Intervertebral Disk Prosthesis with Elastic Core and Guide Pins
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Solution Overview
Problem
Existing intervertebral disc prostheses, particularly in the cervical spine, restrict natural movement and fail to adequately absorb and distribute head loads, leading to potential dislocation and increased risk of failure due to lack of damping, causing load peaks and discomfort.
Innovation Solution
An intervertebral disc prosthesis comprising a caudal plate with a recess and an elastic core connected in a form-fitting manner, allowing six degrees of freedom with flexion, extension, lateral bending, rotation, translation, and stiffness, while the cranial plate rests on the core without a firm connection, using viscoelastic materials like silicone or PCU, and guide pins engaging in complementary guide contours to facilitate movement without additional components or fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the cranial plate is firmly connected to the elastic core, then structural stability is improved, but natural movement with six degrees of freedom is restricted
Solution Approach 1:
The prosthesis is divided into three functional segments: caudal plate (firmly connected to core), elastic core (provides cushioning and movement), and cranial plate (movably connected via guide pins). This segmentation allows each component to fulfill its specific function - the caudal plate provides stable anchoring, the core provides shock absorption and natural movement, and the cranial plate allows controlled motion while maintaining stability.
Solution Approach 2:
The connection between the cranial plate and elastic core is designed to be dynamic rather than static. Guide pins with guide contours enable the cranial plate to move relative to the core in six degrees of freedom, allowing the prosthesis to adapt to natural spinal movements while maintaining structural integrity through the elastic core's damping properties.
2Strength
If additional materials or components are used to connect the caudal plate to the elastic core, then connection strength is improved, but device complexity increases
Solution Approach 1:
The connection between the caudal plate and elastic core is achieved by integrating the core directly into the recess of the caudal plate during manufacturing, eliminating the need for separate fastening components. The core's elastic properties combined with the recess geometry create a strong, unified connection that simplifies the overall device structure while maintaining connection strength.
3Stability of the object's composition
If the prosthesis uses rigid connections between plates and core, then fixation stability is improved, but load distribution and cushioning are worsened
Solution Approach 1:
The elastic core changes its mechanical parameters dynamically - it provides firm support and stability when needed (maintaining fixation) while simultaneously absorbing and distributing loads through its elastic deformation (reducing load peaks). This parameter change allows the same component to fulfill both contradictory requirements of stability and cushioning.
Solution Approach 2:
The prosthesis combines rigid materials (metal or ceramic plates) with elastic material (silicone or PCU core) to create a composite structure. The rigid plates provide structural stability and fixation, while the elastic core provides shock absorption and load distribution, together resolving the contradiction between stability and cushioning.
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 design allows for natural spinal movement with reduced load on ligaments and muscles, preventing dislocation and ensuring primary stability by absorbing and distributing head loads, thus reducing the risk of prosthesis failure and improving patient comfort.
Implementation Method 1
the core being made of a viscoelastic material, in particular silicone or PCU
Implementation Method 2
The cranial plate rests on the elastic core. Rather, the cranial plate rests on the elastic core. Therefore, a prosthesis consisting of two plates and an elastic core is provided, enabling natural movement of the spine
Implementation Method 3
the recess has an undercut at least in sections. The core is preferably injected or cast into the recess, particularly by means of a primary forming process, and especially preferably by means of a plastic injection molding or vacuum casting process. The injection or casting of a core into the recess, particularly into a recess that has an undercut at least partially, creates a positive-locking connection.
Implementation Method 4
the cranial plate has at least one guide pin that movably engages in a guide contour of the core
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to an intervertebral disk prosthesis (10), comprising a caudal plate (20), a cranial plate (30), and an elastic core (40) formed between the caudal plate (20) and the cranial plate (30), wherein the caudal plate (20) has a cavity (25) on the side (21) facing the cranial plate (30), wherein the core (40) is integrally connected to the cavity (25) in the caudal plate (20).