Telescoping plunger assembly

This disclosure claims the benefit of priority of U.S. Provisional Patent Application No. 60/691,859, filed Jun. 17, 2005, which is incorporated herein by reference.

The present application relates to plunger assemblies and, more particularly, to telescoping plunger assemblies.

Syringe assemblies have been used to deliver bone filler to patients. Typically, syringe assemblies include a syringe barrel with an opening at one end for delivering the bone filler. A plunger assembly is usually adapted to pass through the syringe barrel and push the bone filler through that opening.

In order to deliver a greater amount of bone filler, from a syringe assembly, typically, a larger syringe barrel is provided (i.e., a barrel that is larger in diameter and/or longer).

The present disclosure relates to telescoping plunger assemblies for a material delivery device. The material delivery device typically includes a first compartment to temporarily store the material and a syringe barrel coupled to the first compartment. A plunger assembly is adapted to extend telescopically from a compacted state substantially contained within a first compartment of the device through the syringe barrel to dispense material.

In some implementations, the material delivery device is a bone filler mixing and delivery device. Examples of bone cement mixing and delivery devices are disclosed in U.S. patent application Ser. Nos. 10/438,471, 10/637,908 and 11/252,515, which are incorporated by reference. A person of ordinary skill would understand that the techniques and devices disclosed herein could be readily adapted to any type of material delivery device.

In one aspect, a bone filler mixing and delivery device includes a mixing section with a mixing element adapted to mix components to form bone filler. A syringe barrel is coupled to the mixing section and has an opening through which the bone filler can be dispensed. A controllable portal (also referred to as an access portal) is provided that can be manipulated to open a flow path between the mixing section and the syringe barrel. A plunger assembly is adapted to extend telescopically in an axial direction through the syringe barrel to dispense the bone filler through the opening. In certain implementations, the plunger assembly is adapted to telescopically retract to a position completely contained within the mixing section.

In some implementations, the telescoping plunger assembly includes a drive shaft that can be rotated about an axis, a lead screw threaded to the drive shaft and a plunger shaft threaded to the lead screw. Typically, in those implementations, the drive shaft is restricted from moving in an axial direction and the plunger shaft is restricted from moving in a rotational direction.

According to some implementations, rotation of the drive shaft causes relative rotation between the lead screw and at least one of either the plunger shaft or the drive shaft. Typically, in those implementations, the relative rotation causes the plunger shaft to move axially through the bone filler mixing and delivery device.

Certain implementations include a support sleeve adapted to provide mechanical support to the plunger shaft. In those implementations, the plunger shaft can be coupled to the support sleeve in a manner that allows relative motion between the plunger shaft and the support sleeve in an axial direction, but restricts relative motion between the plunger shaft and the support sleeve in a rotational direction. In some implementations, a longitudinal slot is formed in the plunger shaft and a pin extends from the support sleeve to engage the longitudinal slot and prevent the plunger shaft from rotating about the axis. The pin may be adapted to move longitudinally through the longitudinal slot as the plunger shaft is moved axially through the bone filler mixing and delivery device.

In another aspect, a material delivery device includes a syringe barrel with a portal for loading material into it and an opening through which the material can be dispensed. A plunger assembly is adapted to extend telescopically through the syringe barrel to dispense the material through the opening. In some implementations, the plunger assembly is adapted to retract telescopically to a position completely outside of the syringe barrel.

In some implementations, the material delivery device has a drive shaft that can be rotated about an axis, a lead screw that is threaded to the drive shaft and a plunger shaft that is threaded to the lead screw. In some of those implementations, the drive shaft is restricted from moving in an axial direction and the plunger shaft is restricted from moving in a rotational direction. In some of those implementations, rotation of the drive shaft causes relative rotation between the lead screw and at least one of either the plunger shaft or the drive shaft, and the relative rotation causes the plunger shaft to move axially through the material delivery device.

According to some implementations, a support sleeve is adapted to provide mechanical support to the plunger shaft. In those implementations, the plunger shaft is coupled to the support sleeve in a manner that allows relative motion between the plunger shaft and the support sleeve in an axial direction, but restricts relative motion between the plunger shaft and the support sleeve in a rotational direction.

In certain implementations, a longitudinal slot is formed in the plunger shaft and the material delivery device includes a pin that extends from the support sleeve to engage the longitudinal slot and prevent the plunger shaft from rotating about the axis. In such implementations, the pin is adapted to move longitudinally through the longitudinal slot as the plunger shaft is moved axially through the bone filler mixing and delivery device.

Some implementations include a support sleeve that is movable in an axial direction, where the pin is adapted to drag the sleeve in the axial direction with the plunger shaft as the plunger shaft moves beyond an axial position where the pin reaches an end of the longitudinal slot.

Particular implementations include a first section that is coupled to the syringe barrel. In those implementations, the first section is adapted to store the material and the plunger assembly is adapted to extend from the first section through the syringe barrel.

In some implementations, one or more of the following advantages may be present. By implementing a telescoping plunger assembly, material delivery devices, such as a bone filler mixing and delivery devices, may be made more compact than would be otherwise possible. Additionally, such devices might be made easier to handle, which can be particularly important in tight quarters, such as in an operating room.