Coiled Cannula Anchoring for Longer-Wear Insulin Infusion
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Solution Overview
Problem
Infusion sets in continuous subcutaneous insulin infusion (CSII) therapy face challenges such as foreign body reaction (FBR), leading to wear time limitations, skin irritation, and incorrect cannula placement, which can result in reduced insulin sensitivity and increased risk of hypoglycemia.
Innovation Solution
An infusion device with a cannula that forms a coil within a housing, allowing for controlled insertion and anchoring in soft tissue, utilizing superelastic materials like nitinol to enhance placement and reduce FBR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cannula is inserted directly into soft tissue, then insertion is simple, but incorrect placement occurs and FBR increases
Solution Approach 1:
The cannula is designed with a pre-formed coil configuration that transforms the straight insertion path into a controlled spiral deployment. This curvature enables the distal end to naturally anchor in the hypodermis layer while the proximal end remains accessible, achieving precise placement without complex insertion techniques
Solution Approach 2:
The cannula is pre-configured in a coil shape before insertion, with the distal end prepared to form an anchor in advance. This preliminary configuration ensures that upon insertion, the cannula automatically achieves correct positioning in the hypodermis layer, eliminating the need for complex real-time adjustment during the procedure
2Duration of action of stationary object
If the cannula remains in place for extended wear time, then continuous insulin delivery is improved, but FBR and skin irritation increase
Solution Approach 1:
The distal end of the cannula is designed as a separate anchor portion that remains embedded in the hypodermis while the proximal portion can be removed or replaced. This extraction principle allows the infusion site to heal while maintaining continuous insulin delivery through a new cannula, effectively managing FBR by separating the permanent anchor from the temporary infusion pathway
Solution Approach 2:
The cannula is functionally segmented into a distal anchor portion and a proximal infusion portion. The distal coil anchor remains in place to maintain positioning, while the proximal portion can be exchanged to allow the infusion site to recover, thereby extending overall wear time while managing foreign body reaction
3Device complexity
If syringes and pens are used for insulin delivery, then device complexity is low, but frequent needle sticks are required
Solution Approach 1:
The device combines the reservoir, pump mechanism, and cannula into an integrated infusion pump system that can continuously deliver insulin without requiring repeated needle sticks. The coil cannula design enables this merger by providing both stable anchoring and accessible connection points, allowing the system to function as a unified long-term solution rather than separate components requiring frequent replacement
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
The device improves cannula placement, reduces FBR, and extends wear time, providing stable insulin delivery over an extended period, up to 14 days, while minimizing patient discomfort and cosmetic issues.
Implementation Method 1
utilizing superelastic materials like nitinol to enhance placement and reduce FBR
Data Source
AI summary
An infusion device comprising a cannula and a housing for containing the first cannula. The cannula is movable from a retracted position within the housing to an extended position in which a distal portion of the cannula extends from the housing for insertion into soft tissue of a patient and to form an anchor therein for securing the infusion device to an infusion site.