Peri-urethral ablation

• US 6,517,534 B1
• Filed: 08/15/1999
• Issued: 02/11/2003
• Est. Priority Date: 02/11/1998
• Status: Expired due to Fees

• Current Assignee: Cosman Company Incorporated, The General Hospital Corporation (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:
  US09/375,469
• Time in Patent Office: 1,276 Days
• Field of Search: 606/41, 606/49, 606/50, 606/28, 606/29, 607/98, 607/99, 607/105, 607/113
• US Class Current: 606/41
• CPC Class Codes: A61B 18/08 by means of electrically-heated probes
• CPC Class Codes: A61B 18/1477 Needle-like probes
• 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 2018/00005 Cooling or heating of the probe or tissue immediately surrounding the probe
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00261 arranged in a line
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00517 Urinary bladder or urethra
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61B 2018/00553 Sphincter
• 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 2018/1425 : Needle
• 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 probe passed within the urethra to a position in the prostate near the point of urethral obstruction. The probe is coupled to a power supply to deliver power to tissue near the probe and thus to ablatively heat the urethra and the prostatic tissue near the urethra. The temperature of the tissue is sensed at the probe to control the heating and ablation process. In one embodiment, the probe has a blunt tip to help prevent piercing of the wall of the urethra during insertion of the probe into the urethra through the penis and the positioning of the probe tip near to the point of urethral obstruction. Several forms of probes, apparatus, and methods accommodate the specific objectives.

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 including;

a plurality of ring electrodes on an external surface of the catheter in a flexible region of the catheter configured and arranged to substantially maintain flexibility in the region, 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 electrodes and at least a portion of the urethra and to insert the balloon into the bladder of the patient;

inflating the balloon;

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

applying a high-frequency signal to at least one of the electrodes to elevate the temperature to at least 50°

C. and induce heat ablation of at least a portion of the urethra wall 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 applying the signal includes enlarging the passageway relative to a normal size of the urethral passage.

3. The method of claim 1 wherein applying the signal includes applying the output through at least one of the electrodes to a return electrode.

4. The method of claim 1 including selecting one or more electrodes to be energized to grade a size of ablation.

5. The method of claim 1 wherein applying the signal includes energizing the electrodes in a bi-polar configuration.

6. The method of claim 1 wherein the step of providing includes at least one of the plurality of electrodes having a length greater than about 1 cm.

7. The method of claim 1 further comprising thereafter applying the high-frequency signal to a second electrode of the plurality of electrodes.

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

placing a distal portion of an elongate member intraurethrally into the urethral passage, a flexible region of the distal portion of the elongate member having a plurality of ring electrodes on an external surface of a catheter configured and arranged to substantially maintain flexibility in the region, and

energizing at least one of the electrodes with high frequency energy to elevate the temperature to at least 50°

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

9. The method of claim 8 wherein energizing at least one of the electrodes forms a cavity in the wall and adjacent prostate tissue having a diameter in the range of about 0.3 to 5 cm.

10. The method of claim 8 wherein energizing at least one of the electrodes elevates a temperature of the wall and adjacent prostate tissue to about 50 to 100°

C.

11. The method of claim 10 wherein energizing at least one of the electrodes includes elevating the temperature for about six minutes.

12. The method of claim 8 wherein energizing at least one of the electrodes includes connecting the electrode to a high frequency generator.

13. The method of claim 8 wherein energizing at least one of the electrodes includes forming the cavity such that the urethral passage is enlarged relative to a normal size of the urethral passage.

14. The method of claim 8 wherein energizing at least one of the electrodes includes applying the high frequency energy through at least one of the electrodes to a return electrode.

15. The method of claim 8 further comprising imaging the electrodes to monitor the position of the electrodes.

16. The method of claim 15 wherein imaging includes ultrasonic imaging.

17. The method of claim 16 wherein imaging includes inserting an ultrasonic scanner transrectally.

18. The method of claim 15 wherein imaging includes CT imaging.

19. The method of claim 15 wherein imaging includes MR imaging.

20. The method of claim 8 further comprising detecting a temperature level of tissue surrounding the electrodes.

21. The method of claim 8 including selecting one or more electrodes to be energized to grade a size of ablation.

22. The method of claim 8 wherein energizing at least one of the electrodes includes energizing the electrodes in a bi-polar configuration.

23. The method of claim 8 wherein the step of providing includes at least one of the plurality of electrodes having a length greater than about 1 cm.

24. The method of claim 8 further comprising thereafter energizing a second electrode of the plurality of electrodes with the high-frequency signal.

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

placing a distal portion of an elongate member intraurethrally into the urethral passage, a flexible region of the distal portion of the elongate member having a plurality of ring electrodes on an external surface of a catheter configured and arranged to substantially maintain flexibility in the region, each electrode being a non-cooled electrode, and

energizing at least one of the electrodes with high frequency energy to elevate the temperature to at least 50°

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