Polyaxial Spinal Cross Connector Assembly with Adjustable Span
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Solution Overview
Problem
Current spinal cross connectors face challenges in easy installation, secure attachment, height limitations, sizing, and ease of positioning between spinal rods, particularly in cervical spine fixation applications.
Innovation Solution
A spinal rod cross connector assembly with polyaxial heads that provide independent polyaxial positioning and adjustable fixation, using set screws to clamp onto spinal rods, allowing for adjustable connection and translation of a cross member between the heads for secure attachment and length adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If current spinal cross connectors are used to provide additional stability between spinal rods, then structural stability is improved, but installation complexity and difficulty of positioning increase
Solution Approach 1:
The cross connector is divided into separate components: a body portion with a first polyaxial head for attachment to the first spinal rod, and a second polyaxial head for attachment to the second spinal rod. This segmentation allows each head to be independently positioned and secured, simplifying the installation process while maintaining structural stability.
Solution Approach 2:
The cross connector incorporates polyaxial heads that allow for dynamic adjustment of the angle and orientation of the connector relative to the spinal rods. This dynamic positioning capability enables surgeons to optimize the connector's orientation for both ease of installation and maximum structural stability.
2Strength
If fixed-position cross connectors are used to connect spinal rods, then structural rigidity is improved, but adaptability to different anatomical configurations decreases
Solution Approach 1:
The polyaxial heads enable the cross connector to dynamically adapt to various anatomical configurations by allowing adjustment of the connector's angle and orientation. Once positioned, the connector provides rigid fixation to maintain the desired configuration, thus achieving both adaptability and structural rigidity.
Solution Approach 2:
The cross connector allows for changes in key parameters such as the angle of connection to the spinal rods and the distance between connection points. These parameter adjustments enable adaptation to different anatomical configurations while maintaining structural strength through secure polyaxial fixation.
3Adaptability or versatility
If adjustable cross connectors are used to provide positioning flexibility, then adaptability to different configurations is improved, but device complexity increases
Solution Approach 1:
The adjustable functionality is achieved through segmented polyaxial heads that can be independently adjusted and locked. This segmentation allows for positioning flexibility without requiring complex adjustment mechanisms throughout the entire connector, thus managing device complexity while maintaining adaptability.
Solution Approach 2:
The polyaxial heads incorporate self-locking mechanisms that automatically secure the connector in the desired position once adjusted. This self-service feature reduces the need for complex external locking mechanisms and simplifies the overall device design while maintaining positioning flexibility.
Data Source
AI summary
A spinal rod cross connector assembly for connection to adjacent spinal rods provides polyaxial positioning of polyaxial heads of the cross connector assembly relative to each spinal rod and which allows adjustment and fixation of the span of a cross connector or arm of the cross connector assembly between the two polyaxial heads through movement of the cross member relative to only one polyaxial head. Each polyaxial head has a clamp that provides attachment to the respective spinal rod and which allows the body of the polyaxial head to rotate relative thereto. Fixation of the orientation of a polyaxial head is achieved through placement and interaction of a set screw in the polyaxial head. The arm is preferably integral with and extends from a lateral side of one of the polyaxial heads. The second one of the polyaxial heads receives the arm and allows length adjustment relative thereto.