Expandable Interbody Spacers for Precise Height and Lordotic Correction
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Solution Overview
Problem
Existing intervertebral implants with fixed dimensions often fail to provide adequate height restoration and support between vertebral bodies, requiring invasive procedures due to their larger pre-implantation size and limited ability to correct spinal curvature.
Innovation Solution
Expandable interbody spacers that can be inserted along one axis and expanded both horizontally and vertically, allowing for in situ expansion to fit the intervertebral space and provide lordotic correction, using a single axial force to pivotally link support members and end bodies for symmetrical or asymmetrical expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed dimension cages are used, then implantation is simpler, but height restoration precision and spinal support adequacy deteriorate
Solution Approach 1:
The cage transitions from a fixed static structure to a dynamic expandable structure. The cage body can be compressed to a smaller insertion profile and then expanded in situ to the desired final dimensions, allowing precise height restoration while maintaining simpler initial implantation.
Solution Approach 2:
The cage is designed with nested or telescoping components that allow the structure to be compressed into a smaller insertion profile. The cage body, end plates, and expansion mechanisms are arranged to fit within each other during insertion, then deployed to achieve the final expanded configuration for precise spinal support.
2Ease of operation
If fixed size cages are used, then device structure is simpler, but invasiveness of procedure increases due to larger pre-implantation size
Solution Approach 1:
The cage employs dynamic compression and expansion mechanisms that allow it to be delivered in a compressed low-profile state through less invasive approaches, then expanded to the required size at the implantation site. This reduces tissue disruption and surgical invasiveness.
Solution Approach 2:
The cage utilizes dimensional transformation by compressing the structure along one axis (reducing length/profile for insertion) and then expanding along perpendicular axes (restoring height and width for spinal support). This dimensional reconfiguration enables less invasive delivery while maintaining adequate final dimensions.
3Adaptability or versatility
If fixed dimension cages are used, then device design is simpler, but adaptability to different spinal curvatures and heights deteriorates
Solution Approach 1:
The cage incorporates dynamic adjustment capabilities that allow it to be expanded to different heights and angles depending on the specific spinal pathology and anatomical requirements. The expansion mechanism can achieve various final configurations from a single device design, providing adaptability to different spinal curvatures and intervertebral space dimensions.
Solution Approach 2:
The cage design includes asymmetric expansion capabilities with different expansion potentials in different directions. The structure can be expanded more in the vertical direction for height restoration or in the horizontal direction for lateral spacing, or combination thereof, allowing customization to match specific spinal anatomical variations and pathological conditions.
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 spacers offer precise height restoration and support, reducing the invasiveness of implantation procedures while allowing for customized lordotic correction, enhancing spinal stability and alignment.
Implementation Method 1
using a single axial force to pivotally link support members and end bodies for symmetrical or asymmetrical expansion
Data Source
AI summary
Interbody spacers are expandable horizontally and vertically by an application of axial force, and lockable in an expanded configuration. The spacers include support members interconnected to end bodies by pivotable link members. The spacers are introduced between vertebral bodies in a compressed configuration and expanded to fill the intervertebral space and provide support and selective lordotic correction. Graft material may be introduced into the expanded spacer. Provisional and/or supplementary locking means lock the spacers in the expanded configuration. Embodiments of the spacers include symmetrically and asymmetrically configured spacers. Methods of expansion include symmetric expansion or asymmetric expansion along each of two directions.