WO1997034534A1

WO1997034534A1 - Method and device for tissue vaporization and extraction

Info

Publication number: WO1997034534A1
Application number: PCT/US1997/004160
Authority: WO
Inventors: George M. Savage; Donald L. Alden; Jeffrey J. Christian; Arnold J. Kresch
Original assignee: Femrx, Inc.
Priority date: 1996-03-18
Filing date: 1997-03-13
Publication date: 1997-09-25

Abstract

The present invention provides methods and devices for extracting tissue from internal surgical sites. The method comprises removing tissue from the uterus by applying radio frequency electrical power to the tissue so that a portion of the removed tissue is vaporized. While removing the tissue, the depth of tissue removed is viewed and the removed tissue is evacuated from the uterus. The radio frequency power is applied by an electrosurgical member (202) of a probe (200), the probe also having an imaging mechanism (222) and an aspiration lumen (218). In some embodiments, the removed tissue is either fragmented or morcellated within the uterus to avoid clogging of the aspiration lumen (218). In other embodiments, substantially the entire removed tissue is vaporized.

Description

METHOD AND DEVICE FOR TISSUE VAPORIZATION AND EXTRACTION

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Patent Application Serial No. 60/013,637, filed March 13, 1996; and is also a continuation-in-part of U.S. Patent Application Serial No. 08/542,289, filed October 12, 1994, which is a continuation-in-part of U.S. Patent Application Serial No. 08/322,680, filed October 13, 1994, which is a continuation- in-part of U.S. Patent Application Serial No. 08/136,426, filed October 13, 1993, which issued as U.S. Patent No.

5,456,689, and is also a continuation-in-part of U.S. Patent Application filed August 29, 1996, (Attorney Docket No. 16944- 001210) , which is a continuation of U.S. Patent Application Serial No. 60/008,226, filed November 8, 1995; the full disclosures all of which are incorporated herein by reference

BACKGROUND OF THE INVENTION

This invention relates to electrosurgical removal of tissue, and in particular, provides methods and devices which remove a target tissue from a surgical site by vaporizing at least a portion of the target tissue.

Electrocautery has been in use for many years as a general surgical tool, such as for trans-cervical fibroid removal. The uterus is first flooded with a nonconductive fluid, such as sorbitol-mannitol fluid or the like under sufficient pressure to separate the walls of the uterus and render the surgical site suitable for optical fiber observation. This procedure is generally described as uterine cavity distension. During this flooding, an electrocautery surgical tool is inserted into the uterus through the cervix. Electrical current at high voltage settings typically an alternating current about 750 KHz and 2000-9000 volts; is transmitted from a cutting surface of the surgical instrument to the surgical site. The cutting surface usually consists of a wire or solid shape. The transmission of current to the uterus is monopolar, and the circuit is completed by a conductive path to the power unit through a conductive pad applied to the patient's skin.

The electrical current is concentrated at the cutting surface. Heat generated from the resistance of tissue to the flow of electrical current is high enough to vaporize cells near the cutting surface. Thus, a cut is made with very little physical resistance to the cutting motion. Heat from the cut cauterizes small blood vessels so that visibility and control remain good.

In the cautery mode and during uterine cavity distention, the same electrical resistance heating is used at lower power settings to cauterize tissue and to kill selected areas . Cautery electrodes can be larger in area so as to treat broader surfaces . Cautery is used in gynecology to ablate the endometrial lining of the uterus. This procedure is often performed using a conductive roller similar in shape to a football which heats a wide swath along the inner surface of the uterus .

Electrocautery tools are compact and require a minimum of area in which to work. Since the tool only cuts when the power is turned on, they can be safely maneuvered into small areas. Electrocautery has found broad general application in the treatment of enlarged prostate glands, and in the removal of uterine fibroids.

A secondary effect of the removal of tissue, particularly in the areas of prostate reduction and fibroid removal, is that severed morsels remain in the working area and must be periodically flushed or suctioned away to preserve the required visibility necessary for surgery. The clean, well controlled action of electrocautery is now slowed by the need to remove fragments which obstruct visibility. This required removal prolongs the surgical procedure.

For this reason, it would be desirable to provide improved methods for removal of tissues from an internal surgical site, as well as electrosurgical devices which allowed such improved methods. It would further be advantageous if these improved electrosurgical methods and devices allowed the surgeon to monitor the tissue removal process while it was underway, particularly if the removal of tissues and their evacuation were combined into a simultaneous, continuous process to avoid any interruption of the surgical procedure.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a method for extracting tissue from the uterus, the method comprising removing tissue from the uterus by applying a radio frequency to the tissue so that a portion of the removed tissue is vaporized. While removing the tissue, the depth of tissue removed from the uterus is viewed and the removed tissue is evacuated from the uterus. Preferably, the radio frequency is applied by an electrosurgical member of a probe, the probe also having an imaging mechanism and an aspiration lumen. Ideally, these probe elements provide an irrigation flow path that maintains image quality during simultaneous removal and evacuation.

Generally, a member is translated through uterine tissue while the member is energized with the radio frequency power to vaporize tissue adjacent the member. In some embodiments, the member severs unvaporized tissue from the uterus, the severed tissue ideally being either fragmented or morcellated within the uterus to avoid clogging of the aspiration lumen. In other embodiments, substantially the entire removed tissue is vaporized, preferably with a member comprising at least one rollable element. Particularly advantageous rollable elements direct energy into the uterine tissue to fragment and remove a large swath of tissue with each pass of the member, for example, rollable elements which have spurs, or a plurality of fanned out disks.

In another aspect, the present invention provides an electrosurgical device comprising a shaft having a proximal end, a distal end, an aperture near the distal end, and an aspiration lumen between the aperture and the proximal end. An electrosurgical member is disposed near the apert -e, the member vaporizing tissue from an internal surgical site when the electrosurgical member is energized and translated through a target tissue. An imaging mechanism disposed on the shaft is oriented toward the electrosurgical member so as to view the target tissue without substantial interference from tissue debris when the electrosurgical member vaporizes tissue while the vaporized tissue is being aspirated through the aperture.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present methods and the accompanying surgical instruments will become more apparent after referring to the following specification and attached drawings in which:

Fig. IA is a perspective view of the drive housing with probe attached illustrating the housing and probe in partial section for understanding of the operative portions of the instrument; Fig. IB is a perspective of the drive housing H with probe attached illustrating the housing grasped in the hand of the surgeon (shown in broken lines) demonstrating the surgical instrument manipulation of the rigid probe to dispose the elongate aperture at the surgical site, trigger finger manipulation of the cutting head relative to the viewing fiber and ultrasound transducer, and finger actuated aspiration during surgery;

Fig. 2 is a section at the distal end of the probe illustrating the rigid shaft, elongate cutting aperture, infusion lumen, electrocautery cutting head, rotating cutting head driving tube with integral aspiration lumen, viewing optical fiber, and ultrasound transducer;

F g. 3A, 3B and 3C are respective sections of a uterus respectively illustrating the probe with an obturator during insertion for surgery, the instrument with rotating shaft and cutting head being inserted to the probe; and the insertion of the optical fiber for completion of the assembled probe; Fig. 4 is a section similar to the sections of Figs. 3A-3C illustrating the working end of the instrument at an operative site;

Fig. 5 is a schematic perspective view of an alternative tissue resection device according to the principles of the present invention;

Fig. 6 is a detailed cut-away side view of a tissue resection device patterned according to the schematic of Fig. 5; Fig. 6A is an enlarged cross-sectional view of the distal end of the tissue resection device of Fig. 6;

Fig. 7 illustrates an alternative method for removing tissue from the uterus using a device similar to the embodiment of Fig. 6; Fig. 8 is a perspective view of yet another probe according to the principles of the present invention, showing a proximal handle and several of the probe system connections;

Fig. 9 illustrates a probe system, including the probe of Fig. 8; Fig. 10 illustrates a method of use of the probe of

Fig. 8 for transcervical fibroid removal from the uterus;

Figs. 11 and 12 illustrate the axial cutting motion of the cutting member and morcellator, and also show the transverse arched wire supporting and fanning-out the rolling elements of the vaporizing member at the distal end of the probe of Fig. 8;

Figs. 13A and 13B illustrate a disk-shaped rolling element for use in the vaporizing member of the probe of Fig. 8; Figs. 14-14B illustrate alternative rolling elements having a spurred cross-section for use in the vaporizing member of the probe of Fig. 8.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS Referring to Fig. IA, surgical probe P is shown mounted to housing H. In understanding this embodiment of the present invention, the probe P will first be discussed with respect to the embodiment of Fig. 2. Thereafter, the construction and operation of the prooe from drive housing H in the hand of a surgeon will be discussed. Finally, alternate embodiments of the probe and cutting head as well as the capture of debris from the surgical site will be set forth.

Referring to Fig. 2, probe P is illustrated only at its distal and surgical end. Probe P is rigid having a blunted forward end 14 with an enlarged end 16 for fully accommodating the section of cutting head C. Exposure for surgery of cutting head C occurs at elongate slot 18 with view of the cutting head C during surgery within slot 18 being provided by optical fiber F at the proximal end of the slot.

An electrocautery cutting head C is provided. Head C includes electrically conductive cutting edges 20 which are radially exposed from the cutting head C for surgical resection when head C is rotated in the direction of arrow 22. The electrical current is concentrated at the cutting surface, and heat generated from the resistance of tissue to the flow of electrical current is high enough to vaporize cells near the cutting surface. Head C is hollow and communicates to rotating driving tube 30 with interior aspiration lumen 25. An ultrasound transducer T rotates with cutting head C and sends and receives acoustical signals through wire 35. This transducer can measure remaining uterine wall thickness immediately after surgery when head C is in elongate slot 18 drawn proximally or distally of elongate slot 18 or at any intermediate position with respect to the slot.

Cautery alone utilizing probe P can occur. Specifically, by rotating cutting head C opposite to arrow 22, electrocautery cutting heads 20 pass in a blunted and non incisive path over the flesh while appymg radio frequency electrical power. Cautery results.

Having generally discussed the construction of the probe, attention can now be directed to handle H. Referring to Fig. IA, handle H includes DC motor 40 electrical connections 42--it being recognized that reversal in motor polarity causes reversal in motor direction. Electrocautery connection is routed via a standard cautery power supply through conduit 41 to a journal bearing connection (see Fig. IA) . Acoustical transducer T (seen m Fig. 2) at cutting head C sends and receives electrical signals through lead 43. A conventional slip coupling--not shown--is provided to wire 35 in tube 30 to lead 43.

Motor 40 is mounted to plate 45 and provides driving rotation at toothed pulley 47. Belt 46 drives toothed pulley 48 which in turn rotates drive tube 30 through a quick disconnect coupling. This quick disconnect coupling is the point of removable attachment of the probe. (See Fig. IA)

Drive tube 30 is of constant length. Forefinger trigger 50 attaches directly to plate 45 which is mounted for sliding translation interior of handle H. By movement of trigger 50 relative to housing H, corresponding movement of cutting head C occurs along elongate slot 18. Video camera coupler 55 communicates to fiber F having illumination strands for viewing of the applicable surgery.

Still referring to Fig. IA, the fluid circuit for maintaining uterine cavity distention is only illustrated in pertinent part. It is presumed that standard technology will be used to maintain required pressure for uterine cavity distention through inlet conduit 61. Inlet conduit 61 communicates to probe P in the infusion lumen 62. By maintaining a constant pressure sufficient to establish uterine distention, required inflation is maintained in the organ--here the uterus--m which the operation occurs.

Referring to Fig. IB, the surgical ergonomics of housing H can be appreciated. Taking the case of a right handed surgeon, housing H at bottom surface 70 is held by hand S with thumb 72 opposing the third, forth and fifth fingers

74, 75 and 76. Forefinger 73 grips trigger 50 and by movement of finger 73 relative to housing H causes inward and outward traverse of cutting head C relative to elongate slot 18 of probe P. Middle finger 74 depresses valve 66 to cause applicable aspiration for example when view from eyepiece 55 indicates obstruction. Thus, flushing of sorbitol-mannitol solution distending the uterus can occur at intermittent and successive intervals as required by the surgical procedure. Insert of the instrument is easy to understand. Referring to F g. 3A, probe P with an obturator 0 is inserted to uterus U. Thereafter, obturator 0 is withdrawn, and housing H with cutting head C threaded (See Fig. 3B) . Once this insertion is made, fiber F is thereafter inserted for visualization of the surgical site (See Fig. 3C) . Operative movement of the instrument can thereafter occur as illustrated m Fig. 4.

The instrument in use can be visualized m the uterine section of Fig. 4. Probe P is shown with blunt end 14 within uterine cavity 80. This cavity is flooded with sorbitol-mannitol solution 82 so as to dispose lining for surgery. In the preferred method, cutting head C is disposed at C . Under the guidance of fiber F, probe P is maneuvered to the surgical site. Assuming resection, cutter head C is drawn proximally of elongate slot 18 in probe P. With the preferred construction illustrated in Fig. 4, three occurrences follow.

First, and starting with cutting head C distally of elongate slot 18, view of the tissue before resection is provided. Secondly, and with traverse of cutting head C, surgical resection occurs. Thirdly, and immediately m the wake cf the required resection, acoustical transducer T interrogates uterus U immediately after the surgery. It will be remembered that evacuation of fluid occurs directly from the cutting edges of cutting head C to rotating tube 30 with its aspiration lumen 25. Accordingly, flushing of chips and morsels is immediate the surgical site 90 with minimal chance for clouding the required view through fiber F.

The invention also provides an alternative embodiment of a tissue resection/ablation device 200. The device 200 is illustrated schematically m Fig. 5. While the device 200 is particularly advantageous for transcervical fibroid removal, removal of myometrium, and removal of endometrium, the device 200 may find other uses including those previously listed above and further including joint arthroscopy. For purposes of convenience, the device 200 will be described with reference to treatment of the uterus. However, the invention is in no way limited to only this type of application.

The device 200 includes an electrosurgical member 202 that is shown schematically in the form of an arch. The electrosurgical member 202 can conveniently be formed from an electrically conductive wire, metal strip, or the like, and can be fashioned in any shape depending on the particular application. Fashioning in the form of an arch is advantageous when removing fibroid tissue from the uterus because strips of tissue can rapidly be removed by translating the electrosurgical member 202 througn the tissue. Current is provided to the electrosurgical member 202 through a wire 204 which is m turn connected to an electrosurgical unit. The electrical current is concentrated at the cutting surface, and heat generated from the resistance of tissue to the flow of electrical current is high enough to vaporize cells near the cutting surface.

When electrosurgically removing tissue using prior art methods, the surgical site within the uterus rapidly fills with debris created from the removed tissue. Removal of this debris becomes_ imperative to allow the surgeon to maintain a clear view of the operation site. Prior art attempts to remove such debris include "sweeping" away the debris between cutting strokes, and periodically removing the electrosurgical device from the uterus to flush or suction away the debris. In the present invention, the removed tissue is immediately evacuated from the uterus by directing the tissue strips from the electrosurgical member 202 and into a chopping or severing mechanism 206. The chopping mechanism 206 in turn rapidly reduces the size of the tissue strips so that the tissue can be suctioned through the device 200 and removed from the uterus. In this way, tissue removed by the electrosurgical member 202 is evacuated from the surgical site as rapidly as the surgeon can cut the tissue. The amount of debris created in the uterus is drastically reduced, and the time consuming steps of "sweeping" away tissue or removing the electrosurgical device from the uterus for flushing or suction is eliminated.

The tough and gristly nature of fibroid tissue makes it difficult to remove from the uterus with conventional knife-edged instruments. Use of the electrosurgical member

202 has proven to be effective in such removal. However, once removed by the electrosurgical member 202, the fibroid tissue becomes easier to process, and a conventional arthroscopic cutter can be employed to chop or severe the tissue into smaller morsels. Suitable arthroscopic cutters are described in U.S. Patent Nos. 4,274,414 and 4,203,444, the disclosures of which are herein incorporated by reference. Briefly, such cutters include a rotating concentric tube having a shaving port into which the tissue is directed. The rotating blade chops the fibroid tissue into small transportable morsels or chips which can then be removed from the uterus through the concentric tube by suction. Although such cutters are preferred, a variety of different chopping mechanisms can be employed including reciprocating blades, grinders, and the like, a necessary requirement being that the mechanisms chop, severe or reduce the tissue into smaller morsels for evacuation. A motor 208 is provided to rotate the chopping mechanism 206. The motor 208 further includes a vacuum valve and an associated vacuum port for providing suction to remove the chopped tissue from the uterus.

To assist in directing the strips of tissue removed by the electrosurgical member 202 towards the chopping mechanism 206, an end cap 210 is provided just distal to the electrosurgical wire 202. In this way, tissue removed when translating the electrosurgical member 202 is directed by the end cap 210 into the chopping mechanism 206. The chopping mechanism 206 in turn chops the tissue as it is fed from the end cap 210 so that substantially all tissue removed by the electrosurgical member 202 is chopped and removed from the uterus. Operation of suction and motor 208 without electrocautery allows the device 200 to extract loose floating debris that may have escaped the initial cutting/extraction process. Visualization of the surgical site during operation of the electrosurgical member 202 can optionally be provided by a fiber optic scope 222 near the electrosurgical member 202. The fiber optic scope 222 provides conventional visual feedback through an eyepiece 224 to which a video camera is commonly coupled for display on a video monitor and for creating a tape record of the procedure. An alternative to the fiber optic scope 222, ultrasonic transducer 220, can be used separately or can be used together with the scope to provide both conventional optical visualization and ultrasonic visualization of uterine wall thickness. Standard optical scopes may also be used in place of the fiber optical scope 222.

Referring to Fig. 6, an alternative embodiment of a tissue resection device will be described. The device of Fig. 6 is patterned after the schematic of Fig. 5. For purposes of convenience, the embodiment shown in Fig. 6 will use the same reference numerals as used to schematically describe the tissue resection device 200 in Fig. 5. The device 200 includes an elongate body 212 having a distal end 214 and a proximal end 216. The elongate body 212 houses the chopping mechanism 206 and holds the electrosurgical member 202 in a fixed position relative to the chopping mechanism 206. To position the elongate body 212 and the fiber optic scope 222 within the sheath 226 (shown cut away to illustrate positioning of the components) , a guide 230 is provided within the sheath 226. (For purposes of clarity, the irrigation lumen 228 and wire 204, which pass through channels in the guide 230, have been omitted.) The guide 230 is slidable within the sheath 226 and also provides a seal between the components and the sheath 226 so that distention pressure can be maintained inside of the uterus during operation. The guide 230 is preferably constructed of plastic, but can alternatively be constructed of a variety of other materials including stainless steel, brass, aluminum, and the like. The guide 230 is preferably permanently fixed to the outside of the elongate member 212 and includes O-rings 232 and 234 for . sealing the guide 230 to the sheath 226 and scope 222. The sheath 226 will be preferably constructed of stainless steel which can be sterilized and reused.

The electrosurgical member 202 will preferably comprise an electrosurgical wire that is formed into a loop, an arcn, or other suitable geometry. The electrosurgical wire 202 is attached to the outside of the elongate body 212 and is positioned above an aperture 218 in the elongate body 212 which provides access to the chopping mechanism 206. The end cap 210 is fixed to the distal end 214 of the elongate body 212 so that strips of tissue removed by the electrosurgical wire 202 are directed by the end cap 210 into the aperture 218.

An electrically conductive area 236 (or plurality of areas) s provided on the outside surface of the end cap 210 that can be connected to the same electrosurgical unit used to provide current to the electrosurgical wire 202. When actuated, the electrically conductive area 236 can be applied to bleeding tissue to promote coagulation to stop bleeding or can be used for endometrial ablation. When used for ablation, the end cap 210 will preferably be constructed of a ceramic, and the electrically conductive area 236 will preferably be a metallic surface on the cap 210 that is connected by a separate wire to the electrosurgical unit.

The elongate body 212 includes a central lumen 237 extending between the distal end 214 and proximal end 216.

Held within the lumen 237 is the chopping mechanism 206. As shown best in Fig. 6A, the chopping mechanism 206 will preferably include a concentric rotating tube 240 disposed within the lumen 237. A shaving port 238 is formed m the wall of the tube 240 and is generally aligned with the aperture 218 of the elongate body 212. An edge 239 of the shaving port 238 and an edge 241 of the aperture 218 are sharpened so that any tissue drawn through the aperture 218 and shaving port 238 are sheared upon rotation of the concentric tube 240. In Fig. 6A, the rotating tube 240 is shown with the shaving port 238 facing away from the aperture 218. The triangle area TR is an opening between the edges 239 and 241. As the tube 240 is rotated, the edge 239 of the shaving port 238 is translated across the edge 241 of the aperture 218 until the triangle area TR disappears. Any tissue extending through both the shaving port 238 and the aperture 218 is sheared by the edges 239 and 241. Upon each revolution of the tube 240, another morsel of tissue is sheared.

The concentric tube 240 is rotated by the motor 208 (not shown) held within a housing 242. The housing 242 includes vacuum ports for connection to a house vacuum and associated vacuum valves for regulating suction. The suction is applied through the tube 240 thereby allowing the chopped morsels to be evacuating from the uterus.

Referring to Fig. 7, an additional method for resecting will be described with reference to a still further embodiment of a tissue resection device 200". The resection device 200" is essentially identical to the tissue resection device 200' described in Fig. 6, except for the configuration of the end cap. In the tissue resection device 200", an end wire 250 is provided at the distal end 214 of the elongate body 212. Use of the end wire 250 is advantageous in that it allows an optical viewing path for the optical scope 222 beyond the distal end 214 of the device 200". This allows for viewing of the area where the device 200" is being positioned in preparation for a cut. A shell 252 is welded or bonded to the elongate body 212, the shell directing removed tissue into the chopping mechanism 206. Optionally, shell 252 can also be provided with electrically conductive areas to cauterize or thermally ablate tissue.

Initially, the sheath 226 is inserted into the uterus using an obturator (not shown) as previously described. The obturator is then removed and the device 200" is inserted into the sheath 226. Once a seal is formed between the sheath 226 and the guide 230, fluid is introduced into the uterus 254 for distention. While optically and/or ultrasonically viewing the uterus 254 with the fiber optic scope 222 and/or the ultrasonic transducer 220, current is delivered to the electrosurgical wire 202 and the wire 202 is translated along the lining of the uterus 254 as indicated by arrow 256. Alternatively, before commencing a cut, ?.he ultrasonic transducer 220 can be actuated to survey and map the thickness of the uterus in the desired treatment area. The wire 202 is translated by sliding the device 200" within the sheath 226. As the wire 202 is translated, strips of tissue are removed and directed to the chopping mechanism 206 by the end wire 250 and shell 252. The removed strips of tissue are then chopped into smaller morsels by the chopping mechanism 206 as previously described. After the completion of the first cut, the surgeon directs the electrosurgical wire 202 to an adjacent area and draws the wire through the fibroid. With the completion of each cut, the wire 202 is repositioned and another cut is begun. The amount of material removed is controlled by the manually maneuvering, e.g., lifting or pivoting, the device 200" to adjust the depth of penetration of the wire 202 into the uterus and by the length of the cutting stroke.

In this way, strips of removed tissue are automatically directed into the chopping mechanism 206 for removal from the uterus. This reduces the time and effort normally incurred in removing shavings which block the field of view of the surgeon. Further, since the device does not need to be withdrawn from the uterus 254 to remove the shavings, the task of reorienting the device 200" is eliminated. Fatigue is also reduced which allows the surgeon to perform more precise work.

As described above, the resection devices and methods of the present invention generally allow removal and evacuation of uterine tissue by applying electrical current at relatively high voltage settings through a surgical instrument. The heat generated from the resistance of tissue to the flow of electrical current "vaporizes" the adjacent cells and also cauterizes small blood vessels. The present invention further provides tissue removal methods and devices which promote vaporization of a substantial portion of the target tissue to be removed, preferably vaporizing the majority of the target tissue, and in some cases vaporizing substantially the entire target tissue. In tissue vaporization, the heat from the electrocautery current causes intracellular water to boil, exploding the cells and causing the tissue to apparently melt away. However, a good deal of fine solid debris is created during vaporization, and tissue fragments of various sizes may also be severed and released. This solid debris would significantly degrade the image quality if allowed to accumulate at the surgical site, as described above. Hence, the aspiration of the debris of all forms, simultaneously with the removal of the tissue, substantially improves the quality of the image of the tissue removal procedure which is available, regardless of the relative amount of tissue which is vaporized relative to the amount which is released as strips, morsels, or fragments. For the above reasons, the embodiments of the present invention which emphasize tissue vaporization have structures and methods of use which are similar to those described above. As seen in Fig. 8, a tissue removal probe 310 generally has a proximal end 312 and a distal end 314. A probe shaft 316 supports a vaporizing member 318 near its distal end, the vaporizing member here including a plurality of rolling elements .319. Imaging scope 320 is distally oriented toward vaporizing member 318, and runs proximally within sheath 322. A probe handle housing 324 includes an actuation handle 326 for axially translating the shaft and vaporizing member relative to the sheath. An irrigation fluid port 328 and aspiration port 330 provide a continuous flow path for a clear, non-conductive fluid such as sorbitol-mannitol, mannitol, glycine, or the like. Alternatively, a conductive fluid might be used, as more fully described in U.S. Patent Application Serial No. 08/678,412, filed July 2, 1996, the full disclosure of which is incorporated herein by reference. Aspiration flow is controlled by an aspiration valve 332, so that the distension pressure may be maintained independently from flow. Electrosurgical connector wires 334 and a flex drive input 336 provide external electrical and mechanical power, minimizing the weight of housing 324. An optical image eyepiece 338 is removably attached to housing 324 to optically direct the tissue removal procedure. Optionally, an ultrasound transceiver may be mounted on the distal end of the probe. Such a distal ultrasound transducer may optionally comprise a one- or two-dimensional phased array to allow scanning of the tissue independent of any mechanical movement of the transducer probe.

Referring now to Fig. 9, a tissue removal system 340 utilizes the input and output connectors on the housing of probe 310, together with standard stand-alone surgical system components, to minimize cost, weight, and fatigue when using probe 310 in a tissue removal procedure. An irrigation supply 341 is connected to irrigation port 328 to provide a continuous flow of irrigation fluid during tissue removal. Preferably, irrigation supply 341 comprises a standard irrigation supply bag suspended above the surgical site to provide a constant pressure gravity feed, allowing distension pressure to be varied simply by changing the height of the irrigation supply. Alternatively, a valve or controlled flow pump may be used to supply irrigation fluid.

In the exemplary embodiment, aspiration, mechanical rotation, and electrosurgical potential are coupled to the shaft through a disposable cartridge 325 on shaft housing 324, the disposable cartridge reciprocating with the shaft as shown. This disposable cartridge structure facilitates replacement of the vaporizing member/shaft assembly (including the inner and outer tubes of the chopping mechanism or "morcellator") which would otherwise limit probe life. Fluid which leaves aspiration port 330 is directed through a filter canister 342 and then to an aspiration sump 344. Filter 342 removes the solid tissue fragments from the aspiration fluid for analysis. Sump 344 is preferably connected to a standard vacuum supply line to promote the withdrawal of aspiration fluid through the probe. Aspiration vacuum control is conveniently provided by aspiration valve 332 (see Fig. 8) .

Mechanical power is supplied to flex drive input 336 by drive motor 348. Drive motor 348 preferably rotates at least in the range between 500 and 1500 rpm, and typically allows for rotation in either direction, or oscillating rotation back and forth. The morcellator generally shears tissue mechanically, without requiring electrosurgical potential. The morcellator is a preferred feature, to promote aspiration of larger tissue fragments without clogging, but may not be required where the tissue is substantially entirely vaporized, or where tissue fragment size is limited by the shape of the rolling element of the vaporizing member, the electrosurgical power supplied, the relative motion of the rolling elements against the target tissue, and the like.

Controlled electrosurgical power is supplied through electrosurgical wires 334 to the vaporizing member by power unit 346. A switch (not shown) optionally allows application of electrosurgical power to be directed to an ablation roller mounted distally of the aperture (not shown) . Typically, electrosurgical power levels of between about 100 and 250 watts will be provided to effect tissue vaporization. The irrigation and aspiration flow paths, together with the optical viewing scope, are more fully described in co-pending U.S. Patent Application Serial No. 08/542,289, the full disclosure of which is herein incorporated by reference.

Referring to Fig. 10, an exemplary method for using tissue removal probe 310 typically comprises transcervically introducing sheath 322 into the uterus U. Such insertion is facilitated by use of an obturator, as described above. Manipulation of the probe is facilitated by limiting the sheath to a maximum of about 27 Fr (about 9 mm in diameter) . Once the sheath is properly positioned, the obturator is removed and the shaft 316, vaporizing member 318, and the scope 320 are inserted through the shaft and proximal housing 324 is attached to sheath coupling 350.

The probe is manipulated from the proximal housing 324 using articulation handle 326. The surgeon inserts the fingers of one hand througn finger handle 370, and inserts the thumb of the same hand through thumb ring 372. Preferably, the fingers are held stationary while the thumb ring extends the shaft and cutting member distally from the sheath. Thumn ring 372 is biased toward the proximal direction, so that removal of strips of tissue typically takes place under the assistance of biasing spring 373.

Removal of fibroid tissue from the uterus U begins with the vaporizing member 318 extended distally from the sheath 322 and energized with electrocautery potential , as described above. As illustrated in Fig. 10, the shaft is generally aligned with the tissue to be removed so that proximally actuating thumb ring 372 draws vaporizing member 318 through fibroid and/or endometrial tissue. The procedure is directed using scope 320, preferably while the scope and sheath are held substantially motionless using finger handle 370. Performing each cut towards the viewing scope helps to avoid inadvertently perforating uterus U.

In an alternative embodiment of the method of the present invention, the surgeon may manipulate the thumb ring relative to the finger handle to bring vaporizing member 318 to a preferred viewing distance from scope 320, and then translate the shaft and housing assemblies together proximally. This provides a longer cutting stroke for vaporizing member 318, and decreases the time required for the tissue removal procedure.

As vaporizing member 318 moves proximally, rolling elements 319 distribute the electrosurgical potential over a greater frontal area than wire 321 otherwise would alone. The disks generally have outward radial edges which concentrate the radio frequency at discrete intervals along the frontal area, and the disks will generally roll against (and thereby maintain continuous contact with) unvaporized fibroid or endometrial tissue to enhance vaporization. The edges of the rolling elements are within a predetermined separation distance, ideally being fanned outward radially along the arched wire. Optionally, most or substantially all of the adjacent tissue will be vaporized. Vaporization of substantially the entire removed tissue can generally be provided by electrical current at voltage settings of between about 1,000 and 9,000 volts, typically with an alternating current of between about 500 and 1,000 KHz. Alternatively, slightly lower electrosurgical potential, a greater separation between rollers, or <?n increase in cut depth allows discrete tissue fragments to be severed from the uterus by the vaporization of adjacent tissues. Generally, fragmentation will occur with deeper, more aggressive cuts in which roughly similar power settings are used. The predetermined separation distance between rollers generally helps to limit the width of released tissue fragments. Such limited-width tissue fragments are significantly easier to draw into the morcellator for extraction.

Regardless of whether tissue is removed primarily by vaporization or by fragmentation combined with vaporization, the cutting member will preferably have an increased frontal or axial projection area, and can therefore remove a greater volume of tissue with each stroke without overwhelming the morcellator when compared to a cutting wire. In fact, where substantially all the removed tissue is vaporized, no morcellator may be required to evacuate the remaining debris, although the morcellator is generally preferred to avoid clogging. Those of skill in the art will appreciate that such methods and devices will have many advantageous applications, including for the removal of selected thoracic tissues, particularly lung tissue, tissues of the bladder, and tissues of the prostate.

Referring now to Figs. 11 and 12, the orientation and flow of aspiration flow path 380 over scope 320 is illustrated. The interaction of shaving port 356 on chopping tube 358 with aperture 354 of shaft 316 is also clearly seen. In the exemplary embodiment, cutting member 318 includes an energized wire 321 having proximal ends disposed within and electrically insulated from support insulated tubes 381 which are soldered to shaft 316, the tubes and shaft being insulated with shrink-wrap tubing 382. As shown most clearly in the simplified end view of Fig. 12, wire 321 forms a transverse arch along which the rolling elements 319 are disposed. Insulation 383 between wire 321 and tubes 381 is also shown.. Preferably, the entire cutting member 318, including wire 321 and rolling elements 319, is smaller than the lumen of sheath 322 to facilitate insertion and removal of the cutting member/shaft assembly.

Referring now to Figs. 13A and B, rolling element 319 optionally comprises a simple disk with a central passage 390 for the wire. The rolling element generally comprises an electrically conductive material which will withstand the temperatures created in the ablation process, preferably comprising brass, stainless steel, plated steel, or plated stainless steel.

Referring to Figs. 14-14B, a plurality of spurred rolling elements 392 optionally directly replace the plurality of disks in cutting member 318 (see Figs. 11 and 12) . Each spurred rolling element includes a plurality of radially protruding elements 394 which enhance tissue/rolling element friction to promote rolling, and which also further direct vaporizing energy into the fibroid tissue, thereby increasing the volume of tissue removed with each pass. Optionally, the electrosurgical potential applied through such a spurred rolling element may promote removal of tissue through increased vaporization depth, and may also enhance fragmentation and severing of the adjacent unvaporized tissue, increasing the efficiency of tissue removal.

Optionally, a plurality of spurred rolling elements may be fanned outward along a curved wire, as described above. Alternatively, a single spurred cylinder 396 supported on a straight, transverse energized wire could span the ablation area as a single roller to produce a square cut. In a still further alternative, a spurred sphere 398 mounted on a similar straight energized wire will create an arched cut.

Although the foregoing invention has been described in detail by way of illustration and example, for purposes of clarity of understanding, it will be obvious that certain changes and modification may be practiced in the scope of the appended claims.

Claims

WHAT IS CLAIMED IS;

1. A method for extracting tissue from the uterus, the method comprising: removing tissue from the uterus by applying radio frequency electrical power to the tissue so that a portion of the removed tissue is vaporized; viewing depth of tissue removed from the uterus while removing the tissue; and evacuating tissue removed from the uterus while removing the tissue.

2. A method as claimed in claim 1, wherein the removing step comprises applying the radio frequency with an electrosurgical element of a probe, wherein the viewing step comprises optically imaging with a scope of the probe, and wherein the evacuating step comprises aspirating the removed tissue through an aspiration lumen of the probe.

3. A method as claimed in claim 2, wherein irrigation fluid flows from adjacent the scope toward the electrosurgical element.

4. A method as claimed in claim 3, wherein the aspirating step maintains image clarity by drawing removed tissue from adjacent the electrosurgical element away from the scope.

5. A method as claimed in claim 1, wherein the removing step comprises translating a member through uterine tissue while the member is energized with the radio frequency power to vaporize tissue adjacent the member.

6. A method as claimed in claim 5, wherein the translating step severs unvaporized tissue from the uterus.

7. A method as claimed in claim 6 , wher .n the evacuating step comprises morcellatmg the severed tissue within the uterus and aspirating the morcellated tissue and the vaporized tissue.

8. A method as claimed in claim 7, wherein the majority of removed tissue is vaporized, and wherein the morcellatmg step avoids clogging of an aspiration lumen.

9. A method as claimed in claim 5, wherein the removing step comprises vaporizing substantially the entire removed tissue.

10. A method as claimed in claim 5, wherein the translating step comprises passing at least one rollable element through the uterine tissue, the member comprising a rollable element.

11. A method as claimed in claim 10, wherein the removing step further comprises directing energy into the uterine tissue with a plurality of spurs on the at least one rollable element.

12. A method as claimed in claim 10, wherein the removing step further comprises directing energy into the uterine tissue with a plurality of rollable elements disposed along an arched wire.

13. An electrosurgical device comprising: a shaft having a proximal end, a distal end, an aperture near the distal end, and an aspiration lumen between the aperture and the proximal end; an electrosurgical member disposed near the aperture which vaporizes tissue from an internal surgical site when the member is energized and translated through a target tissue; and an imaging mechanism disposed along the shaft and oriented toward the member so as to view the target tissue, wherein debris aspirated toward the aperture from adjacent the electrosurgical member, moves away from the imaging mechanism so as to maintain image quality.

14. An electrosurgical device as claimed in claim 13, wherein the member comprises a cutting wire to sever tissue adjacent the vaporized tissue from the surgical site.

15. An electrosurgical device as claimed in claim 14, further comprising a morcellator disposed adjacent the aperture to chop the severed tissue into fragments.

16. An electrosurgical device as claimed in claim 13, wherein the electrosurgical member comprises a rolling element .

17. An electrosurgical device as claimed in claim 16, wherein the rolling element directs energy into the target tissue so as to fragment tissue adjacent the vaporized tissue.

18. An electrosurgical device as claimed in claim 16, wherein the rolling element comprises a plurality of spurs which direct the energy into the target tissue.

19. An electrosurgical device as claimed in claim 16, wherein the electrosurgical member further comprises a plurality of rolling elements disposed on a curved wire.

20. An electrosurgical device as claimed in claim 18, wherein the rolling elements comprise disks, and wherein the curve comprises an arch so that the disks fan outward.

21. An electrosurgical device as claimed in claim 13, further comprising a sheath having an infusion lumen disposed along the shaft, the infusion lumen having a fluid outlet proximally of the electrosurgical member, wherein the imaging mechanism is disposed adjacent to the fluid outlet and oriented distally toward the electrosurgical member, and wherein the aperture is disposed distally of the electrosurgical member so that image clarity is maintained when the electrosurgical device is translated proximally.