Spinal Trauma Fixation Guide for Rod-Free Alignment Correction
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Solution Overview
Problem
Existing posterior spinal fixation constructs face limitations in achieving desired correction due to the presence of the rod, which allows limited movement of anchors, hindering effective reorientation of damaged spinal structures during trauma repair.
Innovation Solution
A system comprising a guide member with a pivot rack and locking rack that allows for relative rotation and translation of bone anchor assemblies, enabling angulation, distraction, and compression of vertebral bodies, facilitating alignment correction without the need for a spinal rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rod is used to connect anchors in posterior spinal fixation, then the fixation construct provides stability, but the rod limits the movement of anchors, reducing the ability to achieve desired correction
Solution Approach 1:
The system divides the fixation construct into modular components: anchors, extenders, and connectors that can be independently positioned and adjusted. This segmentation allows each component to be optimized for its specific function while maintaining overall stability, resolving the contradiction between rigid stability and flexible adjustability.
Solution Approach 2:
The fixation construct incorporates dynamic elements including threaded extenders that allow continuous adjustment of anchor position, and connectors that permit controlled movement during correction procedures. These dynamic features enable the construct to adapt during surgery while maintaining stability once positioned.
2Manufacturing precision
If anchors are manipulated about a rod to compress, distract, and angulate vertebral bodies, then correction can be achieved, but the rod permits limited movement before anchors bottom out or run against the rod
Solution Approach 1:
The extender components serve as intermediaries between the anchors and the connectors, providing a controlled mechanism for compression, distraction, and angulation. These extenders act as mediators that enable precise manipulation of vertebral bodies without the limitations of direct rod-to-anchor interaction.
Solution Approach 2:
The system enables continuous adjustment of multiple parameters including the distance between anchors, the angle of correction, and the degree of compression or distraction. Threaded extenders allow incremental changes in these parameters, providing precise control over the correction process.
3Reliability
If traditional posterior spinal fixation constructs are used for trauma correction, then stability is provided, but permanent fusion is not the primary goal and the constructs are not optimized for reorientation of damaged spinal structures
Solution Approach 1:
The fixation construct is designed with multi-functional capabilities, serving both as a stabilization device and as a correction tool for trauma cases. The same modular components that provide stability also enable reorientation and alignment correction, making the system versatile for different surgical goals without requiring separate specialized constructs.
Data Source
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AI summary
A system comprises a bone anchor assembly (2) and a guide member (12) for positioning and angulating the bone anchor assembly. The guide member comprises a proximal end and a distal end a lumen (58) extending therebetween. A pair of opposed longitudinal rod slots (34) opening to the distal end and extending proximally for a length along the guide member (12) and contiguous with the lumen (58), form a rod channel (80) dimensioned to guide a spinal rod (6) into the bone anchor assembly (2). A bone anchor engagement feature (42) is provided at the distal end and a side track (46) extends longitudinally between the pair of opposed longitudinal rod slots (34).