Partial Endoprosthesis for Cervical Vertebrae Motion Preservation
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Solution Overview
Problem
Current devices for treating cervical vertebral painful conditions through motion preservation often require invasive anterior approaches, risking neurological injuries due to the use of screws that can damage thin articular processes, and existing solutions are not suitable for preserving relative movement between cervical facets.
Innovation Solution
A partial endoprosthesis device with an elongated articular portion and flexible primary stabilization elements that are osteointegrable, allowing for implantation between articular facets without damaging the thin cervical vertebrae, providing stable integration and motion preservation through a less invasive procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screws are used to fasten the device to the external surfaces of the laminae for primary stabilization, then the device achieves reliable primary stabilization, but the thin articular processes are damaged and weakened
Solution Approach 1:
The invention removes the screws from the stabilization mechanism entirely. Instead of using external screws that penetrate and damage the thin articular processes, the device achieves primary stabilization through the elastic deformation of its own body during insertion. The device is compressed in the insertion direction and stores elastic energy, which automatically provides stabilization without requiring invasive fastening elements.
Solution Approach 2:
The invention replaces the mechanical screw-fastening system with an elastic deformation-based stabilization system. The device utilizes elastic potential energy stored during compression to achieve self-stabilization, substituting the need for mechanical fasteners that would otherwise damage the delicate cervical vertebrae structures.
2Ease of operation
If an anterior approach is used to implant intersomatic devices at the cervical level, then the device can be implanted, but there is a risk of neurological injuries
Solution Approach 1:
The invention inverts the traditional anterior approach by enabling posterior or lateral implantation. The device is designed to be inserted from the back or side of the cervical spine, reversing the conventional surgical approach. This inversion allows access to the intersomatic space without requiring anterior dissection, thereby avoiding the neurological structures located in the anterior cervical region.
Solution Approach 2:
The device acts as an intermediary that enables posterior/lateral access to the anterior cervical intersomatic space. Through its specific geometric design and elastic deformation characteristics, the device can be introduced from a safer posterior or lateral trajectory while still achieving its functional position in the intersomatic space, mediating between the safer access route and the required implantation location.
3Stability of the object's composition
If sawtooth-shaped primary stabilization means are used to rigidly connect vertebral bodies, then stable connection is achieved, but the device is not suitable for preserving relative movement between cervical facets
Solution Approach 1:
The invention applies dynamics by designing the device body to undergo elastic deformation during insertion and stabilization. The device transitions from a compressed state during insertion to a stabilized state where the stored elastic energy provides continuous adaptive stabilization. This dynamic behavior allows the device to maintain stability while permitting the physiological relative movements between cervical facets, unlike rigid sawtooth connections.
Solution Approach 2:
The invention utilizes parameter changes through elastic deformation of the device body. The elastic modulus and deformation characteristics are specifically selected to allow the device to adapt its stiffness during the stabilization process, providing firm initial stabilization that gradually transitions to a more compliant state that preserves natural cervical motion.
4Ease of manufacture
If the device thickness is uniform throughout, then manufacturing is simplified, but the device cannot provide progressive stabilization during insertion
Solution Approach 1:
The invention applies asymmetry by making the device thickness non-uniform, with a first thickness at the insertion end and a second, greater thickness at the opposite end. This asymmetric geometry is crucial for the elastic deformation mechanism, as it creates a gradient of stiffness that enables progressive stabilization during insertion. The varying thickness profile allows the thinner insertion end to deform more easily while the thicker end provides structural support.
Solution Approach 2:
The invention implements local quality by assigning different thicknesses to different regions of the device body. The insertion end has a specific thickness optimized for elastic deformation and insertion, while the opposite end has a greater thickness for enhanced stabilization and structural integrity. This local variation in geometric quality optimizes both insertion characteristics and final stabilization effectiveness.
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 effectively stabilizes the articular processes without damaging them, allows for easier implantation, and preserves the natural motion of the cervical vertebrae, reducing the risk of neurological injuries and improving postoperative outcomes.
Implementation Method 1
the first face, becoming integral with the first articular facet by osteointegration
Implementation Method 2
comprising an elastic body having a first end and a second end axially opposite to each other
Data Source
AI summary
A partial endoprosthesis device preserves the motion of a vertebral joint for implant into a spinal segment and includes an articular portion having a thickness that increases in the direction of introduction between the articular facets. The articular portion is elongated along a longitudinal axis with a opposite first and second faces. The first face has a central protrusion that is configured so that, by implanting the device with the articular portion inserted between an upper articular facet of a lower vertebra and a corresponding lower articular facet of upper vertebra adjacent to the lower vertebra, and with the first face in contact with either the upper or lower articular facet, and with the second face in contact with the other articular facet, the articular portion, with the first face, pushes against the first articular facet and finally becomes integral by osteointegration with the lower articular facet.