WO2000000100A1

WO2000000100A1 - Endometrial balloon ablation catheter having heater

Info

Publication number: WO2000000100A1
Application number: PCT/US1999/007239
Authority: WO
Inventors: Chao Chen; E. Richard Skula; Ettore M. Carino
Original assignee: Ethicon, Inc.
Priority date: 1998-06-30
Filing date: 1999-04-01
Publication date: 2000-01-06
Also published as: AU3378499A

Abstract

A system for thermal ablation of endometrial tissue consisting of a distensible bladder (40), a catheter (20) containing one or more lumens to which the bladder (40) is attached, a heating element (120) located within the catheter, a catheter handle (50), and a control unit (200) detachably connected to the handle (50). The control unit (200) contains any necessary power supplies as well as temperature, fluid pressure, and other control and readout devices (210). The handle (50) and the catheter (20) serve as a conduit for the power supply, control (200) and readout devices (210). The handle (50) also contains a port (52) through which saline or other physiologically acceptable liquid may be introduced under pressure sufficient to inflate the bladder (40) to a desired pressure. The heating element (120) is located in the catheter (20) proximal to the bladder (40). The bladder (40) itself may be permanently attached to the catheter (20) or it may be designed to be removable.

Description

ENDOMETRIAL BALLOON ABLATION CATHETER HAVING HEATER

FIELD OF THE INVENTION

This invention relates to medical devices for ablating tissue, more particularly to a balloon ablation device for ablating endometrial tissue

BACKGROUND OF THE INVENTION

Menorrhagia is a medical condition in women which manifests symptoms including excessive and difficult to control bleeding of the endometrial layer of the uterus The endometrium is usually thought of as the inner lining of the uterus to which an embryo normally attaches and, typically excludes the portion of the uterine inner lining forming the cervix The symptoms of menorrhagia are believed to be experienced by a significant segment of the female population Accordingly, a number of treatments have been developed over the years to remediate this condition One radical procedure, i e , hysterectomy, requires the complete surgical removal of the uterus This surgical procedure has been the treatment of choice in the past and continues to be the ultimate solution if this condition is otherwise non- responsive Because of the extremity and seriousness of this operation, both, in terms of physical and mental effects, attempts have been made to develop less invasive, less radical approaches to relieving menorrhagia

These less invasive approaches have been typically directed at inducing necrosis of the endometrial layer and a portion of the myometrial layer Known procedures include, inter alia, mechanically scraping the endometrial surface, freezing of the endometrial layer cryogenically, cauterizing the endometrial layer of the uterus by means of a laser hysteroscope, treating the uterus with microwave generated heat, and ablating the endometrial tissue with an electrosurgical probe In addition, another known technique involves necrotizing the endometrial tissue by the application heat, for example, using a liquid filled expandable balloon or directly contacting the endometrium with hot liquid

The existing cryogenic methods typically require a device having a probe or an extendable bladder which is inserted into the uterus and filled with a circulating gas or fluid at cryogenic temperatures The cryogenic coolant is typically liquid nitrogen or Freon which is maintained at a sufficient pressure to expand the bladder into close contact with the endometrium Such a procedure is disclosed in U S Patent No 3,924,628

Other known endometrial ablation procedures involve the use of laser devices, these devices require considerable skill by the surgeon A relatively narrow laser beam must be moved so as to cover the whole surface of the endometrium, which may be rather tedious and time consuming Additionally, care must be taken to apply the appropriate dosage of radiation If the dosage is too lovv, the treatment may be incomplete and bleeding may recur, if too high, the laser may bum too deeply into the uterus or even perforate it

Another technique involves heating the endometrium with microwaves This technique has proven to be complex and possibly unreliable because of the irregular shape of the uterus, which makes even energy distribution difficult. The large flow of blood from the endometrium may result in temperature drops due to the cooling effect of the blood The cooling effects need to be compensated for in order to prevent uneven heating Another known treatment technique utilizes a balloon and heated liquid The balloon is mounted to the distal end of a catheter that is inserted into the patient's uterus The balloon is inflated with a liquid, such that the walls of the balloon are substantially in intimate contact with the endometrial layer of the uterus The liquid is then heated to an elevated temperature so as to cause necrosis and ablation of the cells on the endometrial surface The liquid may also be heated prior to inflation of the balloon U S Patent No 5,084,044 describes a method for the ablation of tissue in which a distensible balloon, affixed to the end of a catheter, is inserted into a body cavity and inflated using a source of externally heated liquid This requires that at least part of the catheter be well insulated so as not to burn adjacent healthy tissue for example in the cervix or the vagina

U S Patent No 4,949,718 discloses an apparatus for effecting necrosis of a tissue lining of a body cavity, specifically the uterine endometrium, by introducing a distensible bladder connected to a catheter into the uterus The bladder is expanded by introducing a non-toxic, biocompatible fluid under pressure, heating the fluid in the bladder by means located internal to the bladder and controlling the pressure of the fluid and its temperature U S Patent No 5, 105,808 discloses a method of using this apparatus to effect cauterization necrosis of the uterine endometrium and other body cavities U S Patent No 5,460,628 discloses a balloon treatment apparatus with a means for agitating the fluid within the extended balloon in order to better control the heat to which the endometrium is exposed International Publication No WO 96/33664 describes a similar apparatus for endometrial ablation and, in particular, describes the heating element within the extendable bladder U S Patent No 5,571, 153 discloses a balloon and catheter treatment apparatus

Although the balloon catheter devices having internal heaters are safe and effective for their intended use ( i e , primarily endometrial ablation), there may be some potential advantages associated with placing the heating element outside of the balloon bladder. Since there is a variation in size and, to some extent, in shape of the human uterus it would be preferable to make available devices with differently sized and shaped expandable balloons. The balloon material must be both expandable and sufficiently rugged so as to be able to exert the desired pressure on the endometrial tissue on all of the walls of the irregularly shaped uterus so as to effect intimate contact with said tissue If the bladder is too small, it may not be able to contact all of the walls at its full extension. Conversely, if it is too large for the uterus, it may not be able to make intimate contact in all areas of the endometrium because of folds which might be present on the balloon if it has not been fully extended.

U.S. Patent No. 5,653,692 discloses an endometrial ablation device in which heated fluid contacts the endometrial layer directly. The fluid is introduced at about room temperature and is heated within the uterus by means of electrodes which release RF energy. The fluid is agitated with an impeller located within the uterus itself. This may appear to resolve the problem of differently sized uteri but, actually, introduces a number of other difficulties, e.g., undesirable influx into the fallopian tubes.

The inflatable balloon devices, described above, have the balloon permanently affixed to a catheter which has passages that supply the fluid for the expansion of the balloon. The passages also supply the energy source for heating the fluid and the feedback devices which allow for control of the various functions needed to successfully expand the balloon and heat and agitate the fluid within the balloon. The endometrial ablation devices using liquid filled balloons and heaters internal to said balloons may occasionally encounter problems as well. Holes or even breaks in the balloon are theoretically possible because the material of construction has to be thin walled in order to be usable in variously sized uteri. Such breaks are not harmful to the patient since the liquid which now comes into direct contact with the endometrium is generally aqueous and physiologically compatible and is at or below the desired temperature. The liquid then merely drains out of the uterus forcing the physician to repeat the procedure with a new instrument. Occasionally it may also be possible that a portion of the balloon is in contact with the heating element when the heating cycle is started. This too may lead to puncture of the balloon with consequences as described above. In order to be able to pass through the cervical os, the heating elements are typically made narrow and long and of relatively delicate wire Mishandling of the instrument may cause the heating wire to break in transport thus resulting in an unusable instrument.

The placement of the heating device within the balloon itself may limit the design flexibility of the balloon. Currently the resistance heating elements used within the balloon are designed to be narrow, so as to be easily introduced through the cervical os, and consist of relatively fine wire coils. Placement of the heating element within the catheter, such that the heating element is proximal to the balloon and no portion of the heater protrudes past into the balloon would have advantages.

Accordingly, there is a need in this art for improved uterine catheter balloon devices. 00/00100

SUMMARY OF THE INVENTION:

Therefore, it is an object of the present invention to provide a uterine balloon apparatus for use in endometrial ablation surgical procedures which is economical to manufacture.

It is yet a further object of the present invention to provide a uterine balloon apparatus which has a heater that is positioned in the catheter proximal to the balloon.

It is still yet a further object of the present invention to provide a uterine balloon apparatus having a catheter which has a minimal diameter to facilitate access into the uterus

It is still yet another object of the present invention to provide a uterine balloon apparatus which allows the use of a large heater.

Yet another object of the present invention is to provide a uterine balloon apparatus which eliminates the possibility of the balloon contacting a heater element while inserted in a uterus.

Accordingly, a novel uterine balloon catheter apparatus is disclosed. The uterine balloon treatment apparatus has a catheter having a longitudinal internal passage or lumen, a distal end and a proximal end. An inflatable balloon mounted to the distal end of the catheter. The inflatable balloon has an interior, wherein the interior of the inflatable member is in fluid communication with the internal lumen of the catheter. A hollow cylindrical handle having an internal passage is mounted to the proximal end of the catheter, such that the lumen of the catheter and the 00/00100

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internal passage of the handle are in fluid communication A connector is mounted to the handle for connecting the internal passage of the handle and the internal lumen of the catheter to a source of liquid A heating element is mounted in the interior lumen of the catheter such that when said heating element is connected to a source of electrical power it generates heat The heating element is located proximal to the balloon Electrical conductors are provided for conducting electrical power to the heating element

Another aspect of the present invention is a uterine ablation catheter The uterine balloon treatment apparatus has a catheter having a longitudinal internal passage or lumen, a distal end and a proximal end An inflatable balloon is mounted to the distal end of the catheter The inflatable balloon has an interior, wherein the interior of the inflatable member is in fluid communication with the internal passage or lumen of the catheter A hollow cylindrical handle having a longitudinal passage is mounted to the proximal end of the catheter, such that the longitudinal passages of the handle and the catheter are in fluid communication A connector is mounted to the handle for connecting the internal passage of the handle and the lumen of the catheter to a source of liquid A heating element is mounted in the interior passage of the handle such that when said heating element is connected to a source of electrical power it generates heat Electrical conductors are provided for conducting electrical power to the heating element

Yet another aspect of the present invention is a uterine balloon catheter having a heater proximal to the balloon, wherein the balloon is removably attached to the distal end of the catheter

Still yet another aspect of the present invention is a method of using the above described apparatuses to ablate endometrial tissue There are numerous advantages associated with the novel uterine balloon catheters of the present invention. The novel placement of the heater will allow a stronger balloon to be used. 1 1 is possible to use of a variety of balloon designs without the need for re-designing the heater. It is now possible to make only the balloon portion disposable thus allowing re-use of the major portion of this apparatus. Also, it is now possible to use robust heating elements not subject to in- transit damage.

Other advantageous features of the apparatus of the present invention include, inter alia, that with the heater removed from the balloon end, the size of the portion to be introduced through the cervical os is considerably reduced. Because of this reduction in size, a balloon made out of thicker material is possible and would reduce the potential of balloon damage. Damage to a balloon as a consequence of contacting a very hot heater surface is eliminated. Furthermore, balloons of sizes and shapes appropriate to the individual uterus size and shape can be readily utilized without the constraints imposed by an internal heater

Placement of the heating device far enough back within the catheter or within the handle so that it is in the vagina but just outside the cervical canal, allows the catheter to contain an enlarged portion capable of housing a very rugged and reusable heater.

Placement of the heater toward distal end of the catheter (near but proximal to the balloon) allows adequate heating of the fluid as it is pushed through the heating element while filling the balloon or while being recirculated . The foregoing and other features and aspects of the present invention will become more apparent by the following description and accompanying drawings

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG 1 is a perspective view of an embodiment of an endometrial uterine ablation catheter system of the present invention including a control module

FIG 1A is a cross-sectional view of the handle of the apparatus of FIG 1

FIG 2 illustrates a side view of an embodiment of a uterine ablation catheter of the present invention

FIG 3 illustrates a partial cross-sectional view of an inflated balloon of the present invention positioned within the uterus having the heating element near the distal end of the catheter

FIG 4a is a partial cross-sectional view of a catheter of the present invention illustrating the position of a heater within the catheter

FIG 4b is a partial cross-sectional view of a catheter of the present invention illustrating an alternate positioning of the heater

FIG 5A illustrates a partial cross-sectional view of another embodiment of the present invention wherein the heating element located in the proximal end of the catheter such that it is situated just outside of the uterus FIG. 5B illustrates a detailed view of the heating element section of catheter of FIG 5A

FIG 6 is a partial view of a catheter of the present invention having a 5 detachable balloon

FIG 7 is an alternate embodiment of the apparatus of the present invention wherein the heater is mounted in the handle

l o DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

U S Patent Nos 4,949,718, 5,105,808, 5,460,628, and International Publication No WO 96/33664 are hereby incorporated in their entireties by reference

15

Referring now to the drawings in greater detail, wherein like reference numerals designate like or corresponding elements among the several views, Fig 1 illustrates an overall perspective view of a uterine catheter balloon ablation device 10 of the present invention connected to control unit 200 FIG 1A provides a

20 detail of the handle 50 in cross-section Device or apparatus 10 is seen to have a distensible bladder or balloon 40 (shown here in a semi-inflated state) mounted to catheter 20 Catheter 20 is seen to have proximal end 21, proximal opening 22 longitudinal passage or lumen 25 , distal end 27, distal opening 28, interior surface 30 and exterior surface 32 It is preferred that catheter 20 be a multi-lumen catheter,

25 for example three lumens, although not required A second lumen 35 is used for electrical power leads 90, and a third lumen 37 is used for thermocouple leads 95 Mounted to the proximal end 21 of catheter 21 is the handle member 50 having interior passage 55, distal end 51 with distal opening 53 and proximal end 54 with proximal opening port 52 A fluid fill source 100 is shown but, in the depiction has not yet been mounted to opening 55 in handle 50 to actuate the inflation of balloon 40 with the required amount of fluid Mounted in the passage 55 of handle 50 is the valve 60 Valve 60 is seen to have closure member 62, stem 64 and exterior control handle 65 The fluid fill source 100 is seen to be a conventional syringe having plunger 102, body 104 and distal end 106 having opening 107 Although the lumen 25 of the catheter 20 may be in direct fluid contact with the interior passage 55 of handle 50, alternatively a handle tube 56 having a lumen 57 may be mounted in handle 50, wherein the lumen 57 and lumen 25 are in fluid communication. A Y- connector 58 having interior lumen 59 may be mounted to the proximal end of handle tube 56 wherin lumen 59 is in fluid communication with ports 52 and 90 As mentioned previously, the balloon 40 is mounted to the distal end 27 of catheter 20 Balloon member 40 is an inflatable bladder which is designed to make close contact with the endometrium when inflated with liquid during the tissue ablation process Balloon 40 is seen to have membrane 42, proximal end 43, proximal opening 44, interior 47, surface 49, and distal end 45

The balloon 40 must be capable of withstanding high temperatures without rupturing, an preferably have as good a heat transfer characteristic as is obtainable in such materials to provide efficient heating action. A distensible balloon of a heat curing rubber, such as latex rubber has been found to be satisfactory The inflation fluid 5 is preferably a sterile, biocompatible fluid, particularly preferred is a liquid. A five percent dextrose in water solution has been found to be effective The catheter 20 is made of a semi-flexible, flexible or rigid material which is heat resistant and biocompatible An example of a preferred material is a semi-flexible acrylonitrile-butadiene-styrene (ABS) polymer material, also polyurethane. As seen in FIGS 1. 1A, 2 and 3, a heating element 120 for the apparatus 10 of the present invention is illustrated In a particularly preferred embodiment of the present invention, the heating element 120 is located in the distal end of catheter 20, within lumen 25, proximal to the balloon 40 Heating element 120 is seen to have proximal end 121, distal end 122, and coils 125 Heating element is 120 is preferably a helix formed from resistive wire having a longitudinal passage 127 Heating element 120 may be mounted in lumen 25 so that water flows through passage 127 and thereby heats water to the desired temperature prior to entering balloon member 40 In this instance the heating element 120 shown consists of a resistance heating wire , although other heating means such as induction heating, using thermistors, RF heating devices that only heat the liquid flowing between the RF electrodes and do not themselves heat to temperatures much above the surrounding fluid, and others could function in the same way As balloon member 40 is filled with hot fluid, the balloon 40 expands until all endometrial surfaces are in close contact with the balloon membrane surface 48 As soon as the fluid in the balloon 40 has reached the predetermined pressure necessary to make such close contact, as measured by the control unit 200 and displayed by one of the display units 210, the fluid fill valve 60 is closed and the plunger 102 of fill unit 100 is released During the filling process the temperature of the fluid 5 within the balloon 40 is raised from essentially room temperature to between 85 °C and 100 °C. After the exposure time necessary to effect necrosis of the endometrium has elapsed, the balloon 40 is deflated by releasing the fluid fill valve 60 and letting the fluid 5 return into the fluid source 100. The fluid fill source 100, shown here as a syringe may be any other means of supplying fluid under gentle pressure. The electrical cable 160, between the control unit 200 and the catheter handle 50, is removably connected at port 80 The fluid hose 140 originating in the control unit 200 is connected to the catheter handle 50 at port 90 The distal end of hose 140 extends into passage 55 through port 90 Hose 140 is sealed and preferably contains air. Hose 140 is mounted at proximal end 145 into control unit 200 and is in fluid communication with a conventional pressure transducer contained therein. If desired a conventional pressure transducer may be mounted in port 90, and electrically connected to control unit 200 eliminating the need for hose 140.

FIG. 3 shows the ablation device 10 of the present invention having the distensible balloon 40 in an expanded position within the uterus 400. The balloon 40 is filled with fluid 5, which, preferably, is a physiologically compatible solution such as isotonic saline or a dextrose solution. The heating element 120 is located at the distal end 27 of catheter 20 , within the area of the cervix 405 and does not project into the distensible balloon 40. The catheter 20 may optionally have markings 29 as seen in FIG. 2 to aid in determining the depth of insertion of the balloon 40 into uterus 400.

Fig. 4a shows another embodiment of the apparatus of the present invention in which heating element 20 positioned in the distal end of the catheter 20. The heating element 120 functions differently from the embodiment shown in Fig. 2. The heater 120 in Fig. 2 is designed to heat the fluid 5 as it enters into the bladder 40 to distend it. This requires that the temperature of the liquid exiting the distal end 122 of the heater 120 be at or near 100 °C from beginning to the end of the fluid insufflation period. In contrast, located in the distal end 27 of catheter 20 adjacent to the heater 120 , shown in Fig. 4a, is an agitator 620 for recirculating the fluid through the heater as the treatment time goes on. A flexible thermocouple 600, whose actual location may vary, measures the temperature of the fluid 420 within the balloon 40, and the control unit 200 displays the temperature in a display window 210 and controls the heater 120 to ensure that a sufficiently high temperature is maintained during the treatment period. An agitator 620 which is also controlled from the control unit 200, is designed to pull liquid 5 from the distended bladder 40 through inner lumen 25. The coiled heating wire 120 is wrapped around concentric tubular member 630 within the lumen 25 of the catheter 20 . As the liquid 5 passes through the inner lumen 639 of tube 630 it is heated and expelled into the lumen 25 and returned to the balloon 40 via the lumen 25 where it attains its final temperature. The conventional valving arrangement 640 prevents the fluid from returning into the proximal sections of the catheter 20. The direction of fluid flow is indicated by the arrows within the drawing. The agitator 620 may be an impeller similar to the ones shown in US Patent Nos. 5,571, 153 or 5,704,934 or it may be of special design or be an ultrasonic device such as shown in US 5,460,628. Alternate devices capable of forcing the liquid to circulate will also be effective.

The impeller 620 is driven by a rotating flexible shaft 624 controlled from the control unit 200.

Fig 4b shows a cross-sectional view of an alternate design for effecting circulation around a heating element 120 contained within the catheter 20. The design differs from the embodiment shown in Fig. 4a in that the impeller 650 used to circulate the fluid 5 is located at the proximal end 121 of the heating element 120. Fluid 5 is drawn into the inner lumen 639 by impeller 650 which is so designed that it draws the fluid 5 in from the balloon 40 and discharges it again in the direction of the balloon 40 through the lumen 25 as indicated by the arrows in the drawing. The drawing also shows four support struts 655 which serve to keep the heating element 120 with its heating wires 670 centered in the main lumen 25 of the catheter 20. This impeller 650 may be of different designs, as long as it performs the required functions of pumping or moving fluid. In this Figure, the impeller 650 is shown as being driven by a flexible shaft 654 however, other means of driving the impeller

650 are quite feasible. The heating element 120 may be lengthened in order to achieve greater residence time of the recirculating fluid 5 in the heated zone. As seen in FIGS 5A and5B, an apparatus 800 of the present invention having a heating element 820 that is located in the proximal end 852 of the cannula 850 outside of the uterus 400, just past the cervical os and is located within the vagina. In the previously discussed embodiments, shown in FIGS 4a and 4b, the heating element 120 is designed to be as narrow as possible This precludes large heaters, which are generally more robust In the embodiment shown in Fig. 5, the heating element 820 is different from the previous heating elements 120 in that a heavy duty heating element can be used because extra space has been provided by means of an enlarged second lumen 839 The heating element 820 may consist of an extra heavy resistance wire wound around a portion of the catheter as is shown

Alternately it may be a rod type heater or any other type of heater which may require the extra space this design provides The heater need not be wound around the catheter, it can be free standing within the extra space Said space is provided by a second, enlarged lumen 839 which begins at a point just below said heating element 30 and tapers down to a smaller lumen just above the heating element The narrower portion of the second lumen continues through the length of the cervix 401 and opens into the balloon 840 The size of the outer lumen is reduced in the area of the cervix 401 to allow it to fit readily through the cervical area Fluid 5 may be circulated and heated using a valve arrangement as illustrated in FIG 5B having valve 880, valve seat 882 and recirculation openings 885 connecting the inner and outer lumens Locating the heater and circulating devices outside the cervix has the advantage that larger, more robust heating elements are possible to be used The use of more robust heaters would allow their repeated use, thus enabling the re-use, after sterilization, of the catheter 820 and catheter handle 890

The apparatuses of the present invention having heating elements proximal to the balloon 40, allow for the re-use of the device using removable attached disposable balloons As seen in Fig 6, a detachable balloon 40 is illustrated adjacent to a catheter 20 The distal end 27 of the catheter 20 is fitted with external screw threads 33 and the proximal end 43 of balloon 40 is seen to be mounted to a conventional socket member 900 containing female threads 910, which is attachable to the screw threads on distal end 27 of the catheter 20 It will be appreciated by those skilled in the art that member 900 may have external threads which mount to internal threads on distal end 27 Other conventional methods of attachment of balloon 40 to catheter 20, such as a compression fit using mechanical compression rings or mating mechanical interlocks, will be apparent to those skilled in the art Having attachable balloons is useful in a re-usable apparatus of the present invention After use of the device for endometrial ablation, the balloon itself is discarded and the remaining device saved to be sterilized After sterilization a new balloon 40 is screwed onto the catheter 20, and the device 10 is immediately ready for re-use An advantage of using a removable balloon 40 is that since the human uterus varies in size, a variety of different sizes of balloons 40 may be made available to the physician and a properly sized balloon can then be selected and attached to the catheter 20 for use in the procedure

Another embodiment of the catheters of the present invention is illustrated in FIG 7 which shows apparatus 910 having catheter 20 and handle 50 Heater 920 is mounted in passage 55 of handle 50 Balloon 40 is mounted to the distal end 27 of catheter 920 The device is similar in other respects to the embodiment illustrated in FIG 2, except that heater 920 is located in the passage 55 of handle 50

The following example is illustrative of the principles and practice of the present invention, although not limited thereto Example

The cauterization procedure is preceded by screening against cancer of the affected region and physical condition within established norms A PAP smear and endrometrial biopsy/curettage must exclude cancer or precancerous lesions of the uterus and cervix If a fibroid uterus is present, an ultrasound should exclude ovarian masses The uterine cavity must be 10 cm or less in length to be suitable for the small distensible bladder size

It would be preferable if the patient should be post menstrual or start on Danazol, or the equivalent which causes reduction in bleeding and a thin endometrium, at a rate of 800 ml daily, from the 5^th day of the previous menstrual period until two weeks after the procedure However, the above-mentioned is not a requirement She will undergo the procedure in the ambulatory surgery unit or outpatient facility where Valium and/or Demerol can be given intravenously if there is pain during the heating phase of the procedure

The apparatus of the present invention having a heater in the catheter distal to the balloon will be inserted after a bimanual examination and speculum of the cervix Dilation to 6 mm may be required which may necessitate a local 1% lidocaine block of the cervix Once in place the apparatus catheter protrudes from the vagina and consists of an electrical connecting plug, pressure line, syringe fill port, and rigid tubing Placement of the apparatus may be facilitated by distance markings on the rigid tubing indicating depth of insertion Upon placement of the apparatus it will be connected to a control unit via attachment of the electrical connector and flexible tubing attached to the handle to their receptacles on the control unit

Subsequent to insertion of the apparatus, the control unit will be powered on

The temperature of the fluid in the bladder will be preset to 87 degrees Celsius by the control unit and can be measured via the thermocouple located within the bladder Fluid pressure constraints are preset and upon inflation of the distensible bladder by introduction of fluid to the fluid system by depressing the plunger on the hypodermic barrel, can be easily measured by looking at the pressure display located on the control unit

The practitioner then process to inflate the distensible bladder by the plunger on the hypodermic barrel which may serve as the fluid source after powering up the heater in the catheter to heat the fluid to a preset temperature The practitioner injects the fluid into the fluid system until the control unit display indicates that the fluid pressure is within the preset constraints The volume required to fill the distensible bladder is about 30 cc in most cases in order to reach the pressure wherein the bladder is substantially in contact with all of the endometrium

The heating element in the catheter is connected via the plug to bring the fluid in the balloon to a temperature of about 87 degrees Celsius A circulator in the catheter circulates fluid between the heating element and the balloon Once that temperature level is reached, the system timer is activated to time the procedure and provide automatic turn off of the heating element at the end of a preset period

Upon completion of the procedure, the pressure valve and plunger are depressed to allow the fluid to be withdrawn from the fluid system causing the distensible balloon to deflate Upon deflation of the distensible balloon, the apparatus may be safely withdrawn from the patient

Although this invention has been shown and described with respect to detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention

Claims

We claim:

1 A uterine balloon treatment apparatus, comprising:

a catheter having a longitudinal internal passage, a distal end and a proximal end,

an inflatable balloon mounted to the distal end of the catheter, said inflatable balloon having an interior, wherein the interior of the inflatable member is in fluid communication with the internal passage of the catheter, and a proximal end with a proximal opening and a distal end;

a handle having a hollow, longitudinal passage mounted to the proximal end of the catheter;

a connector mounted to the handle for connecting the passage of the catheter to a source of liquid;

a heating element mounted in the internal passage of the catheter such that when said heating element is connected to a source of electrical power it generates heat, wherein the heater is positioned in the catheter distal to the balloon; and,

an electrical conductor mounted in the apparatus for providing electrical power to the heating element.

2. The apparatus of claim 1 additionally comprising a thermocouple mounted in the interior of the balloon.

3 The apparatus of claim 1 wherein the heater comprises a resistive wire

4 The apparatus of claim 1 wherein the heater comprises a thermistor.

5 The apparatus of claim 1 wherein the handle comprises a port for receiving wires

6 The apparatus of claim 1 wherein the handle additionally comprises a port for receiving a pressure transducer

7 The apparatus of claim 1 wherein the proximal end of the balloon is removably attached to the catheter

8 The apparatus of claim 7 wherein the distal end of the catheter comprises screw threads and the proximal end of the balloon comprises mating screw threads

9 The apparatus of claim 7, wherein the balloon is mounted to the catheter with a clamp

10 The apparatus of claim 1, wherein the catheter comprises at least two lumens

11. A uterine balloon treatment apparatus, comprising:

a catheter having a longitudinal internal lumen, a distal end and a proximal end. an inflatable balloon mounted to the distal end of the catheter, said inflatable balloon having an interior, wherein the interior of the inflatable member is in fluid communication with the internal passage of the catheter, and a proximal end with a proximal opening and a distal end,

a handle having a hollow longitudinal passage, said handle mounted to the proximal end of the catheter such that the interior passage of the handle is in fluid communication with the interior passage of the catheter,

a connector mounted to the handle for connecting the passage of the catheter to a source of liquid,

a heating element mounted in the interior passage of the handle such that when said heating element is connected to a source of elect╧Çcal power it generates heat, and,

an electrical conductor mounted in the apparatus for providing electrical power to the heating element

12 The apparatus of claim 1 1 additionally comprising a thermocouple mounted in the interior of the balloon

13 The apparatus of claim 1 1 wherein the heater comprises a resistive wire

14 The apparatus of claim 1 1 wherein the heater comprises a thermistor

15 The apparatus of claim 11 wherein the handle comprises a port for receiving wires

16 The apparatus of claim 1 1 wherein the handle additionally compromises a port for receiving a pressure transducer

5 17 The apparatus of claim 1 1 wherein the proximal end of the balloon is removably attached to the catheter

18 The apparatus of claim 17 wherein the distal end of the catheter comprises screw thread and the proximal end of the balloon comprises mating screw threads x ╧à

19 The apparatus of claim 18 wherein the balloon is mounted to the catheter with a clamp.

20 The apparatus of claim 11, wherein the catheter comprises at least two 15 lumens

21 The apparatus of claim 1 additionally comprising a control means connected to the handle to control temperature and pressure within the balloon

20 22 The apparatus of claim 1 additionally comprising a control means connected to the handle to control temperature and pressure within the balloon

23 A method of ablating endometrial tissue from the interior of a uterus comprising the steps of

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A providing an endometrial ablation apparatus comprising. a catheter having a longitudinal internal passage, a distal end and a proximal end,

an inflatable balloon mounted to the distal end of the catheter, said inflatable balloon having an interior, wherein the interior of the inflatable member is in fluid communication with the internal passage of the catheter, and a proximal end with a proximal opening and a distal end,

a handle having a hollow, longitudinal passage mounted to the proximal end of the catheter.

a heating element mounted in the internal passage of the catheter such that when said heating element is connected to a source of electrical power it generates heat, wherein the heater is positioned in the catheter distal to the balloon, and,

an electrical conductor mounted in the apparatus for providing electrical power to the heating element,

B inserting the balloon and distal end of the catheter into a uterus having an endometrial layer, and,

C heating the endometrial layer to a sufficient temperature for a sufficient length of time to effectively ablate the layer

24. A method of ablating endometrial tissue from the interior of a uterus comprising the steps of:

A. providing an endometrial ablation apparatus comprising: a catheter having a longitudinal internal lumen, a distal end and a proximal end;

a handle having a hollow longitudinal passage, said handle mounted to the proximal end of the catheter such that the interior passage of the handle is in fluid communication with the interior passage of the catheter;

a heating element mounted in the interior passage of the handle such that when said heating element is connected to a source of electrical power it generates heat; and,

B. inserting the balloon and distal end of the catheter into a uterus having an endometrial layer; and, C heating the endometrial layer to a sufficient temperature for a sufficient length of time to effectively ablate the layer_.