Expandable Bone Fusion Screw for Vertebral Compression Control
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Solution Overview
Problem
Existing spinal fusion procedures require invasive incisions for screw and cage placement, and there is a need for improved methods to apply compression or distraction during spine stabilization operations.
Innovation Solution
A bone screw system with a threaded tip, main shaft, and threaded outer sleeve, allowing for minimally invasive insertion and rotation to achieve compression or distraction of vertebral bodies, combined with an expandable intervertebral cage for fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional open incision methods are used for screw and cage placement, then reliable bone fixation and fusion can be achieved, but patient trauma and surgical invasiveness increase significantly
Solution Approach 1:
The bone screw is divided into separate components: a main shaft with distal threads for bone engagement and a proximal threaded sleeve that can rotate independently. This segmentation allows the sleeve to be inserted through a minimally invasive approach while the main shaft remains anchored in the bone, combining minimal invasion with reliable fixation.
Solution Approach 2:
The threaded proximal sleeve is designed to fit over the distal portion of the main shaft, creating a nested configuration. The sleeve can rotate around the shaft to apply compression or distraction forces while both components work together to provide stable bone fixation through the minimally invasive access point.
2Reliability
If compression or distraction forces are applied during spine stabilization, then vertebral alignment and nerve root decompression improve, but control over the magnitude and direction of forces becomes more difficult
Solution Approach 1:
The threaded proximal sleeve is designed to rotate around the main shaft, allowing dynamic adjustment of compression or distraction forces. By rotating the sleeve, the surgeon can precisely control the magnitude and direction of forces applied to the vertebral bodies, improving both stabilization reliability and ease of force control.
3Reliability
If multiple incisions are made for cage and screw placement, then complete spinal stabilization can be achieved, but surgical time and patient recovery time increase
Solution Approach 1:
The bone screw system combines multiple functions in a single device: the main shaft provides anchorage in the bone, the threaded proximal sleeve enables compression/distraction forces, and the integrated design allows both components to be inserted through a single minimally invasive access point. This multi-functionality achieves complete spinal stabilization while reducing the number of incisions and surgical time.
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
Enables non-invasive stabilization of vertebrae with predictable compression/distraction, facilitating bone fusion through minimal incisions and expanded cage placement.
Implementation Method 1
The threaded outer sleeve has threads with a different (larger or smaller) pitch than the threads of the threaded tip so as to have anti-rotation properties
Implementation Method 2
The cage may be a cylinder defining a plurality of holes between a proximal end and a distal end
Data Source
AI summary
A method and system for performing bone fusion and/or securing one or more bones, such as adjacent vertebra, are disclosed. The screws include a threaded tip connected to a main shaft and a threaded outer sleeve that rotates relative to the outer shaft until locked down. Independent rotation of the threaded outer sleeve relative to the threaded distal tip allows compression or distraction to modify the gap between the vertebral bodies. The screws are passed from the inferior to superior vertebra or superior to inferior, for example, through a trans-pedicular route to avoid neurological compromise. At the same time, the path of screw insertion is oriented to reach superior or inferior vertebra. An intervertebral cage of the system is configured for lateral expansion from a nearly straight configuration to form a large footprint in the disc space. The screws and cage may be combined for improved fixation with minimal invasiveness.