Dynamic Stabilization System With Closed Ring Link Member
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Solution Overview
Problem
Conventional spinal fixation methods using rigid rods cause stress shielding and inadequate load distribution, leading to adverse side effects, and existing dynamic stabilization devices lack sufficient torsional stiffness and biomechanical compliance.
Innovation Solution
A dynamic stabilization system comprising a pair of pedicle screws and a link member with a closed ring section that provides adjustable stiffness under compressive, tensile, and torsional loads, allowing for controlled deformation and harmonious load-sharing between spinal structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid metallic rods are used for spinal fixation, then stabilization of the spine is achieved, but stress shielding and adverse loading on spinal structures occur
Solution Approach 1:
The patent applies the dynamics principle by replacing rigid rods with dynamic stabilization devices that incorporate spring components. These springs allow controlled motion and deformation, enabling the system to adapt to physiological movements while maintaining stabilization. The spring mechanism provides dynamic compliance that reduces stress shielding effects while preserving spinal stability.
Solution Approach 2:
The patent implements parameter changes by modifying the mechanical properties of the stabilization system. Specifically, it changes from rigid (high stiffness) to compliant (lower stiffness) through the introduction of spring elements with tuned springback properties. This parameter change allows the system to provide appropriate stiffness in flexion-extension, lateral bending, and compression-distraction while reducing adverse loading effects.
2Object-generated harmful factors
If titanium rods with lower elastic modulus are used, then some stress shielding is reduced, but the biomechanical advantage is minor and facets are not sufficiently spared
Solution Approach 1:
The patent goes beyond material composition changes by fundamentally changing the structural parameter of the rod system. Instead of merely selecting materials with different elastic moduli, it introduces spring components that provide dramatically higher compliance while maintaining stabilization effectiveness. The tuned springback properties enable reliable stress distribution without compromising stabilization.
3Adaptability or versatility
If helical spring components are added to rods, then flexion-extension compliance is improved, but torsional stiffness is insufficient
Solution Approach 1:
The patent applies local quality by designing spring components with specific geometric characteristics optimized for different loading conditions. The springs are configured with particular wire diameters, coil diameters, and active coil counts to provide appropriate stiffness in different directions. This localized optimization ensures sufficient torsional stiffness while maintaining flexion-extension compliance.
Solution Approach 2:
The patent employs composite construction by combining rod elements with spring components to create a hybrid structure. This composite system integrates the strength and stiffness of rigid rods with the compliance and flexibility of spring elements, achieving a balance between torsional strength and multi-directional flexibility that neither component could provide alone.
4Reliability
If a compromise between stiffness and compliance is designed, then load-sharing between biological structures is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by integrating the spring components directly into the rod structure to form a unified dynamic stabilization device. Rather than using separate rigid rods and spring elements that require complex assembly, the spring mechanism is incorporated within the rod itself, simplifying the overall system while achieving the desired load-sharing characteristics.
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 system reduces stress shielding and adverse loading on spinal structures by offering a biomechanical compromise between stiffness and compliance, effectively stabilizing the spine while minimizing harm to surrounding tissues and providing controlled rotational and translational flexibility.
Implementation Method 1
a link member adapted to interconnect the anchor members, the link member comprising a first end portion, a second end portion and a closed ring therebetween
Data Source
AI summary
The present invention relates to a dynamic stabilization system (DSS) having at least one rod having a ring formed therein (“the spring”) and a pair of pedicle screws adapted for fixation to separate vertebrae.