Bone Cement Piston Closure Pin for Dead Volume Control
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Solution Overview
Problem
Existing bone cement mixing devices face challenges such as air inclusion, inconsistent mixing ratios, and complex operation, leading to potential errors and the need for costly training to avoid user mistakes, while also being costly and difficult to sterilize in a surgical setting.
Innovation Solution
A device with a cylindrical cartridge containing a discharge piston and a closure pin that seals the discharge opening, allowing for a dead volume to retain any incompletely mixed bone cement, ensuring a homogeneous dough is produced and preventing monomer liquid escape, using a simple manually driven squeezing mechanism for mixing and dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional mixing devices are used, then air inclusions occur in the bone cement mixture, but the mixing process becomes complex and requires costly training
Solution Approach 1:
The device separates the mixing chamber into distinct zones: a monomer reservoir, a powder reservoir, and a mixing chamber with integrated vacuum capability. This segmentation allows independent control of each component and the mixing process, eliminating air inclusions while maintaining simple operation through dedicated functions for each zone.
Solution Approach 2:
An integrated vacuum system acts as an intermediary mechanism that simultaneously removes air from the mixing chamber and facilitates complete mixing of monomer and powder. This intermediary function resolves the contradiction by providing a single mechanism that addresses both air elimination and mixing quality without requiring complex separate systems.
2Manufacturing precision
If fully prepacked mixing devices are used, then sterilization becomes costly and difficult, but the mixing ratio consistency improves
Solution Approach 1:
The device employs local quality differentiation by making the mixing chamber and delivery system sterilizable while keeping the prepacked powder and monomer components in separate, sterile containers until use. This allows the critical mixing and delivery areas to be sterilized autonomously without requiring sterilization of entire prepacked units, maintaining mixing precision while simplifying sterilization logistics.
Solution Approach 2:
The powder and monomer are prepacked in sterile containers before use, eliminating the need for sterilization of these components during surgery. Only the mixing chamber and delivery system require sterilization, which is a simpler, faster process. This preliminary packaging action resolves the contradiction by shifting sterilization requirements to only the necessary components.
3Ease of operation
If manual dispensing devices are used, then operation simplicity increases, but the risk of user errors increases
Solution Approach 1:
The device incorporates visual indicators that provide real-time feedback on the mixing process: color changes indicate when the bone cement has reached optimal consistency, and visual markers show the progression of mixing. This feedback mechanism guides users through the process, maintaining simple operation while eliminating errors by providing clear, objective cues for each stage of mixing and dispensing.
Solution Approach 2:
The device performs self-regulation of the mixing process through integrated timing mechanisms and automatic stopping features that prevent over-mixing. The system autonomously controls critical parameters such as mixing duration and component ratios, allowing simple manual operation while ensuring consistent, error-free results through built-in self-correction mechanisms.
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 ensures a consistent bone cement dough is produced and applied throughout the process, simplifies user operation, reduces the risk of errors, and allows for cost-effective, sterile, and easy-to-use bone cement application without the need for complex assembly or sterilization of non-ferrous metals.
Implementation Method 1
a closure means is arranged on the front side of the discharge piston facing the discharge opening, which closure means closes the discharge opening when the discharge piston is pressed against the front side of the interior of the cartridge
Implementation Method 2
the closure means is a pin projecting from the front of the dispensing piston, which can be at least partially inserted into the dispensing opening to close the dispensing opening, wherein the pin blocks further movement of the dispensing piston towards the front of the cartridge
Data Source
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AI summary
The invention relates to a device for producing a bone cement paste (54) from a monomer liquid (4) and a cement powder (5) as starting components of the bone cement paste (54) and for dispensing the mixed bone cement paste (54), the device comprising a cartridge (1) with a cylindrical interior, wherein the interior of the cartridge (1) is closed at the front except for a discharge opening for dispensing the bone cement paste (54), wherein a discharge piston (7) that can be pushed towards the discharge opening is arranged in the interior of the cartridge (1), and wherein the cement powder (5) is arranged in the interior of the cartridge (1) between the discharge opening and the discharge piston (7), wherein a closing means (9) is arranged on the front of the discharge piston (7) facing the discharge opening, which closes the discharge opening when the discharge piston (7) is pushed against the front of the interior of the cartridge. (1) is pressedwherein the sealing means (9) and/or an additional spacer blocks further movement of the dispensing piston (7) towards the front of the cartridge (1), so that the dispensing piston (7) is at least partially spaced away from the front of the interior of the cartridge (1) and a dead volume remains in the interior of the cartridge (1) when the dispensing piston (7) is pressed against the front of the interior of the cartridge (1). The invention also relates to a method for producing a bone cement paste (54) using such a device.