Strain-Gauged Set Screw for Spinal Rod Force Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surgical technologies face challenges in monitoring the connection force and integrity between spinal rods and fasteners, making it difficult to ensure proper or acceptable force is maintained during and after implantation.
Innovation Solution
A spinal construct with a gauge, such as a strain gauge, is integrated into the setscrew to measure the force between the setscrew and spinal rod, with the thread forms timed and/or clocked to position the gauge in a selected orientation relative to the spinal implant, allowing for continuous monitoring of the connection force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a setscrew is used to secure the rod with the fastener, then the connection force is maintained, but the connection force and integrity cannot be monitored during and after implantation
Solution Approach 1:
A gauge element is introduced as an intermediary component within the setscrew to detect and provide information about the connection force between the setscrew and rod. This mediator enables monitoring of the connection integrity without compromising the mechanical function of the setscrew assembly.
Solution Approach 2:
The gauge element provides feedback information about the connection force state to the user or monitoring system. This feedback mechanism allows real-time or postoperative assessment of whether the connection force is maintained at acceptable levels, enabling timely intervention if necessary.
2Measurement precision
If the gauge is positioned to measure force accurately, then measurement precision is improved, but the thread form timing and clocking complexity increases
Solution Approach 1:
The thread form timing and clocking features are designed and positioned in advance during manufacturing to ensure that when the setscrew is assembled and tightened, the gauge element automatically assumes the correct orientation and position for accurate force measurement. This preliminary configuration eliminates the need for complex post-assembly alignment procedures.
Solution Approach 2:
The thread form timing features and gauge positioning elements are designed with asymmetric geometries that create a unique, predetermined orientation when engaged. This asymmetric design ensures that the gauge is positioned at the optimal angle and location for measuring the connection force, simplifying the overall alignment process while maintaining measurement precision.
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 continuous monitoring of the fusion progress and biomechanical performance of spinal implants, providing early detection of potential issues and allowing for timely intervention, thus improving surgical outcomes and implant design.
Implementation Method 1
A gauge, such as a strain gauge, is integrated into the setscrew to measure the force between the setscrew and spinal rod
Data Source
AI summary
Embodiments pertaining to a medical construct are disclosed. The medical construct may include a set screw extending along a longitudinal axis between a proximal portion and a distal portion, for example. In various embodiments, the set screw may have an outside thread form and an interior socket, for example. In various embodiments, the socket may extend parallel to the longitudinal axis and have a circular lower surface, for example. In various embodiments, a first strain gauge, a second strain gauge, a third strain gauge, a fourth strain gauge, and a fifth strain gauge may be provided. In at least some embodiments, each of the first, second, third, and fourth strain gauges may be symmetrically disposed with respect to the lower surface, for example. Additionally, in at least some embodiments, the fifth strain gauge is disposed within a center portion of the lower surface, for example.