Intervertebral Implant Three-Point Contact Design
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Solution Overview
Problem
Conventional spinal fusion procedures for lumbar degenerative disc disease have high complication rates and do not preserve spinal mobility, while existing disc replacement implants often require multiple points of contact with the vertebrae, making them larger and more difficult to insert.
Innovation Solution
An intervertebral implant with an outer surface that engages the vertebrae at only three distinct points, featuring a convex or kidney-shaped footprint with two lateral-anterior and one posterior point of contact, allowing for a smaller size and easier insertion, and including a movable insert and keel protrusions for anchoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing disc replacement implants are designed with multiple points of contact with vertebrae, then stability and anchoring are improved, but implant size increases and insertion difficulty increases
Solution Approach 1:
The outer surface of the implant is designed with non-uniform contact characteristics, concentrating engagement at three specific locations (anterior, posterior, and lateral aspects) rather than distributing contact across the entire surface. This localized contact approach provides sufficient anchoring stability while reducing overall implant footprint and facilitating easier insertion through the intervertebral space.
2Ease of operation
If implant footprint is reduced for easier insertion, then insertion size is reduced, but contact area with vertebrae decreases
Solution Approach 1:
The outer surface incorporates curved and convex geometries that concentrate contact forces at three discrete points rather than requiring a large flat contact area. The keel protrusions and surface contours are shaped to engage the vertebral body at specific locations, providing reliable anchoring through geometric interlocking rather than through large surface area contact.
3Object-affected harmful factors
If conventional spinal fusion procedures are used, then pain generation is removed, but spinal mobility is lost and complication rates increase
Solution Approach 1:
The implant incorporates a movable insert that allows dynamic motion between the upper and lower vertebral bodies, enabling the implant to accommodate physiological spinal movements while providing pain relief. This dynamic capability distinguishes the device from static fusion constructs and preserves spinal adaptability.
Data Source
AI summary
A method of implanting an intervertebral implant or component thereof, in which each component is selected to have an inner surface and an outer surface which engages an adjacent vertebra and presents only three distinct points of contact with a cortical rim of the vertebra. The outer surface is selected to have a footprint which is sized to be within that of the cortical rim. In disclosed embodiments, the footprint can be convexo-concave shaped or kidney shaped. The intervertebral implant can be provided with upper and lower (or first and second) components which engage adjacent first and second vertebrae and which move relative to one another. The implant has both the first and second outer surfaces sized to present a respective footprint sufficient for two lateral-anterior and one posterior points of contact with an adjacent cortical rim of the respective first and second vertebra.