Patent Abstract:
The present invention describes apparatus and methods for tying a filament across subcutaneous punctures. According to some embodiments, the apparatus and methods provide pre-tied knots that are inserted into a bodily lumen. Needles flanking the subcutaneous puncture are inserted into the lumen and grab the pre-tied knots. The pre-tied knots are pulled through tiny holes flanking the subcutaneous puncture by the needles, leaving an internal length of the filament across the subcutaneous puncture. The filament is then externally tied, closing the subcutaneous puncture.

Full Description:
RELATED APPLICATION 
     This is a division of U.S. patent application Ser. No. 11/130,916 filed on 17 May 2005, the disclosure of which is incorporated in its entirety by this reference, now issued as U.S. Pat. No. 8,038,687 on 18 Oct. 2011. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to medical devices and more particularly to suturing devices for closing a hole in a corporeal vessel wall. 
     BACKGROUND 
     Various surgical procedures are routinely carried out intravascularly or intraluminally. For example, in the treatment of vascular disease, such as arteriosclerosis, it is a common practice to invade the artery and insert an instrument (e.g., a balloon or other type of catheter) to carry out a procedure within the artery. Such procedures usually involve the percutaneous puncture of the artery so that an insertion sheath can be placed in the artery. The insertion sheath enables the introduction of other instruments (e.g., a catheter) to an operative position within the vascular system. Intravascular and intraluminal procedures unavoidably present the problem of stopping the bleeding at the percutaneous puncture after the procedure has been completed and after the instrument (and any insertion sheaths used therewith) has been removed. Bleeding from puncture sites, particularly in the case of femoral arterial punctures, is typically stopped by utilizing vascular closure devices, such as those described in U.S. Pat. Nos. 6,179,863; 6,090,130; and 6,045,569, which are hereby incorporated by this reference. 
     The above patents describe a tissue puncture closure device in which, generically, a suture filament is pre-threaded through an elongated sheath (used to access the tissue puncture), through an anchor exterior to the distal tip of the sheath, and then back into the sheath where it is attached to a sealing plug disposed on the suture filament line within the sheath. The sheath is inserted through an incision in the skin and through the puncture in the tissue wall until the anchor is deployed within the luminal cavity of the organ or artery, with the sealing plug remaining outside the luminal cavity. Successful deployment of the sealing plug requires that the sealing plug be manually ejected from within the sheath and tamped down to the outer surface of the tissue puncture using a tamping tube, while simultaneously pulling on the filament to cinch tight the filament connecting the anchor and sealing plug. The anchor and the sealing plug are brought together in a pulley-like fashion with a self-tightening slip-knot in the filament, such that the tissue puncture is sandwiched between the anchor and sealing plug, thereby sealing the tissue puncture and stopping bleeding. 
     Using the prior devices, however, there is a risk of inserting the sealing plug into the artery. Complications may arise if the sealing plug enters the artery. In addition, the sealing plug may not be deployed close enough to the hole to effectively seal the puncture, which may result in prolonged bleeding and slower recovery. Some doctors would prefer to close the puncture instead by tying a suture across the hole. However, normally the puncture is relatively small, and often inaccessible through the incision leading to the puncture. 
     SUMMARY 
     In one of many possible embodiments, the present invention provides a tissue puncture closure device. The tissue puncture closure device comprises a central shaft having first and second end portions and a slotted portion disposed between the first and second end portions, a filament extending from the first portion to the second portion, and first and second open loop knots disposed at least partially within the slotted portion. The slotted portion may comprise first and second elongated slots receptive of a needle. The slotted portion may also comprise third and fourth slots, wherein the third and fourth slots comprise a smaller width than the first and second slots. First portions of the first and second open loop knots may extend at least partially through the third slot, and second portions of the first and second open loop knots extend at least partially through the fourth slot. The first, second, third, and fourth slots may be arranged approximately 90 degrees from one another such that the first and second slots are substantially opposite of one another, and the third and fourth slots are substantially opposite of one another. 
     According to some aspects, the central shaft extends through a vascular access sheath. In addition, a first curved needle may extend through a first side port in the vascular access sheath, into the slotted portion, and at least partially through the first open loop knot. Similarly, a second curved needle may extend through a second side port in the vascular access sheath, into the slotted portion, and at least partially through the second open loop knot. 
     According to some embodiments, a first cannula needle extends through a first side port in the vascular access sheath and diverges from the vascular access sheath. A first needle passes through the first cannula needle, curves into the slotted portion, and extends at least partially through the first open loop knot. A second cannula needle extends through a second side port in the vascular access sheath and diverges from the vascular access sheath. A second needle extends through the second cannula needle, curves into the slotted portion, and extends at least partially through the second open loop knot. According to some aspects, the first and second open loop knots are remotely tightenable. 
     Other aspects of the invention provide a vascular closure system. The vascular closure system comprises a closure device including a central shaft having an open channel portion disposed between first and second end portions, and a filament looping through the central shaft such that the filament is tied into first and second open knots at the open channel portion. The system may include a vascular access sheath receptive of the closure device. The central shaft may include first and second end portions flanking the open channel portion such that the filament extends from the first end portion, to the second end portion, and back to the first end portion. One or more free ends of the filament are accessible to an operator. The system may also include first and second cannula needles extending through first and second side ports, respectively, in the vascular access sheath, a first curved needle extending through the first cannula needle, into the open channel portion, and partially through the first open loop knot, a second curved needle extending through the second cannula needle, into the open channel portion, and partially through the second open loop knot, such that each of the first and second curved needles comprises a step at an end thereof. Each of the first and second curved needles may comprises a nitinol needle having sufficient elasticity to pass through the first and second straight cannula needles and return to a curved shape after passing through ends thereof. The first and second open knots may be remotely tightenable against the steps of the first and second curved needles, respectively, by applying tension to the filament. 
     Another aspect of the invention provides a vascular closure system comprising a vascular access sheath having a plurality of side-ports disposed at a distal end portion, an open-loop knot carrying device insertable into the vascular access sheath, a plurality of cannula needles, each of the plurality of cannula needles insertable through a corresponding one of the plurality of side-ports, and a plurality of curved needles. Each of the plurality of curved needles is insertable through a corresponding one of the plurality of cannula needles. 
     Another aspect of the invention provides a method of closing a subcutaneous puncture. The method comprises inserting a filament into a lumen through the puncture, inserting first and second needles into the lumen through holes flanking the puncture, grabbing the filament with each of the first and second needles, retracting the filament through the holes flanking the puncture, and tying the filament across the puncture. The method may also include inserting first and second cannula needles into the lumen to create the flanking holes. 
     According to some aspects of the invention, the grabbing comprises passing the first needle partially through a first open-loop knot disposed in the filament inside the lumen, passing the second needle partially through a second open-loop knot disposed in the filament inside the lumen, and remotely cinching the first and second open-loop knots around the first and second needles, respectively. The inserting of the filament may comprise passing a shaft through a vascular access sheath, such that the filament traverses the shaft and is pre-tied into first and second open-loop knots at a slotted portion of the shaft. 
     Another aspect of the invention provides a method of closing a subcutaneous puncture. The method includes inserting a tubular shaft comprising a filament having first and second open-loop knots into a lumen through the puncture, advancing first and second cannula needles flanking and spaced from the tubular shaft into the lumen, passing first and second curved needles through the first and second cannula needles, respectively, cinching the first and second open-loop knots to the first and second curved needles, respectively, retracting the first and second curved needles through the first and second cannula needles, respectively, and tying the filament across the puncture. 
     Another aspect of the invention provides a method of making a subcutaneous puncture closure device, comprising providing a tubular shaft having a slotted portion, tying first and second knots in a filament, inserting the filament into a tubular shaft, placing first portions of the first and second knots in a first slot of the slotted portion, and placing second portions of the first and second knots in a second slot of the slotted portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate various embodiments of the present invention and are a part of the specification. The illustrated embodiments are merely examples of the present invention and do not limit the scope of the invention. 
         FIG. 1  is a side view, partly in section, of an internal tissue puncture closure device according to the prior art. 
         FIG. 2  is a side view of the tissue puncture closure device of  FIG. 1  inserted through an insertion sheath and engaged with an artery, the artery shown in section, according to the prior art. 
         FIG. 3  is a side view of the tissue puncture closure device, insertion sheath, and artery of  FIG. 2 , wherein the tissue closure device and insertion sheath are being withdrawn from the artery to deploy a collagen sponge according to the prior art. 
         FIG. 4  is a side view of the tissue puncture closure device, insertion sheath, and artery shown in  FIG. 3  with a tamping tube fully exposed and being used to tamp the collagen sponge according to the prior art. 
         FIG. 5A  is a side perspective view, partly in section, of a tissue puncture closure device with a suture loop closure mechanism inserted into an artery according to one embodiment of the present invention. 
         FIG. 5B  is the side perspective view shown in  FIG. 5A , with a slotted portion removed to more clearly illustrate the suture knots according to one embodiment of the present invention. 
         FIG. 6  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 5A  with flanking cannula needles according to one embodiment of the present invention. 
         FIG. 7  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 6  with curved needles extending through the flanking cannula needles according to one embodiment of the present invention. 
         FIG. 8  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 7  with curved needles extending through the flanking cannula needles and the suture knots tightened around ends of the curved needles according to one embodiment of the present invention. 
         FIG. 9  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 8  with the curved needles being retracted toward the cannula needles according to one embodiment of the present invention. 
         FIG. 10  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 9  with the cannula needles being retracted according to one embodiment of the present invention. 
         FIG. 11  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 10  with the suture loop closure mechanism being retracted from the artery according to one embodiment of the present invention. 
         FIG. 12  is a side perspective view, partly in section, of the suture loop closure mechanism shown in  FIG. 11  with the suture loop closure mechanism being nearly fully retracted from the artery, leaving the suture extended across the puncture according to one embodiment of the present invention. 
         FIG. 13  a side perspective view, partly in section, of the artery with the suture loop closure mechanism of  FIG. 12  fully removed from the artery and the suture tied across the puncture according to one embodiment of the present invention. 
     
    
    
     Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. 
     DETAILED DESCRIPTION 
     As mentioned above, vascular procedures are conducted throughout the world and require access to an artery through a puncture. Most often, the artery is a femoral artery. To close the puncture following completion of the procedure, many times a closure device is used to sandwich the puncture between an anchor and a sealing plug. However, sometimes the sealing plug is not properly seated against an exterior situs of the arteriotomy. If the plug does not seat against the arteriotomy, there is a potential for elongated bleeding. The present invention describes methods and apparatus to tie a suture across an arteriotomy. While the vascular instruments shown and described below include certain insertion sheaths and puncture sealing devices, the application of principles described herein to are not limited to the specific devices shown. The principles described herein may be used with any vascular closure device. Therefore, while the description below is directed primarily to arterial procedures and certain embodiments of a vascular closure device, the methods and apparatus are only limited by the appended claims. 
     Referring now to the drawings, and in particular to  FIGS. 1-4 , a vascular puncture closure device  100  is shown according to the prior art. The vascular puncture closure device  100  includes a carrier tube  102  with a filament or suture  104  extending at least partially therethrough. The closure device also includes a first or proximal end  106  and a second or distal end  107 . External to a second or distal end  107  of the carrier tube  102  is an anchor  108 . The anchor is an elongated, stiff, low profile member including an eye  109  formed at the middle. The anchor  108  is typically made of a biologically resorbable polymer. 
     The suture  104  is threaded through the anchor  108  and back to a collagen sponge  110 . The collagen sponge  110  is slidingly attached to the suture  104  as the suture passes distally through the carrier tube  102 , but as the suture traverses the anchor  108  and reenters the carrier tube  102 , it is securely slip knotted proximal to the collagen sponge  110  to facilitate cinching of the collagen sponge  110  when the closure device  100  is properly placed and the anchor  108  deployed (see  FIG. 4 ). 
     The carrier tube  102  typically includes a tamping tube  112  disposed therein. The tamping tube  112  is slidingly mounted on the suture  104  and may be used by an operator to tamp the collagen sponge  110  toward the anchor  108  at an appropriate time to plug a percutaneous tissue puncture. Prior to deployment of the anchor  108  within an artery, the eye  109  of the anchor  108  rests outside the distal end  107  of the carrier tube  102 . The anchor  108  may be temporarily held in place flush with the carrier tube  102  by a bypass tube  114  disposed over the distal end  107  of the carrier tube  102 . 
     The flush arrangement of the anchor  108  and carrier tube  102  allows the anchor  108  to be inserted into an insertion sheath  116  as shown in  FIGS. 2-4 , and eventually through an arterial puncture  118 . The insertion sheath  116  is shown in  FIGS. 2-4  inserted through a percutaneous incision  119  and into an artery  128 . However, the bypass tube  114  ( FIG. 1 ) includes an oversized head  120  that prevents the bypass tube  114  ( FIG. 1 ) from passing through an internal passage of the insertion sheath  116 . Therefore, as the puncture closure device  100  is inserted into the insertion sheath  116 , the oversized head  120  bears against a surface  122  of insertion sheath  116 . Further insertion of the puncture closure device  100  results in sliding movement between the carrier tube  102  ( FIG. 1 ) and the bypass tube  114  ( FIG. 1 ), releasing the anchor  108  from the bypass tube  114  ( FIG. 1 ). However, the anchor  108  remains in the flush arrangement shown in  FIG. 1  following release from the bypass tube  114 , limited in movement by the insertion sheath  116 . 
     The insertion sheath  116  includes a monofold  124  at a second or distal end  126  thereof. The monofold  124  acts as a one-way valve to the anchor  108 . The monofold  124  is a plastic deformation in a portion of the insertion sheath  116  that elastically flexes as the anchor  108  is pushed out through the distal end  126  of the insertion sheath  116 . Typically, after the anchor  108  passes through the distal end  126  of the insertion sheath  116  and enters the artery  128 , the anchor  108  is no longer constrained to the flush arrangement with respect to the carrier tube  102  and it deploys and rotates to the position shown in  FIG. 2 . 
     Referring next to  FIGS. 3-4 , with the anchor  108  deployed, the puncture closure device  100  and the insertion sheath  116  are withdrawn together, depositing the collagen sponge  110  in the incision tract  119  and exposing the tamping tube  112 . With the tamping tube  112  fully exposed as shown in  FIG. 4 , the collagen sponge  110  is manually tamped, and the anchor  108  and collagen sponge  110  are cinched together and held in place with a self-tightening slipknot on the suture  102 . Thus, the tissue puncture  118  is sandwiched between and sealed by the anchor  108  and the collagen sponge  110 . The suture  104  is then cut and the incision  119  may be closed. The suture  104 , anchor  108 , and collagen sponge  110  are generally made of resorbable materials and therefore remain in place while the puncture  118  heals. 
     Using the typical tissue puncture closure device  100  described above, however, the tamping of the collagen sponge  110  cannot commence until the sheath  116  has been removed and the tamping tube  112  is exposed for manual grasping. Under certain conditions, removal of the sheath  116  prior to tamping the collagen sponge  110  causes the collagen sponge  110  to retract from the tissue puncture  118 , creating a gap  120  between the collagen sponge  110  and the puncture  118 . The gap  120  may remain even after tamping as shown in  FIG. 4 , and sometimes results in only a partial seal and bleeding from the tissue puncture  118 . In addition, excess tamping may cause the collagen sponge  110  to enter the artery. 
     Therefore, the present specification describes a tissue puncture closure device that enables tying sutures across punctures, rather than sandwiching punctures between internal and external components. As described above, the general structure and function of tissue closure devices used for sealing a tissue puncture in an internal tissue wall accessible through an incision in the skin are well known in the art. Applications of closure devices including those implementing principles described herein include closure of a percutaneous puncture or incision in tissue separating two internal portions of a living body, such as punctures or incisions in blood vessels, ducts or lumens, gall bladders, livers, hearts, etc. 
     Referring now to  FIGS. 5A-5B , a tissue puncture closure device, for example a vascular closure system  200 , is shown according to one embodiment of the present invention. The vascular closure system  200  has particular utility when used in connection with intravascular procedures, such as angiographic dye injection, cardiac catheterization, balloon angioplasty and other types of recanalizing of atherosclerotic arteries, etc. as the vascular closure system  200  is designed to cause immediate hemostasis of the blood vessel (e.g., arterial) puncture. However, it will be understood that while the description of the preferred embodiments below are directed to the closure of percutaneous punctures in arteries, such devices have much more wide-spread applications and can be used for closing punctures or incisions in other types of tissue walls as well. Thus, the sealing of a percutaneous puncture in an artery, shown herein, is merely illustrative of one particular use of the vascular closure system  200  of the present invention. 
     The vascular closure system  200  includes a central shaft or open-loop knot carrying device. According to the embodiment of  FIGS. 5A-5B , the open-loop knot carrying device is a carrier tube  201 . The carrier tube  201  has a first or distal portion  202  and a second or proximal portion  204 . The carrier tube  201  may be made of plastic or other material and is designed for insertion through a vascular access sheath such as insertion sheath  205 . The insertion sheath  205  is inserted into a percutaneous puncture such as an arteriotomy  206 , and into a bodily lumen  208 . According to  FIG. 5A , the lumen  208  comprises an interior portion of a femoral artery  210 . The carrier tube  201  includes an open slotted portion  212  disposed between the first and second portions  202 ,  204 . According to the embodiment of  FIG. 5A , the slotted portion  212  comprises first and second elongated slots  214 ,  216 . The first and second elongated slots are preferable arranged opposite of one another and comprise a width ranging between approximately 5 and 50 degrees of a circumference of the carrier tube  201 . As shown in  FIG. 5A , the open slotted portion  212  may also include third and fourth elongated slots  218 ,  220  of smaller width than the first and second elongated slots  214 ,  216 . The widths of the third and fourth elongated slots  218 ,  220  may be approximately equal to one another and range between 1 and 20 degrees of the circumference of the carrier tube  201 . The third and fourth elongated slots  218 ,  220  may be arranged opposite of one another as shown, preferably such that longitudinal centers of the first, second, third, and fourth elongated slots  214 ,  216 ,  218 ,  220  are spaced azimuthally from one another by, for example, approximately 90 degrees. 
     A filament such as a suture  222  extends from the first portion  202  to the second portion  204 , and, as shown in  FIGS. 5A-5B , the suture  222  may loop back to the first portion  204 . The suture  222  passes through a hole  224  in the first portion  202  and into the slotted portion  212 , with one branch  226  entering the slotted portion  212  through the first slot  214  and another branch  228  passing through the second slot  216 . The suture  222  is tied into first and second open loop knots  230 ,  232  that are shown spaced axially from one another and disposed at least partially within the slotted portion  212 .  FIG. 5B  illustrates the first and second open loop knots  230 ,  232  without the slotted portion  212  for clarity. A first portion  234  of the first open loop knot  230  and a first portion  236  of the second open loop knot  232  extend at least partially though the third slot  218 . Similarly, a second portion  238  of the first open loop knot  230  and a second portion  240  of the second open loop knot  232  extend at least partially through the fourth slot  220 . Accordingly, the first and second open loop knots  230 ,  232  are held in an open orientation with respect to the first and second elongated slots  214 ,  216 . The first and second open loop knots  230 ,  232  are preferably slip knots that are simultaneously closable or tightenable upon placing the suture  222  in tension. 
     The insertion sheath  205  also includes first and second side ports, for example first and second slots  242 ,  244 , arranged substantially opposite of one another and may be oval-shaped as shown in  FIG. 5A . According to the embodiment of  FIGS. 5A-5B , the first and second slots  242 ,  244  are adjacent, or within 1-5 cm, of the open slotted portion  212  when the carrier tube  201  is inserted through the insertion sheath  205 . 
     Referring next to  FIG. 6 , the first and second slots  242 ,  244  in the insertion sheath  205  facilitate passage of first and second cannula needles  246 ,  248 , respectively, therethrough. The first and second cannula needles  246 ,  248  may be have pointed or three-bevel tips as shown. The first and second slots  242 ,  244  in the insertion sheath  205  are aligned rotationally with respect to the first and second elongated slots  214 ,  216  of the slotted portion  212 . The first and second cannula needles  246 ,  248  diverge from one another and from the insertion sheath  205 . The first cannula needle  246  extends further than the second cannula needle  248  such that the first cannula needle  246  provides access to the first open loop knot  230  and the second cannula needle  248  provides access to the second open loop knot  232 . As shown in  FIG. 6 , the first and second cannula needles  246 ,  248  are insertable through the artery  210  flanking the arteriotomy  206 . 
     The first and second cannula needles  246 ,  248  allow passage of associated first and second curved needles  250 ,  252  therethrough as shown in  FIG. 7 . The first and second curved needles  250 ,  252  are preferably shape-memory needles. Therefore, each of the first and second curved needles  250 ,  252  is preferably made of a superelastic material such as nitinol and is capable of elastically deforming as it passes through the cannula needles  246 ,  248 . Accordingly, the first and second curved needles  250 ,  252  may straighten as each passes through its associated cannula needle  246 ,  248  and gains access to the bodily lumen  208 . However, as portions of the first and second curved needles  250 ,  252  exit the first and second cannula needles  246 ,  248 , they return to the curved configuration shown. A skilled artisan having the benefit of this disclosure will recognize that according to some embodiments, the first and second cannula needles  246 ,  248  may be omitted, and the first and second curved needles  250 ,  252  may pass directly through the first and second slots  242 ,  244  in the insertion sheath  205 . 
     Each of the first and second curved needles  250 ,  252  includes a step or shoulder  254 ,  256  at a distal end thereof. The curved shape of the first curved needle  250  facilitates extending the first curved needle  250  into the first elongated slot  214  of the slotted portion  212 , and at least partially through the first open loop knot  230 . The first curved needle  250  is inserted such that at least the shoulder  254  extends through the first open loop knot  230 . Likewise, the curved shape of the second curved needle  252  facilitates extending the second curved needle  252  into the second elongated slot  216  of the slotted portion  212 , and at least partially through the second open loop knot  232 . As with the first curved needle  250 , the second curved needle  252  is inserted such that at least the shoulder  256  extends through the second open loop knot  232 . 
     With the first and second curved needles  250 ,  252  inserted into the first and second open loop knots  230 ,  232 , respectively, the suture  222  may be placed in tension to tighten the knots around the needles as shown in  FIG. 8 . The first and second knots  230 ,  232  may be remotely tightened by a user pulling on free ends of the suture  222  to place the suture  222  in tension. Thus, the first and second curved needles  250 ,  252  grab the suture  222 . Free ends of the suture  222  may be accessible to an operator by extending the suture  222  from proximal areas of the carrier tube  201  and/or the insertion sheath  205 . 
     Once the first and second knots  230 ,  232  are tightened around the needles, the first and second curved needles  250 ,  252  may be retracted at least partially toward the first and second cannula needles  246 ,  248  as shown in  FIG. 9 . The first and second knots  230 ,  232  tend to bear against the shoulders  254 ,  256 , which prevent the suture  222  from slipping off of the first and second curved needles  250 ,  252 . The first and second curved needles  250 ,  252  may be fully retracted through the first and second cannula needles  246 ,  248 , or they may be refracted to the position shown in  FIG. 9  such that the first and second knots  230 ,  232  are arranged just outside of the first and second cannula needles  246 ,  248 . 
     Following retraction of the first and second curved needles  250 ,  252 , the first and second cannula needles  246 ,  248  may be simultaneously retracted with the first and second curved needles  250 ,  252  into the first and second slots  242 ,  244  in the insertion sheath  205  as shown in  FIG. 10 . Therefore, the suture  222  is also retracted through the insertion sheath  205  and through the small flanking holes in the artery  210  created by the cannula needles  246 ,  248  on either side of the arteriotomy  206 . The insertion sheath  205  and carrier tube  201  are further retracted from the arteriotomy  206  as shown in  FIG. 11 , which causes a looped portion  258  of the suture  222  to pass out of the carrier tube  201  and through the slotted portion  212 . Eventually, the looped portion  258  extends internally across the arteriotomy  206  as shown in  FIG. 12 . The vascular closure system  200  is finally removed from the arteriotomy  206  altogether, whereafter the suture  222  may be quickly cut and tied, immediately closing the arteriotomy  206  as shown in  FIG. 13 . 
     The preceding description has been presented only to illustrate and describe exemplary embodiments of invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the following claims. As used throughout the claims and specification, the words “including” and “having,” have the same meaning as the word “comprising.”

Technology Classification (CPC): 0