Intra-Articular Needle Pressure Sensing for Effused Joint Placement
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Solution Overview
Problem
Existing devices for confirming intra-articular needle placement, such as those relying on sub-atmospheric pressure detection, fail to accurately identify synovial cavities in osteoarthritis patients with effusions and positively pressured joints, leading to inefficacious injections and potential pain due to undiagnosed effusions.
Innovation Solution
A device that detects both sub-atmospheric and supra-atmospheric pressure differentials during needle insertion, using a microprocessor to analyze pressure changes and trigger visual indicators for correct synovial cavity penetration, with integrated LEDs for confirmation and optional real-time data display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a device relies solely on sub-atmospheric pressure detection to confirm needle placement, then the device complexity is reduced and manufacturing is simplified, but the measurement precision and reliability of needle placement detection deteriorates in effused joints with supra-atmospheric pressure
Solution Approach 1:
The device dynamically adapts its detection algorithm based on real-time pressure data. Instead of relying on a fixed sub-atmospheric pressure threshold, the system continuously monitors pressure changes and adjusts its detection criteria to account for varying joint conditions, including effused joints with supra-atmospheric pressure. This dynamic approach allows the device to maintain high measurement precision across diverse clinical scenarios without increasing physical device complexity.
Solution Approach 2:
The device changes the detection parameters from fixed threshold-based detection to variable parameter detection that considers pressure change rates, sustained pressure levels, and contextual clinical information. By monitoring whether pressure remains supra-atmospheric for a sustained period and analyzing the rate of pressure change, the system can reliably detect synovial cavity penetration even in effused joints, thereby improving measurement precision without complicating the device structure.
2Measurement precision
If ultrasound or fluoroscopy guidance is used to confirm needle placement, then the measurement precision and reliability improve, but the cost of equipment and staff training increases significantly
Solution Approach 1:
The device replaces complex imaging systems (ultrasound or fluoroscopy) with a simple pressure sensing mechanism. By substituting mechanical/imaging-based detection with pressure-based detection, the device achieves comparable needle placement confirmation accuracy at a fraction of the cost. The pressure sensor, microprocessor, and visual indicator components are significantly less expensive and require minimal training compared to operating ultrasound or fluoroscopy equipment.
Solution Approach 2:
The device employs inexpensive, disposable pressure-sensing components that can be discarded after single use, eliminating the need for expensive, reusable imaging equipment. This approach reduces manufacturing costs and eliminates the need for expensive maintenance and sterilization protocols associated with reusable medical imaging devices, while still providing reliable needle placement detection.
3Ease of operation
If a simple pressure threshold algorithm is used, then the ease of operation improves and minimal instruction is needed, but the reliability deteriorates when joints have supra-atmospheric pressure due to effusions or load-bearing
Solution Approach 1:
The device incorporates feedback mechanisms that monitor pressure changes over time and provide visual confirmation only when specific criteria are met. The system feedbacks information about sustained pressure levels and pressure change rates to the user through visual indicators, allowing operators to reliably distinguish true synovial cavity penetration from transient pressure changes. This feedback approach maintains ease of operation while significantly improving reliability in effused joints.
Solution Approach 2:
The device performs preliminary analysis of pressure data before triggering the penetration confirmation indicator. By pre-establishing detection criteria that consider sustained pressure duration, pressure change rates, and contextual patterns, the system prepares the detection algorithm in advance to handle supra-atmospheric pressure scenarios. This preliminary action ensures that the simple visual indicator remains easy to interpret while reliably distinguishing true penetration from false positives in effused joints.
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
Enhances the accuracy of needle placement by identifying both negative and positive pressures, reducing the risk of misplacement and enabling timely intervention for effusions, while being cost-effective and compatible with current medical practices.
Implementation Method 1
The device exploits discernable differences in pressure between extra-articular tissues and synovial cavities
Data Source
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AI summary
The present invention relates to a device for measuring, recording, and acting in response to changes in air pressures encountered through the lumen of a connected needle. The device signals when it has been powered and signals when the device recognizes both pressures and pressure change rates indicative of intra-articular or synovial cavity joint penetration, such as knee joint penetration. Synovial cavity pressures detected and acted upon may either be supra- (positive) or sub-atmospheric (negative). Internal light emitting diodes and a laptop connected display are demonstrated as signaling and communication mechanisms. Methods for delivering medicaments into human and animal intra-articular cavities or joints such as synovial cavities are provided. Furthermore, methods for facilitating the diagnoses of joint effusion also are provided.