Rhomboid Cervical Spinal Implant for Endplate Coverage and Fixation
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Solution Overview
Problem
Conventional spinal implants with rectangular or square configurations fail to conform well to the natural anatomy of the disc space, particularly in the cervical area of the spine, leading to potential protrusion into the spinal canal and suboptimal endplate coverage.
Innovation Solution
The development of rhomboid-shaped spinal implants that orient bone screws approximately perpendicular to the endplates and feature smooth, chamfered edges, allowing for better conformity to the disc space and improved endplate coverage without protrusion, with bone screw apertures angled to enhance shear loading and secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If rectangular or square implants are used, then manufacturing is simple and standardized, but they fail to conform to the natural anatomy of the disc space and may protrude into the spinal canal
Solution Approach 1:
The implant transitions from a symmetric rectangular/square shape to an asymmetric rhomboid shape with specific angular configurations (e.g., 60-120 degree angles) that match the natural disc space geometry. This asymmetric design allows the implant to conform to the triangular or trapezoidal disc space while maintaining manufacturability through standardized angular features.
Solution Approach 2:
The implant geometry is defined by specific parameter ranges: angles between 60-120 degrees, height-to-width ratios between 0.5-1.5, and chamfer dimensions of 0.5-5mm. These parameter changes from conventional rectangular designs enable anatomical conformity while controlling manufacturing complexity through quantifiable design specifications.
2Strength
If bone screw apertures are oriented perpendicular to endplates, then shear loading is enhanced and fixation is improved, but the implant geometry becomes more complex
Solution Approach 1:
The rhomboid implant creates asymmetric aperture orientations where superior and inferior bone screw holes are angled differently relative to the implant body. This asymmetry enables each aperture to be oriented optimally perpendicular to its respective endplate while maintaining a unified implant structure, thereby improving fixation strength without excessive complexity.
3Area of stationary object
If rhomboid shaped implants are used, then endplate coverage is maximized and anatomy conformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The rhomboid geometry is controlled through specific parameter ranges: angles of 60-120 degrees, height-to-width ratios of 0.5-1.5, and defined chamfer dimensions of 0.5-5mm. These parameter specifications enable manufacturers to achieve the required precision through standardized machining processes while maximizing endplate coverage area through optimized dimensional proportions.
Solution Approach 2:
Chamfered edges with radii of 0.5-5mm are incorporated at the superior and inferior corners of the implant. These curved transitions reduce stress concentrations and facilitate precise seating on the endplates, thereby improving manufacturing precision requirements while enhancing anatomical conformity and endplate coverage.
Data Source
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AI summary
A rhomboid shaped spinal implant may include a proximal surface that extends from a first lower end to a first upper end thereof a first distance, and a distal surface that extends from a second lower end to a second upper end thereof a second distance. The implant may include a superior surface that extends from the first upper end of the proximal surface to the second upper end of the distal surface a third distance, and an inferior surface that extends from the first lower end of the proximal surface to the second lower end of the distal surface a fourth distance. In various embodiments, the first distance is greater than the second distance, and the third distance is less than the fourth distance. In some embodiments, at least one bone screw aperture defines a trajectory extending in a direction substantially perpendicular to the superior and/or inferior surface.