Posterior Spinal Fixation With Rotatable Rod Receivers
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Solution Overview
Problem
Traditional spinal fixation systems face limitations in multi-level constructs due to the need for a single rod that restricts bone anchor placement and requires extensive manipulation, which can lead to suboptimal alignment and structural weakness during spinal surgeries.
Innovation Solution
A spinal fixation system comprising an interior fixation assembly, an open fixation assembly, and an end fixation assembly, featuring rotatable rod receivers and connection members that allow for angular offset of rod projections, enabling flexible and stable fixation across multiple vertebrae levels without the need for extensive rod manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single rod is used to extend the length of the construct, then the spinal fixation system can span multiple levels, but the placement of bone anchors is limited by the shape of the rod and requires extensive manipulation
Solution Approach 1:
The single rod is divided into multiple discrete rod segments, each with a standardized receiver and connection member configuration. This segmentation allows each bone anchor to be placed independently at optimal positions on the vertebral bodies, eliminating the constraint of fitting a continuous rod through all anchors. The rod segments can be connected after placement to form the complete spinal fixation construct.
2Stability of the object's composition
If a single rod extends along the entire spinal construct, then the structure is continuous, but extensive manipulation of the rod and vertebral segments is required
Solution Approach 1:
The rod segments are pre-assembled with their receivers and connection members before the surgical procedure. This preliminary preparation allows the bone anchors to be placed first at the optimal positions on each vertebra, and then the pre-prepared rod segments are simply connected to complete the construct. This eliminates the time-consuming manipulation of a single continuous rod through multiple vertebral levels during surgery.
3Ease of manufacture
If bone anchors are placed along a relatively linear path, then the rod placement is simplified, but the alignment may not be optimal based on the underlying bone anatomy
Solution Approach 1:
Each rod segment is designed with a receiver and connection member that can accommodate local anatomical variations at each vertebral level. The standardized interface allows each bone anchor to be placed at the optimal position on its respective vertebra, tailored to the local bone anatomy, while still maintaining compatibility with adjacent segments. This enables precise, individualized placement at each level rather than forcing a uniform linear path.
4Adaptability or versatility
If spinal manipulation occurs along the entire construct, then all vertebral segments can be captured, but the complexity of manipulating both rod and vertebrae increases
Solution Approach 1:
The spinal fixation construct is divided into separate rod segments that can be independently manipulated and positioned. This segmentation allows the surgeon to focus manipulation efforts on specific vertebral levels that require correction, rather than manipulating the entire construct uniformly. Each rod segment can be adjusted independently to achieve the desired spinal alignment, reducing the overall complexity of the manipulation procedure.
Data Source
AI summary
A spinal fixation device may include a bone anchoring member, a rod receiver, and an connection member. The rod receiver may include a channel for receiving a rod projection from a first adjacent fixation assembly. The rod receiver may have a central axis such that the channel is generally perpendicular to the central axis. The connection member may have a rod projection configured to extend to a second adjacent fixation assembly. The rod receiver may be coupled to the connection member and rotatable about the central axis of the rod receiver. The interior fixation assembly may be axially fixed such that the bone anchoring member, the rod receiver and the connection member are not translatably movable relative to each other.