RF energy console including method for vessel sealing

Patent metadata

Field	Value
Publication number	US-9161813-B2
Application number	US-201313911673-A
Country	US
Kind code	B2
Filing date	Jun 6, 2013
Priority date	Jul 20, 2012
Publication date	Oct 20, 2015
Grant date	Oct 20, 2015

Abstract

A RF energy console controls RF energy output from a RF generator for sealing blood vessels. The energy console includes a processor that executes routines and a controller feedback circuit that, in combination, control the RF generator. Operation includes a heating stage outputting a RF ramping voltage and determining a decrease in measured current to less than a predetermined % percentage of a maximum measured and stored current value to advance to a sealing stage. Then, the voltage is controlled to maintain an increasing change in impedance until a change in current value approaches a flat curve indicating seal completion, which stops the RF generator output. To reseal or enhance a blood vessel seal, the energy console executes the same routines as in the initial sealing operation.

First claim

What is claimed is:

1. A method of sealing at least one of a blood vessel and tissue by controlling electrosurgical energy provided by an electrosurgical radio frequency (RP) energy console to a handpiece comprising the steps of:
(1) in response to actuation by a user, executing a heating stage, the heating stage including (a) outputting and applying an increasing RF ramping voltage to the handpiece for heating fluid in the at least one of the blood vessel and the tissue; (b) measuring a current (I meas ) value for the electrosurgical RE energy console; (c) comparing the current (I meas ) value with a stored maximum current (I max ) value; (d) updating the stored maximum current (I max ) value to the current (I meas ) value and returning to step (b) when the current (I meas ) value is greater than the stored maximum current (I max ) value; (e) determining whether the current (I meas ) value is less than a single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value and returning to step (b) when the current (I meas ) value is greater or equal to the single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value; and (f) when the current (I meas ) value is less than the single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value resulting from onset of boiling of the fluid in the at least one of the blood vessel and the tissue, advancing from the heating stage to a sealing stage;
(2) the sealing stage including (a) outputting a sealing voltage from the electrosurgical RF energy console to the handpiece and (b) adjusting the sealing voltage to maintain an increasing essentially constant predetermined change of impedance (ΔZ seal ) value.

2. The method according to claim 1 , wherein the step of (2)(b) adjusting the sealing voltage that is output from the electrosurgical RF energy console to maintain the increasing essentially constant predetermined change of impedance (ΔZ seal ) value comprises the steps of:
(i) measuring a voltage (V meas ) value and the current (I meas ) value of energy output by the electrosurgical RF energy console a plurality of times to thereby measure a plurality of voltage (V meas ) values and a plurality of current (I meas ) values;
(ii) storing the plurality of the voltage (V meas ) values and the plurality of current (I meas ) values;
(iii) calculating a change of current (ΔI calc ) value essentially from the plurality of current (I meas ) values stored in step (2)(b)(ii);
(iv) calculating a change of impedance (ΔZ calc ) value essentially from the plurality of voltage (V meas ) values stored in step (2) (b) (ii) and the plurality of current (I meas ) values stored in step (2)(b)(ii);
(v) adjusting the sealing voltage that is output by the electrosurgical RF energy console so that the change of impedance (ΔZ calc ) value essentially equals the increasing essentially constant predetermined change of impedance (ΔZ seal ) value;
(vi) determining to return and returning to step (i) when an absolute value of the change of current (ΔI calc ) value is essentially greater than an absolute value of a predetermined change of current (ΔI shutoff ) value; and
(vii) stopping the sealing voltage that is output from the electrosurgical RF energy console to power the handpiece when the absolute value of the change of current (ΔI calc ) value is essentially less than the absolute value of the predetermined change of current (ΔI shutoff ) value.

3. The method according to claim 2 , wherein the predetermined change of current (ΔI shutoff ) value comprises a single value between about −20 mA/second and about −80 mA/second, and wherein the single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value is between about 40% and about 90%.

4. The method according to claim 2 , including the electrosurgical RF energy console reading the predetermined change of current (ΔI shutoff ) value for the sealing stage from a handpiece memory that is provided with a cable of the handpiece, the method including the step of, during the sealing stage, stopping output of the sealing voltage from the electrosurgical RF energy console when the absolute value of the change of current (ΔI calc ) value is less than the absolute value of the predetermined change of current (ΔI shutoff ) value before a predetermined sealing error time limit expires.

5. The method according to claim 4 , including the following steps carried out by the electrosurgical RF energy console:
reading the increasing RF ramping voltage and a predetermined current limit value from the handpiece memory; and
reading the single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value from the handpiece memory.

6. The method according to claim 2 , further comprising the steps of:
during the heating stage, stopping the increasing RF ramping voltage output from the electrosurgical RF energy console after a predetermined heating error time limit when the current (I meas ) value is not determined to be less than the single predetermined current threshold percentage (% th ) value of the stored maximum current (I max ) value before the predetermined heating error time limit expires; and
during the sealing stage, stopping the sealing voltage output from the electrosurgical RF energy console when the absolute value of the change of current (ΔI calc ) value is less than the absolute value of the predetermined change of current (ΔI shutoff ) value before the predetermined heating error time limit expires.

7. The method according to claim 2 , including the step of resealing the at least one of the blood vessel and the tissue by repeating the steps (1)(a)-(f) and (2)(a)-(b)(i)-(vii) in response to a reseal activation by the user of the electrosurgical RE energy console, wherein the resealing activation operates in the same manner as the sealing stage.

8. The method of claim 2 , wherein the predetermined change of current (ΔI shutoff ) value during the sealing stage comprises a single value between about −20 mA/second and about −80 mA/second.

9. The method according to claim 1 , including the step of identifying the handpiece connected to the electrosurgical RF energy console and providing the increasing RF ramping voltage as a predetermined start-up increasing voltage ramping value corresponding to the handpiece and providing the single predetermined current threshold percentage (% th ) value of the stored maximum current (I max ) value that is between 40% and 90% as a percentage value corresponding to the handpiece.

10. The method according to claim 1 , including comparing the current (I meas ) value with a predetermined stored current limit value and limiting current that is output by the electrosurgical RF energy console when the current (I meas ) value essentially equals the predetermined stored current limit value.

11. The method according to claim 1 , wherein the heating stage includes the step of discontinuing output of the increasing RF ramping voltage from the electrosurgical RF energy console after a predetermined heating error time limit when the current (I meas ) value is not less than the single predetermined current decrease threshold percentage (% th ) value of the stored maximum current (I max ) value before the predetermined heating error time limit expires.

12. The method according to claim 11 , including the step of reading the predetermined heating error time limit from a handpiece memory.

13. The method of claim 1 , wherein the

Assignees

• Benamou Steffan
• Stryker Corp

Inventors

• Benamou Steffan

Classifications

• A61B2018/00666

  using a threshold value · CPC title

• A61B2018/00702

  Power or energy · CPC title

• A61B2018/0063

  Sealing · CPC title

• A61B2018/00678

  upper · CPC title

• A61B18/18 Primary

  by applying electromagnetic radiation, e.g. microwaves · CPC title