Bone Cement Mixing Cartridge with Sealed Feedthrough
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Solution Overview
Problem
Existing bone cement mixing devices often result in air bubbles during the mixing of polymethylmethacrylate (PMMA) bone cement, leading to compromised mechanical properties, and require complex handling procedures, additional equipment, and sterilization challenges, which can lead to user errors and increased costs.
Innovation Solution
A full-prepacked mixing system with a cartridge design that allows for the separate storage and mixing of cement powder and monomer liquid without external extrusion devices, using a cylindrical cartridge with a dispensing plunger and conveying plunger to ensure gas-free mixing and dispensing of the bone cement dough, eliminating the need for vacuum sources and manual mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement powder and monomer liquid are mixed in conventional mixing beakers with spatulas, then the mixing process is simple and equipment is minimal, but air bubbles are enclosed in the bone cement dough which compromises mechanical properties
Solution Approach 1:
The mixing device is segmented into distinct functional zones: a first hollow space for receiving cement powder, a second hollow space for receiving monomer liquid, and a feedthrough structure that separates and connects these spaces. This segmentation allows independent loading of components while preventing premature mixing, thereby eliminating air bubble incorporation during the mixing process.
Solution Approach 2:
The cement powder and monomer liquid are pre-loaded into separate hollow spaces before mixing occurs. The feedthrough structure is pre-positioned to control the mixing interface. This preliminary arrangement ensures that mixing occurs in a controlled manner without introducing air bubbles, improving the reliability of the bone cement's mechanical properties.
2Reliability
If vacuum cementing systems are used to prevent air inclusions in bone cement dough, then air bubbles are eliminated, but the system requires complex vacuum equipment and multiple working steps increasing user error potential
Solution Approach 1:
The harmful vacuum system has been extracted and replaced by a simplified feedthrough-based mixing mechanism. The feedthrough structure enables controlled mixing of cement powder and monomer liquid without requiring vacuum equipment, thereby eliminating air bubbles while reducing device complexity and user error potential.
Solution Approach 2:
The mixing device performs the air-elimination function inherently through its feedthrough structure design, without requiring external vacuum systems. The controlled mixing interface self-regulates to prevent air bubble incorporation, making the system simpler and more reliable for achieving air-free bone cement dough.
3Adaptability or versatility
If full-prepacked mixing systems with separate compartments are used, then storage and mixing are integrated, but complex handling procedures and sterilization challenges increase user error and costs
Solution Approach 1:
The storage and mixing functions are merged into a single integrated device with a first hollow space for cement powder storage and a second hollow space for monomer liquid storage. The feedthrough structure combines the separation and mixing functions, allowing integrated storage and mixing while simplifying handling procedures and reducing user error.
Solution Approach 2:
The mixing device serves multiple functions: storing cement powder, storing monomer liquid, mixing the components, and dispensing the bone cement dough. This multi-functionality is achieved through the feedthrough structure that integrates storage compartments and mixing interface, thereby simplifying the overall handling procedure while maintaining adaptability.
4Ease of operation
If separate extrusion devices are used for dispensing bone cement dough, then dispensing control is achieved, but additional equipment and sterilization requirements increase complexity and costs
Solution Approach 1:
The dispensing function is merged with the mixing device by incorporating a dispensing plunger that can be pushed through the feedthrough structure. This integration eliminates the need for separate extrusion devices, maintaining dispensing control while reducing the number of devices and simplifying sterilization procedures.
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 system produces a homogeneous bone cement dough with minimal air inclusions, simplifies the handling process, reduces user error, and allows for easy sterilization, making it more efficient and cost-effective for surgical applications.
Implementation Method 1
The conveying plunger is pushable in the internal space of the cartridge in the direction of the dispensing plunger... pushing the monomer liquid from the second hollow space into the cement powder in the first hollow space
Implementation Method 2
the fluid opening is closable with the closure means when the conveying plunger is being pushed in the direction of the dispensing opening
Data Source
AI summary
One embodiment relates to a device for the production of a bone cement dough from a monomer liquid and a cement powder comprising a cartridge with an internal space; a cartridge head with a dispensing opening; a conveying plunger that is arranged in the internal space of the cartridge and is supported in the internal space of the cartridge such that it is pushable in the direction of the dispensing opening; a dispensing plunger between the dispensing opening and the conveying plunger that is supported in the internal space of the cartridge such that it is pushable in the direction of the dispensing opening; a first hollow space, in which the cement powder is arranged; a second hollow space that is bordered by the dispensing plunger and the conveying plunger; a fluid opening that is arranged in the conveying plunger; a feedthrough that connects the first hollow space and the second hollow space to each other, and a closure means that is arranged on a rear side of the dispensing plunger. The closure means projects away from the dispensing plunger and is situated at a distance from the fluid opening. The fluid opening is closable with the closure means. The closure means is mobile in the closed fluid opening such that the fluid opening stays closed, while the conveying plunger is pushable further in the direction of the dispensing plunger.