US20090125014A1 - Thermal Ablation System - Google Patents

Abstract

A thermal ablation system comprises a fluid handling unit receiving fluid from a fluid source at a first pressure, the fluid handling unit including a heater heating the fluid to a desired temperature and a pump and an introducer including a sheath which, when in an operative position, is received within a hollow organ, the sheath including a delivery lumen introducing fluid heated by the heater to the hollow organ and a return lumen withdrawing fluid from the hollow organ and returning the withdrawn fluid to the console via a return lumen, wherein the pump increases a pressure of the fluid between the fluid source and the delivery lumen of the introducer.

Description

PRIORITY CLAIM
• This application claims the priority to the U.S. Provisional Application Ser. No. 60/987,913, entitled “THERMAL ABLATION SYSTEM,” filed on Nov. 14, 2007. The specification of the above-identified application is incorporated herewith by reference.
BACKGROUND
• Menorrhagia, excessive uterine bleeding during a prolonged menstrual period, has been attributed to disorders of the endometrial lining of the uterus. While a hysterectomy provides a definitive treatment for menorrhagia, physicians and patients may choose less invasive procedures to reduce side effects, prolonged hospital stays and procedural and post-operative discomfort.
• Generally, the less invasive procedures employ electrical energy (e.g., RF energy), heat (e.g., laser) or cryogenic treatment. However, these procedures typically rely on direct visualization of the uterus and an experienced operator applying the energy, heat, etc. to selected portions of the uterine lining. Alternatively, the entire inner lining of the uterus may be treated by conduction uterine ablation, i.e., circulating a heated fluid through the uterus. In other similar procedures, the heated fluid may be contained within a balloon while circulating through the uterus.
SUMMARY OF THE INVENTION
• The present invention relates to a thermal ablation system comprising a fluid handling unit receiving fluid from a fluid source at a first pressure, the fluid handling unit including a heater heating the fluid to a desired temperature and a pump and an introducer including a sheath which, when in an operative position, is received within a hollow organ, the sheath including a delivery lumen introducing fluid heated by the heater to the hollow organ and a return lumen withdrawing fluid from the hollow organ and returning the withdrawn fluid to the console via a return lumen, wherein the pump increases a pressure of the fluid between the fluid source and the delivery lumen of the introducer.
BRIEF DESCRIPTION OF DRAWINGS
• FIG. 1 shows an exemplary embodiment of a thermal ablation system according to the present invention;
• FIG. 2 shows a frontal view of an exemplary embodiment of a console of a thermal ablation system according to the present invention;
• FIG. 3 shows an exploded view of an exemplary embodiment of a console of a thermal ablation system according to the present invention;
• FIG. 4 shows an exploded view of an exemplary embodiment of a right side component of a console of a thermal ablation system according to the present invention;
• FIG. 5 shows an exploded view of an exemplary embodiment of a valve assembly for a console of a thermal ablation system according to the present invention;
• FIG. 6 shows an exploded view of an exemplary embodiment of a front side component of a console of a thermal ablation system according to the present invention;
• FIG. 7 shows an exploded view of an exemplary embodiment of a chassis of a console of a thermal ablation system according to the present invention;
• FIG. 8 shows an outer view of an exemplary embodiment of a cassette of a thermal ablation system according to the present invention;
• FIG. 9 shows an inner view of an exemplary embodiment of a cassette of a thermal ablation system according to the present invention;
• FIG. 10 shows an exemplary embodiment of an introducer of a thermal ablation system according to the present invention;
• FIG. 11 shows an exemplary embodiment of an open loop fluid flow path of a thermal ablation system according to the present invention;
• FIG. 12 shows an exemplary embodiment of a closed loop fluid flow path of a thermal ablation system according to the present invention;
• FIG. 13 shows an exemplary embodiment of fluid flow through a heating chamber in a cassette according to the present invention;
• FIG. 14 shows an exemplary embodiment of an impeller of a thermal ablation system according to the present invention;
• FIG. 15 shows an exemplary embodiment of an impeller of a thermal ablation system according to the present invention; and
• FIG. 16 shows an exemplary embodiment of a cervical seal of a thermal ablation system according to the present invention.
DETAILED DESCRIPTION
• The present invention may be further understood with reference to the following description and to the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to systems, methods and apparatuses for thermally ablating tissue, e.g., tissue lining an inner surface of a hollow organ. In particular, the present invention relates to devices for ablating the endometrial lining of the uterus. However, those of skill in the art will understand that the present invention, or components thereof, may be utilized in prostate treatment (microwave or cyroablation) systems, irrigation systems or other procedure which require infusion of fluid into a patient.
• FIG. 1 shows an exemplary embodiment of athermal ablation system2 according to the present invention. Generally, thesystem2 includes aconsole4 having apole6 extending from an upper portion thereof and astand8 coupled to a lower portion thereof. Thepole6 preferably extends to a predetermined height above theconsole4 so that an intravenous (IV) bag (not shown) hung therefrom will supply fluid to theconsole4 at a desired pressure. The IV bag contains fluid such as saline that will be heated and circulated through the uterus to ablate the endometrial lining. During the ablation procedure, an operator (e.g., physician, nurse, etc.) may be required to substitute the IV bag for IV bags with other fluids depending on stage of the ablation procedure. For example, prior to the procedure an anesthetic fluid may be circulated through the uterus to numb the surgical site. Additionally, after the endometrial lining has been ablated, an analgesic and/or infection preventative solution may be circulated through the uterus. In another exemplary embodiment, IV bags for any fluids required during the procedure may be concurrently attached to thepole6 with the height of thepole6 determining the pressure at which these fluids will be supplied to theconsole4.
• A height of thestand8 on which a fluid supply bag will be hung is preferably variable using a height-adjusting mechanism to control a pressure of fluid reaching the treatment site as will be described below. The height-adjusting mechanism may be a pneumatic lift, a frictional lock, etc., allowing the operator to manually adjust of the height of thestand8. In another exemplary embodiment, the height-adjusting mechanism may comprise an automated height adjustment mechanism controlled by user actuation or automatically by electronic circuitry in theconsole4 based on sensor data, etc.
• In the exemplary embodiment, thestand8 is provided with a mobile base10 (e.g., locking wheels) so that thesystem2 is easily moveable and steerable. However, those of skill in the art will understand that thebase10 may be static or that electronic control and movement of thesystem2 may also be implemented.
• As shown inFIG. 2, theconsole4 according to the present invention comprises ahousing10 encasing electronic circuitry and providing a user interface12 for displaying content (e.g., instructions, procedural data, warnings, etc.) and receiving user input. The user interface12 may comprise a display screen14 (e.g., LCD) and akeypad16 for submitting input to theconsole4. Those of skill in the art will understand that thekeypad16 may be replaced or augmented by dials, switches, a touch screen (or thescreen14 may be made responsive to tactile input) or any other controls operable by the operator of thesystem2. In one exemplary embodiment, a disposable overlay (not shown) may be applied over the user interface12. For example, if thedisplay screen14 is a touch screen and the operator intermittently provides input to the user interface12 by touching thedisplay screen14, an overlay may be used to prevent thedisplay screen14 from becoming damaged or obscured by fluid.
• Thehousing10 may further include ahandle18 for steering the system5 and aslot26 receiving acassette28, which is described below. In the exemplary embodiment, thehandle18 includes analignment beam activator20 which, when pressed, causes a light beam (e.g., laser light) to be emitted from abeam exit port24 on theconsole4. As would be understood by those skilled in the art, the light beam may preferably be oriented horizontally so that, as the height of theconsole4 is adjusted using the height adjusting mechanism on thestand8 until the beam is positioned on a desired portion of the patient's anatomy, the operator will know that theconsole4 is in a desired position relative to the uterus. Making the console4 a desired height off the floor relative to the uterus (e.g., the same height) ensures that a pressure with which the fluid is circulated in the uterus does not exceed a predetermined value. Those of skill in the art will understand that theactivator20 may be disposed adjacent to the user interface12 and/or thekeypad16 may be positioned on thehandle18. Thehousing10 preferably also includes ahook22 for hanging a drainage bag (not shown) from theconsole4. After ablating the endometrial lining, the fluid is discharged into the drainage bag.
• FIG. 3 shows internal components of anexemplary console4 according to the present invention. Thehousing10 of theconsole4 includes afront side30, arear side32, aleft side34 and aright side36. Those of skill in the art will understand that thehousing10 may be comprised of any number of components in any number of geometrical relationships to one another and that the terms front, rear, left and right are relational terms used only to describe the exemplary embodiment of theconsole4. Achassis38 inside thehousing10 acts as an attachment point for thesides30,32,34,36 and supports various electrical components of theconsole4. In this embodiment, thefront side30 includes circuitry powering the user interface12 and thebeam activator20, while therear side32 provides an input for a power source (e.g., line voltage). However, in other exemplary embodiments, thesystem2 may be powered by an on-board battery. Theleft side34 generally comprises a vented wall which allows air heated during operation of the electric components of theconsole4 to be expelled therefrom, while theright side36 includes components that interface with thecassette28.
• FIG. 4 shows an exemplary embodiment of theright side36 of theconsole4 which includes components for interfacing with thecassette28. The cassette interface generally includes avalve arrangement40 and amotor arrangement42. Thevalve arrangement40 includes one or more valves46 (e.g., pinch valves) which engage outer surfaces of flexible tubes within thecassette28 via openings in a rigid housing thereof to selectively open and close the tubes without contacting fluids flowing therethrough. As shown inFIG. 5, anexemplary valve assembly50 is a pinch valve. However, those of skill in the art will understand that the functions of thevalves46 may be performed by any device(s) configured to selectively open and close the tubes in thecassette28 without contacting fluids within the tubes.
• As shown inFIG. 5, thevalve assembly50 includes amotor52 which drives rotation of apinion54 that mates with arack56. Rotation of thepinion54 is translated into axial movement of therack56 in distal (lumen-closing) and proximal (lumen-opening) directions relative to amount block58 with apincher60 coupled to a distal end of therack56. As therack56 is driven distally by the rotation of thepinion54, thepincher60 compresses a respective lumen in thecassette28 against a wall of thecassette28. A position sensor62 (e.g., an optical sensor, Hall effect sensor, etc.) may be included in thevalve assembly50 to determine a position of thepincher60 relative to the respective lumen. In this manner, an amount of closure of the respective lumen and/or an amount of fluid flow permitted through the respective lumen at the amount of closure may be determined. As will be described further below, thesystem2 may utilize the closure information to adjust a volume and/or pressure of fluid circulated through the uterus.
• Referring back toFIG. 4, thevalves46 may include a number ofvalve assemblies50 including similar rack and pinion assemblies and pincher combinations or other mechanisms corresponding to a number of lumens in thecassette28 to be selectively opened and closed. Thevalve arrangement40 may further include asafety valve64 which closes whenever a pressure within the lumen exceeds a predetermined maximum pressure or whenever an unsafe condition is detected.
• Themotor arrangement42 includes a motor66 (e.g., a DC brushless motor), aspeed sensor68 and animpeller coupling70. Current supplied to themotor66 rotates an armature thereof which, in turn, rotates theimpeller coupling70. In one exemplary embodiment, theimpeller coupling70 includes one or more magnets which, when thecassette28 is inserted into theconsole4, are magnetically coupled to one or more magnets on an impeller in thecassette28 so that rotation of theimpeller coupling70 rotates the impeller to drive fluid through thecassette28 and into the patient with no contact between fluid in thecassette28 and components of theconsole4 outside thecassette28. Those of skill in the art will understand that theimpeller coupling70 and the impeller are an exemplary embodiment of any pump arrangement which may be used to output fluid from thecassette28. Thespeed sensor68 may be coupled to themotor66 to detect a rotational speed of the armature thereof to determine, for example, a speed (and/or pressure) at which fluid is being circulated through thecassette28 and/or the uterus.
• As shown inFIG. 6, an exemplary embodiment of thefront side30 of theconsole4 includes the user interface12, thedisplay screen14 and thekeypad16 which may be controlled by a user interface printed circuit board (PCB)70 which interprets user input entered via thekeypad16 and displays the content on thedisplay screen14. Ascreen cover72 may be overlaid on thedisplay screen14 to protect and allow cleansing thereof. The disposable overlay described above is preferably overlaid on thescreen cover72. Aspeaker74 disposed within theconsole4 may be utilized to provide to the operator audible signals such as, for example, voice instructions, warning signals, etc. which, when used in conjunction with the visual content presented on thedisplay screen14 facilitate operation of thesystem2. Additionally, the audible output may be useful when, for example, two persons are working in conjunction to perform the ablation procedure. That is, the operator may be monitoring operation of thesystem2, while a physician and/or nurse may be monitoring the fluid circulation through the uterus. The audible output makes both persons aware of the progress of the ablation procedure regardless their fields of view.
• As shown inFIG. 7, thechassis38 in theconsole4 according to the exemplary embodiment is encased by the right, left, front andrear sides30,32,34,36 of thehousing10. Apower arrangement76 mounted on thechassis38 includes apower PCB78, atoroid80, aline filter82 and apower supply84 coupled to, for example, a port for receiving a line voltage. For example, thepower supply84 may have a power cord extending therefrom to be plugged into a wall outlet, or the port may receive a plug as part of an extension cord. Theline filter82 treats the power to, for example, eliminate surges, harmonic transient currents, spikes, etc. in the current being delivered to theconsole4. The filtered current is then transmitted to thepower PCB78 which distributes power to operational components of thesystem2. Thetoroid80 operates as a transformer, providing electrical isolation between circuits in theconsole4.
• Also mounted on thechassis38 is amotor controller86 which receives instructions from acontroller44 to control operation of themotor66. Thecontroller44, which is shown inFIG. 4, may be a central processing unit which coordinates operation of thesystem2 during the ablation procedure. That is, thecontroller44 may process an instruction set stored in a memory for controlling the user interface12, themotor66, thevalves46, thesafety valve64, etc. during the ablation procedure. An exemplary use of thesystem2 for performing an ablation procedure will be explained in more detail below.
• FIGS. 8 and 9 show an exemplary embodiment of thecassette28 according to the present invention. As noted above, thecassette28 may be embodied in a housing88 sized and shaped to fit within theslot26 on theconsole4. For example, the housing88 may include rails along its sidewalls which are received by guides on the sidewalls of theslot26, allowing thecassette28 to slide thereinto. Once in theslot26, thecassette28 may be mechanically locked in place (e.g., latches, hooks, etc.), gravitationally held in theslot26, magnetically coupled to theconsole4, etc. In one exemplary embodiment, the instructions provided on the user interface12 may instruct the operator on how and when to insert and remove thecassette28. Theconsole4 may lock thecassette28 in theslot26 to prevent removal during an ablation procedure.
• The fluid from the IV bag enters thecassette28 via afluid supply lumen90 which terminates in areservoir92. In this embodiment, alevel sensing board94 is disposed within thereservoir92 for monitoring a volume of fluid therein. During the ablation procedure, thecontroller44 compares the volume to a predetermined volume (or range thereof) to determine whether fluid has been lost/leaked. Based on the results of the comparison, thesystem2 may shut down or execute a predetermined safety procedure. In the exemplary embodiment, thelevel sensing board94 comprises a plurality of level sensors (e.g., capacitors) arranged along a height of theboard94. By analyzing signals received from the level sensors, thecontroller44 may determine the volume of the fluid within thereservoir92.
• The safety procedure may be one or more sets of instructions stored in one or more locations to create a redundant safety net. For example, a primary safety system may be stored as a set of instructions for execution by thecontroller44 so that, when thecontroller44 is alerted to any of a number of predefined faults, the controller initiates the safety procedure and puts the system into a safe state. In addition, a secondary safety system may be included in the form, for example, of a separate non-volatile memory of a complex programmable logic device (CPLD) coupled to thecontroller44 to monitor a watchdog signal therefrom. If a problem arises which compromises the integrity of thecontroller44, the watchdog signal will be compromised as well and the CPLD will put the system into the safe state. The safety procedure may be executed if, for example, thecontroller44 indicates that a component of thesystem2 is non-responsive or otherwise malfunctioning while the secondary system (i.e., the CPLD) will put the system in the safe state when thecontroller44 malfunctions.
• The fluid in thereservoir92 is directed into aheating chamber96 by animpeller98 which, as described above, is rotated by theimpeller coupling70 in theconsole4. As shown inFIGS. 14 and 15, an exemplary embodiment of theimpeller98 includes a plurality ofveins160 disposed on a first surface and a plurality ofmagnets162 disposed on a second surface. Each of theveins160 may be formed as a concave projection on the first surface and have a predefined spacing and angle relative to adjacent veins. In this configuration, the fluid interfacing with theimpeller98 is forced from a center of rotation thereof and into theheating chamber96. Themagnets162 may be embedded in theimpeller98 having exposed surfaces flush with the second surface which magnetically couple to the magnets on theimpeller coupling70. An interface between theimpeller98 and theimpeller coupling70 may be configured so that only the first surface of theimpeller98 comes into contact with the fluid, while the second surface is exposed on (and/or forms a part of) an external surface of thecassette28. Alternatively, theimpeller98 may be fully enclosed within thecassette28.
• Theheating chamber96 includes aheating element100 which heats the fluid therein. Operation of theheating element100 may be based on a temperature measurement of the fluid obtained by a temperature sensor (e.g., thermistor) in theheating chamber96. By monitoring the temperature measurement, thecontroller44 ensures that the fluid temperature is within a predetermined range (e.g., a temperature hot enough to ablate tissue). Those of skill in the art will understand that theheating element100 may further include a cooling element or be deactivated when, for example, the ablation procedure has been completed and the remaining surface tissue in the uterus is to be allowed to cool.
• As shown inFIG. 13, theheating chamber96, in this embodiment, is substantially cylindrical with afluid inlet150 at a lower end thereof. Theinlet150, which receives fluid pumped from theimpeller98, is directed substantially tangential to the cylinder so that the fluid swirls around theheating chamber96 and is heated by theheating element100 as it rises to an outlet at the top of the cylinder. Theheating element100 extends substantially along a longitudinal axis of the cylinder so that the fluid travels around theheating element100 in a substantially helical path as it rises in theheating chamber96, maximizing energy transfer to the fluid.
• When the fluid exits theheating chamber96 it has reached the desired temperature leaving thecassette28 via adelivery lumen102 to pass to an introducer which has been inserted into the uterus. The fluid is then circulated through the uterus and returned to thecassette28 via areturn lumen104. The returned fluid is then passed through afilter106 to remove any tissue remnants, coagulated plasma, etc. and fed back through theimpeller98 into theheating chamber96. By continuously circulating the returned fluid while monitoring any volumes of fluid added/removed from thesystem2, thecontroller44 can detect changes from the initial fluid volume as described above to determine a volume of fluid absorbed into the body. When the ablation procedure has been completed, the fluid is drained into the drainage bag via adrainage lumen110.
• Electrical signals generated by the temperature sensors in theheating chamber96 and the level sensors in the reservoir12 are transferred to thecontroller44 via a communications circuit board108 and digitized. The digitized signals are then converted into procedural data (e.g., temperature data and volume data) which is analyzed by thecontroller44 to monitor the progress of the ablation procedure.
• During progression of the ablation procedure, thecontroller44 configures alternative fluid flow paths through thecassette28 by selectively controlling operation of thevalves46 to open and close the fluid flow lumens therein.FIG. 11 shows an open loop flow path used during priming and/or cooling stages of the ablation procedure. For example, the system primes by opening thesupply valve140 to permit fluid from the IV bag through thecassette28 to thereservoir92 and through theimpeller98 to theheating chamber96 which is inactive at this point through thesafety valve64 into a delivery (not shown) of anintroducer112. The fluid exits the delivery lumen into the uterus and is drawn back from the uterus into a return lumen (not shown) of theintroducer112 which passes the fluid back through thesafety valve64 and out to a drainage bag via adrainage valve142. When the system has been primed, the valves of thecassette28 are reconfigured to the closed loop configuration ofFIG. 12 for heating of the fluid and ablation. Specifically, thedrainage valve142 is closed so that fluid circulates from thereservoir92, through theimpeller98 and theheating chamber96 and into the uterus via thesafety valve64 and theintroducer112. The fluid returning from the uterus via thereturn lumen104 of theintroducer112 passes through thesafety valve64 and thefilter106 to return to thereservoir92 via themiddle valve144 and continues to circulate through this path during the ablation procedure. In this configuration, theheating chamber96 is active to raise the temperature of the fluid to a desired level for ablation. In addition, in this configuration, thebypass valve146 is opened when necessary to bleed off excess flow from the output from theheating chamber96 returning this bled-off fluid to thereservoir92 without passing through the uterus. When the procedure has been completed, thedrainage valve142 is opened and thebypass valve146 and themiddle valve144 are closed to return thesystem100 to the open-loop configuration ofFIG. 11. Theheating chamber96 is deactivated at this point so that fluid currently circulating in thecassette28 flows through the uterus and passes through thedrainage valve142 to the drainage bag without further heating. After this fluid has been drained, fresh fluid from the IV bag is passed through thecassette28 into the uterus at substantially room temperature to flow out into the drainage bag until a desired amount of cooling has been achieved.
• As shown inFIG. 10, anintroducer112 according to an exemplary embodiment of the present invention is coupled to thecassette28 viatubes103 and105 to deliver fluid to the uterus and to return the fluid from the uterus to thecassette28. Thetubes103,105 are coupled to delivery and returnlumens102,104, respectively, of thecassette28 and to fluid delivery and return lumens (not shown) within asheath113 of theintroducer112. The fluid delivery and return lumens of theintroducer112 terminate at respective openings at adistal end118 of thesheath113 which, when theintroducer112 is in an operative positions, is located within the uterus. Theintroducer112 may optionally include a vision system to allow visualization of the operative area. Those of skill in the art will understand that the vision system may be substantially similar to the systems in conventional endoscopes (e.g., fiber optic or CCD-based systems). Alternatively, users may rely on the vision system of an endoscope or other instrument inserted through theintroducer112, as described below.
• Theintroducer112 includes a grip114 (e.g., an ergonomic handle) coupled to thesheath113 and ascope connector116 for receiving a visualization device, such as an endoscope. Thegrip114 facilitates holding and manipulation of theintroducer112 with a single hand while the operator uses his free hand to interface with theconsole4, adjust the visualization device, manipulate the patient's anatomy, etc. Thescope connector116 according to this embodiment is disposed on a proximal end of theintroducer112 and provides an attachment point for the visualization device (e.g., a hysteroscope, an endoscope) so that the visualization device may be passed distally through a visualization lumen in theintroducer112 and extended out of thedistal end118. Thus, the operator may visually monitor insertion of theintroducer112 into the uterus.
• Thescope connector116 may comprise anoptional locking ring117 and ascope adapter120 which allow theintroducer112 to be adjusted to accommodate visualization devices of varying lengths. The visualization device is inserted into the proximal end of theintroducer112 through thescope connector116 and locked thereto using thelocking ring117. The user then depresses thescope adapter120 releasing thescope adapter120 from a current locking aperture121. This allows thescope connector116 to slide proximally out of or distally into theintroducer112 so that, when the visualization device has been inserted through thesheath113 to a desired position in the uterus, thescope connector116 supports the portion of the visualization device extending out of the introducer (e.g., a proximal end of an endoscope immediately distal of the control handle). Those of skill in the art will understand that thescope connector116 may be implemented as any mechanism which allows the length of theintroducer112 to be adjusted to and maintained at a new length. For example, as shown inFIG. 10, thescope adapter120 is formed as a projection on an outer surface of a distal portion of thescope connector116 received in and movable between one of a number of locking apertures121 formed on thegrip114. Partial barriers may be formed between each of the locking apertures121 to retain thescope adapter120 in a selected one of the locking apertures121 maintaining a selected length of a portion of thescope connector116 projecting from the proximal end of theintroducer112. In another embodiment, a rack may be formed on the distal portion of thescope connector116 mating with a gear in thegrip114 so that rotation of the gear extends and withdraws thescope connector116 relative to thegrip114. A ratchet may be provided to maintain the gear in a fixed position relative to the rack, thereby maintaining the desired position of thescope connector116 relative to thegrip114.
• Thegrip114 may further include anoptional tenaculum stabilizer122. For example, during the ablation procedure, a tenaculum may be employed around the cervix to enhance the seal of the cervix around thesheath113 of theintroducer112. A tenaculum that has been clamped around the cervix may then be coupled to theintroducer112 to ensure that theintroducer112 remains at a desired position within the uterus and is not inadvertently withdrawn therefrom. That is, it is important to make sure that the distal end of thesheath113 is not withdrawn proximally from the uterus during the procedure or non-targeted tissue will be exposed to the ablation fluid. Thus, a portion of the tenaculum is passed over thetenaculum stabilizer122 preventing movement of thesheath113 proximally relative to the tenaculum. That is, once a tenaculum has been locked in position on tissue, the tenaculum can be slipped over thetenaculum stabilizer122. Thetenaculum stabilizer122 is moved to a proximal-most position permitted by the tenaculum. Specifically, in the exemplary embodiment, thetenaculum stabilizer122 includes a fin slidably mounted on arail124 formed on thegrip114. The fin includes a hook which may receive finger grips or a crossbar of a tenaculum as would be understood by those skilled in the art. When the tenaculum is coupled to thetenaculum stabilizer122, the operator selects a tension to be applied between the tenaculum and theintroducer112 by moving the fin along therail124. A positioning mechanism (e.g., ratchet, latch, clip, etc.) may be used to maintain a position of the fin relative to therail124, as would be understood by those skilled in the art. Such a tenaculum stabilizer device is described in a U.S. Patent Application Ser. No. 60/971,409, entitled TENACULUM STABILIZER DEVICE, naming as inventors Christopher L. Oskin, Brian MacLean, Stephen Keaney, Jozef Slanda and Jeffrey Zerfas filed Sep. 11, 2007. The entire disclosure of this application is hereby incorporated by reference herein.
• Theintroducer112 may further include an optionalcervical seal126 separated from a distal end of thesheath113 by a distance selected to ensure that, when the distal end of thesheath113 is in a desired position within the uterus, theseal126 is located within the cervix proximal to the cervical os C. When thedistal end118 of theintroducer112 is introduced into the uterus, the elasticity of the cervix provides a substantially fluid-tight seal around thesheath113. However, to minimize the risk of ablation fluid escaping through the cervix to damage non-targeted tissue, the fluid-tight seal may be enhanced/maintained using thecervical seal126. In the exemplary embodiment, thecervical seal126 is formed as aflexible membrane127 which overlies awire mesh129, a proximal end of which abuts a distal end of anexpander member130. A distal end of thecervical seal126 is fixed to thesheath113 while a proximal end is slidable along thesheath113.
• Aseal actuator128 comprises a ring rotatably mounted on thesheath113 and coupled to theexpander member130 which, in this embodiment, is formed as an oversheath telescopically mounted over thesheath113. The ring may be coupled to the oversheath in such a manner that rotation of the ring moves the oversheath proximally and distally over thesheath113. For example, an outer portion of the proximal end of the oversheath may be threaded to mate with threads on an inner portion of the ring of theseal actuator128 so that, when the ring is rotated in a first direction, theexpander member130 slides distally along thesheath113 pushing the proximal end of themesh129 distally causing thecervical seal126 to expand radially away from thesheath113.
• As shown inFIG. 16, it is preferable that expansion of thecervical seal126 is executed when it is within the cervix proximal of the cervical os C so that none of the targeted tissue is covered by theseal126. In the exemplary embodiment, thesheath113 is moved distally until thedistal end118 thereof is within the uterus. Thesheath113 is then withdrawn proximally to minimize a projection of thesheath113 into the uterus maximizing a field of view of the vision system. While in this position, thecervical seal126 is positioned entirely within the cervix with a distal end of theseal126 proximal of the cervical os C. Theexpander member130 engages the proximal end of thecervical seal126 and pushes the proximal end distally along thesheath113 into the expanded position shown inFIG. 16. In the expanded position, themembrane127 substantially engages an inner wall of the cervix enhancing the seal provided by the natural resilience of the wall of the cervix. The distance between thedistal end118 and the distal end of thecervical seal126 is preferably between 0 and 1.5 cm which the seal is actuated. Aseal126 according to an exemplary embodiment of the invention may extend from a proximal end approximately 5 cm from thedistal end118 with a maximum diameter of theseal126 corresponding to a distance of 1.5 cm from thedistal end118.
• Rotation of the ring in a second direction withdraws theexpander member130, allowing thecervical seal126 to return to its unexpanded state through the bias of themesh128 which tends toward the unexpanded state. Alternatively, the proximal end of themesh129 may be coupled to the distal end of theexpander member130 so that, as theexpander member130 is moved proximally, themesh129 is drawn back into the unexpanded state against a bias of themesh128 which tends to expand theseal126.
• In an exemplary use, thesystem2 according to the present invention may be used to ablate the endometrial lining of the uterus. When theconsole4 is activated, thedisplay screen14 may show (and thespeaker74 may provide) a pre-operative instruction set. For example, the instruction set may prompt the operator to hang the IV bag and the drainage bag. Thecontroller44 may then detect whether thecassette28 has been inserted into theslot26 and provide instructions regarding a procedure for connecting thecassette28 to the IV bag, the drainage bag and theintroducer112. In addition, thecontroller44 may determine, upon detecting the presence of thecassette28, whether thecassette28 has been previously used and prevent operation or take other pre-ordained steps if prior use is detected.
• The pre-operative instruction set may also instruct the operator to adjust a height of theconsole4 to be substantially equal with a height of the uterus or to achieve some other desired relationship between the height of theconsole4 and that of the uterus. In the exemplary embodiment, the height of theconsole4 is varied by adjusting thestand8 using a light beam (e.g., laser) emitted from thebeam exit port24 to ensure that theconsole4 is level with the uterus. When theconsole4 is level with the uterus, the operator may initiate the ablation procedure by inserting theintroducer112 into the uterus via the cervix and expanding thecervical seal126 within the cervix. Thecontroller44 may then configure thecassette28 for the open loop flow path by opening the fluid supply anddrainage valves140,142 and circulate a pre-operative fluid through the uterus, priming the endometrial lining for ablation.
• During a heating stage of the ablation procedure, the fluid from the IV bag enters thecassette28 and is heated to a predetermined temperature (e.g., approximately 85-90□C) as indicated by signals generated by the temperature sensors in theheating chamber96 and transferred to thecontroller44 in theconsole4 via the communications board108. The signals may be digitized and analyzed to determine when the fluid has reached the predetermined temperature. Prior to the fluid being heated, thecontroller44 configures thecassette28 for the closed loop flow path by closing the fluid supply anddrainage valves140,142 and opening themiddle valve144 so that fluid returning from the uterus is fed back into thereservoir92, as described above.
• When the fluid has reached the predetermined temperature, theconsole4 initiates a treatment stage circulating the heated fluid through theintroducer112 into the uterus to ablate the endometrial lining as described above in regard toFIG. 12. The heated fluid is delivered to the uterus via the delivery lumen in thesheath113, removed from the uterus via the removal lumen in thesheath113 and returned to theconsole4 where it is filtered by thefilter106 and returned to be circulated through the uterus for a predetermined duration (e.g., approximately 10 minutes) to ablate the endometrial lining. The treatment stage may further include a cooling cycle in which the heated fluid is allowed to cool and then circulated through the uterus to absorb heat from the exposed tissue aiding in the healing process. When the treatment stage has been completed, theconsole4 employs a drain cycle, emptying the fluid in the system into the drainage bag.
• Those of skill in the art will understand that various hardware and software-based variations may be implemented in the system5 according to the present invention. For example, the height-adjusting mechanism on thestand8 may be controlled by position data generated by a position sensor on theintroducer112. After theintroducer112 has been inserted into the uterus, the position data may be analyzed to determined a height of the introducer above the floor. If the height of theconsole4 is not properly aligned with the height of theintroducer112, an alarm may be activated or an automatic height adjusting mechanism may adjust the height of theconsole4 to the desired level. In addition, a pressure transducer may be coupled to thedistal end118 of theintroducer112 to sense the fluid pressure within the uterus. The pressure transducer may provide pressure data to thecontroller44 which determines whether the pressure is within a predefined operable range, and if the pressure is outside of the range, thecontroller44 may execute a safety procedure.
• The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. For example, the invention is not limited to methods and devices for the thermal ablation of the uterine lining. Accordingly, various modifications and changes may be made to the embodiments. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.

Claims (29)

1. A thermal ablation system comprising:

a fluid handling unit receiving fluid from a fluid source at a first pressure, the fluid handling unit including a heater heating the fluid to a desired temperature and a pump; and

an introducer including a sheath which, when in an operative position, is received within a hollow organ, the sheath including a delivery lumen introducing fluid heated by the heater to the hollow organ and a return lumen withdrawing fluid from the hollow organ and returning the withdrawn fluid to the console via a return lumens wherein the pump increases a pressure of the fluid between the fluid source and the delivery lumen of the introducer.

2. The system according toclaim 1, wherein the fluid handling unit includes a reusable console and a disposable cartridge.

3. The system according toclaim 1, wherein the pump increases the pressure of the fluid by a substantially constant amount.

4. The system according toclaim 2, wherein a motor of the pump is located in the console and an impeller of the pump is located within the cartridge.

5. The system according toclaim 4, wherein the motor drives the impeller via a magnetic coupling.

6. The system according toclaim 2, wherein no fluid passes through the console.

7. The system according toclaim 1 wherein the fluid handling unit is mounted on a variable height base.

8. The system according toclaim 3, wherein the console includes a fluid bag mounting pole for mounting the fluid source a predetermined height above a fluid inlet of the fluid handling unit to achieve a desired substantially constant fluid pressure within the hollow organ.

9. The system according toclaim 1, wherein the fluid handling unit includes a user interface including at least one of a display screen, a touch screen, a keypad and a speaker.

10. The system according toclaim 1, wherein the fluid handling unit includes a height determining mechanism ensuring a desired height differential between the fluid source and the hollow organ.

11. The system according toclaim 10, wherein the height determining mechanism provides a visual indication of a reference height relative to the hollow organ.

12. The system according toclaim 11, wherein the height determining mechanism includes a light beam port projecting a light beam substantially horizontally.

13. The system according toclaim 2, wherein the console includes a valve arrangement selectively opening and closing fluid circulation lumens in the cartridge.

14. The system according toclaim 14, wherein the valve arrangement includes at least one pincher valve.

15. The system according toclaim 2, wherein the cartridge includes a filter arrangement filtering the fluid from the return lumen.

16. The system according toclaim 2, wherein the cassette includes a reservoir storing the fluid and a level sensor outputting a signal corresponding to a level of the fluid within the reservoir.

17. The system according toclaim 16, wherein the console includes a controller determining a fluid volume as a function of the signal.

18. The system according toclaim 2, wherein the cartridge includes a drainage lumen emptying fluid from the return lumen into a drainage bag.

19. The system according toclaim 1, wherein the introducer includes a grip having a sheath extending distally therefrom and a scope connector extending proximally therefrom.

20. The system according toclaim 19, wherein the grip is sized and shaped for single-handed use.

21. The system according toclaim 19, wherein the scope connector includes a lock for detachably coupling a visualization device to the introducer and a scope adapter adjusting a length of the introducer.

22. The system according toclaim 19, wherein the sheath includes a seal disposed proximally of a distal end of the sheath.

23. The system according toclaim 22, wherein the seal is radially expandable from the sheath.

24. The system according toclaim 22, wherein a distance between the distal end of the sheath and a distal end of the seal is selected so that, when the distal end of the sheath is in a desired position within the hollow organ, the seal is located within a lumen through which the sheath is introduced into the hollow organ.

25. The system according toclaim 24, wherein the hollow organ is a uterus and the distance is between 0 cm and 1.5 cm so that, when the distal end of the sheath is in a desired position within the uterus, the seal is located within a cervix.

26. The system according toclaim 1, wherein the introducer includes a tenaculum stabilizer.

27. A method, comprising:

aligning a fluid handling unit of a thermal ablation system to a desired height relative to a hollow organ to be treated;

heating a fluid in the fluid handling unit to a predetermined temperature;

pumping the fluid from the fluid handling unit via a fluid delivery lumen into an introducer inserted into the hollow organ; and

after the fluid has been circulated through the hollow organ, withdrawing the fluid from the tissue structure to the fluid handling unit via a fluid return lumen in the introducer.

28. The method according toclaim 27, further comprising:

filtering the fluid received from the fluid return lumen; and

pumping the fluid back into the introducer via the fluid delivery lumen.

29. The method according toclaim 27, further comprising:

monitoring a volume of the fluid circulating through the hollow organ; and

when the volume is outside a predetermined range, executing a safety procedure.

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