Cannula Insertion Mechanism With Trocar Segmentation
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Solution Overview
Problem
Existing drug delivery devices face challenges with patient discomfort due to the rigidity of injection members and the complexity of insertion mechanisms, which can increase the size, cost, and discomfort of the devices.
Innovation Solution
A wearable drug delivery device with a trocar and cannula insertion mechanism that includes a manifold guide and biasing members, allowing for a sterile fluid pathway and efficient insertion and retraction of the trocar, reducing patient discomfort and device complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid injection needle is used for drug delivery, then the injection member can penetrate skin effectively, but the patient experiences discomfort and unease during extended wear
Solution Approach 1:
The injection member is segmented into two distinct parts: a rigid trocar for initial skin penetration and a flexible cannula for extended drug delivery. The trocar penetrates the skin effectively while the flexible cannula remains in the patient's body, bending to accommodate body movements and reducing discomfort. This segmentation allows each component to optimize its specific function without the drawbacks of a fully rigid structure.
Solution Approach 2:
The rigid trocar is extracted from the final drug delivery configuration. The trocar is used only for initial skin penetration and then retracted, leaving only the flexible cannula in place for drug delivery. This extraction eliminates the discomfort associated with rigid needles during extended wear while preserving the penetration capability provided by the trocar during the insertion phase.
2Object-affected harmful factors
If a flexible cannula is used for drug delivery, then patient comfort is improved, but the cannula has difficulty penetrating the patient's skin during insertion
Solution Approach 1:
The rigid trocar performs the preliminary action of skin penetration before the flexible cannula is deployed. The trocar, being rigid and sharp, easily penetrates the skin to create an initial opening. Once the skin is breached, the flexible cannula is advanced through the created opening, eliminating the need for the flexible cannula to penetrate skin on its own. This preliminary action by the trocar enables the flexible cannula to be inserted without compromising patient comfort.
3Ease of operation
If an introducer needle or trocar is used to create a passageway for the cannula, then cannula insertion is facilitated, but the device size and complexity increase
Solution Approach 1:
The trocar and cannula are merged into a single integrated insertion assembly where the cannula is disposed within the trocar. This combined structure allows the rigid trocar to provide skin penetration capability while the flexible cannula is pre-positioned for subsequent advancement. The merging eliminates the need for separate insertion devices and complex manual manipulation procedures, simplifying the overall insertion process while maintaining ease of cannula deployment.
4Stability of the object's composition
If the trocar is left inside the patient for extended periods, then the injection member remains stable, but patient discomfort and unease increase
Solution Approach 1:
The injection member is segmented so that only the flexible cannula remains in the patient's body for extended periods, while the rigid trocar is removed. The flexible cannula accommodates body movements through its flexibility, maintaining stability and fluid pathway integrity without causing the discomfort associated with leaving a rigid trocar in place. This segmentation allows the stable drug delivery function to be maintained while eliminating the harmful effect of prolonged trocar presence.
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 solution enables comfortable and efficient drug delivery with reduced patient discomfort and device complexity, while minimizing the time the trocar is in the patient's body, thus improving user experience and manufacturing efficiency.
Implementation Method 1
an insertion biasing member initially retained in an energized state between the proximal end of the insertion mechanism housing and the hub, and a retraction biasing member initially retained in an energized state between the hub and the manifold guide
Data Source
AI summary
An insertion mechanism for a wearable drug delivery device that deploys a small gauge flexible cannula with support of a coaxial rigid trocar or hollow needle. After insertion, the trocar or hollow needle is withdrawn leaving the cannula in place for drug delivery. The insertion mechanism may also include an insertion mechanism housing having a proximal and distal end, a manifold configured to fluidly connect the hollow interior of the cannula and the fluid pathway connector, and a manifold guide carrying the manifold and movable between a first position and a second position. A hub carries the trocar and is removably connected to the manifold guide. An insertion biasing member may be initially retained in an energized state between the proximal end of the insertion mechanism housing and the hub, and a retraction biasing member may be initially retained in an energized state between the hub and the manifold guide.