Expandable Lordosis Spacer for Disc Height and Spinal Alignment
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Solution Overview
Problem
Conventional intervertebral fusion devices face challenges in fitting properly with adjacent vertebral bodies due to differences in height caused by distraction, often requiring excessive bone removal and prolonged healing times, and fail to account for lordosis curvature.
Innovation Solution
An expandable fusion device with endplates and ramps that can transition between collapsed and expanded configurations, allowing for insertion at minimal distraction height and maintaining normal disc spacing while accommodating lordosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional fusion devices are dimensioned larger in height than the initial distraction height to maintain disc spacing, then disc spacing is restored, but installation becomes difficult
Solution Approach 1:
The fusion device incorporates an expandable cage structure that can be inserted in a compressed state and then expanded within the intervertebral space. This dynamic transformation allows the device to be installed at a smaller height than the final disc spacing requires, then expanded to achieve the proper spacing maintenance function.
Solution Approach 2:
The expandable cage is designed with nested components that allow it to be collapsed into a compact form for insertion through the surgical approach, then deployed to its full size. The cage structure contains movable elements that nest within each other during compression and expand outward during deployment.
2Ease of manufacture
If traditional fusion devices are used without accounting for lordosis curvature, then device installation is simpler, but proper alignment with adjacent vertebral bodies is not achieved
Solution Approach 1:
The endplates of the fusion device are designed with curved surfaces that match the natural lordotic curvature of the spine. This curvature allows the device to conform to the anatomical shape of the vertebral bodies, achieving proper alignment without requiring complex bone removal procedures.
Solution Approach 2:
The device incorporates different geometric features at different locations: the endplates have curved surfaces for matching lordosis, while the cage structure provides expansion capability. This localized differentiation of geometric properties allows the device to simultaneously achieve anatomical conformity and functional performance.
3Manufacturing precision
If bone is removed from vertebral bodies to ensure proper fit of traditional devices, then device fit is improved, but procedure time and healing time increase
Solution Approach 1:
The expandable cage structure changes its dimensional parameters after insertion, transforming from a compressed insertion state to an expanded functional state. This parameter change allows the device to achieve proper fit and alignment without requiring pre-operative bone removal, thereby reducing surgical time and promoting faster healing.
Data Source
AI summary
An expandable fusion device may include a first endplate and a second endplate. The expandable fusion device may also include first and second ramps configured to mate with both the first and second endplates. An inserter instrument includes an outer shaft having a bore extending longitudinally therethrough and an inner shaft extending through the bore in the outer shaft. The outer shaft is configured to engage the first or second opening in the second ramp, and the inner shaft is configured to engage the corresponding first or second opening in the first ramp to control implant height and/or lordotic angle.