Abstract:
A tunneling device is provided which includes a substantially rigid rod, an energy emitting part at a distal end of the rod, a catheter holding part at a proximal end of the rod, an energy source connected to the energy emitting part, and a control section for activating the energy source to transmit energy to the energy emitting part, so as to cause the energy emitting part to emit cutting and/or cauterizing energy. The substantially rigid rod is adapted to be guided through body tissue while the energy source is active so as to facilitate movement and control of the guided rod.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the priority of U.S. Provisional Applications Ser. No. 60/496,812 filed Aug. 21, 2003 and Ser. No. 60/505,081 filed Sep. 22, 2003, the entire contents of both of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to a tunneling device for creating a path for a subcutaneous catheter.  
         [0003]     The invention further relates to an apparatus for monitoring movement of a tunneling device along a subcutaneous path.  
       BACKGROUND OF THE INVENTION  
       [0004]     Several surgical/interventional procedures require tunneling through soft-tissue in order to create a path into which a catheter or graft may be inserted. One such procedure is the insertion of a ventriculo-peritoneal catheter, which allows excess fluid in the brain to be drained into the abdomen. In order to place the catheter, a subcutaneous tunnel is created through the soft tissue of the body from the head to the abdomen. Another such procedure is the insertion of a tunneled central venous catheter which enters a body just over the chest and travels subcutaneously to the internal jugular vein. Moreover, tunneling devices may be used to create paths for vascular grafting.  
         [0005]      FIG. 1  shows a schematic view of a typical tunneling device. Currently, devices for creating a tunnel for the insertion of a catheter comprise only a rigid rod  1 , a blunt distal end  4  of the rod  1  which is pushed through soft tissue, and a catheter  3  attached to a proximal end  2  of the rod  1 . The device must be pushed through soft tissue to create a pathway for the catheter. However, it is difficult to push the rod through some types of tissue, and different degrees of force are necessary for different types of tissue. Indeed, the force required to push the device can be so large that the rod may move uncontrollably once tissue gives way under the force. In addition, tunneling through soft tissue sometimes causes bleeding which cannot be halted by the tunneling devices which are currently known.  
         [0006]     Still further, when using a tunneling device, it is sometimes difficult for a surgeon to determine a location of the distal end of the rod within the body, forcing the surgeon to estimate the location of the distal end of the rod. This practice can be dangerous, especially traveling near lung and abdominal tissue, for example.  
       OBJECT OF THE INVENTION  
       [0007]     It is an object of the present invention to provide a device for tunneling through soft tissue which does not encounter the above-described problems of uncontrolled movement and bleeding.  
         [0008]     It is an additional object of the present invention to provide an apparatus which can monitor the location of the distal end of the rod by monitoring the type of tissue which surrounds the rod.  
       SUMMARY OF THE INVENTION  
       [0009]     To achieve the object of the invention, a tunneling device is provided which comprises a substantially rigid rod, an energy emitting part at a distal end of the rod, a catheter holding part at a proximal end of the rod, an energy source connected to the energy emitting part, and a control section for activating the energy source to transmit energy to the energy emitting part, so as to cause the energy emitting part to emit cutting and/or cauterizing energy, wherein the substantially rigid rod is adapted to be guided through body tissue while the energy source is active so as to facilitate movement and control of the guided rod.  
         [0010]     The energy emitting part may comprise an electrode cap which is monopolar or bipolar, and the energy source may comprise a Radio Frequency (RF) generator.  
         [0011]     Alternatively energy source may comprise a battery housed in a casing that is directly connected to the substantially rigid rod.  
         [0012]     Alternatively, the energy emitting part may comprise one of a laser tip and an ultrasonic tip and the energy source may comprise a laser power source or ultrasound generator respectively.  
         [0013]     Alternatively, the energy emitting part may comprise a mechanical cutting tool.  
         [0014]     The energy source may be connected to the energy emitting part by an insulated wire.  
         [0015]     The control section may comprise a foot pedal, trigger, or other control mechanism.  
         [0016]     The control section may further comprise a timing section for activating the energy source for a only a predetermined period of time.  
         [0017]     The tunneling device may further comprise a tube attached to the substantially rigid rod and a syringe connected to a proximal end of the tube, wherein the syringe and tube are adapted to deliver antibiotic or anesthetic medications at the distal end of the substantially rigid rod.  
         [0018]     In an alternative means of achieving the object of the invention, a tunneling device is provided which comprises a metallic rod insulated except at a distal end thereof, an energy source connected to the metallic rod, and a control section for activating the energy source to transmit energy to the energy emitting part, so as to cause the energy emitting part to emit cutting and/or cauterizing energy, wherein the metallic rod is adapted to be guided through body tissue while the energy source is active so as to facilitate movement and control of the guided rod.  
         [0019]     The energy source may comprise a Radio Frequency (RF) generator and may be connected to the metallic rod by an insulated wire.  
         [0020]     The control section may comprise a foot pedal, trigger, or other control mechanism.  
         [0021]     The control section may further comprise a timing section for activating the energy source for a only a predetermined period of time.  
         [0022]     The tunneling device may further comprise a tube attached to the insulated metallic rod and a syringe connected to a proximal end of the tube, wherein the syringe and tube are adapted to deliver antibiotic or antiseptic medications at the distal end of the metallic rod.  
         [0023]     In another alternative means of achieving the object of the invention, a tunneling device is provided which comprises a pair of metallic rods insulated on an exterior surface except at a distal end thereof and separated by insulation except at a proximal and a distal connection point, an energy source connected to the metallic rods, and a control section for activating the energy source to transmit energy to the energy emitting part, so as to cause the energy emitting part to emit cutting and/or cauterizing energy, wherein the metallic rod is adapted to be guided through body tissue while the energy source is active so as to facilitate movement and control of the guided rod.  
         [0024]     To achieve the additional object of the invention, a tissue impedance measuring apparatus is provided which comprises an impedance measuring section for measuring tissue impedance at the location of the distal end of the rod, and a display section for displaying impedance data measured by the impedance measuring section.  
         [0025]     The apparatus may further comprise an alarm generating section for generating an alarm when a predetermined impedance parameter is exceeded. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a schematic view of a conventional tunneling device.  
         [0027]      FIG. 2  is a schematic view of the present invention.  
         [0028]      FIG. 3  is a schematic view of a second embodiment of the present invention.  
         [0029]      FIG. 4  is a schematic view of a third embodiment of the present invention;  
         [0030]      FIG. 5  is a schematic view of a fourth embodiment of the present invention; and  
         [0031]      FIG. 6  is a schematic view of a fifth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0032]      FIG. 2  shows a schematic view of a first embodiment of the present invention. A substantially rigid rod  1  has an electrode cap  2  attached to a first end of the rod  1  and a catheter  8  is attached to a catheter holding part  9  of a second end of the rod  1 . A Radio Frequency (RF) generator  5  is attached to the electrode cap  2  by an insulated wire  3  which enters the rod  1  near the catheter holding part  9 , runs through a center portion of the rod  1 , and attaches to a side of the electrode cap  2  which is connected to the rod  1 . A foot pedal  4  is connected to the RF generator  5 .  
         [0033]     The device is utilized by first placing a grounding pad  7  on a patient  6 . The rod  1 , to which the catheter  8  is attached, is inserted into an entry point incision and the RF generator  5  is activated by depressing the foot pedal  4 . Energy is sent from the RF generator  5  to the electrode cap  2  via the insulated wire  3 , causing the electrode cap  2  to emit heat which cuts through soft tissue. As the device cuts the tissue, the heat emitted by the electrode cap  2  also cauterizes the wounds, thereby preventing bleeding.  
         [0034]     After the tunnel for the catheter has been created, the rod  1  is removed from the body via an exit point incision. The insulated wire  3  is cut near to the rod  1  and removed from the tunnel through the entry point incision of the rod  1 . Alternatively, the insulated wire  3  may be detached from the RF generator  5  and removed through the exit point incision.  
         [0035]     An additional safety may be utilized by attaching the foot pedal  4  to a timer  11  which limits the time that the RF generator is allowed to run without releasing and re-depressing the foot pedal.  
         [0036]     Because the conductivities of different types of tissue vary, different types of tissue may be distinguished by respective impedance values. An impedance monitor  12  may be attached to or built into the RF generator  5  for measuring the impedance of the tissue encountered by the electrode cap  2 . A display screen  10  can then display the impedance values measured by the impedance monitor. (See “Measurement of Needle-Tip Bioimpedance of Facilitate Percutaneous Access of the Urinary and Biliary Systems”, the entire contents of which are incorporated herein by reference.)  
         [0037]     In addition, an alarm  13  may be set to generate an alarm such as a flashing light, loud noise, or other warning, in response to impedance value changes exceeding a preset limit.  
         [0038]      FIG. 3  shows a schematic view of the second embodiment of the present invention. The substantially rigid rod  1 , catheter  8  and catheter holding part  9  are the same as those shown in  FIG. 2 . A rechargeable battery  18  is held in a casing  16 , which is attachable to the substantially rigid rod  1 . When the casing  16  is attached to the substantially rigid rod  1 , two electrodes  15   a  and  15   b  on an outside surface of the casing connect to two electrodes  14   a  and  14   b  on an outside surface of the substantially rigid rod  1 . Two wires  19   a  and  19   b  connect to the electrodes  14   a  and  14   b  and to a bipolar electrode cap  27 . Because the electrode cap  27  is bipolar, no grounding pad  7  is required.  
         [0039]     The device is activated by depressing a trigger  17  connected to the outside surface of the casing  16 . When the trigger  17  is depressed, energy is transmitted from the battery  18  through the electrodes  15   a  and  15   b ,  14   a  and  14   b  and through the wires  19   a  and  19   b  to the electrode cap  2 . The electrode cap  2  then emits heat which cuts through soft tissue and cauterizes the wounds, thereby preventing bleeding.  
         [0040]     After the tunnel for the catheter has been created, the casing  16  is detached from the rod  1 , which is removed from the body via an exit point incision.  
         [0041]      FIG. 4  shows a third embodiment of the present invention. References  5 - 8  identify features that are the same as those described above with respect to  FIG. 1 . The generator  5  is connected to a metallic rod  21  by an insulated wire  20 . The metallic rod is connected to the catheter  8  by a catheter holding part  22  and is insulated except at a distal end  24  by insulation  23 .  
         [0042]     When the generator  5  is activated, energy is transmitted through the insulated wire  20  to the metallic rod  21 . The energy is then emitted in the form of heat from the distal end  24  of the metallic rod  21 . The heat cuts through soft tissue and cauterizes the wounds, thereby preventing bleeding.  
         [0043]     After the tunnel for the catheter has been created, the metallic rod  21  is removed from the body via an exit point incision. The insulated wire  20  is cut near to the rod  1  and removed from the tunnel through the entry point incision of the rod  1 . Alternatively, the insulated wire  20  may be detached from the RF generator  5  and removed through the exit point incision.  
         [0044]      FIG. 5  shows a fifth embodiment of the present invention. References  1 - 9  identify features that are the same as those described above with respect to  FIG. 1 . A tube  25  is attached to the substantially rigid rod  1  and is connected to a syringe  26 .  
         [0045]     When the device is activated as described hereinabove, the syringe  26  is depressed to administer antibiotic or anesthetic medications through the tube  25 .  
         [0046]      FIG. 6  shows a fifth embodiment of the present invention. References  15 - 18  designate the electrodes, casing, trigger and battery of  FIG. 3 . A pair of metallic rods  27   a  and  27   b  are connected at distal and proximal ends thereof and insulated by insulation  29  between points of connection and are insulated on an exterior surface except at the distal end by insulation  23 . A catheter holding part  22  connects the metallic rods to a catheter  8 , and electrodes  30   a  and  30   b  connect to electrodes  15   a  and  15   b . The device is operated in the same manner as the device of the third embodiment. When activated, energy is emitted from the distal end of the device where the metallic rods connect.  
         [0047]     Additional advantages and modifications will readily occur to those skilled in the art. The electrode cap  2  may be replaced by an ultrasonic tip, a laser tip, or a mechanical cutting tool and the RF generator may be replaced by another power source such as a laser generator or ultrasound generator.  
         [0048]     The impedance monitor  12 , timer  11 , alarm  13  and display screen  10  may comprise a device separate from the energy source. In addition, the devices of the third and fifth embodiments may be connected to another power source by a wire.  
         [0049]     Moreover, the catheter or graft is not necessarily attached to the catheter holding part. The device may be attached to a string that is pulled through the created tunnel and which is utilized to pull the catheter through the tunnel, or the catheter or graft may be independently guided through the tunnel.  
         [0050]     Still further, the syringe  26  and tube  25  may be used in combination with the devices of the second and third embodiments. And each of the first through third and fifth embodiments may be either monopolar or bipolar.  
         [0051]     Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.