Expandable Anterior Lumbar Implants for Height and Lordosis Control
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Solution Overview
Problem
Existing expandable implants for intervertebral fusion face challenges such as excessive impaction during insertion, visual obstruction, and imperfect matching with patient's lordosis due to discrete increments in lordotic angulation, necessitating devices that can provide distraction and achieve optimal height restoration and lordotic angulation independently.
Innovation Solution
Expandable intervertebral implants with an actuator assembly comprising moveable anterior and posterior actuators and a stationary posterior actuator, allowing independent control of anterior and posterior heights and lordotic angulation through a single type of thread profile, facilitating parallel and lordotic expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If existing expandable implants are used, then height restoration is achieved, but excessive impaction occurs during insertion
Solution Approach 1:
The implant is pre-compressed to a minimal height profile before insertion, allowing it to be introduced into the disc space without causing excessive impaction. The compression mechanism is activated prior to placement, enabling the implant to expand to the desired height only after insertion is complete.
Solution Approach 2:
The implant incorporates a dynamic compression and expansion mechanism that allows the height to be adjusted from a compressed insertion state to an expanded functional state. This dynamic transformation resolves the contradiction by enabling easy insertion in a compact form and subsequent expansion to achieve the required height restoration.
2Length of moving object
If existing expandable implants are used, then height restoration is achieved, but visual obstruction occurs
Solution Approach 1:
The implant is compressed to a minimal profile before insertion to minimize the visual footprint during the surgical approach. The compression is activated prior to placement, allowing the surgeon to access the disc space with minimal obstruction, and the implant is then expanded to the desired height after insertion.
3Length of moving object
If existing expandable implants are used, then height restoration is achieved, but lordotic angulation matching is imperfect due to discrete increments
Solution Approach 1:
The implant incorporates dynamic adjustment mechanisms that allow continuous or fine-step adjustment of lordotic angulation and height independently. This dynamic capability enables precise matching of the patient's specific lordotic requirements, overcoming the limitations of discrete incremental adjustments in fixed designs.
Solution Approach 2:
The implant is divided into separable components with independent adjustment capabilities, allowing the lordotic angulation and height to be optimized independently. This segmentation enables precise customization to match the patient's specific spinal anatomy and requirements.
4Manufacturing precision
If independent control of anterior and posterior heights is implemented, then lordotic angulation precision is improved, but device complexity increases
Solution Approach 1:
Multiple adjustment functions (anterior height, posterior height, lordotic angulation) are combined into a single integrated actuator assembly that controls all parameters through unified mechanisms. This merging reduces the number of separate components and simplifies the overall device while maintaining independent control capabilities.
Solution Approach 2:
The actuator assembly is designed as a multi-functional system that performs multiple adjustment operations through a single mechanism. This universal design allows one actuator system to control anterior height, posterior height, and lordotic angulation independently, reducing device complexity while maintaining precision.
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 implants provide precise restoration of spinal alignment and load distribution across vertebral endplates, matching patient-specific lordosis, and simplify expansion operations by using a unified direction for both lordotic and parallel expansion mechanisms.
Implementation Method 1
An actuator screw threads into an anterior actuator nut located in the moveable anterior actuator and a posterior actuator nut located in the stationary posterior actuator. The actuator screw threads through the moveable posterior actuator to translate the posterior actuator.
Data Source
AI summary
Expandable fusion devices, systems, and methods thereof. The expandable fusion implant may include upper and lower endplates configured to engage adjacent vertebrae and an actuator assembly for expanding the upper and lower endplates to independently control anterior and posterior heights of the implant. The actuator assembly may be operated in two modes: (1) to force the upper and lower endplates apart resulting in parallel expansion; and (2) to increase the anterior height of the implant resulting in an increase in lordotic angle.