Spinal Stabilization Rods with Asymmetrical Motion Limiting
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Solution Overview
Problem
Existing spinal stabilization devices fail to provide asymmetrical vertebral motion effectively, particularly in controlling the extent of flexion and extension movements, which is crucial for maintaining proper spinal alignment and reducing pain and neurological deficits caused by vertebral damage.
Innovation Solution
The use of a rod system with anchors and elastic members that control the movement between the rod and anchors, allowing for asymmetrical motion by applying increasing force as the vertebral members move, thereby limiting the range of motion to prevent excessive flexion or extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rod system with anchors is used to stabilize vertebral members, then spinal alignment is improved and pain is reduced, but the ability to control asymmetrical motion between flexion and extension is insufficient
Solution Approach 1:
The device divides the motion control function into separate components: a first limiting device for flexion motion and a second limiting device for extension motion. Each limiting device is independently positioned and adjusted, allowing precise control of asymmetrical motion while maintaining overall spinal stabilization through the rod-anchor system.
Solution Approach 2:
The limiting devices are designed to be adjustable and repositionable along the rod, enabling dynamic adaptation to different patient requirements and motion patterns. This allows the device to provide tailored motion control for flexion and extension while maintaining spinal alignment stability.
2Stability of the object's composition
If the rod is fixedly connected to both anchors, then spinal stabilization is maximized, but vertebral motion in multiple directions is overly restricted
Solution Approach 1:
The device applies different connection characteristics to different locations along the rod: the first anchor provides fixed connection for maximum stabilization, while the second anchor allows controlled motion through the limiting device. This local differentiation enables simultaneous spinal stabilization and controlled vertebral motion in flexion and extension directions.
Solution Approach 2:
The limiting devices are positioned asymmetrically on the rod to create different motion characteristics for flexion and extension. By placing the first limiting device closer to the first anchor and the second limiting device closer to the second anchor, the system creates asymmetrical motion control that matches natural vertebral movement patterns while maintaining overall stability.
3Ease of operation
If limiting devices are added to control motion extent, then asymmetrical motion control is improved, but device complexity increases
Solution Approach 1:
The limiting devices are integrated with the existing rod-anchor system rather than being separate add-on components. The limiting devices utilize the rod's structural elements and the anchors' positioning capabilities, merging the motion control function with the stabilization function to reduce overall device complexity while maintaining motion extent control.
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
This solution enables controlled and asymmetrical vertebral motion, providing additional range of motion in flexion over extension, thus addressing the limitations of existing devices in managing spinal alignment and reducing pain and neurological deficits.
Implementation Method 1
The rod may be fixedly connected to the first anchor, and movably connected to the second anchor. A limiting device may be positioned on one or both sides of the second anchor. The limiting device controls an extent of movement between the rod and the second anchor during vertebral motion in first and second directions.
Data Source
AI summary
The present application is directed to methods and devices that provide for asymmetrical movement of vertebral members. In one embodiment, first and second anchors connect the rod to the vertebral members. The rod may be fixedly connected to the first anchor, and movably connected to the second anchor. A limiting device may be positioned on one or both sides of the second anchor. The limiting device or devices control an extent of movement between the rod and the second anchor during vertebral motion. In one embodiment, the device controls an amount of flexion and extension of the vertebral members.