Patent Publication Number: US-2006015130-A1

Title: Catheter tunneler adapter

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This relates to and claims priority from Provisional U.S. Patent Application Ser. No. 60/587,679 filed Jul. 14, 2004. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates to a tunneler device for subcutaneously tunneling a catheter under a patient&#39;s skin prior to insertion into a patient&#39;s blood vessel.  
     BACKGROUND OF THE INVENTION  
      Catheters for the introduction or removal of fluids may be located in various venous locations and cavities 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. 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.  
      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. The guide wire is then removed, leaving the catheter in 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.  
      For chronic catheterization, in which the catheter is intended to remain inside the patient for an extended period of time, such as for weeks or even months, it is typically desired to subcutaneously tunnel the catheter using various tunneling techniques. The catheter is typically tunneled into the patient prior to inserting the catheter into the patient&#39;s vein.  
     SUMMARY OF THE INVENTION  
      The present invention comprises a catheter tunneler assembly used to tunnel a distal end of a multilumen catheter assembly through a subcutaneous tunnel prior to inserting the catheter assembly into a patient. A distal end of the assembly includes a tunneler, such as a trocar, and an adapter that facilitates connection of the trocar with the catheter assembly and provides a smooth transition between the trocar&#39;s proximal end and the catheter assembly. The adapter is also adapted to restrict movement of the catheter assembly away from the tunneling assembly. The adapter comprises an inner member having a trocar gripping section and a catheter engagement section, and an outer member slidable from distally of the inner member to a position surrounding the inner member and an end portion of the catheter assembly. The outer or sheath member is adapted to press the adapter inner member projection toward the tunneler projection so that a catheter lumen wall is frictionally held therebetween.  
      In a preferred embodiment, the adapter inner member is affixed to the proximal end of the tunneler in a manner exposing a projection of the tunneler for insertion into a first lumen of the catheter assembly, and further includes a projecting portion coextending along and spaced from the tunneler projection to coextend along and adjacent to an inner, second lumen of the catheter assembly. The outer member is adapted to be slid over the adapter inner member and over both the tunneler projection after being positioned within the first lumen of the catheter assembly, and the adapter projection that extends along and adjacent the catheter assembly inner lumen, so that a proximal portion of the outer adapter member extends beyond the inner member&#39;s adapter projection to surround an adjacent end portion of the catheter assembly.  
      The present invention also includes a method for connecting a catheter assembly to a tunneling assembly, having the steps of: providing a catheter having at least one lumen; providing a catheter tunneler assembly having a proximal end body, a first extension, a second extension spaced laterally from the first extension, and a slider; inserting the first extension into the at least one lumen of the catheter; and, sliding the slider along the body toward the catheter to surround the proximal end body and the first and second extensions and a distal catheter end portion to bias the second extension toward the first extension into frictional engagement with a catheter portion therebetween.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate the presently preferred embodiment 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:  
       FIG. 1  is a side profile view of a catheter tunneler assembly comprised of a catheter tunneler and adapter according to an embodiment of the present invention;  
       FIG. 2  is a side profile view of the catheter tunneler shown in  FIG. 1 ;  
       FIG. 3  is an enlarged end view of the catheter tunneler assembly shown in  FIG. 1 ;  
       FIG. 4  is a side profile view of the adapter of the catheter tunneler assembly shown in  FIG. 1 ;  
       FIG. 5  is an enlarged end view of the adapter taken along lines  5 - 5  of  FIG. 4 ;  
       FIG. 6  is an enlarged view of the proximal end of the adapter shown in  FIG. 5 ;  
       FIG. 7  is a sectional view of the tunneler assembly taken along line  7 - 7  of  FIG. 1 ;  
       FIG. 8  is and end view of a tunneler grasper sheath for use with the tunneler assembly;  
       FIG. 9  is a longitudinal sectional view of the tunneler grasper sheath taken along line  9 - 9  of  FIG. 8 ;  
       FIG. 10  is a side profile view of the catheter tunneler assembly of  FIG. 1 , connected to the distal end of a catheter; and  
       FIG. 11  is an enlarged perspective view, in section, of the tunneler assembly and grasper sheath connected to the distal end of a catheter.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      In the drawings, like numerals indicate like elements throughout. Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. When describing or referring to the catheter tunneler adapter, the words “proximal” and “distal” refer to directions away from and closer to, respectively, the pointed tip of the trocar that makes up a portion of the catheter tunneling assembly according to the present invention. When describing or referring to a catheter, the words “proximal” and “distal” refer to directions away from and closer to, respectively, the tip of the catheter that is inserted in the blood vessel closest to the patient&#39;s heart. The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. The following describes a preferred embodiment of the invention. However, it should be understood based on this disclosure, that the invention is not limited by the preferred embodiment described herein.  
      Referring to  FIG. 1 , a side profile view of a catheter tunneling assembly  100  according to a preferred embodiment of the present invention is shown. Preferably, the catheter tunneling assembly  100  is used to tunnel a distal end of a multilumen catheter assembly through a subcutaneous tunnel prior to inserting the catheter assembly into the patient. Those skilled in the art will recognize that the assembly  100  may be used to tunnel the proximal end of a multilumen catheter, or either end of a single lumen catheter, without departing from the scope of the present invention.  
      The tunneling assembly  100  includes a distal portion, or tunneler, such as a trocar  110  and an adapter having an inner body or gripper  130  and an outer member or slider or grasping sheath  160  that can be disposed over the body. The adapter inner body  130  facilitates connection of the trocar  110  with the catheter assembly and provides a smooth transition between a proximal end  114  of the trocar  110  and the catheter assembly to minimize tearing or snagging of subcutaneous tissue during catheter tunneling. Additionally, the adapter serves to restrict the movement of the catheter assembly away from the tunneling assembly  100 .  
      Referring now to  FIG. 2 , the trocar  110  includes a distal tip  112 , the proximal end  114 , and a longitudinal axis  116  extending through the proximal end  114 . A longitudinal plane “P 1 ” extends along the longitudinal axis  116  perpendicular to the plan of the paper containing  FIG. 2 . An elongated body  118  extends between the distal tip  112  and the proximal end  114 . The body  118  is preferably approximately 3.7 mm in diameter and tapers to a distal tip  112  that may be either blunt or sharp. The body also preferably bends at a predetermined location along the length of the body  118 . As shown in  FIG. 2 , the body  118  is bent at an angle β 1  of approximately 16 degrees, although those skilled in the art will recognize that the body  118  may be bent more or less than 16 degrees or have no bend at all. Preferably, the trocar  110  is of unitary construction and is preferably constructed from  303  stainless steel, although those skilled in the art will recognize that the trocar  110  may be constructed from other suitable materials.  
      The proximal end  114  includes a tapered ring  120  that increasingly tapers in a proximal direction from a diameter of the body  118  to a slightly larger diameter, such as approximately 0.5 mm, than that of the body  118 . A circumferential channel  122  is disposed distally of the ring  120 . The channel  122  is used to positively secure the adapter  130  to the trocar  110 , as will be explained in more detail later herein. A locking ring  124  is disposed proximally of the channel  122 . Preferably, the distal ring  124  is the same diameter as the tapered ring  120 .  
      A first projection or catheter insert prong  126  is disposed proximally of the distal ring  124 . As seen in  FIG. 3 , the insert prong  126  has a generally C-shaped or semi-annular profile and is disposed on one side of the longitudinal plane P 1 . The insert prong  126  is shown to be configured to fit into the distal tip of a lumen of a multi-lumen catheter, such as the TORRENT FLOW™ catheter manufactured by Medical Components, Inc. of Harleysville, Pa. Although insert prong  126  is shown as generally C-shaped in profile, those skilled in the art will recognize that any shape suitable to be inserted into the distal tip of a catheter lumen may be used.  
      Referring to  FIG. 4 , the adapter inner body  130  includes a generally elongated body  132  having a proximal portion  134  and a distal portion or second projection  136 . A connector or hinge  137  connects the proximal portion  134  and the distal portion  136 . The connector  137  has a smaller cross-sectional size than the proximal portion  134  or the distal portion  136  to provide some flexibility between the proximal portion  134  and the distal portion  136 .  
      A longitudinal axis  138  extends through the body  132  between the proximal portion  134  and the distal portion  136 . A longitudinal plane “P 2 ” extends along the longitudinal axis  138  perpendicular to the plan of the paper containing  FIG. 4 . The proximal portion  134  extends wholly on one side of the longitudinal plane P 2 , and preferably it is angled slightly away from plane P 2  to facilitate insertion of the tunneler assembly onto the catheter end. As seen in  FIG. 5 , the proximal portion  134  has a generally semi-annularly shaped cross-section, with an inwardly directed surface having a curved face  139  and generally flat elongated longitudinal portions  140  on either side of the curved face  139 .  
      As seen in  FIG. 6 , each longitudinal portion  140  includes a plurality of ribs  142  that extend transverse to the length of the proximal portion  134 . Each rib  142  has a distal face  144  that extends perpendicular to the longitudinal portion  140  and a proximal face  146  that extends at an angle β 2  from the perpendicular. Preferably, P 2  is approximately 45 degrees, although those skilled in the art will recognize that β 2  may be more or less than 45 degrees.  
      Referring to  FIGS. 4 and 7 , the distal portion  136  includes a hollow tapered distal end  148  and a generally hollow cylindrical body  150 . The taper of the distal end  148  is preferably approximately 12 degrees. As seen in  FIG. 7 , the proximal end  152  of the body  150  is closed.  
      Adapter body  130  is constructed from HDPE and is overmolded over the proximal end  114  of the trocar  110 . The overmold process disposes HDPE into the channel  122 , as seen in  FIG. 7 . The HDPE within the channel  122  provides a positive lock of the adapter inner body  130  onto the proximal end  114  of the trocar  110  so that the adapter inner body will not be separated from the trocar  110  during catheter tunneling. The overmold process also forms the distal end  136  of the adapter inner body with a taper having a taper angle β 3  of approximately 12 degrees.  
      Referring now to  FIGS. 8 and 9 , an adapter slider or outer member or grasper sheath  160  is shown. As seen in  FIG. 9 , the grasper sheath  160  is generally tubular in shape, with a tapered proximal end  162  and a tapered distal end  164 . Preferably, the distal end  164  is tapered at an angle β 4  that is equivalent to angle β 3 . Grasper sheath  160  is sized to allow the trocar  110  and the adapter inner body  130  to be inserted through its proximal end  162  and pulled through the distal end  164  having an inner diameter D 1 . Preferably, the inner diameter D 2  at proximal end  162  is dimensioned to match the catheter&#39;s outer diameter. Preferably, also, the grasper sheath  160  is constructed from polypropylene.  
      In use, the tunneling assembly  100  is engaged with the distal end of a catheter  200 , as shown in  FIG. 10 . The catheter  200  has a first lumen  202 , a second lumen  204 , and a third or inner lumen  206  and has an outer diameter D 3 . Such a catheter  200  is the TORRENT FLOW™ catheter. In cross-section, the lumens  202 ,  204  are each generally C-shaped and juxtaposed from each other across a plane, and the third lumen  206  is generally circular and is centered between the first and second lumens  202 ,  204 . The catheter insert prong  126  is inserted in the distal end of the first lumen  202  until the distal end of the third lumen  206  engages the proximal end  152  of the hollow cylindrical body  150  of the adapter body  130 . The curved face  139  of the proximal portion  134  is sized and shaped to fit over the exterior of the third, inner lumen  206  distal of the second lumen  204 . Connector  137  preferably is shaped to dispose the proximal end  134  of the adapter  130  slightly away from the catheter  200 , and the overall width of the assembly at the tip of proximal end  134 , including the catheter  200 , is designated as W, which is greater than D 3 . Inner diameter D 2  of outer adapter member at its proximal end  162 , as stated hereinabove, is less than W.  
      After the tunneling assembly  100  is inserted onto the distal end of the catheter  200 , the distal tip  112  of the trocar  110  is inserted into the proximal end  162  of the grasper sheath  160 , through the grasper sheath  160  and out the distal end  164  of the grasper sheath  160 . The grasper sheath  160  is slid proximally along the trocar  110  and the adapter inner body  130  until the tapered distal end  164  of the grasper sheath  160  engages its tapered distal end  148 . As shown in  FIG. 11 , the proximal end  162  of the grasper sheath  160  engages the proximal end  134  of the adapter inner body  130  and pivots the proximal end  134  of the adapter inner body toward the catheter to be biased against the exterior of the first lumen  202  so that the ribs  142  at least slightly dig into the exterior of the first lumen  202  to provide a secure engagement of the adapter body  130  with the catheter  200 .  
      After the tunneling assembly  100  is secured to the catheter  200  as described above, the catheter  200  is tunneled according to known procedures. After tunneling, the grasper sheath  160  is slid distally along the trocar  110  until the proximal end  134  of the adapter inner body  130  is freed from the grasper sheath  160 . The proximal end  134  then again is angled by the connector  137  to space the ribs  142  from the exterior of the first lumen  202  to facilitate disassembly of the tunneler from the catheter. The catheter insert prong  126  is removed from the distal end of the catheter  200  and the tunneling assembly  100 , with grasper sheath  160 , may be discarded.  
      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 claims.