Spinal Correction System with Rigid Rod and Flexible Tethers
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Solution Overview
Problem
Current spinal correction technologies for musculoskeletal disorders, such as scoliosis and kyphosis, often fail to provide effective long-term correction and stability, especially in pediatric patients, as they either rely on fusion methods that limit growth or non-fusion methods that may not adequately address aggressive curvature.
Innovation Solution
A spinal correction system comprising a non-flexible spinal rod and flexible tethers that are attached to vertebral bodies using bone fasteners, allowing for apical fusion and adjacent level tethering, which provides rigid fixation while allowing for growth and adjustment on one side of the spine, thereby treating deformities like scoliosis and kyphosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fusion methods are used to correct spinal deformities, then stability and correction effectiveness are improved, but growth is limited
Solution Approach 1:
The spinal correction system divides the treatment approach into two segments: a rigid rod for apical fusion at the apex of the curve to provide stable correction, and flexible tethers for adjacent levels that allow growth. This segmentation allows simultaneous achievement of correction effectiveness and growth potential.
Solution Approach 2:
Different parts of the spinal construct have different mechanical properties: the apical portion has rigid fixation for stability, while the adjacent levels have flexible tethering that permits growth. This local differentiation of mechanical properties resolves the contradiction between correction effectiveness and growth preservation.
2Adaptability or versatility
If non-fusion methods are used to preserve growth, then adaptability is improved, but correction effectiveness and stability are insufficient
Solution Approach 1:
The system segments the spinal construct into rigid and flexible components, placing the rigid rod at the apex where correction is most needed and flexible tethers at adjacent levels where growth should be preserved, achieving both correction effectiveness and growth potential.
Solution Approach 2:
The spinal construct uses composite construction combining rigid rod material for apical fusion with flexible tether material for adjacent levels, creating a system that exhibits both rigid and flexible properties in appropriate locations to simultaneously achieve correction and preserve growth.
3Stability of the object's composition
If rigid fixation is applied to stabilize the spine, then stability is improved, but flexibility for growth is reduced
Solution Approach 1:
The spinal construct applies rigid fixation locally at the apical portion where stability is most critical for correction, while maintaining flexibility at adjacent levels through tethering, thereby achieving stability where needed without sacrificing overall growth potential.
Solution Approach 2:
The system transitions from static rigid fixation to a dynamic construct that combines rigid and flexible elements, allowing the spine to adapt and grow at non-apical levels while maintaining stability at the apex through the rigid rod.
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 system effectively corrects spinal deformities by applying a constant load to flexible elements, allowing for growth on one side while stabilizing the convex side, thus providing a durable and adjustable solution for musculoskeletal disorders, particularly in pediatric patients.
Implementation Method 1
A first flexible tether... A second flexible tether... allowing for growth on one side while stabilizing the convex side
Data Source
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AI summary
A spinal correction system comprises a first member configured for attachment to a first portion of vertebral tissue and a second member is configured for attachment to a second portion of the vertebral tissue spaced from the first portion. A third member has a non-flexible configuration relative to the first and second members and is configured for attachment to an apical portion of the vertebral tissue and along at least a portion of at least two vertebrae. The third member extends between a first end connected to the first member at a first transition configured for attachment to the first vertebral tissue and a second end connected to the second member at a second transition configured for attachment to the vertebral tissue. Methods of use are disclosed.