Expandable Intervertebral Implant for Small-Incision Disc Height Restoration
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Solution Overview
Problem
Existing intervertebral implants struggle to restore the natural height and spacing of adjacent vertebrae while minimizing the size of the incision and avoiding contact with neural and vascular structures during implantation.
Innovation Solution
An expandable intervertebral implant with a linkage system comprising links that expand from a contracted to an expanded position, utilizing sloped engagement surfaces and inner cores to achieve vertical and lateral expansion, allowing insertion through a small incision and securing the implant in place with teeth and retainer members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the implant is inserted in a reduced size or configuration, then the incision size is minimized and contact with neural and vascular structures is limited, but the implant cannot restore the original height of the intervertebral disc
Solution Approach 1:
The implant transitions from a compressed insertion configuration to an expanded functional configuration after insertion into the intervertebral disc space. The expandable structure allows the implant to be inserted through a small incision in a reduced state, then expanded in situ to restore the original disc height and spacing between vertebrae.
Solution Approach 2:
The implant employs a nested structure where the inner core is disposed within the outer sleeve, allowing the entire implant to be compressed into a compact form for insertion through a small incision. After insertion, the implant expands from its nested state to achieve the required disc height restoration.
2Object-affected harmful factors
If the implant is inserted through a relatively narrow and small incision, then tissue disruption is minimized, but the implant cannot be properly sized and shaped to fill the physiological height between vertebral bodies
Solution Approach 1:
The implant is designed with dynamic expandability, allowing it to transition from a compact insertion state to a fully expanded functional state. This enables the implant to be inserted through a minimal incision while still achieving proper sizing and shaping to fill the physiological height between vertebral bodies after insertion.
Solution Approach 2:
The implant is divided into segmented components including an outer sleeve with first and second outer sleeve portions, and an inner core that can move relative to each other. This segmentation allows the implant to be compressed for insertion while maintaining the capability to expand to the correct size and shape for restoring disc height.
3Length of moving object
If the implant is made compact for insertion, then the incision size is reduced, but the mechanism for expansion increases device complexity
Solution Approach 1:
The implant incorporates a dynamic expansion mechanism where the inner core can move longitudinally within the outer sleeve to transform the implant from a compact insertion profile to an expanded functional profile. This dynamic capability allows minimal incision access while providing the necessary expansion function.
Solution Approach 2:
The expansion mechanism merges multiple functions into a single integrated structure: the outer sleeve provides both the insertion conduit and the expansion framework, while the inner core serves as both the expandable element and the structural support. This merging reduces overall device complexity compared to separate insertion and expansion components.
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 effectively restores the natural spacing and orientation of vertebrae, minimizing tissue disruption and facilitating fusion, while being compact for insertion and expandable in situ.
Implementation Method 1
Relative movement between the inner core and the second outer sleeve portion along the longitudinal direction causes the first engagement surface to ride along the second engagement surface, thereby causing the second outer sleeve portion to deflect away from the first outer sleeve portion in a direction substantially perpendicular to the longitudinal direction
Data Source
AI summary
An expandable intervertebral implant is provided for insertion into an intervertebral space defined by adjacent vertebrae. The expandable intervertebral implant includes a pair of outer sleeve portions and an inner core disposed between the outer sleeve portions. Movement of the inner core relative to the outer sleeve portions causes the outers sleeve portions to deflect away from each other, thereby engaging the expandable intervertebral implant with the vertebrae and adjusting the height of the intervertebral space.