Expandable Spinal Interbody Devices for Minimally Invasive Surgery
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Solution Overview
Problem
Current spinal interbody and intravertebral devices are static in size, making them unsuitable for microsurgery and lacking in strength, reliability, and simplicity, which limits their effectiveness in spinal procedures.
Innovation Solution
Development of expandable spinal interbody and intravertebral devices that can dynamically change their radial profile from a collapsed to an expanded state through axial compression, allowing for controlled expansion and retraction, and are designed to provide micro-motion and act as an artificial disk or fusion device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If static sized spinal devices are used to properly bridge the gap between adjacent vertebrae, then the device provides structural support, but the device size becomes too large for microsurgery and arthroscopic surgery
Solution Approach 1:
The spinal device incorporates an expandable structure that transitions from a compressed delivery configuration to an expanded deployed configuration. The device includes expandable cage portions with radial struts that can be actuated to increase the overall device size after implantation, allowing initial small size for minimally invasive insertion followed by expansion to provide adequate structural support
Solution Approach 2:
The device employs a nested configuration where the expandable cage portions and radial struts are contained within a delivery system in a compressed state. Once implanted, the device expands outward from this nested configuration to achieve its functional size, effectively placing the functional structure inside the delivery mechanism during insertion
2Device complexity
If static sized spinal devices are used, then the device structure is simple, but the device lacks adaptability to accommodate individual patient needs and cannot allow surgeon control over expansion
Solution Approach 1:
The device includes actuation mechanisms such as threaded rods, balloons, or shape memory alloys that allow the surgeon to control the expansion process dynamically. The expansion can be adjusted to achieve the desired spacing between vertebrae for individual patient needs, transforming a static structure into an adaptable one through controlled mechanical action
Solution Approach 2:
The device allows change in geometric parameters (size, shape, spacing) after implantation through the expansion mechanism. The radial struts can be extended to specific lengths and the cage portions can be expanded to specific diameters, enabling customization of device parameters to match patient-specific anatomical requirements
3Ease of operation
If expandable spinal devices are used to reduce size for minimally invasive surgery, then the device can be easily inserted, but the device lacks strength, reliability and simplicity of design
Solution Approach 1:
The device is divided into multiple segments including end plates, radial struts, and cage portions that can be independently optimized for their functions. The segmentation allows each component to contribute to overall strength while the modular design enables compact folding for insertion. The segmented structure with interconnected struts provides structural integrity when expanded
Solution Approach 2:
The device employs composite material construction combining materials with high strength-to-weight ratios such as titanium alloys, cobalt-chromium alloys, or fiber-reinforced polymers. These composite materials provide the necessary mechanical strength and reliability for load-bearing spinal support while allowing the device to maintain a compact form factor for minimally invasive insertion
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 expandable devices enable minimally invasive implantation, customizable expansion, enhanced strength, and reliability, allowing for improved spinal stabilization and bone growth promotion while accommodating individual patient needs.
Implementation Method 1
The interbody device is expandable from a first radial profile into a second radial profile through axial compression of segments of the vertebral interbody device
Implementation Method 2
Each segment includes a central plate or body to which are pivotally attached plate or leaf structures. Pivoting of the structures provides a collapsed or unexpanded position of the first circumference and an open or expanded position of the second circumference
Data Source
AI summary
A device for insertion into a spinal (intervertebral or intravertebral) space is expandable from a first circumference to a second circumference through axial compression of segments of the device, particularly once the device has been properly situated within a vertebral space. The interbody/intravertebral body device is characterized by a plurality of axially stacked, individual segments that are provided on a central insertion and deployment rod. Each segment includes a central plate or body to which are pivotally attached plate or leaf structures. Pivoting of the structures provides a collapsed or unexpanded position of the first circumference and an open or expanded position of the second circumference.