Intrauterine cauterizing apparatus

Abstract: A method and apparatus for effecting necrosis of a tissue lining of a mammalian body cavity, particularly a uterine endometrium (27), by introducing an applicator comprising a distendable bladder (5) connected to a catheter into the uterus, distending the bladder (5) by introducing a non-toxic fluid under pressure, heating the fluid by means (44) located internal to the bladder (5) to a temperature of 190° to 215°F and preferably 210°F for a period of 4 to 12 minutes and preferably 6 minutes and regulating said apparatus by means (30) located external to the uterus, thereby cauterizing substantially the entirety of the tissue lining, particularly the endometrium (27).

Description: This invention relates to an applicator for thermal cauterization of substantially all of the human uterine endometrium. More specifically, the applicator ensures effective cauterization of the human uterine endometrium without many of the disadvantages and dangerous features of known intrauterine cauterization techniques. The following terms as used herein have the meaning given below: "Necrosis" means the death of cells in tissue. "Endometrium" is that portion of the inner lining of the uterus to which an embryo normally attaches and excludes the portions of the uterine inner lining forming the cervix, to which the embryo usually does not attach. Apparatus and methods for cauterization of the endometrium of a uterus, useful in sterilization procedures and cancer treatments, are well known. Thermal and cryogenic treatments have been utilized in such cauterization techniques and typically involve either the direct or indirect application of heat or cold to the tissue to be treated. For example, a laser hysteroscope has been used to cauterize the endometrial layer of the uterus. This laser treatment suffers from several disadvantages. It requires the application of an intense amount of thermal energy to a relatively small area of tissue even though such a large amount of heat may not be necessary to effectively cauterize the tissue. Further, this laser treatment requires the physician to continually reposition the laser used in the treatment within the uterus in order to treat the entire endometrium. Such internal manipulation of a laser hysteroscope within the uterus of a patient is both difficult, requiring a significant level of skill to perform, and potentially dangerous. Accidental puncture of the uterine or tissue wall may result from manipulation of the laser scope within the uterus or body cavity, and tissue layers beneath the endometrium may be burned if a laser's beam is left focused on one area of tissue for too long a period of time. A variety of alternatives to laser treatment in cauterizing the uterine endometrium are known. In U.S. Patent No. 3,924,628, Droegemueller et al. disclose a method and apparatus for necrosing tissue cells that utilizes an extendable bladder which is inserted in the uterus and filled with a circulating fluid or gas at cryogenic temperatures (referring to temperatures sufficiently low to cause cell necrosis). The bladder disclosed by Droegemueller et al. is maintained in substantially continuous contact with the inner surface of the uterine lining and achieves necrosis of substantially all of the uterine endometrium in a single treatment. Droegemueller et al. disclose the use of liquid nitrogen that vaporizes prior to introduction into the bladder, thereby pressurizing the bladder to a level which ensures adequate contact with the uterus. Other fluids disclosed by Droegemueller et al. as useful in their method include refrigerants such as freon. Droegemueller et al.'s method and apparatus suffers from the disadvantage of employing cryogenic fluids which could prove toxic to a patient in the event of bladder rupture. Moreover, Droegemueller et al.'s apparatus does not allow regulating the pressure used to inflate the bladder. Another disadvantage of Droegemueller et al.'s technique is that cryogenic necrosis of the endometrium occurs at extremely low temperatures that pose a threat to tissue layers adjacent to the uterine endometrium. Droegemueller et al. and similar cryogenic techniques also require the use of expensive equipment such as compressors and insulated vessels associated with the storage and transmission of refrigerants. Moreover, Droegemueller et al.'s technique may require warming of the bladder in order to remove it from the body and minimize tearing of the surrounding tissue which has adhered to the bladder during the freezing process. In U.S. Patent No. 2,734,508, Kosinski discloses a therapeutic apparatus for applying dry heat to body cavities comprising an applicator that is introduced in the body cavity while deflated and which is subsequently inflated and heated by means of circulating hot air. Kozinski does not disclose an applicator which conforms to the shape of a body cavity. Further, given the lower heat transfer coefficients of gases as compared with liquid, treatment with Kozinski's apparatus should involve a long period of time in order to achieve necrosis, thereby exposing the patient to additional discomfort and risk. Moreover, Kozinski's apparatus does not provide for measurement and regulation of internal pressures and temperatures of the applicator introduced. U.S. Patent No. 2,077,453, issued to Albright, discloses a therapeutic appliance comprising a relatively long tubular applicator which is shaped and formed generally to the passage into which it is to be inserted and which has relatively thin elastic rubber walls that transfer heat and which distend to fit irregularities of the treated areas upon application of internal pressure. Albright also discloses that fluids such as heated water could be utilized as a heating means in his applicator. The applicator of Albright, like that of Kozinski, however, suffers from the disadvantage that the distension of its walls to conform to the irregularities of the endometrium is limited as Albright provides an integral rubber web which serves to prevent undue distension of the applicator. Moreover, Albright requires that the fluid be circulated throughout the apparatus. Albright also does not provide an apparatus that allows regulation of temperature and pressure of the fluid or other bladder inflation means. US-Patent No. 2 078 786, issued to Wood, describes an applicator device for applying dry heat to various cavities of the body for the purpose of creating hyperemic effects at any desired temperature, and while a dilating pressure is applied to the body cavity wall. The device as illustrated is designed for rectal and vaginal cork in view of its dimensions. However, it is stated that it is applicable also for treatment of ear, eye, nose, throat, palate, etc. The applicator as illustrated in Fig. 1 comprises a stiff insertion tube surrounded by an elastic insertion tube which is drawn over the stiff insertion tube and sealingly secured at the inner (distal) end. Inside the stiff insertion tube is a vent means for removing air from and admitting air to the applicator, a heating means, a temperature regulating system, a thermometer, and a tube which contains ether as an expansive element forming part of a thermostatic regulating system. U.S. Patent No. 3,369,549, issued to Armao, discloses a therapeutic device for applying heat or cold to body cavities comprising a capsule probe containing a heat exchanger and a flexible bladder that can be inflated to conform to a body cavity. Armao does not, however, disclose a control means for regulating the temperature and pressure of the flexible applicator, nor does he disclose cauterizing tissue in the cavity being treated. Other patents that disclose the use of thermal treatment of the interior lining of a body cavity include U.S. Patent Nos. 2,192,768; 2,466,042; 2,777,445; and 3,369,549. DE-A-3 725 691 describes a heat-curing apparatus for destroying attacked or diseased body tissue by means of heat, characterized by an endoscope with a probe for insertion into a body cavity and with a tweezers or forceps hole, a catheter whose distal end section can be inserted into the body cavity through the forceps hole of the endoscope and which has a fluid passage opening out at the distal end section, a contractible balloon (bladder) covering the distal end section of the catheter for receiving the fluid introduced via the fluid passage, the balloon being capable of being brought into contact with the attacked body tissue, and a heating element arranged at the distal end section of the catheter for heating the fluid contained in the balloon. The reference device actually is intended for treatment of stenoses of ducts, e.g. elimination of cancerous growths in a bile duct by relatively long term exposure of the cancerous tissue to a temperature that is high enough to destroy cancer cells but not so high as to destroy normal cells. The reference indicates that an appropriate temperature for this purpose is 43°C ±1°C for a time period of several days to several weeks. The reference device is flexible, without a rigid stem to form a proximal end portion. The reference device is intended for use with an endoscope and with a guide wire. Also, the heating element of the catheter is not fully enclosed within the balloon but is partially exposed (i.e. situated outside the enclosure defined by the balloon) so that the heating element can be used to heat water within the enclosure and to cauterize by direct contact with tissue. In the reference catheter, the proximal end is defined by the exposed heater and must be hollow, and with a through opening (a duct), in order to accommodate the necessary guide wire. The problem underlying the present intention is to provide a relatively inexpensive and easy to replace applicator for effecting rapid thermal cauterization of substantially all of the human uterine endometrium. The applicator of the present invention comprises: a catheter for insertion into the uterus via the cervical canal, said catheter terminating in a rigid, axially closed proximal end portion and having an open distal end, and a distendable bladder 5 defining an enclosure attached at said proximal end portion and projecting axially beyond the proximal end of the catheter when distended; said bladder 5 when distended contacts substantially all of the tissue lining of the uterus: inflating means 14 connected to said distal end for distending said bladder 5 with a fluid 25 from a fluid system; and heating means 44 for heating said fluid 25, said heating means being positioned internal to said bladder 5. Claims 2 to 13 relate to further embodiments of the applicator. Description of the drawings. Fig. 1 depicts an applicator of the present invention with a distendable bladder 5 which has been inserted into and inflated within a human uterus 6. Fig. 2 depicts placement of an applicator with the distendable bladder 5 within the human uterus. Fig. 3 is a view of an applicator that illustrates the applicator connections. Fig. 4 depicts a system control unit 30 for the applicator. Fig. 5 is a detail view of a pressure limiting and safety monitor for the applicator. Fig. 6A is the vented heating element shield 45 of the applicator. Fig. 6B is a cutaway view of the vented heating element shield 45 showing the heating element 47 and thermocouple 48 of the applicator. Fig. 7 depicts a means for connecting and disconnecting the applicator. Figure 1 shows an inflated distendable bladder 5 attached to rigid tubing 3 located within a human uterus 6. Inflation of the distendable bladder 5 with a fluid 25 assures uniform contact of the bladder with the endometrial tissue layer 27 of the uterus 6. The rigid tubing 3 and the attached bladder 5 must be sufficiently small, when the bladder is deflated, so that it can be conveniently and safely inserted into the uterus 6 through a partially dilated cervix 22. The rigid tubing with the deflated bladder is aligned with the cervical canal after the cervix is exposed with a speculum and grasped with a tenaculum. After the bladder 5 has been inserted, the bladder 5 should be inflated to a pressure sufficient to ensure firm contact with the tissue to be necrosed, in this case the endometrial tissue layer on the interior uterine surface but should preferably be maintained at or about 5.3 to 18.7 kPa (40 to 140 mmHg), and preferably about 10 kPa (75 mmHg), to minimize risk of rupture of the bladder 5 and possible internal injury to the patient. The bladder 5 must be capable of withstanding high temperatures without rupturing, and preferably have as good a heat transfer characteristic as is obtainable in such materials to provide efficient heating action. A bladder of a heat curing rubber such as latex rubber has been found satisfactory. Fluid 25 preferably should be a sterile non-toxic fluid with a boiling point of at least 100°C (212°F). A five percent dextrose in water solution has been found satisfactory. As illustrated in Figure 2, the uninflated bladder 5 attached to rigid tubing 3 is inserted into the vagina 21, past the cervical os 22, through the cervical canal 23, for placement in the uterine cavity 20. Placement may be aided by virtue of scale gradations 4 located on the rigid tubing 3 to indicate the depth of insertion of the bladder 5. Rigid tubing 3 is attached to a control unit 30 (shown in Fig. 3) via flexible tubing 10. Figure 3 depicts the arrangement of control unit 30 and applicator end 1, comprising the bladder 5, rigid tubing 3 and flexible tubing 10, and the interconnection of those elements. A fluid system comprises that portion of the apparatus through which the fluid 25 travels, including a hypodermic barrel 14 or other fluid source (not shown), flexible tubing 10, rigid tubing 3, bladder 5 and control unit 30. Manipulation of the hypodermic barrel 14 enables the operator of the system to control the amount of fluid 25 in the fluid system, inflation and deflation of the bladder 5 by adding or removing fluid, respectively, and pressure of the fluid 25 in the system. The hypodermic barrel 14 also provides protection for the patient by allowing fast and safe reduction of excessive pressures in the system that might build up through some malfunction. Manipulation of the hypodermic barrel 14 by depressing a plunger 60 causes fluid 25 to be introduced through a 3-way stopcock 12 into the flexible tubing 10, and to the rigid tubing 3. The fluid 25 emerges from rigid tubing 3 and into bladder 5, forcing the bladder 5 to expand into contact with the endometrial tissue layer 27 of the uterus 6. The fluid 25 is also directed along the flexible tubing to the control unit 30 allowing measurement of the fluid pressure within the bladder 5 by well known means. Each of the parts of the fluid system is in fluid communication providing constant fluid pressure within the entire fluid system and allowing measurement of the pressure at the applicator end 1 via measurement of pressure of the end attached to the control unit 30. Control unit 30 is connected to applicator end 1 via plastic sheath 15 which contains flexible tubing 10 and electrical sheath 16. Flexible tubing 10 is connected to a fluid joint 56 via pressure transducer 54, by well known means. Using a standard luer lock connector 19, pressure transducer 54 and hypodermic barrel 14 are connected to flexible tubing 10 via a readily available 3-way stopcock 12. The 3-way stopcock 12 may be used to isolate the hypodermic barrel 14 or other fluid source from the fluid system once the desired fluid pressure is reached. Figure 4 depicts the control unit 30, consisting of fluid temperature control 31, fluid pressure control 34, time control 38' and a power source (not shown). The control unit 30 includes a power switch 42 and fuse 41. Fluid temperature is regulated by fluid temperature control 31 and is set by temperature set/reset button 33. The temperature of fluid 25 in the bladder 5 is shown at temperature display 32. Fluid pressure within the fluid system is regulated by means of controls located on fluid pressure control panel 34. The upper limit for fluid pressure is controlled by high pressure set/reset button 35, with the lower limit controlled by low pressure set/reset button 36. Fluid pressure in mmHg is shown by LED pressure display 37. Control unit 30 also has pressure indicator display 43, which upon introduction of fluid 25 into the fluid system provides an easy to see visual display of fluid pressure within the fluid system. Time for the cauterization procedure is shown at time display 38, which displays both lapsed time and time remaining for the cauterization. Total time for the cauterization procedure may be easily set in minutes, seconds, and tenths of seconds using time set buttons 39 and may be cleared or reset using time clear/reset button 40. A simplified means for determining whether the fluid 25 is within the preset pressure range is depicted in Figure 5, which illustrates the pressure indicator display 43. The pressure indicator display 43 is comprised of a low pressure indicator 51, a high pressure indicator 52 and an optimum pressure indicator 53. As fluid 25 is introduced into the fluid system by manipulation of hypodermic barrel 14, the pressure indicator display 43 is successively illuminated as various fluid pressures are reached. Low pressure indicator 51 is illuminated when fluid pressure is below the preset range. High pressure indicator 52 is illuminated when fluid pressure is above the preset range. Optimum pressure indicator 53 is illuminated when fluid pressure is within the preset range. These indicators allow the practitioner to readily reach the preset pressure range by varying the amount of fluid in the fluid system via manipulation of the hypodermic barrel 14. A separate heating element indicator is also provided to indicate when power is being provided to heating element 44 located within the bladder 5. Two views of heating element 44 are shown in Figures 6A and 6B. Figure 6A is an external view of heating element 44, which comprises heating element shield 45 and ventilation holes 46. Figure 6B is a cutaway view of heating element 44, wherein wire leads 49 provide power from system control unit 30 to heating element coil 47 causing heating element coil 47 to heat the fluid 25 which comes into contact with the heating element coil 47 as the fluid 25 flows through the ventilation holes 46. Temperature of the fluid 25 is measured by thermocouple 48 and is displayed at temperature display 32. Heat element shield 45 prevents bladder 5 from contacting the heating element coil 47. The applicator end 1 is designed to be easy to replace as shown in Figure 7, which depicts control unit end 30 and applicator end 1 of the invention. Control unit end 30 is composed of electrical sheath 16 which is attached on one end to control unit 30 and on the other end to male electrical connector 24, which allows transmittal of power to the heating element 44. Male electrical connector 24 is readily attached or disattached to female electrical connector 17 on the applicator end 1. Control unit end 30 is also comprised of components from the fluid system, including flexible tubing 10 attached to the 3-way stopcock 12. The 3-way stopcock 12 provides control over the introduction and removal of fluid 25 via the hypodermic barrel 14. The applicator end 1 is easily connected or disconnected from the 3-way stopcock via a luer lock connector 19 attached to pressure transducer 54. The applicator of the present invention is used in a method for cauterizing substantially the entirety of the endometrium of a human uterus by application within an inflatable bladder of a fluid at a pressure of 5.3 to 18.7 kPa (40 to 140 mmHg) and preferably about 10 kPa (75 mmHg), heated to a temperature of 60°C to 102°C (140°F to 215°F) and preferably about 99°C (210°F) for a period of 4 to 12 minutes, with a preference of around 6 minutes, thereby realizing substantial necrosis of substantially all of the uterine endometrium without significant damage to surrounding tissue. Necrosis of the uterine endometrium may be achieved by insertion of the applicator comprising rigid and flexible tubing and a readily distendable high strength bladder material into the uterus; introduction of a fluid through the tubing into the distendable bladder at a pressure of 40 to 140 mmHg and preferably about 75 mmHg, thereby inflating the bladder so that it substantially conforms to the irregularities in the shape of the endometrium; the pressure of the fluid measured and regulated by means external to the uterus; heating the fluid to a temperature of 60°C to 102°C and preferably about 99°C for a period of 4 to 12 minutes, with a preference of around 6 minutes, by heating means positioned within the bladder and regulated by control means external to the applicator, thereby cauterizing substantially the entirety of the uterine endometrium. The use of the applicator of the present invention will now be illustrated by the following example. Example The cauterization procedure is preceded by screening against cancer of the affected region and physical condition within established norms. A PAP smear and endometrial biopsy/ curettage must exclude cancer or precancerous lesions of the uterus and cervix. If a fibroid uterus is present, an ultrasound examination should exclude ovarian masses. The uterine cavity must be 10 cm or less in length to be suitable for the small distendable bladder size. The patient should be post menstrual or start on Danazol R , or the equivalent which causes reduction in bleeding and a thin endometrium, at a rate of 800 ml daily, from the 5th day of the previous menstrual period until two weeks after the procedure. The patient will undergo the procedure in the ambulatory surgery unit or outpatient facility where Valium R and/or Demerol R can be given intravenously if there is pain during the heating phase of the procedure. The applicator 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 applicator stem protrudes from the vagina and consists of an electrical connecting plug and rigid tubing. Placement of the applicator may be facilitated by distance markings on the rigid tubing indicating depth of insertion. Upon placement of the applicator it will be connected to a control unit via attachment of the electrical connector and flexible tubing attached to the rigid tubing to their counterparts extending from the control unit. Subsequent to insertion of the applicator, the control unit will be powered on in order to allow the practitioner to set the system constraints. The temperature of the fluid in the bladder will be set at the temperature control panel and can be measured via the thermocouple located within the bladder. Fluid pressure constraints are set at the pressure control panel, and upon inflation of the 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 indicator lights located on the control unit. The practitioner then proceeds to inflate the bladder by rotating the lever on the 3-way stopcock in order to access the fluid source and depressing the plunger on the hypodermic barrel which may serve as the fluid source. The practitioner injects the fluid into the fluid system until the pressure indicator lights indicate that the fluid pressure is within the pre-set constraints. At that point, the practitioner manipulates the 3-way stopcock to close off access to the fluid system by the fluid remaining in the hypodermic barrel. Thus, the fluid is non-circulating during the heating portion of the cauterization procedure, in part allowing more precise measurement of fluid temperature. The volume of fluid necessary to inflate the bladder will vary from 3 to 20 ml in most cases in order to reach the pressure wherein the bladder is substantially in contact with all of the endometrium. The practitioner then turns on the heating element in order to heat the fluid to a pre-set level. The heating element in the bladder is connected via the plug to a 12 volt system which will bring the fluid in the bladder to the level of boiling as needed for each particular local, i.e. 87°C (190°F) in Mexico City, and 100°C (212°F) in New York City. 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 pre-set period. Upon completion of the procedure, the 3-way stopcock is again manipulated to allow the fluid to be withdrawn from the fluid system causing the bladder to deflate. Upon deflation of the bladder, the applicator may be safely withdrawn from the patient. The coagulated endometrium is then removed from the endometrial cavity with a curette, leaving the underlying surface free to form adhesions with the other opposing surfaces of the uterine cavity.

Claims: Applicator for effecting thermal cauterization of substantially all of the human uterine endometrium, comprising: a catheter for insertion into the uterus via the cervical canal, said catheter terminating in a rigid, axially closed proximal end portion and having an open distal end, and a distendable bladder (5) defining an enclosure attached at said proximal end portion and projecting axially beyond the proximal end of the catheter when distended; said bladder (5) when distended contacts substantially all of the tissue lining of the uterus: inflating means 14 connected to said distal end for distending said bladder 5 with a fluid 25 from a fluid system and heating means (44) for heating said fluid (25), said heating means being positioned internally to said bladder (5). The applicator of claim 1, wherein said catheter comprises at its distal end rigid tubing (3) and flexible tubing (10) for introducing said fluid and transporting it into the distendable bladder (5) and for connection to control (30) means. The applicator of claim 2, wherein said rigid tubing (3) comprises polytetrafluorethylene tubing. The applicator of claim2, wherein said flexible tubing (10) comprises polytetrafluorethylene tubing. The applicator of any one of claims 1 to 4, wherein said bladder (5) when distended is capable of resisting an internal pressure of at least 40.0 kPa (300mmHg) without rupturing and a temperature of at least 121.1°C (250°F) without carbonizing said bladder (5). The applicator of any one of claims 1 to 5, wherein the applicator has an end portion (1) with a plastic sheath (15) which contains the flexible tubing (10) and an electrical sheath (16). The applicator of any one of claims 1 to 6, wherein said heating means (44) is positioned completely within said bladder (5). The applicator of any one of claims 1 to 7, wherein a shield (45) prevents said bladder (5) from contacting the heating means (44). The applicator of claim 8, wherein said shield (45) comprises ventilation holes (46). The applicator of any one of claims 1 to 9, wherein within said bladder (5) a thermocouple (48) for measuring the temperature of said fluid (25) is located. The applicator of any one of claims 1 to 10 further comprising positioning means (4) for positioning said bladder (5) in the uterus. The applicator of claim 11, wherein said positioning means (4) comprises scale gradations (4) on said rigid tubing (3) for indicating depth of insertion of said bladder (5) into the uterus. The applicator of any one of claims 1 to 12 further comprising inflating and deflating means (14) connected to said distal end for controlling the amount of said fluid (25) in the fluid system.

Inventors: BOLDUC LEE R, NEUWIRTH ROBERT S, BOLDUC, LEE R., NEUWIRTH, ROBERT S.
Applicants: GYNELAB PROD INC, GYNELAB PRODUCTS, INC
Application year: 1989
Main classification: A61B17
IPC codes: A61B17, A61B19, A61B18, A61F7