Expandable Interbody Device Wedge Mechanism ACDF Alignment
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Solution Overview
Problem
Conventional interbody implants for spinal procedures, particularly in the cervical region, have cumbersome mechanical mechanisms that are unsuitable for anterior cervical discectomy and fusion (ACDF) surgeries due to their large footprint, limiting their adjustability and suitability for precise spinal alignment.
Innovation Solution
An expandable interbody device with adjustable endplates that can be moved between contracted and expanded positions using a system of ramps and screws, allowing for precise distraction and lordosis adjustments, facilitated by a support block and wedges that enable parallel expansion and contraction of the implant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical mechanisms are used to separate endplates in interbody implants, then the implant can provide spinal stabilization, but the mechanism becomes cumbersome and requires a large footprint that is unsuitable for ACDF surgeries
Solution Approach 1:
The implant is divided into separate components including endplates, a body, and a distraction mechanism with movable wedge elements. This segmentation allows each component to be optimized independently, enabling a compact overall design while maintaining stabilization functionality through the coordinated interaction of segmented parts.
Solution Approach 2:
The distraction mechanism utilizes a wedge-shaped geometry where vertical movement of the wedge translates into horizontal separation of the endplates. This dimensional transformation allows the mechanism to achieve endplate distraction without requiring a large horizontal footprint, solving the space constraint problem in cervical spine applications.
2Reliability
If conventional interbody implants are used, then spinal stabilization is achieved, but the device lacks adjustability for precise spinal alignment in ACDF procedures
Solution Approach 1:
The implant incorporates a dynamic distraction mechanism with movable wedges that can be adjusted intraoperatively to change the spacing between endplates. This dynamic adjustability allows precise control over spinal alignment and lordosis angles, enabling the same implant design to adapt to various anatomical requirements in ACDF procedures while maintaining stabilization.
3Area of moving object
If a compact design is used for cervical spine implants, then suitability for ACDF procedures is improved, but the mechanism for expanding the implant becomes more complex
Solution Approach 1:
A threaded rod acts as an intermediary element that converts rotational motion into linear displacement of the movable wedges. This simple mechanical transmission mechanism enables compact expansion control without requiring complex actuation systems, maintaining ease of use while achieving a compact overall implant footprint suitable for cervical applications.
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 provides a highly adjustable and compact solution for spinal stabilization, suitable for ACDF procedures, allowing for precise alignment and expansion to accommodate bone growth promoting materials, enhancing surgical efficacy in treating spinal disorders.
Implementation Method 1
the proximal wedge may include first superior ramped surfaces and first inferior ramped surfaces, the proximal wedge may be coupled to the proximal set screw; and a distal wedge may include second superior ramped surfaces and second inferior ramped surfaces
Data Source
AI summary
An expandable implant movable between a contracted position and an expanded position, is disclosed. In various embodiments, the implant may be defined by a superior endplate and an inferior endplate having proximal ramps and distal ramps disposed on an interior surface thereof, respectively. In various embodiments, a proximal set screw and a distal set screw may be independently coupled to a proximal wedge and a distal wedge. Upon rotation of the proximal set screw, the proximal wedge may act against the proximal ramps of the superior and inferior endplates and cause the implant to expand at the proximal end. Upon rotation of the distal set screw, the distal wedge may act against the distal ramps of the superior and inferior endplates and cause the implant to expand at the distal end. In some embodiments, both the superior and distal set screws may be rotated simultaneously.