Apparatus and method for mixing and dispensing bone cement

A method for mixing bone cement, said method comprising the steps of.

• placing bone cement components in a cartridge, the cartridge including a first cylinder slidably disposed within a second cylinder, the first cylinder initially being extended from the second cylinder;
• installing a cap on a proximal end of the second cylinder and connecting a vacuum pump to a vacuum port on the cap, whereby vacuum can be drawn within the cartridge;
• drawing vacuum in the cartridge by operating the vacuum pump and thereby causing the first cylinder to be drawn into the second cylinder;
• halting the operation of the vacuum pump when the pressure within the cartridge reaches a desired level, thereby stopping the first cylinder from being further drawn into the second cylinder;
• and
• then mixing the bone cement components within the cartridge under the vacuum created within the cartridge.

An apparatus for mixing and delivering bone cement, said apparatus comprising:

• a cylinder;
• a cap on one end of said cylinder and defining an outlet port therethrough;
• and
• a piston plug disposed in said cylinder for axial movement in said cylinder toward said cap to expel the bone cement in said cylinder through said outlet port;
• said piston plug having a tapered protrusion thereon which is oriented toward said cap, wherein said cap includes a recess corresponding in shape to said protrusion, said recess matingly receiving said protrusion when said plug is moved axially toward said cap, whereby the bone cement is squeezed from said cylinder;
• an agitator for mixing the bone cement, said agitator comprising a shaft extending through said outlet port, a first end of said shaft disposed within said cylinder;
• and
• a plurality of paddles connected to said first end of said shaft and extending radially therefrom for mixing the bone cement, said paddles forming a shape which corresponds to said piston plug and said cap, whereby said cap and said piston plug matingly receive said paddles therebetween when said piston plug is moved axially toward said cap.