Vertebral Rod With Elastic Bumper For Variable Resistance
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Solution Overview
Problem
Current vertebral rod systems lack dynamic stabilization mechanisms that provide variable resistance to movement, which is essential for maintaining spinal alignment and reducing stress on adjacent vertebral members during bone-graft healing and motion.
Innovation Solution
The vertebral rod assembly incorporates an intermediate section with a curved interior surface and an elastic bumper, which provides variable resistance to movement by switching between compression and tension, limiting the range of motion and distributing loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid rod system is used to maintain spinal alignment, then structural support is improved, but the ability to provide dynamic stabilization and variable resistance to movement is lost
Solution Approach 1:
The rod is divided into multiple sections: rigid end sections for structural support and an intermediate section with variable stiffness for dynamic stabilization. This segmentation allows different parts of the rod to perform different functions - the rigid ends provide strength while the compliant intermediate section provides adaptability to spinal motion
Solution Approach 2:
The rod transitions from a static rigid structure to a dynamic system with variable stiffness. The intermediate section's ability to change its mechanical properties allows the rod to adapt to different spinal motions and loading conditions, providing variable resistance to movement while maintaining overall structural integrity
2Stability of the object's composition
If spinal fusion is performed to inhibit relative motion between vertebral members, then stability is improved, but motion preservation is lost
Solution Approach 1:
The rod's stiffness parameter is varied along its length, with the intermediate section having lower stiffness to allow motion while the end sections have higher stiffness for stability. This gradient in stiffness parameters enables the rod to provide stabilization without completely inhibiting physiological motion
3Stress or pressure
If rods are used to redirect stresses over a wider area, then load distribution is improved, but stress transfer to adjacent vertebral members increases
Solution Approach 1:
The intermediate section acts as a stress-distributing intermediary between the rigid end sections and the adjacent vertebral members. It gradually transitions the load, preventing abrupt stress transfers to adjacent members while maintaining wide load distribution across the instrumented vertebrae
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 configuration offers dynamic stabilization during normal spinal motion, reduces stress on vertebral members, and prevents excessive movement, thereby aiding in bone-graft healing and maintaining spinal alignment.
Implementation Method 1
An elastic bumper may be disposed in the pocket and formed of a different material than the first and second rod sections and the intermediate section. The elastic bumper may be attached to the intermediate section at multiple locations along a portion of the curved interior surface that is offset from the common centerline. The intermediate section and the elastic bumper may be configured to provide variable resistance to movement of the first and second sections.
Data Source
AI summary
The present application is directed to vertebral rods and methods of use. In one embodiment, the rod includes upper and lower sections that are separated by an intermediate section. The intermediate section may include one or more members, and may have a variety of configurations. An elastic member may be positioned within the intermediate section. The intermediate section and the elastic member may provide for variable resistance during movement of the upper and lower sections. In one embodiment, the resistance increases the further away the upper and lower sections move from a first orientation.