US20120218851A1 - Motorized bone cement mixing and delivery system with a flexible delivery extension tube and enlarged connector for delivering cement into living tissue - Google Patents

Abstract

A bone cement mixing and delivery system including a mixer, a delivery device, and a flexible extension tube. A connector is attached to a distal end of the flexible tube. The connector includes a housing, a spindle configured with a fitting, and an enlarged knob. The spindle is seated within the housing and is configured to rotate between a closed and open position. In the open position, the spindle allows flow from the delivery device flexible extension tube into a bore of the spindle and into the spindle fitting. A delivery cement cannula is attached to the spindle fitting for allowing cement to travel from the delivery tube into living tissue. The enlarged knob is used to rotate the spindle from an open to a closed state and vice versa.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. patent application Ser. No. 12/961,216, filed 6 Dec. 2010, now U.S. patent Ser. No. ______. application Ser. No. 12/961,216 is a divisional of U.S. patent application Ser. No. 12/652,295, filed 5 Jan. 2010, now U.S. Pat. No. 7,854,543. application Ser. No. 12/652,295 is a continuation of U.S. patent application Ser. No. 12/416,171, filed 1 Apr. 2009, now U.S. Pat. No. 7,658,537. application Ser. No. 12/416,171 is a continuation application of PCT Application No. PCT/US2007/021408, filed 5 Oct. 2007, which claims priority to U.S. Provisional Patent Application Ser. No. 60/828,509, filed 6 Oct. 2006 and U.S. Provisional Patent Application Ser. No. 60/969,173, filed 31 Aug. 2007. Each of the above-listed priority applications are hereby incorporated by reference in their entirety.
FIELD OF INVENTION
• The present invention is generally related to bone cement mixing and delivery systems in which separate components of bone cement are mixed together in a mixer to form a bone cement mixture. The mixture is transferred to a delivery device and then delivered to a target site, such as a vertebral body or other anatomical site.
BACKGROUND OF THE INVENTION
• Bone cement mixing and delivery systems are well known for mixing separate components of bone cement together to form a uniform bone cement mixture and then delivering that mixture to a target site. Typically, such systems employ a mixer having a handle for manually mixing the components. Once mixed, the mixture is then manually transferred to a delivery device such as a syringe. The syringe is used to inject the mixture into the target site. Examples of target sites include medullary canals for total hip arthroplasty procedures, vertebral bodies for vertebroplasty or kyphoplasty procedures, and other sites in which bone cement is required.
• Often, the types of bone cements used in these procedures have short working time windows of only a few minutes thereby affecting the amount of time available for mixing and delivering the mixture to the target site. Current systems require a great deal of user interaction in set-up, including manually mixing the bone cement components and manually transferring the mixture to the delivery device. This user interaction delays delivery of the mixture to the target site, while also exhausting the user's energy. As a result, there is a need for bone cement mixing and delivery systems that are capable of quick set-up, with little user interaction.
• One example of a bone cement mixing and delivery system that attempts to improve set-up time is shown in U.S. Pat. No. 5,571,282 to Earle. Earle discloses a motorized mixer that is used to mix the bone cement components. The mixer mixes the components a pre-selected amount of time, as set by the user. At the end of the pre-selected time, the mixer stops automatically and pressure is applied to the mixture to push the mixture out through a port in the bottom of the mixer to a syringe or a delivery cartridge.
• The release of odors and gases associated with the bone cement components during mixing can also be undesirable. As a result, there is also a need for bone cement mixing and delivery systems that are substantially self-contained such that the odors and gases associated with the components are not substantially released during mixing or transfer.
• One example of a bone cement mixing and delivery system that provides some containment is shown in U.S. Pat. No. 5,193,907 to Faccioli et al. Faccioli et al. discloses an apparatus for mixing and delivering bone cement formed from liquid and powder components. The apparatus comprises a cylindrical body and a plunger slidable within the body. A powder chamber stores the powder component between the plunger and a distal end of the body. A glass ampoule stores the liquid component inside the plunger. To mix the components, a user presses a plug in the plunger's proximal end to urge a tip of the glass ampoule against a cammed surface (or against a piercing member) to release the liquid component. The liquid component then passes through channels defined in the plunger's head to the powder chamber. The liquid and powder are mixed by shaking the body to form the bone cement mixture. After mixing, the plunger is pressed to discharge the bone cement mixture out of an exit port in the body and through a flexible conduit to a target site.
• These prior art systems are suitable for reducing set-up times, conserving a user's energy, and reducing exposure of the user to the bone cement components. However, there is still a need in the art for bone cement mixing and delivery systems that are capable of further reducing set-up time and enabling quick operation to deliver bone cement to a target site.
SUMMARY OF THE INVENTION
• The present invention provides a bone cement mixing and delivery system. The system comprises a mixer for mixing components to form a bone cement mixture and a delivery device for receiving the bone cement mixture from the mixer and for delivering the mixture to a target site. The mixer includes a housing defining a mixing chamber for receiving the components of bone cement. The delivery device includes a reservoir defining a delivery chamber in communication with the mixing chamber for receiving the mixture from the mixing chamber. The mixer further includes a mixing paddle disposed in the mixing chamber for mixing the components to form the mixture. A mixing shaft engages the mixing paddle. A transfer mechanism transfers the mixture out from the mixing chamber and into the delivery chamber. A motor operatively engages both the mixing shaft and the transfer mechanism. The motor operates to rotate the mixing shaft and mix the components in the mixing chamber for a predetermined mixing time to form the mixture. The motor also operates to actuate the transfer mechanism to automatically transfer the mixture from the mixing chamber to the delivery chamber after the predetermined mixing time has elapsed.
• A method of mixing and transferring the components is also provided. The method includes disposing the components in the mixing chamber of the mixer with the mixing paddle. The motor is started to actuate the mixing shaft and move the mixing paddle in the mixing chamber to mix the components for a predetermined mixing time. After the predetermined mixing time elapses, operation of the motor continues to actuate the transfer mechanism. A predetermined amount of the mixture is automatically transferred from the mixing chamber to the delivery chamber after the predetermined mixing time has elapsed and in response to actuating the transfer mechanism.
• The system and method of the present invention have the advantage of using the same motor to actuate both the mixing paddle and the transfer mechanism to minimize weight, cost, and waste, especially considering that the system is preferably intended for single use. Furthermore, the system and method of the present invention reduce user interaction compared to prior art devices and increases the readiness in which an operator can prepare a batch of bone cement for surgical purposes. This is useful when the bone cement increases in viscosity quickly and has a short working window.
BRIEF DESCRIPTION OF THE DRAWINGS
• These and other objects, features and advantages of this invention will be apparent from the following detailed description of the preferred embodiment and accompanying drawings in which:
• FIG. 1 is a top perspective view of a bone cement mixing and delivery system including a mixer and a delivery device;
• FIG. 2 is a side elevational view of the system ofFIG. 1;
• FIG. 3 is a top view of the system ofFIG. 1;
• FIG. 4 is a partial front perspective view of the system with a casing and middle housing portion removed to show a motor and transfer mechanism of the mixer;
• FIG. 5 is a partial top perspective view of a bottom housing portion of the mixer showing a switch and gears of the transfer mechanism;
• FIG. 6 is a cross-sectional view of the system ofFIG. 1 in a mixing phase;
• FIG. 7 is another cross-sectional view of the system ofFIG. 1 in the mixing phase;
• FIG. 8 is a perspective view of a mixing shaft of the mixer;
• FIG. 9A is a top perspective view of a mixing paddle of the mixer;
• FIG. 9B is a top perspective view of the mixing paddle in a flattened state;
• FIG. 10 is a cross-sectional view of the mixing paddle taken generally along the line10-10 inFIG. 9;
• FIG. 11 is a top perspective view of a piston of the mixer;
• FIG. 12 is a bottom perspective view of the piston;
• FIG. 13 is a cross-sectional view of the piston taken generally along the line13-13 inFIG. 11;
• FIG. 14 is a top perspective view of a mixer housing of the mixer;
• FIG. 15 is a bottom perspective view of the mixer housing;
• FIG. 16 is a side elevational view of the mixer housing;
• FIG. 17 is a top perspective view of a transfer disc of the mixer;
• FIG. 18 is a bottom perspective view of the transfer disc;
• FIG. 19 is a cross-sectional view of the transfer disc taken generally along the line19-19 inFIG. 17;
• FIG. 20 is a cross-sectional view of the system ofFIG. 1 in a transfer phase;
• FIG. 21 is another cross-sectional view of the system ofFIG. 1 in the transfer phase;
• FIG. 22 is an exploded view of a base of the mixer;
• FIG. 23 is a top perspective view of the base of the mixer;
• FIG. 24 is a perspective view of a transfer gear;
• FIG. 25 is a perspective view of a driver;
• FIG. 26 is a perspective view of a switch nut;
• FIGS. 27-29 are perspective views of various spur gears;
• FIG. 30 is a top perspective view of a cap of the mixer;
• FIG. 31 is a bottom perspective view of the cap;
• FIG. 32 is a cross-sectional view of the cap taken generally along the line32-32 inFIG. 30;
• FIG. 33 is a top perspective view of a valve ring of the mixer;
• FIG. 34 is a cross-sectional view of the valve ring taken generally along the line34-34 inFIG. 32;
• FIGS. 35A-38B are top perspective views of alternative mixing paddles in normal and flattened states;
• FIG. 39 is a top perspective view of the delivery device;
• FIG. 40 is an exploded perspective view of the delivery device;
• FIG. 41 is a cross-sectional view of the delivery device;
• FIG. 42 is a top view of a valve housing of the delivery device;
• FIG. 43 is a partial cross-sectional perspective view illustrating an optional clutch mechanism of the delivery device;
• FIG. 44 is a top perspective view of an alternative plunger of the delivery device;
• FIG. 45 is a bottom perspective view of an alternative proximal knob portion of the delivery device;
• FIG. 46 is a top perspective view of the delivery device coupled to an extension tube and an enlarged luer-lock connector;
• FIG. 47 is a cross-sectional view of the extension tube and the enlarged luer-lock connector;
• FIG. 48 is a perspective view of a lock fitting of the extension tube;
• FIG. 49 is an electrical schematic of the mixer;
• FIG. 50 is a top perspective view of a motorized delivery device;
• FIG. 51 is an exploded view of the motorized delivery device; and
• FIG. 52 is a cross-sectional view of the motorized delivery device.
DETAILED DESCRIPTION OF THE INVENTION
• For the purpose of promoting an understanding of the present invention, references are made in the text hereof to exemplary embodiments of a bone cement mixing and delivery system, only some of which are depicted in the figures. It should nevertheless be understood that no limitations on the scope of the invention are thereby intended. One of ordinary skill in the art will readily appreciate that modifications such as those involving the materials from which the components are made, the size of the components, functional equivalents of the elements, and the inclusion of additional elements do not depart from the spirit and scope of the present invention. Some of these possible modifications are discussed in the following description. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as support for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or manner.
• As used herein, “distal” refers to the end of the delivery device from which the bone cement mixture is discharged, and “proximal” refers to the end of the delivery device away from the end from which the bone cement mixture is discharged. The terms “substantially” and “approximately,” as used herein, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related.
• Referring in more detail to the drawings, a bone cement mixing and delivery system of the present invention is generally shown at100 inFIG. 1. Thesystem100 includes amixer102 to mix separate components of bone cement to form a bone cement mixture and adelivery device104 to deliver the mixture to a target site. The target site may be an anatomical site such as a vertebral body or the target site may be in or near an implant.
• Thesystem100 is useful in any procedure in which bone cement or any other mixture is required, particularly when time is a constraint and exposure of the material or its vapors to the user is to be minimized. Thesystem100 is capable of mixing the components and automatically transferring the mixture to thedelivery device104 upon completion of mixing with no operator interaction. This reduces variability in mixing between users and creates consistency across multiple users. This automatic transfer feature reduces time and energy otherwise spent by a user to manually mix and transfer the mixture to a delivery device such as a conventional syringe. Thesystem100 also reduces exposure of the user to the bone cement components during mixing and transfer when compared to conventional mixing and delivery devices.
I. Mixer
• Referring toFIGS. 1-3, themixer102 includes abase106 for supporting themixer102 on a surface. Thebase106 includesrubber feet105 for gripping the surface. Acasing107 mounts to the base106 to cover the base and provide an aesthetically pleasing shape to themixer102. Amixer housing108 is coupled to thecasing107. Atransfer conduit110 links themixer housing108 to thedelivery device104. Thetransfer conduit110 conveys the mixture from themixer102 to thedelivery device104. Aswitch cover112 is pivotally mounted to thecasing107 to protect a switch button114 (seeFIG. 4) used to begin operation of themixer102. Once theswitch button114 is pressed, the bone cement components are mixed together to form the mixture and then, once mixing is complete, the mixture is automatically transferred through thetransfer conduit110 to thedelivery device104.
• Referring toFIGS. 4 and 5, themixer102 is shown with thecasing107 removed to expose some of its internal components. As shown, themixer102 is battery-powered.Batteries115 are used to power amotor150 that drives the mixing and transfer operations of themixer102. In one embodiment, abattery pack109 of eightbatteries115 is used to power themotor150. Themotor150 is preferably a reversible DC motor such as those available from Mabuchi Motor Co. of Matsudo City, Japan. Possible models that could be used include Model Nos. RC-280RA-2865 and RC-280SA-2865. Themixer102 is preferably disposable such that themotor150 andbatteries115 are selected for single use. Aswitch117 closes a circuit (seeFIG. 49) between thebatteries115 and themotor150 to begin operation of themotor150. Theswitch button114, when pressed, trips theswitch117 to close the circuit. Once the mixing and transfer operations are complete, themotor150 ceases to operate.
• Referring toFIGS. 6 and 7, thebase106 of themixer102 comprises abottom housing portion118 and amiddle housing portion116 secured to thebottom housing portion118 using conventional fasteners, adhesives, and the like. A mixingshaft120 is rotatably supported between thehousing portions116,118. The mixingshaft120 has amixing gear122 with mixinggear teeth123 at one end. The mixingshaft120 is rotatably supported in thebottom housing portion118 by a centeringpin119. The mixingshaft120 extends from the mixing gear end to a second end124 that is connected to a mixingpaddle126. This connection is preferably releasable, but could include integral or fixed connections.
• Referring toFIGS. 6-10, the mixingpaddle126 includes ahub128 withinner splines130 that interact withouter splines132 on the mixingshaft120 to rotationally lock the mixingshaft120 to the mixingpaddle126 during the mixing phase (shown inFIGS. 8 and 10). Theouter splines132 extend along the entire length of the mixingshaft120 from themixing gear122. This rotational locking feature allows the mixingshaft120 to impart rotational motion to the mixingpaddle126 to adequately mix the bone cement components. When mixing is complete, the rotational lock between the mixingshaft120 and thehub128 is removed to prevent further rotation of the mixingpaddle126 in the transfer phase.
• The preferred embodiment of the mixingpaddle126 is shown inFIGS. 9A,9B, and10. In one embodiment, the mixingpaddle126 is formed of injection molded plastic. In other embodiments, the mixingpaddle126 is formed from a flat piece of plastic or metal material. In these embodiments, the mixingpaddle126 is cut from the flat piece of material and folded/shaped to the configuration shown inFIG. 9A. The mixingpaddle126 includes aflat base section222 and abent flap220 forming an obtuse angle with theflat base section222. Theflat base section222 is fixed to thehub128 by being integrally molded with thehub128 or by adhesive or the like. Thehub128 extends downwardly from theflat base section222. Thebent flap220 is radially spaced from a center of thehub128. As the mixingpaddle126 rotates, thebent flap220 urges the bone cement components upwardly. A pair offlat arms224 extends upwardly from theflat base section222 generally perpendicularly to theflat base section222. Theflat arms224 act as mixing vanes to mix the bone cement components.
• Aflat connector section226 extends between and connects theflat arms224. Theflat connector section226 forms an obtuse angle A with theflat arms224. As a result, when the mixingpaddle126 is urged upwardly in the mixingchamber138 during the transfer phase (further described below), theflat connector section226 strikes a top of themixer housing108. As the mixingpaddle126 continues to move upwardly in the mixingchamber138, the mixingpaddle126 begins to compress toward a flattened configuration. This includes bending theflat arms224 downward toward theflat base section222 about a hinge, then eventually flattening theflat connection section226 and thebent flap220 such that they all fall in generally the same plane as the flat base section222 (seeFIG. 9B).
• Referring toFIGS. 6-7 and11-13, apiston134 supports the mixingpaddle126. More specifically, thehub128 of the mixingpaddle126 is seated in abore136 defined through thepiston134. An o-ring seals thehub128 in thebore136. Thepiston134 is releasably secured in themixer housing108. Another o-ring seals thepiston134 to an interior surface of themixer housing108. Thepiston134 includes a pair offlexible tabs135 that rest beneath ashoulder137 defined in the interior surface of themixer housing108. Theflexible tabs135 hold thepiston134 in place until such time as thepiston134 is forced upwardly to transfer the mixture to thedelivery device104 in the transfer phase. At that point, theflexible tabs135 are forced inwardly to allow thepiston134 to move upwardly along the interior surface of themixer housing108. In the mixing phase, however, thepiston134 remains in place and forms a mixingchamber138 with themixer housing108.
• In one embodiment, themixer102 may be shipped with a powder component of the bone cement stored in the mixingchamber138. In this embodiment, acap140 is releasably coupled to themixer housing108 during shipment to keep the powder component in the mixingchamber138. More specifically, thecap140 is secured to a cylindrically-shapedtop port141 of themixer housing108.
• Thetop port141 defines a pour opening143 (seeFIG. 14) that enters the mixingchamber138 through a plurality ofweb sections145 that form a web. A plurality ofport flanges147 extends radially outwardly from thetop port141 to engage thecap140. Thecap140 includes a plurality of locking tabs149 that engage theport flanges147 to lock thecap140 to themixer housing108. An o-ring seals thecap140 to themixer housing108. When thesystem100 is ready to be used, the user removes thecap140 to add a liquid component of the bone cement through the pour opening143 to the powder component already placed in the mixingchamber138 or also added through the pouropening143. Once the components are disposed in the mixingchamber138, themixer102 is ready for operation.
• Themotor150 operates through a gear arrangement to rotate the mixingshaft120 during the mixing phase to mix the powder and liquid components. Rotation of the mixingshaft120 imparts rotation to the mixingpaddle126, which is disposed in the mixingchamber138. The gear arrangement includes aface gear152 having a set offace gear teeth154. A pinion gear156 (seeFIG. 22) is fixed to a shaft of themotor150 to rotate with themotor150 during operation. Thepinion gear156 haspinion gear teeth157 engaging theface gear teeth154 such that themotor150 drives theface gear152 during operation.
• Theface gear152 drives afirst spur gear160, which drives asecond spur gear166. More specifically, theface gear152 has a lower set ofgear teeth154 continuously engaging an upper set ofspur gear teeth162 formed on thefirst spur gear160. A lower set ofspur gear teeth164 formed on thefirst spur gear160 continuously engages an upper set ofspur gear teeth168 formed on thesecond spur gear166. The upper set ofspur gear teeth168 engages themixing gear teeth123 to rotate the mixingshaft120 and mixingpaddle126 during the mixing phase.
• Thesecond spur gear166 drives athird spur gear167. In particular, a lower set ofspur gear teeth170 formed on thesecond spur gear166 engages a lower set ofspur gear teeth169 formed on thethird spur gear167. Thethird spur gear167 also includes an upper set of spur gear teeth171 (seeFIG. 7). The upper set ofspur gear teeth171 formed on thethird spur gear167 engages a set oftransfer gear teeth176 formed on atransfer gear172. As a result, when themotor150 operates, both the mixingshaft120 and thetransfer gear172 rotate. Each of theface gear152 and spurgears160,166,167 are supported by centering pins captured between themiddle housing portion116 and thebottom housing portion118.
• Thetransfer gear172 is generally cylindrical and includes a first open end and a second, partially closed, end defining an aperture. The mixingshaft120 is rotatably supported in the aperture such that rotation of the mixingshaft120 does not interfere with rotation of thetransfer gear172. The speed with which the mixingshaft120 andtransfer gear172 rotate depends on the gear ratios of the gears. In some embodiments, the gear ratios are set such that thetransfer gear172 rotates slower than the mixingshaft120.
• Thetransfer gear172 forms part of a transfer mechanism of themixer102. The transfer mechanism transfers the mixture out from the mixingchamber138 and into a delivery chamber of thedelivery device104 after mixing.Transfer threads178 are defined on an outer surface of thetransfer gear172. Aswitch nut180 is threaded on the outer surface of thetransfer gear172. Theswitch nut180 is fixed from rotation so that as thetransfer gear172 rotates, theswitch nut180 moves along the outer surface of thetransfer gear172. Theswitch nut180 has twoprojections182 with anotch184 defined therebetween. Thenotch184 rides along an edge of a printedcircuit board186 fixed to thebottom housing118 to prevent rotation of theswitch nut180 with thetransfer gear172. In other words, the edge of the printedcircuit board186 rides in thenotch184 between theprojections182 as thetransfer gear172 rotates thereby preventing theswitch nut180 from rotating. Themotor150, by way of its rotation of thetransfer gear172, operatively engages theswitch nut180. This is best shown inFIG. 5.
• During operation, after theswitch117 has been closed, theswitch nut180 rides along the printedcircuit board186 as it further threads onto thetransfer gear172 in one direction until it engages a second switch190 (seeFIG. 5), spaced from theswitch117. Thus, theswitch nut180 acts as aswitch actuator180. Other suitable actuators could be employed. Thesecond switch190, when tripped by movement of theswitch nut180, opens the circuit between thebatteries115 and themotor150 to shut down operation of the motor150 (seeFIG. 49).
• The transfer mechanism further includes adriver192 that is keyed to thetransfer gear172 to rotate with thetransfer gear172. Thus, thetransfer gear172 operatively couples themotor150 to thedriver192. Thedriver192 includes keyways193 (seeFIG. 22), while thetransfer gear172 includes keys195 (seeFIG. 22) slidably disposed in thekeyways193. In other embodiments, thedriver192 could include thekeys195, while thetransfer gear172 includes thekeyways193. Of course, other coupling mechanisms could be used to lock rotation of thetransfer gear172 to thedriver192. Thedriver192 is free to move axially relative to thetransfer gear172. Thedriver192 has drivingthreads194 defined on its outer surface. During the mixing phase, the drivingthreads194 are rotatably received in abore196 of atransfer disc198. Thetransfer disc198 is coupled to a bottom of themixer housing108 and fixed from movement. Thetransfer disc198 also forms part of the transfer mechanism and acts as adrive nut198 for thedriver192.
• During the mixing phase, the drivingthreads194 rotate within thebore196 of thetransfer disc198 and engage correspondingthreads202 in thebore196. Thus, thetransfer disc198 operates as a fixed drive nut.FIGS. 6 and 7 show the drivingthreads194 fully advanced through thebore196. This represents the end of the mixing phase. Aspring203 biases thedriver192 upwardly in the cavity of thetransfer gear172 to facilitate engagement with thethreads202. The time required for the drivingthreads194 to fully advance through thebore196 represents the mixing phase. In other words, a predetermined mixing period is set by the amount of time it takes for the drivingthreads194 to fully advance through thetransfer disc198. Once the drivingthreads194 completely pass through thebore196, the transfer phase begins. The transfer phase continues for a predetermined transfer period, which is defined between the start of transfer and the actuation of thesecond switch190, which ceases operation of themotor150.
• Referring toFIGS. 20 and 21, when thedriver192 advances in the transfer phase, it pushes thepush cap200 axially upwardly against thepiston134, which in turn urges thepiston134 upwardly to move through the mixingchamber138. Thepiston134 is sealed to the wall of themixer housing108 and includes a face that contacts the mixture in the mixingchamber138. The mixture is pushed upwardly through an exit port204 (also referred to as atransfer port204; seeFIG. 21) into thetransfer conduit110 and then into thedelivery device104. For this reason, thepiston134 is also considered part of the transfer mechanism of themixer102.
• As thedriver192 advances in the transfer phase and moves thepiston134 through the mixingchamber138, thedriver192/piston134 disengages the mixingpaddle126 from the mixingshaft120. More specifically, thehub128 withinner splines130 is lifted off theouter splines132 on the mixingshaft120 to rotationally unlock the mixingshaft120 from the mixingpaddle126 during the transfer phase. The mixingshaft120 is held down by thetransfer gear172 while the mixingpaddle126 is disengaged from the mixingshaft120. As thepiston134 rises in the mixingchamber138, the mixingpaddle126 folds down to a compact size to permit a majority of the mixture to be pressed out of the mixingchamber138 and into thedelivery device104.
• Themotor150 operates through the gear arrangement to rotate the mixingshaft120 and actuate the mixingpaddle126 during the mixing phase to mix the powder and liquid components, while also rotating thetransfer gear172 to actuate the transfer mechanism to automatically transfer the mixture from the mixingchamber138 to the delivery chamber of thedelivery device104 after the predetermined mixing period has elapsed. In other words, themotor150 operatively engages both the mixingshaft120 and the transfer mechanism (including thetransfer gear172,driver192,piston134, etc.). Themotor150 continues operation from its start, upon actuation of theswitch117, until it stops upon actuation of thesecond switch190, during which time themotor150 operates to mix the components in themixer102 and transfer the mixture to thedelivery device104. In one embodiment, theswitch117 and thesecond switch190 are combined into a single switch (not shown) that is closed to start operation of themotor150 by an actuator, and opened to stop operation of themotor150.
• In still other embodiments, thesecond switch190 reverses the polarity of themotor150 and causes thetransfer gear172 to reverse its rotation. Consequently, theswitch nut180 changes direction and rides back along the printedcircuit board186. In this embodiment, thethreads202 are configured such that during the mixing phase the drivingthreads194 cannot engage thethreads202 of thetransfer disc198. However, when thepolarity switch190 is tripped by theswitch nut180, thedriver192 reverses its direction of rotation with thetransfer gear172 and engages thethreads202 in a manner that advances thedriver192 axially during the transfer phase. In this embodiment, a third switch (not shown) or other mechanism would be required to be tripped by theswitch nut180 as it travels back along the printedcircuit board186 to stop operation of themotor150.
• As shown in FIGS.7 and14-19, the bottom of themixer housing108 includes aflange173 and ashort wall175 extending downwardly from theflange173. A plurality of locking tabs177 (seeFIG. 15) are spaced circumferentially about theshort wall175 and extend radially outwardly from theshort wall175. During assembly of themixer102, the lockingtabs177 are inserted into openings179 (seeFIG. 17) defined in a top of thetransfer disc198. Thecasing107 is captured between themixer housing108 and thetransfer disc198 when this is done (seeFIG. 21). Themixer housing108 is then rotated one-quarter turn such that the lockingtabs177 slide beneath corresponding lockingmembers183 on thetransfer disc198 until they reach stops199. Thepiston134 rests on top of thetransfer disc198 and is initially coupled to thetransfer disc198 by thepush cap200.
• FIG. 22 illustrates an exploded view of the base106 including thebottom housing portion118, themiddle housing portion116, and the gear arrangement disposed therebetween for converting motor operation into mixing and transfer operations.FIG. 23 shows the base106 fully assembled.
• FIGS. 24-29 illustrate perspective views of thetransfer gear172, thedriver192, theswitch nut180, thefirst spur gear160, thesecond spur gear166, and thethird spur gear167.
• Referring toFIGS. 30-32, thecap140 is shown. Thecap140 includes a top232. Acap wall234 is disposed on the top232 and extends downwardly from the top232 to abottom wall236. Agripping flange238 extends downwardly from the top232 and is spaced from thecap wall234. A plurality of lockingtabs240 are disposed on thegripping flange238 and extend radially inwardly into a gap between thegripping flange238 and thecap wall234. The lockingtabs240 engage thetabs147 on thetop port141.
• Referring toFIGS. 7,33, and34, avalve206 is arranged in theexit port204 to prevent the escape of unmixed components during mixing. Referring toFIG. 34, the valve includes a plastic ormetal ring210 having a plurality ofapertures212 for receiving anelastomeric material213 in a molding process. Thematerial213 fills in theapertures212 as shown inFIG. 34 and includescross-cut slits214 that remain closed in the mixing phase, but open up and allow the mixture to flow therethrough into thetransfer conduit110 during the transfer phase.
II. Alternative Mixing Paddles
• Alternative embodiments of the mixingpaddle126 are shown inFIGS. 35A-38B. InFIGS. 35A and 35B, the mixingpaddle126′ is formed of plastic and includes a pair offlat arms224′ extending upwardly from aflat base section222′. A pair of opposedbent flaps220′ form an obtuse angle with theflat base section222′. In this embodiment, theflat arms224′ are opposed from one another on opposite sides of a center of the mixingpaddle126′. Theflat arms224′ further include bent ends225′ that strike the top of the mixer housing208 in the transfer phase and bend inwardly to flatten theflat arms224′.
• Referring toFIGS. 36A and 36B, the mixingpaddle126′ is formed of metal such as stainless steel or aluminum.
• InFIGS. 37A and 37B, a mixingpaddle126″ has a pair ofopposed arms224″ that are pivotally connected to aflat base section222″ by a pair of pivot pins229.
• InFIGS. 38A and 38B, a mixingpaddle126′″ includes aflat base section222′″, abent flap220′″ forming an obtuse angle with theflat base section222′″, and a singleflat arm224′″ extending upwardly generally perpendicularly to theflat base section222′″. Anextension231 extends at an obtuse angle for crossing themixing chamber138. In each of the embodiments of the alternative mixing paddles, thearms224′,224″,224′″ are configured to be supported by the wall of themixer housing108 during rotation in the clockwise direction (when viewed from above), but unsupported when rotating in the counterclockwise direction. When unsupported, they are urged into their compressed state. This is useful when themotor150 changes direction during the transfer phase, as described in the alternative transfer embodiment above.
• Themixer housing108,transfer disc198, mixingshaft120,transfer gear172,face gear152, spur gears160,166,167,switch nut180,driver192,piston134,cap140, mixingpaddle126,bottom housing portion118,middle housing portion116, casing107, and switchcover112 are preferably formed of a bio-compatible plastic material such as nylon, PBT (polybutylene terephthalate), PC (polycarbonate), ABS (acrylonitrile butadiene styrene), glass-filled nylon, glass-filled polyetherimide, or the like.
III. Delivery Device
• Referring toFIGS. 39-42, thedelivery device104 is shown. Thedelivery device104 comprises areservoir302 defining the delivery chamber for receiving the bone cement mixture from thetransfer conduit110 during the transfer phase. Thereservoir302 includes an entry port314 (or inlet port314) defined in a sidewall of thereservoir302. A valve housing316 (see alsoFIG. 42) is outfitted with an o-ring318 and is seated in theentry port314. The valve housing includes a plurality offlow paths319 and acentral bore321. As shown inFIG. 41, a one-way umbrella valve320 is supported in thecentral bore321 of thevalve housing316 such that the bone cement mixture opens thevalve320 to fill thereservoir302. The one-way umbrella valve320 prevents the bone cement mixture from re-entering themixer102 during the transfer phase. Ahandle304 is mounted about thereservoir302 for grasping by the user.
• Arotatable fitting322 is secured in thevalve housing316 during the mixing and delivery phases. To accomplish this, therotatable fitting322 fits through anaperture325 in thehandle304. Therotatably fitting322 includes a pair of diametrically opposed lockingtabs306 that engages thehandle304. Thehandle304 includes a plurality of lockingflanges327 spaced circumferentially from one another in theaperture325. The lockingflanges327 extend radially inwardly into theaperture325. During assembly, the lockingtabs306 pass into theaperture325 between the lockingflanges327 and are rotated into place with the lockingtabs306 disposed beneath the lockingflanges327. Anannular flange329 of therotatable fitting322 rests on top of the lockingflanges327 when in position (seeFIG. 41).
• One end of thetransfer conduit110 fits into therotatable fitting322. A throughbore331 is defined through therotatable fitting322 to transfer the bone cement mixture to thereservoir302 from thetransfer conduit110. During transfer the bone cement mixture passes through the throughbore331 under pressure thereby opening the one-way umbrella valve320 and passing through the flow paths319 (seeFIG. 42) into thereservoir302. Once transfer is complete, therotatable fitting322 is rotated counterclockwise to release the rotatable fitting322 from thevalve housing316 thereby allowing the user to remove thedelivery device104 from its cradle mounts333 on themixer102 in preparation for delivering the bone cement mixture to the target site.
• Anut324 is mounted to a proximal end of thereservoir302. In particular, the proximal end of thereservoir302 has arectangular flange326 for supporting thenut324. Therectangular flange326 slides into aslot328 defined in thenut324. Thenut324 has a generally box-like shape that is secured between twohalves330,332 of thehandle304. Eachhalf330,332 of thehandle304 has a complimentary box-shapedcavity334 such that thenut324 fits snugly in thecavities334 when thehalves330,332 are fixed together. Thehalves330,332 may be fixed together by conventional fasteners, adhesives, and the like.
• Aplunger310 drives the mixture through the delivery chamber of thereservoir302 during delivery. Theplunger310 includes a threadedshaft336 that engagesthreads338 of thenut324. Aplunger head344 is snap-fit to the threadedshaft336 to form a distal end of theplunger310. Theplunger head344 is snap-fit to the threadedshaft336 by inserting astem346 of theplunger head344 into abore348 defined through the threadedshaft336. Referring toFIGS. 40 and 41, thestem346 has a pair of diametrically opposed detent ramps354 that slide through thebore348 in a compressed configuration (by being pressed together via aslot349 defined through the stem346) until theramps354 pass ashoulder356 in thebore348. Once they pass theshoulder356, theramps354 spring outwardly to engage theshoulder356 and prevent withdrawal of theplunger head344. An o-ring350 is seated with adynamic seal351 in an outer groove defined in theplunger head344 to seal against an interior of thereservoir302.
• Aproximal end311 of theplunger310 has a generally box-like shape. Aknob312 is mounted about theproximal end311 of theplunger310 to facilitate rotation of theplunger310. Theknob312 has aproximal knob portion340 defining a box-shapedcavity341 for receiving theproximal end311 of theplunger310 such that as the user rotates theproximal knob portion340, theplunger310 also rotates. Adistal knob portion342 is fastened to theproximal knob portion340 using fasteners, adhesives, or the like. Theproximal end311 of theplunger310 is captured between the proximal340 and distal342 knob portions to prevent theproximal end311 of theplunger310 from slipping out of the box-shapedcavity341.
• IV. Alternative Delivery Device with Clutch
• Referring toFIGS. 43-45, analternative plunger shaft360 is shown. Referring specifically toFIG. 44, a proximal end of theplunger shaft360 includes aflange362 and a plurality ofprojections364 disposed on theflange362. The plurality ofprojections364 extend proximally from theflange362. Theprojections364 are circumferentially spaced from one another about a periphery of theflange362. Each of theprojections364 has avertical surface366 and an angled surface368 (forms acute angle with flange362) meeting at aplateau370 generally parallel to theflange362. In the embodiment, aknob371 is mounted to the proximal end of theplunger shaft360 to facilitate rotation of theplunger shaft360. Theknob371 includes aproximal knob portion372. Theproximal knob portion372 includes a top374 and a plurality ofcomplimentary projections376 disposed on the top374 and extending distally from the top374. Thecomplimentary projections376 mate with theprojections364 on theflange362 by fitting in spaces defined between theprojections364 on theflange362.
• Each of thecomplimentary projections376 also includes avertical surface378 and anangled surface380 meeting at aplateau382 generally parallel to the top374. Adistal knob portion384 is fastened to theproximal knob portion372 using fasteners, adhesives, or the like. The proximal end of theplunger shaft360 is captured between the proximal372 and distal384 knob portions. Theplunger shaft360 passes through abore385 defined through thedistal knob portion384. Aspring386 rests on ashoulder388 defined in thedistal knob portion384 about thebore385. Thespring386 acts between theshoulder388 and theflange362.
• Thespring386, along with theprojections364,376, form a clutch mechanism. This clutch mechanism can be configured to slip when undesired pressures are reached in thedelivery device104. During use, when a user is rotating theknob371, theprojections376 formed on theproximal knob portion372 engage theprojections364 formed on theflange362 of theplunger shaft360. In particular, theangled surfaces368,380 engage one another as the user rotates theknob371 clockwise. Thespring386 acts to keep theangled surfaces368,380 in engagement during normal operation. However, when undesired pressures are reached theangled surfaces368,380 begin to slip and theflange362 separates from theproximal knob portion372. As a result, theprojections364,376 slide out of engagement thereby preventing further advancement of theplunger shaft360 until pressure is normalized. Different spring constants can be used to alter the pressure at which the clutch mechanism is actuated. Furthermore, theprojections364,376 could be oriented radially, as opposed to axially, such that axial forces supplied by the user does not affect the clutch mechanism's operation.
• V. Extension Tube with Enlarged Connector
• Referring toFIG. 46, anextension tube400 is shown mounted to the distal end of thereservoir302. In one embodiment, theextension tube400 is automatically primed with bone cement during the transfer phase. In other words, thesystem100 is designed for use with specified mixture volumes that fill both thereservoir302 and theextension tube400 in the transfer phase. This eliminates the need for the user to prime theextension tube400 manually.
• Referring toFIGS. 47 and 48, theextension tube400 includes a tube fitting402 for securing theextension tube400 to thedelivery port306 of thereservoir302. Referring back toFIG. 39, thedelivery port306 includes a pair of diametricallyopposed projections404 and the tube fitting402 includes a pair of diametricallyopposed channels406 for receiving theprojections404 when the tube fitting402 is axially mounted onto thedischarge port306. Once theprojections404 bottom-out in thechannels406, the tube fitting402 is rotated. Theprojections404 then ride in diametricallyopposed slots408 defined through thetube fitting402. The tube fitting402 is then prevented from axially sliding off thedelivery port306. In other embodiments, the tube fitting402 is fixed to thedelivery port306 with adhesive, press fit, welding, or the like.
• Referring toFIG. 47, an enlarged luer-lock connector410 is mounted to a distal end of theextension tube400. The luer-lock connector410 comprises aknob412, aspindle414, and acollar416. Thecollar416 includes aside port418 defining aside bore426. Amain bore420 is defined through thecollar416 normal to theside port418. The distal end of theextension tube400 fits into the side bore426 of theside port418. Theextension tube400 may be fixed in theside port418 by press fit, ultrasonic welding, adhesive, or the like.
• Thespindle414 is rotatably supported in themain bore420 of thecollar416. A pair of o-rings415 seals thespindle414 in themain bore420. Thespindle414 includes a throughbore422 and across bore424 aligned with the side bore426 in theside port418. Thecross bore424 is disposed between the o-rings415. Theknob412 includes astem428 that fits into the throughbore422 in a top of thespindle414. Thestem428 is fixed in the throughbore422 by a press-fit, ultrasonic welding, adhesive, or the like.
• Theknob412 further includes a graspingportion430 shaped for grasping by a hand of the user. Thespindle414 fits inside anannular cavity432 in theknob412. A bottom of thespindle414 has aconnector portion434, e.g., a standard luer-lock fitting434. The throughbore422 continues through the luer-lock fitting434. The luer-lock fitting434 is configured for attaching to a corresponding luer-lock fitting436 on adelivery cannula440. During use, the user grasps the graspingportion430 of theknob412 and rotates theknob412 andspindle414 to lock the luer-lock fitting434 of thespindle414 on the luer-lock fitting436 on thedelivery cannula440. The oversizedgrasping portion430 facilitates easier connection of theextension tube400 to thedelivery cannula440 to deliver the bone cement mixture through theextension tube400, the throughbore422, thedelivery cannula440, and to the target site.
• Thereservoir302,rotatable fitting322, handle304,knob312,plunger310,nut324,valve housing316, tube fitting402, and enlarged luer-lock connector410 are preferably formed of a bio-compatible plastic material such as nylon, PBT (polybutylene terephthalate), PC (polycarbonate), ABS (acrylonitrile butadiene styrene), glass-filled nylon, glass-filled polyetherimide, or the like. Theumbrella valve320 is preferably formed of nitrile.
• VI. Alternative Delivery Device with Delivery Motor
• Referring toFIGS. 50-52, an alternative delivery device504 is shown. Thedelivery device500 comprises areservoir502 defining a delivery chamber for receiving the bone cement mixture from thetransfer conduit110 during the transfer phase. Thereservoir502 threadably engages acap505 seated in anend plate507. Theend plate507 is supported between and fixed to twoside plates509. Theend plate507 has a U-shaped cutout portion into which thecap505 extends. The cutout portion supports thecap505. Abottom plate506 supports and is fixed to theside plates509. Amiddle plate513 is fixed to thebottom plate506 and the twoside plates509. Themiddle plate513 is preferably rectangular in shape to prevent rotation of themiddle plate513 between theside plates509. Anut524 is disposed between themiddle plate513 and thecap505. Thenut524 is fixed from rotation relative to theplates507,509,513 by being fixed to themiddle plate513 by adhesive, welding, fasteners, or the like.
• Referring toFIGS. 51 and 52, aplunger510 drives the mixture through the delivery chamber of thereservoir502 during delivery. Theplunger510 includes a threadedshaft536 that engages threads (not shown) of thenut524. Aplunger head544 is fixed to the threadedshaft536 to form a distal end of theplunger510. An o-ring550 with a dynamic seal551 is seated in an outer groove defined in theplunger head544 to seal against an interior of thereservoir502.
• A proximal end511 of theplunger510 is slidably disposed in arotating drive shaft600. Thedrive shaft600 is hollow and includes a key602 disposed along its internal surface. The key602 protrudes radially inwardly. Theplunger510 includes akeyway604 disposed in an outer surface of the threadedshaft536. The key602 is configured to slide in thekeyway604 as thedrive shaft600 rotates due the fixed nature of thenut524.
• Referring toFIG. 52, adelivery motor606 andgear box608 operate to rotate thedrive shaft600. Thegear box608 includes abox610 and acover612. Thedelivery motor606 is supported in a mountingsleeve614 disposed on thecover612. Amotor shaft616 penetrates through thecover612 into thegear box608. Apinion gear616 is fixed to themotor shaft616 to rotate with thedelivery motor606 during its operation. A series of spur gears618,620,622,624 are rotatably supported byshafts626,628. Theshafts626,628 are fixed to thebox610 and cover612 for support.
• A proximal end of thedrive shaft600 is rotatably supported in thebox610 by abushing630. Adrive gear632 is fixed to the proximal end of thedrive shaft600 and rotatably supported by ashaft634. Theshaft634 is fixed to thecover612. The series of spur gears618,620,622,624 transfer power from themotor shaft616 to thedrive gear632 during operation. Aswitch640 controls operation of thedelivery motor606. Thedelivery motor606 may be powered by abattery pack607. After the mixture has been transferred from the mixingchamber138 to the delivery chamber of thereservoir502, as described above, the user can operate thedelivery motor606 to delivery the mixture to the target site.
VII. Drool Valve and Viscosity Meter
• Referring back toFIG. 50, adrool valve700 may be positioned at any point along theextension tube400, including at the distal end of theextension tube400. Thedrool valve700 may be a motor-controlled valve or a solenoid valve. Thedrool valve700 is controlled by acontroller702. Thecontroller702, in this embodiment, also controls thedelivery motor606 through theswitch640. Thedrool valve700 operates to discontinue flow of the mixture through theextension tube400 from thedelivery device500 upon actuation of thedelivery switch640 thereby preventing excess mixture from entering the target site. Without thedrool valve700, when the user actuates thedelivery switch640 to stop operation of thedelivery motor606, there is still pressure in theextension tube400 due to the compressible nature of the mixture. This pressure tends to deliver an additional amount of the mixture to the target site after the user desires to stop flow of the mixture. With thedrool valve700, the amount of the mixture delivered can be better controlled.
• In operation, the user actuates theswitch640 to send power to thedrool valve700 and thedelivery motor606. This opens thedrool valve700 and starts operation of thedelivery motor606. Operation of thedelivery motor606 rotates thedrive shaft600 and advances theplunger510 in thereservoir502 to begin delivering the mixture from thereservoir502, down theextension tube400, to the target site. When the user wishes to stop the flow of the mixture, theswitch640 is again actuated to signal thecontroller702 that thedelivery motor606 is to be stopped and thedrool valve700 is to be closed. Thecontroller702 then discontinues power to thedelivery motor606 and thedrool valve700.
• Aviscosity meter710 monitors current draw on thedelivery motor606 to approximate the viscosity of the mixture in thereservoir502. Theviscosity meter710 can be a current meter integrated into thecontroller702 to monitor the current draw from thedelivery motor606. Thecontroller702 then correlates current draw to viscosity by way of a look-up table using correlation values that can be easily derived. Adisplay712 then displays the approximate viscosity of the mixture. Of course, the viscosity measurement is an estimate and not an exact measurement of viscosity, but can be useful in determining how much longer the working time window for the particular bone cement being used will remain open.
• While this description is directed to a few particular embodiments, it is understood that those skilled in the art may conceive of modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations that fall within the purview of this description are intended to be included herein as well. It is understood that the description herein is intended to be illustrative only and is not intended to be limited.

Claims (7)

1. A bone cement mixing and delivery system, said system comprising:

a mixer including:

a shell, said shell defining a mixing chamber for receiving bone cement-forming components, the shell having a discharge port that opens out of the mixing chamber; and

a piston disposed in said shell and having a face directed towards the shell mixing chamber, said piston being moveable mounted to said shell to move through the mixing chamber so as to push the cement out through the shell discharge port;

a delivery device, said delivery device having:

a tube that defines a reservoir, said tube having a distal end opening, a proximal end opening and an entry port into the reservoir, the entry port being separate from the distal and proximal end openings, said entry port being in fluid communication with said mixer shell discharge port; and

a plunger mounted to tube that extends from the proximal opening of said tube, said plunger configured to slide toward the distal opening to push cement out of the distal opening;

a flexible extension tube that extends forward from the delivery tube distal opening, said extension tube having a longitudinal axis and a lumen that extends along the longitudinal axis, the lumen opening at the distal end of said tube; and

a connector, said connector mounted to the distal end of said extension tube, said connector including:

a housing, said housing being attached to the distal end of said extension tube and having a main bore into which the extension tube distal end lumen opens, the main bore being angularly offset from the longitudinal axis of said extension tube;

a spindle rotatably seated within the main bore of said housing, said spindle having a fitting configured for removably receiving a delivery cannula that is configured for insertion into living tissue, a bore in selective fluid communication with the lumen of said extension tube wherein the spindle bore extends to the cannula, said spindle further being shaped to rotate between a closed position in which said spindle blocks flow from the extension tube into the spindle bore, and an open position in which spindle allows flow from the extension tube into the spindle bore so that the cement can flow into the cannula; and

a knob attached to said spindle for rotating said spindle between the closed and open positions, said knob having a grasping portion, wherein said knob grasping portion extends radially outwardly beyond said housing.

2. The bone cement mixing and delivery system ofclaim 1, wherein said spindle includes opposed first and second ends where said knob is located at the first end, and said fitting located at the second end.

3. The bone cement mixing and delivery system ofclaim 1, wherein said delivery system further includes a tube fitting, said tube fitting connecting a proximal end of said extension tube with the distal end opening of said delivery device tube so that extension tube is in fluid communication with said delivery tube.

4. The bone cement mixing and delivery system ofclaim 1, wherein said spindle is sealed within the main bore of said housing a pair of O-rings.

5. The bone cement mixing and delivery system ofclaim 1, wherein said housing is further formed to include a side port that extends outwardly from said housing, said side port having a side bore wherein said side bore is in registration with the lumen opening at the distal end of said extension tube.

6. The bone cement mixing and delivery system ofclaim 1, wherein said spindle fitting is orthogonal to the longitudinal axis of said extension tube.

7. The bone cement mixing and delivery system ofclaim 1, wherein said mixer includes an electrically actuated drive assembly disposed in a base that is connected to: a paddle to move said paddle in the mixing chamber, and said piston to move said piston through the mixing chamber.

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