Monophasic Bone Cement via Segmented Injection Mixing
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Solution Overview
Problem
Current polymer cements used in reconstructive surgery and vertebroplasty require complex manual mixing processes, leading to inhomogeneity, toxicity risks, and mechanical issues such as excessive hardness and fragility, which can result in post-operative complications like bone fractures.
Innovation Solution
A monophasic liquid formulation containing polymers, monomers, and a polymerization activator, which is activated by a thin initiator layer within an injection device, eliminating the need for manual mixing and reducing the risk of toxicity and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual mixing of bi-phasic formulations is used, then the cement can be prepared and injected, but the mixing process creates inhomogeneity and requires complex manual intervention
Solution Approach 1:
The formulation is divided into two separate phases (solid phase with initiator and liquid phase with monomer and activator) that are kept independent during storage and only mixed at the moment of injection, eliminating the need for prolonged manual mixing and ensuring homogeneity
Solution Approach 2:
The system automatically mixes the phases through the injection mechanism itself, where the solid and liquid phases are forced together in the injection needle or catheter, eliminating the need for external manual mixing devices and operations
2Ease of manufacture
If manual mixing is performed, then the cement components are combined, but toxic vapor exposure and inhomogeneity risks increase
Solution Approach 1:
The injection needle or catheter acts as an intermediary device that forces mixing of the two phases during injection, eliminating the need for manual mixing in open air and thereby preventing exposure to toxic vapors while ensuring proper mixing
Solution Approach 2:
The mixing and injection process occurs within a closed system (injection needle/catheter) that isolates the operator from toxic vapors, creating an effectively inert environment regarding toxic exposure
3Strength
If standard bi-phasic cements are used, then prosthesis fixation is achieved, but excessive hardness causes bone fractures
Solution Approach 1:
The formulation parameters are modified by incorporating specific polymer bead sizes, monomer compositions, and radiopacifying fillers that control the setting characteristics and mechanical properties of the cement, achieving optimal balance between strength and flexibility to prevent bone fractures
Solution Approach 2:
The cement is formulated as a composite material combining polymer beads, monomers, radiopacifying fillers, and plasticizers in specific proportions, creating a material with optimized mechanical properties that provides both strength and flexibility
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 solution simplifies the preparation and injection process, enhances stability, and produces cements with optimal mechanical properties for vertebroplasty, reducing the risk of fractures and improving surgical outcomes by providing flexible and compressible cements.
Implementation Method 1
bringing into contact of the liquid monophasic formulation with a thin layer or a film containing a polymerization initiator, deposited on a support element of the device, causes its solubilization
Implementation Method 2
contact between the monomer and the initiator/activator association triggering the start of the polymerization reaction
Data Source
Figure 1A~1C
Figure 2
AI summary
The invention relates to a process for preparing cements used for reparative or reconstructive bone surgery, in particular for fixing prostheses, for bone repair and for vertebroplasty, and obtained from liquid single-phase formulations. It also relates to the cements prepared from these single-phase formulations and to a device for injecting them.