Spinal Fixation Element With Resilient Biasing Member
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Solution Overview
Problem
Current spinal correction systems fail to maintain a constant load on flexible longitudinal elements over time, leading to instability and potential loosening due to deformation or growth, which is a challenge in treating spinal disorders such as scoliosis and kyphosis.
Innovation Solution
A spinal correction system incorporating a deformable compliant material, such as a spring, within a fixation element and connector to maintain a constant load on a flexible tether, which includes a washer to disperse the load and a resilient biasing member to adapt to changes such as patient growth and system deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid fixation element is used to secure the flexible longitudinal element, then initial stability is achieved, but the system becomes unstable over time due to deformation and growth
Solution Approach 1:
The fixation element incorporates a resilient biasing member (spring) that transforms the rigid structure into a dynamic system capable of adapting to changes in the flexible longitudinal element. The spring allows the fixation element to maintain constant engagement force while accommodating growth and deformation, resolving the contradiction between initial stability and long-term adaptability.
Solution Approach 2:
The system changes the physical state of the fixation element by incorporating a compliant material or spring mechanism that can alter its engagement parameters. This allows the fixation element to maintain constant load on the flexible longitudinal element despite changes in length or shape, achieving both stability and adaptability through parameter adjustment.
2Force
If a constant load is applied to the flexible longitudinal element, then correction effectiveness is improved, but deformation and loosening occur over time
Solution Approach 1:
The resilient biasing member acts as a feedback mechanism that continuously adjusts the engagement force between the fixation element and the flexible longitudinal element. When deformation or growth occurs, the spring automatically compensates by maintaining constant load, ensuring the correction force is sustained over the entire duration of treatment without loosening.
Solution Approach 2:
The compliant material or spring in the fixation element provides beforehand cushioning by anticipating and accommodating future deformation of the flexible longitudinal element. This pre-built compliance mechanism prevents loosening by maintaining constant engagement force throughout the expected duration of treatment.
3Strength
If a rigid connector is used to attach the flexible longitudinal element, then structural strength is improved, but the system cannot accommodate patient growth
Solution Approach 1:
The connector incorporates a resilient biasing member that transforms the rigid attachment into a dynamic joint. This allows the connector to maintain strong structural engagement while accommodating changes in the flexible longitudinal element's length, enabling both strength and adaptability to patient growth.
Solution Approach 2:
The connector combines rigid structural components with compliant materials or spring mechanisms to create a composite structure. This hybrid design provides the strength needed for secure attachment while incorporating the flexibility required to accommodate growth and deformation over time.
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 maintains a consistent holding force on the tether, preventing loosening and instability, even with changes in the patient's anatomy or system components, thereby providing long-term stability and correction for spinal deformities.
Implementation Method 1
a resilient biasing member, such as, but not limited to, a spring to maintain the constant load
Data Source
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AI summary
A spinal correction system comprises a flexible longitudinal element extending between a first end and a second end. At least one fixation element includes a first portion and a second portion. The first portion includes an inner surface that defines a cavity such that the longitudinal element is disposable therein. The second portion is configured for penetrating tissue. A coupling member is engageable with the first portion of the at least one fixation element and the longitudinal element to connect the longitudinal element with the at least one fixation element. The coupling member includes a penetrating element configured to extend through the longitudinal element. A flexible member is disposed between the longitudinal element and the inner surface of the first portion of the at least one fixation element. Methods of use are disclosed.