Abstract:
A cable assembly interconnects an electrosurgical instrument and source equipment for power and fluid transfer. The cable assembly includes a unitary tubular assembly forming a lumen(s) and an insulating sheath(s) for an electrically conducting cord that are integrally interconnected via a web arrangement in a continuum of material. The web arrangement has a thickness sufficient to allow the lumen(s) and sheath(s) to be pulled apart upon application of a pulling force in a direction transverse to the direction of elongation of the tubular assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
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   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   BACKGROUND OF THE INVENTION 
   A variety of electrosurgical devices are available for performing different surgical procedures. For example, coagulation procedures require an instrument that is capable of coagulating tissue to stop or minimize the flow of blood at the surgical site. Such instruments may also be capable of flushing an irrigation solution into the area where the surgeon is working to remove bits of tissue or blood. In other alternatives, these instruments may be capable of aspirating fluids from the site. Such fluids include liquids, such as saline solution or blood, and gases, such as smoke or air. 
   For example, electrosurgical forceps have a pair of blades that are used to grasp and coagulate tissue. The forceps may be monopolar or bipolar. In monopolar forceps, one or both of the blades form an electrode in electrical communication with an electrical generator. Current flows from the active electrode through the patient&#39;s tissue to a dispersive electrode in contact with the patient&#39;s skin, which may be at some distance from the forceps, and back to the generator. In bipolar forceps, each blade of the pair comprises an electrode in communication with the electrical generator. 
   In some forceps, an irrigation channel is formed along one or both of the blades to allow an irrigation fluid, such as saline solution, to flow through the channel and out the outlet near the tip of the blades to flush bits of tissue or blood away from the area where the surgeon is working. See, for example, U.S. Pat. No. 6,228,084. 
   In another known type of bipolar coagulating instrument, a pair of electrodes is arranged coaxially. A suction channel is provided along the central axis to draw fluids away from the surgical site. See, for example, U.S. Pat. Nos. 5,989,249 and 6,406,476. 
   In instruments that provide both coagulation capabilities and irrigation or aspiration capabilities, the instrument must be connected to both an electrical generator via an electrically conducting cord and to a fluid pump or vacuum compressor for irrigation or aspiration via a lumen. The electrically conducting cord is formed with a pair of copper wires each coaxially surrounded by an outer insulation. The fluid tubing for the lumen is typically formed from a suitable plastic material. It is known to form an electrically conducting cord and a lumen into a cable assembly by bonding the cord and lumen together with a glue or other bonding solution. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a dual-function cable assembly in which an electrically conducting cord is integrally formed with an additional lumen or lumens. The cable assembly carries electrical energy from a source to an electrosurgical instrument. In addition, the cable assembly has the ability to irrigate or aspirate from the instrument end via a fluid or vacuum source through the lumen or lumens integrally connected to the electrical cord. 
   The electrical cord and the lumen(s) are arranged in a compact configuration and are interconnected by an integrally formed web arrangement that is sufficiently strong to hold the cord and lumen(s) together but is sufficiently thin to allow the lumen to be “unzipped” from the cord for a distance to facilitate connections at the source end or the instrument end. 

   
     DESCRIPTION OF THE DRAWINGS 
     The invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is an isometric view of a cable assembly according to the present invention; 
       FIG. 2  is a partial cross-sectional view of the cable assembly of  FIG. 1 ; 
       FIG. 3  is a partial cross-sectional view of a further embodiment of the cable assembly of the present invention; 
       FIG. 4  is a partial cross-sectional view of a still further embodiment of the cable assembly of the present invention; and 
       FIG. 5  is a partial cross-sectional view of a still further embodiment of the cable assembly of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A first embodiment of a cable assembly according to the present invention is illustrated in  FIGS. 1 and 2 . The cable assembly  10  includes one or more electrically conducting cords  12 ,  14 , each having a copper or other electrically conducting wire  16 ,  18  enclosed within an insulating sheath  20 ,  22 . One or more lumens  24  are provided in the form of tubing  28  defining a fluid passage  26  therethrough. The electrically conducting cords and the lumen(s) extend longitudinally from a source end  30  to an instrument end  32 . The cords and lumen(s) are attachable via suitable fittings at the source end to suitable source equipment (not shown), such as an electrical generator for the electrical cords and a fluid or vacuum source, e.g., a fluid pump or vacuum compressor, for the lumen(s). Similarly, the cords and lumen(s) are attachable via suitable fittings at the instrument end to an electrosurgical instrument. The lumen, or lumens, allows, for instance, irrigation using saline to the electrosurgical site through the instrument connected at the instrument end of the cable assembly. The lumen may also be used for aspiration from a site of either a liquid (for example, saline or blood) or a gas (for example, air or smoke). 
   The fittings  34  at the source end of the electrical conducting cords include any appropriate termination that connects to the electrical generator, such as banana pin connectors, phone jack connectors, and the like. The fittings  36  at the instrument end include any appropriate termination that connects to the instrument; typically, standard diameter pins, such as 0.073 inches, are provided. Similarly, the ends of the lumen(s) can be terminated in various ways to make the connections to the appropriate instrument and source. Typically, luer taper fittings  38  are provided for connection to medical devices. 
   The two insulating sheaths  20 ,  22  and the tubing  28  of the lumen  24  are formed of a flexible plastic material. The two insulating sheaths and the tubing of the lumen are integrally connected to each other via a web arrangement  40  in a continuum of material to form a single, unitary tubular assembly. In the embodiment illustrated in  FIG. 2 , the web arrangement comprises a cross web  42  connecting the two electrically insulating sheaths to each other and an orthogonal web  44  connecting the lumen to the cross web. Preferably, the orthogonal web connecting the lumen to the electrical cords can be torn or be “unzipped” in a direction extending along the length of the cable assembly when the lumen is pulled away from the electrical cords by a force transverse to the direction of elongation. Similarly, the cross web can be torn to separate the two electrical cords. The webs can be made sufficiently thin to provide this tearable capability. If the webs were too thick, they would not tear properly or easily and would leave a ragged edge. Unzipping the lumen from the electrical cords at the source end can facilitate connection of the source ends of the lumen and the electrical cords to the source equipment, such as the electrical generator and the fluid pump or compressor. Similarly, unzipping the lumen from the electrical cords at the instrument end can facilitate connection of the instrument ends of the lumen and the electrical cords to the instrument. 
   The insulating sheath  20 ,  22 , the lumen tubing  28 , and the web arrangement  40  form a unitary tubular assembly comprising a continuum of flexible, plastic material. Suitable materials include polyvinyl chloride (PVC) or another flexible insulating plastic. The material should not be hard (not have a high durometer) and it should not be hydroscopic such that it holds so much water as to become slippery. The lumen tubing should be made of biocompatible material. The material cannot be water soluble or soluble in any fluid used for irrigation. 
   In a suitable exemplary embodiment, the web thickness is between 0.011 inch and 0.020 inch. The insulating sheath thickness is approximately 0.025 inch. The lumen tubing wall thickness is approximately 0.020 inch. It will be appreciated that these dimensions are merely exemplary of a suitable embodiment. 
   The cable assembly  10  is formed by a single extrusion process that ensures that the insulating sheaths  20 ,  22 , the lumen tubing  28 , and the web arrangement  40  are all formed as a single, unitary, integral assembly, with the sheaths surrounding the wires  16 ,  18 . In a suitable extrusion process, plastic pellets, typically at room temperature, are placed into an extruder and heated above the melting temperature of the plastic. The extruder also pressurizes the plastic when in the molten stage. Once molten and at a high pressure, the plastic melt is forced through a die that has been cut to provide the desired profile of the cable assembly. The wires are also introduced into the die, as is known in the art. Once the melt has been forced through the die, it is cooled, preferably in a bath, to harden the plastic into the required shape and profile. 
   In another embodiment, the cable assembly can be formed from two materials co-extruded together. For example, one material can be used for the insulating sheaths of the electrical cord and another material can be used for the lumen tubing. The two materials are melted and fed through separate but closely arranged dies. Immediately upon exiting the dies, the materials are still in a molten state and are brought into contact. The two materials contact and melt together at the cross web or webs, thus resulting in a single, unitary, integral assembly. The assembly is then introduced into the cooling bath. Different materials can, in this manner, be selected to optimize the properties for the insulating sheaths and for the lumen tubing. Also in this manner, the lumen tubing can be provided in a different color from the electrical cord to allow a user to more readily distinguish the lumen visually from the electrical cord. 
   The electrical cords and the lumen(s) are preferably arranged in the most compact geometrical cross-section possible for the desired number of cords and lumens. In the embodiment illustrated in  FIG. 2 , two electrical cords  12 ,  14  and one lumen  24  are arranged in a triangular or pyramidal cross-sectional configuration. This configuration provides a compact arrangement that takes up a minimum amount of cross-sectional space and provides the feel of a single cable to the user. This cable assembly is suitable for use with a bipolar electrosurgical instrument requiring two electrical conductors and having one irrigation or aspiration line. 
     FIG. 3  illustrates a further embodiment having an alternative interconnecting web arrangement  140 . The insulating sheaths  120 ,  122  of two electrical cords  112 ,  114  are connected to each other with a cross web  142 . A single lumen  124  is connected to each of the insulating sheaths by two further cross webs  144 ,  146 . The three cross webs form a generally triangular arrangement. This arrangement is advantageous in that, if one web were severed unintentionally, the other two webs would still be available to hold the sheaths and tubing together. 
   Other arrangements are possible. For example, the instrument connected to the end of the cable can be monopolar, in which case the cable requires only a single electrical conductor.  FIG. 4  illustrates a suitable embodiment with one electrical cord  212  and one lumen  224  arranged in a linear or ribbon configuration. In another embodiment, the cable assembly can include further conductors for other potential uses, such as three conductors for use in connecting to a hand-switching device that can be either monopolar or bipolar, depending on the state of the switch. 
   In another embodiment, the cable assembly includes two electrical conducting wires  312 ,  314  and two irrigation lumens  324 ,  325 . See  FIG. 5 . The two electrical cords and two lumens are arranged in a rectangular cross-sectional configuration. In this embodiment, the irrigation lumens are isolated from each other to allow the infusion of two separate fluids or to allow for connection to an instrument that has two irrigating or aspirating lines, such as dual irrigating forceps. Two isolated irrigation lines are required for dual irrigating forceps to eliminate the potential of the electrical connection being made through the saline instead of between the bipolar forceps tines through the tissue. 
   The invention is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.