Patent Description:
Uterine fibroids arc non-cancerous tumors that develop in the wall of uterus. Such fibroids occur in a large percentage of the female population, with some studies indicating that up to <NUM> percent of all women have fibroids. Uterine fibroids can grow over time to be several centimeters in diameter and symptoms can include menorrhagia, reproductive dysfunction, pelvic pressure and pain.

One current treatment of fibroids is hysteroscopic resection or myomec-tomy which involves transcervical access to the uterus with a hysteroscope together with insertion of a cutting instrument through a working channel in the hysteroscope. The cutting instrument may be a mechanical tissue cutter or an electro surgical resection device such as a cutting loop. Mechanical cutting devices are disclosed in <CIT>; <CIT> and <CIT> and <CIT>. An electrosurgical cutting device is disclosed in <CIT>.

While hysteroscopic resection can be effective in removing uterine fibroids, many commercially available instrument arc too large in diameter and thus require anesthesia in an operating room environment. Conventional resectoscopes require cervical dilation to about <NUM>. What is needed is a system that can effectively cut and remove fibroid tissue through a small diameter hysteroscope.

<CIT> relates to a cutting system including a cutter which has an inner sleeve that moves adjacent to an aspiration port of an outer sleeve. The inner sleeve is coupled to a source of vacuum that pulls tissue into the outer port when the inner sleeve is moved away from the port. The inner sleeve then moves across the outer port and severs the tissue in a guillotine fashion. The tip of the inner sleeve may exert a spring force that assist in the cutting action of the cutter. The cutter includes a motor which creates an oscillating translational movement of the sleeve. The inner sleeve is coupled to an aspiration line that pulls the severed tissue out of the cutter.

The present invention is defined by the appened claims.

<FIG> illustrates an assembly that comprises an endoscope <NUM> used for hysteroscopy together with a tissue-extraction device <NUM> extending through a working channel <NUM> of the endoscope. The endoscope or hysteroscope <NUM> has a handle <NUM> coupled to an elongated shaft <NUM> having a diameter of <NUM> to <NUM>. The working channel <NUM> therein may be round, D-shaped or any other suitable shape. The endoscope shaft <NUM> is further configured with an optics channel <NUM> and one or more fluid inflow/outflow channels 108a, 108b (<FIG>) that communicate with valve-connectors 110a, 110b configured for coupling to a fluid inflow source <NUM> thereto, or optionally a negative pressure source <NUM> (<FIG>). The fluid inflow source <NUM> is a component of a fluid management system <NUM> as is known in the art (<FIG>) which comprises a fluid container <NUM> and pump mechanism <NUM> which pumps fluid through the hysteroscope <NUM> into the uterine cavity. As can be seen in <FIG>, the fluid management system <NUM> further includes the negative pressure source <NUM> (which can comprise an operating room wall suction source) coupled to the tissue-cutting device <NUM>. The handle <NUM> of the endoscope includes the angled extension portion <NUM> with optics to which a videoscopic camera <NUM> can be operatively coupled. A light source <NUM> also is coupled to light coupling <NUM> on the handle of the hysteroscope <NUM>. The working channel <NUM> of the hysteroscope is configured for insertion and manipulation of the tissue-cutting and extracting device <NUM>, for example to treat and remove fibroid tissue. In one embodiment, the hysteroscope shaft <NUM> has an axial length of <NUM>, and can comprise a <NUM>° scope, or <NUM>° to <NUM>° scope.

Still referring to <FIG>, the tissue-cutting device <NUM> has a highly elongated shaft assembly <NUM> configured to extend through the working channel <NUM> in the hysteroscope. A handle <NUM> of the tissue-cutting device <NUM> is adapted for manipulating the electrosurgical working end <NUM> of the device. In use, the handle <NUM> can be manipulated both rotationally and axially, for example, to orient the working end <NUM> to cut targeted fibroid tissue. The tissue-cutting device <NUM> has subsystems coupled to its handle <NUM> to enable electrosurgical cutting of targeted tissue. A radio frequency generator or RF source <NUM> and controller <NUM> are coupled to at least one RF electrode carried by the working end <NUM> as will be described in detail below. In one embodiment shown in <FIG>, an electrical cable <NUM> and negative pressure source <NUM> are operatively coupled to a connector <NUM> in handle <NUM>. The electrical cable couples the RF source <NUM> to the electrosurgical working end <NUM>. The negative pressure source <NUM> communicates with a tissue-extraction channel <NUM> in the shaft assembly <NUM> of the tissue extraction device <NUM> (<FIG>).

<FIG> further illustrates a seal housing <NUM> that carries a flexible seal <NUM> carried by the hysteroscope handle <NUM> for sealing the shaft <NUM> of the tissue-cutting device <NUM> in the working channel <NUM> to prevent distending fluid from escaping from a uterine cavity.

In one embodiment as shown in <FIG>, the handle <NUM> of tissue-cutting device <NUM> includes a motor drive <NUM> for reciprocating or otherwise moving a cutting component of the electrosurgical working end <NUM> as will be described below. The handle <NUM> optionally includes one or more actuator buttons <NUM> for actuating the device. In another embodiment, a footswitch can be used to operate the device. In one embodiment, the system includes a switch or control mechanism to provide a plurality of reciprocation speeds, for example <NUM>, <NUM>, <NUM>, <NUM> and up to <NUM>. Further, the system can include a mechanism for moving and locking the reciprocating cutting sleeve in a non-extended position and in an extended position. Further, the system can include a mechanism for actuating a single reciprocating stroke.

Referring to <FIG> and <FIG>, an electrosurgical tissue-cutting device has an elongate shaft assembly <NUM> extending about longitudinal axis <NUM> comprising an exterior or first outer sleeve <NUM> with passageway or lumen <NUM> therein that accommodates a second or inner sleeve <NUM> that can reciprocate (and optionally rotate or oscillate) in lumen <NUM> to cut tissue as is known in that art of such tubular cutters. In one embodiment, the tissue-receiving window <NUM> in the outer sleeve <NUM> has an axial length ranging between <NUM> and <NUM> and extends in a radial angle about outer sleeve <NUM> from about <NUM>° to <NUM>° relative to axis <NUM> of the sleeve. The outer and inner sleeves <NUM> and <NUM> can comprise a thin-wall stainless steel material and function as opposing polarity electrodes as will be described in detail below. <FIG> illustrate insulative layers carried by the outer and inner sleeves <NUM> and <NUM> to limits, control and/or prevent unwanted electrical current flows between certain portions go the sleeve. In one embodiment, a stainless steel outer sleeve <NUM> has an O. of <NUM>" with an I. of <NUM>" and with an inner insulative layer (described below) the sleeve has a nominal I. In this embodiment, the stainless steel inner sleeve <NUM> has an O. <NUM>" with an I. The inner sleeve <NUM> with an outer insulative layer has a nominal O. of about <NUM>" to <NUM>" to reciprocate in lumen <NUM>. In other embodiments, outer and or inner sleeves can be fabricated of metal, plastic, ceramic of a combination thereof The cross-section of the sleeves can be round, oval or any other suitable shape.

As can be seen in <FIG>, the distal end <NUM> of inner sleeve <NUM> comprises a first polarity electrode with distal cutting electrode edge <NUM> about which plasma can be generated. The electrode edge <NUM> also can be described as an active electrode during tissue cutting since the electrode edge <NUM> then has a substantially smaller surface area than the opposing polarity or return electrode. In one embodiment in <FIG>, the exposed surfaces of outer sleeve <NUM> comprises the second polarity electrode <NUM>, which thus can be described as the return electrode since during use such an electrode surface has a substantially larger surface area compared to the functionally exposed surface area of the active electrode edge <NUM>.

In one aspect the inner sleeve or cutting sleeve <NUM> has an interior tissue extraction lumen <NUM> with first and second interior diameters that are adapted to electrosurgically cut tissue volumes rapidly-and thereafter consistently extract the cut tissue strips through the highly elongated lumen <NUM> without clogging. Now referring to <FIG> and <FIG>, it can be seen that the inner sleeve <NUM> has a first diameter portion 190A that extends from the handle <NUM> (<FIG>) to a distal region <NUM> of the sleeve <NUM> wherein the tissue extraction lumen transitions to a smaller second diameter lumen 190B with a reduced diameter indicated at B which is defined by the electrode sleeve element <NUM> that provides cutting electrode edge <NUM>. The axial length C of the reduced cross-section lumen 190B can range from about <NUM> to <NUM>. In one embodiment, the first diameter A is <NUM>" and the second reduced diameter B is <NUM>". As shown in <FIG>, the inner sleeve <NUM> can be an electrically conductive stainless steel and the reduced diameter electrode portion also can comprise a stainless steel electrode sleeve element <NUM> that is welded in place by weld <NUM> (<FIG>). In another alternative embodiment, the electrode and reduced diameter electrode sleeve element <NUM> comprises a tungsten tube that can be press fit into the distal end <NUM> of inner sleeve <NUM>. <FIG> and <FIG> further illustrates the interfacing insulation layers <NUM> and <NUM> carried by the first and second sleeves <NUM>, <NUM>, respectively. In <FIG>, the outer sleeve <NUM> is lined with a thin-wall insulative material <NUM>, such as PFA, or another material described below. Similarly, the inner sleeve <NUM> has an exterior insulative layer <NUM>. These coating materials can be lubricious as well as electrically insulative to reduce friction during reciprocation of the inner sleeve <NUM>.

The insulative layers <NUM> and <NUM> described above can comprise a lubricious, hydrophobic or hydrophilic polymeric material. For example, the material can comprise a biocompatible material such as PFA, TEFLON®, polytetrafluroethylene (PTFE), FEP (Fluorinated ethylenepropylene), polyethylene, polyamide, ECTFE (Ethylenechlorotrifluoro-ethylene), ETFE, PVDF, polyvinyl chloride or silicone.

Now turning to <FIG>, another variation of inner sleeve <NUM> is illustrated in a schematic view together with a tissue volume being resected with the plasma electrode edge <NUM>. In this embodiment, as in other embodiments in this disclosure, the RF source operates at selected operational parameters to create a plasma around the electrode edge <NUM> of electrode sleeve <NUM> as is known in the art. Thus, the plasma generated at electrode edge <NUM> can cut and ablate a path P in the tissue <NUM>, and is suited for cutting fibroid tissue and other abnormal uterine tissue. In <FIG>, the distal portion of the cutting sleeve <NUM> includes a ceramic collar <NUM> which is adjacent the distal edge <NUM> of the electrode sleeve <NUM>. The ceramic <NUM> collar functions to confine plasma formation about the distal electrode edge <NUM> and functions further to prevent plasma from contacting and damaging the polymer insulative layer <NUM> on the cutting sleeve <NUM> during operation. In one aspect of the invention, the path P cut in the tissue <NUM> with the plasma at electrode edge <NUM> provides a path P having an ablated width indicated at W, wherein such path width W is substantially wide due to tissue vaporization. This removal and vaporization of tissue in path P is substantially different than the effect of cutting similar tissue with a sharp blade edge, as in various prior art devices. A sharp blade edge can divide tissue (without cauterization) but applies mechanical force to the tissue and may prevent a large cross section slug of tissue from being cut. In contrast, the plasma at the electrode edge <NUM> can vaporize a path P in tissue without applying any substantial force on the tissue to thus cut larger cross sections or slugs strips of tissue. Further, the plasma cutting effect reduces the cross section of tissue strip <NUM> received in the tissue-extraction lumen 190B. <FIG> depicts a tissue strip to <NUM> entering lumen 190B which has such a smaller cross-section than the lumen due to the vaporization of tissue. Further, the cross section of tissue <NUM> as it enters the larger cross-section lumen 190A results in even greater free space <NUM> around the tissue strip <NUM>. Thus, the resection of tissue with the plasma electrode edge <NUM>, together with the lumen transition from the smaller cross-section (190B) to the larger cross-section (190A) of the tissue-extraction lumen <NUM> can significantly reduce or eliminate the potential for successive resected tissue strips <NUM> to clog the lumen. Prior art resection devices with such small diameter tissue-extraction lumen typically have problems with tissue clogging.

In another aspect the negative pressure source <NUM> coupled to the proximal end of tissue-extraction lumen <NUM> (see <FIG> and <FIG>) also assists in aspirating and moving tissue strips <NUM> in the proximal direction to a collection reservoir (not shown) outside the handle <NUM> of the device.

<FIG> illustrate the change in lumen diameter of cutting sleeve <NUM> of <FIG>. <FIG> illustrates the distal end of a variation of cutting sleeve <NUM>' which is configured with an electrode cutting element <NUM>' that is partially tubular in contrast to the previously described tubular electrode element <NUM> (<FIG> and <FIG>). <FIG> again illustrate the change in cross-section of the tissue- extraction lumen between reduced cross-section region 190B' and the increased cross-section region 190A' of the cutting sleeve <NUM>' of <FIG>. Thus, the functionality remains the same whether the cutting electrode element <NUM>' is tubular or partly tubular. 8A, the ceramic collar <NUM>' is shown, in one variation, as extending only partially around sleeve <NUM> to cooperate with the radial angle of cutting electrode element <NUM>'. Further, the variation of <FIG> illustrates that the ceramic collar <NUM>' has a larger outside diameter than insulative layer <NUM>. Thus, friction may be reduced since the short axial length of the ceramic collar <NUM>' interfaces and slides against the interfacing insulative layer <NUM> about the inner surface of lumen <NUM> of outer sleeve <NUM>.

In general, one aspect comprises a tissue cutting and extracting device (<FIG>) that includes first and second concentric sleeves having an axis and wherein the second (inner) sleeve <NUM> has an axially-extending tissue-extraction lumen therein, and wherein the second sleeve <NUM> is moveable between axially non-extended and extended positions relative to a tissue-receiving window <NUM> in first sleeve <NUM> to resect tissue, and wherein the tissue extraction lumen <NUM> has first and second cross-sections. The second sleeve <NUM> has a distal end configured as a plasma electrode edge <NUM> to resect tissue disposed in tissue-receiving window <NUM> of the first sleeve <NUM>. Further, the distal end of the second sleeve, and more particularly, the electrode edge <NUM> is configured for plasma ablation of a substantially wide path in the tissue. In general, the tissue-extraction device is configured with a tissue extraction lumen <NUM> having a distal end portion with a reduced cross-section that is smaller than a cross-section of medial and proximal portions of the lumen <NUM>.

In one aspect of the invention, referring to <FIG> and <FIG>, the tissue-extraction lumen <NUM> has a reduced cross-sectional area in lumen region 190A proximate the plasma cutting tip or electrode edge <NUM> wherein said reduced cross section is less that <NUM>%, <NUM>%, <NUM>% or <NUM>% than the cross sectional area of medial and proximal portions 190B of the tissue-extraction lumen, and wherein the axial length of the tissue-extraction lumen is at least <NUM>, <NUM>, <NUM> or <NUM>. In one embodiment of tissue-cutting device <NUM> for hysteroscopic fibroid cutting and extraction (<FIG>), the shaft assembly <NUM> of the tissue-cutting device is <NUM> in length.

<FIG> illustrate the working end <NUM> of the tissue-cutting device <NUM> with the reciprocating cutting sleeve or inner sleeve <NUM> in three different axial positions relative to the tissue receiving window <NUM> in outer sleeve <NUM>. In <FIG>, the cutting sleeve <NUM> is shown in a retracted or non-extended position in which the sleeve <NUM> is at it proximal limit of motion and is prepared to advance distally to an extended position to thereby electrosurgically cut tissue positioned in and/or suctioned into in window <NUM>. <FIG> shows the cutting sleeve <NUM> moved and advanced distally to a partially advanced or medial position relative to tissue cutting window <NUM>. <FIG> illustrates the cutting sleeve <NUM> fully advanced and extended to the distal limit of its motion wherein the plasma cutting electrode <NUM> has extended past the distal end <NUM> of tissue-receiving window <NUM> at which moment the resected tissue strip <NUM> in excised from tissue volume <NUM> and captured in reduced cross-sectional lumen region 190A.

Now referring to <FIG>, <FIG> and <FIG>, another aspect comprises "tissue displacement" mechanisms provided by multiple elements and processes to "displace" and move tissue strips <NUM> (<FIG>) in the proximal direction in lumen <NUM> of cutting sleeve <NUM> to thus ensure that tissue does not clog the lumen of the inner sleeve <NUM>. As can seen in <FIG> and the enlarged views of <FIG>, one tissue displacement mechanism comprises a projecting element <NUM> that extends proximally from distal tip <NUM> which is fixedly attached to outer sleeve <NUM>. The projecting element <NUM> extends proximally along central axis <NUM> in a distal chamber <NUM> defined by outer sleeve <NUM> and distal tip <NUM>. In one embodiment depicted in <FIG>, the shaft-like projecting element <NUM>, in a first functional aspect, comprises a mechanical pusher that functions to push a captured tissue strip <NUM> proximally from the small cross-section lumen 190B of cutting sleeve <NUM> (<FIG>) as the cutting sleeve <NUM> moves to its fully advanced or extended position.

In a second functional aspect, the chamber <NUM> in the distal end of sleeve <NUM> is configured to capture a volume of saline distending fluid <NUM> (<FIG>) from the working space, and wherein the existing RF electrodes of the working end <NUM> are further configured to explosively vaporize the captured fluid <NUM> to generate proximally-directed forces on tissue strips <NUM> resected and disposed in lumen <NUM> of the cutting sleeve <NUM> (<FIG> and <FIG>). Both of these functional elements and processes (tissue displacement mechanisms) can apply a substantial mechanical force on the captured tissue strips <NUM> by means of the explosive vaporization of liquid in chamber <NUM> and can function to move tissue strips <NUM> in the proximal direction in the tissue-extraction lumen <NUM>. It has been found that using the combination of multiple functional elements and processes can virtually eliminate the potential for tissue clogging the tissue extraction lumen <NUM>.

More particularly, <FIG> illustrate the functional aspects of the tissue displacement mechanisms and the subsequent explosive vaporization of fluid captured in chamber <NUM>. In <FIG>, the reciprocating cutting sleeve <NUM> is shown in a medial position advancing distally wherein plasma at the cutting electrode edge <NUM> is cutting a tissue strip <NUM> that is disposed within lumen <NUM> of the cutting sleeve <NUM>. In <FIG>, it can be seen that the system operates in first and second electrosurgical modes corresponding to the reciprocation and axial range of motion of cutting sleeve <NUM> relative to the tissue-receiving window <NUM>. As used herein, the term "electrosurgical mode" refers to which electrode of the two opposing polarity electrodes functions as an "active electrode" and which electrode functions as a "return electrode". The terms "active electrode" and "return electrode" are used in accordance with convention in the art-wherein an active electrode has a smaller surface area than the return electrode which thus focuses RF energy density about such an active electrode. In the working end <NUM> of <FIG>, the cutting electrode element <NUM> and its cutting electrode edge <NUM> must comprise the active electrode to focus energy about the electrode to generate the plasma for tissue cutting. Such a high-intensity, energetic plasma at the electrode edge <NUM> is needed throughout stroke X indicated in <FIG> to cut tissue. The first mode occurs over an axial length of travel of inner cutting sleeve <NUM> as it crosses the tissue-receiving window <NUM>, at which time the entire exterior surface of outer sleeve <NUM> comprises the return electrode indicated at <NUM>. The electrical fields EF of the first RF mode are indicated generally in <FIG>.

<FIG> illustrates the moment in time at which the distal advancement or extension of inner cutting sleeve <NUM> entirely crosses the tissue-receiving window <NUM> (<FIG>). At this time, the electrode sleeve <NUM> and its electrode edge <NUM> are confined within the mostly insulated-wall chamber <NUM> defined by the outer sleeve <NUM> and distal tip <NUM>. At this moment, the system is configured to switch to the second RF mode in which the electric fields EF switch from those described previously in the first RF mode. As can be seen in <FIG>, in this second mode, the limited interior surface area <NUM> (<FIG>) of distal tip <NUM> that interfaces chamber <NUM> functions as an active electrode and the distal end portion of cutting sleeve <NUM> exposed to chamber <NUM> acts as a return electrode. In this mode, very high energy densities occur about surface <NUM> and such a contained electric field EF can explosively and instantly vaporize the fluid <NUM> captured in chamber <NUM>. The expansion of water vapor can be dramatic and can thus apply tremendous mechanical forces and fluid pressure on the tissue strip <NUM> to move the tissue strip in the proximal direction in the tissue extraction lumen <NUM>. <FIG> illustrates such explosive or expansive vaporization of the distention fluid <NUM> captured in chamber <NUM> and further shows the tissue strip <NUM> being expelled in the proximal direction the lumen <NUM> of inner cutting sleeve <NUM>.

<FIG> shows the relative surface areas of the active and return electrodes at the extended range of motion of the cutting sleeve <NUM>, again illustrating that the surface area of the non-insulated distal end surface <NUM> is small compared to surface <NUM> of electrode sleeve which comprises the return electrode.

Still referring to <FIG>, it has been found that a single power setting on the RF source <NUM> and controller <NUM> can be configured both (i) to create plasma at the electrode cutting edge <NUM> of electrode sleeve <NUM> to cut tissue in the first mode, and (ii) to explosively vaporize the captured distention fluid <NUM> in the second mode. Further, it has been found that the system can function with RF mode-switching automatically at suitable reciprocation rates ranging from <NUM> cycles per second to <NUM> or <NUM> cycles per second. In bench testing, it has been found that the tissue-cutting device described above can cut and extract tissue at the rate of from <NUM> grams/min to <NUM> grams/min without any potential for tissue strips <NUM> clogging the tissue-extraction lumen <NUM>. In these embodiments, the negative pressure source <NUM> also is coupled to the tissue-extraction lumen <NUM> to assist in applying forces for tissue extraction.

Of particular interest, the fluid-capture chamber <NUM> defined by sleeve <NUM> and distal tip <NUM> can be designed to have a selected volume, exposed electrode surface area, length and geometry to optimize the application of expelling forces to resected tissue strips <NUM>. In one embodiment, the diameter of the chamber is <NUM> and the length is <NUM> which taking into account the projecting element <NUM>, provided a captured fluid volume of approximately <NUM>. In other variations, the captured fluid volume can range from <NUM> to <NUM>.

In one example, a chamber <NUM> with a captured liquid volume of <NUM> together with <NUM>% conversion efficiency in and instantaneous vaporization would require <NUM> Joules to heat the liquid from room temperature to water vapor. In operation, since a Joule is a W*s, and the system reciprocate at <NUM>, the power required would be on the order of <NUM> W for full, instantaneous conversion to water vapor. A corresponding theoretical expansion of 1700x would occur in the phase transition, which would results in up to <NUM>,<NUM> psi instantaneously (<NUM>. 7psi x <NUM>), although due to losses in efficiency and non-instantaneous expansion, the actual pressures would be much less. In any event, the pressures are substantial and can apply significant expelling forces to the captured tissue strips <NUM>.

Referring to <FIG>, the interior chamber <NUM> can have an axial length from about <NUM> to <NUM> to capture a liquid volume ranging from about <NUM> <NUM>. It can be understood in <FIG>, that the interior wall of chamber <NUM> has an insulator layer <NUM> which thus limits the electrode surface area <NUM> exposed to chamber <NUM>. In one embodiment, the distal tip <NUM> is stainless steel and is welded to outer sleeve <NUM>. The post element <NUM> is welded to tip <NUM> or machined as a feature thereof. The projecting element <NUM> in this embodiment is a non-conductive ceramic.

<FIG> shows the cross-section of the ceramic projecting element <NUM> which may be fluted, and which in one embodiment has three flute elements <NUM> and three corresponding axial grooves <NUM> in its surface. Any number of flutes, channels or the like is possible, for example from two to about <NUM>. The fluted design increases the available cross-sectional area at the proximal end of the projecting element <NUM> to push the tissue strip <NUM>, while at the same time the three grooves <NUM> permit the proximally-directed jetting of water vapor to impact the tissue exposed to the grooves <NUM>. In one embodiment, the axial length D (<FIG>) of the projecting element <NUM> is configured to push tissue entirely out of the reduced cross-sectional region 190B of the electrode sleeve element <NUM>. In another embodiment, the volume of the chamber <NUM> is configured to capture liquid that when explosively vaporized provided a gas (water vapor) volume sufficient to expand into and occupy at least the volume defined by a <NUM>% of the total length of extraction channel <NUM> in the device, usually at least <NUM>% of the extraction channel <NUM>, often at least <NUM>% of the extraction channel <NUM>, sometimes at least <NUM>% of the extraction channel <NUM>, other times at least <NUM>% of the extraction channel <NUM>, and sometimes at least <NUM><NUM>% of the extraction channel <NUM>.

As can be understood from <FIG>, the distending fluid <NUM> in the working space replenishes the captured fluid in chamber <NUM> as the cutting sleeve <NUM> moves in the proximal direction or towards its non-extended position. Thus, when the cutting sleeve <NUM> again moves in the distal direction to cut tissue, the interior chamber <NUM> is filled with fluid <NUM> which is then again contained and is then available for explosive vaporization as described above when the cutting sleeve <NUM> closes the tissue-receiving window <NUM>. In another embodiment, a one-way valve can be provided in the distal tip <NUM> to draw fluid directly into interior chamber <NUM> without the need for fluid to migrate through window <NUM>.

<FIG> illustrates another variation in which the active electrode surface area <NUM>' in the second mode comprises a projecting element <NUM> with conductive regions and non-conductive regions <NUM> which can have the effect of distributing the focused RF energy delivery over a plurality of discrete regions each in contact with the captured fluid <NUM>. This configuration can more efficiently vaporize the captured fluid volume in chamber <NUM>. In one embodiment, the conductive regions <NUM>' can comprise metal discs or washers on post <NUM>. In other variation (not shown) the conductive regions <NUM>' can comprise holes, ports or pores in a ceramic material <NUM> fixed over an electrically conductive post <NUM>.

In another embodiment, the RF source <NUM> and controller <NUM> can be programmed to modulate energy delivery parameters during stroke X and stroke Y in <FIG> to provide the optimal energy (i) for plasma cutting with electrode edge <NUM>, and (ii) for explosively vaporizing the captured fluid in chamber <NUM>.

<FIG> illustrate another embodiment RF cutting probe <NUM> with working end <NUM> comprising a tubular cutter adapted for electrosurgical cutting and extracting targeted tissue from the interior of a patient's body. However, in this embodiment, the inner cutting sleeve is configured to rotate instead of reciprocate as in the previously-described embodiments.

Referring to <FIG>, the outer sleeve <NUM> comprises a metal tubular member <NUM> that extends from a handle (not shown) to a working end <NUM> that again carries a distal dielectric body <NUM> defining a window <NUM> therein. The inner second sleeve or cutting sleeve <NUM> comprises a metal tubular member <NUM> that carries a distal dielectric body <NUM> with a windowed side <NUM> that is adapted to cooperate with window <NUM> in the outer sleeve <NUM>.

<FIG> show the working end <NUM> of probe <NUM> with the rotating cutting sleeve <NUM> and RF electrode edge <NUM> in two different rotational positions with respect to outer sleeve <NUM> and window <NUM>. In <FIG>, the inner sleeve <NUM> is rotated approximately <NUM>° relative to the outer sleeve <NUM>. In <FIG>, the inner sleeve <NUM> is rotated <NUM>° to a position relative to inner sleeve <NUM> to effectively close the window <NUM> defined by the outer sleeve <NUM>. It can easily be understood how rotation of electrode edge <NUM> thus can cut tissue during rotation and capture the tissue in the window-closed position within the tissue-receiving lumen <NUM> of the probe.

In this embodiment of <FIG>, the RF electrode edge <NUM> of the inner sleeve <NUM> comprises a first polarity electrode. The exterior surface <NUM> of the outer sleeve <NUM> comprises a second polarity electrode as described in previous embodiments. As can be understood from <FIG>, it is critical that the first and second polarity electrode surfaces (<NUM> and <NUM>) are spaced apart by a predetermined dimension throughout the rotation of inner sleeve <NUM> relative to outer sleeve <NUM>. In one aspect the distal ends of the inner and outer sleeves comprise ceramic bodies <NUM> and <NUM> with an interface <NUM> therebetween. In other words, the ceramic bodies <NUM> and <NUM> rotate about interface <NUM> and the bodies provide exact electrode spacing ES between the first and second polarity electrodes <NUM> and <NUM>.

Now referring to <FIG>, it can be seen how the outer sleeve <NUM> comprises as an assembly between the tubular metal sleeve <NUM> and the dielectric body <NUM>, which in this variation can be a ceramic such as zirconium. In <FIG>, it can be seen that the ceramic body <NUM> has a thin wall <NUM> which can range in thickness from about <NUM>" and <NUM>" wherein the ceramic extends <NUM>° around window <NUM>. Ceramic body <NUM> can thus be slidably inserted into and bonded to bore <NUM> in metal sleeve <NUM>.

Now turning to <FIG>, the distal end of inner sleeve <NUM> is shown de-mated from the outer sleeve assembly <NUM> (see <FIG>). The tubular metal sleeve <NUM> of <FIG> is fabricated to allow insertion of the ceramic body <NUM> which supports the electrode edge <NUM> and provides a rotational bearing surface about the interface <NUM> (see <FIG>). <FIG> shows an exploded view of the inner sleeve assembly of <FIG>. In <FIG>, it can be seen that ceramic body <NUM> has a hemispherical cross-sectional shape and includes an elongated slots <NUM> for receiving and supporting an electrode edge <NUM>. <FIG> further shows metal sleeve <NUM> without ceramic body <NUM> wherein the electrode edge <NUM> is cut from a rounded end sleeve <NUM>. It can be understood that the slot <NUM> can receive ceramic body <NUM> and thus the electrode edge <NUM> extends in a loop and under rotation will have a leading edge <NUM> and a trailing edge <NUM>' depending on the direction of rotation. As used herein, the term 'leading edge' refers to the electrode edge <NUM> extending around the distal end of the sleeve <NUM> to its centerline on its rotational axis.

In one aspect the tissue cutting probe <NUM> comprises an outer sleeve <NUM> and an inner sleeve <NUM> that is rotatable to provide window-open and window-closed positions and wherein the distal ends of the first and second sleeves <NUM>, <NUM> include ceramic bodies <NUM>, <NUM> that provide surfaces on either side of a rotational interface <NUM>. Further, the first and second sleeves provide ceramic bodies <NUM>, <NUM> that contact one another on either side of the rotational interface <NUM> and thus provide a predetermined electrode spacing ES (<FIG>). In one variation, the wall thickness of the ceramic body <NUM> is from <NUM>" to <NUM>". Likewise, the wall thickness of ceramic body <NUM> can be from <NUM>" to <NUM>". Thus, the radial dimension between the first and second polarity electrodes at a minimum in this variation is <NUM>". In another variation in which the inner sleeve <NUM> carries an outer polymeric dielectric layer which can be <NUM>" in thickness to thus provide an electrode spacing dimension ES of <NUM>". In other variations having a larger diameter, the dimension between the first and second polarity electrodes can range up to <NUM>".

In the embodiment shown in <FIG>, the length of the window can range from about <NUM> to <NUM>. The diameter of the probe working end can range from about <NUM> to <NUM> or more. The rotational speed of the inner sleeve can range from <NUM> rpm to <NUM>,<NUM> rpm. In one embodiment, a rotation ranging from about <NUM> rpm to <NUM> rpm cut tissue efficiently and allowed for effective tissue extraction as described below.

In another aspect of the invention, referring to <FIG>, <FIG>, it can be seen that an opening <NUM> is provided in ceramic body <NUM> which provides exposure through the ceramic body <NUM> to metal sleeve <NUM> which comprises the first polarity electrode when assembled. Thus, the metal sleeve provides an interior electrode surface <NUM> that is exposed to interior chamber <NUM>. It can be understood that in this variation, the working end <NUM> can function in two RF modes as described in the previous reciprocating probe embodiments (see <FIG>). In the first RF mode, the exterior surface <NUM> of outer sleeve <NUM> functions as a first polarity electrode in the interval when the inner sleeve <NUM> and its second polarity electrode edge <NUM> rotates from the window-open position of <FIG> toward the window-closed position of <FIG>. <FIG> depicts this interval of rotation, wherein it can be seen that the first RF mode operates for approximately <NUM>° of rotation of the inner cutting sleeve <NUM>. In this position depicted in <FIG>, the leading edge <NUM> and trailing edge <NUM>' of electrode edge <NUM> are exposed to the open window <NUM> and electric fields EF extend to the first polarity electrode surface <NUM> about the exterior of the probe and plasma is formed at leading electrode edge <NUM> to cut tissue.

The second RF mode is shown in <FIG>, wherein the inner sleeve <NUM> rotates to the window-closed position and the probe switches instantly to such a second RF mode since the electrode edge <NUM> is exposed only to the tissue-receiving lumen <NUM>. It can be understood that the second RF mode operates only when the window <NUM> is closed as in <FIG> and <FIG> which causes the instant explosive vaporization of captured saline in the lumen <NUM>. In <FIG>, it can be seen that the electrode edge <NUM> is exposed only to the interior of lumen <NUM> and electric fields EF extend between the leading and trailing electrode edges (<NUM> and <NUM>') to the exposed electrode surface <NUM> to thus cause the explosive vaporization of captured saline. The vaporization occurs instantly within limited degrees of rotation of the inner sleeve, e.g., <NUM>° to <NUM>° of rotation, upon closing the window <NUM> to thereby expel the resected tissue in the proximal direction as described previously. It has been found that saline captured in the interior channel <NUM> can be distal to the resected tissue or adjacent to the resected tissue in the lumen and the fluid expansion in the liquid-to-vapor transition will instantly expel the resected tissue outwardly or proximally in lumen <NUM>.

<FIG> is a longitudinal sectional view of the working end <NUM> corresponding to <FIG> wherein the electrical fields EF are confined within the interior lumen <NUM> to thus cause the explosive vaporization of captured saline. Thus, the second RF mode and the vaporization of captured saline <NUM> as depicted in <FIG> will expel the resected tissue <NUM> proximally within the tissue extraction channel <NUM> that extends proximally through the probe to a collection reservoir as described in previous embodiments. In general, a method includes capturing a tissue volume in a closed distal portion of an interior passageway of an elongate probe and causing a phase transition in a fluid proximate to the captured tissue volume to expand the fluid to apply a proximally directed expelling force to the tissue volume. The time interval for providing a closed window to capture the tissue and for causing the explosive vaporization can range from about <NUM> second to <NUM> seconds. A negative pressure source also can be coupled to the proximal end of the extraction lumen as described previously.

Now turning to <FIG>, another variation of inner sleeve <NUM>' is shown. In this embodiment, the leading edge <NUM> and the trailing edge <NUM>' of electrode edge <NUM> are provided with different electrical characteristics. In one variation, the leading edge <NUM> is a highly conductive material suited for plasma ignition as described previously. In this same variation shown in <FIG>, the trailing edge <NUM>' comprises a different material which is less suited for plasma formation, or entirely not suited for plasma formation. In one example, the trailing edge <NUM>' comprises a resistive material (e.g., a resistive surface coating) wherein RF current ignites plasma about the leading edge <NUM> but only resistively heats the trailing <NUM>' edge to thus provide enhanced coagulation functionality. Thus, the leading edge <NUM> cuts and the trailing edge <NUM>' is adapted to coagulate the just-cut tissue. In another variation, the trailing edge <NUM>' can be configured with a capacitive coating which again can be used for enhancing tissue coagulation. In yet another embodiment, the trailing edge <NUM>' can comprise a positive temperature coefficient of resistance (PTCR) material for coagulation functionality and further for preventing tissue sticking. In another variation, the trailing edge <NUM>' can have a dielectric coating that prevents heating altogether so that the leading edge <NUM> cut tissues and the trailing edge <NUM>' has no electrosurgical functionality.

<FIG> illustrates another embodiment of inner sleeve component <NUM>' in which the electrode edge <NUM> has a leading edge <NUM> with edge features for causing a variable plasma effect. In this embodiment, the projecting edges <NUM> of the leading edge <NUM> electrode will create higher energy density plasma than the scalloped or recessed portions <NUM> which can result to more efficient tissue cutting. In another embodiment, the electrode surface area of the leading edge <NUM> and trailing edge <NUM>' can differ, again for optimizing the leading edge <NUM> for plasma cutting and the trailing edge <NUM>' for coagulation. In another embodiment, the trailing edge <NUM>' can be configured for volumetric removal of tissue by plasma abrasion of the just-cut surface since it wiped across the tissue surface. It has been found that a substantial amount of tissue (by weight) can be removed by this method wherein the tissue is disintegrated and vaporized. In general, the leading edge <NUM> and trailing edge <NUM>' can be dissimilar with each edge optimized for a different effect on tissue.

<FIG> illustrates another aspect that can be adapted for selective cutting or coagulating of targeted tissue. In this variation, a rotation control mechanism is provided to which can move the inner sleeve <NUM> to provide the leading electrode edge <NUM> in an exposed position and further lock the leading edge <NUM> in such an exposed position. In this locked (non-rotating) position, the physician can activate the RF source and controller to ignite plasma along the exposed leading edge <NUM> and thereafter the physician can use the working end as a plasma knife to cut tissue. In another variation, the physician can activate the RF source and controller to provide different RF parameters configured to coagulate tissue rather that to cut tissue. In one embodiment, a hand switch or foot switch can upon actuation move and lock the inner sleeve in the position shown in <FIG> and thereafter actuate the RF source to deliver energy to tissue.

It should be appreciated that while an RF source is suitable for causing explosive vaporization of the captured fluid volume, any other energy source can be used such as an ultrasound tranducer, HIFU, a laser or light energy source, a microwave or a resistive heat source.

Claim 1:
A system for extracting tissue from a working space in a patient's body, said system comprising:
an elongate shaft assembly (<NUM>) comprising:
an outer sleeve (<NUM>) having a tissue-receiving window (<NUM>) near a distal end thereof, an inner insulative layer (<NUM>), and a distal tip (<NUM>), wherein a distal chamber (<NUM>) is defined by the outer sleeve (<NUM>) and the distal tip (<NUM>) and is configured to capture a liquid volume from the working space;
an inner sleeve (<NUM>) accommodated within a lumen (<NUM>) of the outer sleeve (<NUM>) and configured to reciprocate in the lumen (<NUM>) of the outer sleeve (<NUM>), the distal end of inner sleeve (<NUM>) comprising a first polarity electrode with a distal cutting electrode edge (<NUM>), said inner sleeve further comprising
a tissue extraction lumen (<NUM>), and an exterior insulative layer (<NUM>);
wherein exposed surfaces of the outer sleeve (<NUM>) comprise a second polarity electrode (<NUM>); and
an RF source (<NUM>) connectable to the first polarity electrode and the second polarity electrode;
wherein the system is configured to operate in first and second electrosurgical modes,
wherein in a first mode, the first polarity electrode acts as an active electrode to focus energy about the electrode edge to generate plasma for tissue cutting and the second polarity electrode acts as the return electrode, wherein the system is configured to operate in the first mode when the inner sleeve (<NUM>) is distally advanced past the tissue-receiving window (<NUM>) to cut tissue protruding through the tissue-receiving window and to capture the cut tissue in the tissue extraction lumen (<NUM>) of the inner sleeve (<NUM>);
wherein the system is configured to switch to the second mode when the inner sleeve (<NUM>) entirely crosses the tissue-receiving window (<NUM>),
wherein in the a second mode, the electrode edge (<NUM>) is confined within the chamber (<NUM>) and the system is configured such that an interior surface area (<NUM>) of the distal tip (<NUM>) interfacing the chamber (<NUM>) functions as an active electrode and a distal end portion of the inner sleeve (<NUM>) exposed to the chamber (<NUM>) acts as a return electrode, wherein applying RF energy between the active electrode and the return electrode causes a rapid vaporization of the captured liquid volume to propel the cut tissue proximally through the tissue extraction lumen (<NUM>).