RELATED APPLICATIONS This application claims priority under 35 U.S.C. §119(e) firom application serial no. 60/013,251 filed March 11, 1996.

BACKGROUND OF THB INVENTION

Rotating surgical instruments that mechanically cot, shave, abrade and drill hard or soft tissue are well knov in the art and have proven, over time, to be quite useful. Such tools can be used in open or dosed surgical procedures to remove affected tissue. Typical rotating instruments used n these procedures include surgical drilling instalments, such as bone drills, and other rotating mffrhnriiral catting and shaving devices, such as morεellators and power shavers.

Conventional power shavers include an inner rotatable drive shaft having an abrading dement at a distal end. The drive shaft seats within a central lmnen of the shaver housing snch that the abrading dement is exposed at the distal end. The drive shaft couples to a motor which imparts rotary movement to the shaft The power shaver mechanically cats or shaves affected tissue by the direct mechanical contact of die abrading dement with the tissue.

One drawback of such devices is that the abrading edge of die instrument must be extremely sharp to enable effective mechanical cutting of the tissue. During the course of the surgical procedure, however, the abrading or cutting edge of the rotating tool tends to dull, thereby decreasing the cutting performance of the tool. When this occurs, the cutting tool must be replaced. The need for frequent replacement of the abrading portion of the device increases the

overall time necessary to conduct the surgical procedure while concomitantly increasing the cost of delivering die medical services and in stocking the replacement components for the medical device.

There thus exists a need in the art for rotary surgical devices that are able to provide effective cutting and abrading of tissue while minimizing or eliminating the need to replace selected components, such as the abrading element, of me device.

SUMMARY OF THE INVENTION

The present invention pertains to an electrosurgical apparatus that includes a rotary, tissue affecting device in the form of one or more rotating blades, a rotating drill, or a rotating shaving/abrading device that serves as an active, energy delivering electrode. The active electrode effectivdy cuts tissue at die surgical site without relying solely upon die mechanical cutting action of die tissue affecting device. The rotary surgical device can be in a form such that it is suitable for use in open or dosed surgery. The term "dosed surgery" is intended to include arthroscopic, endoscopic, hysteroscopic, laparoscopic, and resectoscopic surgical techniques. Closed surgical techniques typically utilize dongated instruments which are inserted into die patient's body through a small incision or a natural oriface, to allow a secondary instrument easy access to die surgical site. A variety of such surgical devices are well known in die art and are well described in the patent literature. Representative devices are described in U.S. Patent No. 4,842,578 (Johnson et al.), U.S. Patent No. 5,411,514 (Fucci et al.) and U.S. Patent No. 5,492,527 (Glowa et al.).

In its basic configuration, the electrosurgical device of the present invention includes a rotating, tissue affecting device having a distal, tissue contacting end which serves as an active, energy delivering electrode suitable for cutting tissue. The actual shape and structure of the device will depend upon the

purpose for which the device is used. For example, rotating cutting devices and arthroscopic shaving devices are well known in the art and the structure of such devices can be assumed. The rotating, tissue affecting device also includes a proximal end, usually in die form of an elongate drive shaft, which fits within a chuck or holder assembly. The holder assembly is then mounted to die base portion of an outer cannula that can include one or more electrically conductive contacts. The cannula can form part of an arthroscope, endoscope, hysteroscope, laparoscope, or resectoscope as is well known in the art.

The electrical contact is electrically connected at one end to one pole of a remote electrosurgical generator and at the other end to the elongate drive shaft of the tissue affecting device. The contact energizes die rotating shaft and dms die distal abrading end by transferring cutting energy from the electrosurgical generator to the drive shaft. Preferably, the rotating, tissue affecting device is coated with a non-conductive material (e.g., Teflon or Kynar) along an intermediate portion disposed between die area of die drive shaft that bears against the contact and the distal abrading end to electrically isolate the rotating device from the outer cannula.

The rotating electrosurgical device of die invention may be utilized in a monopolar or bipolar mode. When used in the monopolar mode die distal end of die rotating, tissue affecting device serves as die active, energy delivering electrode. The electrical circuit is completed by attaching a remote ground pad which serves as a return electrode to the patient's body, such as to the tiiigh or back.

When used in the bipolar mode the rotating, tissue affecting device again serves as the active, energy delivering electrode. One or more local electrodes, serving as the return electrode, are associated with, in proximity to or comprise die distal end of die housing that is disposed adjacent to the rotating,

tissue affecting device. It is understood that one or more active electrodes may be used in die bipolar mode.

During closed surgical procedures it is typically necessary to supply a fluid to a surgical site in order to distend die surgical area and to improve visibility for die surgeon. If a monopolar surgical system is to be used in a closed surgical procedure die fluid medium is typically non-ionic, otherwise the current generated by the active electrode will be dispersed by the medium, thus requiring die use of higher voltage and current levels. The use of higher voltages to deliver an appropriate level of current to effect tissue cutting subjects die patient to increased risks of harm. Specifically, the use of higher voltage levels can inadvertently harm tissue unrelated to die surgical procedure. The use of non-ionic fluid poses additional surgical risks, such as those associated with the inadvertent introduction of excess non-ionic fluid into the blood stream. The absorbed non-ionic solution can create dangerous dectrolytic disturbances within the patient, which can lead to cardiac arrhythmia, brain swelling and even sudden deatii.

Bipolar systems tend to be more advantageous since an isotonic solution (e.g., saline or Ringer's solution) can be used to distend die surgical site, rather than a non-ionic solution. The patient, therefore, is not exposed to potentially harmful levels of current since the isotonic medium does not disperse the current at die tip of die active electrode throughout the medium. Furthermore, the introduction of die isotonic solution into die patient's bloodstream does not create die dangerous electrolytic imbalances associated with absorption of the non- ionic solution.

The return electrodes typically are mounted on a distal, tissue contacting edge of the housing that forms the outer cannula. Alternatively, die return electrodes can be mounted on die distal end of a separate sheath tiiat is mountable over the outer surface of the cannula that forms part of the arthroscope,

endoscope, hysteroscope, laparoscope or resectoscope. This bipolar configuration is preferably used in closed surgical applications which employ ionic solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more fully understood from the following detailed description in combination with the drawings in which:

Figure 1 is an exploded view of a first embodiment of an electrosurgical device according to the present invention;

Figure 1A is an enlarged view of a portion of a tissue affecting device shown in Figure 1;

Figure 2 is a cross-sectional view of another embodiment of a tissue affecting device according to the present invention;

Figure 2A is an enlarged view of a portion of die tissue affecting device shown in Figure 2;

Figure 3 A is a side view of a portion of the electrosurgical cutting device shown in Figure 1;

Figures 3B and 3C are a series of cross sectional views of an electrosurgical deivce according to the present invention; and

Figure 4 is a side view of another embodiment of an electrosurgical cutting device according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to Figures 1 and 1A in which like elements are provided having like reference designations, an electrosurgical device 10 is shown to include a rotary, tissue affecting element 12 and an outer cannula 14. The tissue affecting element 12 serves as an active, energy delivering electrode, as is described in further detail below.

The tissue affecting element 12 includes a rotatable shaft portion 16 that is mounted within a chuck or holder assembly 18. The shaft 16 includes a distal end 16B and a proximal end 16A that is secured within a first receiving end 18A of the holder assembly. As illustrated, the shaft portion 16 can be in the form of an auger bit having a single spiral groove that extends from the proximal end 16A to the distal abrading end 16B. The anger bit is preferably coated with or encompassed by a non-conductive, material between the proximal end 16A and die distal aid 16B to electrically isolate the shaft from the outer cannula 14 whoa disposed therein. The distal abrading end 16B is preferably scored 20, i.e., die conductive coating is removed, at one or more locations to expose die electrically conductive material therebeneath. The illustrated score marks 20, shown in Figure 1A, form an electrosurgical abrading edge when die electrically conductive shaft is connected to an electrosurgical generator, as discussed in further detail below. The electrosurgical abrading edge delivers electrosurgical energy (e.g., radio frequency (RF)) energy to tissue.

The illustrated auger bit is preferably used when die affected tissue at die surgical site comprises relatively firm tissue. This device type is preferred since the auger bit presents a relatively large cutting surface to the tissue.

The one-piece holder assembly 18 of the tissue affecting element 12 preferably includes flanged portion 22 which forms part of the first receiving end 18A, and a second axial hub portion 26. The hub portion 26 typically has a

diameter that is larger than die neck 22A of the flanged portion 22. Preferably hub portion 26 includes a suction aperture 24 that extends transversely tinough the hub portion. The hub portion 26 terminates in a fluted extension 28 that is captured within a spring loaded cap assembly 30. The cap assembly is known in die art and includes an outer cylindrical body that has secured therein a tension spring (not shown). The fluted portion 28 preferably includes a radially outwardly-extending flange (not shown) which seats within and is captured by the spring loaded cap assembly 30. The cap assembly 30 is preferably sized to seat within d e rotor portion of a conventional drive motor handle, such as that manufactured by Concept, Inc., of California, U.S.A. The fluted portion 28 further includes an axially extending (to die left in Figure 1) base tab tiiat is adapted to seat within a corresponding U-shaped seat witibin the motor handle. The drive motor handle preferably imparts a rotary motion to the holder assembly 18, dms rotating die shaft portion 16 of die tissue affecting dement 12. The cap assembly 30 resiliendy and telescopically moves along die longitudinal axis 32 of the shaft 16 to prevent endplay and runout of die drive mechanism of the motor handle from being transferred to die shaft 16 during operation.

Figure 2 illustrates a second embodiment of die tissue affecting device 36 according to the present invention. Identical parts will be designated throughout the views by like reference numerals plus a superscript prime. The device 36 includes a shaft portion 38 that is mounted within a holder assembly 18' . The shaft portion 38 includes a substantially cylindrical outer body 38A that defines a central lumen 40. A proximal end 38B of me shaft 38 seats within the first receiving end 18 A' of the holder assembly 18*. The lumen 40 extends along longitudinal axis 32 and is preferably in fluid communication with the suction aperture 24' formed in the hub portion 26'. This specific fluid arrangement allows the electrosurgical device 10 to remove fluid and tissue debris from the surgical site by applying a vacuum to the suction aperture 24' . The applied vacuum draws fluid and debris

through the central lumen 40 and the aperture 24' and thus away from the surgical site.

The tissue affecting device 36 further includes a distal abrading end 38C having a serrated opening 42 that communicates with the central lumen 40. The shaft 38 is preferably covered by or coated with a non-conductive material between the proximal end 38B and die abrading end 38C to electrically isolate the shaft from the outer cannula 14. The illustrated abrading end 38C is preferably free of any insulating material to allow the shaft to function as an active, energy delivering electrode when energized by an electrosurgical generator.

The tissue affecting device 36 tiius forms a simple and elegant cutting surface that is preferably used when the affected tissue at the surgical she comprises relatively soft tissue.

Those of ordinary skill will appreciate that alternative shaft designs can be used in conjunction with the teachings of die present invention. For example, the shaft can have a burr welded on die distal end of the shaft, which serves as an RF abrading end. Other designs can indude d e formation of a dremel head on the distal end of die shaft. The dremel head embodiment is preferably used when die affected tissue comprises ultrafirm tissue. As illustrated in Figure 2, the shaft of die tissue affecting device can also include a central lumen to allow the removal of liquid and tissue debris from the surgical site. According to another practice, die auger bit design of Figure 1 can be used to remove fluid and tissue debris from the surgical site by the rotating action of die shaft 16. The specific design of the shaft and abrading end are not critical features of die present invention, provided that the shaft includes an abrading end having a selected surface free of insulation to form a relatively high current density RF cutting edge.

With reference to Figures 1 and 3A-3C, die outer cannula 14 includes a base portion 48 that mounts an elongate outer sheath 50. The sheath 50 extends entirely or partly through a mounting bore 52, and preferably terminates prior to the commutator 60. The outer sheath 50 has a central lumen 62 that extends between a proximal end 50A which seats within bore 52 and a distal end 50B. The central lumen 62 preferably has a diameter slightly larger than die diameter of the shaft 16 of the tissue affecting element 12 to allow the shaft 16 to fit easily therein. The outer sheath 50 further includes an opening 64 formed in the distal end 50B. The opening 64 exposes die abrading end 16B of the shaft 16 to the tissue at the surgical site to effect tissue cutting during use.

An insulation material 66, e.g., a non-conductive coating, covers the outer portion of the sheath 50 between the proximal and distal aids 50A, 50B. Although not illustrated, it is understood that a non-conductive coating or material may be applied to the inner portion of sheath 50 as well. In one embodiment, me distal end 50B of the sheath 50 is exposed, i.e., is free of die non-conductive coating, and thus may serve as a return electrode when die electrosurgical device 10 is operated in me bipolar mode. Those of ordinary skill will appreciate that the electrosurgical device 10 can also operate witiiout die non-conductive layer.

The base portion 48 of the outer cannula 14 includes a central bore 52 that extends between first and second ends 56A, 56B. The base portion 48 further includes a second bore having an aperture 54, illustrated in Figure 3A, which extends into me base portion 48 and which communicates with bore 52. In a preferred embodiment, a longitudinal axis of the second bore is transverse to a longitudinal axis of bore 52. The transverse aperture 54 seats the commutator 60, which communicates the RF energy between the electrosurgical generator and the tissue affecting element. The commutator 60 preferably includes a resilient steel J - wire 68 that is electrically coupled to an electrically conductive button portion 70. According to one preferred embodiment, the J-wire 68 bears against the conductive

outer portion of die rotary shaft 16 axially below, i.e., to the left in Figure 1, the non-conductive coating 66 disposed on die sheath. The button portion 70 forces die J-wire 68 into contact w h the shaft 16 to maintain electrical contact with the shaft 16 during operation. The operation of commutators are known in me art and need not be described further.

The base portion 48 also includes a first electrical port 72 that is adapted to seat a corresponding electrical lead which is coupled to the active output of die electrosurgical generator (not shown). The electrical port 72 is also electrically coupled to a conductive tab 74, which in turn is electrically coupled to die button portion 70 of the commutator 60. The electrical circuit pathway formed by die mating engagement of the J-wire 68, the button portion 70, die tab 74, and the electrical port 72 energizes die shaft 16, thus forming the active energy- delivering electrode of die invention.

The base 48 further includes an electrically conductive dip 78 that substantially surrounds and engages die outer sheath 50 below the non-conductive coating 66. The clip 78 is electrically coupled to a second electrical port 80 that is adapted to seat die other electrical lead of die electrosurgical generator. The conductive cup 78 and die port 80, in conjunction whh die outer sheatii 50, form me current return pathway for the electrosurgical device when operated in die bipolar mode.

With further reference to Figures 1 and 3A-3C, die first end 56A of the base portion 48 can have a conically shaped cavity 82 that tapers inwardly towards a second axially spaced cavity 84. The conically shaped cavity 82 is preferably shaped complementary to the hub portion 26 of die holder assembly. Specifically, the conically shaped cavity 82 includes a shoulder 82 A that bears against the sloped front portion 26A when the tissue affecting element 12 is disposed within tiae outer cannula 14. The second cavity 84 is preferably

configured to seat the flanged portion 22 of die holder assembly 18. In the illustrated embodiment, the flanged portion 22 of die element 12 is retained within die base 48 by the mating engagement of die flange 22 with die sloped and chamfered end 84A of die second axial cavity 84. This mating engagement prevents die tissue affecting device from dislodging from the outer cannula 14 during use.

The rotary electrosurgical device 10 of die invention can be assembled by inserting the shaft 16 of die tissue affecting element 12 within die central lumen 62 of the outer cannula 14. The holder assembly 18 is secured within die base 48 of die outer cannula 14 by the mating engagement of die flanged portion 22 of the holder assembly 18 with die sloping and diamfered end of cavity 84, as well as the engagement between the sloping surface 26A of the hub portion 26 which bears against the shoulder 82A of die cavity 82. In this position, the rotatable shaft 16 contacts the resilient J-wire 68 of the commutator 60. The outer cannula dms functions as the carrier for the tissue affecting dement 12 of the present invention.

Once die tissue affecting dement 12 is secured within die outer cannula 14, me entire assembly is secured to the drive handle motor by inserting die protruding cap assembly 30 and die hub portion 26 into die receiving end of die handle. The base tab formed on die end of die fluted section 28 slides between a corresponding U-shaped seat within die motor handle. The drive motor, when actuated, imparts a rotary motion to the tab and thus die shaft portion 16 of die tissue affecting device.

In the embodiment of Figure 1, the distal abrading end 16B of the shaft aligns with the opening 64 formed in the distal end 50B of the outer sheath 50. This opening allows the rotary, tissue affecting element 12 to contact and thus act upon tissue at the surgical site.

The electrical leads of die generator are connected to one or both of die electrical ports depending upon the selected mode of operation. For example, in the monopolar mode, die electrical lead associated whh die active output of the generator is connected to die electrical port 72. This electrical connection energizes the shaft and thus forms an active rotary electrode, as illustrated in

Figures 1 and 3C. A remote ground pad is secured to the patient to complete the electrical circuit. Alternatively, die other electrical lead associated with the generator can be coupled to the second electrical port 80 to form a bipolar rotary electrosurgical instrument in which an exposed (i.e., non-insulated) portion of sheath 50 serves as die return electrode.

A vacuum line can be connected to an appropriate pressure fitting formed on die drive motor handle to remove tissue and fluid from me surgical site. The pressure fitting of the drive motor is preferably in fluid communication with die suction.apertnre 24 formed in die hub portion 26 of the tissue affecting element 12. The aperture 24 in turn is in fluid communication with the central lumen 62 of the device and/or with the central lumen 40 of the tissue affecting device of Figure 2. Consequendy, a vacuum applied to the pressure fitting draws tissue debris through the central lumen and aperture and dms away from me surgical site.

In operation, the shaft 16 of the tissue affecting device is energized by actuating die electrosurgical generator. The rotatably actuable cutting element 16 is preferably coated over a substantial portion of its length with an insulating material. Preferably only the tissue contacting cutting edges of die abrading end remain uncoated of the insulating material, thus forming an active, energy delivering electrode. In one embodiment, the electrosurgical energy supplied by die generator is communicated dirough nearly the entire length of die rotating cutting element to me abrading end.

The shaft 16 of the element 12 is rotatably actuable by activating the drive-motor handle, which imparts a rotary motion to the shaft 16. As the shaft portion of die rotatable cutting element rotates, it is maintained in contact whh a suitable electrical contact, e.g., J-wire 68, thus communicating electrosurgical energy supplied by die remote generator to die abrading end of die device.

In the embodiment of Figure 1, die scored ends 20 of die tissue affecting device form an electrode that delivers radio frequency (RF) energy to target tissue. As the shaft 16 of the element 12 rotates, die movement of die energized abrading end towards die outer sheath creates a high energy arc discharge that serves to sever tissue at the surgical site. The excised tissue can be removed from the site through die lumen 62 of the cannula by die continuous rotary motion of die anger-bit type shaft 16. When the excised tissue reaches the holder assembly 18, me vacuum force applied to the drive motor handle draws the tissue through the suction aperture 24 and handle, and to a remote collection site.

The exposed outer portion of the sheath serves as the return electrode and thus coπφletes the dectrical circuit padiway necessary to properly dissipate the electrosurgical energy applied to the surgical site by die active electrode. Alternatively, the dectrical lead of die generator which is coupled to the second dectrical port 80 is disengaged and a remote ground pad is secured to the patient. The ground pad completes the circuit padiway and serves as the return electrode.

In the bipolar mode, die foregoing rotary electrosurgical device is configured such that the active and return electrodes are electrically isolated from each other. Specifically, the rotating shaft of the tissue affecting device, which is made from a conductive material, is coated or covered over virtually all of its length with an insulating material to electrically isolate the shaft from the outer sheath of die cannula 14. The shaft is then disposed in electrical communication

with die active pole of die electrosurgical generator by way of die J-wire electrical contact 68, or a similar means.

If the tissue affecting device 36 of Figure 2 is mounted within die outer cannula 14, the exposed serrated end of the device 36 serves as the active energy-delivering electrode. In this embodiment, the shaft 38 of the tissue affecting device 36 is actuated by activating die drive-motor handle. The movement of the positively energized abrading end 38C towards die isolated outer sheath 50 creates a high energy arc discharge that serves to incise tissue at the surgical site. Hence, as die shaft 38 rotates, the tissue affecting device 36 cuts tissue by the mechanical action of the abrading end and by die electrosurgical energy (e.g., RF energy) delivered to the tissue by die energized cutting edge. The tissue cut by the device 36 is then removed from the surgical site via die central lumen 40 of the device 36. Since die central lumen 40 is in fluid communication with die suction aperture 24', the tissue debris is drawn tiirough die lumen 40 and aperture 24' by the vacuum force applied to die drive-motor handle.

Figure 4 illustrates another embodiment of die rotary electrosurgical device 100 of the invention. The base 102, outer sheath 104, and tissue affecting device 106 are similar or identical to die parts described above with respect to Figures 1-3C which correspond to these parts. During bipolar operation, an electrical lead connected to one pole of die electrosurgical generator is connected to die outer sheath 104 through die electrical connection junction 110, and die exposed portions of die tissue affecting device 106 and die outer sheath 104 are electrically isolated from one another. Portions of the outer sheath and connection junction 110 are covered by a coating of non-conductive material to insulate die device and to ensure electrical isolation of die outer sheath and die tissue affecting device.

The illustrated rotary electrosurgical device 100 operates in a manner similar to that described above.

The foregoing rotary electrosurgical devices are adapted for use in closed surgical procedures. More specifically, the devices are adapted to be inserted within a housing of a typical closed surgery access instrument such as an arthroscope, endoscope, hysteroscope, laparoscope, or resectoscope. The rotary tissue affecting element 12, 36 of die invention can be disposed within die housing of die access instrument such that the abrading end 16B, 38C of die tissue affecting devices are able to access tissue to be treated through the cutting die cutting aperture 64 of die outer sheath 50.

Having described preferred embodiments of die invention, it will now become apparent to one of ordinary skill in the art that other embodiments incorporating me concepts herein disclosed may be used. It is felt, therefore, that these concepts should not be limited to disclosed embodiments but rather should be limited only by d e spirit and scope of the appended claims. The contents of all cited references are expressly incorporated herein in their entirety.

What is claimed is: