Flexible Intraosseous Cannula with Rigid Stylet for Bone Marrow Access

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Solution Overview

Problem

Establishing intravenous access in patients with limited or no accessible veins is challenging, especially in emergency situations, due to anatomical constraints, motion, and the risk of conventional rigid cannula dislodgment during patient movement.

Innovation Solution

A penetrator assembly comprising a flexible outer cannula with slits and a rigid inner stylet, designed to penetrate bone and associated bone marrow, which allows for secure insertion and minimizes dislodgment through a hub and connector system, with a depth control collar and distal cutting sleeve for precise placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid cannula is inserted into the bone, then the cannula can be easily inserted and maintained during the procedure, but the cannula may become dislodged when the patient moves

Engineering Contradiction:

Improvecannula rigidityVSAvoidcannula retention

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The cannula is divided into two distinct segments: a rigid proximal portion for insertion and maintenance, and a flexible distal portion for adaptation to patient movement. This segmentation allows each segment to fulfill its specific function optimally while working together as a unified system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cannula transitions from a static rigid structure to a dynamic hybrid structure where the distal portion can flex and adapt. This dynamic characteristic allows the cannula to maintain its position within the bone marrow cavity even when the patient moves, as the flexible portion absorbs the movement stresses.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a flexible cannula is used, then the cannula can adapt to patient movement, but the cannula may bend during insertion procedure

Engineering Contradiction:

Improvecannula retentionVSAvoidinsertion stability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stylet is nested within the flexible distal portion of the cannula during the insertion procedure. This nested configuration provides internal support to the flexible portion, preventing it from bending or deforming during insertion. Once insertion is complete, the stylet is removed, allowing the flexible portion to adapt to patient movement.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If the bone is too thick at the target site, then conventional needles cannot penetrate, but the penetrator assembly may require excessive force

Engineering Contradiction:

Improvebone thickness accommodationVSAvoidinsertion force

Core Design Contradiction:

Adaptability or versatilityVSForce

Solution Approach 1:

The penetrator assembly transitions from a static rigid structure to a dynamic hybrid structure where the distal portion can flex and adapt. This dynamic characteristic allows the cannula to maintain its position within the bone marrow cavity even when the patient moves, as the flexible portion absorbs the movement stresses.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The penetrator assembly combines materials with different mechanical properties: a rigid material for the proximal portion providing structural strength, and a flexible material for the distal portion providing adaptability. This composite construction allows the assembly to penetrate thick bone without requiring excessive force while maintaining reliability during patient movement.

Inventive Principle:

Principle #40Composite materials

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

Facilitates reliable and stable access to the vascular system by allowing the flexible cannula to bend with patient movement, reducing dislodgment risks and ensuring consistent access for drug administration and fluid delivery.

Implementation Method 1

the flexible outer penetrator configured to bend after removal of the rigid inner penetrator from the longitudinal bore

Methodology Applied

Scientific EffectFlexibility: Elasticity

Data Source

PatentUS20210121201A1Intraosseous access device and method to access bone marrow

Publication Date: 2021.04.29 TELEFLEX LIFE SCIENCES II LLC

AI summary

Penetrator assemblies operable to provide access to an intraosseous space are disclosed. The penetrator assembly may include a flexible outer penetrator having a longitudinal bore and a distal end operable to penetrate bone and associated bone marrow. The penetrator assembly may also include a rigid inner penetrator including a distal end operable to penetrate bone and associated bone marrow. A hub having a distal end is connected to a proximal end of the flexible outer penetrator. A connector having a distal end is connected to a proximal end of the rigid inner penetrator. A proximal end of the connector can releasably engage a driver. The longitudinal bore of the flexible outer penetrator can removably receive the rigid inner penetrator to prevent or minimize the flexible outer penetrator from bending during an insertion procedure. The flexible outer penetrator can bend after removal of the rigid inner penetrator from the longitudinal bore.