Spinal Setscrew Gauge for Connection Force Monitoring
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Solution Overview
Problem
Current spinal constructs face challenges in monitoring the connection force between vertebral rods and bone fasteners, particularly setscrews, during and after implantation, as it is difficult to ensure proper or acceptable force is maintained, affecting the stability and integrity of the spinal implantation.
Innovation Solution
A spinal construct with a gauge integrated into the setscrew, which measures the force between the setscrew and spinal rod, utilizing a timed and/or clocked thread form to position the gauge in a selected orientation relative to the spinal implant, allowing for accurate force measurement and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gauge is integrated into the setscrew to measure connection force, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The gauge is integrated directly into the setscrew component, merging the measurement function with the fastening component. This allows force measurement capability to be added without requiring a separate, independent measurement device, thereby improving measurement precision while limiting the increase in overall device complexity.
Solution Approach 2:
The setscrew serves multiple functions: it provides mechanical fastening through its thread form engagement with the bone screw, and simultaneously serves as a force measurement device through the integrated gauge. This multi-functionality allows a single component to address both structural support and monitoring requirements.
2Measurement precision
If the gauge is positioned using timed and/or clocked thread form, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The thread forms of the bone screw and setscrew are designed with predetermined timing or clocking features during the manufacturing stage. This preliminary action ensures that when the setscrew is engaged with the bone screw, the gauge automatically assumes the correct orientation relative to the spinal implant, eliminating the need for complex post-manufacturing alignment procedures.
Solution Approach 2:
The thread form design incorporates specific geometric parameters and angular relationships that, when engaged, automatically position the gauge at the desired orientation. By encoding the orientation information into the thread form geometry itself, the system transforms a complex alignment problem into a straightforward engagement process.
3Reliability
If continuous monitoring of fusion progress is enabled, then reliability is improved, but device complexity increases
Solution Approach 1:
The spinal construct performs self-monitoring through the integrated gauge that continuously measures the connection force between the setscrew and spinal rod. The system uses its own operational parameters (force measurements) to assess fusion progress and detect potential issues, eliminating the need for external monitoring equipment or additional surgical interventions.
Solution Approach 2:
The gauge provides continuous feedback on the mechanical connection status, allowing the surgical team to monitor fusion progress in real-time. This feedback mechanism enables early detection of potential complications such as delayed union or connection failure, allowing for timely intervention before serious problems develop.
Data Source
AI summary
A spinal construct includes a first member having a first thread form and an implant cavity configured for disposal of the spinal implant. A second member is engageable with a spinal implant and includes a second thread form configured for engagement with the first thread form. A gauge is coupled to the second member. The gauge is configured to measure a force between the second member and the spinal implant when the second member is engaged with the first member. The second thread form is timed with the first thread form to position the gauge in a selected orientation relative to the spinal implant. Systems and methods are disclosed.