3D-Printed Cervical Standalone Implant With Rotatable Screw Lock
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Solution Overview
Problem
Existing intervertebral implants face issues such as screw openings directing screws at shallow angles, requiring two separate components for assembly, and locking mechanisms that can become disengaged over time, leading to instability and potential backout of screws.
Innovation Solution
A monolithic intervertebral implant with a locking element that is integrated through additive manufacturing, featuring rotatable and secure fastener openings and a locking mechanism that prevents screw backout, allowing for single-step assembly and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing cage designs with screw openings are used, then screw fixation is achieved, but the screw trajectory is directed at a shallow angle which is undesirable
Solution Approach 1:
The patent combines the cage body and locking mechanism into a single integrated component. The locking mechanism is built into the cage structure itself, eliminating the need for separate locking components and allowing for optimized screw trajectories without compromising locking functionality.
Solution Approach 2:
The locking mechanism incorporates a rotatable element that can move between locked and unlocked positions. This dynamic feature allows the surgeon to insert screws at optimal angles and then secure them by rotating the locking element, providing both operational flexibility and trajectory precision.
2Manufacturing precision
If protruding surfaces are added to aid screw trajectory, then desired screw trajectory is achieved, but two separate components are required for assembly
Solution Approach 1:
The patent integrates the trajectory-guiding features directly into the cage body structure. The locking mechanism and trajectory control elements are merged into a single component, eliminating the need for separate assembly of multiple parts while maintaining precise screw trajectory control.
3Reliability
If locking mechanism is exposed on one side of the cage, then locking functionality is achieved, but the mechanism may become disengaged over time
Solution Approach 1:
The locking mechanism is integrated into the cage structure with the locking element positioned within the cage body. This integration protects the locking mechanism from disengagement while maintaining accessibility through the cage structure, improving both reliability and operational ease.
4Strength
If standalone cage design with multiple screws is used, then fixation is achieved, but assembly requires multiple separate components
Solution Approach 1:
The patent combines the cage body and locking mechanism into a single integrated component. The locking mechanism is built into the cage structure itself, eliminating the need for separate locking components and simplifying assembly while maintaining strong vertebral fixation through multiple screws.
Data Source
AI summary
In one embodiment, an intervertebral implant includes a body and a locking element. The body includes a leading surface and a trailing surface opposite the leading surface. The body also includes first and second bone fastener passageways through the implant body and a cavity in between the first and second passageways. The cavity includes a trailing wall that separates the cavity from the trailing surface. The locking element is disposed in the cavity such that part of the locking element is visible through an access opening in the trailing wall so that the locking element may be rotated from outside of the implant. In a first rotational position, a first part of the locking element is located within one of the first and second passageways and in a second rotational position, the first part of the locking element is inside the body covered by the trailing wall.