Thank you, Dr. Chae for this talk. So it's very last minute, but hopefully we can get through this, yeah. Okay, so today I'm going to talk about monopolar electrosurgery. So I know that this may not apply to all of you, but as a surgeon, I think this is a very important concept that we need to know when we do surgery. So first of all, I would like to acknowledge Ethicons Johnson & Johnson, because most of this material, the teaching materials are provided by them. And in fact, this talk is a part of a seminar on science of energy. But today we're just going to talk about monopolar surgery, electrosurgery, yeah. So this is the content of my talk. So a little bit of introduction, very, very brief physics of electricity, and then principles of monopolar electrosurgery, and then potential risks of it. Okay, so let's start with introduction. So we know that the basics of surgery is to remove, replace, repair, and reorganize tissue. So it's a balance between cutting and hemostasis. And in most of our surgery, we need to think about efficiency of our surgery. So that means the faster we can finish our surgery, the more efficient we can be. But so this is when the cutting and hemostasis comes in. So if we have an instrument that can do both cutting and hemostasis at the same time, we can increase our efficiency in surgery. Okay, so have you ever wondered why patients don't get electrocuted during surgery? Okay, so this is electrosurgery, monopolar, and it's just buzzing on the light bulb, and it didn't get electrocuted. So, yeah, so hold your thought there, and I will come back to these questions later. Okay, and have you ever wondered which monopolar waveform is associated with lower risk of thermal damage, coagulation or cutting? So this is a first waveform, and this is a second one. So you can clearly see which one cause less damage, right? And which one do you think is which? Okay, so you can see that the cutting waveform cause less damage. Okay, so why do we need to have this kind of training? Basically, the recent survey mentioned that the current levels of surgical trainings, the survey showed that nearly 50% did not receive any training in the use of electrosurgery, 64% received no formal training on energy-based instrumentation, and surgeons scored a mean of 55% on an exam testing critical knowledge of electrosurgery, suggesting that a gap in education and training. Okay, so why is training important? Basically, which increase training and education, it will support, education supports will improve patient's outcome. And this is our goal, right? To improve patient outcome. And if we have lack or mis-education of, or misuse of electrosurgery, it can lead to thermal burns, hemorrhage, fire, death, and you can get litigation with adverse cost. And it has been shown that the training works. Basically, if you do training, the surgeon who have received both in-class and classroom and hands-on training, they have 40% improvement in their knowledge level. Okay, so at the top of the pyramid is our common goal, right? For optimal patient outcome. And so we need to consider many factors. So for example, the human technology, patient factors, and also surgeon factors. And we improve interactions between the devices we use and the tissues, and hopefully we can have optimal patient outcome. So we all know that all these factors are important in the best outcome in surgery. We think about aseptic technique, tissue compression, tissue tension, tissue dynamics. Hopefully we can create minimal tissue injury to have tissue repair and then hemostasis. So if we go back to our early preclinical years, I'm sure you know about the principles of hemostasis with the coagulation cascade. So just within minutes of the surgery, we have vessel constrictions, platelet adhesions, aggregations, and then there'll be platelet hemostatic and there'll be mixed platelet and fibrin forms. And then within hours, there'll be fiber clots and these clots will undergo retractions. And then within days you will have recanalization. So I'm sure for those surgeons, you have many, many medical devices that can help augment hemostasis. So you can have tissue compressions, so you can use sutures, staples, and so on. You have topical hemostatic agents like surgery cells, you can use flow seals and so on. And I think we are very lucky nowadays. We have so many energy modalities to choose from for our surgery. We can use electrosurgery like monopolar, bipolar, we have advanced bipolar nowadays and we have lasers and so on. And I'm sure when you think about characteristic of ideal energy devices, you will be thinking about all these factors. It has to be ergonomic, multifunctional, it has to be safe, cost-effective, easy to use, precise. It should be able to deliver reliable coagulation, producing minimal tissue injury, minimal charring and improve visibility. So I'm sure we all think about these when we choose ideal energy device. Okay, so let's move to physics of electricity, but don't worry, I'm not going to go into very, very details just very, very basic principles. So I'm sure we all know electricity, it always takes the path of least resistance, it always seeks ground and it must have a complete circuit to work. Okay, so we have two kinds of circuits, we have DC and AC. So for DC is basically the battery, right? And then in the everyday life we use is the alternating current, AC. In our household electricity and certainly for the monopolar or bipolar surgery we use, we use alternating current. And this is to answer the previous questions, why don't patient get electrocuted when we use electrosurgery? And this is the reason, most electrosurgery is in the range of 200 kilohertz and anything that is below 100 kilohertz, there is no neuromuscular stimulation. So it's difference when you are talking about household appliance that it's around 60 hertz that will cause neuromuscular stimulation so you can get electrocuted, okay? So hopefully that will answer the previous questions. Okay, and then back to the secondary year, maybe air levels, we're talking about physics here and I'm sure you remember the Ohm's law, so V equals to IR. So if I just use this car and the hill to demonstrate a little bit about physics. So when this car need to go up the hill, it will have more resistance, right? So then it will need more voltage which is the driving force to go up the hill. So if you want to have the same speed, so you will need more voltage or driving force. And when the car goes down the hill, there will be less resistance, right? Then to maintain the same speed, it will need to reduce the voltage or the driving force. And we know that power is equal to the energy or heat produced or used over the period of time, okay? So, and the very, very last slide about physics. So in terms of current concentration, we know that the tissue damage is proportional to the power applied to the area of contact. So for example, if we use the needle diatomy, it has very, very small surface area, right? So you will create more tissue damage. So this is compared to if you use ball diatomy or needle diatomy, it has more surface area and so it will have less tissue damage. Okay. So now we move on to the principles of monopolar surgery. So that is all I'm going to mention about physics now. Okay, so hopefully these are more relevant to the surgeon. So as I mentioned just now, the basics of electricity in surgery, it takes the path of least resistance. You will need a constant power variable voltage generators to have electrosurgery. And as I say, the injury is proportional to the current concentration. So I'm sure you have seen these different terms, cautery, electrocautery, electrosurgery. A lot of people use these terms interchangeably, but in fact, it means completely different things. So for example, cautery, it just means surgical use of heat, okay? And then when we talk about electrocautery, it's the process of destroying tissue with an object that is heated with electricity and with electrocautery, there is no current flowing through the patient. So it's just that this device, it's heated up and it's used to destroy tissue. So these are used less commonly in gyne or gyneoncology. So usually electrocautery is used in the office setting, mostly, for example, by the dermatologist, for example, to destroy warts. And then electrosurgery is what we use usually for our everyday surgical practice. So it's a use of alternating current that pass through the patient to coagulate and cut tissue. So the correct term that we should use is electrosurgery. Okay, as I said, for monopolar electrosurgery to work, it needs the currents flows from a small device electrode to and through the patient to a larger in different ground electrode. So I'm sure you know, you will stick a pad on, say most commonly on patient's thigh when you use monopolar surgery. And this pad is used for the return electrode. And the patient is vital in completing this circuit. Okay, another principles, as I say, the electric current follows the path of least resistance. So the conductivity is directionally proportional to the water content of the tissue. Okay, so as the tissue desiccate, so when you burn the, heat up the tissue, the water will evaporate, right? And then you will drive water out of a tissue. So it will dry up the tissue basically. As you do that, there will be increase in resistance. So the electric current will seek an alternate pathway. So it will go to the path of least resistance. So it will go to the path of less resistance. And for, there are two types of monopolar electrosurgery waveform. So I'm sure you're familiar with the cutting. So when you press the yellow button is a cutting and then the coagulation waveform is a blue button. So basically for cutting, it has low voltage, okay? And it's low continuous voltage. So it's 100% on. And then when you look at the coagulation, you have very high voltage, but it's intermittent waveform, okay? Intermittent current. So, and you have something in between that is called blend. So you can set whether it's blend one, 50% cut, 50% on, 50% off. So depending on the tissue effects that you want, you can have various setting on the generator, okay? And so this is to demonstrate the cutting and the coagulation waveform. So this one is cutting the yellow button. You can see the fluorescent light bulb, it lights up continuously. And then for the coagulation, it's, you can see the flickering on the light bulb. So it's like intermittent waveform, okay? So you can see the flickering, right? Okay, so remember. So for cutting waveform, it produced rapid heat and for coagulation, it's reduced producing less heat, okay? Yeah. So we have seen this video just now, basically with coagulation. So which is the first part, you can see more tissue damage compared to the cutting. Okay, so this is coagulation and then this is cutting. Yeah. So you can clearly see the amount of tissue damage is much less with the cutting waveform. Yeah, okay. So how about in terms of death, which one cause more, more death in terms of cut and coagulation? So the first one is coagulation and the second is the cutting. So which one produce more death? Okay, so you can see the coagulation is more shallow compared to the cutting waveform, okay? So the cutting produce more death in terms of tissue. Okay, so a few more terms to be familiarized with regarding monopolar electrosurgery, okay? So you can also have fulguration. It's also known as spray and basically it's a use of high voltage coagulation mode that occurs when tissue is heated above 200 degrees Celsius. So fulguration, it's a non-contact coagulation where the current arcs from the electrode to the tissue and it's similar to lightning moving from cloud to the ground. Because of the high temperature, fulguration causes wide thermal spread and some destruction of the surface level cells. However, it results in the shallow cuts and allows for quick hemostasis over a large area. So for fulguration, we usually use it, for example, during our leap. So after the large loop excision of transformation zone, for example, for cervical dysplasia, then we will use fulguration using a ball diatomy for coagulation. So with the ball diatomy, you don't come into contact with the tissue. So you just remove it slightly and then you activate and then it's basically you can achieve hemostasis without the ball diatomy being in contact with the tissue. And another example that we sometimes use fulguration is that when we have tear on the liver or the spleen surface. So basically you put up the voltage to higher. So usually the setting that you use when you use monopolar is around, you know, 25 to 30. Some people use 35, but when you use fulguration, you need to increase it to 50 or 60 and then it can produce this hemostasis effect. Yeah. And then desiccation is another tissue effects that you can have. It applies a low current and relatively high voltage over broad areas. And desiccation is a form of direct contact coagulations. And the electrode is held against the tissue that occurs around 90 degrees Celsius. It evaporates the water from the cells resulting in cells shrinkage. So with desiccation, it results in a deeper necrosis and thermal spread compared to fulguration because the electrical energy is converted into heat inside the tissue. And then you have vaporization. So this is mostly the cutting effects that you see. So it's a rapidly heats tissue up to 100 degrees Celsius. And this rapid heating causes the cells to vaporize and the steam generated explode the tissue cells resulting in the cutting effects. So vaporizations yield minimal thermal spread allowing collateral tissues to remain healthy during dissection. So vaporization is basically when you use the cut waveform. Okay, so in summary, the cut waveform is a gentler waveform because it has lower voltages, it has less capacitance, less spark travel distance and less temperature. So as much as possible, you should use cutting waveform. Yeah, so as I mentioned just now, the current concentration is equal to current density and the tissue damage is proportional to the power applied to the area of contact. So if you have this needle diatomy, it has less surface area, right? So you will produce more tissue damage. And then if you compare it to the pads that you apply on the tie, it has large surface area. So the return electrode, if it's applied properly because of the large contact area, you don't burn the patient or you don't cause much tissue damage because of the large surface area, okay? And this is a demonstration to show current concentration. So you apply the monopolar onto the sausage and you can see that the current can travel down. And if you have very narrow tissue, it can cause the tissue to heat up and then cause tissue damage, okay? So this is just to demonstrate that the narrower the tissue damage, then you have concentration of current on that small tissue area. And this can produce a lot of heat and then cause tissue damage. So sometimes if you're operating, okay, yeah. So this is the example. So for example, if you're doing a polycystectomy, for example, and you are dividing an adhesions higher up, and because of the current concentration, it can increase the current density and produce tissue damage or inevitable injury to the tissue nearby, okay? So be very careful of this, right? And then, of course, the current concentration depends on many, many factors. So for example, there are different variables that impact on the tissue effects. So for example, the power setting. So I don't know what power setting you use when you use your monopolar or bipolar diatomy. You know, I guess it's like 30, 35, maybe 40, but actually if you try, you know, of course it depends on the different generator, you know, different generator have different setting. But generally, I think you can try to use a lower power setting like 20, 25. I find that it's usually enough when you do, especially when you do open surgery, laparotomy, yeah. So, and it also depends on the different waveform that you use, you know, cutting, blend, or coagulation, and also size of the instrument tips, the technique you use, the time that you apply on the tissues, and of course the tissue variables. So for example, with different patient characteristics, whether it's you're operating on an adult, child, male, female, there is a different water content. And also different tissue properties also have different water contents. For example, if you have edematous tissues, or if you have adipose tissues, then all these will affect the current concentration. Let me just go back, okay. So for this video, it's basically demonstrating the difference between using the pencil and the needle. So this is a pencil. So it's a larger surface area. And the second one, this one, is using the needle diatomy, okay. So you can see that with needle diatomy, it produce more tissue damage because there's less surface area. Yeah, so basically monopolar electrosurgery is effective of, it provides reliable hemostatic control for vessels of one mm or less. But of course, you can increase this hemostatic control by compressing the vessel with an instrument. For example, you can use DeBakey to pick up the bleeding vessels, or you can use like Afri Hemostat to pick up the bleeding vessels, and then you touch the instrument with your diatomy. So usually you should use cutting coagulation to touch the instrument, okay. So you should use the cut coagulation to touch your instrument to achieve this hemostatic control. Okay, so now we move on to the potential risk of monopolar surgery. Okay, so all these are potential risks of monopolar surgery, and we will go through it one by one. So first of all is return electrode failure. You can have direct coupling, capacitance coupling, insulation failure, and even surgical fires. So first we talk about isolation failure. So, but nowadays with technology improvement, so we have isolated generators, the risk of having return electrode failure is much less. So nowadays when you apply the pad on the patient, and for whatever reason, if the pad come off partially or completely, the generator will stop working. So if you suddenly operating and suddenly the generator stop working, then you should check on the pad whether it has been detached. And you need these complete cycles to work for your monopolar to work. Okay, so as I said, you know, if you apply the pad correctly, then you will have less injury. So if you have, the reason is that if you have incorrect application of the pad, you can see the surface area that is in contact with the patient is much less, right? And this will increase the current concentration, and then you can have injury or pad side burn because of this. So be very careful. Okay, so this video is to illustrate pad side burn. So, yeah. So for example, this lemon is the patient and then you apply the monopolar. And then if you have less tissue contact, you can see there is a spark, okay? Between the lemon and the, so the patient and the pad, okay? So that's why you need good contact with the patient to prevent this pad side burn. Okay, so I hope you can see the sparks. Okay. So, yeah. So all manufacturers uses a return electrode as a resistor. And the current from the patient to the pad can cause the pad to become warm. So if you have poorly affixed return electrode, so if you don't apply the pad properly, that will increase the current buildup and heat buildup. So then you can have a pad side burn, okay? So one of the, yeah. So one of the things that they have done to improve or to reduce the risk of pad side burn is using a reusable patient return electrode. So I don't know if you have seen this before, you know, like for example, for Eticon, they have this Megadyne Megasoft patient electrode, but there are others that are produced by other company. And basically this function as a parallel plate capacitor. So the patient and the conductive mesh is embedded in the pad, form the parallel plate capacitor. So. Yeah. So instead of relying on the pad, the patient lie on this, like a gel form, okay? And the return is much bigger surface area in terms of the return electrode. And so sometimes when you're operating and the nurses tell you, or the patient doesn't need a return electrode, it's because of the, they often use this, this, yeah, sorry. The reusable patient return electrode. Basically they lie on it instead of just a small pad on their thigh. Okay. So let's go through a few other things that can happen with monopoly. So have you ever been burned by a monopolar electrosurgery? Okay. I'm sure all of us who operate enough has been burned by a monopolar electrosurgery before, right? So you can see that this, in this video, the person is not wearing any glove, but why didn't he get, didn't he get burned? Okay. So this is direct coupling. Okay. So why didn't this person get burned? Oh, yeah. Okay. So it's because of the surface area. So you can see that he's holding the hemostat with his five fingers instead of just two fingers. So if you use, apply larger surface area to the hemostat, then it will reduce the current concentration. And so you will not get burned. Okay. So when you use a hemostat to burn or to coagulate a tissue, make sure you hold your instrument like this, then it will reduce the risk of burn injury to yourself. Okay. And then there is, so with direct coupling, there is also unintended coupling. So for this video, I'm sure you have used this before, right? So you press on the tissue and for example, you ask your assistant to touch the hemostat to achieve a hemostasis. But with this, you can also cause unintended tissue damage. Okay. So you can see for the second video, you can have unintended tissue damage to the staple line. So you can inevitably cause tissue damage. Okay. And another potential risk is stray current. Okay. So you can see that he's activating with the left hand. Okay. And again, this electrode is not connected to anything, but you can see the spark there. It's because of stray current. Okay. Yeah. And then for the second one, the video in the middle. Okay. So how many of you have seen the nurses do this? They curl the wire onto an instrument and then to prevent the instrument from dropping off. Never, never do this, because you can see that if you activate your monopolar in the air, it can cause spark. So this is because of stray current. Okay. And then again, with the last video, the fluorescent light bulb, you can see if you curl the wire around the fluorescent bulb and you activate the monopolar in the air, it can cause the light bulb to light up. You see? Okay. So it's very dangerous. So try not to activate the monopolar in the air like this, because you can cause stray current and also don't wrap the wire onto an instrument. So nowadays what we do is we just use tape to tape it down to the drapes of the patient. Okay. And then we have a capacitive coupling. So this is more applicable in laparoscopic surgery. So for the first video, let me just stop it first. So for example, the capacitance is basically, it's a stored electrical charge and the capacitor consists of two conductors of different electrical potential separated by an insulator. So let's start this again. So if you have two laparoscopic instruments, okay, and then the one on the right hand, okay, you activate it and you are operating, for example. And then if you have another instrument that is touching the active instrument, you can see that even though it's not on the active part, it can cause sparks at the end. Okay. You can see the sparks there. Yeah. So this is capacitance coupling. Okay. And then the second one is capacitance coupling with the plastic trocar. Okay. So if you activate, you can see it's working. Oh, sorry. Yeah. Okay. And then you can have electrical charge stored in the plastic trocar. And then if you touch a tissue on it, okay, you activate and then you can see that because of stored electrical charge, you can have sparks, okay, in the unintended places. Okay. So, and then even with the metal trocar, this can also happen. okay and then if you activate just the touching with the metal choker see you can see the spark there also okay so again this is capacitance coupling so be very careful with monopolar electrosurgery you can have injuries to in places that you may not be aware of okay so capacitive coupling is more of a problem if you do single site surgery or single port surgery so 18% of general and gynae surgeons who perform single site surgery has experienced visceral burns and monopolar surgery is associated with inherent risk and complications caused by this inevitable direct or capacitive coupling or insulation failure of instrument and the proximity and crossing of multiple instruments generate capacitive or direct coupled currents which may cause visceral burns okay so and next is insulation failures so it can be caused by repeated sterilizations electrical heating or even manufacturing defects and the smaller the defects the greater the likelihood of the injury okay so we have seen this video just now it's okay I'll skip that so and another risk is surgical fires it's not known how many cases of surgical fires are there but in US there is a study that showed that around 20 to 30 cases of surgical fires are disabling and 1 to 2 are fatal and in 70% of surgical fires the electrosurgical equipment provides the ignition okay so remember the fire triad you need an oxidizer you need an ignition source and a fuel and if you have all these trees then you can cause a fire so be very careful okay so if you encounter surgical fires if it's a non airway fire then you should turn off the gas remove all burning material you should use the co2 extinguisher and then care for the patient and of course if you're airway fire which is more common in neck and head and neck in procedures okay then you should remove the endotracheal tube immediately and then stop the gases okay so for safe use of monopolar electrosurgery it's it's better to consider using cut waveform most of the time and then you can use lowest setting lowest power setting for desired tissue effects so you can try at a lower setting like 25 30 and then if it doesn't do the desired doesn't cause the desired tissue effect then you can always increase it to like 30 35 and so on okay so you should always check the insulation of all the instrument and the connectors before use but usually for us this is you usually done by the nurses and we should use isolated generator and the patient contact quality monitoring systems to prevent pet sideburn and if possible we can use the parallel plate capacitor like the pad and the things that we should avoid is avoid an open circuit so next time when you want to try whether the monopolar work don't just activate it in the air okay this is very dangerous try to activate it on the tissue okay so this will limit activation with electrode off the tissue and then it will limit the direct coupling and if you have a very very charred instrument you should clean it before use and avoid inevitable metal to metal contact if possible okay so as I say there is I think in surgery there is no single energy modality that is right for one single procedure so you should choose the right energy for the right job okay so that's all from me so I'm happy to take any questions if there is any

monopolar electrosurgery

surgical practice

hemostasis

electrosurgery risks

Ohm’s Law

return electrode

waveforms

patient safety