Bone Cement Applicator with Closable Gas Supply Opening
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Solution Overview
Problem
Existing bone cement mixing systems are complex, expensive, and difficult to sterilize, with internal spaces requiring disassembly, which can compromise sterilization and increase labor and complexity, especially when dealing with polymethylmethacrylate (PMMA) bone cement for vertebral augmentation and pedicle screw filling.
Innovation Solution
A full-prepacked, closed system device for mixing PMMA bone cement using separate compartments for cement powder and monomer liquid, featuring a cartridge with a cylindrical design, a screwable monomer receptacle, and a plunger with a gas-permeable passage to prevent monomer vapor escape, allowing for easy handling and sterilization with ethylene oxide without exposing the user to monomers, and enabling efficient mixing and extrusion of the bone cement dough without external mixers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closed full-prepacked mixing device is used to prevent monomer vapor escape and ensure sterility, then user safety and sterility are improved, but device complexity and difficulty of sterilization increase
Solution Approach 1:
The device is divided into separate compartments: a cartridge containing cement powder and a monomer receptacle containing monomer liquid. This segmentation allows each component to be sterilized independently and simplifies the overall sterilization process while maintaining a closed system that prevents monomer vapor escape.
Solution Approach 2:
The monomer receptacle is inserted into the cartridge assembly, with the plunger extending into the cartridge. This nested configuration allows the monomer to be transferred into the cartridge through the plunger's gas-permeable passage while maintaining a compact, closed system that is easier to sterilize as a single unit.
2Object-affected harmful factors
If the monomer receptacle is made gas-tight to prevent monomer vapor escape, then user safety is improved, but the ability to sterilize the internal space with ethylene oxide gas deteriorates
Solution Approach 1:
The monomer receptacle features a dynamic gas supply opening that can be opened during sterilization and closed during operation. The opening facility allows ethylene oxide gas to penetrate the internal space when needed, then seals to prevent monomer vapor escape during use, providing both sterilization accessibility and vapor containment.
Solution Approach 2:
The gas supply opening acts as an intermediary element that temporarily connects the internal space to the external environment during sterilization, then seals to isolate the system during operation. This mediator allows the system to fulfill both contradictory requirements at different stages.
3Manufacturing precision
If separate compartments are used for cement powder and monomer liquid, then mixing precision is improved, but device complexity increases
Solution Approach 1:
The device combines separate compartments for cement powder and monomer liquid into a single integrated cartridge assembly. The monomer receptacle with plunger merges the functions of monomer storage, transfer, and mixing initiation into one component, achieving precise mixing control without proportionally increasing device complexity.
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 device simplifies the mixing and application of low-viscosity PMMA bone cement, reducing the risk of air bubble formation, allowing for safe, efficient, and hygienic use in vertebral augmentation and pedicle screw filling, while maintaining the sterility of the device and minimizing user exposure to monomers.
Implementation Method 1
at least one gas supply opening (7) through which a gas can be aspirated from the inside of the device and through which a sterilizing gas such as ethylene oxide can be delivered for sterilization of the inside of the device
Implementation Method 2
a plunger with a gas-permeable passage to prevent monomer vapor escape
Data Source
AI summary
A device for producing a bone cement dough from a monomer liquid and a cement powder and dispensing the bone cement dough. The device includes a cartridge holding the cement powder in an internal space. A monomer receptacle screws onto the cartridge, forms a chamber, and has a plunger with a passage that is permeable to gases and the monomer liquid but is impermeable to the cement powder and that connects the internal space to the chamber. The plunger tightly closes the internal space with the exception of the passage. A gas supply opening is arranged in the wall of the monomer receptacle. A monomer liquid container holds the monomer liquid and is located in the chamber. An opening facility opens the container, and closes the gas supply opening before opening the container. Also provided is a method for producing and dispensing the bone cement dough.