Segmented Spinal Rod with Sagittal Rigidity and Coronal Flexibility
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Solution Overview
Problem
Current surgical methods for correcting spinal disorders, such as scoliosis and kyphosis, often fail to effectively stabilize the spine and prevent deformities as patients grow, leading to ongoing pain and mobility issues.
Innovation Solution
A spinal construct comprising a tether on the convex side of the spine to constrain growth and a semi-rigid, longitudinally configured rod on the concave side, which is flexible in the coronal plane to facilitate correction of lateral deformities while preventing lordosis in the sagittal plane, using a connector system that allows rotation and axial movement to maintain a selected sagittal curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid rod is used to stabilize the spine in the sagittal plane, then spinal stability and deformity prevention are improved, but flexibility in the coronal plane is reduced
Solution Approach 1:
The spinal correction system divides the rod into multiple segments with different mechanical properties. The rod comprises a first portion with higher rigidity in the sagittal plane for stability, and a second portion with greater flexibility in the coronal plane for adaptability. This segmentation allows each portion to perform its specialized function independently.
Solution Approach 2:
Different portions of the rod are designed with locally optimized properties: the first portion has structural characteristics that provide sagittal plane rigidity, while the second portion has characteristics that enable coronal plane flexibility. This local differentiation of mechanical properties resolves the contradiction between overall stability and localized flexibility.
2Adaptability or versatility
If a flexible rod is used to allow growth modulation, then adaptability to patient growth is improved, but spinal stability is reduced
Solution Approach 1:
The rod system transitions from a static, uniformly rigid structure to a dynamic system with controlled flexibility. The second portion of the rod is designed to be more flexible, allowing it to dynamically adapt to patient growth while the first portion maintains necessary stability. This dynamic characteristic enables growth modulation without compromising overall spinal stability.
3Stability of the object's composition
If a semi-rigid rod is used to prevent lordosis in the sagittal plane, then spinal alignment is improved, but correction of lateral deformities is reduced
Solution Approach 1:
The rod is segmented into functional portions: the first portion maintains sagittal alignment and prevents lordosis through its semi-rigid characteristics, while the second portion provides the flexibility needed for lateral deformity correction. This segmentation allows simultaneous achievement of sagittal stability and coronal plane adjustability.
Solution Approach 2:
The rod exhibits local quality differences where the first portion has optimized properties for sagittal plane control, and the second portion has optimized properties for coronal plane flexibility. This localized functional differentiation enables the rod to prevent lordosis while still allowing lateral deformity correction.
Data Source
AI summary
A spinal construct comprises a first member configured for attachment to a first portion of vertebral tissue that defines a longitudinal axis. A second member is configured for attachment to a second portion of the vertebral tissue such that the second portion is axially movable relative to the second member and sagittal movement of the second member relative to the second portion is resisted and/or prevented. Systems and methods are disclosed.