Expandable Intervertebral Spacer for In Situ Fit Adjustment
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Solution Overview
Problem
Existing expandable intervertebral spacers lack improvements for optimizing fit and reducing impaction during implantation, necessitating better designs for spinal stabilization.
Innovation Solution
The design of an expandable spacer comprising a main body, endplates, a driving member, pins, and an actuation member, allowing for controlled expansion in situ by transitioning between configurations through rotational movement of the actuation member, which forces the driving member to move linearly and separate the endplates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a static intervertebral spacer with fixed dimensions is used, then the device structure is simple, but the fit optimization is limited and trial-and-error selection is required
Solution Approach 1:
The spacer incorporates an expandable structure with multiple configurations that can be adjusted in situ. The expandable body transitions between compressed and expanded states, allowing the clinician to optimize the fit between vertebral bodies after implantation, thereby resolving the contradiction between adaptability and device complexity.
Solution Approach 2:
The spacer utilizes a nested configuration where the expandable body is contained within a delivery system in a compressed state, then expanded to its functional configuration after implantation. This nesting approach enables a complex expandable structure to be delivered through a simpler delivery mechanism, addressing both fit optimization and device complexity.
2Object-affected harmful factors
If a static spacer is used, then the device is easier to manufacture, but impaction of adjacent vertebral bodies occurs during insertion
Solution Approach 1:
The spacer is designed to be inserted in a compressed state and then expanded in situ to its functional size. This dynamic approach eliminates the need to force a fully-sized spacer into the intervertebral space, thereby preventing impaction of adjacent vertebral bodies during insertion while maintaining manufacturing feasibility.
Solution Approach 2:
The spacer is prepared in a pre-compressed configuration before insertion, allowing it to be delivered through the delivery system without impacting the vertebral bodies. The expansion to full size occurs after proper positioning, preventing harmful impaction forces during the insertion process.
3Manufacturing precision
If trial-and-error selection of spacer size is performed, then the appropriate fit can be identified, but the procedure time increases
Solution Approach 1:
The expandable spacer allows the clinician to implant a single spacer and then adjust its size in situ by controlling the expansion degree. This eliminates the need for multiple trial-and-error insertions of different sized spacers, thereby achieving precise fit while significantly reducing procedure time.
Solution Approach 2:
The spacer's key parameter (size/volume) can be changed dynamically after implantation through controlled expansion. This parameter adjustment capability allows precise fit optimization without requiring multiple surgical interventions or trial spacers, resolving the time-precision contradiction.
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
This design optimizes the fit of the spacer between vertebral bodies, reducing the need for trial-and-error selection and minimizing impaction during insertion, thereby enhancing spinal stabilization and nerve protection.
Implementation Method 1
The actuation member is configured to be inserted into the driving member to transition the expandable spacer from a first configuration to a second configuration. The plurality of pins has at least two pins, each pin includes a first end and a second end. The first end or the second end of each pin passes through and is received by one opening disposed on the main body, one opening disposed on the first endplate, one opening disposed on the second endplate, and one opening disposed on the driving member to assemble the main body, the first endplate, the second endplate, and the driving member together.
Data Source
AI summary
The description relates to an expandable intervertebral spacer configured to engage an intervertebral disk. An example expandable spacer includes a main body, a first endplate, a second endplate, a driving member, a plurality of pins, and an actuation member. The expandable spacer is configured to transition from a first configuration to a second configuration by various structures (e.g., steps, faceted surfaces, curved surfaces, multi-faceted portions) defined on the first endplate, the second endplate, and the driving member.