Tapered Bone Anchor Resists Eccentric Loads
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Solution Overview
Problem
Current tissue anchor technologies face challenges in providing sufficient pull-out resistance and stability with minimal tissue penetration, especially in delicate areas like the spine, and often require expansion or mushrooming mechanisms that can damage surrounding tissue.
Innovation Solution
The development of bone anchors with a tapered cross-section and offset planes that resist backout or migration under eccentric loads, featuring a recessable design that can be press-fit into bone without expansion, and a keel-like structure for enhanced stability and resistance to torsional loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tissue anchors are used to provide sufficient pull-out resistance and stability, then the anchor can be securely fixed in tissue, but the anchor requires expansion or mushrooming mechanisms that damage surrounding tissue
Solution Approach 1:
The anchor employs a tapered cross-section with varying geometry along its length, transitioning from a narrower distal end to a wider proximal end. This geometric parameter change allows the anchor to achieve mechanical interlocking and resistance to pull-out forces without requiring expansion or mushrooming mechanisms that would damage surrounding tissue
Solution Approach 2:
The anchor is constructed from a combination of materials with different properties - a rigid tapered body for structural integrity and pull-out resistance, coupled with a flexible membrane or fabric component for tissue compatibility and comfort. This composite structure provides both the necessary mechanical strength and reduced tissue damage
2Reliability
If the anchor penetrates deeper into tissue to increase stability, then the anchor resistance to pull-out forces, but the amount of tissue damage and disruption increases
Solution Approach 1:
The anchor features localized functional zones: a tapered distal portion for minimal-penetration insertion and anchoring, a midsection with optimized geometry for stability, and a proximal portion with attachment features for securing the graft. This local quality differentiation allows the anchor to achieve stability without requiring deep uniform penetration throughout its entire length
Solution Approach 2:
The anchor utilizes a three-dimensional tapered geometry that distributes anchoring forces across multiple spatial dimensions. The varying cross-sectional area along the length creates mechanical interlocking in radial directions while the overall shape controls penetration depth, achieving stability without excessive tissue disruption
3Ease of manufacture
If the anchor uses a uniform cross-section design, then the manufacturing process is simpler, but the anchor provides insufficient resistance to eccentric and torsional loads
Solution Approach 1:
The anchor employs an asymmetric tapered cross-section that is narrower at the distal end and wider at the proximal end. This asymmetric geometry provides enhanced resistance to eccentric and torsional loads by creating favorable stress distributions and mechanical interlocking, while still maintaining relative manufacturing simplicity through consistent tapering along the length
4Reliability
If the anchor requires expansion or mushrooming mechanisms to achieve stability, then the pull-out resistance is improved, but the device complexity and potential for tissue damage increase
Solution Approach 1:
The invention extracts and eliminates the expansion or mushrooming mechanism from the anchor design. Instead of using a uniform cross-section that requires post-insertion expansion, the anchor incorporates a tapered cross-section that achieves stability and pull-out resistance through its geometry alone, thereby reducing device complexity and eliminating the associated tissue damage
Data Source
AI summary
Methods of inserting and retaining interbody fusion material are disclosed. In some embodiments, the methods include inserting an anchored implant comprising a bone anchoring portion and an engagement portion. A method may also include inserting at least one bone fusion material within a disc space between two adjacent vertebral bodies. In some embodiments, a method includes driving the bone anchoring portion into an outer surface of at least one of the adjacent vertebral bodies and recessing the bone anchoring portion within the outer surface of the at least one adjacent vertebral body.