Multi-Channel Bone Screw Pressure Venting
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Solution Overview
Problem
During medical procedures like vertebroplasty and drug delivery, injecting materials through screws or tubes with single cannulations or fenestrations can lead to increased pressure at injection sites, causing complications such as fat embolisms and hypertension due to the difficulty in managing pressure effectively.
Innovation Solution
The use of devices and methods featuring multiple channels or screws with simultaneous positive and negative pressure control, allowing for controlled material injection and withdrawal to manage pressure and prevent material from flowing into undesirable areas, including configurations with dual-channel screws, plunger mechanisms, and external pressure-monitoring systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If material is injected through a single cannula or radially fenestrated cannula, then material delivery to the target location is achieved, but pressure increases at the injection site causing fat embolisms and hypertension
Solution Approach 1:
The single cannula is segmented into multiple separate cannulas or channels, each capable of independent material delivery. This segmentation allows distribution of injection pressure across multiple pathways, reducing peak pressure at any single site while maintaining effective material delivery to the target bone region.
Solution Approach 2:
A pressure-regulating intermediary mechanism is introduced between the material source and the injection site. This intermediary controls and modulates the pressure of injected material, preventing excessive pressure buildup that causes fat embolisms and hypertension while ensuring adequate material delivery.
2Productivity
If high pressure is used to force material through the cannula, then material delivery is achieved, but complications such as fat embolisms and hypertension occur
Solution Approach 1:
The material delivery system is divided into multiple cannulas or channels that work in parallel. This segmentation maintains high overall productivity by distributing material flow across multiple pathways while reducing the pressure burden on each individual pathway, preventing pressure-related complications.
Solution Approach 2:
Hydraulic or pneumatic pressure-regulating mechanisms are employed to control material delivery. These mechanisms use fluid dynamics principles to maintain optimal delivery pressure, ensuring efficient material transport while preventing excessive pressure that causes fat embolisms and hypertension.
3Device complexity
If a single cannula is used for material delivery, then device simplicity is maintained, but pressure control and safety are compromised
Solution Approach 1:
The single cannula is replaced with multiple cannulas or channels, each contributing to overall system reliability. While this increases device complexity, the segmentation provides redundant pathways for material delivery and improves pressure control, thereby enhancing safety and reliability.
Solution Approach 2:
The system parameters are changed by introducing multiple cannulas with different configurations, diameters, or orientations. This allows optimization of pressure distribution and material flow characteristics, improving safety and reliability while managing device complexity through parameter variation rather than fundamental design changes.
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 approach facilitates safer and more controlled material delivery by regulating pressure, reducing the risk of complications and ensuring uniform or asymmetrical distribution of materials as needed, thereby improving the efficacy of procedures like vertebroplasty and drug delivery.
Implementation Method 1
By simultaneously applying positive pressure at one site and negative pressure at the other site, injection is easier and material flows between the two sites
Implementation Method 2
The second method involves a plunger that can force material into bone if the plunger is advanced or lessen pressure if the plunger is withdrawn
Implementation Method 3
using a vacuum
Data Source
AI summary
A cannulated and possibly fenestrated device for injection of material into bone can be dangerous because large, uncontrolled pressures are introduced during injection into a somewhat closed system, and material may extrude undesirably or emboli may be introduced. Methods and devices are described for providing venting of pressure upon injection of material through cannulated and possibly fenestrated screws. The first method involves a bone screw and/or anchor device that includes multiple channels to allow material to flow in through one channel and out through another channel. The second method involves a plunger that can force material into bone if advanced or lessen pressure if withdrawn. The third method involves usage of two separate screws. Material is alternately injected or withdrawn from each screw to cause material to flow from one screw to the other in a controlled way that creates a uniform or asymmetrical distribution of material as desired.