Pedicle Screw Locking via Multi-Clamp Rod Engagement
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Solution Overview
Problem
Prior pedicle screw designs fail to provide sufficient force to securely fix the screw relative to the housing, leading to potential disengagement during spinal fusion procedures.
Innovation Solution
The pedicle screw design includes a screw body, housing, clamps, and a set screw, where the set screw applies force to the rod, which engages the clamps to frictionally secure the ball-shaped member against the clamps' inner surfaces, enhancing locking capability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a set screw is used to apply downward force on the rod, then the pedicle screw should be fixed relative to the housing, but prior designs do not provide sufficient force to prevent disengagement
Solution Approach 1:
The clamp assembly is divided into multiple clamps (first clamp, second clamp, third clamp) that can independently engage the rod at different locations. This segmentation allows distributed force application along the rod, increasing total locking capability while maintaining reliability against disengagement.
Solution Approach 2:
The clamps are arranged in a longitudinal sequence along the rod, transitioning from a single-point contact to a multi-point distributed contact system. This dimensional arrangement along the rod's length creates multiple engagement zones, significantly increasing the total frictional force and preventing disengagement more effectively.
2Strength
If multiple clamps are used to engage the rod, then locking strength increases, but device complexity increases
Solution Approach 1:
Multiple clamps are merged into a single integrated clamp assembly that functions as one unified locking mechanism. The clamps are positioned side-by-side and work together to engage the rod, distributing force while maintaining a compact, organized structure that does not excessively increase complexity.
Solution Approach 2:
Each clamp in the assembly serves multiple functions: engaging the rod, distributing force, and contributing to the overall locking mechanism. This multi-functionality allows the system to achieve high locking strength through several simple, identical components rather than one complex structure.
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
This design significantly increases the locking strength and stability of the pedicle screw, preventing disengagement and ensuring effective fixation during spinal fusion procedures.
Implementation Method 1
the rod engaging the plurality of clamps to frictionally engage the ball-shaped member against the ball-shaped inner surface of each of the clamps
Data Source
AI summary
Pedicle screws that can include a pedicle screw body, housing, plurality of clamps, rod, and set screw are disclosed herein. The clamps may be positioned side by side inside the lower portion of the housing. When the rod and set screw are provided in the housing, the set screw applies a force on the rod and the rod engages the plurality of clamps, causing the clamps to frictionally engage a head of the pedicle screw between the clamps.