PMMA Bone Cement Mixing With Septum-Piercing Transfer

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Solution Overview

Problem

Existing prepackaged mixing systems for PMMA bone cement face challenges such as uncontrolled mixing, conduit blockage due to swelling and sticking, and the need for safe and reproducible transfer of monomer liquid, which can lead to air inclusions affecting mechanical properties.

Innovation Solution

A device comprising a base part with a container for monomer liquid and a cartridge for PMMA bone cement powder, featuring a hollow mandrel and a self-sealing septum for controlled mixing, allowing separate storage and reliable transfer of monomer liquid without conduit blockage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If monomer liquid is transferred through a conduit in prepackaged mixing systems, then mixing can be achieved, but the conduit may become blocked due to swelling and sticking of cement powder

Engineering Contradiction:

Improvemonomer liquid transferVSAvoidconduit blockage prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system divides the mixing components into separate sealed cartridges (monomer cartridge and powder cartridge) that are connected only at the moment of use. This segmentation prevents premature contact and swelling of powder in the conduit, eliminating the blockage risk while maintaining reliable transfer when needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A porous barrier or filter is introduced as an intermediary element between the monomer liquid and powder components. This intermediary allows controlled interaction (swelling and mixing) only at the designated mixing chamber, preventing powder from migrating into and blocking the monomer transfer conduit while still enabling the necessary chemical reaction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If manual mixing with spatulas is used, then simple mixing is achieved, but air bubbles are included in the bone cement paste

Engineering Contradiction:

Improvemixing simplicityVSAvoidair inclusions

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The manual mechanical mixing process is replaced with a controlled mixing chamber design that uses pressure differential (vacuum or pressure transfer) to move monomer liquid through the powder. This substitution eliminates the need for manual spatula mixing while simultaneously preventing air bubble inclusion through controlled fluid dynamics and optional vacuum degassing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If separate compartments are used for powder and monomer, then uncontrolled mixing during storage is prevented, but safe and reproducible transfer is challenging

Engineering Contradiction:

Improvecomponent separation during storageVSAvoidtransfer reproducibility

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The cartridge connection system is designed with universal features including alignment guides, sealing mechanisms, and controlled transfer pathways that work consistently for each use. This multi-functional design ensures both stable separation during storage and reproducible transfer during mixing, achieving both goals through a unified connection architecture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system performs preliminary actions by pre-sealing both monomer and powder in sterile, calibrated cartridges with integrated sealing mechanisms. The connection system is designed to automatically ensure proper alignment and sealing before transfer begins, eliminating variability and ensuring reproducible results without requiring manual intervention during the critical transfer phase.

Inventive Principle:

Principle #10Preliminary action

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

Ensures complete transfer of monomer liquid into the powder component, preventing conduit blockage and air inclusions, resulting in a reliable and safe production of PMMA bone cement dough.

Implementation Method 1

a puncture connection between the base part and the cartridge is formed by piercing the septum with the hollow mandrel

Methodology Applied

Scientific EffectPuncture connection:

Implementation Method 2

a self-sealing puncture connection

Methodology Applied

Scientific EffectSelf-sealing:

Data Source

PatentEP4616935A1Bone cement mixing system with a puncture connection

Publication Date: 2025.09.17 HERAEUS MEDICAL GMBH

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AI summary

The present invention relates to a device for producing bone cement, comprising a base part (100) which has a container (101) for holding a monomer liquid (102), a bottom part (103) with a collection area (104), and a hollow mandrel (105) with a tip (106), and a cartridge (200) for holding a PMMA bone cement powder, wherein the cartridge has a septum (202) which delimits the cartridge to the outside, wherein the device is designed and configured to form a fluid-conducting connection between the base part and the cartridge by piercing the septum with the hollow mandrel in order to transfer a monomer liquid from the collection area into the cartridge.