A method for producing a bone cement, wherein the bone cement is produced from a cement powder and a monomer liquid using a device for mixing the bone cement, the device comprising
- a cartridge having a cylindrical interior,
- the cement powder for producing the bone cement,
- the monomer liquid for producing the bone cement, wherein the monomer liquid is contained in a monomer liquid container,
- a cartridge head having a discharge opening for expelling the bone cement, wherein the cartridge head closes off the cylindrical interior of the cartridge at a front side of the cartridge, except for the discharge opening,
- a closure, wherein the closure is permeable to gases and impermeable to powder particles of the cement powder, and wherein the closure is arranged in the discharge opening and is removable from the discharge opening,
- a drive piston, wherein the drive piston is impermeable to gases and the monomer liquid, wherein the drive piston is arranged movable towards the cartridge head in the cylindrical interior of the cartridge,
- a central piston, wherein the central piston is permeable to gases and the monomer liquid and impermeable to the powder particles of the cement powder, wherein the central piston is arranged movably in the cylindrical interior of the cartridge towards the cartridge head and is arranged between the drive piston and the cartridge head, wherein
- the central piston separates the cylindrical interior of the cartridge into a first cavity and a second cavity, wherein the first cavity is delimited on a front side by the cartridge head and the closure, opposite thereto by the central piston, and laterally by an inner wall of the cartridge, and wherein the second cavity is delimited on a front side by the central piston, opposite thereto by the drive piston, and laterally by the inner wall of the cartridge, wherein the cement powder is arranged in the first cavity, and wherein the monomer liquid container is arranged in the second cavity,
- wherein the method comprises the following steps:
- A) moving the drive piston toward the cartridge head,
- B) opening the monomer liquid container or rupturing the monomer liquid container via the movement of the drive piston toward the cartridge head, and thereby releasing the monomer liquid in the second cavity,
- C) expelling residual gases through the central piston, through the cement powder, and through the closure, into the surroundings of the device, by means of the movement of the drive piston,
- D) injecting the monomer liquid through the central piston into the cement powder, via further movement of the drive piston toward the cartridge head,
- E) displacing gases between the powder particles with the inflowing monomer liquid, wherein the gases escape through the closure into the surroundings of the device,
- F) wetting the powder particles of the cement powder, and
- G) depressurizing the second cavity after steps A) to F), wherein the second cavity is depressurized by partially removing the monomer liquid contained in the second cavity.