Articulating Expandable Intervertebral Spacer Height Adjustment
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Solution Overview
Problem
The spinal column often requires additional support due to weaknesses caused by degenerative diseases, tumors, fractures, and dislocations, and existing solutions fail to provide effective adjustable support between adjacent vertebrae to maintain stability and promote fusion.
Innovation Solution
An adjustable intervertebral spacer with a frame, endplates, a link, and an actuating screw that allows for expansion by moving the endplates relative to the frame, enabling increased height and secure bone separation, facilitating fusion and stabilization of adjacent vertebrae.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed-height spacer is used to separate vertebrae, then the insertion procedure is simple, but the device cannot be adjusted to restore optimal disc height or accommodate varying patient anatomy
Solution Approach 1:
The spacer transitions from a fixed structure to a dynamic, adjustable structure through the incorporation of a carriage mechanism that can be repositioned along the longitudinal axis of the frame. The carriage is movable relative to the frame and can be locked at different positions, allowing the spacer height to be adjusted post-insertion to accommodate varying disc height requirements and patient anatomy.
Solution Approach 2:
The spacer is divided into separable components including a frame, a movable carriage, and an actuating mechanism. This segmentation allows the carriage to be independently positioned and adjusted relative to the frame, enabling height adjustment without requiring replacement of the entire spacer device.
2Strength
If a tall spacer is used to restore disc height, then the stabilization effect is improved, but the insertion through minimally invasive approaches becomes difficult
Solution Approach 1:
The spacer is designed with a collapsible or compressible configuration that allows it to be reduced to a smaller size for insertion through minimally invasive approaches. After insertion, the spacer can be expanded or adjusted to its full height to provide the necessary stabilization and disc height restoration.
Solution Approach 2:
The carriage and actuating mechanism are positioned within the frame structure in a nested arrangement, allowing the entire assembly to have a compact profile during insertion while maintaining the capability to expand to full functional height after implantation.
3Length of stationary object
If the spacer height is increased to accommodate disc height loss, then the disc space restoration is improved, but the risk of neural element compression increases
Solution Approach 1:
The adjustable height mechanism allows the spacer to be precisely positioned at the optimal height that restores disc space without excessive elevation that could compress neural elements. The carriage can be fine-tuned to achieve the exact height needed, and the device can be adjusted post-insertion if neural compression is detected.
Solution Approach 2:
The design allows for post-insertion adjustment and verification of spacer height, enabling the surgeon to monitor for neural element compression and adjust the spacer height accordingly. The movable carriage can be repositioned based on intraoperative feedback regarding neural element status.
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 spacer provides adjustable support and fusion between vertebrae, allowing for minimally invasive insertion and expansion, reducing tissue damage and enabling effective stabilization and restoration of disc height, while allowing for repositioning and re-expansion if necessary.
Implementation Method 1
an actuating screw moveable with respect to the frame and pivotally connected to the link to cause movement of the link when the actuating screw is moved with respect to the frame
Implementation Method 2
an actuating screw moveable with respect to the frame and pivotally connected to the link
Implementation Method 3
a first endplate configured to engage a first bone of the joint, and having at least one ramped surface mateable with the at least one ramped surface of the frame, whereby when the first endplate is moved relative to the frame in a direction along the frame longitudinal axis, the first endplate is moved in a direction away from the frame to increase a height of the spacer
Data Source
AI summary
A spacer for separating bones of a joint, the spacer includes a frame having a longitudinal axis, and ramped surfaces. An endplate configured to engage a bone of the joint has ramped surfaces mateable with the ramped surfaces of the frame. When the endplate is moved relative to the frame in a direction along the longitudinal axis of the frame, the endplate is moved in a direction away from the frame to increase the height of the spacer. A second endplate configured to engage a second bone of the joint can be similarly configured.