Abstract:
A method of producing an electrosurgical device is disclosed. Opposing longitudinal clamshells are formed, and each clamshell includes a face having a generally planar major portion. Longitudinal grooves are formed in a clamshell, and an electrical conductor in a disposed in a groove. The faces are aligned to form an electrical passage including the electrical conductor in the groove and a spaced-apart fluid passage with another groove. The clamshells are welded together to form a shaft member such that the electrical passage and the fluid passage are fluid tight along a major longitudinal portion of the shaft. Electrodes are attached to the distal end of the shaft and are in electrical communication with the electrical conductor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/790,309, filed May 28, 2010, now abandoned, and entitled “Fluid-Assisted Electrosurgical Devices, and Methods of Manufacture Thereof”, the entire teachings of which are incorporated herein by reference. 
    
    
     FIELD 
     This invention relates generally to the field of medical systems, devices and methods for use upon a body during surgery. More particularly, the invention relates to electrosurgical systems, devices and methods for use upon tissues of a human body during surgery, particularly open surgery and minimally invasive surgery such as laparoscopic surgery. 
     BACKGROUND 
     Dry-tip electrosurgical devices (e.g. monopolar pencil) have been known to cause tissue desiccation, tissue sticking to the electrodes, tissue perforation, char formation and smoke generation. More recently, fluid-assisted electrosurgical devices have been developed which use saline to inhibit such undesirable effects, as well as cool the tissue being treated and electrically couple the device to the tissue. The present invention provides a further improvement to fluid-assisted electrosurgical devices by providing an improved construction which better promotes the manufacture thereof. 
     SUMMARY 
     This invention provides a fluid-assisted electrosurgical device to treat tissue in a presence of radio frequency energy and a fluid provided from the device. In one embodiment, the device comprises a handle, a rigid shaft member distal to the handle, and at least one electrode distal to the shaft member. The shaft member comprises a shaft member first body and a shaft member second body joined together along a length of the shaft member. The shaft member further comprises a plurality of longitudinally oriented shaft member passages. The passages may be parallel and positioned along side one another, and have a length defined by the shaft member first body and the shaft member second body. The shaft member first body and the shaft member second body may be made of a plastic material. 
     In certain embodiments, the plurality of shaft member passages includes an electrical passage containing an electrical conductor, with the electrical conductor electrically coupled to the electrode. The electrical conductor may extend from a proximal end of the shaft member to a distal end of the shaft member where it may be in direct contact with the electrode. The electrical conductor and the electrode may contact one another within a receptacle for the electrode at a distal end of the shaft member. The electrical conductor may be made of sheet metal. 
     In certain embodiments, the electrical conductor and at least one of the shaft member first body and the shaft member second body may have interconnecting mating features to position the electrical conductor relative to at least one of the shaft member first body and a shaft member second body. The interconnecting mating features may comprise a keyway and a key configured to interconnect with the keyway. In one embodiment, the electrical conductor interconnecting mating feature may comprise the keyway, and the interconnecting mating feature of at least one of the shaft member first body and the shaft member second body may comprise the key configured to interconnect with the keyway. In an alternative embodiment, the keyway may be provided with at least one of the shaft member first body and shaft member second body and the key may be provided with the electrical conductor. 
     In other embodiments, the plurality of shaft member passages may include a fluid delivery passage, and the fluid delivery passage may be in fluid communication with a fluid outlet configured to provide fluid to the electrode. The fluid outlet may be at least partially defined by the electrode. The shaft member fluid delivery passage may pass through a shaft member connector portion configured to connect the shaft member fluid delivery passage with fluid delivery tubing within the handle. The shaft member connector portion may be defined by at least one of the shaft member first body and the shaft member second body, and may more particularly comprise a barbed connector portion. 
     In still other embodiments, the device may comprise a first electrode and a second electrode, and the plurality of shaft member passages may include a first electrical passage and a second electrical passage which are isolated from one another. The first electrical passage may contain a first electrical conductor which is electrically coupled to the first electrode, and the second electrical passage may contain a second electrical conductor which is electrically coupled to the second electrode. 
     In other embodiments, a first fluid outlet may provide fluid to the first electrode and second fluid outlet may provide fluid to the second electrode. The shaft member fluid delivery passage may include a first branch and a second branch. The shaft member fluid delivery passage first branch may be in fluid communication with the first fluid outlet configured to provide fluid to the first electrode, and the shaft member fluid delivery passage second branch may be in fluid communication with the second fluid outlet configured to provide fluid to the second electrode. The first fluid outlet may be at least partially defined by the first electrode, and the second fluid outlet may be at least partially defined by the second electrode. 
     In other embodiments, the first electrode may include a first electrode fluid delivery passage in fluid communication with the shaft member fluid delivery passage first branch, and the second electrode may include a second electrode fluid delivery passage in fluid communication with the shaft member fluid delivery passage second branch. 
     In other embodiments, the first electrode fluid delivery passage may pass through a first electrode connector portion configured to connect the first electrode to the shaft member, and the second electrode fluid delivery passage may pass through a second electrode connector portion configured to connect the second electrode to the shaft member. The first electrode connector portion may comprise a barbed connector portion, and the second electrode connector portion may also comprise a barbed connector portion. 
     In other embodiments, the shaft member first body and the shaft member second body may be welded together. The plurality of longitudinally oriented shaft member passages may be separated from one another along a common weld line or seam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of one embodiment of a system of the present invention having an electrosurgical unit in combination with a fluid source and handheld electrosurgical device; 
         FIG. 2  is a graph of the RF power output versus impedance for the electrosurgical unit of  FIG. 1 ; 
         FIG. 3  is graph showing a relationship of fluid flow rate Q in units of cubic centimeters per minute (cc/min) on the Y-axis, and the RF power setting P S  in units of watts on the X-axis; 
         FIG. 4  is a perspective view of an electrosurgical device according to the present invention; 
         FIG. 5  is an exploded perspective view of the device of  FIG. 4 ; 
         FIG. 6  is a close-up front perspective view of the shaft member of the device of  FIG. 4 ; 
         FIG. 7  is a close-up rear perspective view of the shaft member of the device of  FIG. 4 ; 
         FIG. 8  is an exploded perspective view of the shaft member of  FIGS. 6 and 7 ; 
         FIG. 9  is a close-up cross-sectional view of the shaft member of  FIGS. 6 and 7  taken along line  9 - 9  of  FIG. 6 ; 
         FIG. 10  is a close-up cross-sectional view of the shaft member of  FIGS. 6 and 7  taken along line  10 - 10  of  FIG. 6 ; 
         FIG. 11  is a cross-sectional view of the shaft member of  FIGS. 6 and 7  taken along a length of conductor  70 ; and 
         FIG. 12  is a close-up cross-sectional view of a tip portion of the device of  FIG. 4  with an exemplary fluid coupling to a tissue surface of tissue; 
     
    
    
     DETAILED DESCRIPTION 
     Throughout the description, like reference numerals and letters indicate corresponding structure throughout the several views. Also, any particular feature(s) of a particular exemplary embodiment may be equally applied to any other exemplary embodiment(s) of this specification as suitable. In other words, features between the various exemplary embodiments described herein are interchangeable as suitable, and not exclusive. From the specification, it should be clear that any use of the terms “distal” and “proximal” are made in reference from the user of the device, and not the patient. 
     The invention provides systems, devices and methods for treating tissue at a tissue treatment site during an electrosurgical procedure. This is particularly useful for procedures where it is desirable to shrink, coagulate and seal tissue against blood loss, for example, by shrinking lumens of blood vessels (e.g., arteries, veins). 
     The invention will now be discussed with reference to the figures, with  FIG. 1  showing a front view of one embodiment of a system  2  of the present invention having an electrosurgical unit  10  in combination with a fluid source  20  and a handheld electrosurgical device  30 .  FIG. 1  further shows a movable cart  12  having a support member  14  which carries a platform  16  comprising a pedestal table to provide a flat, stable surface for location of the electrosurgical unit  10 . As shown cart  12  further comprises a fluid source carrying pole  18  with a cross support for carrying fluid source  20 . 
     As shown in  FIG. 1 , fluid source  20  comprises a bag of fluid from which a fluid  22  flows through a drip chamber  24  after the bag is penetrated with a spike located at the end of the drip chamber  24 . Thereafter, fluid  22  flows through a fluid passage provided by a lumen of flexible, plastic fluid delivery tubing  26  to handheld electrosurgical device  30 . 
     As shown in  FIG. 1 , the fluid delivery tubing  26  passes through pump  28 . Pump  28  comprises a peristaltic pump and, more specifically, a rotary peristaltic pump. With a rotary peristaltic pump, a portion of the fluid delivery tubing  26  is loaded into the pump  28  by raising and lowering a pump head in a known manner. Fluid  22  is then conveyed within the fluid delivery tubing  26  by waves of contraction placed externally on the tubing  26  which are produced mechanically, typically by rotating pinch rollers which rotate on a drive shaft and intermittently compress the fluid delivery tubing  26  against an anvil support. Alternatively, pump  28  may comprise a linear peristaltic pump. With a linear peristaltic pump, fluid  22  is conveyed within the fluid delivery tubing  26  by waves of contraction placed externally on the tubing  26  which are produced mechanically, typically by a series of compression fingers or pads which sequentially squeeze the tubing  26  against a support. Peristaltic pumps are generally preferred, as the electro-mechanical force mechanism, here rollers driven by electric motor, does not make contact with the fluid  22 , thus reducing the likelihood of inadvertent contamination. 
     In one embodiment, the fluid  22  is liquid saline solution, and even more particularly, normal (physiologic) saline solution. However, although the description herein may make reference to saline as the fluid  22 , other electrically conductive fluids may be used in accordance with the invention. 
     In addition to the use of an electrically conductive fluid, as will become more apparent with further reading of this specification, fluid  22  may also be an electrically non-conductive fluid. The use of a non-conductive fluid may not offer as many advantages as a conductive fluid, however, the use of a non-conductive fluid still provides certain advantages over the use of a dry electrode including, for example, reduced occurrence of tissue sticking to the electrode(s) of device  30  and cooling of the electrode(s) and/or tissue. Therefore, it is also within the scope of the invention to include the use of a non-conductive fluid, such as, for example, deionized water. 
     As shown in  FIG. 1 , electrosurgical device  30  is connected to electrosurgical unit  10  via a cable  34  which has a plurality of electrically insulated wire conductors  42  (shown in  FIG. 5 ) and at least one plug  36  at the end thereof. The electrosurgical unit  10  provides radio-frequency (RF) energy via cable  34  to electrosurgical device  30 . Plug receptacle  38  of electrosurgical unit  10  receives the plug  36  of device  30  therein to electrically connect device  30  to the electrosurgical unit  10 . The fluid delivery tubing  26  may be provided as part of cable  34  and produced with the electrically insulated wire conductors  42  via plastic co-extrusion. 
     An exemplary RF power output curve for electrosurgical unit  10  is shown in  FIG. 2 . Impedance Z, shown in units of ohms on the X-axis and RF output power P O  is shown in units of watts on the Y-axis. In the illustrated embodiment, the RF power is bipolar and set to 200 watts. As shown in the figure, for an RF power setting P S  of 200 watts, the output power P O  will remain constant with the set RF power P S  as long as the impedance Z stays between the low impedance cut-off of 30 ohms and the high impedance cut-off of 250 ohms. Below an impedance Z of 30 ohms, the output power P O  will decrease as shown by the low impedance ramp. Above an impedance Z of 250 ohms, the output power P O  will also decrease as shown by the high impedance ramp. 
     Electrosurgical unit  10  has also been configured such that the speed of pump  28 , and therefore the throughput of fluid  22  expelled by the pump  28 , is predetermined based on two input variables, the RF power setting and the fluid flow rate setting. In  FIG. 3 , there is shown a relationship of fluid flow rate Q in units of cubic centimeters per minute (cc/min) on the Y-axis, and the RF power setting P S  in units of watts on the X-axis. The relationship has been engineered to inhibit undesirable effects such as tissue desiccation, electrode sticking, smoke production and char formation, while at the same time not providing a fluid flow rate Q at a corresponding RF power setting PS which is so great as to provide too much fluid  22  from device  30 , which may result in too much electrical dispersion and excess cooling at the electrode/tissue interface. 
     As shown, electrosurgical unit  10  has been configured to increase the fluid flow rate Q linearly with an increasing RF power setting P S  for each of three fluid flow rate settings of low, medium and high corresponding to Q L , Q M  and Q H , respectively. Conversely, electrosurgical unit  10  has been configured to decrease the fluid flow rate Q linearly with an decrease RF power setting P S  for each of three fluid flow rate settings of low, medium and high corresponding to Q L , Q M  and Q H , respectively. 
     Electrosurgical unit  10  may be particularly configured for use with an electrosurgical device  30  which is a bipolar device. With a bipolar device, an alternating current (AC) electrical circuit is created between first and second electrical poles/electrodes of the device  30 . An exemplary bipolar electrosurgical device of the present invention which may be used in conjunction with electrosurgical unit  10  of the present invention is shown at reference character  30   a  in  FIG. 4 . While electrosurgical device  30   a  of the present invention is described herein with reference to use with electrosurgical unit  10 , it should be understood that the description of the combination is for purposes of illustrating the system of the invention. Consequently, it should be understood that while electrosurgical device  30   a  disclosed herein may be used with electrosurgical unit  10 , it may be plausible to use other electrosurgical devices with electrosurgical unit, or it may be plausible to use the electrosurgical device(s) disclosed herein with another electrosurgical unit. 
     As shown in  FIG. 4 , exemplary bipolar device  30   a  comprises a proximal handle  40  comprising mating handle portions  40   a ,  40   b . Handle  40  is preferably made of a sterilizable, rigid, non-conductive material, such as a plastic material (e.g., thermoplastic such as acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC)). Also, handle  40  is preferably configured slender, along with the rest of device  30   a , to facilitate a user of device  30   a  to hold and manipulate device  30   a  like a pen-type device. Device  30   a  also includes a cable  34  which is connectable to electrosurgical unit  10  and flexible fluid delivery tubing  26  which is connectable to fluid source  20 , particularly via a spike located at the end of drip chamber  24 , which respectively provide RF energy and fluid  22  to the electrodes  100 ,  102 . 
     As shown in  FIG. 5 , cable  34  of device  30   a  comprises a plurality of insulated wires  42  connectable to electrosurgical unit  10  via three banana (male) plug connectors  44 . The banana plug connectors  44  are each assembled with wire conductors of insulated wires  42  within plug  36  in a known manner. Wire conductors of insulated wires  42  are connected distally to a handswitch assembly  46 , and thereafter wire conductors are connected to crimp terminals  48  which connect to a proximal portion of conductors  70 ,  72  of shaft member  50 . 
     Handswitch assembly  46  comprises a push button  52  which overlies a domed switch. Upon depression of button  52 , the domed switch forms a closed circuit which is sensed by electrosurgical unit  10 , which then provides RF power to the electrodes  100 ,  102 . 
     Referring to  FIGS. 6 and 7 , rigid shaft member  50 , located distal to handle  40 , comprises a shaft member first body  60  and a shaft member second body  62 . Shaft member  50  extends distally from the handle  40  and supports electrodes  100 ,  102  in rigid relation to the handle  40 . 
     At a proximal end  56  of shaft member  50 , fluid delivery tubing  26  of device  30   a  is connected within handle  40  to a proximal barbed connector portion  54  of shaft member  50 , which is defined by at least one of shaft member first body  60  and shaft member second body  62 . To connect fluid delivery tubing  26  to barbed connector portion  54 , the lumen of fluid delivery tubing  26  preferably interference (friction or press) fit over the outside diameter of barbed connector portion  54  to provide an interference fit and seal therebetween. 
     As shown in  FIGS. 8-10 , shaft member first body  60  and shaft member second body  62  comprise two opposing, mating halves of shaft member  50  which may form a clamshell design. Shaft member first body  60  and shaft member second body  62  are joined together along a length of the shaft member  50 , from a proximal end  56  to a distal end  58  thereof. Shaft member first body  60  and shaft member second body  62  may particularly be made of a rigid plastic material such as thermoplastic acrylonitrile-butadiene-styrene (ABS) or polycarbonate (PC). As used herein, a rigid plastic may be understood to be a plastic having a modulus of elasticity either in flexure or in tension greater than 700 MPA (100 kpsi) at 23° C. and 50% relative humidity when tested in accordance with ASTM methods D- 747 , D- 790 , D- 638 , or D- 882 . However, this definition is not necessarily exhaustive, but merely inclusive. Shaft member first body  60  and shaft member second body  62  may be joined by thermoplastic welding, and more particularly ultrasonic welding. In this manner, a hermetic seal may be provided between shaft member first body  60  and shaft member second body  62 . 
     Shaft member  50  includes a plurality of longitudinally oriented, tubular (enclosed), shaft member passages  64 ,  66 ,  82  and  84 , with each having a length defined by the shaft member first body  60  and the shaft member second body  62 . The passages  64 ,  66 ,  82  and  84  may be parallel and positioned to a side of one another. As shown, adjacent shaft member passages may be separated from one another by a common weld line or seam  65  which may hermetically seal the passages  64  and  66  from  82  and  84 . 
     Outer (lateral) passages  64 ,  66  of shaft member  50  more particularly comprise electrical passages which are parallel and isolated from one another, and which contain planar electrical conductors  70 ,  72 . Electrical conductors  70 ,  72  extend along the complete length of passages  64 ,  66 , and extend from entrance apertures  74 ,  76 , respectively, of passages  64 ,  66  at a proximal end  56  of shaft member  50 , as well as extend from exit apertures  78 ,  80  of passages  64 ,  66  at a distal end  58  of shaft member  50 . In a particular embodiment, electrical conductors  70 ,  72  are made of metal, and may more particularly be made of sheet metal. In this manner, conductors are rigid and may contribute to the overall stiffness of shaft member  50 . 
     Also at a proximal end  56  of shaft member  50 , electrical conductors  70 ,  72  are electrically coupled to wire conductors  42  within handle  40  whereby they may receive RF energy conducted through wire conductors  42  from electrosurgical unit  10 . At the distal end  58  of shaft member  50 , electrical conductors are electrically coupled (via direct physical contact) to electrodes  100 ,  102 , whereby they may conduct the RF energy from electrosurgical unit  10  to electrodes  100 ,  102 . As shown, electrodes  100 ,  102  are seated in distal end electrode receptacles  88 ,  90  and electrical conductors  70 ,  72  extend through apertures  78 ,  80  within the receptacles  88 ,  90  at the base thereof for the electrical conductors  70 ,  72  to make contact with electrodes  100 ,  102 . 
     By design, electrical conductors  70 ,  72  are orientation sensitive and configured to inhibit improper installation within shaft member  50 . Furthermore, electrical conductors  70 ,  72  and at least one of the shaft member first body  60  and the shaft member second body  62  have interconnecting mating features to position each electrical conductor  70 ,  72  relative to at least one of the shaft member first body  60  and the shaft member second body  62 . As shown in  FIG. 11 , the interconnecting mating feature of each electrical conductor  70 ,  72  comprises a keyway  78 ′ and the interconnecting mating feature of at least one of the shaft member first body  60  and shaft member second body  62  comprises a key  80 ′ (shown with shaft member first body  60 ) configured to interconnect with the keyway. In an alternative embodiment, the keyway may be provided with at least one of the shaft member first body  60  and shaft member second body  62  and the key  80  may be provided with the electrical conductor  70 ,  72 . 
     Returning to  FIGS. 8-10 , inner (medial) passages  82 ,  84  of shaft member  50  more particularly comprise fluid delivery passages. At the proximal end  56  of shaft member  50 , passages  82 ,  84  may branch from a common proximal fluid delivery passage  86  which passes through shaft member barbed connector portion  54  and which is in fluid communication/connected with the lumen of fluid delivery tubing  26 . 
     At the distal end  58  of shaft member  50 , passages  82 ,  84  may be in fluid communication with fluid delivery passages  104 ,  106  which pass through electrodes  100 ,  102  and terminate in exit apertures  108 ,  110 . As shown, apertures  108 ,  110  are at least partially defined by electrodes  100 ,  102 , respectively, and more particularly, are completely defined by electrodes  100 ,  102 , respectively. In the foregoing manner, exit apertures  108 ,  110  provide fluid outlets or exits configured to provide fluid  22  therefrom directly onto electrodes  100 ,  102 . Furthermore, as shown, exit apertures  108 ,  110  are proximal to a distal end of electrodes  100 ,  102 , as well as located on lateral portions of electrodes  100 ,  102 . 
     Thus, during use of device  30   a , fluid  22  from fluid source  20  is communicated through a tubular passage provided by lumen of fluid delivery tubing  26 , after which it flows through tubular fluid delivery passage  86  and tubular fluid delivery passages  82 ,  84  of shaft member  50 , and then to tubular fluid delivery passages  104 ,  106  of electrodes  100 ,  102 . After flowing through tubular fluid delivery passages  104 ,  106  of electrodes  100 ,  102 , fluid  22  may be expelled from fluid outlets  108 ,  110  onto electrodes  100 ,  102 . 
     As shown in  FIG. 10 , a female proximal connector portion  92 ,  94  of each electrode receptacle  88 ,  90  may be configured to form an interference (friction or press) fit with a male proximal connector portion  112 ,  114  of each electrode  100 ,  102 . More particularly, the female connector portion  92 ,  94  of each electrode receptacle  88 ,  90  may comprise a cylindrical recess and the male connector portion  112 ,  114  of each electrode  100 ,  102  may comprise a barbed connector portion  120 ,  122  configured to fit within the cylindrical recess. In order to increase the efficiency of the design, the first electrode fluid delivery passage  104  may pass through the first electrode connector portion  112  configured to connect the first electrode  100  to the shaft member  50 , and the second electrode fluid delivery passage  106  may pass through the second electrode connector portion  114  configured to connect the second electrode  102  to the shaft member  50 . 
     In the illustrated embodiment, electrodes  100 ,  102  may be configured to slide across a tissue surface in a presence of the RF energy from electrosurgical unit  10  and fluid  22  from the fluid source  20 . As shown, electrodes  100 ,  102  may be laterally and spatially separated (by empty space), and configured as mirror images in size and shape with a blunt distal end surface  116 ,  118  devoid of edges (to provide a uniform current density and treat tissue without necessarily cutting). More particularly, each distal end surface  116 ,  118  of electrodes  100 ,  102  may comprise a spherical surface, and more particularly comprise a hemispherical surface with an arc of 180 degrees. The spherical surface may be defined by a uniform radius along the arc, which may be in the range between and including 1.25 mm to about 2.5 mm. Electrodes  100 ,  102  may particularly comprise an electrically conductive metal, such as stainless steel. Other suitable materials may include titanium, gold, silver and platinum. 
     During manufacture of the device  30   a , electrical conductors  70 ,  72  are first installed and positioned with shaft member first body  60 . Thereafter, shaft member first body  60  and shaft member second body  62  may be joined by ultrasonic welding. Thereafter, electrodes  100 ,  102  may be joined to shaft member  50  by inserting male connector portions  112 ,  114  of electrodes  100 ,  102  into female connector portions  92 ,  94  of electrode receptacles  88 ,  90  of shaft member  50 . Prior to inserting male connector portions  112 ,  114  of electrodes  100 ,  102  into female connector portions  92 ,  94 , electrodes  100 ,  102  may be heated. In this manner, electrodes  100 ,  102  may heat and soften the female connector portions  92 ,  94  of electrode receptacles  88 ,  90  during insertion thereof. In this manner, which may be referred to as heat-staking, the insertion force may be reduced, and the plastic material defining female connector portions  92 ,  94  may flow to better join/grasp with the barbs and adhesively bond, as well as mechanically bond, to electrodes  100 ,  102 . In this manner a hermetic seal may be provided between electrodes  100 ,  102  and electrode receptacles  88 ,  90 . Alternatively, electrodes  100 ,  102  may be ultrasonically welded to electrode receptacles  88 ,  90  of shaft member  50 . 
     At the same time electrodes  100 ,  102  are joined to shaft member  50  by inserting male connector portions  112 ,  114  of electrodes  100 ,  102  into female connector portions  92 ,  94  of electrode receptacles  88 ,  90  of shaft member  50 , a distal portion  124 ,  126  of electrical conductors  70 ,  72  may be inserted into receptacles  128 ,  130  of electrodes  100 ,  102  to establish physical contact therewith for electrical communication. 
     As shown in  FIG. 12 , one way in which device  30   a  may be used is with the longitudinal axis of electrodes  100 ,  102  vertically orientated, and the spherical surfaces  116 ,  118  of electrodes  100 ,  102  laterally spaced adjacent tissue surface  202  of tissue  200 . Electrodes  100 ,  102  are connected to electrosurgical unit  10  to provide RF power and form an alternating current electrical field in tissue  200  located between electrodes  100  and  102 . In the presence of alternating current, the electrodes  100 ,  102  alternate polarity between positive and negative charges with current flow from the positive to negative charge. Without being bound to a particular theory, heating of the tissue  200  is performed by electrical resistance heating. 
     Fluid  22 , in addition to providing an electrical coupling between the device  30   a  and tissue  200 , lubricates surface  202  of tissue  200  and facilitates the movement of electrodes  100 ,  102  across surface  202  of tissue  200 . During movement of electrodes  100 ,  102 , electrodes  100 ,  102  typically slide across the surface  202  of tissue  200 . Typically the user of device  30   a  slides electrodes  100 ,  102  across surface  202  of tissue  200  back and forth with a painting motion while using fluid  22  as, among other things, a lubricating coating. Preferably the thickness of the fluid  22  between the distal end surface of electrodes  100 ,  102  and surface  202  of tissue  200  at the outer edge of couplings  204 ,  206  is in the range between and including about 0.05 mm to 1.5 mm. Also, in certain embodiments, the distal end tip of electrodes  100 ,  102  may contact surface  202  of tissue  200  without any fluid  22  in between. 
     As shown in  FIG. 12 , fluid couplings  204 ,  206  comprise discrete, localized webs and more specifically comprise triangular shaped webs providing fluid  22  between surface  202  of tissue  200  and electrodes  100 ,  102 . When the user of electrosurgical device  30   a  places electrodes  100 ,  102  at a tissue treatment site and moves electrodes  100 ,  102  across the surface  202  of the tissue  200 , fluid  22  is expelled from fluid outlet openings  108 ,  110  around and on surfaces  116 ,  118  of electrodes  100 ,  102  and onto the surface  202  of the tissue  200  via couplings  204 ,  206 . At the same time, RF electrical energy, shown by electrical field lines  208 , is provided to tissue  200  at tissue surface  202  and below tissue surface  202  into tissue  200  through fluid couplings  204 ,  206 . 
     Device  30   a  disclosed herein may be particularly useful as non-coaptive tissue sealer in providing hemostasis during surgery. In other words, grasping of the tissue is not necessary to shrink, coagulate and seal tissue against blood loss, for example, by shrinking collagen and associated lumens of blood vessels (e.g., arteries, veins) to provided the desired hemostasis of the tissue. Furthermore, the control system of the electrosurgical unit  10  is not necessarily dependent on tissue feedback such as temperature or impedance to operate. Thus, the control system of electrosurgical unit  10  may be open loop with respect to the tissue which simplifies use. 
     Device  30   a  disclosed herein may be particularly useful to surgeons to achieve hemostasis after dissecting through soft tissue, as part of hip or knee arthroplasty. The tissue treating portions can be painted over the raw, oozing surface  202  of tissue  200  to seal the tissue  200  against bleeding, or focused on individual larger bleeding vessels to stop vessel bleeding. As part of the same or different procedure, device  30   a  is also useful to stop bleeding from the surface of cut bone, or osseous, tissue as part of any orthopaedic procedure that requires bone to be cut. Device  30   a  may be particularly useful for use during orthopedic knee, hip, shoulder and spine procedures. Additional discussion concerning such procedures may be found in U.S. Publication No. 2006/0149225, published Jul. 6, 2006, and U.S. Publication No. 2005/0090816, published Apr. 28, 2005, which are assigned to the assignee of the present invention and are hereby incorporated by reference in there entirety to the extent they are consistent. 
     As established above, device  30   a  of the present invention inhibit such undesirable effects of tissue desiccation, electrode sticking, char formation and smoke generation, and thus do not suffer from the same drawbacks as prior art dry tip electrosurgical devices. The use of the disclosed devices can result in significantly lower blood loss during surgical procedures. Such a reduction in blood loss can reduce or eliminate the need for blood transfusions, and thus the cost and negative clinical consequences associated with blood transfusions, such as prolonged hospitalization. 
     In an alternative embodiment, device  30   a  may only have a single electrode  100  and comprise a monopolar device. 
     While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications can be made therein without departing from the spirit of the invention and the scope of the appended claims. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention which the Applicant is entitled to claim, or the only manner(s) in which the invention may be claimed, or that all recited features are necessary. 
     All publications and patent documents cited in this application are incorporated by reference in their entirety for all purposes to the extent they are consistent.