Supplemental Fixation Screw Polyaxial Housing Spinal Stability
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Solution Overview
Problem
Existing spinal fixation systems face challenges in stabilizing the lower spine due to high failure rates of pedicle screws at the sacral level, particularly due to anatomical constraints and increased load-bearing capacity, leading to loosening or breakage, which compromises surgical stability and patient comfort.
Innovation Solution
A spinal fixation system with a supplemental screw assembly that includes a housing with polyaxial adjustability and strong connections, allowing for flexible placement and orientation of primary and secondary fixation screws to accommodate varying anatomical variations, thereby enhancing fixation strength and torsional rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pedicle screws are used for spinal fixation at the sacral level, then fixation is provided, but the screws are prone to loosening or breakage due to increased load and anatomical constraints
Solution Approach 1:
The fixation system is divided into multiple independent components: a first fixation screw, a second fixation screw, and a cross connector. This segmentation allows each component to be optimized for its specific function while working together to provide overall stabilization, reducing the failure risk of any single screw.
Solution Approach 2:
Different fixation screws are positioned at specific locations (first and second fixation locations) with different orientations relative to the spinal rod. The cross connector is strategically placed to bridge the gap between screws. This local optimization ensures that each component addresses specific stress patterns and anatomical constraints at its location.
2Reliability
If multiple fixation screws are added to increase fixation strength, then reliability improves, but device complexity increases
Solution Approach 1:
The first fixation screw, second fixation screw, and cross connector are merged into a single integrated assembly that attaches to the spinal rod through one interface mechanism. This combining approach provides multiple fixation points while maintaining a unified structure that simplifies installation and reduces overall system complexity.
Solution Approach 2:
The cross connector serves multiple functions simultaneously: it connects the first and second fixation screws, provides additional structural support, and distributes mechanical loads across the fixation system. This multi-functionality reduces the need for separate components, thereby reducing complexity.
3Reliability
If fixation screws are made stronger to withstand increased load, then fixation reliability improves, but the surgical field and trauma increase
Solution Approach 1:
The fixation system is divided into multiple independent components: a first fixation screw, a second fixation screw, and a cross connector. This segmentation allows each component to be optimized for its specific function while working together to provide overall stabilization, reducing the failure risk of any single screw.
Solution Approach 2:
The cross connector includes a polyaxial joint that allows dynamic adjustment of the fixation screws' orientation and position during surgery. This dynamic capability enables the surgeon to optimize the fixation configuration for each patient's specific anatomy without requiring overly aggressive surgical intervention, thereby reducing trauma.
Data Source
AI summary
Devices, systems and methods for surgical fixation, including multi-screw anchoring devices for anchoring to various anatomical locations such as a sacral level or other anatomy of the spine. Anchoring devices include screw assemblies that are adjustable in a variety of different ways to grant a surgeon various options for placement and/or orientation of the primary and supplemental fixation screws.