Methods and systems for advanced harmonic energy

Patent metadata

Field	Value
Publication number	US-11344362-B2
Application number	US-201916531591-A
Country	US
Kind code	B2
Filing date	Aug 5, 2019
Priority date	Aug 5, 2016
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

Aspects of the present disclosure are presented for a medical instrument configured to adjust the power level for sealing procedures to account for changes in tissue impedance levels over time. In some aspects, a medical instrument may be configured to apply power according to a power algorithm to seal tissue by applying a gradually lower amount of power over to time as the tissue impedance level begins to rise out of the “bathtub region,” which is the time period during energy application where the tissue impedance is low enough for electrosurgical energy to be effective for sealing tissue. In some aspects, the power is then cut once the tissue impedance level exceeds the “bathtub region.” By gradually reducing the power, a balance is achieved between still applying an effective level of power for sealing and prolonging the time in which the tissue impedance remains in the “bathtub region.”

First claim

The invention claimed is:

1. A surgical system, comprising:
an end effector comprising an energy delivery component configured to transmit electrosurgical energy to tissue; and
a control circuit, configured to:
cause the energy delivery component to apply preliminary power to tissue;
measure impedance of the tissue;
determine a minimum tissue impedance;
compare the minimum tissue impedance to a plurality of tissue impedance thresholds, wherein a plurality of different load curve profiles are associated with the plurality of tissue impedance thresholds;
set a load curve based on the comparison matching with one of the plurality of different load curve profiles, and the load curve comprises a maximum power value, a transition tissue impedance threshold, and a termination tissue impedance threshold; and
set a value for the maximum power value, the transition tissue impedance threshold, and the termination tissue impedance threshold, wherein the transition tissue impedance threshold is a function of the minimum tissue impedance, and wherein at a tissue impedance value greater than the transition tissue impedance threshold, electrosurgical energy has an insubstantial impact on the tissue;
determine that the impedance of the tissue changes from an initial level to a predetermined proportion of the transition tissue impedance threshold; and
for an application period, cause the energy delivery component to start from the predetermined proportion of the transition tissue impedance threshold and decrease the electrosurgical energy at a steady taper down rate from a first power level until a second power level on the load curve is reached, wherein the steady taper down rate extends a period of time where the tissue is sealed with an amount of energy that does not cause unwanted damage to the tissue, and wherein the steady taper down rate is a gradual rate of change over time until the second power level on the load curve is reached.

2. The surgical system of claim 1 , wherein the plurality of tissue impedance thresholds comprises a first tissue impedance threshold and a second tissue impedance threshold.

3. The surgical system of claim 2 , wherein:
at the minimum tissue impedance that is below the first tissue impedance threshold, the load curve comprises a low minimum tissue impedance profile;
at the minimum tissue impedance that is above the first tissue impedance threshold and below the second tissue impedance threshold, the load curve comprises a medium minimum tissue impedance profile; and
at the minimum tissue impedance that is above the second tissue impedance threshold, the load curve comprises a high minimum tissue impedance profile.

4. The surgical system of claim 1 , wherein the transition tissue impedance threshold is defined as a predetermined amount greater than the minimum tissue impedance.

5. The surgical system of claim 1 , wherein the control circuit is further configured to cause the energy delivery component to apply subsequent power to the tissue based on the load curve.

6. The surgical system of claim 5 , wherein the control circuit is configured to initially apply the first power level at the maximum power value.

7. The surgical system of claim 6 , wherein the control circuit is configured to terminate the subsequent power at the termination tissue impedance threshold.

8. A surgical system comprising:
an end effector comprising an energy delivery component configured to transmit electrosurgical energy to tissue; and
a control circuit operably coupled to the energy delivery component, wherein the control circuit is configured to:
determine an initial tissue impedance;
determine a transition impedance threshold level as a function of the initial tissue impedance, and wherein at a tissue impedance value greater than the transition impedance threshold level, electrosurgical energy has an insubstantial impact on the tissue;
determine that a tissue impedance changes from the initial tissue impedance to a predetermined proportion of the transition impedance threshold level, wherein the transition impedance threshold level is less optimal for tissue sealing at a first power level; and
for an application period, cause the energy delivery component to start from the predetermined proportion of the transition impedance threshold level and decrease the electrosurgical energy at a steady taper down rate from the first power level until a second power level is reached, wherein the steady taper down rate extends a period of time where the tissue is sealed with an amount of energy that does not cause unwanted damage to the tissue, and wherein the steady taper down rate is a gradual rate of change overtime until the second power level is reached.

9. The surgical system of claim 8 , wherein the application period comprises a point in time where the tissue impedance rises above a minimum impedance value in the tissue.

10. The surgical system of claim 9 , further comprising a sensor configured to measure the minimum impedance value in the tissue.

11. The surgical system of claim 8 , wherein the energy delivery component is configured to transmit RF and ultrasonic energy.

12. The surgical system of claim 8 , wherein the application period is a first application period, wherein the control circuit is further configured to, for a second application period, cause the energy delivery component to reduce the second power level to a third power level.

13. The surgical system of claim 12 , wherein the second application period comprises a point in time where the tissue impedance rises above the transition impedance threshold level.

Assignees

• Ethicon Llc
• Cilag Gmbh Int

Inventors

• Yates David C
• Krumm Amy M
• Davison Mark A

Classifications

• A61B17/320092

  with additional movable means for clamping or cutting tissue, e.g. with a pivoting jaw · CPC title

• A61B2018/00994

  combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound · CPC title

• A61B2018/0063

  Sealing · CPC title

• A61B18/1482

  having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy · CPC title

• A61B2018/00702

  Power or energy · CPC title