time monitoring of expansion pressure and adjustment to prevent excessive pressure that could damage bone structures, while ensuring complete cavity formation when appropriate pressure levels are reached.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the use of an 11-gauge cannula for both insertion and removal of the expandable element, ensuring complete expansion and stabilization of bone structures without lubricants, reducing the risk of contamination and improving adhesion of cement to the bone.

Implementation Method 1

the inflatable element is inflated to form, enlarge or support the interior bone region

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 2

radiopaque markings at the distal tip to ensure accurate positioning

Methodology Applied
Scientific EffectX-ray interaction: X-Ray

Data Source

PatentEP2688631B1Apparatus and methods for accessing and dilating bone structures using a narrow gauge cannula
Publication Date: 2021.12.01 NORDSON CORP
  • EP2688631B1 patent drawingFigure 1A
  • EP2688631B1 patent drawingFigure 1B
  • EP2688631B1 patent drawingFigure 1C

AI summary

Systems, apparatus and methods are disclosed for medical treatment comprising bone access and dilatation and/or cavity creation or enlargement using a narrow gauge, preferably 11-gauge or smaller, cannula wherein a catheter/expandable element assembly meeting medical protocols is designed, adapted and fabricated to fit through the interior of the associated 11-gauge or smaller cannula.