Spinal Screw Fixation System with Adjustable Coupling Ring
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Solution Overview
Problem
Current spinal instrumentation systems require multiple screws for different directional movements and fixations, which complicates surgical procedures and limits versatility, as they typically function as either polyaxial or fixed/uniaxial screws but not all options are available with a single screw.
Innovation Solution
A fixation system that includes a cap housing the screw head, a coupling element with tabs to limit movement, and an adjusting ring, allowing the screw to function as polyaxial, uniaxial, or fixed, enabling conversion between these modes based on surgical needs with a single screw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple different screws are used for different directional fixations, then the versatility of spinal instrumentation is improved, but the device complexity and surgical procedure complexity increase
Solution Approach 1:
The patent applies universality by designing a single screw that can function in multiple modes (polyaxial, uniaxial, and fixed) through a unified structure. The screw includes a head with a spherical portion that can engage with different coupling elements, allowing one screw design to replace multiple specialized screw types while maintaining all their functions
Solution Approach 2:
The patent applies dynamics by making the screw's functional characteristics changeable rather than fixed. The screw can dynamically transition between polyaxial, uniaxial, and fixed modes during surgical procedure, allowing the surgeon to adjust the degree of freedom based on real-time surgical needs without changing the screw itself
2Adaptability or versatility
If multiple different screws are used for different directional fixations, then the versatility of spinal instrumentation is improved, but the ease of operation during surgical procedure deteriorates
Solution Approach 1:
The unified screw design with universal head structure allows surgeons to use a single screw type for all fixation needs, eliminating the complexity of selecting and handling multiple specialized screw types during surgery while maintaining full functional versatility
3Device complexity
If a single screw is designed to provide all fixation options, then the device complexity is reduced, but the difficulty of achieving precise directional control increases
Solution Approach 1:
The patent applies segmentation by dividing the single screw system into distinct functional components: the screw body, the spherical head portion, and interchangeable coupling elements. This segmentation allows precise directional control through the coupling element design while maintaining the simplicity of a unified screw approach
Solution Approach 2:
The patent uses the spherical head portion as an intermediary between the screw body and the coupling elements. This intermediary structure enables precise directional control by allowing different coupling elements to engage with the sphere at specific orientations, providing accurate angular positioning while maintaining a simple unified screw design
Data Source
AI summary
A fixation system for spinal instrumentation comprising a cap (1), which houses the head of a screw (2), the end of said screw (2) projecting through a lower opening of said cap (1). A coupling element (3) having two tabs (33) on both side ends rests on the upper part of the head of said screw (2). Said coupling element (3) houses therein an adjusting ring (4) secured to a series of tabs (7), by which means the movement of the head of said screw (2) can be limited.