Bone Fastener Assembly Pivoting Seat Angular Adjustment
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Solution Overview
Problem
Current polyaxial screw systems for stabilizing vertebrae offer limited angular adjustment, which can restrict the ability to align fasteners at various angles relative to the bone and stabilizing constructs, potentially compromising the effectiveness of spinal stabilization procedures.
Innovation Solution
A bone fastener assembly that includes a connecting member, a fastener seat, and a bone fastener, allowing for pivoting and swiveling movements to achieve greater angular adjustment, with mechanisms such as notches and spherical surfaces enabling the fastener to pivot in one direction and swivel about a longitudinal axis, enhancing the alignment and stability of the bone and stabilizing construct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polyaxial screw systems are used for stabilizing vertebrae, then the ability to align fasteners at various angles is improved, but the angular adjustment range is limited
Solution Approach 1:
The fastener assembly is divided into separate functional components: a connecting member with a longitudinal axis, a fastener seat with a transverse axis that can pivot relative to the connecting member, and a fastener that can swivel within the fastener seat. This segmentation allows each component to provide independent degrees of freedom, achieving polyaxial adjustment while maintaining structural clarity and avoiding excessive complexity.
2Adaptability or versatility
If the fastener seat is constrained to a fixed position, then the assembly structure is simpler, but the angular adjustment capability is reduced
Solution Approach 1:
The fastener seat is designed with dynamic characteristics, allowing it to pivot relative to the connecting member about an axis transverse to the longitudinal axis. This dynamic capability enables the fastener seat to assume different angular positions, providing enhanced adaptability for aligning fasteners at various angles relative to the bone and stabilizing construct, while the pivot mechanism remains mechanically simple.
Data Source
AI summary
A bone fastener assembly for connecting a bone to a stabilizing construct includes a connecting member, a fastener seat, and a bone fastener. The connecting member includes a connecting member axis, a first opening, a second opening, and a first spherical surface. The connecting member axis extends from a proximal end to a distal end. The first opening is adjacent the proximal end. The second opening is adjacent the distal end. The fastener seat includes a first end, a second end, a passageway, and a second spherical surface. The passageway extends from the first end to the second end along a seat axis. The second spherical surface is configured to slidably engage the first spherical surface. The bone fastener includes a shank and a head. The shank extends though the passageway. The head engages a head-mating surface of the fastener seat.