Balloon catheter method for intra-urethral radio-frequency urethral enlargement

• US 6,447,505 B2
• Filed: 07/10/1998
• Issued: 09/10/2002
• Est. Priority Date: 02/11/1998
• Status: Expired due to Fees

• Current Assignee: Cosman Company Incorporated, Massachusetts General Hospital (Mass General Brigham, Inc.)
• Original Assignee: Cosman Company Incorporated, The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Cosman, Eric R., Rittman, William J. III, Goldberg, S. Nahum, McGovern, Francis J.
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/113,683
• Publication Number:
  US 20010003798A1
• Time in Patent Office: 1,523 Days
• Field of Search: 606/41, 606/49, 606/50, 607/98, 607/99, 607/105, 607/113
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00678 upper
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00755 Resistance or impedance
• 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 2018/00821 measured by a thermocouple
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61B 2090/3782 transmitter or receiver in catheter or minimal invasive instrument
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 2218/007 Aspiration

Abstract

Relief of urethral obstruction is achieved by heat ablation of prostatic tissue by an ablation instrument passed within the urethra to a position in the prostate near the point of urethral obstruction. An electrode is coupled to a high-frequency power supply to ablatively heat the urethra and the prostatic tissue near the urethra. Guidance of the electrode placement may be monitored by an imaging device. The instrument may consist of a catheter with an inflatable balloon structure for positioning the instrument. The temperature of the tissue may be sensed at the electrode to control the high-frequency heating energy and ablation process.

Claims

1. A method of relieving urethral obstruction in a patient having a urethra, a prostate and a bladder, the method comprising the steps of:

providing a catheter that comprises;

an electrically conductive active sector electrode disposed on an outer surface of the catheter, and

an inflatable balloon proximate to a distal end of the catheter wherein the inflatable balloon may be inflated by injection of fluid through a port in the catheter;

inserting the catheter into the urethra of the patient a distance sufficient to provide contact between the electrode and at least a portion of the urethra and to insert the balloon into the bladder of the patient;

inflating the balloon;

positioning the electrode within the urethra of the patient at a location proximate the prostate where urethral enlargement is desired; and

applying a high-frequency signal to the electrode to elevate the temperature of the urethra to at least 50°

C. to induce heat ablation of at least a portion of the urethra and at least a portion of periurethral tissue in the patient, thereby inducing ablative reduction of tissue mass of the urethra and nearby tissue to reduce the urethral obstruction.

2. The method of claim 1 wherein the positioning step further comprises the step of viewing an operative field within the patient to position the electrode relative to the obstruction.

3. The method of claim 1 further comprising the step of measuring a temperature of tissue proximate the electrode.

4. The method of claim 1 further comprising the step of measuring an impedance of tissue proximate the electrode.

5. The method of claim 1 wherein the step of providing the cather includes providing the electrode with a plurality of electrically conductive areas separated by at least one electrical insulator.

6. The method of claim 1 wherein the step of providing the catheter includes providing the catheter defining two internal channels that are adapted to carry fluid, a first one of the two internal channels having a port at a proximal end of the catheter to allow inflow of fluid to inflate the balloon, and a second one of the two internal channels having a distal opening at a distal end of the catheter and a proximal opening at a proximal end of the catheter to allow drainage of urine from the bladder of the patient when the catheter is inserted into the urethra and the balloon is inflated in the bladder.

7. The method of claim 1 wherein applying the signal includes enlarging the passageway relative to a normal size of the urethral passage.

8. The method of claim 1 wherein applying the signal includes applying an output through the electrode to a return electrode.

9. The method of claim 1 wherein the electrode is a non-cooled electrode.

10. A method of treating the urethral passage, comprising:

placing a distal portion of an elongate member intraurethrally into the urethral passage, the elongate member having a circumferential, electrically conductive sector electrode disposed on an outer surface of the distal portion of the elongate member and arranged about a portion of a circumference of the elongate member, and

energizing the electrode with high frequency energy to elevate the temperature of the urethra to at least 50°

C. to ablate tissue of a wall defining the urethral passage and ablate adjacent prostate tissue to form a cavity communicating with the urethral passage.

11. The method of claim 10 wherein energizing the electrode forms a cavity in the wall and adjacent prostate tissue having a diameter in the range of about 0.3 to 5 cm.

12. The method of claim 10 wherein energizing the electrode elevates a temperature of the wall and adjacent prostate tissue to about 50 to 100°

C.

13. The method of claim 12 wherein energizing the electrode includes elevating the temperature for about six minutes.

14. The method of claim 10 wherein energizing the electrode includes connecting the electrode to a high frequency generator.

15. The method of claim 10 wherein energizing the electrode includes forming the cavity such that the urethral passage is enlarged relative to a normal size of the urethral passage.

16. The method of claim 10 wherein energizing the electrode includes applying the high frequency energy through the electrode to a return electrode.

17. The method of claim 10 further comprising imaging the electrode to monitor the position of the electrode.

18. The method of claim 17 wherein imaging includes ultrasonic imaging.

19. The method of claim 18 wherein imaging includes inserting an ultrasonic scanner transrectally.

20. The method of claim 17 wherein imaging includes CT imaging.

21. The method of claim 17 wherein imaging includes MR imaging.

22. The method of claim 10 further comprising detecting a temperature level of tissue surrounding the electrode.

23. The method of claim 10 further comprising providing the elongate member with multiple, circumferential, electrically conductive sector electrodes at the distal portion.

24. The method of claim 23 wherein energizing the electrode includes energizing the multiple sector electrodes in a bi-polar configuratior.

25. The method of claim 23 wherein providing includes affixing an electric insulator over a portion of a ring electrode to form the sector electrodes.

26. The method of claim 10 wherein the electrode is a non-cooled electrodes.

27. A method of treating the urethral passage, comprising:

placing a distal portion of an elongate member intraurethrally into the urethral passage, the elongate member having a plurality of electrically discrete sector electrodes arranged about a portion of a circumference of the elongate member, and

energizing the electrodes with high frequency energy to ablate tissue of a wall defining the urethral passage and adjacent prostate tissue.

28. The method of claim 27 wherein energizing the electrodes with high frequency energy includes elevating the temperature of tissue of a wall defining the urethral passage to at least 50°

C.

29. The method of claim 27 wherein the electrodes are non-cooled electrodes.