Offset Bone Anchor With Adjustable Rod Connector
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Solution Overview
Problem
Existing spinal fixation constructs face challenges in connecting rods to non-coplanar bone anchors and navigating anatomical obstructions during spinal fusion procedures, which can complicate the placement of fixation systems and obstruct access to the spine.
Innovation Solution
The use of offset bone anchor assemblies with adjustable rod connectors that decouple the rod position from the shank, allowing for medial or lateral offset placement and accommodating anatomical obstructions, enabling easier alignment and reduced hardware interference during surgical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional bone anchors with fixed rod connectors are used, then the structure is simple, but the rod cannot be connected to non-coplanar anchors and hardware interferes with surgical access
Solution Approach 1:
The bone anchor is divided into separate functional components: a shank for bone engagement, a connector body, and a rod receiving portion. This segmentation allows each component to be optimized independently - the shank for secure bone fixation and the connector for flexible rod attachment, resolving the contradiction between operational ease and structural simplicity.
Solution Approach 2:
The rod connector is designed with offset positioning and multi-angular capability, transitioning from a single-plane connection to three-dimensional multi-directional connection. This allows the rod to connect to anchors that are not coplanar, solving the accessibility problem while maintaining reasonable structural complexity.
2Ease of operation
If the rod connector is positioned directly on the anchor shank, then the structure is compact, but the hardware obstructs access to the spine
Solution Approach 1:
An offset connector body is introduced as an intermediary element between the anchor shank and the rod. This mediator positions the rod away from the spine, clearing the surgical pathway and improving access while adding only moderate volume to the overall assembly.
3Reliability
If the rod is bent to match anchor positions, then connection is achieved, but the rod experiences excessive stress and alignment precision is lost
Solution Approach 1:
The rod connector is designed with dynamic adjustment capability, allowing the rod to be positioned at multiple angles and orientations relative to the anchor shank. This dynamic positioning eliminates the need to bend the rod, maintaining rod integrity and reducing stress while achieving precise alignment through the connector's degrees of freedom.
Data Source
AI summary
This disclosure describes example an surgical fixation anchor and methods for implanting the surgical fixation anchor on the spine as part of a spinal fixation construct. The surgical fixation anchor can be coupled to a spinal rod. The coupling between the spinal rod and the anchor can be offset from an axis of the anchor. The position and orientation of the coupling to the spinal rod can also be transnationally and rotationally adjusted relative to the anchor to facilitate the coupling and/or to optimize space usage adjacent to the fixation construct.