Lumbar Arthroplasty Prosthesis with Guiding and Damping Axis
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Solution Overview
Problem
In cases of degenerative lumbar spine pathologies, fusion of lumbar vertebrae can lead to destabilization and subsequent deterioration of adjacent spinal levels, causing complications such as degeneration of overstimulated spinal levels due to fusion.
Innovation Solution
A total joint arthroplasty prosthesis with connectors fixed in spinal pedicles by anchoring screws, upper and lower connecting elements, and guiding and damping means that define a rotation and sliding axis to limit stress on screws, allowing controlled flexion, extension, and lateral inflexion movements while stabilizing the spinal segment, using cables and elastomer stops for movement limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fusion of superjacent and subjacent lumbar vertebrae is performed to stabilize the spinal segment, then stability of the spinal segment is improved, but the adjacent spinal levels become overstimulated and deteriorate
Solution Approach 1:
The prosthesis divides the spinal stabilization into segments: connectors fixed in pedicles of superjacent and subjacent vertebrae, with connecting elements between them. This segmentation allows localized stabilization of the affected segment while preserving motion at adjacent levels, preventing overstimulation and deterioration of neighboring spinal structures.
Solution Approach 2:
The prosthesis incorporates dynamic stabilization through guiding and damping means that allow controlled movements (flexion, extension, lateral inflexion) around a rotation and sliding axis. This dynamic design provides stability to the spinal segment while maintaining physiological motion, preventing the rigid fusion that causes adjacent level deterioration.
2Reliability
If dynamic stabilization devices are used in young patients with reversible lumbar vertebrae deterioration, then reversibility of deterioration is improved, but the device complexity increases
Solution Approach 1:
The prosthesis is segmented into modular components: connectors, upper and lower connecting elements, guiding and damping means, and limitation means. This modular segmentation simplifies the overall device while maintaining dynamic stabilization capability, making it suitable for young patients with reversible deterioration.
Solution Approach 2:
The prosthesis acts as an intermediary device between the superjacent and subjacent vertebrae, providing controlled motion and stability. This intermediary function allows the vertebrae to move dynamically while maintaining alignment, facilitating reversibility of deterioration without requiring complex surgical intervention.
3Object-affected harmful factors
If fusion is performed to eliminate hypertrophied bone elements and decompress spinal marrow and nerve roots, then decompression is improved, but destabilization of the spinal segment occurs
Solution Approach 1:
The prosthesis provides dynamic stabilization that maintains spinal segment stability while allowing controlled movements. This dynamic design prevents the destabilization that occurs with rigid fusion, enabling the spinal segment to remain stable after decompression of hypertrophied bone elements while preserving physiological motion.
Solution Approach 2:
The prosthesis changes the mechanical parameters of the spinal segment by introducing connectors and connecting elements with specific rigidity and motion characteristics. This parameter change allows the spinal segment to maintain stability after decompression while accommodating the necessary movements to prevent adjacent level deterioration.
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 prosthesis effectively stabilizes the affected spinal segment while protecting adjacent levels from deterioration by allowing controlled movements and reducing stress on anchoring screws, thereby preventing further spinal degeneration.
Implementation Method 1
elastomer stops whose elastic deformations enable the displacements of said guiding element inside said oblong groove to be limited without constraint
Implementation Method 2
guiding and damping means and said upper and lower connecting elements being constructed with relation to each other so as to define at least one rotation and sliding axis C situated at the level of the upper superjacent vertebra Va
Implementation Method 3
limitation means that are comprised of a cable connecting the connectors between each other
Data Source
AI summary
The total arthroplasty joint prosthesis includes connectors (2, 4) fixed in the pedicles Vp of the spinal levels by anchoring screws (3), upper and lower connecting elements (5, 6) connecting the connectors (2, 4) to each other, and guiding and damping element (7) connecting the upper and lower connecting elements (5, 6), the guiding and damping element (7) and the upper and lower connecting elements (5, 6) being constructed with relation to each other so as to define at least one rotation and sliding axis C situated at the level of the upper superjacent vertebra Va of the instrumented segment Sr in order to limit the stresses on the anchoring screws (3) ensuring fixation of the connectors (2) in the superjacent vertebra Va.