Removable Mandrin Electrode Pattern for Bioimpedance Needle Localization
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Solution Overview
Problem
Existing needle localization systems based on bioimpedance measurements are limited by the interrelationship between the needle and mandrin, making it difficult to focus on smaller areas and increasing the risk of incorrect tissue targeting, which can lead to severe complications.
Innovation Solution
A hollow needle with a removable mandrin featuring a distal end with a closed design and an electrode pattern, including at least two electrodes, allows for precise monitoring of the needle's advancement through bioimpedance measurements without external wires, improving contact with the tissue and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mandrin with electrodes is accommodated in the needle, then bioimpedance measurements can be performed to monitor needle advancement, but the interrelationship between needle and mandrin geometry limits the ability to focus measurements on smaller areas
Solution Approach 1:
The mandrin is segmented into distinct functional zones: a distal closed end with electrodes for measurement, a shaft portion for structural support, and connection elements for wiring. This segmentation allows the electrodes to be positioned precisely at the distal end while keeping the overall device manageable in size and complexity.
Solution Approach 2:
The electrode arrangement transitions from a two-dimensional surface pattern to a three-dimensional configuration by wrapping electrodes around the distal end of the mandrin. This dimensional change enables focused measurement on smaller tissue areas while maintaining electrical connectivity and reducing geometric constraints.
2Measurement precision
If wires leading to measuring devices are present, then bioimpedance measurements can be conducted, but the wires disturb the useability when the mandrin is removed from the needle channel
Solution Approach 1:
The measuring function is extracted from the needle assembly by using a removable mandrin that contains the electrodes. When the needle is removed from the tissue, the mandrin with electrodes can be detached, leaving no wires or measurement components in the patient's body, thus eliminating interference with subsequent procedures.
Solution Approach 2:
The mandrin acts as an intermediary carrier that temporarily holds the electrodes during the measurement phase. It facilitates the measurement function while being easily removable, serving as a mediator between the measurement requirement and the ease of operation requirement.
3Ease of operation
If the electrode pattern is placed on the distal end of the mandrin, then all electrodes can be disposed of after positioning to prevent interference, but the contact between electrodes and tissue must be improved for accurate measurement
Solution Approach 1:
The distal end of the mandrin is given special local quality with a closed design that concentrates all electrodes at this specific location. This localized electrode arrangement ensures optimal tissue contact at the measurement site while allowing the rest of the mandrin to be simple and easily removable.
Solution Approach 2:
The electrodes are pre-positioned on the distal end of the mandrin before needle insertion, ensuring optimal contact with the tissue at the target location. This preliminary positioning of electrodes facilitates accurate measurement without requiring complex adjustments during the procedure.
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
This solution enables more accurate needle placement, reduces the risk of complications by minimizing tissue damage and avoiding measurement interferences, and allows for flexible catheter use in conveying or removing substances from the organism.
Implementation Method 1
monitor the advancement of the distal end only on the basis of a measurement signal of bioimpedance received from the electrodes of the electrode pattern
Data Source
Figure 1A~1C
Figure 2A~3B
Figure 4A~6
AI summary
Arrangement for defining a location within an organism, said arrangement comprising: a hollow needle (2), comprising a longitudinal channel (5) and a distal end (4); a mandrin (1), accommodated in the longitudinal channel (5) in mobile manner in relation to it and removable from said channel (5) and having a distal and (3) of closed design, comprising an electrode pattern including at least two electrodes (7a, 7b, 7c, 7d); as well as a processing unit, configured to monitor the advancement of the distal end (4) only on the basis of a measurement signal of bioimpedance received from the electrodes (7a, 7b, 7c, 7d) of the electrode pattern. The application includes also an independent claim for a method for manufacturing a mandrin to be accommodated in a needle.