Cannula Depth-Limiting Nodule for Injection Precision

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Solution Overview

Problem

Accurate placement and depth control of delivery cannulas are critical for effective medication administration, as improper penetration can lead to incorrect delivery routes, such as intramuscular or subcutaneous injection instead of the intended route, causing inefficacy or harm.

Innovation Solution

A cannula with depth-limiting nodules along its outer surface, which are spaced from the distal end to control insertion depth, allowing precise targeting and preventing excessive penetration through membranes like the tympanic membrane while allowing passage through intended tissues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the cannula is inserted deeper to ensure adequate penetration, then the medication delivery accuracy is improved, but the risk of intramuscular delivery instead of subcutaneous delivery increases

Engineering Contradiction:

Improvecannula insertion depth precisionVSAvoidincorrect delivery route (intramuscular instead of subcutaneous)

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-positioning depth-limiting nodules on the cannula at predetermined distances from the distal end. These nodules are positioned in advance to contact the target tissue surface at the correct depth, preventing over-penetration before it can occur. The nodules are spaced at specific distances (e.g., 0.5-2.0 inches from the tip) to ensure the cannula stops at the intended subcutaneous depth rather than penetrating into muscle tissue.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The depth-limiting nodules serve as intermediary elements between the cannula tip and the target tissue. These nodules act as mediators that translate the insertion motion into a controlled stopping point. When the nodule contacts the tissue surface, it intermediates the force transmission, preventing the cannula from penetrating deeper than the predetermined depth while still allowing adequate penetration for subcutaneous delivery.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the cannula tip is made sharper to facilitate insertion, then the ease of insertion is improved, but the control over insertion depth becomes more difficult

Engineering Contradiction:

Improveease of cannula insertionVSAvoidinsertion depth control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the cannula into functional segments: a sharp distal tip for easy insertion, a shaft portion, and proximal nodules for depth control. The sharp tip (segment 1) facilitates penetration of the skin and subcutaneous tissue, while the nodules (segment 3) positioned along the shaft provide depth limiting. This segmentation allows each portion to optimize its specific function without compromising the others.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cannula design implements self-service by incorporating self-limiting nodules that automatically stop insertion at the predetermined depth without requiring external control mechanisms. The nodules are positioned at specific distances from the tip and naturally contact the tissue surface at the correct depth, providing automatic depth control through the device's own structure rather than requiring operator judgment or external devices.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the pump is placed remotely from the cannula to provide flexibility in positioning, then the adaptability is improved, but the complexity of the delivery system increases

Engineering Contradiction:

Improveflexibility in pump and cannula positioningVSAvoidcomplexity of fluid coupling system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies flexible shells and thin films by using flexible tubing to couple the remotely positioned pump to the cannula. This flexible connection allows the pump to be placed in various locations (on the patient's body, on a table, or in a bag) while maintaining fluid delivery capability. The flexible tubing accommodates different positioning configurations without compromising the structural integrity or fluid flow of the delivery system.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS9987421B2Injectable drug delivery arrangement with controlled delivery cannula position relative to point of delivery

Publication Date: 2018.06.05 UNL HOLDINGS LLC

AI summary

A cannula for administration of a medicine to a target location includes a tube with at least one nodule disposed along the circumferential surface and spaced at a defined distance from the distal end of the tube. An arrangement for delivery of a medicine to a target location includes the cannula and a pump fluidly coupled to the cannula. The distal end of the cannula may be inserted into a target location until the nodule reaches a surface that limits a depth of penetration before delivery of the medication.