Modular Pedicle Screw With Double Ring Retainer
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Solution Overview
Problem
Current spinal implant systems face challenges in securely attaching vertebral rods to bone fasteners, particularly in resisting disengagement and ensuring stable fixation during surgical procedures for spinal disorders, which can lead to instability and complications.
Innovation Solution
A modular pedicle screw system with a double ring configuration and expansion mechanism that includes a receiver, retainer, and compression insert, allowing for secure engagement and resistance to disengagement through a mechanism that prevents unintentional separation of components, enabling minimal force assembly without instrumentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional spinal implant system is used to attach vertebral rods to bone fasteners, then the assembly process is complex and requires instrumentation, but the risk of disengagement and instability remains high
Solution Approach 1:
The bone fastener is divided into multiple components including a receiver, retainer, and compression insert, each performing specific functions. The retainer features a groove system that segments the engagement path, allowing controlled assembly while preventing disengagement. This segmentation enables reliable attachment through a simplified single-step process without requiring complex instrumentation.
Solution Approach 2:
The compression insert is nested within the receiver, and the retainer is positioned within the receiver to engage the rod. This nested configuration allows multiple functional elements to be integrated in a compact structure, enabling secure attachment while simplifying the overall assembly process by eliminating the need for separate instrumentation steps.
2Reliability
If a secure engagement mechanism is implemented to prevent disengagement, then the attachment becomes more reliable, but the assembly process becomes more complex
Solution Approach 1:
The retainer is pre-configured with a groove system that defines the engagement path before the rod is inserted. The compression insert is pre-positioned within the receiver to provide initial structural support. This preliminary configuration ensures that when the rod is inserted, it automatically engages the retainer in the correct position, providing resistance to disengagement while maintaining ease of assembly through a single intuitive motion.
3Reliability
If instrumentation is used to ensure stable fixation, then the attachment reliability improves, but the procedural complexity and time increase
Solution Approach 1:
The bone fastener system is designed to be self-assembling through a snap-fit mechanism. The retainer automatically engages the rod when inserted into the receiver, and the compression insert provides self-contained structural support. This self-service design achieves stable fixation without requiring external instrumentation or multiple procedural steps, significantly reducing assembly time while maintaining high reliability.
Data Source
AI summary
A bone fastener comprises a first member defining an implant cavity and a plurality of adjacent grooves. A first band is configured for disposal within the grooves. A second band is configured for disposal within the grooves. A second member is configured to penetrate tissue and includes a head engageable with the first band to provisionally connect the members. The second band is moveable for disposal adjacent the first band to fix connection of the members. Implants, systems, instruments and methods are disclosed.