Abstract:
A method and apparatus for facilitating the management of indwelling conduits to avoid and/or treat infections associated with long term implantation. A sleeve carrying a layer of porous material on its outer surface is percutaneous implanted to place the layer of porous material just under the patient&#39;s outer skin in contact with the patient&#39;s dermis where it functions to promote soft tissue ingrowth. A catheter passes through the sleeve passageway and along an interior body path to an interior destination site, e.g., an opening into a vein, i.e., venotomy site. Within about 3-6 weeks after implantation, the patient&#39;s dermal tissue integrates sufficiently with the sleeve porous material to physically anchor the sleeve and create an infection resistant barrier. Further, a tunnel, characterized by an epithelialized capsule, typically forms around the catheter along the interior body path extending to the interior destination site. After sufficient integration of the patient&#39;s soft tissue into the porous layer, the sleeve passageway can be used to pass various procedural tools to the tunnel and interior destination site without disturbing the tissue integrating barrier.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a Continuation-In-Part of U.S. application Ser. No. 11/708,445 filed on Feb. 20, 2007 which claims priority based on U.S. Provisional Application 60/818,768 filed on Jul. 5, 2006. This application also claims priority based on U.S. Provisional Application 60/998,848 filed on Oct. 12, 2007. The aforementioned applications are, by reference, incorporated herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates generally to medical technology and more particularly to a method and apparatus for facilitating the management of indwelling conduits, e.g., catheters, to avoid and/or treat infections which often occur as a consequence of the conduit being implanted for long periods of time, e.g., greater than 30 days. Embodiments of the invention are useful in a variety of applications which employ percutaneous conduits, e.g., in hemodialysis procedures where a percutaneous catheter provides fluid access to a patients central venous system and/or nerve stimulation procedures in which a percutaneous cable provides access to an implanted electric device. 
       BACKGROUND OF THE INVENTION 
       [0003]    For a variety of medical procedures, a conduit, most typically a catheter, is implanted in a patient so that it extends through a skin incision and along an interior path to an interior destination site; e.g., a venotomy site. When a catheter remains implanted over a long period, e.g., greater than 30 days, infections frequently occur, generally at the incision site where the catheter enters the body or along the interior path, or tunnel, or at the destination site, e.g., the entrance point to a vein. These problems are widely discussed in the literature; e.g., see “Long-Term Management Of The Tunneled Venous Catheter” by Liangos et al, Seminars In Dialysis 19(2) 158-164. 
         [0004]    The aforementioned U.S. application Ser. No. 11/708,445 describes an apparatus and method of use for percutaneously implanting an elongate conduit, e.g., a catheter or cable, in a patient&#39;s body in a manner which allows the conduit to be easily positioned, repositioned, and replaced. Briefly, the exemplary apparatus described in said application Ser. No. 11/708,445 includes an elongate sleeve designed to be implanted for very long periods, e.g., several months to years. The sleeve comprises a wall surrounding an interior elongate passageway which extends from a sleeve proximal end to a sleeve distal end. The sleeve is intended to be percutaneously implanted through an incision in the patient&#39;s skin so that the sleeve distal end resides beneath the skin, i.e., subcutaneously, and the sleeve proximal end resides outside the skin. The sleeve outer peripheral surface carries a layer of porous material, e.g., a biocompatible mesh, intended to be placed under the patient&#39;s outer skin layer in contact with the dermis to promote tissue ingrowth for anchoring the sleeve and forming an infection resistant barrier. The sleeve passageway is dimensioned to snugly accommodate the outer surface of a conduit (which will hereinafter be assumed to be a catheter unless otherwise stated) while permitting the catheter to slide and rotate in the passageway relative to the sleeve. A sealing device within the sleeve extends around the catheter, e.g., near the sleeve proximal end, to prevent infectious material from migrating into the patient&#39;s body along the catheter outer surface. 
         [0005]    A locking member mounted at the sleeve&#39;s proximal end is configured so it can be readily manipulated by a physician to selectively define either a first, or unlocked, state, and a second, or locked, state. In the unlocked state, the catheter is able to slide and/or rotate relative to the sleeve passageway. In the locked state, a friction force is applied to the catheter to prevent relative movement between the catheter and the sleeve. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is directed to a method and apparatus for facilitating the management of indwelling conduits to avoid and/or treat infections associated with long term implantation. 
         [0007]    In accordance with the present invention, a sleeve, for example of the type described in said application Ser. No. 11/708,445, carrying a layer of porous material on its outer surface is percutaneously implanted to place the layer of porous material just under the patient&#39;s skin in contact with the patient&#39;s dermis where it functions to promote soft tissue ingrowth. A catheter passes through the sleeve passageway and along an interior body path to an interior destination site, e.g., an opening into a vein, i.e., venotomy site. Within about 3-6 weeks after implantation, the patient&#39;s dermal tissue integrates sufficiently with the sleeve porous material to physically anchor the sleeve and create an infection resistant barrier. Further, a tunnel, characterized by an epithelialized capsule, typically forms around the catheter along the interior body path extending to the interior destination site. After sufficient integration of the patient&#39;s soft tissue into the porous layer, the sleeve passageway can be used, in accordance with the invention, to pass various procedural tools to the tunnel and interior destination site without disturbing the tissue integrating barrier. The procedural tools can be used for a variety of purposes. For example, the tools can include a balloon catheter for treating thrombosis or stenosis and for implanting a vascular stent, an angiography catheter for introducing contrast media, an infusion catheter for introducing medication, etc. 
         [0008]    To prevent outward blood flow when inserting tools into the sleeve, it is preferable to provide a hemostatic valve connected in series with the sleeve passageway. In an exemplary embodiment, the hemostatic valve can be mounted within the sleeve passageway. In a preferred embodiment, a portal device is provided having at least one lumen whose distal end is adapted for detachable coupling to the proximal end of the sleeve. The portal device includes an entrance port at the lumen proximal end. An adjustable hemostatic valve, e.g., Touhy-Borst, is preferably detachably coupled to the portal device entrance port. The portal device preferably also incorporates a closure device, or cap, for temporarily closing the lumen to seal the passageway and tunnel. 
         [0009]    It is generally known that an epithelialized capsule, or tunnel, typically forms around a long term hemodialysis catheter. Inasmuch as preservation of the tunnel and venotomy site is often considered important to the long term success of a procedure, it is frequently advantageous to remove an implanted catheter for a short period, e.g., 24 to 72 hours, to facilitate the treatment of an infection in the tunnel or near the venotomy site or in the bloodstream. Embodiments of the invention allow for a catheter to be withdrawn from the sleeve to allow the infection to be treated by infusing antibiotics or other agents into the tunnel, and for subsequently reinserting a new catheter through the sleeve passageway and tunnel. The sleeve and tunnel will often guide the catheter to the venotomy site and into the blood vessel to reestablish vascular access without requiring a major interventional procedure. Moreover, the foregoing can be performed without disrupting the tissue integrity barrier formed at the sleeve porous layer. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIG. 1  is a schematic representation generally depicting a catheter assembly used in accordance with the invention for percutaneously implanting a catheter for an exemplary hemodialysis application; 
           [0011]      FIG. 2  is an isometric view of a preferred catheter assembly; 
           [0012]      FIG. 3  is an exploded view of the assembly of  FIG. 2  showing a catheter in phantom together with a protective sheath, an anchor, a sleeve carrying a layer of porous material, an annular seal, and a locking member; 
           [0013]      FIG. 4A  is a sectional view taken substantially along the plane of  4 A- 4 A of  FIG. 2 ; 
           [0014]      FIG. 4B  is a sectional view taken substantially along the plane  4 B- 4 B of  FIG. 4A  showing the locking member in its unlocked state; 
           [0015]      FIG. 4C  is a sectional view similar to  FIG. 4B  showing the locking member in its locked state clamped by suture or wire; 
           [0016]      FIGS. 4D and 4E  show exemplary spring clips which can be alternatively used for clamping the locking member in its locked state; 
           [0017]      FIG. 5  is a plan view of the protective sheath of  FIG. 3 ; 
           [0018]      FIG. 6  is a sectional view taken substantially along the plane  6 - 6  of  FIG. 5  particularly showing a perforated score line; 
           [0019]      FIG. 7  is an isometric view of a preferred portal device in accordance with the present invention; 
           [0020]      FIG. 8  is a side view of the portal device of  FIG. 7 ; 
           [0021]      FIG. 9  is a plan view of a commercially available Touhy-Borst hemostatic valve assembly which can be used in combination with the portal device of  FIG. 7 ; and 
           [0022]      FIG. 10  shows an exemplary procedural tool (i.e., angioplasty balloon) inserted through the hemostatic valve, portal device, and sleeve for accessing an interior body site. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Various medical regimens relating, for example, to hemodialysis drug infusion, plasmapheresis, etc., use a percutaneously implanted conduit for conveying fluid and/or electric signals to/from an interior body site. The present invention is directed to a method and apparatus for facilitating the management of a percutaneous conduit (e.g., catheter) intended for use over a long term, e.g., greater than 30 days. A preferred embodiment of the present invention utilizes apparatus of the type exemplified by said U.S. application Ser. No. 11/708,445. For convenience,  FIGS. 1-6  of this application duplicate the corresponding figures of said application Ser. No. 11/708,445 but it should be understood that the present invention is not restricted to the use of this particular apparatus. 
         [0024]      FIG. 1  schematically depicts an assembly  20  for percutaneously implanting a catheter  22  through an incision  24  in a patient  26  undergoing an exemplary hemodialysis procedure. In such a procedure, a dual lumen catheter  22  is typically used with the two lumens being respectively coupled to separate exterior flow couplers  28  and  29 . 
         [0025]    Attention is now directed to  FIGS. 2-4  which show the primary elements of the assembly  20  including sleeve  30  carrying a porous layer  31 , a sealing device  32 , and a locking member  33 . The assembly  20  also preferably includes an optional removable protective sheath  34  and an anchor  35  for anchoring the assembly  20  to a patient&#39;s outer skin surface. The sleeve  30  preferably comprises a substantially rigid tubular member formed of biocompatible material, e.g., titanium. The sleeve  30  includes a peripheral wall  36  ( FIG. 4 ) having an outer surface  37  and an inner surface  38 . The inner surface  38  surrounds an interior passageway  39  extending axially from a sleeve first, or proximal, end  40  to a sleeve second, or distal, end  42 . 
         [0026]    The sleeve  30  is shown mounted on a catheter  22  extending axially through the passageway  39 . The catheter outer surface  44  and passageway wall surface  38  are closely dimensioned but with sufficient clearance therebetween to enable the catheter to slide axially and rotate in the passageway  39 . The sleeve  30  proximal end  40  is preferably enlarged at  45  to form an interior recess  46  for accommodating the sealing device  32 . The sealing device  32  preferably comprises an annular member  48  formed of a soft flexible material, e.g., silicone. The seal member  48  defines an inner peripheral surface  50  surrounding an interior bore  52  which is contiguous with sleeve passageway  39 . At least one flexible annular nib  54  extends radially into the bore  52  for contacting and sealing against the catheter outer surface  44 . 
         [0027]    The enlarged sleeve end  45  has an outer peripheral surface  56  dimensioned to closely fit into bore  58  of anchor  35 . The anchor  35  comprises a base portion  60  supporting a ferrule portion  62  which defines the bore  58 . The anchor base portion  62  is provided with holes  64  to facilitate the suturing of anchor  35  to the patient&#39;s skin. 
         [0028]    The locking member  33  preferably comprises a split ring formed of soft flexible material, e.g., silicone. More particularly, the locking member  33  is comprised of a peripheral wall  66  having an outer surface  68  and an inner surface  70  surrounding an interior bore  72 . The wall  66  is longitudinally split at  74 . The wall outer surface  68  is preferably provided with one or more strap pads  71  for securing the locking member  33  to the anchor  35  and/or sleeve  30  using one or more straps  76 . The locking member outer wall surface is provided with a proximal annular groove  80  for accommodating suture thread or an appropriately shaped spring clip which can be used by a physician to compress the locking member  33  around the catheter  22 . Preferably, a distal annular groove  81  is also provided. 
         [0029]    The locking member  33  is configured so that in its natural unlocked state ( FIG. 4B ), the interior bore  72  is sufficiently large to permit the catheter  22  to slide axially and rotate in the bore  72  and through the sleeve passageway  39 . The physician can compress the locking member wall  66  around the catheter to frictionally engage the locking member inner surface  70  against the catheter outer surface  44  to thus lock the catheter outer surface  44  to the sleeve  30  to prevent any relative movement therebetween. This locked state can be maintained by tying suture thread  82  around the locking member wall in grooves  80 ,  81 . Of course, the thread  82  can be readily cut when it is desired to release the locked state to allow the catheter to be repositioned and/or replaced.  FIGS. 4D and 4E  depict exemplary spring clips  83  which can be alternatively placed in the grooves  80 ,  81  in lieu of thread  82  for clamping the locking member in its locked state. 
         [0030]    The layer of porous material  31 , e.g., titanium mesh, as described in U.S. application Ser. No. 10/821,383, is mounted around the outer surface  37  of sleeve  30 , close to the sleeve distal end  42 . In use, it is intended that the sleeve distal end be inserted through an incision  24  in the patient&#39;s skin to position the porous layer  31  just below the patient&#39;s epidermal skin layer  84  and in contact with the patient&#39;s dermal layer  85 . Note that the porous layer  31  is preferably oriented diagonally with respect to the axis of sleeve  30  to better conform to the patient&#39;s skin contour. This orientation optimizes contact between the porous layer  31  and the patient&#39;s subcutaneous tissue to promote, over time, ingrowth into the porous layer. This tissue ingrowth acts to firmly anchor the sleeve in place and to form an infection resistant barrier around sleeve  30 . This barrier may be enhanced by incorporating antimicrobial, bioactive, and/or anti-inflammatory constituents into the porous layer  31 . For example, silver containing compounds and/or antibiotic eluting and/or growth factor coatings can be used as antimicrobial agents and steroids can be used as anti-inflammatory agents. 
         [0031]    The aforementioned protective sheath  34  is formed of thin flexible tubular material (e.g., 0.010″ wall FEP tubing) and is intended to be mounted around sleeve  30  and porous layer  31  prior to use to avoid injuring the patient&#39;s tissue when the sleeve distal end  42  is inserted through the incision  24 . As described in said U.S. application Ser. No. 11/708,445, the sheath  34  is removed from the sleeve  30  by the physician after the sleeve and porous layer have been inserted through the incision. 
         [0032]    More particularly, the sheath  34  is preferably configured as a substantially tubular, e.g., cylindrical, body  86  having a distal collar  87  and a proximal elongate pull tab  88 . An outwardly tapering section  89  extends from the collar  87  to the main body portion  86 . Note that the collar  87  and distal portion of section  89  have a diameter smaller than that of the porous layer  31 . For example only, the sleeve  30  may have an outer diameter of 0.250 inches, the porous layer  31  an outer diameter of 0.310 inches and the collar  87  an inner diameter of 0.193 inches. An axially oriented score, or perforated line  90  is preformed through the collar  87 , the tapering section  89  and the body portion  86  to facilitate the physician peeling the sheath  34  from the sleeve  30 . Note in  FIG. 4A  that the sheath fits tightly around the periphery of sleeve  30  and porous layer  31  and that the tapering section  89  is positioned distally of the porous layer  31 . In use, the physician is able to readily peel the sheath from the sleeve with one hand by rolling, or winding, the elongate tab to pull the sheath axially in a proximal direction. Peeling occurs because as the sheath is pulled proximally, the tapering section  89  and collar  87  have to move past the larger diameter porous layer  31  which action causes the sheath to tear along score line  90  allowing it to be easily stripped from the sleeve  30 . 
         [0033]    In the preferred catheter assembly illustrated in  FIGS. 2-4A , the sleeve  30  comprises a rigid titanium tube characterized as follows: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 overall length 
                 1.135 inches  
               
               
                   
                 proximal end 45 length 
                 .250 inches 
               
               
                   
                 passageway 39 ID 
                 .200 inches 
               
               
                   
                 end 45 ID 
                 .313 inches 
               
               
                   
                 sleeve 30 wall thickness 
                 .025 inches 
               
               
                   
                 porous material 31 OD 
                 .304 inches 
               
               
                   
                 nib 54 ID 
                 .170 inches 
               
               
                   
                   
               
             
          
         
       
     
         [0034]    In an alternative embodiment, the sleeve can be similarly dimensioned but instead of being formed of a rigid material such as titanium, can be formed of a flexible material such as silicone. In such an embodiment, the annular sealing nibs  54  can be integrally formed with the sleeve. 
         [0035]    As previously mentioned the apparatus of  FIGS. 1-6  enables a physician to replace an implanted catheter by unlocking the locking member  33  and sliding the implanted catheter proximally through the sleeve  30 . 
         [0036]    Attention is now directed to  FIGS. 7 and 8  which illustrate a preferred portal device  100  in accordance with the present invention. The portal device  100  is intended to be used in combination with the aforedescribed catheter assembly  20  to allow various procedural tools, e.g., balloon and angiographic catheters, access to the interior body path and to allow the selected infusion of medication for treating infections. 
         [0037]    The portal device  100  is comprised of catheter connector  102  carrying a distally projecting flexible tube  104  which defines a central lumen. The distal end  106  of the tube  104  is preferably beveled at  107  to facilitate insertion into the passageway proximal end of sleeve  30 . The tube  104  preferably carries a conventional pinch clamp  108 . The proximal end of connector  102  is preferably provided with a detachable fitting  110 , e.g., Luer, for coupling to a hemostatic valve device  120 , e.g., Touhy-Borst, of the type depicted in  FIG. 9 . 
         [0038]    A Touhy-Borst hemostatic valve device  120  is well known in the art and readily commercially available, e.g., Qosina P/N  80375 . It comprises a tube  122  defining a main lumen having an entrance port  124  and exit port  126 . The distal end of tube  122  is formed with a Luer fitting  128  for coupling to the fitting  110  on the proximal end of portal device connector  102 . An adjustable valve mechanism  126  is mounted near the proximal end of device  120  mounted between the main lumen entrance port  124  and exit port  126 . The device  120  also includes a side arm  128  defining a side lumen having an entrance port  130  and an exit port  132  which opens into the main lumen upstream from exit port  126 . 
         [0039]    In general use, an implanted catheter is first extracted from sleeve  30  and then the projecting tube  104  of portal device  100  is inserted into the proximal end of the sleeve passageway  39 . Depth markings  134  on the exterior surface of tube  104  assist the physician in properly inserting tube  104  into the sleeve passageway. With the portal device  100  properly installed to the sleeve, the hemostatic valve device  120  can then be coupled to the portal device via respective Luer fittings  110  and  128 . 
         [0040]    By way of background, it is generally known that the long term implantation of a catheter causes an internal tunnel to form around the catheter. The tunnel is composed of a fibrin sheath, or eventually, an epithelialized capsule, which isolates the tunnel interior from the surrounding subcutaneous tissue. The tunnel can be used to infuse suitable medication and/or provide interventional tool access. 
         [0041]    In a specific application of a portal device in accordance with the invention to treat infection, first assume that a catheter has been implanted using the catheter assembly  20  depicted in  FIGS. 1-6 . Further assume that the physician has reason to suspect an infection is developing along the patient&#39;s interior body path. The physician then may proceed as follows: 
         [0042]    a) Cut the suture/wire on the locking member  33 . 
         [0043]    b) Temporarily remove the locking member  33  from the catheter 
         [0044]    c) Retract the catheter through the sleeve  30 . 
         [0045]    d) Insert the portal device projecting tube into the proximal end of the sleeve passageway  39 . 
         [0046]    e) Lock the locking member  33  to hold the portal device. 
         [0047]    f) With the portal device locked by locking member  33 , inject liquid medication into the proximal end of the portal device, e.g., via the Touhy-Borst hemostatic valve assembly side arm  128 , for passage to the interior tunnel and venotomy site. 
         [0048]    g) After a suitable interval, e.g., 24-48 hours, aspirate the liquid medication from the tunnel with a syringe through the Touhy-Borst side arm  128   
         [0049]    h) Cut the suture/wire on the locking member  33  and remove the portal device. 
         [0050]    i) Thread a new catheter through the tunnel to the venotomy site; 
         [0051]    j) Lock the locking member  33  and secure with suture/wire; 
         [0052]    In a different exemplary application to perform an angiographic procedure, the physician may proceed as follows: 
         [0053]    a) Advance a guidewire through the implanted catheter 
         [0054]    b) Cut the suture/wire on the locking member  33 . 
         [0055]    c) Retract the catheter through the sleeve  30 . 
         [0056]    d) Insert the portal device projecting tube into the proximal end of the sleeve passageway  39 . 
         [0057]    (e) Thread an angiographic catheter ( FIG. 10 ) over the guide wire via the hemostatic valve assembly main entrance port  124 . 
         [0058]    (f) Inject radiopaque contrast dye via the valve side port  130  and visually observe with angiography. 
         [0059]    (g) If a need for angioplasty is indicated, retract the angiography catheter and thread the angioplasty catheter onto the guide wire. 
         [0060]    (h) Perform angioplasty to ablate the distal fibrin sheath. 
         [0061]    (i) Retract the angioplasty catheter, the hemostatic valve assembly, and the portal device and thread a new hemodialysis catheter over the wire. 
         [0062]    (j) Remove the wire. 
         [0063]      FIG. 10  depicts an assembly  150  in accordance with the invention in combination with an exemplary tool, e.g., a balloon catheter  152 , for performing an angioplasty procedure. The assembly  150  includes the aforedescribed sleeve  30  carrying porous layer  31 , the portal device  100  including flexible tube  104 , and the hemostatic valve device  120 .  FIG. 10  illustrates an exemplary balloon catheter  152  extending through the main lumen of the valve device  120 , through the portal device  100  and through the sleeve  30  projecting past the sleeve distal end  42 . The valve device side port  128  is shown closed by cap  153 . The catheter  150  distal end  154  carries an expandable balloon  155 . The proximal end  156  of catheter  152  extends proximally from the entrance port  124  of the valve device  120  and terminates in a conventional fitting  160  having dual entrance ports  162 ,  164 . A syringe  166  is used to supply fluid via port  162  to the distal end  154  of catheter  150  to expand the balloon  155 . 
         [0064]    From the foregoing, it should now be understood that a method and apparatus have been described for facilitating the management of percutaneous conduits intended for long term implantation. Embodiments of the invention permit an implanted conduit to be withdrawn from the body through a percutaneous sleeve carrying porous material configured to integrate with a patient&#39;s dermal tissue. With the conduit removed, the interior tunnel can be used to pass procedural tools, e.g., an angiographic catheter, and/or to treat infections occurring at the incision site, a venotomy site, along the tunnel therebetween, or in the bloodstream. 
         [0065]    Although, the preferred embodiment has been described with reference to a specific exemplary apparatus described in aforementioned application Ser. No. 11/708,445, it should be understood that the invention is also applicable to other structurally distinct, but functionally analogous, apparatus. Accordingly, it is recognized that various modifications and alternatives will occur to those skilled in the art consistent with the sprit of the invention and which fall within the intended scope of the appended claims.