Dual-Screw Ramp Adjustment for Expandable Interbody Devices
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Solution Overview
Problem
Existing expandable interbody devices face limitations in expansion range, subsidence due to inadequate load-bearing surfaces, and instability during expansion, posing challenges in maintaining proper positioning within the intervertebral space.
Innovation Solution
The development of highly adjustable interbody devices that can selectively increase or decrease spacing and angle between endplates, featuring a moving mechanism to expand and contract, allowing for precise adjustment and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If expandable interbody devices are used to provide additional spacing capability, then the device can be introduced in a collapsed state and expanded to produce additional spacing, but the devices have limited ranges of expansion
Solution Approach 1:
The interbody device is divided into multiple expandable segments or cells that can be independently or collectively expanded. This segmentation allows the device to achieve a wider overall expansion range while maintaining manageable complexity in each individual segment, resolving the contradiction between expansion range and device complexity.
2Strength
If existing interbody devices are used, then they provide static spacing, but they have inadequately-sized load-bearing surfaces causing subsidence
Solution Approach 1:
The interbody device incorporates an expandable structure that transitions from a collapsed to an expanded state, dynamically increasing the load-bearing surface area. This dynamic expansion allows the device to provide adequate load-bearing capacity and prevent subsidence while being introduisable through a narrow surgical path in its collapsed state.
3Strength
If expandable devices are used to increase load-bearing surface area, then subsidence can be avoided, but the load-bearing surfaces move relative to one another during expansion causing instability
Solution Approach 1:
The device incorporates an inserter or actuator mechanism that serves as an intermediary to control and coordinate the expansion of load-bearing surfaces. This intermediary mechanism ensures that surfaces expand in a controlled manner while maintaining proper alignment and relative positioning, preventing instability during the expansion process.
4Ease of operation
If interbody devices are adjusted in situ, then positioning can be optimized, but anatomical features such as iliac crest and rib cage pose challenges to adjustment
Solution Approach 1:
The interbody device is designed to be pre-adjusted or pre-positioned before final implantation, allowing optimization of spacing and alignment while avoiding interference from anatomical structures like the iliac crest and rib cage. The expandable design enables preliminary configuration in a controlled environment, and the device can then be inserted through a surgical path that bypasses anatomical obstacles.
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 solution provides enhanced stability and adjustability, minimizing subsidence and ensuring accurate positioning, thereby improving surgical outcomes by addressing the limitations of existing devices.
Implementation Method 1
a first support wedge that supports the first plate and defines a first ramp and a second support wedge that supports the second plate and defines second and third ramps. The expansion assembly includes an expansion wedge defining a fourth ramp. The first, second, third, and fourth ramps are each inclined with respect to a second direction
Implementation Method 2
The first, second, third, and fourth ramps are each inclined with respect to a second direction that is substantially perpendicular to the first direction. At least one of the first and second support wedges is slidable along the respective supported first or second plate
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The present disclosure provides for spinal implants deployable between a contracted position and an expanded position. The spinal implant may include a first endplate and a second endplate, each having a plurality of guide walls and inclined ramps. The spinal implant may further include a moving mechanism having first and second trolleys configured to act against the first and second plurality of ramps. The expansion mechanism may further include a first set screw and a second set screw opposite the first set screw. The moving mechanism may be configured to operably adjust a spacing between the first and second endplates upon simultaneous rotation of the first and second set screws along a rotation axis, and may also operably adjust an angle of inclination between the first and second endplates upon rotating the first set screw or second set screw along the rotation axis.