Bone Cement Applicator Three-Way Valve Pressure Relief
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Solution Overview
Problem
Conventional bone cement applicators for vertebroplasty face challenges such as high effort required for manual operation, contamination risks, and inefficiencies in mixing and dispensing highly viscous polymethyl methacrylate (PMMA) bone cement, particularly with two-component systems, leading to delayed application and residue issues.
Innovation Solution
A bone cement applicator design featuring a tubular cartridge with a three-way valve and a static mixer, allowing for manual operation with reduced force requirements, immediate mixing and dispensing, and a collection system to prevent contamination, using a single discharge piston to manage both starting components effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional discharge pistons with large diameter (30-40 mm) are used to expel viscous bone cement, then the cement can be discharged, but the manual squeezing force required becomes excessively high (1.5-3.5 kN)
Solution Approach 1:
The patent introduces a pressure generation device that uses pneumatic or hydraulic principles to generate high pressure for expelling the bone cement. Instead of relying on manual squeezing force, a pump system with reservoir, pump chamber, and pressure generation mechanism creates the necessary pressure to discharge the viscous cement through the discharge piston, thereby resolving the contradiction between discharge capability and manual force requirement.
2Loss of time
If two-component bone cement systems are used to eliminate waiting time, then surgical time is saved, but the complexity of mixing and dispensing two separate pastes increases
Solution Approach 1:
The patent combines the storage and dispensing of two separate paste components into a single integrated cartridge system. The first and second cartridges are positioned one behind the other, with a common discharge piston that pushes both components through a mixing chamber simultaneously. This merging approach maintains the time-saving benefit of two-component systems while simplifying the dispensing mechanism by using a single piston instead of two separate actuators.
Solution Approach 2:
The patent introduces a mixing chamber as an intermediary component between the two paste components and the discharge point. This mixing chamber allows the two pastes to mix thoroughly before being dispensed, ensuring proper mixing without requiring complex external mixing equipment. The mixing chamber acts as a mediator that simplifies the overall system while achieving the desired mixing result.
3Ease of operation
If manual squeezing devices are used for bone cement application, then the user has tactile feedback on penetration resistance, but the high viscosity of starting components makes operation extremely difficult
Solution Approach 1:
The patent replaces the manual mechanical squeezing system with an automated pressure generation system. Instead of using manual force applied through a squeezing device, a pump mechanism with pressure generation means automatically generates the high pressure needed to expel the viscous bone cement. This substitution eliminates the need for users to apply excessive force while maintaining precise control over the discharge process.
4Quantity of substance
If elastic components deform during cement discharge, then the cement can be pushed through, but volume contraction causes unintended cement escape and contamination
Solution Approach 1:
The patent addresses the elastic deformation issue by designing the system to accommodate and compensate for elastic expansion and contraction. The pressure generation system maintains consistent pressure to prevent unintended escape, and the overall system design considers the elastic properties of components to prevent contamination during the discharge process.
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
Enables efficient, immediate, and controlled application of bone cement with reduced manual effort, minimizing contamination and residue, and allowing for quick restart of cement flow without repressurization, suitable for vertebroplasty procedures.
Implementation Method 1
a static mixer, allowing for manual operation with reduced force requirements, immediate mixing and dispensing
Implementation Method 2
a three-way valve and a static mixer, allowing for manual operation with reduced force requirements, immediate mixing and dispensing, and a collection system to prevent contamination
Data Source
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AI summary
The invention relates to a bone cement applicator for applying a bone cement paste in the spinal region, the bone cement applicator comprising at least one tubular cartridge (1) with an interior space, wherein the initial components of the bone cement are contained in the interior space of the at least one cartridge (1), at least one dispensing piston for ejecting the initial components from the at least one cartridge (1) through an opening of the at least one cartridge (1), wherein the at least one dispensing piston is movable in the longitudinal direction inside the at least one cartridge (1), a hose (4), an application opening (6) through which the bone cement paste is to be applied, and an externally operable three-way valve (2) which is arranged in the hose (4) or on one side of the hose (4) facing the at least one cartridge (1), wherein the three-way valve (2) is in fluid communication with the opening of the at least one cartridge (1).A collection container (9) for receiving bone cement paste, which is arranged on the three-way valve (2), wherein the three-way valve (2) is constructed and arranged in the bone cement applicator such that in a first position it provides a fluid connection between the application opening (6) and the opening of the at least one cartridge (1) and closes a passage to the collection container (9), and in a second position it provides a fluid connection between the application opening (6) and the collection container (9) and closes a passage to the opening of the at least one cartridge (1). The invention also relates to a method for applying bone cement with such a bone cement applicator.