Bottom-Loading Pedicle Screw Assembly with Annular Clip
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Solution Overview
Problem
Current bottom-loaded pedicle screw systems lack a secure and flexible mechanism for coupling pedicle screws to spinal stabilization rods, which can lead to instability and movement issues during spinal fixation procedures.
Innovation Solution
A spine screw assembly featuring a fastener with a groove for an annular clip that transitions between increased and decreased sizes, a coupling element with a rod receiving channel, and a compression nut that translates force to the fastener head to prevent relative movement between the fixation element and coupling element, ensuring secure attachment to the stabilization rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bottom-loaded pedicle screw system is used, then flexibility and adjustment capability are improved, but secure coupling and stability are worsened
Solution Approach 1:
The clip is nested within the groove of the pedicle screw head, forming a compact integrated structure. The rod is nested within the coupling element, creating a hierarchical arrangement that provides both flexibility and secure coupling. This nesting principle allows the system to achieve adaptability while maintaining structural integrity and stability.
Solution Approach 2:
The coupling element incorporates dynamic adjustment capabilities that allow it to adapt to different rod positions and orientations while maintaining secure coupling. The mechanism enables real-time adjustments during spinal fixation procedures, providing both flexibility and reliable stability through controllable dynamic behavior.
2Strength
If a compression nut is used to clamp the rod and pedicle screw head together, then connection strength is improved, but device complexity is worsened
Solution Approach 1:
The compression nut is merged with the coupling element to form an integrated assembly. This combination reduces the number of separate components and simplifies the overall device structure while maintaining the clamping function that provides strong connection between the rod and pedicle screw head.
Solution Approach 2:
The coupling element is designed to perform multiple functions: it provides structural support, enables rod attachment, facilitates compression through the integrated nut, and allows for positional adjustment. This multi-functionality reduces the need for additional specialized components, thereby reducing device complexity while maintaining connection strength.
Data Source
AI summary
A spine screw assembly is adapted to be loaded from a bottom of a receiver member. The spine screw assembly includes a bone fastener with a head having a groove that removably accepts a clip. The clip acts to retain the head of the bone fastener in the receiver member.