Deployable Bone Anchor for Single-Step Spinal Fixation
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Solution Overview
Problem
Traditional bone anchors for spinal fixation require multiple steps and often violate the superior facet joint, limiting their application to specific orientations and increasing surgical complexity.
Innovation Solution
A bone anchor with a deployable purchase element that can be applied in various orientations, including cephalad, allowing for a single-step secure attachment to the bone structure without violating the superior facet joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hooks are placed in caudal orientation to maintain purchase on vertebral body, then fixation stability is improved, but superior facet joint must be violated and surgical complexity increases
Solution Approach 1:
The bone anchor incorporates a deployable purchase element that transitions from a non-deployed to deployed state, allowing dynamic adaptation to bone geometry. This enables the anchor to achieve stable fixation without requiring precise pre-planning of trajectory and orientation, thereby reducing surgical complexity while maintaining fixation reliability
Solution Approach 2:
The purchase element's deployability allows change in its geometric parameters (extension into cavity) after implantation. This parameter change enables the anchor to achieve optimal bone engagement regardless of initial insertion orientation, eliminating the need to violate the superior facet joint while maintaining fixation stability
2Reliability
If traditional hooks are placed in caudal orientation, then purchase on vertebral body is maintained, but application is limited to specific orientations
Solution Approach 1:
The deployable purchase element provides dynamic adjustment capability after implantation. Regardless of the initial insertion orientation (cephalad, caudal, lateral, or oblique), the purchase element can deploy to engage the bone structure optimally, thereby maintaining reliable purchase while enabling application in multiple orientations
Solution Approach 2:
The bone anchor design integrates both the rod-housing component and deployable purchase element into a single multi-functional device. This universal design allows the anchor to function effectively in various orientations and anatomical locations, eliminating the limitation to specific orientations while ensuring reliable bone engagement
3Reliability
If hook/claw constructs or hook with screw implants are used to achieve enhanced purchase, then fixation reliability is improved, but multiple steps are required and surgical complexity increases
Solution Approach 1:
The invention merges the rod-housing component and the purchase element into a single integrated bone anchor device. The deployable purchase element is incorporated directly into the rod-housing structure, allowing both components to function together in a single implantation step, thereby achieving enhanced fixation reliability without increasing surgical complexity
Solution Approach 2:
The purchase element is pre-configured within the rod-housing component in a non-deployed state during manufacturing. This preliminary configuration allows the device to be implanted as a single unit, with the purchase element automatically deploying after insertion to engage the bone structure, eliminating the need for separate implantation steps while ensuring fixation reliability
Data Source
AI summary
A bone anchor is provided for connecting a rod to a bone structure, the bone anchor having a rod housing configured to accommodate the rod; a cavity distal to the rod housing dimensioned to accommodate the bone structure; and a deployable purchase element capable of assuming a deployed position in which the purchase element protrudes into the cavity, and capable of assuming a non-deployed position in which the purchase element does not substantially protrude into the cavity.