Rotatable Bone Fastener Head for Spinal Alignment
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Solution Overview
Problem
Current spinal implant systems for treating spinal disorders often fail to adequately distribute stress across spinal elements, leading to suboptimal stabilization and potential complications during healing.
Innovation Solution
A spinal implant system featuring a bone fastener with a rotatable head and screw configuration that allows for 45 degrees of angulation and 180 degrees of rotation in the coronal plane, enabling precise alignment and fixation of vertebral rods, along with a S2-alar-iliac biased angle design for enhanced stability and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed-angle bone fastener is used, then the device structure is simple, but the alignment precision with vertebral rods is insufficient
Solution Approach 1:
The bone fastener incorporates a rotatable head that can be adjusted to different angles (e.g., 45 degrees) and rotated up to 180 degrees in the coronal plane. This dynamic adjustment capability allows the fastener to align precisely with vertebral rods while maintaining a relatively simple overall device structure, resolving the contradiction between alignment precision and device complexity.
2Reliability
If a fixed-angle bone fastener is used, then the device is easy to manufacture, but the stabilization effectiveness is insufficient
Solution Approach 1:
The adjustable and rotatable head design enables the bone fastener to achieve optimal alignment and stabilization effectiveness for each patient's specific anatomy, improving reliability. While this increases manufacturing complexity slightly, the modular design keeps the manufacturing process feasible and does not excessively complicate production.
3Adaptability or versatility
If a fixed-angle bone fastener is used, then the device complexity is low, but the adaptability to different spinal conditions is limited
Solution Approach 1:
The rotatable and adjustable head allows the single bone fastener design to adapt to various spinal conditions, anatomical variations, and surgical requirements. This dynamic capability provides versatility across different clinical scenarios without requiring multiple specialized fastener types, thereby managing device complexity while maximizing adaptability.
4Reliability
If stress is concentrated on specific spinal elements, then the fixation is strong, but the risk of complications during healing increases
Solution Approach 1:
The adjustable head design allows optimization of the stress distribution parameters by achieving proper alignment and angle adjustment. This distributes mechanical loads more evenly across the spinal elements during healing, maintaining fixation strength while reducing stress concentration that could lead to complications such as hardware failure or bone necrosis.
Data Source
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AI summary
A bone fastener includes a first member fixable with a proximal portion and includes a wall defining a groove. The wall includes an inner surface defining a first mating surface and a lateral surface defining a cavity. A second member is configured for fixation with the first member and includes a second mating surface engageable with the first mating surface. A third member defines an opening and is disposable with the groove such that the opening is aligned with the cavity. A distal portion includes a first end disposed within the members and a second end configured to penetrate tissue. The distal portion is movable relative to the proximal portion between a first orientation and a second orientation. Systems and methods are disclosed.