Dynamic Multi-Axial Fastener for Spinal Stability
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Solution Overview
Problem
Proximal Junctional Kyphosis (PJK) occurs in long spinal constructs due to muscle weakening, disruption of the posterior tension band, and pre-existing kyphotic hyperflexion, leading to facet dislocation and posterior widening of the disc space, which existing devices fail to adequately address.
Innovation Solution
The development of a device comprising an anchor with a receiver and a dampener, where the receiver includes slots and a channel to securely attach an elongated member to a vertebral member, with a flexible dampener positioned within the receiver to absorb and distribute forces, reducing the risk of PJK by allowing controlled movement and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid spinal construct is used to stabilize the spine, then spinal stability is improved, but the risk of Proximal Junctional Kyphosis (PJK) increases due to excessive stress concentration
Solution Approach 1:
The receiver is designed to change its structural parameters dynamically by allowing controlled movement between locked and unlocked positions. In the locked position, the receiver provides rigid stabilization; in the unlocked position, it allows controlled motion to distribute stresses and reduce PJK risk. This parameter change enables the system to adapt to different physiological and mechanical demands.
Solution Approach 2:
The device transitions from a static rigid construct to a dynamic system that can adapt its stiffness. The receiver's ability to move between locked and unlocked states, and the controlled translational/rotational movement capability, create a dynamic spinal construct that can respond to physiological movements and distribute loads more evenly, reducing stress concentration at junctional levels.
2Stability of the object's composition
If a fixed spinal construct is used to prevent movement, then spinal alignment is maintained, but the risk of facet dislocation and disc space widening increases
Solution Approach 1:
The device allows controlled dynamic movement through the receiver's translation and rotation capabilities. This controlled motion prevents the excessive stress concentration that leads to facet dislocation and disc space widening, while still maintaining overall spinal alignment through the anchored connection to the vertebral body.
Solution Approach 2:
The device provides beforehand cushioning by allowing controlled movement that absorbs and distributes physiological stresses before they can concentrate at vulnerable junctional levels. The receiver's mobility acts as a buffer that protects adjacent structures from harmful stress concentrations.
3Strength
If a rigid anchor is used to securely attach the elongated member, then attachment strength is improved, but the device cannot accommodate physiological movement
Solution Approach 1:
The anchor system combines strong initial attachment with dynamic adaptability. The anchor secures the receiver to the vertebral body with sufficient strength, while the receiver itself provides the dynamic movement capability. This separation of functions allows the system to maintain both strong attachment and physiological movement accommodation.
Solution Approach 2:
The device is segmented into distinct functional components: the anchor provides strong attachment to the vertebral body, while the receiver provides controlled movement capability. This segmentation allows each component to optimize its specific function - the anchor for strength and the receiver for adaptability - while working together as an integrated system.
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
The device effectively reduces or eliminates PJK by providing controlled translational and rotational movement, thereby stabilizing the spine and distributing stress, which helps in maintaining proper spinal alignment and reducing the risk of facet dislocation and disc space widening.
Implementation Method 1
a flexible dampener positioned within the receiver to absorb and distribute forces
Data Source
AI summary
A device for attaching an elongated member to a vertebral member and provide for dampened movement of the elongated member. The device may include a receiver that receives an elongated member. The receiver may be movably attached to an anchor that may be attached to a vertebral member. A dampener may be positioned within the receiver. Further, one or more slots may be positioned in the receiver. The dampener and/or slots dampen the translational movement of the receiver and attached elongated member relative to the anchor in first and second directions, and may also buffer forces applied into the spine.