Dual Spring Posterior Stabilization Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current spinal stabilization techniques either restrict motion between vertebrae, leading to additional stress on adjacent levels, or require complex alignment and sizing of articulating surfaces, failing to effectively mimic natural facet joint function.
Innovation Solution
A posterior dynamic stabilization device featuring a dual-helix titanium spring with a polymer core, adjustable for stiffness, and attachment features to bone anchors, allowing natural elongation and compression while preventing soft tissue ingrowth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fusion techniques are used to stabilize the spine, then pain relief is achieved, but motion between vertebrae is prevented leading to additional stress on adjacent levels
Solution Approach 1:
The patent employs a dynamic stabilization device with a spring element that allows controlled motion between vertebrae while providing stabilization. The spring element enables the device to adapt to physiological movements, maintaining stability without completely restricting motion, thereby avoiding stress concentration on adjacent levels while still providing pain relief.
2Adaptability or versatility
If articulating facet replacement devices are used to restore normal function, then facet joint function is mimicked, but the facet joints must be resected and alignment is challenging
Solution Approach 1:
The patent extracts the articulating surfaces from the replacement device, allowing the natural facet joints to be preserved while the spring element provides the necessary stabilization. This eliminates the need for facet resection and complex alignment procedures, as the device works with the existing anatomical structures rather than replacing them.
Solution Approach 2:
The spring element's mechanical properties can be adjusted to match the physiological characteristics of the facet joints, providing adaptable stabilization without requiring precise alignment. The spring constant and other parameters can be modified to accommodate various anatomical configurations, simplifying the implantation process.
3Strength
If a rigid rod is used for spinal stabilization, then structural support is provided, but natural spinal elongation and compression are restricted
Solution Approach 1:
The patent replaces the rigid rod with a spring element that has flexible characteristics. The spring element can elongate and compress to accommodate natural spinal movements while still providing the necessary structural support and stabilization. This flexible approach allows physiological motion to occur without compromising the stabilizing function.
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 device regulates physiologic spinal elongation and compression, preserving a natural center of rotation and preventing tissue ingrowth, thereby providing effective dynamic stabilization with adjustable stiffness to accommodate various anatomical needs.
Implementation Method 1
an intermediate spring portion comprising first and second springs, each spring having a helical intermediate portion
Implementation Method 2
The hollow central part of said member is filled at rest with a viscoelastic cushioning product cast in inter-thread overflow
Data Source
AI summary
A Posterior Dynamic Stabilization (PDS) device that regulates physiologic spinal elongation and compression. Regulation of elongation and compression are critical requirements of Posterior Dynamic Stabilization devices. Elongation and compression of the device allow the pedicles to travel naturally as the spine flexes and extends. This interpedicular travel preserves a more natural center of rotation unlike some conventional PDS devices that simply allow bending. The device incorporates two components: 1) a spring that allows elongation/compression, and 2) a polymer core component that serves to increase the stiffness of the device in shear, bending, and tension, and also prevents soft tissue ingrowth.