Spinal Clamp With Dynamic Adjustment For Misalignment
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Solution Overview
Problem
Existing cross-connecting devices for spinal fixation systems lack sufficient adjustability in multiple degrees of freedom, which limits their ability to accommodate translational, rotational, and angular misalignments between connected spinal fixation devices.
Innovation Solution
A clamp design with a slotted rod-receiving interface and expansion portions that snap onto the rod, combined with a lever mechanism and stop feature to secure the rod, allowing for adjustable and secure attachment of cross-connecting devices to spinal fixation systems, enabling translational, rotational, and angular adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed rigid clamp design is used, then structural stability is improved, but adaptability to misalignments deteriorates
Solution Approach 1:
The clamp incorporates a dynamic adjustment mechanism that allows the rod-receiving interface to move relative to the cross-connecting device. This includes a slot in the outer body that permits longitudinal movement, and a rotatable inner body that enables angular adjustment, allowing the clamp to adapt to misalignments while maintaining structural stability through controlled motion rather than rigid fixation
Solution Approach 2:
The clamp is divided into separate functional components: an outer body that provides structural support, an inner body that receives the rod, and a set screw that provides adjustment capability. This segmentation allows each component to perform its specific function independently, with the inner body capable of rotating within the outer body to accommodate angular misalignments while the outer body maintains overall structural integrity
2Device complexity
If a simple clamp design is used, then device complexity is reduced, but adjustability in multiple degrees of freedom deteriorates
Solution Approach 1:
The clamp achieves multi-degree-of-freedom adjustability through a relatively simple mechanism: the inner body can rotate within the outer body to provide angular adjustment, while the set screw allows longitudinal positioning along the rod. This dynamic capability enables adjustment in multiple degrees of freedom without requiring a complex mechanism with multiple actuators and control systems
Solution Approach 2:
The clamp design allows the surgeon to directly adjust the clamp's position and orientation using simple manual manipulation of the set screw and rotation of the inner body, without requiring complex control systems or multiple adjustment mechanisms. The design serves itself by providing inherent adjustability through its basic mechanical structure
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 clamp design provides enhanced adjustability and secure attachment of cross-connecting devices, accommodating misalignments and improving the stability and flexibility of spinal fixation systems during surgical procedures.
Implementation Method 1
The slotted rod-receiving interface can include a rod-receiving portion configured to snap onto the rod
Implementation Method 2
The rod-receiving portion of the slotted rod-receiving interface can be configured to be tightened onto the rod as the set screw is driven into the internally threaded bore
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A clamp for attaching a cross connecting device to a spinal fixation system comprising an outer body and an inner body. The outer body defines an internally threaded bore and an outer body cavity, and the inner body defines an inner body cavity. The inner body is at least partially disposed within the outer body. A pin is provided for connecting the inner and outer bodies to each other, while allowing for a limited amount of movement therebetween. A set screw suitable for being driven into the internally threaded bore is provided for securing the inner body to the spinal fixation system.