Semi-Flexible Spinal Screw Fixation Mechanism
Solution Overview
Problem
Existing spinal fixation devices require complex locking mechanisms with multiple components, leading to increased size, manufacturing costs, and potential soft tissue irritation, while existing polyaxial screws struggle to provide a strong and secure lock without movement, which is crucial for spinal stabilization and fusion.
Innovation Solution
A screw and rod fixation assembly using a semi-flexible material for the fixing mechanism that inherently grips the screw head through compression forces, eliminating the need for additional components and allowing secure locking without manipulation, with a design that minimizes size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If complex locking mechanisms with multiple components are used to secure polyaxial screws, then the screw locking strength is improved, but the device size increases and soft tissue irritation worsens
Solution Approach 1:
The patent extracts and eliminates unnecessary locking components from the spinal fixation system. Instead of using complex multi-component locking mechanisms, the invention uses a simplified single-component design where the rod itself provides the locking function through its interaction with the screw head, removing extraneous parts that contribute to soft tissue irritation while maintaining secure screw fixation
Solution Approach 2:
The patent merges the locking function into the rod structure itself rather than requiring separate locking components. The rod is designed to directly engage and secure the screw head through its geometric configuration, combining what were previously separate functions (rod support and screw locking) into a unified structure that reduces overall device complexity and tissue irritation
2Reliability
If additional locking components are added to secure the screw head, then the reliability of screw fixation is improved, but the device complexity increases
Solution Approach 1:
The patent implements a self-locking mechanism where the rod's geometric configuration automatically secures the screw head without requiring additional active locking components. The rod's shape and positioning create inherent mechanical interference that prevents screw head displacement, allowing the structure to serve its own locking function rather than requiring separate locking mechanisms
Solution Approach 2:
Instead of using components that actively lock the screw (such as set screws or locking nuts), the invention inverts the approach by designing the rod to passively constrain the screw head through its geometry. The locking action is achieved through the rod's shape and position rather than through active mechanical engagement components
3Stability of the object's composition
If multiple locking components are used to secure the rod and screw, then the stability of spinal fixation is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple locking functions into a single rod component, eliminating the need for separate locking nuts, set screws, or other fastening elements. This consolidation reduces the total part count, simplifies manufacturing processes, and lowers material costs while maintaining the stability required for effective spinal fixation through the rod's integrated geometric design
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 solution provides a strong, secure, and simplified locking mechanism that reduces the size of spinal implants, minimizes soft tissue irritation, and ensures stable fixation without additional components, enhancing the effectiveness of spinal stabilization and fusion procedures.
Implementation Method 1
The fixing mechanism (18) is made of a semi-flexible material that creates compression forces onto the screw head (14)
Data Source
Figure 1A~3
Figure 4~6
Figure 7~9
AI summary
The present invention provides for a screw and rod fixation assembly for fixing a screw and, optionally, a rod. The screw and rod fixation assembly includes a screw, fixing mechanism, a substantially annular ring, rod seating mechanism, and locking mechanism. The present invention also provides for a fixing mechanism for fixing a screw, wherein the fixing mechanism further includes an inner surface wall having a gripping portion and a non-gripping portion. Further, the present invention provides for a substantially annular ring for guiding and providing mechanical and frictional force to a screw head. Additionally, the present invention provides for a rod seating mechanism operatively engaged to the screw head and including at least one flexible portion capable of being compressed against a portion of a rod therein. Finally, the present invention provides for a locking mechanism for engaging the rod and the rod seating mechanism. The locking mechanism includes a deflecting mechanism for deflecting the at least one flexible portion of the rod seating mechanism against and around the rod as the locking mechanism further engages the at least one flexible portion of the rod seating mechanism.