System and method for ablation procedure monitoring using electrodes

• US 8,974,450 B2
• Filed: 02/03/2011
• Issued: 03/10/2015
• Est. Priority Date: 02/03/2011
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Brannan, Joseph D.
• Primary Examiner(s): Peffley, Michael
• Assistant Examiner(s): VAHDAT, KHADIJEH A
• Application Number:
  US13/020,562
• Publication Number:
  US 20120203217A1
• Time in Patent Office: 1,496 Days
• Field of Search: 606 33- 41
• US Class Current: 606/33
• CPC Class Codes: A61B 18/1815 using microwaves
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/1823 Generators therefor
• CPC Class Codes: A61B 2018/1838 Dipole antennas
• CPC Class Codes: A61B 2018/1869 with an instrument interstitially inserted into the body, e.g. needles
• CPC Class Codes: A61B 2090/062 penetration depth

Abstract

A microwave ablation system includes an antenna assembly configured to deliver microwave energy from a power source to tissue. One or more electrodes are disposed on the antenna assembly and are configured to be positioned relative to tissue upon insertion of the antenna assembly into tissue. The one or more electrodes are configured to generate a feedback signal in response to an electrical signal supplied thereto from the power source. The feedback signal corresponds to the proximity of tissue relative to the at least one electrode and is configured to be compared to a predetermined parameter to determine a depth of the insertion of the antenna assembly into tissue. The power source is configured to control the delivery of microwave energy to the antenna assembly based on the comparison.

Claims

1. A microwave ablation system, comprising:

an antenna assembly configured to deliver microwave energy from a power source to tissue; and

a pair of electrodes disposed on the antenna assembly and circumferentially spaced relative to each other in an interlocking configuration to define at least one longitudinal space therebetween, the pair of electrodes configured to be positioned relative to tissue upon insertion of the antenna assembly into tissue, at least one of the electrodes configured to generate a feedback signal in response to an electrical signal supplied thereto from the power source, the feedback signal corresponding to the proximity of tissue relative to the at least one longitudinal space and configured to be compared to at least one predetermined parameter to determine a depth of the insertion of the antenna assembly into tissue,

wherein the power source is configured to control the delivery of microwave energy to the antenna assembly based on the comparison.

2. The microwave ablation system according to claim 1, wherein the feedback signal is one of a measured impedance, a measured capacitance, and a measured inductance of at least one of the electrodes.

3. The microwave ablation system according to claim 1, wherein the at least one predetermined parameter is at least one impedance value.

4. The microwave ablation system according to claim 1, wherein the at least one predetermined parameter is a predetermined range of values.

5. The microwave ablation system according to claim 1, wherein the pair of electrodes is disposed proximal to a distal end of the antenna assembly.

6. The microwave ablation system according to claim 1, wherein each of the electrodes is semi-circular in shape.

7. The system according to claim 1, wherein the power source is configured to supply a first electrical potential to one of the electrodes and a second electrical potential to the other electrode.

8. The microwave ablation system according to claim 1, wherein the electrical signal supplied from the power source is RF energy.

9. A method of performing a tissue ablation procedure, comprising:

inserting an antenna assembly into tissue;

generating an electrical signal from a power source to a pair of circumferentially spaced electrodes disposed in an interlocking configuration on the antenna assembly;

generating a feedback signal in response to the electrical signal, the feedback signal depending on the proximity of tissue relative to a longitudinal space defined between the electrodes;

comparing the feedback signal to a predetermined parameter;

determining an insertion depth of the antenna assembly relative to tissue based on the comparison; and

controlling delivery of energy from the power source to the antenna assembly for application to tissue based on the comparison.

10. The method according to claim 9, wherein the predetermined parameter of the comparing step is a predetermined range of impedance values.

11. The method according to claim 9, further comprising sensing impedance between the pair of electrodes prior to generating the feedback signal, wherein the feedback signal is based on the sensed impedance.

12. The method according to claim 9, wherein controlling delivery of energy from the power source further includes one of preventing or initiating the delivery of energy from the power source to the antenna assembly based on the comparison.

13. A microwave antenna assembly, comprising:

an antenna configured to deliver microwave energy to tissue, the antenna including an inner conductor, an outer conductor and an inner insulator disposed therebetween; and

a pair of electrodes disposed on the antenna and circumferentially spaced relative to each other in an interlocking configuration to define at least one longitudinal space therebetween, the pair of electrodes configured to be positioned relative to tissue upon insertion of the antenna into tissue, at least one of the electrodes configured to receive an electrical signal and generate a feedback signal in response thereto, the feedback signal corresponding to the proximity of tissue relative to the at least one longitudinal space and configured to be compared to at least one predetermined parameter to determine a depth of the insertion of the antenna into tissue.