Posterior Lumbar Joint Prosthesis with Adaptable Anchors
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Solution Overview
Problem
Current spinal prosthetics fail to adequately address the need for preserving intervertebral mobility while reducing friction between degenerated joint facets, and they often have issues with anchor quality and variability in anatomy, leading to suboptimal kinematics and functional degradation.
Innovation Solution
A posterior lumbar joint prosthesis with adaptable vertebral anchors and linkage mechanisms that allow for flexion, extension, lateral flexion, and rotation, featuring pedicular screws, connectors, and sleeves that pivot and translate to accommodate anatomical variations, ensuring intuitive installation and maintaining mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid anchors are used to ensure stable fixation, then anchoring strength is improved, but adaptability to anatomical variations deteriorates
Solution Approach 1:
The prosthesis employs dynamic components including a ball joint connecting the superior and inferior members, allowing rotational movement. The inferior member can pivot relative to the inferior pedicular screw within a conical range, enabling the rigid anchor structure to adapt to anatomical variations while maintaining stable fixation. This dynamic capability resolves the contradiction between rigidity for strength and flexibility for adaptability.
2Ease of operation
If friction between joint facets is reduced through prosthesis, then mobility is improved, but stability deteriorates
Solution Approach 1:
The ball joint mechanism allows controlled movement between superior and inferior members while maintaining structural integrity. The prosthesis preserves physiological range of motion including flexion, extension, lateral flexion, and rotation, yet the interconnected rigid structure with pedicular anchors provides sufficient stability, resolving the trade-off between mobility and stability.
3Adaptability or versatility
If complex anchoring systems are used to adapt to anatomical variations, then adaptability is improved, but device complexity deteriorates
Solution Approach 1:
Rather than using complex adjustable anchoring systems, the invention employs a dynamic ball joint mechanism that passively adapts to anatomical variations through controlled movement. The inferior member pivots within a conical range defined by the ball joint geometry, providing adaptability without requiring complex active adjustment mechanisms, thus resolving the contradiction between adaptability and simplicity.
Data Source
AI summary
There is provided a posterior lumbar joint prosthesis which includes prosthetic elements reproducing the movements of the joint facets and vertebral anchors which adapt to the variations in the anatomy of vertebra. In use, the prosthesis has lower and upper connectors on each side of the lumbar vertebra. The lower connectors are coupled with, and pivotably mounted onto, respective lower pedicular screws, and a member defining a member axis links lower and upper connectors on each side of the lumbar vertebra. Upon lateral flexion of one of the upper and lower vertebrae relative to the other, each lower connector is capable of multiaxis pivotable movement relative to the respective lower pedicular screws such that each member is capable to pivot with respect to (i) the axis of the lower screw, (ii) a first axis intersecting the lower screw and the lower connector, and/or (iii) an axis intersecting the above first axis and the lower screw, while the member can also move along the member axis.