Articulating Spinal Crosslink Ball Joint Alignment
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Solution Overview
Problem
Current crosslink apparatuses in spinal fusion constructs have limited range of motion, making alignment difficult for surgeons and can cause loosening of rods from pedicle screws due to expansion of the screw head, leading to instability in the construct.
Innovation Solution
An articulating crosslink apparatus with a ball joint and expandable collet that securely attaches to the pedicle screw without expanding its head, allowing for spherical articulation and adjustable alignment of crosslink arms, utilizing a joint locking element to secure the ball joint and collet in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If currently available crosslinks are used to connect rods in a spinal fusion construct, then the crosslink provides structural connection, but the crosslink has very limited range of motion which makes it difficult for a surgeon to properly align and connect with other elements
Solution Approach 1:
The crosslink apparatus incorporates a ball joint mechanism that allows dynamic articulation between the first and second arms. The ball joint includes a spherical head that rotates within a socket, enabling the crosslink to adapt to different alignment requirements during spinal fusion surgery while maintaining secure connection between rods.
2Reliability
If currently available crosslinks attach to pedicle screws, then connection is provided, but the attachment method causes expansion of the head of the pedicle screw which can lead to loosening of the rod from the pedicle screw
Solution Approach 1:
The invention extracts the attachment mechanism from the traditional expansion-based system and replaces it with a ball joint interface that attaches to the pedicle screw head without causing expansion. The ball joint connects to the rod while the expandable collet secures the assembly to the pedicle screw, separating the connection function from the expansion function.
Solution Approach 2:
The ball joint serves as an intermediary component between the crosslink arms and the pedicle screw-rod assembly. This intermediary mechanism allows the crosslink to connect to the spinal construct without directly expanding the pedicle screw head, thereby preventing loosening while maintaining secure attachment.
3Ease of operation
If an articulating crosslink with ball joint is implemented, then spherical articulation and easier alignment are achieved, but the device complexity increases with multiple components including ball joint sockets, locking points, and expandable collet
Solution Approach 1:
The ball joint socket and locking mechanism are integrated into a unified structure where the socket itself contains the locking points and locking elements. The expandable collet is combined with the ball joint assembly, merging multiple functions into integrated components that reduce the number of separate parts while maintaining articulation and security functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the stability and ease of alignment of crosslink components in spinal fusion constructs by allowing for secure attachment to pedicle screws without expanding the screw head, reducing the likelihood of loosening and improving the overall fit and stability of the construct.
Implementation Method 1
an articulating joint formed with one or more ball joint sockets and one or more joint locking points, a ball joint retained by each of the ball joint sockets
Implementation Method 2
an expandable collet... a collet securing means that fastens to the expandable collet to cause the expandable collet to engage with the attachment collar
Implementation Method 3
a joint locking element for each of the joint locking points, wherein the joint locking element secures the ball joint within the articulating joint body
Data Source
AI summary
The present invention generally relates to a crosslink for linking a pair of rods in a spinal fusion construct. Specifically, this invention relates to an articulating crosslink that attaches directly to the head of a pedicle screw.