The present invention relates surgical instruments and, more specifically, to an electrosurgical vessel sealing device controller that can produce repeatable seals in blood vessels and other tissues.
Electrosurgical vessel sealers are surgical instruments that are used for the occlusion of blood vessels and halting of bleeding during surgical procedures. The electrodes of the vessel sealer are carried by a pair of opposing jaws and interconnected to an electrosurgical generator that can selectively supply radiofrequency (RF) energy to the electrodes. A user may close the jaws around a vessel to be sealed by squeezing a lever associated with a handle assembly. The vessel may then be sealed by supplying the RF energy to the clamped vessel.
Electrical power control of the vessel sealer is controlled by the electrosurgical generators. Conventional approaches to power control involve the application of power according to a predetermined power curve where power is variably applied to have a particular impact on the tissue to be sealed. Due to the variability of the tissue to be treated, however, these approaches often lack consistent results. Accordingly, there is a need in the art for an electrosurgical vessel sealing device controller that is configured to produce repeatable conditions in the tissue to be treated for consistent results.
The present invention provides an electrosurgical vessel sealing device controller that is configured to provide energy according to a scheme that conditions the tissue to be treated to be homogeneous by pre-polymerizing collagen and then allows rehydration of the tissue prior to the main sealing cycle. More specifically, the present invention includes an electrosurgical system having a vessel sealer having a pair of jaws and an electrosurgical generator coupled to the pair of jaws of the vessel sealer and having a controller configured to output radiofrequency energy to the vessel sealer. The controller is configured to output sufficient radiofrequency energy in a first stage at a first power level until a first stopping point, to interrupt the output of sufficient radiofrequency energy in a second stage for a predetermined period of time, and to output sufficient radiofrequency energy in third stage at a second power level to cause sealing of the tissue. The stopping point is selected to elevate the temperature of any tissue positioned in the jaws without reaching a full polymerization temperature where any collagen and elastic in the tissue will fully polymerize. The stopping point may be selected according to the tissue achieving a minimum impedance for a minimum amount of time, the tissue reaching a predetermined impedance measured after a fixed amount of time, a fixed amount of time, and a rate of change of impedance of the tissue exceeding a threshold. The predetermined period of time of the second stage may comprise a fixed duration. The predetermined period of time of the second stage may comprise a variable duration. The variable duration may be determined based on the amount of time the tissue required to reach the minimum impedance of the first stage or the amount of time for the rate of change of impedance to exceed the threshold in the first stage. The third stage may comprise the output of power at the second power level until the tissue reaches an end point. The third stage may comprise the output of power at the second power level until the tissue reaches an intermediate impedance at a fixed time. The third stage may comprise the output of power at the second power level that is proportional to the time taken to exceed the impedance rate of change threshold from the first stage.
The present invention also includes a method of controlling the power output from an electrosurgical generator to a vessel sealer having a pair of jaws. The method includes the steps of providing the vessel sealer having the pair of jaws, coupling the electrosurgical generator to the pair of jaws of the vessel sealer, and powering the electrosurgical generator to output radiofrequency energy to the vessel sealer in a first stage at a first power level until a first stopping point, to interrupt the output of sufficient radiofrequency energy in a second stage for a predetermined period of time, and to output sufficient radiofrequency energy in third stage at a second power level to cause sealing of the tissue. The stopping point may be selected to elevate the temperature of any tissue positioned in the jaws without reaching a full polymerization temperature where any collagen and elastic in the tissue will fully polymerize. The stopping point may be selected based on the tissue achieving a minimum impedance for a minimum amount of time, the tissue reaching a predetermined impedance measured after a fixed amount of time, a fixed amount of time, and a rate of change of impedance of the tissue exceeding a threshold. The predetermined period of time of the second stage may comprise a fixed duration. The predetermined period of time of the second stage may comprise a variable duration that is determined based on the amount of time the tissue required to reach the minimum impedance of the first stage or the amount of time for the rate of change of impedance to exceed the threshold in the first stage.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:
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The first stage implemented by controller 22 comprises an initial conditioning pulse that is configured to elevate the temperature of the tissue to a level above body temperature, but below the full polymerization temperature of the collagen and elastin in the tissue. Polymerization generally starts around 70° C. to 80° C. but can be more readily identified by the change in impedance, which is primarily a factor of the moisture that is being affected by the energy delivery. The amount of moisture can relate to temperature rise as the moisture will evaporate around about 100° C. and there will not be a sharp rise in temperature past that point until the tissue starts to dry out. There is a relationship between the power and time to keep the temperature low and is a function of energy delivery. If the power is higher, the time duration of pre-conditioning phase has to be shorter. For example, pre-conditioning can occur at 40 Watts for 250 milliseconds or 20 Watts for 400 milliseconds (as compared to a sealing stage at 40 W that is greater than 750 milliseconds and provides full polymerization). It should be recognized by those of skill in the art that these amounts are dependent on many factors, such as vessel size. A small vein, for example, can be fully polymerized at 750 ms. A larger artery might take 2-3 seconds. The dimensions of the jaw, jaw pressure and other factors may also be relevant. Nevertheless, in any circumstances, the first stage is unlikely to be greater than 750 ms.
The elevation of temperature while remaining below the polymerization temperature is accomplished by stopping the delivery of energy at one of a number of alternative stopping points before the temperature becomes to high. One acceptable stopping point may comprise the tissue reaching a minimum impedance for a minimum amount of time. The stopping point may instead comprise a predetermined impedance that is measured after a fixed amount of time has elapsed. The stopping point may also comprise a fixed amount of time having elapsed. The stopping point may additionally comprise the rate of impedance change exceeding a predetermined threshold.
After completion of the first stage, controller 22 is configured to implement a second stage where the delivery of energy is interrupted for a predetermined period of time to allow for the rehydration of the tissue. The predetermined period of time may comprise a fixed duration or a variable duration. The variable duration may be determined based on the time that the tissue took to reach the predetermined minimum impedance of the conditioning pulse in the first stage, the particular type of handpiece being used, or the amount of time for the rate of impedance change to exceed the predetermined threshold in the first stage.
After completion of the second stage, controller 22 is configured to implement a sealing cycle. For the sealing cycle, power is applied according to a conventional load curve to a second power level that is greater than the first power level and energy is delivered until the tissue reaches a desired end point. Second power level may be between 40W and 50W. Alternatively, power may be applied according to a conventional load curve to a second power level that is greater than the first power level until the tissue reaches an intermediate impedance at a fixed time. The energy delivery may then be decreased (“stepped down”) to a third power level, such as 30W, hat is lower than the second power level and applied according to a third load curve. Energy delivery is then maintained until the tissue reaches a desired end point. Finally, power may be applied at a power level that is proportional to the time taken to exceed the impedance rate of change threshold from the first stage, such as between 30W and 100W.
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As described above, the present invention may be a system, a method, and/or a computer program associated therewith and is described herein with reference to flowcharts and block diagrams of methods and systems. The flowchart and block diagrams illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer programs of the present invention. It should be understood that each block of the flowcharts and block diagrams can be implemented by computer readable program instructions in software, firmware, or dedicated analog or digital circuits. These computer readable program instructions may be implemented on the processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine that implements a part or all of any of the blocks in the flowcharts and block diagrams. Each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that each block of the block diagrams and flowchart illustrations, or combinations of blocks in the block diagrams and flowcharts, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.
The present application claims priority to U.S. Provisional No. 62/970816, filed on Feb. 6, 2020, which is hereby incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/016798 | 2/5/2021 | WO |
Number | Date | Country | |
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62970816 | Feb 2020 | US |