Patent Application
20060133193
The present invention relates to the sealed transfer of a therapeutic material from one device to another. More particularly, the invention relates to an assembly or port which optimizes the transfer of a viscous material from one device to another. The invention is particularly suitable for transferring the material from a mixing device to an injection device.
The introduction of viscous materials to an implantation site within a patient to affect one or more therapeutic goals is well known. Material ranging from typical fluids or solutions to non-Newtonian fluids, pastes, gels and the like has been used for one purpose or another in the medical arts.
A commonly injectable viscous material is bone cement. Bone cement is often used to affix a prosthesis to a bone or joint structure. Hip and knee joints are the most common examples of such prosthetic devices. Another common use of bone cement is for repairing or mending bone fractures or shattered bone or for supplementing a weakened bone structure, such as in the case of vertebroplasty. Bone cement may also be used for cosmetic or dental surgery. Moreover, bone cement may be used as a drug delivery or release system, whereby the bone cement is mixed with antibiotics or other desired drugs and applied to a specific surgical site such that the drugs leach out and are delivered directly to the surgical site. U.S. Pat. No. 6,383,190 describes a high pressure applicator for delivering a flowable implant material to a target tissue.
Bone cements are typically formed by mixing a polymer powder and a liquid monomer, such as polymethyl methacrylate (PMMA) or methyl methacrylate. In order to activate the bone cement, the components must be combined or mixed.
The two components forming the cement are first combined in a mixing container such as a bowl and then the material is transferred to a separate dispensing or injection apparatus. Conventionally, the cement is poured or spooned from the mixing device to the dispensing device. More recently, systems have been developed to provide for the transfer of the cement from the mixing container into the dispensing device. Examples of delivery or dispensing systems are found in U.S. Pat. No. 6,783,515, and U.S. Patent Application Serial No. 2003/0012080, each of which is incorporated by reference herein.
A shortcoming of the above described procedures is the escape of gaseous fumes of the bone cement during mixing and transfer from the mixing container to the injection system. This problem arises because the bone cement emits vapors as it is mixed. These vapors are toxic. Surgeons performing these types of surgical procedures desire to minimize their exposure to the toxic gaseous fumes. Additionally, air bubbles may be trapped in the cement during mixing. The air bubbles may compromise the quality of the bone cement to treat or repair the target bone. Also, exposure to the air or atmosphere may degrade or slow the curing time.
Accordingly, there exists a need for an improved mechanism and system for directly transferring viscous materials from one chamber to another in a completely sealed, airtight manner.
The system of the present invention includes apparatus and methods adapted to meet such needs as well as provide other advantages readily apparent to those with skill in the art.
The present invention is a mechanism and improved system and method for the transfer of material from one chamber or device to another chamber or device, wherein the mechanism may be a discrete component or part of an integrated system. The invention is particularly suitable where the material is viscous and/or where it is preferential to maintain the material in a sealed environment where fumes from the material are unable to escape into the ambient air and the ambient air is unable to enter into the sealed environment.
In one variation of the present invention, a system is configured for mixing and injecting a viscous material, where the system includes a sealed mixing chamber for mixing two or more ingredients of the viscous material, a sealed injection chamber, and a material transfer mechanism for transferring the viscous material from the mixing chamber to the injection chamber in a sealed manner, wherein the material transfer mechanism is configured to prevent the transfer of the viscous material from the injection chamber back into the mixing chamber even if the injection pressures are high. The material transfer mechanism may include a one-way valve or the like.
The methods of the present invention include a method for preparing a flowable hardenable material for injection into the body, where the method specifically includes providing a first sealed chamber containing the material, providing a second sealed chamber configured to receive the material from the first sealed chamber, transferring the material from the first chamber to the second chamber in a sealed manner, and injecting the material contained in the second chamber into a target site within the body. Transferring the material involves sealingly engaging the first chamber with the second chamber, and injecting the material may include preventing the transfer of the material from the second chamber back into the first chamber. The type of material mixed in the first chamber may vary and it may be bioabsorbable, osteointegrable, or another type of material or combination of materials. An example of a material to be prepared or mixed in the first (or mixing) chamber is a PMMA bone cement. PMMA may be supplied in the mixing chamber in a powder and separate liquid monomer. The two ingredients are combined in the mixing chamber to form a flowable doughy cement material that is directly transferred into the injection chamber in accordance with the present invention.
In one application of the invention, a vertebroplasty method is provided which includes providing a sealed mixing chamber containing a bone cement material, and a sealed injection chamber configured to receive a material from the mixing chamber, mixing ingredients of a bone cement material in the sealed mixing chamber, transferring the bone cement material from the mixing chamber to the injection chamber in a sealed manner, and injecting the bone cement material contained within the injection chamber into at least one vertebra.
These and other objects, advantages, and features of the invention will become apparent to those persons skilled in the art upon reading the details of the invention as more fully described below.
The invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings may not be to-scale, and the dimensions of the various features may be arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures:
Before the present invention is described, it is to be understood that this invention is not limited to particular applications and embodiments described, and as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.
Although any method or materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. While the present invention is especially useful in injecting with bone cement, such as PMMA, and the invention is described with reference to such application, such description is not intended to be limiting and may be used with various injectable materials for various applications.
Referring now to the drawings, and to
Extending substantially axially with distal portion 10 is a material transfer mechanism or material entry port 14 configured for coupling with a mixing device or chamber (not shown). Extending substantially transverse to the longitudinal axis of filling chamber 4 and proximally of material entry port is a material exit port 12 through which the injectable material exits the filling chamber 4 into a needle 13 or delivery conduit 15 upon being driven therefrom. As such, the axis of ports 12 and 14 are substantially transverse to each other but may be otherwise positioned. A handle 16 extends from filling chamber 4, preferably opposite exit port 12 for optimally directing and stabilizing system 2 during the filling and injection procedures.
Another injection system 30 having a detachably coupled mixing device 40 is shown in
Referring to
The connector assembly is shut off when stem head 62 is drawn into the anchor seat 66. The stem head is snugly drawn into the anchor seat by rotating actuator or knob 70. As shown in
The mixing cartridge 40 preferably contains all components necessary to form a flowable hardenable bone cement. For example, the cartridge may contain an enclosed ampoule of monomer, and a powder that reacts or polymerizes when combined with the monomer. The contents of the cartridge may be activated and expelled by a plunger (not shown) that forces the combined mixture out of the cartridge and into the injector device 30 via connector assembly 50. An example of a known mixing cartridge is disclosed in U.S. Pat. No. 5,435,645 to Faccioli et al, which is incorporated by reference in its entirety.
Additional materials may be added or contained within the cartridge as desired. For example, radiopaque tracer particles may be added to facilitate visualization and/or medicines may be added. Tracer particles are described in U.S. Pat. No. 6,309,420. Preferably, the mixing cartridge 34 is fully self-contained such that no materials need to be added by the doctor during a surgical procedure. To this end, the cartridge is prepackaged and the surgeon simply attaches the self enclosed cartridge to the injector by, for example, screwing the threads 42 of the cartridge to the connector assembly 50. The cartridge 40 may thus be detachably (or non detachably) coupled to the injector system.
The connector assembly may be fabricated from a wide variety of materials. An exemplary material may be injection molded plastics. An example of a material is nylon. The connector assembly may be provided permanently attached to (or integrated with) the injector device or it may be separately fastened to the injector assembly with, for example, threads 68 that match with threads in a port of the injector assembly.
The connector assembly also ensures that no back flow of viscous material from the filling chamber will flow into the mixing chamber because of the shape of the stem head 62. The stem head 62 shown in
As shown in
Although the dimensions of the present invention may vary widely, an exemplary lumen diameter may be from about 0.2 to 0.4 inches. The diameter of the filling chamber may be from about 0.5 to 0.8 inches. The valve stem is preferably long enough to accommodate the stem travel plus a few threads of travel. For example, the stem may range from 0.5 to 1 inches long. Additionally, knob 70 preferably has a sufficient number of threads to accommodate both the mixing cartridge threads and the travel of the valve stem. The above mentioned dimensions are intended as exemplary dimensions and unless specifically recited in the claims are in no way intended to limit the invention.
Another variation of the present invention is illustrated in
A wall 104 separating chambers 82 and 84 provides a passageway or port 106 through which a plug member 102 is positioned. Port 106 may be internally threaded in applications where a removable mixing chamber is to be received and engaged within chamber 84. As best illustrated in
In use, a plunger or piston mechanism (not shown) is used to drive or distally advance the injectable material from mixer chamber or material reservoir 84 in the direction of arrow 110 of
During a procedure to dispense bone cement, for example, the plunger or piston is urged downward, dispensing bone cement from the exit port 130. As the plunger is urged downward it covers entry port 136, preventing back flow into mixing chamber. As such, a lightly secured cap 136, rather than the more tightly secured valve and plug mechanisms described above, need be used to prevent back flow of material through filling port 134. The port 136 is not exposed to the potentially high pressure of injection because the port shall be behind (or upstream) the actuating plunger.
Adapter 148 is shown having a knob 149, a body 150, and a valve stem 152 movably positioned within body. Knob 149 includes an aperture 200 and a thread feature 151. Threaded feature 151 of knob 149 is intended to accommodate and interlock with a corresponding threaded feature on the mixing device 150. The threaded feature 151 preferably has a pitch and thread profile consistent with medical Luers. As such this would make it compatible with fluid connectors of most medical devices. However, the ports and openings may be provided with other features to fluidly connect with one another.
The valve stem 152 floats in an axial direct and is not allowed to rotate. Rotation of the stem may be prevented any number of ways including providing a guide, flat region, or groove on the stem that slidably mates with an associated feature of the body 150. Referring to
Port body 150 is shown having female 153 and male 154 Luer connecting ports. These ports are intended to accommodate the corresponding ports on an injector 140 and a connecting tube 152. Luer-type connectors are preferred because it is a common type of fluid connector in the medical device industry. The body 150 also may be sealed with a cap or plug 202. Such a plug may be glued in place or otherwise secured in place after the adapter is assembled. The adapter may be fabricated from materials similar to the devices described above. For example, the device may be comprised of Nylon.
In operation or use, the adapter is connected to an injection device 140. A mixing device may then be connected to the adapter as described above. A flexible conduit or delivery tube may be connected to the adapter as well.
The knob 149 is then rotated to displace or urge the stem downward into the body 150. The mixing cartridge may then be actuated and the flowable material may be injected from the mixing device through the adapter into the injection device. Of course, some mixed material may flow into the flexible conduit 152. However, a majority of the cement should flow through the path of least resistance and thus, into injection chamber 147.
Once the mixed flowable material has filled the injection device, the knob 149 is rotated to seat the valve stem in the valve body closing off the flow pathway to the mixing device. Material may now only flow from the injection device, through the adapter, into the conduit 152. As such, the present adapter assembly may sealingly join a self-contained mixing device (or cartridge) to a separate injection device regardless of whether either device was intended to be joined with one another. The adapter 148 may thus convert an injector into an integrated mixing and injection system.
As mentioned above, the systems, devices and material transfer mechanisms of the present invention are particularly useful for the transfer of bone cement from one chamber to another, for example, in the context of vertebroplasty applications. As such, the present invention provides a method of performing an orthopedic procedure which includes the mixing of materials, such as a polymer powder and a liquid monomer to form polymethyl methacrylate (PMMA), within a mixing device or chamber, preferably in a sealed device or chamber such that no fumes from the material are released into the environment. The method further includes transferring the mixture from the self-enclosed mixing device or chamber to an injection device or chamber, also without the release of fumes, and then injecting the material to a target site within the body.
The present invention may also include those concomitant parts or elements useable with the subject systems and devices in delivering material to a site within a patient. Such elements may include a delivery hose, a cannula (alone or in combination with one or more stylets) and the injectable material, e.g., the bone cement. Together, these elements may form part of the inventive kit or system to be used in a procedure or method as variously described herein. A plurality of such elements and devices may be provided where the devices have the same or varying sizes. The kits may further include instructions for mixing implantable material, transferring the implantable material from a mixing device or chamber to an injection device or chamber, and injecting the implantable material into a target site within the body.
The preceding merely illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the present invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of present invention is embodied by the appended claims.
