Dynamic Spinal Stabilization Apparatus with Flexible Elements
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Solution Overview
Problem
Conventional spinal fixation devices are overly rigid, leading to complications such as adjacent level syndrome and fusion disease, as they restrict normal spinal movement and cannot accommodate the full range of physiological motion, and existing semi-rigid devices fail to withstand long-term loading conditions.
Innovation Solution
A dynamic stabilization apparatus with elongated members and a central flexible element, along with additional flexible elements, housed within a cylindrical structure that allows for compressive, tensile, angular, shear, and rotational forces, providing a customizable range of motion by varying the material properties of the flexible elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional rigid spinal fixation devices are used to provide stability, then spinal stabilization is achieved, but normal spinal movement is restricted and adjacent level syndrome occurs
Solution Approach 1:
The patent applies the dynamics principle by replacing rigid fixation devices with a dynamic stabilization apparatus that allows controlled movement. The device includes flexible elements and a range of motion mechanism that enables the spine to move within physiological limits while maintaining stability, thereby preventing adjacent level syndrome caused by excessive rigidity.
Solution Approach 2:
The patent changes the rigidity parameter of the fixation device by incorporating flexible elements and adjustable range of motion mechanisms. This allows the device to adapt its stiffness characteristics to match the patient's spinal requirements, providing stability while permitting necessary movement to prevent adjacent level syndrome.
2Reliability
If rigid rods or plates are used to prevent movement of the spinal column, then pain and injury are reduced, but patient mobility decreases and stress increases on adjacent spinal joints
Solution Approach 1:
The dynamic stabilization apparatus allows the spine to move within controlled ranges while maintaining stability. This dynamic approach prevents the complete immobilization caused by rigid rods, thereby preserving patient mobility and reducing stress on adjacent joints while still preventing pain and injury through stable fixation.
3Adaptability or versatility
If semi-rigid fixation devices with spring elements are used to allow greater range of motion, then some movement is permitted, but the devices fail to withstand long-term loading conditions
Solution Approach 1:
The patent employs composite materials by combining flexible elements with structurally sound components in a hybrid device. This composite approach allows the device to provide adequate range of motion through the flexible elements while the robust components ensure long-term durability and resistance to loading conditions, overcoming the limitations of purely spring-based semi-rigid devices.
Solution Approach 2:
The dynamic stabilization apparatus maintains reliability under long-term loading by incorporating mechanisms that adapt to physiological movements. The device's dynamic characteristics allow it to withstand cyclic loading and long-term use while maintaining the desired range of motion, unlike static spring elements that fatigue over time.
4Adaptability or versatility
If flexible spring elements are used to provide range of motion during compression, then axial dampening is achieved, but the spring elements rely on tension load bearing which is not optimal for long-term cyclical loading
Solution Approach 1:
The patent uses composite material construction to create a device where flexible elements provide axial dampening and range of motion, while structurally optimized components handle tension and cyclical loading. This composite approach distributes mechanical stresses more effectively than spring elements alone, improving long-term reliability under cyclical loading conditions.
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 apparatus stabilizes the spine while allowing for a full range of physiological motion, resisting long-term loading conditions and reducing the risk of mechanical failure, thereby improving patient mobility and reducing stress on spinal joints.
Implementation Method 1
A central flexible element having elastic properties within the applicable range of loading, for example loads that the spine experiences
Data Source
AI summary
A dynamic stabilization apparatus comprises elongated members mounted within the proximal end of anchoring devices that are placed in adjacent vertebral bodies. A flexible element having elastic properties within the applicable range of loading, for example loads that the spine experiences, is disposed between the proximal ends of the elongated members. At least one additional flexible element is mounted about the proximal ends of the elongated members adjacent the central flexible element. A housing encapsulates the proximal ends of the members such that the flexible element and the additional flexible elements are contained therein. As compressive, tensile, angular, shear and rotational forces are applied to the elongated members the central flexible element and the additional flexible elements interact with the elongated members and the housing to allow for motion of the elongated members.