Spinal Stabilization Collar Bore Profile for Dynamic Rod Motion
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Solution Overview
Problem
Existing dynamic spinal stabilization systems often stiffen the spine and limit movement, leading to undesirable loadings on nearby vertebrae, and there is a need for approaches that allow for easy installation while maintaining robustness.
Innovation Solution
A dynamic spinal stabilization assembly featuring a rod assembly with a sliding collar and elastic elements, allowing the rod to move relative to bone anchoring elements, with a bore profile designed to minimize binding and facilitate sliding motion, and adjustable configuration for varying kinematic responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid spinal stabilization structure is used, then structural stability is improved, but spinal mobility and post-operative freedom of movement deteriorate
Solution Approach 1:
The patent implements a dynamic stabilization system where the rod assembly can slide along the bone anchoring elements through a collar mechanism. This allows the spinal stabilization structure to adapt to movement and maintain stability dynamically rather than being rigidly fixed, resolving the contradiction between structural stability and spinal mobility.
Solution Approach 2:
The system changes the rigidity parameter of the stabilization structure by allowing controlled sliding motion between the rod and bone anchoring elements. The collar with its bore profile enables variable contact conditions that adjust the effective rigidity based on operational needs, maintaining stability while permitting movement.
2Ease of operation
If a dynamic stabilization system allowing movement is used, then spinal mobility is improved, but structural robustness and reliability deteriorate
Solution Approach 1:
The dynamic collar mechanism provides controlled movement capability while maintaining structural robustness through the fixed mating of the collar to the bone anchoring element and the sliding action that distributes loads effectively. The system remains reliable because the movement is controlled and the structural connection is maintained.
Solution Approach 2:
The collar acts as an intermediary component between the rod assembly and the bone anchoring element. It mediates the interaction by providing a controlled sliding interface that allows movement while maintaining structural integrity and load transfer, thus preserving reliability during dynamic operation.
3Reliability
If conventional rigid fixation is used, then healing promotion is improved, but load distribution to nearby vertebrae deteriorates
Solution Approach 1:
The system changes the load distribution parameter by allowing controlled movement and sliding action that distributes mechanical loads more favorably across the spinal segment. This prevents excessive load concentration on nearby vertebrae while still providing sufficient stabilization for healing.
Solution Approach 2:
The dynamic sliding mechanism allows the stabilization structure to adapt to loading conditions and distribute forces dynamically rather than creating fixed stress concentrations. This dynamic load distribution reduces harmful loadings on adjacent vertebrae while maintaining healing promotion.
Data Source
AI summary
A dynamic spinal stabilization assembly includes at least one mounting collar with a bore therethrough along a longitudinal axis, and a spinal rod slidably extending through the bore. The bore includes a medially disposed first section of reduced size that tapers both inwardly and outwardly relative to the axis, and respective end sections of relatively larger size. The bore may be defined by an interior wall that convexly curves toward the axis in the first section, advantageously with a constant non-zero radius of curvature. The bore profile helps minimize potential binding that may occur between the collar and the rod. The rod is coupled to bone anchoring elements, with at least one such connection being via the collar.