Electrosurgical apparatus and methods for ablating tissue

• US 20020052600A1
• Filed: 04/17/2001
• Published: 05/02/2002
• Est. Priority Date: 05/10/1993
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Willink, Christopher L., Ormsby, Theodore C., Davison, Terry S.
• Granted Patent: US 6,746,447 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• 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 18/149 bow shaped or with rotatable body at cantilever end, e.g. for resectoscopes, or coagulating rollers
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00101 using an array of thermosensors
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00119 with metal oxide nitride
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00291 using suction
• CPC Class Codes: A61B 2018/00327 Ear, nose or throat
• CPC Class Codes: A61B 2018/00392 Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/00505 Urinary tract
• CPC Class Codes: A61B 2018/00577 : Ablation
• CPC Class Codes: A61B 2018/00583 : Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00601 : Cutting
• CPC Class Codes: A61B 2018/00666 : using a threshold value
• CPC Class Codes: A61B 2018/00678 : upper
• CPC Class Codes: A61B 2018/00702 : Power or energy
• CPC Class Codes: A61B 2018/0072 : Current
• CPC Class Codes: A61B 2018/00726 : Duty cycle
• CPC Class Codes: A61B 2018/00779 : Power or energy
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00827 : Current
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00982 : combined with or comprising means for visual or photographic inspections inside the body, e.g. endoscopes
• CPC Class Codes: A61B 2018/1213 : creating an arc
• 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 2018/126 : bipolar
• CPC Class Codes: A61B 2018/1273 : including multiple generators in one device
• CPC Class Codes: A61B 2018/1407 : Loop
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 2018/165 : Multiple indifferent electrodes
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration

Abstract

Electrosurgical methods, systems, and apparatus for the controlled ablation of tissue from a target site of a patient. An electrosurgical instrument includes a working portion having a plurality of working zones differentiated according to their relative rates of aspiration and ablation. The instrument further includes an aspiration channel in communication with a plurality of aspiration ports, and a plurality of active electrodes disposed on the working portion. Each of the plurality of working zones may have at least one of the plurality of active electrodes and at least one of the plurality of aspiration ports. The aspiration rate of each working zone is dependent, inter alia, on the number, size, and distribution of the aspiration ports on that zone. In one embodiment, the ablation rate of a working zone is inversely related to the aspiration rate of that zone. Each of the plurality of active electrodes is adapted for ablating tissue to form low molecular weight ablation by-products. The ablation by-products may be aspirated from the target site via aspiration port(s) on one or more of the plurality of working zones.

Claims

1. An electrosurgical probe for ablating tissue from a target site, comprising:

a working portion having a plurality of aspiration ports arranged thereon, at least two of the plurality of aspiration ports spaced from each other and having substantially different aspiration rates.

2. The electrosurgical probe of claim 1, wherein the at least two of the plurality of aspiration ports are spaced axially from each other.

3. The electrosurgical probe of claim 1, wherein the at least two of the plurality of aspiration ports are dissimilar in size.

4. The electrosurgical probe of claim 1, wherein the working portion includes a first working zone and a second working zone, each of the first working zone and the second working zone having at least one aspiration port, and wherein a first aspiration rate in the first working zone is less than a second aspiration rate in the second working zone.

5. The electrosurgical probe of claim 4, wherein each of the first working zone and the second working zone includes at least one active electrode, each of the first working zone and the second working zone adapted for ablating tissue and for aspirating ablation by-products, wherein the first working zone has a first ablation rate and the second working zone has a second ablation rate, and the first ablation rate is greater than the second ablation rate.

6. The electrosurgical probe of claim 1, wherein the working portion includes a first working zone and a second working zone, wherein the first working zone is adapted for aggressive ablation of the tissue from the target site, and the second working zone is adapted for rapid aspiration of unwanted materials.

7. The electrosurgical probe of claim 1, wherein the working portion includes a plurality of working zones, and wherein the plurality of working zones are arranged on the same plane.

8. The electrosurgical probe of claim 1, wherein the working portion includes a plurality of working zones, and wherein the plurality of working zones are arranged on at least two different planes.

9. An electrosurgical probe for ablating tissue from a target site, comprising:

a shaft having a shaft proximal end and a shaft distal end;

a working portion located at the shaft distal end, the working portion including a plurality of working zones, wherein a suction pressure gradient exists between each of the plurality of working zones;

a plurality of active electrodes disposed on the working portion; and

an aspiration unit including an aspiration channel in communication with a plurality of aspiration ports, the plurality of aspiration ports arranged on the working portion.

10. The probe of claim 9, wherein the plurality of working zones include a first working zone and a second working zone, the first working zone characterized as having a low aspiration rate and a high ablation rate, and the second working zone characterized as having a high aspiration rate and a low ablation rate.

11. The probe of claim 10, wherein the first working zone is located distal to the second working zone.

12. The probe of claim 9, wherein each of the plurality of working zones includes at least one of the plurality of aspiration ports.

13. The probe of claim 12, wherein the at least one aspiration port of the first working zone has a smaller area than the at least one aspiration port of the second working zone.

14. The probe of claim 9, wherein at least a portion of the plurality of aspiration ports are located at the periphery of the working portion.

15. The probe of claim 9, wherein each of the plurality of working zones includes at least one of the plurality of active electrodes.

16. The probe of claim 9, further comprising a return electrode disposed on the shaft distal end.

17. The probe of claim 9, further comprising an electrically insulating electrode support, each of the plurality of active electrodes arranged on the electrode support.

18. The probe of claim 17, wherein the plurality of aspiration ports are arranged within the electrode support.

19. The probe of claim 17, wherein the electrode support comprises a material selected from the group consisting of a ceramic, a glass, a fluoropolymer, and a silicone rubber.

20. The probe of claim 17, wherein the electrode support includes a first plane and a second plane, and the first plane is beveled at an angle in the range of from about 15°

to 75°

with respect to the longitudinal axis of the probe.

21. The probe of claim 9, wherein at least one of the plurality of active electrodes comprises a wire loop.

22. The probe of claim 21, wherein the wire loop at least partially extends across at least one of the plurality of aspiration ports.

23. The probe of claim 9, wherein each of the plurality of active electrodes comprises a metal selected from the group consisting of platinum, tungsten, palladium, iridium, and titanium.

24. The probe of claim 9, wherein each of the plurality of active electrodes comprises a platinum/iridium alloy.

25. The probe of claim 9, wherein each of the plurality of active electrodes comprises from about 80% to 95% platinum and from about 5% to 20% iridium, by weight.

27. The electrosurgical probe of claim 26, wherein at least two of the plurality of aspiration ports are spaced from each other, and each of the plurality of working zones have substantially different aspiration rates.

28. The electrosurgical probe of claim 26, wherein a first of the plurality of aspiration ports is located in a first working zone, and a second of the plurality of aspiration ports is located in a second working zone, wherein a first aspiration rate of the first aspiration port is less than a second aspiration rate of the second aspiration port.

29. The electrosurgical probe of claim 28, wherein a first ablation rate in the first working zone is greater than a second ablation rate in the second working zone.

30. The electrosurgical probe of claim 26, wherein the working portion includes a first working zone and a second working zone, each of the first working zone and the second working zone includes at least one active electrode, each of the first working zone and the second working zone adapted for ablating tissue and for aspirating ablation by-products, and wherein the first working zone and the second working zone have different ablation rates.

26. An electrosurgical probe for ablating tissue from a target site, comprising:

a working portion having a plurality of aspiration ports, the working portion including a plurality of working zones, and each of the plurality of working zones having at least one of the plurality of aspiration ports arranged thereon.

31. An electrosurgical apparatus for removing tissue from a target site, comprising:

a working portion including a plurality of working zones, wherein a suction pressure gradient exists between each of the plurality of working zones.

32. The apparatus of claim 31, wherein the plurality of working zones include a first working zone and a second working zone, wherein the first working zone is characterized by a higher rate of ablation than the second working zone.

33. The apparatus of claim 32, wherein the first working zone is characterized by a lower rate of suction than the second working zone.

34. The apparatus of claim 33, wherein the first working zone is adapted for facile initiation and maintenance of a plasma thereat.

35. The apparatus of claim 31, wherein the first working zone is spaced apart from the second working zone.

36. The apparatus of claim 31, wherein the first working zone is spaced distally from the second working zone.

37. The apparatus of claim 31, wherein the working portion occupies at least two different planes, and wherein the first working zone occupies a first plane and the second working zone occupies a second plane.

38. The apparatus of claim 31, wherein the working portion includes a first working zone and a second working zone, each of the first working zone and the second working zone include at least one aspiration port, the first working zone has a first aspiration port area, and the second working zone has a second aspiration port area, and wherein the first aspiration port area is less than the second aspiration port area.

39. The apparatus of claim 38, wherein the at least one aspiration port of the second working zone is larger than the at least one aspiration port of the first working zone.

40. The apparatus of claim 39, wherein the first working zone is located distal to the second working zone.

41. An electrosurgical apparatus for ablating tissue at a target site, comprising:

a shaft having a shaft distal end portion and a shaft proximal end portion; and

a working portion located at the shaft distal end portion, the working portion adapted for ablating tissue and for aspirating ablation by-products from the target site, the working portion including at least two working zones, each of the at least two working zones having at least one aspiration port.

42. The apparatus of claim 41, wherein the at least one aspiration port of a first working zone is adapted for creating a first localized environment, and the at least one aspiration port of a second working zone is adapted for creating a second localized environment, wherein the first localized environment is suitable for facile generation and maintenance of a plasma at the first working zone, and wherein the second localized environment is less suitable for generation and maintenance of a plasma at the second working zone.

43. The apparatus of claim 42, wherein the first working zone is adapted for high rates of tissue ablation.

44. The apparatus of claim 42, wherein the second working zone is adapted for high rates of aspiration of a fluid therefrom.

46. The method of claim 45, wherein the first working zone is characterized by a first aspiration rate, the second working zone is characterized by a second aspiration rate, and the first aspiration rate is less than the second aspiration rate.

47. The method of claim 45, wherein each of the plurality of working zones is characterized by a different aspiration rate.

48. The method of claim 45, wherein a suction pressure gradient exists between each of the plurality of working zones.

49. The method of claim 45, wherein the first working zone is characterized by a first ablation rate, the second working zone is characterized by a second ablation rate, and the first ablation rate is greater than the second ablation rate.

50. The method of claim 45, further comprising:

e) after said step c), aspirating a second portion of the gaseous ablation by-products from the first working zone.

51. The method of claim 45, wherein said step c) further generates resected tissue fragments, and the method further comprises:

f) after said step c), ablating the resected tissue fragments using the second working zone.

52. The method of claim 45, further comprising:

g) prior to said step c), delivering an electrically conductive fluid to at least one of the plurality of working zones.

53. The method of claim 45, wherein the first working zone includes at least one active electrode, and the method further comprises:

h) during said step c), applying a high frequency voltage between the at least one active electrode and a return electrode, the high frequency voltage sufficient to generate a plasma in the vicinity of at least the first working zone.

54. The method of claim 45, wherein each of the plurality of working zones has at least one aspiration port.

55. The method of claim 45, wherein the second working zone has a plurality of aspiration ports therein, and the plurality of aspiration ports are adapted for rapidly aspirating a fluid from a site of ablation of the target tissue.

56. The method of claim 55, wherein the fluid comprises bubbles of gaseous ablation by-products entrapped within a liquid.

57. The method of claim 56, wherein the liquid comprises blood or saline.

58. The method of claim 45, wherein each of the plurality of working zones has at least one active electrode.

59. The method of claim 45, wherein the probe includes a plurality of active electrodes disposed on the working portion, and at least one of the plurality of active electrodes comprises a metal selected from the group consisting of platinum, tungsten, palladium, iridium, and titanium.

60. The method of claim 59, wherein at least one of the plurality of active electrodes comprises a platinum/iridium alloy.

61. The method of claim 59, wherein at least one of the plurality of active electrodes comprises from about 80% to 95% platinum and from about 5% to 20% iridium.

45. A method of ablating a target tissue using an electrosurgical probe, comprising:

a) advancing a working portion of the probe towards the target tissue, the working portion including a plurality of working zones;

b) positioning a first working zone in at least close proximity to the target tissue;

c) ablating at least a portion of the target tissue using the first working zone, wherein said step c) generates gaseous ablation by-products; and

d) aspirating at least a first portion of the gaseous ablation by-products from a second working zone.

62. A method of removing tissue from a target site of a patient, comprising:

a) advancing a shaft distal end of an electrosurgical apparatus in the vicinity of the target site, the shaft distal having a working portion disposed thereon, the working portion including a plurality of working zones, the working portion having a plurality of active electrodes disposed thereon, each of the plurality of working zones having at least one of the plurality of active electrodes;

b) positioning at least one of the plurality of working zones in at least close proximity to the tissue at the target site;

c) applying a high frequency voltage between the plurality of active electrodes and a return electrode, wherein at least one of the plurality of active electrodes forms a plasma between at least one of the plurality of working zones and the tissue at the target site, such that at least a portion of the tissue at the target site is ablated; and

d) aspirating ablation by-products from the target site.

63. The method of claim 62, wherein the plasma is formed between a first working zone and the target site, and at least a portion of the ablation by-products are aspirated by a second working zone.

64. The method of claim 62, wherein the working portion includes a first working zone and a second working zone, and the at least one active electrode of the first working zone is capable of ablating tissue from the target site via molecular dissociation of tissue components to generate low molecular weight ablation by-products and resected tissue fragments.

65. The method of claim 64, wherein the at least one active electrode of the second working zone is capable of ablating resected tissue fragments via molecular dissociation of tissue components.

66. The method of claim 62, further comprising:

e) prior to said step c), delivering an electrically conductive fluid to at least one of the plurality of working zones or to the target site, wherein the electrically conductive fluid provides a current flow path between at least one of the plurality of active electrodes and the return electrode.

67. The method of claim 62, wherein the tissue at the target site is ablated to a controlled depth by plasma-induced volumetric removal of the tissue.

68. The method of claim 62, further comprising:

f) manipulating the apparatus such that the plurality of active electrodes are moved with respect to a surface of the tissue at the target site.

69. The method of claim 62, wherein the high frequency voltage applied between the plurality of active electrodes and the return electrode is in the range of from about 10 to 500 volts RMS.

70. The method of claim 62, wherein the tissue at the target site is exposed to a temperature in the range of from about 40°

C. to 90°

C.

71. The method of claim 62, wherein each of the plurality of active electrodes is in the form of a wire loop, the wire loop comprising a material selected from the group consisting of platinum, tungsten, palladium, iridium, and titanium.

72. An ablation and aspiration apparatus, comprising:

a working portion including a plurality of working zones;

a plurality of active electrodes disposed on the working portion; and

an aspiration unit including a plurality of aspiration ports, at least a portion of the plurality of aspiration ports arranged towards the periphery of the working portion.

73. The apparatus of claim 72, wherein each of the plurality of working zones includes at least one of the plurality of aspiration ports and at least one of the plurality of active electrodes.

74. The apparatus of claim 72, wherein each of the plurality of working zones is adapted to have a different ablation rate or a different aspiration rate.