Adjustable Bone Screw Angular Locking Mechanism
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Solution Overview
Problem
Current spinal implant systems for treating disorders such as scoliosis and degenerative disc disease lack the ability to adjust angles effectively, leading to inadequate correction and stability during surgical procedures.
Innovation Solution
A spinal implant system featuring an adjustable bone screw with a receiver and shaft configuration that allows for multi-axial or uniaxial adjustment, enabling precise angular locking of spinal rods and screws to correct spinal deformities, including scoliosis and kyphosis, by using a setscrew mechanism and a tulip head assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional fixed-angle bone fasteners are used, then the device structure is simple, but the ability to correct spinal deformities and provide stable alignment is insufficient
Solution Approach 1:
The bone fastener incorporates a dynamic angle adjustment mechanism that allows the shaft to be positioned at multiple angles relative to the receiver before being locked in place. The set screw mechanism enables the structure to transition from a flexible, adjustable state to a fixed, stable state, providing both adaptability during implantation and stability during healing.
Solution Approach 2:
The fastener is divided into distinct functional segments: the receiver portion that engages with the spinal rod, the shaft that penetrates the bone, and the set screw mechanism that enables angle adjustment and locking. This segmentation allows each component to perform its specific function independently while contributing to the overall angular adjustment capability.
2Manufacturing precision
If multi-axial adjustment mechanisms are added to enable precise angular locking, then deformity correction capability is improved, but the device complexity increases
Solution Approach 1:
The fastener design allows for changing the angular parameter of the shaft relative to the receiver through a controlled adjustment mechanism. The set screw enables precise adjustment of the angle by applying mechanical constraint, transforming the fastener from a fixed-angle component to an adjustable-angle component with improved manufacturing precision for spinal alignment.
3Adaptability or versatility
If an adjustable angle mechanism is implemented, then correction capability for spinal deformities is enhanced, but the ease of operation during surgery is reduced
Solution Approach 1:
The angle adjustment mechanism is designed to be operated before the final tightening and locking steps of the surgical procedure. The set screw is engaged and adjusted to the desired angle while the fastener is still accessible, allowing the surgeon to establish the correct angular alignment before committing the implant to its final fixed position, thereby maintaining ease of operation.
Data Source
AI summary
A bone fastener comprises a first member including an inner surface defining an implant cavity. A part is disposed with the first member and is non-rotatable relative to the inner surface. A second member is disposed at an angle relative to the first member and configured to penetrate tissue. The part axially translates relative to the inner surface and engages the second member to selectively adjust the angle. Implants, systems, constructs, instruments and methods are disclosed.