Patent Application
20120265209
For certain medical procedures, it is desirable or necessary to mix components of a medical preparation together immediately prior to use. It is also desirable to mix components in single use batches, to assure consistency in the delivery of the combined components. Compositions such as bone fillers, bone cements, medical adhesives, dental adhesives, and the like, often rely on mixing syringes combining components and subsequently delivering the combined components to the desired anatomical location.
Kyphoplasty is one example of a procedure that uses mixed compositions to treat vertebral compression fractures and restore vertebral height. Using a minimally invasive approach, one or more compliant balloons is inserted inside a fractured vertebral body. The balloons are inflated such that cancellous bone from the vertebral body is pushed toward the cortical wall, and the resulting cavity is filled with a mixed composition such as polymethylmethacrylate (PMMA). Improved mixing tools and methods are needed for preparing mixed compositions used in kyphoplasty and other medical procedures.
Further aspects, forms, embodiments, objects, features, benefits, and advantages of the present invention shall become apparent from the detailed drawings and descriptions provided herein.
In one embodiment, a mixing apparatus comprises a cylindrical body extending between proximal and distal ends. The cylindrical body has a hollow interior and an outlet at the distal end. The mixing apparatus also includes a plunger having an elongated shaft with a distal end, a first mixing plate with a first plurality of holes extending therethrough, and a second mixing plate with a second plurality of holes extending therethrough. The first and second mixing plates have a first relative position, adapted for mixing, in which the first and second plurality of holes are aligned. The mixing plates have a second relative position, adapted for material dispensing, in which the first plurality of holes are blocked by the second mixing plate.
In another embodiment, a method for mixing a medical composition comprises depositing first and second components of the medical composition into a cylindrical body having proximal and distal ends and a hollow interior. The method further includes inserting a plunger into the hollow interior. The plunger includes an elongated shaft with a distal end, a first mixing plate with a first plurality of holes extending therethrough, and a second mixing plate with a second plurality of holes extending therethrough. The method further includes positioning the first plurality of holes in alignment with the second plurality of holes and moving the plunger with an axial reciprocating motion within the cylindrical body to cause portions of the first and second components to move through the aligned first and second plurality of holes.
In another embodiment, a bone cement mixer includes a syringe extending between proximal and distal ends. The syringe has a hollow interior and outlet at the distal end. The mixer also includes a mixing mechanism sized for axial and rotational movement with the syringe. The mixing mechanism including a pair of mixing plates rotatable relative to each other to move between a first position in which a plurality of passages through the mixing plates are aligned to allow flowable bone cement components to pass through the pair of mixing plates and a second position in which the plurality of passages are misaligned to prevent flowable bone cement components from passing through the pair of mixing plates.
a is a top view of a portion of a mixing apparatus in a first configuration according to another embodiment of this disclosure.
b is a cross-sectional view of the portion of the mixing apparatus of
a is a top view of the portion of the mixing apparatus of
b is a cross-sectional view of the portion of the mixing apparatus of
The present disclosure relates generally to the field of medical composition mixing devices and methods, and more particularly to systems and methods for mixing medical compositions using a convertible mixing and plunging device. For the purposes of promoting an understanding of the principles of the invention, reference will now be made to embodiments or examples illustrated in the drawings, and specific language will be used to describe these examples. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alteration and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein, are contemplated as would normally occur to one skilled in the art to which the disclosure relates.
Referring to
The mixing apparatus 10 further include a plunger 26 that functions to both mix components in the interior chamber 17 and to evacuate the mixed material from the interior chamber, as will described in greater detail below. The plunger 26 has a proximal end 28 and a distal end 30. The proximal end 28 includes a handle 30 for controlling the motion of the plunger 26. The plunger 26 includes an elongated shaft 32 extending between the proximal 28 and distal 30 ends along a system axis 31. The shaft 32 may be tubular or solid and may be formed from metals, plastics, ceramics or other materials that provide sufficient rigidity.
A pair of mixing plates 34, 36 are coupled to and extend perpendicularly to the system axis 31 from the distal end of the shaft 32. The mixing plates 34, 36 are circular and have a diameter sized slightly smaller than the inner diameter of the chamber 17 to allow the plates to slide axially within the chamber 17 along the wall 18 of the cylindrical body 12. The plates may be formed from metals, plastics, ceramics, or other materials. Optionally, a sliding seal may extend about the outer perimeter of one or both mixing plates so that the flow of material between the wall of the chamber and the mixing plates is minimized. Alternatively, the mixing plates may have a diameter sufficiently smaller than the inner diameter of the chamber so that material can flow between the edges of the plates and the wall of the chamber.
As shown in
As shown in
The mixing plates 34, 36 can also be arranged in a dispensing configuration. In the dispensing configuration, mixing plate 36 is rotated about the system axis 31 relative to plate 34. As shown in
As shown in
The mixing apparatus 10 may be used for mixing and dispensing medical compositions such as bone fillers, bone cements, medical adhesives, dental adhesives, and the like. The medical compositions may be formed of multiple components, including liquids, powders, solids, pasty materials, and viscous materials. Commonly, the mixing apparatus may be used to mix a two-part composition comprising a liquid and a power component. Powder components may include autograft tissue, allograft tissue, demineralized bone matrix, calcium phosphate compositions, or polymer cement components. Liquid components may include a buffered aqueous solution, glycerol, or a monomer cement component. The mixing apparatus 10 may be particularly suitable for use with PMMA compositions such as KYPHON HV-R® Bone Cement or compositions that contain PMMA and hydroxyapatite (HA) such as KYPHON ActivOs™10 bone cement offered by Medtronic, Inc. of Minneapolis, Minn. It is understood that the examples provided are not limiting and the mixing apparatus of this disclosure may be used to combine components for any medical compositions.
Methods of using the mixing apparatus 10 will now be described. The mixing apparatus is initially arranged in a mixing configuration. To prevent the flow of material from the distal outlet 24, the outlet is blocked by a cap, a mixing stand, a frangible membrane or other occluding devices known in the art. Two or more components of a chosen medical composition 54 are deposited in the interior chamber 17 of the cylindrical body 12. The components may be added separately or may be premixed and introduced to the chamber 17 together in a nonhomogenous mixture. The mixing plates are arranged as shown in
Referring now to
Referring now to
In the embodiment of
In alternative embodiments, the mixing plates may have a flow hole pattern 74, as shown in
As shown in
While the present invention has been illustrated by the above description of embodiments, and while the embodiments have been described in some detail, it is not the intention of the applicant to restrict or in any way limit the scope of the invention to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general or inventive concept. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.
