Flexible Spinal Tether for Gradual Scoliosis Correction
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Solution Overview
Problem
Current surgical methods for treating scoliosis, such as the Cotel-Dubousset system, are invasive, risky, and lead to complications like fatigue failure of implants due to the transfer of large spinal loads, and fail to utilize the viscoelastic properties of spinal structures for gradual correction.
Innovation Solution
A method and device that introduces tension between the pelvis and spine using flexible tethers or rods, allowing incremental correction over time, either through mechanical shortening or non-invasive means like magnetic fields, to correct or maintain spinal deformity without fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid metal rods are used to attach to the spine for correction, then immediate structural support is achieved, but fatigue failure occurs due to transfer of large spinal loads through the implant
Solution Approach 1:
The patent changes the mechanical parameters of the support structure by using flexible rods instead of rigid rods, allowing the implant to deform elastically under load rather than transferring all spinal loads rigidly, thereby reducing stress concentration and preventing fatigue failure
Solution Approach 2:
The patent introduces dynamic flexibility into the spinal implant system, where the flexible rods can adapt their stiffness and deformation characteristics based on applied loads, allowing the spine to move naturally while maintaining support, thus reducing rigid load transfer that causes implant failure
2Shape
If stiff metal rods are used for spinal correction, then immediate alignment is achieved, but viscoelastic properties of spinal structures are not utilized for gradual correction
Solution Approach 1:
The flexible rods enable the spinal implant to transition from a static rigid structure to a dynamic system that can gradually adapt to spinal deformities over time, utilizing the viscoelastic properties of spinal tissues to achieve progressive correction while maintaining immediate alignment
Solution Approach 2:
The patent enables periodic or progressive correction through the flexible rod system that allows incremental adjustments and gradual remodeling of spinal structures over time, rather than requiring immediate perfect alignment through rigid fixation
3Reliability
If extensive discectomies and spinous process removal are performed to induce bleeding for bone fusion, then fusion is achieved, but the surgery becomes arduous and invasive with excessive blood loss
Solution Approach 1:
The patent extracts or eliminates the need for extensive aggressive surgical maneuvers such as large discectomies and spinous process removals by using flexible rods that can achieve correction and stabilization with minimal tissue disruption, thereby reducing surgical invasiveness while maintaining fusion reliability
Solution Approach 2:
The flexible rod system allows the spine to utilize its own biological properties and natural healing processes to achieve fusion, rather than requiring aggressive surgical intervention to induce bleeding and stimulate bone growth, thereby reducing surgical complexity and invasiveness
4Productivity
If normal lordosis and kyphosis are not restored through surgery, then surgical procedure is simplified, but flat back syndrome occurs causing chronic pain
Solution Approach 1:
The flexible rod system dynamically adapts to restore natural spinal curvatures of lordosis and kyphosis by allowing progressive remodeling of spinal alignment over time, rather than requiring complex rigid manipulation during surgery, thereby achieving proper spinal geometry with simplified surgical procedures while preventing flat back syndrome
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
This approach reduces the risk of complications, allows for gradual and effective correction of spinal curvature, and leverages viscoelastic properties for sustained biomechanical stability, potentially reducing chronic pain and improving spinal alignment without the need for extensive bone grafting or invasive procedures.
Implementation Method 1
The mechanical properties of spinal structures such as the intervertebral discs, ligaments, nerves and muscles have a time-dependent relationship between force and displacement, a characteristic called viscoelasticity. Viscoelastic structures increase strain under the action of an applied constant stress (creep) and decrease internal stress under the action of an applied constant strain (stress-relaxation).
Implementation Method 2
In another embodiment, the means to shorten the device is a changing magnetic field.
Data Source
AI summary
The present invention generally relates to methods and devices for treatment of spinal deformity, and in particular to the utilization of at least one implant to either maintain the position of at least one vertebra of a patient to prevent increase in abnormal spinal curvature, to slow progression of abnormal curvature, or to impose at least one corrective displacement and/or rotation on at least one vertebra of a patient so as to incrementally correct abnormal spinal curvature.