Method and apparatus for endometrial ablation

• US 6,041,260 A
• Filed: 06/07/1995
• Issued: 03/21/2000
• Est. Priority Date: 05/01/1992
• Status: Expired due to Term

• Current Assignee: Sherwood Services AG
• Original Assignee: Vesta Medical, Inc.
• Inventors: Sullivan, Vincent N., Stern, Roger A., Marion, Robert L.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US08/481,940
• Time in Patent Office: 1,749 Days
• Field of Search: 606/27, 606/28, 606/32, 606/33, 606/40, 606/41, 606/45, 606/49, 607/98, 607/99, 607/113, 607/116, 607/138, 607/148
• US Class Current: 607/98
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 2017/00092 using thermocouples
• CPC Class Codes: A61B 2017/00101 using an array of thermosensors
• CPC Class Codes: A61B 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/4216 Operations on uterus, e.g. endometrium
• CPC Class Codes: A61B 2018/00065 porous
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00113 with foam
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00559 Female reproductive organs
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00797 measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00815 measured by a thermistor
• CPC Class Codes: A61B 2018/124 switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/1253 : monopolar
• CPC Class Codes: A61B 2018/1465 : Deformable electrodes
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61N 1/06 : for high-frequency therapy
• CPC Class Codes: A61N 1/40 : Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals
• CPC Class Codes: A61N 1/403 : for thermotherapy, e.g. hyperthermia

Abstract

An endometrial ablation apparatus and method wherein an RF current having a frequency of between 250 kHz and 100 MHz is passed through the entire surface of an endometrium in order to provide heating of the endometrium. An electroconductive expandable member such as a balloon is used as the medium for passing the current and causing the heating of the endometrium. The temperature of the endometrium is raised to a temperature between 45° C. and 90° C. and preferably not above 70 for a time sufficient to destroy the cells of the lining while maintaining the average temperature of the myometrium at a temperature below approximately 42° C. The expandable balloon is connected to a power source which provides the radio frequency power having the desired characteristics to selectively heat the endometrial lining to the desired temperature. The balloon can be constructed with an electroconductive elastomer such as a mixture of polymeric elastomer and electroconductive particles or can be a non-extensible bladder having a shape and a size, in its fully expanded form, which will extend the organ and effect contact with the endometrial lining to be destroyed. The electroconductive member may consist of a plurality of electrode area segments having a thermistor associated with each electrode segment whereby the temperature from each of said plurality of segments is monitored and controlled by a feedback arrangement from the thermistors.

Claims

1. An ablation apparatus for selectively destroying tissue of a hollow body organ, said apparatus comprising:

an electroconductive, expandable electrode means for effecting electrical contact with an inner surface of the organ, said expandable electrode means being a bladder provided with a plurality of separate electrodes on a surface of the bladder;

a plurality of temperature sensors, wherein a temperature sensor is associated with each electrode and is mounted in close proximity to its associated electrode;

a radio frequency power means connected to said expandable electrode means for selectively providing power to said electrodes to heat said tissue by passing current through the tissue; and

control means for controlling the power means to heat the selected tissue to a uniform temperature of at least 45°

C.

2. The apparatus according to claim 1, further including a temperature measurement circuitry including a first switch matrix means for selectively applying RF power to at least one of said plurality of electrode power leads, a first reference voltage point, a second reference voltage point and a second switch matrix means for connecting a selected one of said plurality of electrode power leads to said first reference voltage point while simultaneously connecting all other ones of said electrode leads to said second reference voltage point.

3. An ablation apparatus of claim 2, wherein the bladder is a non-extensible bladder.

4. An ablation apparatus of claim 1, wherein the control means is a means for controlling the power means to heat the selected tissue to a uniform temperature within the range of from 45°

to 90°

C.

5. An electrically conductive expandable electrode assembly for providing electrical contact with an inner surface of a hollow body organ for the purpose of ablating tissue of the organ, said assembly comprising:

an expandable bladder having an inner surface and an outer surface, one of said inner and said outer surface being provided with a plurality of separate electrodes and the other of said inner and outer surface being provided with a plurality of thermistors corresponding to each of said plurality of electrodes.

6. An electrode assembly of claim 5, wherein each of said plurality of electrodes further comprises a plurality of holes, with one of said plurality of holes of each electrode extending through said bladder from said outside surface to said inside surface, and said extended holes providing electrical continuity between said electrodes and said other surface, said other surface further including a plurality of power leads, each lead being electrically connected to a corresponding one of said electrodes, said leads each extending from one extremity of said bladder to a respective one of said extended holes, each said power lead also extending to a respective one of said thermistors, whereby the relationship between the plurality of holes in each of said electrodes and said power leads provides for uniform heating on a surface of each of the respective electrodes.

7. The expandable electrode assembly according to claim 5, wherein each of said thermistors is further connected to a common ground lead on said other surface.

8. An ablation method for selectively destroying selected tissue of a hollow body organ, comprising the steps of:

a) passing a radio frequency current through the selected tissue from an expandable electrode member conforming to the inner surface of the organ, the expandable electrode member including an expandable bladder, a plurality of electrodes mounted on the bladder, and a plurality of temperature sensors, wherein a temperature sensor is associated with each of said electrodes and is mounted in close proximity to its associated electrode; and

b) controlling the current from each electrode using feedback from said plurality of temperature sensors to uniformly heat the selected tissue in a single operation to a temperature of at least 45°

C.

9. An ablation method for destroying lining of a body organ having a supporting mass under the lining, said method comprising the steps of:

passing a radio frequency current having a frequency of at least 250 kHz from an expandable member conforming to the lining and filled with expansion medium, wherein said current is passed through a portion of the lining to resistively heat in a single operation the portion of the lining to a temperature of at least 45°

C. for a time sufficient to destroy cells of the lining while maintaining an average temperature of the supporting mass at a temperature below approximately 42°

C.

10. The method of claim 9, wherein the body organ is a uterus, the lining is the endometrium of the uterus, and the supporting mass is a myometrium of the uterus.

11. The method of claim 9, wherein said portion of the lining includes the entire lining.

12. A method of claim 9, further comprising monitoring the temperature of the lining and reducing said current when said monitored temperature exceeds a predetermined value.

13. An ablation apparatus for selectively destroying lining of an organ in a body, having an outer surface comprising an electro-conductive, expandable electrode means which includes a non-extensible bladder having a shape and size, in its fully expanded form, which will extend the organ and effect contact with the lining to be destroyed and an external electrode means adapted to contact the outer surface of the body, the expandable electrode means containing an expansion medium, the non-extensible bladder having an inner surface that is coated with electroconductive material and a wall thickness of less than about 0.25 mm;

and a power source connected to the expandable electrode means and to the external electrode means, the power source being adapted to provide radio-frequency electric power to the expandable electrode means at a frequency of at least 250 kHz in an amount which, when current is passed from the expandable electrode means through the lining, will heat the lining of the organ to a temperature of at least 45°

C.

14. An ablation apparatus for selectively destroying tissue of a hollow body organ, said apparatus comprising an electroconductive, expandable electrode means for effecting electrical contact with an inner surface of the organ, said expandable electrode means including an expandable balloon and a plurality of electrodes on a surface of the balloon;

a plurality of thermistors, each associated with one of said plurality of electrodes;

an external electrode means for attachment to an outer surface of the body;

a radio frequency power means connected to said expandable electrode means and the external electrode means for providing power to said electrodes; and

a plurality of electrode power leads each of which being electrically connected to a respective one of said plurality of electrodes and a respective one of said thermistors.