Partial Needle Retraction for Lower-Pressure Subcutaneous Injection
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Solution Overview
Problem
Subcutaneous drug delivery devices experience pressure buildup at the injection site due to limited blood vessels, leading to variability in injection time and patient discomfort.
Innovation Solution
Incorporation of a motor-driven drug delivery member with a force sensor and controller to partially retract the delivery member upon detecting a predetermined threshold force, thereby increasing the injection cavity size and reducing tissue resistive pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subcutaneous injection is used for gradual drug release, then automated injection can simplify the process for certain patient groups, but pressure buildup at the injection site causes variability in injection time and patient discomfort
Solution Approach 1:
The drug delivery member is dynamically retracted based on real-time force feedback from the force sensor. When resistive pressure exceeds a threshold, the controller activates the motor to retract the delivery member, creating additional cavity volume. This dynamic adjustment resolves the contradiction by adapting the injection system to changing tissue pressure conditions, maintaining ease of operation while reducing harmful pressure buildup.
Solution Approach 2:
A force sensor provides real-time feedback on the resistive pressure at the injection site. The controller monitors this force data and automatically adjusts the drug delivery member position accordingly. This feedback mechanism enables the system to detect and respond to pressure buildup, resolving the contradiction between automated injection convenience and tissue pressure management.
2Reliability
If the drug delivery member is fully inserted to ensure proper drug delivery, then effective drug administration is achieved, but tissue resistive pressure increases causing pain and variability
Solution Approach 1:
The drug delivery member is retracted partially rather than fully withdrawn, maintaining sufficient insertion depth for effective drug delivery while creating enough additional cavity volume to reduce resistive pressure. This partial action resolves the contradiction by providing just enough retraction to alleviate pressure without compromising drug delivery effectiveness.
Solution Approach 2:
The system changes the position parameter of the drug delivery member dynamically based on force feedback. By adjusting the insertion depth parameter in response to detected pressure conditions, the system maintains reliable drug delivery while managing injection cavity pressure to reduce patient discomfort.
3Object-affected harmful factors
If a motor-driven system with force sensor and controller is added to dynamically adjust delivery member position, then tissue resistive pressure is reduced, but device complexity increases
Solution Approach 1:
The motor serves multiple functions: it advances the drug delivery member to the injection site and also retracts it when pressure buildup occurs. The force sensor and controller work together as an integrated feedback system that automatically manages pressure without requiring separate mechanisms. This multi-functionality resolves the contradiction by reducing overall device complexity while maintaining the ability to reduce tissue resistive pressure.
Data Source
AI summary
Methods, devices, and components are provided to reduce tissue resistive pressure during a subcutaneous drug delivery operation by increasing the size of the injection cavity by partially retracting the drug delivery member after inserting the drug delivery member to a subcutaneous position. The drug delivery devices described herein include a motor operably coupled to a drug delivery member. The motor can be selectively activated by a controller to retract the drug delivery member a predetermined distance to relieve pressure in an injection cavity in a patient. A force sensor can provide the controller with a drug delivery member insertion force. The controller can then estimate a tissue resistive pressure based on the drug delivery member insertion force and determine the predetermined distance for the partial drug delivery member retraction based on the tissue resistive pressure.