Dual-Layer Braided Spinal Tether for Growth Modulation
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Solution Overview
Problem
Current surgical methods for correcting spinal disorders, such as scoliosis and kyphosis, often rely on rigid implants that inhibit natural spinal movement and may not effectively address growth modulation, leading to incomplete relief of symptoms and potential progression of deformities.
Innovation Solution
A spinal construct featuring a flexible tether with a dual-layered braid design, where the inner braid defines a smaller angle and the outer braid defines a larger angle, providing high strength and stiffness in the loading direction while allowing soft, low-friction flexibility, is used to achieve vertebral compression and growth modulation without inhibiting natural spinal movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid implants are used for spinal correction, then spinal stability is improved, but natural spinal movement is inhibited
Solution Approach 1:
The patent employs flexible tethers instead of rigid implants to correct spinal deformities. These tethers are designed with appropriate flexibility to allow natural spinal movement while providing the necessary corrective force and stability. The flexible nature of the tethers enables them to conform to the dynamic anatomy of the spine during movement, resolving the contradiction between stability and adaptability.
Solution Approach 2:
The patent utilizes adjustable parameters of the tether system, including tether stiffness, length, and attachment points, to optimize both spinal stability and preservation of natural movement. By carefully selecting and adjusting these parameters, the system achieves the desired balance between providing corrective stability and allowing physiological spinal motion.
2Shape
If rigid fixation is applied, then deformity correction is achieved, but growth modulation capability is reduced
Solution Approach 1:
The patent employs dynamic tether systems that can adapt to growing spines in pediatric patients. The tethers are designed with flexible properties that allow them to accommodate ongoing spinal growth while maintaining corrective positioning. This dynamic characteristic enables the system to provide both deformity correction and growth modulation, as the tethers can be adjusted or replaced as the patient grows.
Solution Approach 2:
The flexible tether construction allows for growth modulation by permitting controlled movement and adaptation as the spine grows. Unlike rigid fixation that completely restricts motion, the flexible tethers allow physiological movement patterns that support healthy spinal development while maintaining corrective alignment.
3Strength
If high strength implants are used, then load bearing capacity is improved, but flexibility for natural movement is reduced
Solution Approach 1:
The patent utilizes flexible tethers with engineered mechanical properties that provide adequate load-bearing capacity while maintaining the flexibility needed for natural spinal movement. The tether materials and construction are designed to distribute loads appropriately across the spinal segment, providing sufficient strength without the rigidity that would inhibit physiological motion.
Solution Approach 2:
The patent employs composite tether constructions combining materials with complementary properties. The inner braid provides high strength for load bearing, while the outer braid contributes flexibility and low friction characteristics. This composite structure resolves the contradiction between strength and flexibility by integrating materials that excel in different mechanical properties.
4Reliability
If friction-resistant materials are used, then tether durability is improved, but controlled movement capability is reduced
Solution Approach 1:
The patent employs a composite braid structure where the inner braid uses high-friction materials for durability and secure anchoring, while the outer braid uses low-friction materials that enable controlled movement and sliding. This layered composite construction resolves the contradiction by assigning different friction characteristics to different functional zones of the tether system.
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 flexible tether system effectively modulates vertebral growth, reduces deformity progression, and maintains spinal alignment, offering a fusionless treatment option for young patients with idiopathic scoliosis by allowing controlled extension and resisting excessive elongation under load.
Implementation Method 1
The second layer includes a plurality of interlaced strands that define a second angle. The first angle is smaller than the second angle.
Implementation Method 2
providing high strength and stiffness in the loading direction while allowing soft, low-friction flexibility
Implementation Method 3
achieve vertebral compression and growth modulation without inhibiting natural spinal movement
Data Source
AI summary
A spinal construct comprises a member extending between a first end and a second end and includes a first layer and a second layer. The first layer includes a plurality of interlaced strands that define a first angle. The second layer includes a plurality of interlaced strands that define a second angle. The first angle is smaller than the second angle. Systems, implants, surgical instruments and methods are disclosed.