Cervical Plate Cam Feedback Mechanism for Secure Screw Locking
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Solution Overview
Problem
Existing bone plate systems with screw blocking mechanisms do not effectively lock bone screws in place after implantation, allowing screws to loosen and potentially back out, and lack adequate feedback for surgeons during insertion and locking processes.
Innovation Solution
A cervical bone plate with a movable blocker and cam mechanism that locks the bone screw in place after implantation, providing tactile and visual feedback through a cam system, ensuring the screw is securely positioned and preventing further loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking mechanism is used to prevent screw backout, then screw security is improved, but the mechanism does not provide feedback to the surgeon during insertion and locking processes
Solution Approach 1:
The patent applies feedback by incorporating a cam mechanism that provides tactile feedback to the surgeon during screw insertion and locking. The cam rotates and engages with the blocker, creating audible and tactile signals that indicate when the screw is properly positioned and locked, thereby compensating for the lack of visual feedback in a minimally invasive procedure
2Reliability
If a blocker is used to prevent screw backout, then screw security is improved, but the blocker cannot be expanded after implantation to lock the screw
Solution Approach 1:
The patent applies dynamics by designing a blocker that transitions from a static blocking position to an expanded locked position. The blocker is initially positioned to allow screw insertion, then expands outward to engage with the cam mechanism, providing a dynamic locking action that secures the screw after implantation
Solution Approach 2:
The patent applies preliminary action by pre-positioning the blocker in a retracted state that allows easy screw insertion. Before final locking, the blocker is expanded to engage the cam mechanism, ensuring that the screw is secured in the desired position before the locking action occurs
3Reliability
If a cam mechanism is added to provide feedback and locking, then screw security and feedback are improved, but device complexity increases
Solution Approach 1:
The patent merges the blocking function and the locking function into a single integrated mechanism. The blocker and cam work together as a unified system where the blocker provides both the initial blocking function and the final locked position, while the cam provides both feedback and the locking action, thereby reducing overall device complexity
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
The bone plate system effectively locks bone screws in place, preventing loosening and providing clear feedback to surgeons during insertion, ensuring secure fixation and preventing screw backout.
Implementation Method 1
a cam having an open orientation at which the blocker is permitted to move and a close orientation at which the blocker is substantially prevented from moving from the blocking position
Data Source
AI summary
A bone plate having at least one screw hole adapted to receive a bone screw, a blocker having a blocking end for blocking a bone screw from further backout of bone the blocker being predisposed in a blocking position wherein the blocking end at least partially overlaps a portion of the screw hole, the blocker being moveable from the blocking position by contact with the bone screw during insertion of the bone screw into the screw hole, and a blocker fixation element having an open orientation at which the blocker can move from the blocking position and a closed orientation preventing substantial movement of the blocker from the blocking position. The blocker fixation element cannot be moved to the closed orientation unless the screw head passes the blocker, thereby revealing that the blocker fixation element is in position to prevent substantial movement of the blocker.