US20100228245A1 - Method and System for Transcervical Tubal Occlusion - Google Patents

Abstract

A medical device and procedure is described for occluding a fallopian tube. A tubal occlusion device is inserted into a uterine cavity. The device includes an RF applicator head including an electrode carrier with one or more bipolar electrodes thereon. During insertion, the RF applicator head can be in a closed position. The RF applicator head is positioned at a tubal ostium of a fallopian tube, such that a distal tip of the RF applicator head advances into the tubal ostium. The RF applicator head is deployed into an open position such that the RF applicator head approximates the shape of the uterine cavity in a region of the tubal ostium. Current is passed through the one or more bipolar electrodes to the tubal ostium to destroy tissue to a known depth, which precipitates a healing response in surrounding tissue that over time scars and occludes the fallopian tube.

Description

CLAIM OF PRIORITY
• This application is a divisional of U.S. application Ser. No. 11/019,580, filed Dec. 20, 2004, now issued as U.S. Pat. No. 7,731,712, which is incorporated herein by reference.
TECHNICAL FIELD
• This invention relates to a medical device and procedure.
BACKGROUND
• Female sterilization typically involves occluding the fallopian tubes to prevent sperm access to an egg within a female's fallopian tube. One conventional female sterilization procedure is laparoscopic tubal occlusion. In this procedure, an incision is made in the abdominal wall to provide access to the fallopian tubes. The tubes are surgically occluded with the aid of a laparoscope, for example, using bipolar or monopolar coagulation. Laparoscopic tubal occlusion is invasive and requires multiple incisions and passing of several instruments and a gaseous distension medium into the patient's abdomen. Thermal and mechanical injury to the surrounding tissues and organs has been reported.
• Minimally invasive transcervical approaches to female sterilization have been used more recently. One such procedure involves placing small, flexible devices into the fallopian tubes; the devices are inserted transcervically into the uterine cavity providing access to the fallopian tubes. The devices are made from polyester fibers and metals and once in place, body tissue grows into the devices and blocks the fallopian tubes. The devices permanently remain in the patient's body, which has raised concerns about the long term effects of the implanted devices as well as restrictions on potential subsequent surgical interventions within the uterus, given the conductive metallic components in the devices.
• A monopolar radio frequency technique has been investigated that included passing a small diameter wire (an active electrode) transcervically through the uterine cavity and the tubal ostium to the fallopian tubes. A large, passive electrode is positioned externally. The current path between the two electrodes is not well defined and can lead to inadvertent burns. The technique was not successful and was abandoned. It could manage neither the varying thicknesses of endometrial tissue at the tubal ostium, nor the required tight tolerance on the depth of destruction within the fallopian tubes.
SUMMARY
• This invention relates to a medical device and procedure. In general, in one aspect, the invention features a method for fallopian tubal occlusion. A tubal occlusion device is inserted into a uterine cavity. The device includes an RF applicator head including an electrode carrier with one or more bipolar electrodes thereon. During insertion, the RF applicator head is in a closed position. The RF applicator head is positioned at a tubal ostium of a fallopian tube such that a distal tip of the RF applicator head advances into the tubal ostium. The RF applicator head is deployed into an open position such that the RF applicator head approximates the shape of the uterine cavity in a region of the tubal ostium. Current is passed through the one or more bipolar electrodes to the tubal ostium to destroy tissue to a known depth, which precipitates a healing response in surrounding tissue that over time scars and occludes the fallopian tube.
• Implementations of the invention can include one or more of the following features. Passing current through the one or more bipolar electrodes to the tubal ostium to destroy tissue can include vaporizing endometrium and destroying superficial myometrium. Inserting a tubal occlusion device into a uterine cavity can include inserting the tubal occlusion device with the RF applicator head in a closed position, and before passing current through the one or more bipolar electrodes, deploying the RF applicator head into the open position. Suction can be applied through the electrode carrier to draw the surrounding tissue into contact with the electrodes, and to draw moisture generated during ablation away from the electrodes to substantially prevent the formation of a low impedance liquid layer at the electrodes. Passing current through the one or more bipolar electrodes can include delivering radio frequency energy to the one or more bipolar electrodes.
• The method can further include automatically terminating the flow of current into the tissue once ablation has approximately reached a predetermined depth of ablation. Before positioning the RF applicator head at the tubal ostium, the uterine cavity can be insufflated. Insufflation is ceased before passing current through the one or more bipolar electrodes, allowing the uterine cavity to collapse onto the RF applicator head. Deploying the RF applicator head into an open position can include removing a sheath to expose the electrode carrier. The electrode carrier can include a fabric having conductive metallized regions and one or more non-conductive regions formed thereon to create the one or more bipolar electrodes. The method can further include advancing an illuminator and an optical instrument into the uterine cavity. Positioning the RF applicator head at the tubal ostium of a fallopian tube can include using the optical instrument to visualize the tubal ostium.
• In general, in another aspect, the invention features a system for fallopian tubal occlusion. The system includes a tubal occlusion device, a source of radio frequency energy, a controller and a vacuum source. The tubal occlusion device has a distal end and a proximal end, the distal end including an electrode carrier with one or more bipolar electrodes thereon. In an open condition the distal end is shaped to approximate a uterine cavity in a region of a tubal ostium of a fallopian tube to be occluded. The source of radio frequency energy is electrically coupled to the one or more bipolar electrodes. The controller is configured to control the delivery of radio frequency energy to the one or more bipolar electrodes such that passing radio frequency energy through the one or more bipolar electrodes to the tubal ostium can be controlled to destroy tissue to a known depth, which precipitates a healing response in surrounding tissue that over time scars and occludes the fallopian tube. The vacuum source is operable to draw the tissue into contact with the one or more bipolar electrodes and to draw moisture generated during delivery of the radio frequency energy to the bipolar electrodes away from the bipolar electrodes. This can substantially eliminate liquid surrounding the bipolar electrodes.
• Implementations of the invention can include one or more of the following features. Passing radio frequency energy through the one or more bipolar electrodes to the tubal ostium destroying tissue can include vaporizing endometrium and destroying superficial myometrium. The electrode carrier can include a structural support member within a fabric sheath having conductive metallized regions and having one or more non-conductive regions formed thereon to create the one or more bipolar electrodes. The structural support member can include flexible members movable between a closed condition and the open condition. The system can further include an illumination source electrically coupled to the distal end of the tubal occlusion device to illuminate the uterus, and an optical instrument electrically coupled to the distal end of the tubal occlusion device to provide images of the uterus.
• In general, in another aspect, the invention features an apparatus for occluding a fallopian tube. The apparatus includes an elongate member, an electrode carrier and a tube. The elongate member has a distal end, a proximal end and a hollow central interior. The electrode carrier is attached to the distal end of the elongate member and has one or more bipolar electrodes formed thereon. The electrode carrier is operable to couple to a radio frequency energy generator and is movable between a closed position in which the electrode carrier is collapsed for insertion into a uterine cavity, and an open position in which a distal end of the electrode carrier is shaped to fit within a tubal ostium of a fallopian tube. The hollow central interior of the elongate member is operable to couple to a vacuum source and to draw moisture away from the one or more electrodes.
• Implementations of the invention can include one or more of the following features. The apparatus can further include an illuminator attached to the distal end of the elongate member and operable to couple to an illumination source, and an optical instrument attached to the distal end of the elongate member and operable couple to an image display device. The electrode carrier can include a structural support member within a fabric sheath having conductive metallized regions and have one or more non-conductive regions formed thereon to create the one or more bipolar electrodes The structural support member can include flexible members movable between a closed condition and the open condition.
• Implementations of the invention can realize one or more of the following advantages. The tubal occlusion procedure described is minimally invasive: the tubal occlusion device can be introduced into the patient's uterine cavity transcervically and requires no abdominal incision. The procedure does not leave any foreign objects in the patient's body, minimizing the risk of infection and eliminating the need to restrict subsequent surgical intervention options. The procedure can be performed quickly, the actual duration of ablation being approximately one minute per fallopian tube. Because the RF energy is limited to the region of ablation, there is less risk of damage to other organs during the procedure. The system and procedure automatically compensate for varying endometrial thicknesses, facilitating the proper, contoured depth of tissue destruction in the region of the tubal opening. Further, unlike the technique described above that implanted permanent devices in the fallopian tubes, there is no need to navigate a catheter through the fallopian tubes, which are prone to spasm, inhibiting the placement of permanent devices, making such a procedure difficult to achieve.
• The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
• FIG. 1A is a schematic representation of a uterus.
• FIG. 1B is a schematic representation of a RF applicator head positioned in a tubal ostium.
• FIG. 1C is a schematic representation of a region of ablated tissue in a uterus and tubal ostium.
• FIG. 2 shows a side view of a tubal occlusion device.
• FIG. 3A shows a top view of the tubal occlusion device ofFIG. 2 with a RF applicator head in a closed position.
• FIG. 3B shows a top view of the tubal occlusion device ofFIG. 2 with the RF applicator head in an open position.
• FIGS. 4A and 4B show one embodiment of a structural body of a RF applicator head in closed and open positions respectively.
• FIG. 4C is a schematic representation of a RF applicator head in an open position.
• FIG. 4D is a schematic representation of center lines of electrodes of the RF applicator head ofFIG. 4C.
• FIG. 4E is a cross-sectional view of a main body of the tubal occlusion device ofFIGS. 2 and 3.
• FIGS. 5A-D are schematic representations of cross-sectional views showing electrodes in contact with tissue for ablation.
• FIG. 6 is a flowchart showing a process for tubal occlusion.
• FIGS. 7A-D are schematic representations of steps of a process for tubal occlusion.
• FIG. 8 is a schematic representation of an alternative embodiment of a structural body of a RF applicator head.
• Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
• A method and system for occlusion of a female's fallopian tubes is described that provides a minimally invasive alternative for female sterilization. Referring toFIG. 1A, a schematic representation of auterus3 is shown, including auterine cavity5 surrounded by uterine tissue, namelyendometrial tissue7aandmyometrial tissue7b. Thefallopian tubes11 connect to theuterine cavity5 at thetubal ostia9. Occluding thetubal ostia9 prevents sperm from entering thefallopian tubes11 and fertilizing an egg, thereby sterilizing the female.
• Referring toFIG. 1B, a RF (radio frequency)applicator head2 can be introduced transcervically into the uterine cavity and positioned at atubal ostium9. Transmitting RF energy through theRF applicator head2 ablates theuterine tissue7a,7band tissue within thetubal ostium9, as shown schematically by theregion11 inFIG. 1C. Following the destruction of tissue at thetubal ostium9, the healing response occludes thetubal ostium9 and the adjacent portion of thefallopian tube11 resulting in sterilization. Referring again toFIG. 1C, the targeted destruction from A-A to B is approximately 1.5 to 2.5 millimeters, from A-A to C is approximately 10 to 20 millimeters, and the depth D-D is typically approximately 2.0 to 3.5 millimeters.
• Referring toFIGS. 2,3A and3B, one embodiment of atubal occlusion device15 is shown. Thetubal occlusion device15 includes generally three major components: theRF applicator head2, amain body4, and ahandle6.FIG. 2 shows a side view of thetubal occlusion device15 andFIGS. 3A and 3B show top views.FIG. 3A shows thetubal occlusion device15 with theRF applicator head2 in a closed position within asheath32 andFIG. 3B shows theRF applicator head2 in an open position outside of thesheath32. TheRF applicator head2 includes anelectrode carrier12 mounted to the distal end of theshaft10 andelectrodes14 formed on the surface of theelectrode carrier12. AnRF generator16 can be electrically connected to theelectrodes14 to provide mono-polar or bipolar RF energy to them.
• Themain body4 includes ashaft10. Theshaft10 is an elongate member having a hollow interior. In one embodiment, theshaft10 is approximately 30 centimeters long and has a cross-sectional diameter of approximately 4 millimeters. Extending through theshaft10 is a suction/insufflation tube17 having a plurality ofholes17aformed in its distal end (seeFIGS. 4A and 4B).
• Referring particularly toFIG. 3B, electrode leads18aand18bextend through theshaft10 from the distal end20 to theproximal end22 of theshaft10. At the distal end20 of theshaft10, each of theleads18a,18bis coupled to a respective one of theelectrodes14. At theproximal end22 of theshaft10, theleads18a,18bare electrically connected to theRF generator16 by anelectrical connector21. During use, theleads18a,18bcarry RF energy from theRF generator16 to theelectrodes14. Each of theleads18a,18bis insulated, and theleads18aand18bcan be connected to opposite terminals of theRF generator16. When opposite polarity is applied to alternating electrodes or groups of electrodes, an electrode pair (i.e., one positively charged and one negatively charged electrode or group of electrodes) can be referred to as a bipolar electrode. Any references herein to a bipolar electrode refer to such an electrode pair.
• Referring toFIGS. 4A-C, theRF applicator head2 can be shaped to approximate the shape of the region to be ablated. The embodiment of theRF applicator head2 shown inFIG. 4C has a V-shape which can fit within a corner of theuterine cavity5 and reach into thetubal ostium9.FIGS. 4A and 4B show theRF applicator head2 without theelectrode carrier12, thereby revealing thestructural body100 of theRF applicator head2. Aflexible member19 is attached to the distal end of theshaft10 of the main body and to the distal end of thetube17. Aflexure22 is attached to thetube17 and to an inner surface of theflexible member19. In the closed position shown inFIG. 4A, theflexure22 is compressed within the space formed between the inner surface of theflexible member19 and thetube17, and the shape of thestructural body100 of theRF applicator head2 is substantially cylindrical. In one embodiment, theflexure22 andflexible member19 are made from stainless steel, are approximately 0.012 inches thick and are substantially planar.
• TheRF applicator head2 can be deployed into the open position shown inFIG. 4B by moving thetube17 relative to theshaft10. In one embodiment, theshaft10 is pulled toward the proximal end of the shaft, i.e., away from theRF applicator head2. Movement of theshaft10, which is connected to theflexible member19, causes theflexible member19 to also move in the same direction, causing theflexure22 to move laterally away from thetube17. As shown inFIG. 4B,flexible member19 is deformed outwardly, away from thetube17, creating the V-shape at the distal end of theRF applicator head2. The shape of the distal end differs depending on how much theshaft10 andtube17 are moved relative to one another.
• In an alternative embodiment, thetube17 can be pushed toward the proximal end of theflexible member19, i.e., toward theRF applicator head2, thereby moving thetube17 relative to theshaft10. The relative movement has the same effect as described above, that is, theflexible member19 is deformed outwardly, creating a V-shape at the distal end.
• FIG. 4C shows the distal end of theRF applicator head2 with theelectrode carrier12 over the structural body. Theelectrode carrier12 can be formed of a fabric that is stretched over the structural body; the fabric is metallized in the regions forming theelectrodes14. Theelectrodes14 are conductive and can alternate between positive and negative polarity (an electrode pair being a “bipolar electrode” as described above). In the embodiment depicted, there are four electrodes14 (or 2 bipolar electrodes), two on either face of theelectrode carrier12. Anon-conductive insulator23 divides theelectrode carrier12 into thebipolar electrodes14.
• In one embodiment, the fabric is formed from a composite yarn with a thermoplastic elastomer (TPE) core and multiple polyfilament nylon bundles wound around the TPE as a cover. The nylon bundles are plated with thin conductive metal layers. Preferably, the nylon is metallized, but not the TPE core. This construction facilitates stretching; the nylon windings open up their coils as the TPE core is elongated, without cracking the metallic layer. The TPE core facilitates recovery from the stretched position, pulling the nylon coils back into their initial configuration.
• In an alternative embodiment, theelectrode carrier12 can be a sack formed of a material that is non-conductive, that is permeable to moisture, and that can be compressed to a smaller volume and subsequently released to its natural size upon elimination of compression. Examples of materials for theelectrode carrier12 include foam, cotton, fabric, or cotton-like material, or any other material having the desired characteristics. Theelectrodes14 can be attached to the outer surface of theelectrode carrier12, e.g., by deposition or another attachment mechanism. Theelectrodes14 can be made of lengths of silver, gold, platinum, or any other conductive material. Theelectrodes14 can be formed on theelectrode carrier12 by electron beam deposition, or they can be formed into coiled wires and bonded to theelectrode carrier12 using a flexible adhesive. Other means of attaching the electrodes, such as sewing them onto the surface of theelectrode carrier12, may alternatively be used.
• Depth of destruction of the target tissue can be contoured to achieve repeatable, predetermined depths. Variables such as the electrode construction, power applied to the electrodes (power density or power per unit surface area of the electrode), and the tissue impedance at which power is terminated can be used to affect the depth of tissue destruction, as discussed further below.
• The spacing between the electrodes (i.e., the distance between the centers of adjacent electrodes) and the widths of the electrodes are selected so that ablation will reach predetermined depths within the tissue, particularly when maximum power is delivered through the electrodes. Maximum power is the level at which low impedance, low voltage ablation can be achieved. For example, referring toFIG. 4D,lines19aand19brepresent center lines of theelectrodes14 of theRF applicator head2 ofFIG. 4C, i.e., the spacing. The center lines diverge and are closest at the distal end I and further apart at the proximal end H. The closer the center lines the shallower the depth of destruction. That is, the depth of destruction at the distal end, which during operation is positioned within or closest to thetubal ostium9, is least.
• Referring toFIG. 5A, preferably each electrode is energized at a polarity opposite from that of its neighboring electrodes. By doing so, energy field patterns, designated52,53 and54 inFIG. 5A, are generated between the electrode sites and thus help to direct the flow of current through the tissue T to form a region of ablation A. As can be seen inFIG. 5A, if electrode spacing is increased by energizing, for example, every third or fifth electrode rather than all electrodes, the energy patterns will extend more deeply into the tissue. See, for example,pattern53 which results from energization of electrodes having a non-energized electrode between them, orpattern54 which results from energization of electrodes having two non-energized electrodes between them.
• The depth of ablation is also effected by the electrode density (i.e., the percentage of the target tissue area which is in contact with active electrode surfaces) and may be regulated by pre-selecting the amount of this active electrode coverage. For example, the depth of ablation is much greater when the active electrode surface covers more than 10% of the target tissue than it is when the active electrode surfaces covers only 1% of the target tissue.
• By way of illustration, by using 3-6 mm spacing and an electrode width of approximately 0.5-2.5 mm, delivery of approximately 20-40 watts over a 9-16 cm²target tissue area will cause ablation to a depth of approximately 5-7 millimeters when the active electrode surface covers more than 10% of the target tissue area. After reaching this ablation depth, the impedance of the tissue will become so great that ablation will self-terminate. By contrast, using the same power, spacing, electrode width, and RF frequency will produce an ablation depth of only 2-3 mm when the active electrode surfaces covers less than 1% of the target tissue area. This can be better understood with reference toFIG. 5B, in which high surface density electrodes are designated51aand low surface density electrodes are designated51b. For purposes of this comparison between low and high surface density electrodes, each bracketed group of low density electrodes is considered to be a single electrode. Thus, the electrode widths W and spacings S extend as shown inFIG. 5B.
• As is apparent fromFIG. 5B, theelectrodes51a, which have more active area in contact with the underlying tissue T, produce a region of ablation A1 that extends more deeply into the tissue T than the ablation region A2 produced by thelow density electrodes51b, even though the electrode spacings and widths are the same for the high and low density electrodes. Some examples of electrode widths, having spacings with more than 10% active electrode surface coverage, and their resultant ablation depth, based on an ablation area of 6 cm²and a power of 20-40 watts, are given on the following table:

• ELECTRODE WIDTH	SPACING	APPROX. DEPTH
  1 mm	1-2 mm	1-3 mm
  1-2.5 mm	3-6 mm	5-7 mm
  1-4.5 mm	8-10 mm	8-10 mm

• Examples of electrode widths, having spacings with less than 1% active electrode surface coverage, and their resultant ablation depth, based on an ablation area of 6 cm²and a power of 20-40 watts, are given on the following table:

• ELECTRODE WIDTH	SPACING	APPROX. DEPTH
  1 mm	1-2 mm	0.5-1 mm
  1-2.5 mm	3-6 mm	2-3 mm
  1-4.5 mm	8-10 mm	2-3 mm

• Thus it can be seen that the depth of ablation is significantly less when the active electrode surface coverage is decreased.
• Referring toFIG. 5C, if multiple, closely spaced,electrodes51 are provided on the electrode carrying member, a user may set theRF generator16 to energize electrodes which will produce a desired electrode spacing and active electrode area. For example, alternate electrodes may be energized as shown inFIG. 5C, with the first three energized electrodes having positive polarity, the second three having negative polarity, etc. All six electrodes together can be referred to as one bipolar electrode. As another example, shown inFIG. 5D, if greater ablation depth is desired the first five electrodes may be positively energized, and the seventh through eleventh electrodes negatively energized, with the sixth electrode remaining inactivated to provide adequate electrode spacing. Therefore, in one implementation, a user can control which electrodes are energized to produce a desired depth of destruction.
• Referring again toFIGS. 3A and 3B, in one implementation, to achieve the desired depth of ablation, a controller included in theRF generator16 can monitor the impedance of the tissue at the distal end of theRF applicator head2 and include an automatic shut-off once a threshold impedance is detected. As the tissue is desiccated by the RF energy, fluid is lost and withdrawn from the region by a vacuum through thetube17, which can be connected to suction/insufflation unit40 via suction/insufflation port38 (FIGS. 3A,3B). The suction draws moisture released by tissue undergoing ablation away from theelectrode carrier12 and prevents formation of a low-impedance liquid layer around theelectrodes14 during ablation. As more tissue is desiccated, the higher the impedance experienced at theelectrodes14. By calibrating theRF generator16, taking into account system impedance (e.g., inductance in cabling etc.), a threshold impedance level can be set that corresponds to a desired depth of ablation.
• Once the threshold impedance is detected, the controller shuts off the RF energy, preventing excess destruction of tissue. For example, when transmitting RF energy of 5.5 watts per square centimeter of tissue, an impedance of the tissue of 50 ohms can indicate a depth of destruction of approximately 3 to 4 millimeters at the proximal end H and approximately 2.5 millimeters at the distal end I. In an alternative embodiment, theRF generator16 can be configured such that above the threshold impedance level the RF generator's ability to deliver RF power is greatly reduced, which in effect automatically terminates energy delivery.
• Referring again toFIGS. 3A and 3B, anintroducer sheath32 facilitates insertion of thetubal occlusion device15 into, and removal of the device from, theuterine cavity5. Thesheath32 is a tubular member that is slidable over theshaft10. Thesheath32 is slidable between a distal condition, shown inFIG. 3A, in which theRF applicator head2 is compressed inside the sheath, and a proximal condition in which thesheath32 is moved proximally to release theRF applicator head2 from inside the sheath32 (FIG. 3). By compressing theelectrode carrier12 to a small volume, theRF applicator head2 can be easily inserted transcervically into theuterine cavity5.
• During use, thesheath32 is retracted from theelectrode carrier12, for example, by moving thedistal handle member34 towards the proximal handle member37 to slide thesheath32 in the distal direction. Moving thedistal handle member34 toward the proximal handle member27 can also advance theshaft10 in the proximal direction. The movement of theshaft10 relative to the suction/insufflation tube17 causes theshaft10 to pull proximally on theflexible member19. Proximal movement of theflexible member19 in turn pulls theflexure22, causing it to move to the opened condition shown inFIG. 3B (see alsoFIG. 4B). In one embodiment, a locking mechanism (not shown) is required to hold the shaft in the fully withdrawn condition to prevent inadvertent closure of theRF applicator head2 during the ablation procedure.
• The amount by which theflexible member19 is deformed outwardly from thetube17 can be controlled by manipulating thehandle6 to slide theshaft10, proximally or distally. The amount by which theshaft10 is slid relative to thetube17 controls the shape of theflexible member19.
• As mentioned above, in an alternative embodiment, thehandle6 can be configured so that thetube17 can be moved distally relative to theshaft10. Distal movement of thetube17 in turn deforms theflexible member19 outwardly. The amount by which theflexible member19 is deformed outwardly from thetube17 can be controlled by manipulating thehandle6 to slide thetube17 proximally or distally, and the amount by which thetube17 moves relative to theshaft10 controls the shape of theflexible member19.
• As shown inFIG. 3A, aflow pathway36 is formed from theRF applicator head2 to the suction/insufflation port38. The proximal end of the suction/insufflation tube17 is fluidly coupled to the flow pathway so that gas fluid may be introduced into, or withdrawn from the suction/insufflation tube17 via the suction/insufflation port38. For example, suction may be applied to thefluid port38 using a suction/insufflation unit40. This causes water vapor within theuterine cavity5 to pass through thepermeable electrode carrier12, into the suction/insufflation tube17 viaholes17a, through thetube17, and through the suction/insufflation unit40 via theport38. If insufflation of theuterine cavity5 is desired, insufflation gas, such as carbon dioxide, may be introduced into the suction/insufflation tube17 via theport38. The insufflation gas travels through thetube17, through theholes17a, and into theuterine cavity5 through the permeableelectrode carrying member12.
• One or more additional components can be provided for endoscopic visualization purposes. For example,lumen42,44, and46 may be formed in the walls of theintroducer sheath32 as shown inFIG. 4E. An optical instrument can be used to provide images from within the uterine cavity. For example, referring toFIGS. 3B and 4E, an imaging conduit, such as a fiberoptic bundle, extends throughlumen42 and is coupled via acamera cable43 to acamera45. Images taken from the camera may be displayed on amonitor47. Anillumination fiber50 can extend throughlumen44 and couple to anillumination source49. The optionalthird lumen46 can be an instrument channel through which surgical instruments may be introduced into theuterine cavity5, if necessary. In an alternative embodiment, one or more of thelumen42,44,46 can be formed in the walls of theshaft10.
• Because during use it is most desirable for theelectrodes14 on the surface of theelectrode carrier12 to be held in contact with the interior surface of theuterine cavity5 andtubal ostia9, theelectrode carrier12 may have additional components inside it that add structural integrity to the electrode carrying means when it is deployed within the body.
• Referring toFIGS. 1A-C,5 and6A-D, aprocess58 for using thetubal occlusion device15 to sterilize a female shall be described. Thetubal occlusion device15 is inserted through the vagina and cervix to the internal as13 at the base of the uterus3 (step59). A gas, e.g., carbon dioxide, is delivered into theuterine cavity5 via the suction/insufflation tube17 from the suction/insufflation unit40 to distend the uterine cavity5 (step60). Thetubal occlusion device15 is then advanced into the uterine cavity5 (step61).
• The user visualizes the targettubal ostium9 on themonitor47 using images provided by the camera45 (step62).FIG. 7A is a schematic representation of what the user may see upon thetubal occlusion device15 entering theuterine cavity5; thetubal ostium9 is a relatively small spot in the distance. As thetubal occlusion device15 advances toward thetubal ostium9, thetubal ostium9 is easier to visualize, as shown inFIG. 7B. The distal end of theRF applicator head2, which is still within thesheath32, is positioned at thetubal ostium9, as depicted inFIG. 7C (step63). Thesheath32 is withdrawn to expose the electrodes14 (step64) and theRF applicator head2 is deployed into the open position (step65), as depicted inFIG. 7D.
• Insufflation is ceased and theuterine cavity5 is allowed to collapse onto the RF applicator head2 (step66). Vacuum can be applied to theRF applicator head2 via the suction/insufflation tube17 to draw the surrounding tissue into contact with the electrodes14 (step67). TheRF generator16 is turned on to provide RF energy to the electrodes14 (step68). The RF energy is ceased once the desired amount of tissue has been ablated (step69). In one implementation, 5.5 watts of RF power is supplied for per square centimeter of electrode surface area until the predetermined impedance threshold is reached, at which point power is terminated.
• Theuterine cavity5 can be insufflated a second time, theRF applicator head2 collapsed into a closed position and thetubal occlusion device15 rotated approximately 180°. TheRF applicator head2 can then be positioned at the othertubal ostium9 and the above procedure repeated to ablate tissue at the othertubal ostium9. Thetubal occlusion device15 is then closed and withdrawn from the patient's body. After ablation, healing and scarring responses of the tissue at thetubal ostia9 permanently occlude thefallopian tubes11, without requiring any foreign objects to remain in the female's body and without any incisions into the female's abdomen. The procedure is fast, minimally invasive, and is highly effective at tubal occlusion.
• Referring toFIG. 8, an alternative embodiment of astructural body70 of theRF applicator head2 is shown. Thestructural body70 includes anexternal hypotube72 and aninternal hypotube74. If implementing thestructural body70 in the embodiment of thetubal occlusion device15 described above, theexternal hypotube72 can be theshaft10 and theinternal hypotube74 can be the suction/insufflation tube17. Acage78 is formed over theinternal hypotube74 configured in a V-shape at thedistal end79 that can reach into atubal ostium9. Thecage78 can be a braided or woven structure made from a memory material, e.g., nitinol.
• Thecage78 can be collapsed into a narrow cylindrical configuration by moving theinternal hypotube74 relative to theexternal hypotube72, e.g., by pushing theinternal hypotube74 distally away from theexternal hypotube72. In a collapsed state thecage78 can fit, for example, within thesheath32 described above, when theRF applicator head2 is placed in a closed position. Once thesheath32 is removed and theinternal hypotube74 is moved back into the open position relative to theexternal hypotube72, the nature of the material from which thecage78 is made expands thecage78 into the desired shape that is depicted. An electrode carrier, such as theelectrode carrier12 made from a metallized fabric described above, can be fitted over thestructural body70, completing the RF applicator head.
• A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims (10)

1. A method for fallopian tubal occlusion, comprising:

inserting a tubal occlusion device including an RF applicator head comprising an electrode carrier with one or more bipolar electrodes thereon into a uterine cavity, the RF applicator head being in a closed position;

positioning the RF applicator head at a tubal ostium of a fallopian tube such that a distal tip of the RF applicator head advances into the tubal ostium and deploying the RF applicator head into an open position such that the RF applicator head approximates the shape of the uterine cavity in a region of the tubal ostium; and

passing current through the one or more bipolar electrodes to the tubal ostium to destroy tissue to a known depth and to precipitate a healing response in surrounding tissue that over time scars and occludes the fallopian tube.

2. The method ofclaim 1, wherein passing current through the one or more bipolar electrodes to the tubal ostium to destroy tissue comprises vaporizing endometrium and destroying superficial myometrium.

3. The method ofclaim 1, wherein inserting a tubal occlusion device into a uterine cavity comprises inserting the tubal occlusion device with the RF applicator head in a closed position, the method further comprising:

before passing current through the one or more bipolar electrodes, deploying the RF applicator head into the open position.

4. The method ofclaim 1, further comprising:

applying suction through the electrode carrier to draw the surrounding tissue into contact with the electrodes and to draw moisture generated during ablation away from the electrodes to substantially prevent the formation of a low impedance liquid layer at the electrodes.

5. The method ofclaim 1, wherein passing current through the one or more bipolar electrodes comprises delivering radio frequency energy to the one or more bipolar electrodes.

6. The method ofclaim 1, further comprising:

automatically terminating the flow of current into the tissue once ablation has approximately reached a predetermined depth of ablation.

7. The method ofclaim 1, further comprising:

before positioning the RF applicator head at the tubal ostium, insufflating the uterine cavity; and

before passing current through the one or more bipolar electrodes, ceasing insufflating the uterine cavity and allowing the uterine cavity to collapse onto the RF applicator head.

8. The method ofclaim 1, wherein deploying the RF applicator head into an open position includes removing a sheath to expose the electrode carrier.

9. The method ofclaim 1, wherein the electrode carrier includes a fabric having conductive metallized regions and one or more non-conductive regions formed thereon to create the one or more bipolar electrodes.

10. The method ofclaim 1, further comprising:

advancing an illuminator and an optical instrument into the uterine cavity; and

wherein positioning the RF applicator head at the tubal ostium of a fallopian tube includes using the optical instrument to visualize the tubal ostium.

Images