Transverse Link Spherical Ball Joint Spinal Load Distribution
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Solution Overview
Problem
Current transverse links in spinal deformity correction procedures impose undue loads on vertebrae due to limited three-dimensional movement and restricted rod fixation instrument movement, which can lead to undesirable manipulation and load distribution among fixation instruments.
Innovation Solution
A transverse link with rotatable spherical ball bearings and an automatic latching mechanism that allows for greater rotational and axial movement between engagement members, enabling secure alignment and distribution of load among two rod fixation instruments while allowing for three-dimensional pivoting and adjustable spatial positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current transverse links use fixed engagement members with limited movement, then the structure is simple and stable, but the rod fixation instruments are restricted in movement and impose undue load on vertebrae
Solution Approach 1:
The engagement members are designed with spherical ball bearings that enable dynamic movement in three dimensions. The ball bearings allow the engagement members to pivot and rotate freely, transforming the static structure into a dynamic one that can adapt to different positions and reduce mechanical stress on the vertebrae during manipulation.
Solution Approach 2:
The use of spherical ball bearings introduces curvature into the engagement mechanism. The spherical geometry allows for multi-directional rotation and pivoting, enabling the engagement members to move smoothly in three-dimensional space while maintaining a compact and manageable structure.
2Adaptability or versatility
If the base is configured to axially displace engagement members a predetermined distance, then the position of screw extenders is fixed, but the ability to adjust position in three dimensions is limited
Solution Approach 1:
The base is designed with a dynamic displacement mechanism that allows axial movement of the engagement members. The predetermined distance configuration can be adjusted, enabling the base to adapt to different spatial requirements while maintaining structural integrity and providing versatile positioning capability.
Solution Approach 2:
The base configuration enables movement not only in the axial direction but also in three-dimensional space through the spherical ball bearings. This adds another dimension of adjustability, allowing the engagement members to be positioned precisely in multiple directions while the base manages the complexity of coordinating these movements.
3Stress or pressure
If engagement members provide greater degree of movement in three dimensions, then load distribution among rod fixation instruments is improved, but the structural stability and precision of alignment may be compromised
Solution Approach 1:
The spherical ball bearings provide a curved contact surface that naturally distributes loads in multiple directions. The spherical geometry allows for precise alignment while accommodating movement, as the ball bearing maintains constant contact with the bearing supports regardless of the angle of approach, thereby reducing stress concentration and improving load distribution without compromising alignment precision.
Solution Approach 2:
The spherical ball bearing acts as an intermediary element between the engagement members and the bearing supports. It mediates the interaction by providing a smooth, distributed contact interface that allows movement while maintaining precise alignment and distributing loads effectively, thus resolving the contradiction between movement capability and alignment precision.
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 solution facilitates improved load distribution and increased movement capabilities, reducing the risk of undue stress on vertebrae during spinal alignment and fixation, thereby enhancing the precision and safety of spinal deformity correction procedures.
Implementation Method 1
The distal end of each stem of respective engagement members includes a spherical ball bearing. The receiving portion includes a pair of bearing supports configured to rotatably hold the spherical ball bearing.
Implementation Method 2
The chamfered edge of the spherical ball bearing increases the rotational movement of the spherical ball bearing about the axis orthogonal to the shaft relative to spherical ball bearings without the chamfered edge.
Implementation Method 3
One of the apertures is threaded. A knob having a threaded shaft is passed through the apertures of the bearing supports and the bore hole of the spherical ball bearing.
Implementation Method 4
The automatic latching mechanism is configured to urge a blocking member against the stem so as to fix the distance between the pair of engagement members.
Data Source
AI summary
A transverse link with a pair of opposing engagement members having a spherical ball bearing configured to fix a respective screw extender with respect to each other is provided. The spherical bearing is configured to allow the engagement member to rotate in three dimension so as to accommodate the position of a pair of respective screw extenders. The transverse link includes an automatic latching mechanism configured to fixed the spatial distance between the ends of the rod fixation instruments with respect to each other.