Set Screw Antenna Layout for Wireless Spinal Load Monitoring
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Solution Overview
Problem
Monitoring the connection force and integrity between longitudinal members and pedicle screws or other connectors in spinal implants is challenging, making it difficult to ensure proper force is maintained during and after implantation.
Innovation Solution
A load sensing assembly is introduced, featuring a set screw with a central opening containing an integrated circuit, antenna, and strain gauge, which measures the force between the set screw and longitudinal member, and can store and transmit measurements to a reader, using RFID or NFC technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional spinal implant components are used without integrated sensing capabilities, then the device structure remains simple and manufacturing is easier, but the ability to monitor connection force and integrity is insufficient
Solution Approach 1:
The patent combines multiple functional components (strain gauge, integrated circuit, antenna) into a single integrated sensing assembly that is embedded within the set screw. This merging approach enables comprehensive monitoring capabilities while minimizing the overall device footprint and avoiding the need for separate external monitoring systems.
Solution Approach 2:
The sensing assembly is nested within the set screw structure itself. The strain gauge, integrated circuit, and antenna are all contained within the central opening of the set screw, creating a compact hierarchical arrangement that adds functionality without significantly increasing external dimensions.
2Reliability
If sensing components are integrated into the set screw, then real-time monitoring capability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The strain gauge is bonded to the set screw surface during the manufacturing process before final assembly. The integrated circuit and antenna are pre-assembled within the central opening of the set screw, allowing for quality control and testing to be performed on individual components before integration into the final implant assembly.
3Volume of moving object
If the antenna is positioned within the central opening of the set screw, then the sensing assembly is more compact, but the RFID/NFC signal transmission may be affected
Solution Approach 1:
The antenna is configured to extend along the longitudinal axis of the set screw, utilizing the available length of the central opening. This dimensional arrangement allows the antenna to achieve sufficient length for effective RFID/NFC communication while remaining contained within the confined space of the set screw's central opening.
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 allows for real-time monitoring of the force between implant components, ensuring proper placement and maintaining the necessary force, thereby enhancing the stability and effectiveness of spinal implant procedures.
Implementation Method 1
a strain gauge in connection with the integrated circuit. The strain gauge is located within the central opening of the set screw in proximity to the second end of the set screw
Implementation Method 2
The integrated circuit may include one or more of the following radio frequency identification (RFID) chip, or a near-field communication (NFC) chip
Data Source
AI summary
A load sensing assembly for a spinal implant includes a set screw having a central opening that extends from a first end of the set screw toward a second end of the set screw. The second end of the set screw is configured to engage with an anchoring member. The load sensing assembly includes an antenna, an integrated circuit in communication with the antenna, where the integrated circuit is positioned within the central opening of the set screw, and a strain gauge in connection with the integrated circuit. The strain gauge is located within the central opening of the set screw in proximity to the second end of the set screw.