Oblique Capture Ring Bone Anchor for High-Angulation Strength
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Solution Overview
Problem
Existing pedicle screw systems with increased angulation housings suffer from reduced connection strength between the anchor component and rod-housing component.
Innovation Solution
A bone anchor with a rod-housing that allows adjustable angulation through a range of angles, facilitated by a capture ring with an oblique orientation and a base groove, maintaining connection strength while enabling increased angulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the housing component is designed to permit increased angulation, then the range of motion and adaptability are improved, but the connection strength between the anchor component and rod-housing component is reduced
Solution Approach 1:
The rod housing is divided into separate functional components: a base portion with a longitudinal axis, and a capture ring positioned at an angle oblique to the longitudinal axis. This segmentation allows the base to maintain structural strength while the angled capture ring enables increased angulation of the bone fastener relative to the rod housing, resolving the contradiction between connection strength and range of motion.
Solution Approach 2:
The capture ring is oriented at an angle oblique to the longitudinal axis of the rod housing, creating an asymmetric configuration. This asymmetric design allows the bone fastener to be contained and angled relative to the rod housing, providing increased adaptability in terms of angulation while maintaining connection strength through the asymmetric geometric relationship between components.
2Adaptability or versatility
If the bone fastener is contained within a capture ring at an oblique angle, then the angulation capability is improved, but the device complexity increases
Solution Approach 1:
The capture ring is positioned within the base of the rod housing, creating a nested configuration where the angled capture ring contains the bone fastener head. This nesting arrangement enables increased angulation capability while minimizing the overall increase in device complexity, as the components are integrated rather than added as separate external elements.
Data Source
AI summary
A bone anchor having a rod housing including a base that has an internal groove oriented at an angle oblique to the longitudinal axis of the base, a capture ring situated within the groove and oriented at an angle oblique to the longitudinal axis, and a bone fastener extending into the rod housing and including a fastener head situated within the base and having a surface that mates with the capture surface of the capture ring to maintain a connection between the bone fastener and the rod housing.