Abstract:
A tunneler assembly ( 100 ) for use with a catheter assembly ( 50 ), for securing the catheter assembly to a patient. The tunneler assembly includes a tunneler ( 102 ) and a connector assembly ( 110 ), the connector assembly being removably securable to the tunneler&#39;s proximal end ( 104 ) and also extending through the or one lumen ( 56 ) of the catheter to be engaged with the proximal end of the catheter assembly to push the catheter assembly forwardly through the newly created tunnel during performance of the tunneling procedure, after which the connector assembly ( 110 ) is removable to disconnect the tunneler ( 102 ) from the catheter. A connector section ( 114 ) on the proximal end ( 104 ) of the tunneler ( 102 ) enables an adapter ( 130 ) of the connector assembly to lock onto the tunneler, after which a sheath ( 160 ) is slid into position over the tunneler ( 102 ) and then over the connector assembly ( 110 ) to sheathe the connector assembly and adjacent portions of the catheter distal end ( 54 ) and the tunneler proximal end ( 104 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from U.S. Provisional Application Ser. No. 60/623,998 filed Nov. 1, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to the field of medical devices and more particularly to tunnelers for use with placement of catheters.  
       BACKGROUND OF THE INVENTION  
       [0003]     Certain medical procedures involve placement of a catheter into a patient where the catheter remains for a length of time in the patient, and such catheter placement procedures are well known. For chronic use, when the catheter is intended to remain in the patient for an extended period of time, and the proximal end of the catheter remains exposed outside the patient for connection to and disconnection from other medical devices for aspiration, for infusion of fluids, or especially for hemodialysis, it is crucially important that the implanted catheter, particularly its distal end, remain stabilized precisely in position in the blood vessel against all movement resulting from stress on the proximal catheter end. Furthering this purpose, the proximal catheter end outside of the blood vessel is secured in its position to the patient by known tunneling procedures; the catheter is typically tunneled into the patient prior to inserting the catheter into the patient&#39;s blood vessel. It is known to utilize a sheath positioned over the proximal tunneler end and the distal catheter end during tunneling.  
         [0004]     Catheters may be placed in various venous locations and cavity locations throughout the body of a patient for introduction of fluids to the body or removal of fluids from the body. Such catheterization may be performed by using a single catheter having multiple lumens, and a typical example of a multiple lumen catheter is a dual lumen catheter in which one lumen introduces fluid and the other lumen removes fluid. An example of such a multiple lumen catheter is the SPLIT STREAM™ catheter, manufactured by Medical Components, Inc. of Harleysville, Pa.  
         [0005]     Generally, to insert any catheter into a blood vessel, the vessel is identified by aspiration with a long hollow needle in accordance with the well-known Seldinger technique. When blood enters a syringe attached to the needle, indicating that the vessel has been found, a thin guide wire is then introduced, typically through a syringe needle or other introducer device into the interior of the vessel. The introducer device is then removed, leaving the end portion of the guide wire that has been inserted into the vessel within the vessel and the opposing end of the guide wire projecting beyond the surface of the skin of the patient. At this point, several options are available to a physician for catheter placement. The simplest is to pass a catheter into the vessel directly over the guide wire until the distal tip is precisely located along the vessel utilizing imaging apparatus. The guide wire is then removed, leaving the catheter in it desired position within the vessel. However, this technique is only possible in cases where the catheter is of a relatively small diameter, made of a stiff material, and not significantly larger than the guide wire. For example, this technique may be used to insert small diameter dual lumen catheters into a patient. If the catheter to be inserted is significantly larger than the guide wire, a dilator and sheath assembly is passed over the guide wire to enlarge the hole. The guide wire and dilator are then removed, and the catheter is then inserted through the sheath and into the vessel. The sheath is then removed by peeling the sheath from around the catheter while pulling the sheath from the vessel.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention is a tunneler assembly for use with a catheter assembly, the tunneler assembly having a tunneler and its sheath, and an adapter for removably connecting the tunneler to the catheter assembly for performing the tunneling procedure, whereafter the sheath and adapter are easily removed to disconnect the tunneler from the catheter assembly. The adapter includes an elongate portion that extends through the lumen of the catheter, or through a selected lumen of a multilumen catheter, from the proximal lumen end to and beyond the distal lumen end, where the protruding adapter distal end is coupled to the tunneler proximal end, whereafter the sheath is slid over the connection of the catheter assembly to the tunneler. The adapter proximal end removably connects to the proximal end of the catheter assembly and when pulled by the tunneler during tunneling, pushes the catheter assembly at its proximal end to follow the tunneler through the newly created tunnel.  
         [0007]     The adapter includes a distal connector section and a locking section on the distal connector section that releasably locks to a connector section on the proximal tunneler end. The adapter&#39;s distal connector section and the tunneler&#39;s connector section are shaped and dimensioned to fit within the sheath when locked together and the sheath pulled thereover. The adapter has an elongated, small diameter cylindrical body that is insertable through the selected catheter lumen until its proximal end protrudes beyond the proximal end of the catheter assembly. A plug is releasably securable onto the protruding proximal end portion of the adapter&#39;s cylindrical body to establish a releasable connection to the proximal end of the catheter assembly. Preferably, a stylet is utilized with the catheter assembly and includes a proximal end with a tapered entrance into which the plug on the adapter is pressed for performance of the tunneling procedure, to secure against axial movement of the tunneler assembly with respect to the catheter assembly. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention. In the drawings:  
         [0009]      FIG. 1  is a side profile view, partially in section, of a catheter tunneler assembly of the present invention, inserted into a catheter.  
         [0010]      FIG. 2  is an enlarged portion of  FIG. 1  showing a connection between a tunneler and adapter of the catheter tunneler assembly.  
         [0011]      FIG. 3  is an enlarged side profile view of the catheter tunneler shown in  FIG. 1 .  
         [0012]      FIG. 4  is an enlarged portion of  FIG. 3 , showing a proximal end of the tunneler.  
         [0013]      FIG. 5  is an enlarged side profile view of the adapter of  FIG. 2 .  
         [0014]      FIG. 6  is an end view of the adapter taken along lines  6 - 6  of  FIG. 5 .  
         [0015]      FIG. 7  is an enlarged side profile view of a plug securable to the adapter of FIGS.  1  to  6 ; and  
         [0016]      FIG. 8  is an end view of the plug taken along lines  8 - 8  of  FIG. 7 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     In the drawings, like numerals indicate like elements throughout. The terminology includes the words specifically mentioned, derivatives thereof and words of similar import. The embodiments illustrated below are not intended to be exhaustive or to limit the invention to the precise form disclosed. The word “proximal” as used herein, is defined to mean the direction closer to the end of a catheter that is connected to an external device, shown as the left hand side of the catheter  52  in  FIG. 1 . The word “distal” as used herein, is defined to mean the direction closer to the end of the catheter that is inserted into a patient&#39;s blood vessel, shown as the right hand side of the catheter  52  in  FIG. 1 . Regarding tunneler  102 , the left hand side is denoted herein as the proximal end, and the right hand side as the distal end. These embodiments are chosen and described to best explain the principle of the invention and its application and practical use and to enable others skilled in the art to best utilize the invention.  
         [0018]     Referring first to  FIG. 1 , catheter assembly  50  includes catheter  52  having at least one lumen and a distal catheter end  54 , and a catheter tunneler assembly  100  according to the preferred embodiment of the present invention is shown secured to the distal catheter end  54 . In  FIG. 1 , catheter  52  is shown having two lumens, an arterial lumen  56  and a venous lumen  58 . The catheter assembly also is shown having a hub  60  that secures extension tubes to the catheter, the extension tubes respectively having clamps and luer caps thereon, and also a stylet  62  that is removably secured to the luer cap affixed to the proximal end of the arterial lumen  56 .  
         [0019]     Catheter tunneler assembly  100  is used to connect to the distal end of the catheter of catheter assembly  50  to pull it through a subcutaneous tunnel during catheter insertion into a patient. The tunneler assembly  100  includes a tunneler  102  and a connector assembly  110  on its proximal end  104 .  
         [0020]     Referring now to  FIGS. 1 and 3 , the tunneler  102  includes an elongated, generally cylindrical body  106  having a distal tip  108 . The body  106  preferably bends at a predetermined location along its length; as shown in  FIGS. 1 and 3 , the body  106  is bent at an angle β 1  of approximately 12 degrees, although those skilled in the art will recognize that it may be bent more or less than 12 degrees or have no bend at all. The distal tip  108  is preferably blunt, and is inserted into the tunnel after a separate tunneling device (not shown) has been used to form the tunnel. Alternatively, those skilled in the art will recognize that the distal tip  108  may include a sharp point so that the tunneler  102  may be used to form the tunnel.  
         [0021]     In reference to FIGS.  2  to  4 , the proximal end  104  of the tunneler  102  includes a generally frusto-conical retainer  112  that is used to retain the sheath  160  onto the tunneler  102  during use. A connector section  114  extends proximally from the retainer  112  and is used to retain the adapter  130  onto the tunneler  102 . The retainer  112  includes a cylindrical elongated member  114  having a passageway  116  extending partially thereinto that preferably includes a tapered portion  118  that extends at least partially through the passageway  116  and is shown to conclude in a narrowed inner portion  120 . A proximal end of the elongated member  114  includes an enlarged portion  122  having a distal lip  124  that is used to connect the tunneler  102  to the adapter  130 . Preferably, the tunneler  102  is constructed from stainless steel, although those skilled in the art will recognize that other suitable materials may be used.  
         [0022]     Referring to  FIGS. 2, 5  and  6 , the adapter  130  includes a distal portion  132 , shown to be shaped in the general form of a trident. The distal portion  132  is fixedly connected to an elongated cylindrical body  134  and includes a central prong  136  that includes a tapered portion  138 . The central prong  136  and the tapered portion  138  are sized to fit snugly within the passageway  122  in the tunneler  110 .  
         [0023]     The distal adapter portion  132  also includes a plurality of gripping fingers  140  that extend generally parallel to the central prong  136  and spaced laterally therefrom. Preferably, two gripping fingers  140  are used, although those skilled in the art will recognize that more than two gripping fingers  140  may be used. Each gripping finger  140  includes an inwardly facing tapered face  142  that extends proximally toward the central prong  132  for engaging and camming over enlarged portion  122  of tunneler connector section  114  which temporarily deflects the gripping fingers  140  outwardly to pass thereover. Each gripping finger  140  also includes a locking surface  144  that extends proximally of the tapered face  142  and is generally perpendicular to the central prong  136 . Each locking surface  144  is adapted to lockingly engage with the distal lip  124  of the enlarged portion  122  ( FIG. 4 ) on the tunneler  102  to retain the adapter  130  onto the tunneler.  
         [0024]     While the gripping fingers  140  are preferably used to connect the adapter  130  to the tunneler  102 , those skilled in the art will recognize that other connection methods, such as threaded connections, barbs, and other known connection means may be used to connect the adapter  130  to the tunneler  102 .  
         [0025]     The cylindrical body  134  is preferably connected to the distal portion  132  by solvent bonding, overmolding, or some other suitable method known by those skilled in the art. Preferably, the distal portion  132  is constructed from nylon or some other suitable material. The cylindrical body  134  is small in diameter and is preferably constructed from nylon or some other suitable material that allows the cylindrical body  134  to flex as the cylindrical body  134  is inserted through the selected lumen of catheter  52  from its distal tip until the proximal and exits from the proximal end of catheter assembly  50  beyond the luer cap on the extension sleeve for the selected lumen.  
         [0026]     A plug  146  is shown in  FIGS. 1, 7  and  8  and includes a generally frusto-conically shaped body  148  having a through passage  150  extending axially therethrough and having a slot  152  that extends the length of the body  148  from the through passage  150  to the exterior of the body  148 . Slot  152  is sized to allow the cylindrical body  134  of the adapter  130  to be inserted thereinto from laterally thereof until seated within through passage  150 .  
         [0027]     Referring back to  FIGS. 1 and 2 , the sheath  160  includes a generally tubular sheath body  162  having a distal end  164  and a proximal end  166 . A through passage  168  extends between the distal end  164  and the proximal end  166 . The distal end  164  is tapered, with the through passage  168  having a corresponding taper. The taper in the through passage  168  corresponds with the frusto-conical retainer  112  so that the sheath  160  engages the retainer  112  and prevents the sheath  160  from further sliding proximally thereof. Additionally, the sheath body  162  is sufficiently long to completely encase the distal portion  132  of the adapter  130  as well as the distal ends of the catheter lumens in the catheter  52 , as shown in  FIG. 1 . Preferably, the sheath  160  is constructed from polypropylene or some other suitable material.  
         [0028]     In use, referring to  FIG. 1 , a stylet  62  is used with the catheter assembly and is inserted from the proximal end of the catheter assembly  50  into the arterial lumen  56 . Preferably, the stylet  62  extends exterior of the distal end of the arterial lumen  56  and distally of the distal end of the venous lumen  58 . The stylet  62  includes an axial passage extending therethrough that is sized to allow the cylindrical body  134  of the adapter  130  to pass therethrough. The cylindrical body  134  is sufficiently long such that the cylindrical body  134  extends through the stylet&#39;s axial passage and out the proximal end thereof.  
         [0029]     The plug  146  is placed onto the proximal end of the cylindrical body  134  after the cylindrical body  134  is passed through the stylet&#39;s axial passage and the cylindrical body&#39;s proximal end portion protrudes beyond the stylet. The plug is then advanced and pressed into the stylet  62 , compressing the slot  152  so that the plug  146  engages and restricts the cylindrical body  134  from movement. The slot  152  allows the plug  146  to be compressed to grip tightly the cylindrical body  134  of the adapter  130  when the plug  146  is inserted into the stylet  62 . Preferably, the plug  146  is constructed from an elastomer, such as a KRATON® polymer, or some other suitable material that allows the plug  146  to deform under compression without fracture.  
         [0030]     The connector section  114  ( FIGS. 1 and 2 ) on the tunneler  102  is connected to the distal portion  132  of the adapter  130  by inserting the central prong  136  of the distal portion  132  into the passageway  116  in the connector section  114 . The central prong  136  is advanced sufficiently into the connector section  114  so that the tapered portion  138  of the central prong  136  bottoms out against the tapered portion  118  of the passageway  116 . Generally simultaneously, the tapered face  142  of each gripping finger  140  engages the enlarged portion  122  on the connector section  114 , biasing the gripping fingers  140  outward. As the gripping face  144  of each gripping finger  140  passes distally of the distal lip  124 , the gripping fingers  140  resile back toward their original undeflected positions, locking the tunneler  102  onto the adapter  130 .  
         [0031]     Next, the sheath  160  is first inserted over the distal tip  108  of the tunneler so that the distal tip  108  of the tunneler  102  enters the proximal end  162  of the sheath  160 , passes through the through passage  168  and out the distal end  164  of the sheath  160 . The sheath  160  is advanced proximally along the tunneler  102  until the retainer  112  engages the inside surface of the tapered distal end  164  of the sheath  160 . Sheath  160  will hold the adapter latch arms in place locked to the tunneler proximal end during tunneling.  
         [0032]     The catheter  52  is now ready to be tunneled according to known techniques with the plug of the adapter pushing the catheter assembly through the newly made tunneler and following the tunneler. After tunneling, the plug  146  is removed from the stylet  62 , allowing the through passage  150  to open up and release the cylindrical body  134  of the adapter  130  whereafter the remaining part of the tunneler assembly  100  is advanced distally from the stylet  62  and the catheter  52  and discarded. Alternatively, the cylindrical adapter body  134  may be severed distally of the catheter&#39;s distal tip  54 , and the plug  146  remains secured to the cylindrical body  134  proximal end portion and facilitates proximal removal of the cylindrical body from the catheter assembly. The catheter  52  may now be inserted into the patient&#39;s blood vessel according to known techniques.  
         [0033]     While the catheter  52  shown in  FIGS. 1 and 2  is a side-by-side dual lumen catheter, those skilled in the art will recognize that the tunneler assembly  100  of the present invention may be used with single lumen catheters and catheters having more than two lumens, as well as co-axial catheters.  
         [0034]     While the above disclosure uses the stylet  62  to assist in the insertion of the catheter  52  into the patient, those skilled in the art will recognize that the stylet  62  may also be omitted, with the plug  146  being inserted directly into the cap on the proximal end of the extension tube for the arterial lumen  56 .  
         [0035]     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claim.