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Energy options in gynecologic surgery

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And, of course, the Harmonic Ace device has nothing to do with electricity, and I want to dispel that right away. Harmonic energy has to do with mechanical energy. It’s very different.

And here, we have high-frequency ultrasound in tissue creating a number of predictable events. And the most predictable event is that it basically denatures proteins by deconfiguring them, by breaking up the hydrogen bonds that keep their structure, and they get denatured—a very low temperature phenomenon. And, ultimately, if you have ultrasound and tissue you form steam—and, remember, steam is percussive, you can’t take that away from steam. And steam that’s in the tissue will start to cavitate it and it will make it fragment, and that’s what’s called cutting. Ultrasonic energy attains cutting by cavitational fragmentation of tissue with the production of steam from high-frequency ultrasound.

This is the anatomy of a Harmonic Ace. And we have a tissue-holding device on top, which is plastic, nonmoving, nonthermal. And we have a blade that’s oscillating 55,500 times a cycle. Think about how low-frequency this is. You can use 3 million cycles per second when you’re doing ultrasound, vaginal ultrasound in the office. This is 55,500 times a cycle. And that’s also why it has such thermal effects.

And you can vary how far this blade goes out per cycle. And that’s what’s called your levels. And, in fact, this has nothing to do with power; it has to do with how much your blade comes out per cycle, which is called excursion. And, essentially, a Harmonic scalpel…you can see how different settings—you know, I’ll just run that through again, settings 1, 2, 3, 4, 5—affect how far the blade comes out per cycle. And as a result of this, since the energy that’s being produced is being delivered in the same amount of time, whether you come out a short distance or a long distance, you can predict the following algorithm based on those excursions. In general, if you want to coagulate with a Harmonic ACE, you want to be in the lowest setting so the energy is delivered over the smallest surface area, which is the smaller blade excursion. And on the other hand, just the opposite—if you want to cut, you’re obviously going to just use the opposite algorithm, and you’re going to want to have the largest surface area with the same amount of energy, and that’s going to promote cutting. So our variable features on the Harmonic scalpel totally relate to what we intend on doing—or not doing—with our Harmonic ACE.

Now, what’s really different to me between ultrasonic energy and thermal energy from electrosurgery is the volumetric spread of energy. So let’s take a look at the Harmonic scalpel. Remember, it’s an ultrasound, it’s a blade that’s oscillating 55,500 times a second. Where’s most of the energy? It’s at the tip of the instrument, in fact, and the most active portion of a Harmonic scalpel is at the tip of the blade because it is linearly propagating. As a result, the lateral margins are that much smaller because you don’t have the propagation of energy in an ellipsoid 3-dimensional fashion as you do with electrosurgery. It also makes your thermal margins much more predictable.

And so, of course, what we do is we make sure, as I told you, low-energy devices—we’re getting back to that central principle—low-energy devices get the best hemostasis based on our vessel compression. You want to release tension. So when you do the Harmonic ACE for vessels, you grasp, you release tension, you then desiccate. And then, after you see the visual signs of desiccation—which, of course, is a plume of steam—you now will wait, let the cutter curve, and then you will remove. And you always remove in a linear fashion in the same track that you applied your device.

So I want to finish up and thank you for being here today. I hope that was helpful for all who might want to know more about electrosurgery, ultrasonic energy, to remind you and myself that it really has nothing to do with the wand, and it has to do with the mirror and my understanding of fundamentals of electricity and ultrasonic. And it’s really up to you, it’s not up to the wand. And I’d be more than happy to take any questions or comments from anybody here who’s been nice enough to listen to today’s talk. Okay, thank you very much.

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