Bone Anchor Removal Guide With Dovetail Groove
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Solution Overview
Problem
Current systems for removing bone fixation elements, such as anchors from joint prostheses, lack efficient methods for secure and effective extraction, particularly from channels with complex geometries like dovetailed or undercut designs.
Innovation Solution
A system comprising a removal guide with a groove coaxially aligned with the channel and an instrument featuring a grasping feature and engagement feature, such as a dovetail or hook, allows for the anchor to be slidably removed along a defined removal axis by engaging the anchor's support structure and overcoming resistance for secure extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional removal methods are used for bone anchors in channels with complex geometries (dovetailed or undercut designs), then the anchor can be removed, but the removal process becomes difficult and potentially damaging to the implant or surrounding tissue
Solution Approach 1:
A removal guide is introduced as an intermediary tool between the anchor removal instrument and the bone anchor. The removal guide includes a groove that is coaxially aligned with the channel, providing a guided path for the instrument. This intermediary structure enables secure engagement with the anchor's support structure while preventing off-axis forces that could damage the implant or surrounding tissue during removal.
Solution Approach 2:
The removal system is divided into distinct functional components: the removal guide with its groove for positioning, the instrument with its grasping feature for engaging the anchor, and the engagement feature for interacting with the groove. This segmentation allows each component to be optimized for its specific function, making the overall removal process more effective and safer.
2Reliability
If a secure grasping mechanism is used to engage the anchor's support structure, then effective extraction is achieved, but the complexity of the removal instrument increases
Solution Approach 1:
The engagement feature on the instrument is designed with an asymmetric dovetail shape that complements the corresponding groove in the removal guide. This asymmetric design provides secure mechanical engagement through interlocking surfaces, ensuring reliable grasping of the anchor while maintaining a relatively simple instrument structure. The asymmetric geometry prevents premature disengagement and ensures force transmission during extraction.
Data Source
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AI summary
Systems and methods for bone anchor removal include a removal guide (100) and a removal instrument. The removal guide includes a series of grooves (104) for guiding the removal instrument (50) to the anchors, and for removal of the anchor (20). The removal instrument includes a distal working end (56) with a grasping feature (68) designed to engage a portion of the bone anchor and an engagement feature (74) designed to engage the grooves of the removal guide for anchor removal.