Adjustable Intervertebral Implant Height Restoration
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Solution Overview
Problem
Degenerative disc disease leads to loss of disc height, causing facet and nerve impingement, and existing intervertebral implants do not effectively restore the natural height between vertebral bodies.
Innovation Solution
An adjustable intervertebral implant with a first and second member and an expansion ring, where the expansion ring's threading engages with the outer surface of the first member, allowing rotation to axially move the members, enabling adjustable height restoration between vertebral bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-height intervertebral implant is used, then the implant structure is simple, but the disc height loss and facet/nerve impingement cannot be effectively restored
Solution Approach 1:
The implant transitions from a fixed structure to a dynamically adjustable structure through the expansion ring mechanism. The ring can be rotated to expand or contract the implant height, allowing the device to adapt to the specific disc space requirements while maintaining structural integrity through threaded engagement between the ring and implant body.
Solution Approach 2:
The implant is divided into separable components including the implant body, expansion ring, and locking mechanism. This segmentation allows for adjustable height configuration by rotating the expansion ring to expand or contract the implant, then locking at the desired height to restore disc space and prevent facet/nerve impingement.
2Adaptability or versatility
If a customizable height implant is designed, then the disc height restoration is improved, but the ease of operation during surgery is reduced
Solution Approach 1:
The expansion ring incorporates integrated threading that directly engages with the implant body, allowing the surgeon to adjust the implant height through simple rotational motion of the ring itself. The locking mechanism is self-contained within the ring structure, eliminating the need for separate adjustment tools or complex multi-step procedures during surgery.
3Adaptability or versatility
If the first member is made smaller to fit within the second member, then the adjustability is improved, but the structural strength is reduced
Solution Approach 1:
The first member is nested within the second member, with the expansion ring engaging threaded portions on both members. This nested configuration allows the smaller first member to be received within the larger second member while maintaining structural strength through the interlocking threaded engagement that distributes mechanical loads across both components during height adjustment and loading.
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 adjustable implant effectively restores the natural height between vertebral bodies, reducing facet and nerve impingement by allowing customizable expansion and contraction, facilitating bone growth and fusion.
Implementation Method 1
the ring includes one or more threads for engaging one or more threads formed on the outer surface of the first member so that rotation of the ring causes the first member to axially move or translate with respect to the second member
Data Source
AI summary
An adjustable intervertebral implant for implantation into a patient's spine in-between first and second adjacent or neighboring vertebrae. The implant may include one or more of the following features: (i) inner and outer members coupled by a radiographically imagable expansion ring, (ii) detachable endplates coupled to the implant via a polygonal press-fit coupling interface that accommodate a range of lordotic endplates to be applied to the implant using any surgical approach, (iii) an interference pre-loaded set screw for selectively locking the height of the construct, (iv) a radiographically imagable marker for determining the expansion of the implant, and (v) an asymmetric thread coupling between the expansion ring and the inner member.