Externally Driven Expandable Interbody Implant for ACDF
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Solution Overview
Problem
Conventional mechanically operated interbody implants for the spine have a large footprint, making them unsuitable for anterior cervical discectomy and fusion (ACDF) procedures due to cumbersome mechanical mechanisms.
Innovation Solution
An externally driven expandable interbody implant with a superior and inferior endplate that can be moved and locked into various expanded configurations, featuring a threaded locking mechanism and surgical tools for precise expansion and locking, allowing for lateral bending and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional mechanical mechanisms are used to separate endplates, then the implant can achieve structural separation, but the footprint becomes too large for ACDF procedures
Solution Approach 1:
The expandable body is nested within the implant housing, allowing the mechanical structure to collapse into a compact form during insertion and then expand to its functional size once positioned. This nesting approach reduces the insertion footprint while maintaining the required structural separation capability.
Solution Approach 2:
The implant transitions from a static, fixed-size structure to a dynamic, expandable structure. The expandable body can change volume and configuration after insertion, allowing the implant to achieve its separation function only after being positioned, thereby resolving the contradiction between small insertion footprint and large functional footprint.
2Volume of moving object
If the implant is made compact for ACDF procedures, then it becomes suitable for cervical spine surgery, but the mechanical means to separate endplates becomes cumbersome
Solution Approach 1:
The complex mechanical separation mechanism is replaced with a simpler expansion system. Instead of using cumbersome mechanical means to separate endplates, the implant uses an expandable body that increases in volume to achieve separation, reducing operational complexity while maintaining compact dimensions.
Solution Approach 2:
The implant is divided into distinct functional segments: the housing, the expandable body, and the endplates. This segmentation allows each component to perform its specific function independently, with the expandable body providing the separation function without requiring complex mechanical linkages between components.
3Adaptability or versatility
If the implant allows lateral bending and adjustment, then it provides versatility for different spinal configurations, but the locking mechanism becomes more complex
Solution Approach 1:
The implant incorporates dynamic elements that allow lateral bending and angular adjustment after insertion. The expandable body can be positioned at different angles and configurations, providing versatility for various spinal alignment requirements without requiring a complex pre-configured locking mechanism.
Solution Approach 2:
The implant allows changes in geometric parameters such as expansion volume, angular orientation, and lateral position after insertion. These parameter changes enable the implant to adapt to different spinal configurations while using a relatively simple expansion-based mechanism rather than a complex multi-component locking system.
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 implant provides a compact and versatile solution for spinal realignment, suitable for ACDF procedures, with adjustable configurations for distraction and lordosis, enhancing surgical precision and stability.
Implementation Method 1
a threaded locking screw disposed in the threaded core and movable in the proximal-to-distal direction between the interior proximal wall and the medial support structure
Data Source
AI summary
An expandable implant having superior and inferior endplates is disclosed. The superior endplate includes a first inside surface having a crossbar extending in the widthwise direction. The inferior endplate includes a second inside surface having a medial support structure, a threaded core, and a receiving cavity. A threaded locking screw may be disposed in the threaded core, and a proximal saddle may be disposed in the receiving cavity. In various embodiments, in a locked position, a relative position of the inferior endplate with respect to the superior endplate is fixed, and the threaded locking screw directly contacts, pushes, applies a force against, and/or compresses, the proximal saddle, the proximal saddle directly contacts, pushes, applies a force against, and/or compresses the crossbar, the crossbar directly contacts, pushes, applies a force against, and/or compresses the distal saddle, and the distal saddle directly contacts and is engaged against the second interior distal wall.