Invasive Medical Needle With Integrated Displacement Sensor
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Solution Overview
Problem
Existing medical needles for invasive procedures face challenges in precise positioning due to complexity, large diameter, and high cost, making them unsuitable for frequent and simple interventions like epidural injections, as they often require additional components and are not compatible with standard commercial needles.
Innovation Solution
A needle with a flexible joint and integrated displacement sensor, using either an optical fiber or miniature electric strain gauge, to detect contact forces during insertion, allowing for in vivo and in situ confirmation of correct placement without affecting the needle's dimensions or functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional components are inserted into the needle lumen to enable precise positioning, then measurement precision is improved, but device complexity increases and compatibility with standard needles is lost
Solution Approach 1:
The patent combines the sensing function directly into the needle shaft structure itself. A flexible printed circuit board is integrated into the shaft, with strain gauges embedded in the shaft wall to detect contact forces. This merging eliminates the need for separate sensing components that would need to be inserted into or attached to the needle, thereby maintaining simplicity while enabling precise positioning detection.
Solution Approach 2:
The needle shaft is designed to serve multiple functions simultaneously: it acts as both the penetrating instrument and the sensing element. The flexible printed circuit board integrated into the shaft allows the same needle structure to perform both mechanical penetration and electrical sensing, making the device universal and compatible with standard needle procedures while adding sophisticated measurement capabilities.
2Measurement precision
If fiber optic inserts are employed inside needles to detect tissue properties, then measurement precision is improved, but the needle dimensions and functionality are considerably affected
Solution Approach 1:
Instead of inserting separate fiber optic components into the needle lumen, the patent merges the sensing function into the shaft wall itself. Strain gauges are directly embedded in the flexible shaft structure, allowing the needle to maintain its original external dimensions and shape while incorporating sensing capabilities through the integrated flexible printed circuit board.
3Measurement precision
If sophisticated imaging systems are used for needle guidance, then measurement precision is improved, but cost and device complexity increase significantly
Solution Approach 1:
The needle performs self-sensing through integrated strain gauges that directly detect contact forces during insertion. This self-service capability eliminates the need for complex external imaging systems, as the needle itself provides real-time feedback about its position and contact with tissues through electrical signals generated by the strain gauges embedded in its shaft.
Solution Approach 2:
The flexible printed circuit board with strain gauges provides continuous feedback about needle contact forces and position during insertion. This real-time electrical feedback mechanism allows practitioners to sense tissue contact and adjust positioning without requiring complex external imaging systems, thereby reducing overall system complexity while maintaining measurement precision.
4Ease of manufacture
If standard commercial needles are used without modifications, then ease of manufacture is improved, but the ability to detect contact forces and confirm placement is lost
Solution Approach 1:
The patent merges the sensing function directly into the needle shaft through integration of a flexible printed circuit board and embedded strain gauges. This approach maintains the simplicity of manufacturing standard needles while adding the capability to detect contact forces, as the sensing elements are incorporated into the shaft structure itself rather than requiring separate assembly steps.
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
Enables precise and cost-effective production of disposable needles that provide real-time feedback on needle placement, ensuring accurate positioning in liquid or gaseous environments, reducing the risk of unintended tip placement and facilitating high-volume manufacturing.
Implementation Method 1
a flexible joint (11) with a notch (12) is arranged within the shaft (3) at the beginning of the shaft end (4), allowing a relative movement from the shaft end (4) relative to the rest of the shaft (3)
Implementation Method 2
The optical fiber sends out light which is reflected at its fiber end as well as at the reflective surface at the shaft end, receives this reflected light and leads it as a signal conductor to an evaluation unit
Implementation Method 3
the displacement sensor comprises a miniature electric strain gauge at the flexible joint
Data Source
AI summary
A needle for invasive medical use includes a long extended cylindrical needle shaft having an axis and an outer surface area, with a short shaft end at a first end of the shaft with a beveled tip with a pointed end, and a needle hub attached to a second end of the shaft including a device to indicate the location of the shaft end during use inside a body. The needle has a flexible joint with a notch within the shaft at the beginning of the shaft end. The device is a displacement sensor for detecting a displacement of the shaft end relative to the rest of the shaft resulted from a force applied to the shaft end when the needle hub is moved and a signal conductor to transmit the detected signals. The invention further describes a needle assembly comprising such a needle and a syringe attached to said needle hub, whereas an evaluation unit is connected to the signal conductor.