Spinal Bone Anchor Attachment Device for Cortical Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current bone screws, particularly vertebral pedicle screws, fail to provide a permanent attachment to cortical bone, leading to loosening, shifting, and complications such as vascular and neurological deficits, dural tears, and pedicle fractures due to inadequate surface area interaction and improper placement, which affects patient outcomes in spinal fusion surgeries.
Innovation Solution
A spinal bone anchor attachment device with a multi-laterally split partial base and shaft, featuring bone engaging ridges and a biased tip, designed to increase the surface area interaction between the pedicle screw and cortical bone, enhancing stability and preventing screw loosening by expanding to engage the inner cortical bone portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional pedicle screw is inserted into the vertebral pedicle, then the screw can be placed through the cortical bone channel, but the screw fails to engage sufficiently with the cortical bone sides, leading to loosening and instability over time
Solution Approach 1:
The anchor device is divided into multiple segments including a distal expanded portion with lateral expansion elements, a shaft, and a proximal portion. The lateral expansion elements can be deployed independently to engage the cortical bone from multiple directions, providing segmented engagement points that distribute mechanical loads and prevent screw loosening.
Solution Approach 2:
The anchor device transitions from a linear insertion configuration to a three-dimensional expanded configuration within the vertebral pedicle. The lateral expansion elements deploy perpendicular to the screw axis, engaging the cortical bone sides in multiple spatial dimensions. This dimensional transformation creates a stable anchor that prevents loosening by engaging bone in radial and longitudinal directions simultaneously.
2Manufacturing precision
If the receiving channel is improperly formed during surgery, then screw placement accuracy is compromised, but the device must still achieve stable engagement with the cortical bone
Solution Approach 1:
The anchor device incorporates dynamic deployment mechanisms where the lateral expansion elements can be activated after insertion. This dynamic transformation allows the device to adapt to variations in receiving channel positioning, achieving reliable cortical bone engagement even when the initial insertion path was not perfectly accurate. The expansion elements can be deployed to compensate for placement deviations.
Solution Approach 2:
The device changes its geometric parameters from a compact insertion profile to an expanded engagement profile. The lateral expansion elements increase the effective engagement surface area and adjust the contact points with the cortical bone, allowing the device to achieve reliable engagement by modifying its physical parameters rather than requiring perfect initial placement precision.
3Strength
If the cortical bone channel provides insufficient surface area for screw engagement, then the screw loosens over time, but increasing the device size may compromise insertion through the pedicle
Solution Approach 1:
The lateral expansion elements are nested within the shaft during insertion, allowing the device to pass through the pedicle in a compact configuration. Once positioned, the expansion elements are deployed outward to engage the cortical bone, transforming from a space-efficient insertion profile to a large-surface-area engagement profile. This nested design enables both small insertion dimensions and large engagement surface area.
Solution Approach 2:
The device transitions dynamically between two states: a compact insertion state that fits through the pedicle receiving channel, and an expanded engagement state that provides maximum cortical bone contact. The lateral expansion elements are deployed after positioning, allowing the device to achieve large engagement surface area without compromising the ability to insert through the limited pedicle opening.
Data Source
AI summary
Spinal bone anchor attachment device for improving the attachment of a bone screw to skeletal portions of a patient, the device reducing the risk of screw failure, and improving patient outcomes. The device is composed of a biomaterial compatible with bone and provides an enhanced surface area on outer surfaces of the device for engaging the bone, and an enhanced surface area within the device for engaging the bone screw. The device may also have a guiding slanted tip with a bias element for facilitating the placement of the device into bone tissue and rescuing an improper tract. The device may further be used to secure the placement of pedicle screws, and as a component of an intervertebral stabilization system commonly used in spinal fusion surgeries.