ENDOMETRIAL ABLATION METHOD AND APPARATUS

Abstract: An apparatus and method for effecting necrosis of a tissue lining of uterine endometrium, by introducing an applicator comprising a distendable bladder (7) and catheter. The bladder (7) is pre-shaped to approximate the bicornual shape of the uterus and is manufactured from bio-compatible, non-allergenic specification quality material. There are two pre-shaped sizes; one for nulliparous uteri and one for parous uteri. The bladder (7) is connected to a catheter that contains a non-metallic spring method to ensure the proper deployment and shaping of the bladder. The bladder (7) is then distended by introducing a heated, by means external to the bladder and catheter, (above 220 DEG F) bio-compatible fluid under pressure (40 - 150 mm Hg) for a period of 30 - 90 seconds and then a repeat procedure of 30 - 90 seconds. The regulation of said apparatus is by means located external to the uterus, and ensures thermal ablation of substantially the entire tissue lining of the endometrium.

Description: Endometrial Ablation Method and Apparatus FIELD OF THE INVENTION The present invention relates to an apparatus and method for thermally ablating the endometrial tissue lining the uterine cavity. More specifically, the apparatus and method of the present invention uses a pre-shaped balloon and ensures proper deployment of the balloon, through mechanical means, to conform to the shape of the uterus. In addition the method of thermal ablation is significantly changed when compared to known intrauterine thermal ablation techniques. BACKGROUND OF THE INVENTION A tissue ablator is a device used to cauterize, or induce necrosis, of living tissue. Intrauterine tissue ablators are useful for treating menorrhagia and metrorrhagia, excessive bleeding conditions sometimes associated with pain. Ablation is usually accomplished by thermal or cryogenic treatments. One thermal treatment involves treatment of the tissue with a laser or electro-cautery device. A physician using this procedure for uterine ablation must "paint" the intrauterine surface with the laser beam or electro-cautery probe, making it difficult to uniformly treat the entire intrauterine area. Incomplete treatment can result in continued bleeding discomfort. Also inherent in the laser or electro-cautery techniques is the risk that an area of the tissue surface will be punctured from the prolonged exposure to the beam or probe. Another method for tissue ablation involves an inflatable bladder which is inserted into the organ and inflated with a thermal or cryogenic substance. The inflated bladder contacts the surrounding tissue and the extreme temperature of the thermal or cryogenic substance in the balloon causes the tissue to necrose. One such device intended for intrauterine cauterization is disclosed in U.S. Pat. No.'s 4,949,718 and 5,105,808. An inflatable bladder located at the end of a catheter is inserted into the uterus. A liquid medium is used to fill the bladder, causing it to inflate inside the uterus. Heating coils located inside the bladder heat the medium to temperatures of 140° F to 215° F (temperatures known to induce necrosis of endometrial lining) for a period of 4-12 minutes. This device suffers from the disadvantage of using a substantially spherical bladder, whereas the uterus is bicornate in shape. This introduces the potential for leaving areas untreated. The long treatment time can increase patient and physician discomfort. Moreover, the heating element is located inside the body during treatment. The heating coil reaches temperatures much higher than the fluid temperature and its placement in the bladder creates the risk that the patient may be burned. The heating and temperature probe are located centrally and remote from the endometrial lining resulting in temperatures at the lining are less than at the probe by unknown amounts. Another thermal ablation device intended for intrauterine cauterization is disclosed in U.S. Pat. No. 5,449,380. An inflatable bladder located at the end of a catheter is inserted into the uterus. The device contains an inflation means for circulating an inflation fluid through the catheter and the balloon, and a heating means for heating the inflation fluid to temperatures of 190° F to 220° F. The balloon is mechanically shaped to approximate the shape of the organ. This device suffers from the disadvantage of lack of control of heat transfer to the tissue to be necrosed due to a single sized spherical bladder being forced to take the shape of the uterus in 2 dimensions only. Moreover introducing a circulating fluid where temperature is controlled outside the bladder introduces opportunities for fluid short-circuits, improper mixing, potential dead zones where fluid temperatures are not sufficient to effectively ablate tissue and non uniform heating leading to untreated areas. Another thermal ablation device intended for endometrial ablation is disclosed U.S. Pat. No. 5,084,044. A thermally conductive inflatable member is inserted into the uterus. The inflatable member is filled with fluid that could be heated prior to, during passage to the inflatable member or once inside the inflatable member. The inflation fluid is heated to temperatures of about 122° F to 21 1° F and is claimed to urge the inflatable member into the expanded position and into intimate contact with the tissue of the cavity. A predetermined time for treatment is selected to be in the range between 30 seconds and 10 minutes. This device suffers from the disadvantage of using an inflatable means that is not preformed to the shape of the uterus which is bicornate in shape. This introduces the potential for leaving areas untreated. SUMMARY OF THE INVENTION The present invention thermally ablates tissue by introducing heated fluid through pre- shaped balloon which is inserted into the uterus on the tip of a catheter. The pre-shape is designed for two sizes nulliparuos and parous. In addition the balloon is mechanically deployed in a 3 dimensional fashion to ensure the conforming of the pre-shaped balloon to the uterus and effectively treating the entire uterus. In addition the method of thermal ablation utilizes higher temperatures, (above 220° F), than previously used in prior art and for a shorter period of time. Furthermore the treatment is performed twice to provide for even greater efficacy of the ablation technique. The present invention provides advantages over prior art to achieve more uniform and complete endometrial lining contact at monitored, higher temperatures for a more efficacious thermal ablation treatment. Specifically the accumulative advantages are provided by: a) Provision of two balloon sizes - one for nulliparous and one for parous uteri. b) Pre-shaped balloons conforming to the actual bicornate and shallow depth of the uterus. c) Positional indicators to assure proper insertion. d) An optional mechanically aided 3-D deployment of the balloon. f) Higher than previous art temperatures - at known and uniform values. e) Shorter than previous art treatment times with superior ergonometrics to ease physician stress. g) Dual treatment procedure to take advantage of improved necrosis of the endometrial lining. h) Use of biocompatible, non-allergenic material for balloon construction. In addition, the front end reusable equipment has been designed to provide improved variable control at low costs to the end user. DESCRIPTION OF THE DRAWINGS FIG. 1 is a 3-dimensional view of the inside of the uterus showing a pre-formed 3- dimensionally mechanically shaped balloon according to the present invention. FIG. 2 is a schematic for the entire endometrial ablation apparatus. FIG. 3 is a horizontal and frontal plane view of the endometrial ablator part (II) without the optional retractable sleeve. DETAILED DESCRIPTION Referring to figure 2, the heater/injector part (1) contains: a variable capacity chamber (2) that provides reliable temperature pressure monitoring, vapor venting, vapor separation, and sufficient volume to prevent temperature decline through heat loss; a built-in temperature/pressure display (1) to provide a display Tl-2 of temperature of the hot liquid - (The liquid will be solutions that will allow liquid temperatures in excess of 220° F without risk of boiling. Examples of such solutions are mixtures of n-Butyl alcohol or similar even-numbered Carbon, non-toxic alcohols, glycerol, glycerol/water mixtures, and mineral oil) - in the endometrial ablator part (II) via a thermocouple located inside the balloon (7). In addition, pressure PI and temperature Tl-1 inside the heater/injector part (I) is monitored; a pressure injection module (4) ergonometrically designed to provide easy and efficient control of liquid injection into the balloon, pressure regulation and liquid withdrawal from the balloon; a liquid capacity chamber (5) of sufficient volume to assure deliverance of up to 100 ml of temperature controlled liquid to the balloon for a dual ablation procedure; a specification standard immersion heater(s) or specification standard band heater(s) (3) fitted into or around the liquid heater/container (5) and is equipped with a regulator for temperature control connected by a standard cord plugged into a standard 1 10 V/ 60 cycle outlet and; stopcock valves for liquid charging, venting, draining and control of liquid movements into and out of the balloon, plus quick connect coupling to avoid introduction of air to purged part (II). Referring to figure 2, an endometrial ablator part (II) according to the present invention is comprised of : a pre-shaped inflatable balloon (7) which is sealed around the distal end of a catheter - (The balloon material is: flexible (softness, strength, workability similar to Latex) and; chemically resistant to n-Butyl alcohol or similar even-numbered Carbon, non-toxic alcohols, non-toxic alcohol-Glycerol solutions, non-toxic glycerol-water solutions, non-toxic mineral oil solutions at temperatures greater than 220° F; compatible -5- SUBSTl fUTE SHEET (RULE 26) with molding techniques; compatible with non-toxic, biocompatible coatings to prevent sticking to uterine cavities.); a catheter that delivers inflation liquid and couples as a position indicator (8) for both balloon depth and rotational orientation; an optional retractable sleeve (6) providing - a pre-sheathing of the balloon for ease of part (II) delivery, a restraint for an optional solid mechanical 3-dimensional balloon deployer (9) with positional memory and, an insulation shield to protect the cervix, cervical glands and uterus; an optional 3-dimensional mechanical balloon deployer (9) that provides assurance that the balloon will properly deploy within the uterine chamber and conform to the shape of the uterus - (The optional mechanical balloon deployer is manufactured of appropriate material that is non-toxic and super-elastic and strong enough to reliably deploy the pre-shaped balloon inside the uterine chamber. In addition the mechanical balloon deployer will allow easy withdrawal of the endometrial ablator part (II) post treatment.) - and; a standard quick connect coupling at the distal end to allow for quick connection to part (I). Use of the preferred embodiment will next be described. STEP 1 : Standard pre-sizing of uterus determines depth that device will be inserted. STEP 2: Charge liquid to part (II,) with valve to part (I) closed. STEP 3: Heat liquid in the liquid/container (5) via the immersion heater (3) to desired temperature (> 220° F). STEP 4: Air is purged from part (II) by partially filling the system with saline solution. This partial filling is performed prior to insertion of the device into the uterus, with the retractable sleeve (6)(if applicable) held in the distal position to prevent the balloon from inflating. STEP 5: Connect part (I) to part (II). STEP 6: Insert part (II) into uterus using position indicator (8) to ensure proper depth and rotational orientation of the pre-shaped balloon. STEP 7: Pull back retractable sleeve (if applicable) (6). STEP 8: Start timing and flush hot inflation liquid into part (II) for 30 - 90 seconds. STEP 9: Monitor balloon temperature and when temperature is below 220 °F, withdraw inflation liquid from part (II). STEP 10: Repeat STEPS 8 and 9. STEP 1 1 : Drain liquid into disposable liquid container, or if part (I) is disposable discard part (I) and part (II). If part (II) is not disposable disconnect after draining and discard part (II).

Claims: CONCLUSION The present invention is described in relation to the preferred embodiment but is limited only in terms of the language of the applied claims. What is claimed: 1. An apparatus for thermally ablating tissue in a uterus, comprising: (a) a catheter having a proximal end and a distal end; (b) two-sizes of pre-shaped inflatable balloons, (for parous and nulliparous uteri) individually attached to the distal end of the catheter which will conform to the shape of the uterus; (c) a balloon deployment system connected to the distal end of the catheter that is deployed via mechanical and/or hydraulic means that in turn engages the balloon and deploys the pre-shaped balloon; (d) a balloon inflation means for pushing inflation fluid through the capacitive element, the catheter and into the balloon; (e) a balloon deflation means for withdrawing inflation fluid from the balloon, the catheter and from the capacitive element; (f) a heating means for heating the inflation fluid to an elevated temperature of >220 °F, and; (g) a capacity chamber to provide a capacitive element allowing reliable pressure monitoring, vapor venting, vapor separation and sufficient volume to prevent temperature decline through heat loss; 2. The apparatus of claim 1 wherein the catheter has a longitudinal axis and wherein optional mechanical balloon deployment members have two positions - a contracted position in which the deployment members are substantially parallel to the longitudinal axis and an extended position in which the primary deployment members extends in a plane perpendicular from the catheter and attached at the end of the primary deployment, a secondary deployment member that provides member extension above and below the plane of the catheter/primary deployment member - thereby ensuring proper balloon deployment and conformation to the inside of the uterine cavity; 3. The apparatus in claim 1 further comprising: a restraining means for holding the optional primary and secondary deployment members in a contracted position and; a releasing means for releasing the optional primary and secondary deployment members for movement from the contracted to the extended position; 4. The apparatus of claim 1 wherein the restraining means and the releasing means of the optional primary and secondary deployment members are further comprised of an optional retractable sleeve around the catheter, the optional retractable sleeve mounted in a longitudinal direction and having two positions: a distal position wherein the sleeve covers the balloon and the optional deployment members in their contracted position and; a proximal position wherein the sleeve is retracted to a position proximal to the balloon and optional deployment members thus releasing the optional primary and secondary deployment members into their extended position; 5. The apparatus of claim 1 further comprising a pressure injection part that contains two main components: inflation and deflation triggers that are ergonometrically designed to allow for easy operator use to control balloon inflation and deflation and easily maintain and monitor balloon pressure; capacitive reservoir in a housing that has an optional easy to view volume monitoring window; 6. The apparatus of claim 1 further comprising a variable/capacity chamber that provides means to regulate and monitor pressure and temperature of heated fluid and further provides a closed hydraulic system to reliably transfer pressures to ensure balloon filling and emptying. 7. The apparatus of claim 1 that incorporates major design simplifications whilst maintaining efficiency to reduce apparatus cost significantly and making the procedure more adaptable to doctors office, clinics and remote or isolated settings. 8. The apparatus of claim 1 that provides for unique 100% recycle and reuse of component parts allowing to resolve environmental concerns.

Inventors: ELLIOTT JAMES, LUO QIYI, YACKEL DOUGLASS, ELLIOTT, JAMES, LUO, QIYI, YACKEL, DOUGLASS
Applicants: ELLIOTT JAMES, LUO QIYI, YACKEL DOUGLASS, ELLIOTT, JAMES, LUO, QIYI, YACKEL, DOUGLASS
Application year: 1999
Main classification: A61F7
IPC codes: A61B17, A61B18, A61F7