Methods and apparatus for therapeutic cauterization of predetermined volumes of biological tissue

• US 5,947,964 A
• Filed: 07/03/1997
• Issued: 09/07/1999
• Est. Priority Date: 03/03/1995
• Status: Expired due to Fees

• Current Assignee: Intact Medical Corporation (Medtronic Plc)
• Original Assignee: Neothermia Corporation (Medtronic Plc)
• Inventors: Eggers, Philip E., Shmulewitz, Ascher
• Primary Examiner(s): Dvorak, Linda C. M.
• Assistant Examiner(s): GIBSON, ROY DEAN
• Application Number:
  US08/887,663
• Time in Patent Office: 796 Days
• Field of Search: 606/41, 606/42, 606/45, 606/48-50, 606/29, 606/31, 607/98-102
• US Class Current: 606/41
• CPC Class Codes: A61B 10/02 Instruments for taking cell samples or for biopsy A61B10/0038 and A61B10/0045 take precedence; needle locating or guiding means A61B17/3403; samplers for enzymology or microbiology C12M1/26; sampling or preparing biological specimens G01N33/48
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/1477 Needle-like probes
• CPC Class Codes: A61B 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/1487 Trocar-like, i.e. devices producing an enlarged transcutaneous opening
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/00261 arranged in a line
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00666 using a threshold value
• CPC Class Codes: A61B 2018/00678 upper
• CPC Class Codes: A61B 2018/00708 switching the power on or off
• CPC Class Codes: A61B 2018/00761 Duration
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00886 Duration
• CPC Class Codes: A61B 2018/0091 Handpieces of the surgical instrument or device
• CPC Class Codes: A61B 2018/00916 with means for switching or controlling the main function of the instrument or device
• CPC Class Codes: A61B 2018/126 : bipolar
• CPC Class Codes: A61B 2018/1273 : including multiple generators in one device
• CPC Class Codes: A61B 2018/128 : generating two or more frequencies
• CPC Class Codes: A61B 2018/1425 : Needle
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 5/0531 : Measuring skin impedance
• CPC Class Codes: A61B 5/4893 : Nerves

Abstract

Methods and apparatus are provided for cauterizing predetermined volumes of abnormal biological tissue using a user selectable or adjustable energy applicator including two or more electrodes having electrode parameters configured to cause cauterization of predetermined volumes when operated in a bipolar mode. The energy applicators are employed with a control device that couples the energy applicators to a power source and includes circuitry for interrupting activation of the energy applicator when the current between the two or more electrodes decreases more than a predetermined amount from the current sensed upon initial activation of the energy applicator.

Claims

1. Apparatus for use with a power source to provide therapeutic cauterization of biological tissue, the apparatus comprising:

an energy applicator adapted to cauterize a predetermined volume of tissue when supplied with a specified power input by the power source, the energy applicator comprising;

a base having a longitudinal axis;

proximal and distal expandable members affixed to the base;

a distal electrode disposed covering a portion of the distal expandable member and a proximal electrode disposed covering a portion of the proximal expandable member; and

a hub for electrically coupling the energy applicator to a control device;

a handle including a portion that accepts the hub of an energy applicator adapted to couple an electric current to the distal electrode and the proximal electrode; and

a cable for coupling the handle to the power source.

2. The apparatus as defined in claim 1, wherein the distal end of the energy applicator comprises a sharpened end.

3. The apparatus as defined in claim 1, wherein the base of the energy applicator comprises a hollow cylindrical shaft.

4. The apparatus as defined in claim 3 wherein the base of the energy applicator has a sharpened distal end to facilitate introduction and advancement of the energy applicator into biological tissue.

5. The apparatus as defined in claim 1 further comprising:

control circuitry including a current detector adapted to measure a current flowing between the proximal and distal electrodes.

6. The apparatus as defined in claim 1 wherein the base of the energy applicator comprises a catheter having a longitudinal axis, the energy applicator further comprising means for orienting the proximal and distal electrodes at an angle to the longitudinal axis.

7. The apparatus as defined in claim 1, further comprising:

a timer that measures a preset period of time; and

circuitry that terminates supply of power to the energy applicator when the preset period elapses.

8. The apparatus as defined in claim 1, further comprising:

a coding element disposed within the energy applicator; and

circuitry that measures a value of a parameter of the coding element to determine an upper power or current limit value corresponding to a maximum power density or current density to be applied to the biological tissue.

9. The apparatus as defined in claim 1, wherein the proximal and distal expandable members have a contracted diameter for insertion into the biological tissue.

10. The apparatus as defined in claim 9 wherein the energy applicator further comprises means for injecting a pressurizing fluid into the proximal and distal expandable members, the pressurizing fluid moderating the temperature of the electrode disposed on the proximal and distal expandable members.

11. Apparatus for use in combination with a power source for providing therapeutic cauterization of biological tissue, the apparatus comprising:

an energy applicator having unique electrode parameters that provide cauterization of a predetermined volume of biological tissue, the energy applicator comprising;

a shaft having a longitudinal axis;

first and second expandable members affixed to the shaft;

a first electrode disposed on the first expandable member and second electrode disposed on the second expandable member, the distance between the first and second electrodes determining a size and shape of a zone of cauterization produced in biological tissue by the energy applicator; and

a handle that is adapted to couple the energy applicator to the power source.

12. The apparatus as defined in claim 11, wherein the first and second electrodes are coaxially aligned.

13. The apparatus as defined in claim 11 wherein the shaft includes a lumen.

14. The apparatus as defined in claim 11 wherein the shaft has a sharpened tip to facilitate introduction and advancement of the energy applicator into biological tissue.

15. The apparatus as defined in claim 11, further comprising:

a current detector adapted to measure a current level between the first and second electrodes.

16. The apparatus as defined in claim 11, wherein the shaft of the energy applicator comprises a catheter having a longitudinal axis, the energy applicator further comprising means for orienting the first and second electrodes at an angle to the longitudinal axis.

17. The apparatus as defined in claim 11, further comprising:

a timer that measures a preset period of time; and

circuitry for terminating supply of power to the energy applicator when the preset period elapses.

18. The apparatus as defined in claim 11, wherein the energy applicator contains a coding element, the apparatus further comprising circuitry that measures a value of a parameter of the coding element to determine an upper power or current limit value corresponding to a maximum power density or current density to be applied to the biological tissue.

19. The apparatus as defined in claim 11, wherein the first and second expandable members have a contracted diameter for insertion into the biological tissue.

20. The apparatus as defined in claim 19 wherein the energy applicator further comprises means for injecting a pressurizing fluid into the first and second expandable members, the pressurizing fluid moderating the temperature of the first and second electrodes.