Electrosurgery Part II. Technology, applications, and safety of electrosurgical devices Arash Taheri, MD,a Parisa Mansoori, MD,b Laura F. Sandoval, DO,a Steven R. Feldman, MD, PhD,a,b,c Daniel Pearce, MD,a and Phillip M. Williford, MDa Winston-Salem, North Carolina CME INSTRUCTIONS The following is a journal-based CME activity presented by the American Academy of Dermatology and is made up of four phases: 1. Reading of the CME Information (delineated below) 2. Reading of the Source Article 3. Achievement of a 70% or higher on the online Case-based Post Test 4. Completion of the Journal CME Evaluation

Learning objectives After completing this learning activity, participants should be able to compare and contrast electrosurgery with other surgical methods; describe the different technologies used in different electrosurgical units for controlling the output power, tissue effect, and patient and operator safety; and delineate the contraindications and limitations of electrosurgery.

CME INFORMATION AND DISCLOSURES Statement of Need: The American Academy of Dermatology bases its CME activities on the Academy’s core curriculum, identified professional practice gaps, the educational needs which underlie these gaps, and emerging clinical research findings. Learners should reflect upon clinical and scientific information presented in the article and determine the need for further study.

Date of release: April 2014 Expiration date: April 2017

Target Audience: Dermatologists and others involved in the delivery of dermatologic care. Accreditation The American Academy of Dermatology is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. AMA PRA Credit Designation The American Academy of Dermatology designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditsÔ. Physicians should claim only the credit commensurate with the extent of their participation in the activity. AAD Recognized Credit This journal-based CME activity is recognized by the American Academy of Dermatology for 1 AAD Credit and may be used toward the American Academy of Dermatology’s Continuing Medical Education Award. Disclaimer: The American Academy of Dermatology is not responsible for statements made by the author(s). Statements or opinions expressed in this activity reflect the views of the author(s) and do not reflect the official policy of the American Academy of Dermatology. The information provided in this CME activity is for continuing education purposes only and is not meant to substitute for the independent medical judgment of a healthcare provider relative to the diagnostic, management and treatment options of a specific patient’s medical condition. Disclosures Editors The editors involved with this CME activity and all content validation/peer reviewers of this journal-based CME activity have reported no relevant financial relationships with commercial interest(s). Authors Dr Feldman is a consultant and speaker, has received grants, or has stock options in Abbott Labs, Amgen, Anacor Pharmaceuticals, Inc, Astellas, Caremark, Causa Research, Celgene, Centocor Ortho Biotech Inc, Coria Laboratories, Dermatology Foundation, Doak, Galderma, Gerson Lehrman Group, Hanall Pharmaceutical Co Ltd, Informa Healthcare, Kikaku, Leo Pharma Inc, Medical Quality Enhancement Corporation, Medicis Pharmaceutical Corporation, Medscape, Merck & Co, Inc, Merz Pharmaceuticals, Novan, Novartis Pharmaceuticals Corporation, Peplin Inc, Pfizer Inc, Pharmaderm, Photomedex, Reader’s Digest, Sanofi-Aventis, SkinMedica, Inc, Stiefel/GSK, Suncare Research, Taro, US Department of Justice, and Xlibris. Drs Taheri, Mansoori, Sandoval, Williford, and Pearce have no conflicts of interest to declare. Planners The planners involved with this journal-based CME activity have reported no relevant financial relationships with commercial interest(s). The editorial and education staff involved with this journal-based CME activity have reported no relevant financial relationships with commercial interest(s). Resolution of Conflicts of Interest In accordance with the ACCME Standards for Commercial Support of CME, the American Academy of Dermatology has implemented mechanisms, prior to the planning and implementation of this Journal-based CME activity, to identify and mitigate conflicts of interest for all individuals in a position to control the content of this Journal-based CME activity.

Ó 2013 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2013.09.055 Technical requirements: American Academy of Dermatology: d Supported browsers: FireFox (3 and higher), Google Chrome (5 and higher), Internet Explorer (7 and higher), Safari (5 and higher), Opera (10 and higher). d JavaScript needs to be enabled. Elsevier: Technical Requirements This website can be viewed on a PC or Mac. We recommend a minimum of: d PC: Windows NT, Windows 2000, Windows ME, or Windows XP d Mac: OS X d 128MB RAM d Processor speed of 500MHz or higher d 800x600 color monitor d Video or graphics card d Sound card and speakers Provider Contact Information: American Academy of Dermatology Phone: Toll-free: (866) 503-SKIN (7546); International: (847) 240-1280 Fax: (847) 240-1859 Mail: P.O. Box 4014; Schaumburg, IL 60168 Confidentiality Statement: American Academy of Dermatology: POLICY ON PRIVACY AND CONFIDENTIALITY Privacy Policy - The American Academy of Dermatology (the Academy) is committed to maintaining the privacy of the personal information of visitors to its sites. Our policies are designed to disclose the information collected and how it will be used. This policy applies solely to the information provided while visiting this website. The terms of the privacy policy do not govern personal information furnished through any means other than this website (such as by telephone or mail). E-mail Addresses and Other Personal Information - Personal information such as postal and e-mail address may be used internally for maintaining member records, marketing purposes, and alerting customers or members of additional services available. Phone numbers may also be used by the Academy when questions about products or services ordered arise. The Academy will not reveal any information about an individual user to third parties except to comply with applicable laws or valid legal processes. Cookies - A cookie is a small file stored on the site user’s computer or Web server and is used to aid Web navigation. Session cookies are temporary files created when a user signs in on the website or uses the personalized features (such as keeping track of items in the shopping cart). Session cookies are removed when a user logs off or when the browser is closed. Persistent cookies are permanent files and must be deleted manually. Tracking or other information collected from persistent cookies or any session cookie is used strictly for the user’s efficient navigation of the site. Links - This site may contain links to other sites. The Academy is not responsible for the privacy practices or the content of such websites. Children - This website is not designed or intended to attract children under the age of 13. The Academy does not collect personal information from anyone it knows is under the age of 13. Elsevier: http://www.elsevier.com/wps/find/privacypolicy.cws_home/ privacypolicy

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Electrosurgical currents can be delivered to tissue in monopolar or bipolar and monoterminal or biterminal modes, with the primary difference between these modes being their safety profiles. A monopolar electrosurgical circuit includes an active electrode and a dispersive (return) electrode, while there are 2 active electrodes in bipolar mode. In monoterminal mode, there is an active electrode, but there is no dispersive electrode connected to the patient’s body and instead the earth acts as the return electrode. Biterminal mode uses a dispersive electrode connected to the patient’s body, has a higher maximum power, and can be safer than monoterminal mode in certain situations. Electrosurgical units have different technologies for controlling the output power and for providing safety. A thorough understanding of these technologies helps with a better selection of the appropriate surgical generator and modes. ( J Am Acad Dermatol 2014;70:607.e1-12.) Key words: bipolar; biterminal; electrosurgery; high frequency; monopolar; monoterminal; power; radiofrequency.

INTRODUCTION The term electrosurgery (radiofrequency surgery) refers to the passage of high-frequency electrical current through the tissue in order to achieve a specific surgical effect. Previous generations of electrosurgical generators used a spark gap and/or a vacuum tube to make the desired high-frequency electrosurgical currents. However, modern units use transistors to make high-frequency currents with a variety of waveforms. The shape of an electrosurgical current waveform does not have any direct effect on the final tissue results of the current. The only variables that determine the final tissue effects of a current are the rate and depth at which heat is produced.1-3 In electrosection, the ratio of peak to average voltage of a current affects the depth of coagulation on the incision walls; with higherpeaked voltages there is deeper coagulation.2,4-6 Electrosurgical currents can be delivered to the tissue in monopolar or bipolar and monoterminal or biterminal modes, with the primary difference between these modes being their safety profiles. Different electrosurgical generators may have different current waveforms, different technologies for the control of output power, and different safety technologies. A better understanding of these technologies and their applications and an awareness of potential complications of electrosurgery

From the Center for Dermatology Research, Departments of Dermatology,a Pathology,b and Public Health Sciences,c Wake Forest School of Medicine. The Center for Dermatology Research is supported by an unrestricted educational grant from Galderma Laboratories, L.P. Dr Feldman is a consultant and speaker, has received grants, or has stock options in Abbott Labs, Amgen, Anacor Pharmaceuticals, Inc, Astellas, Caremark, Causa Research, Celgene, Centocor Ortho Biotech Inc, Coria Laboratories, Dermatology Foundation, Doak, Galderma, Gerson Lehrman Group, Hanall Pharmaceutical Co Ltd, Informa Healthcare, Kikaku, Leo Pharma Inc, Medical Quality Enhancement Corporation, Medicis

helps to improve efficacy and safety of surgical procedures.

BIPOLAR VERSUS MONOPOLAR ELECTROSURGERY Key points d

d

In monopolar electrosurgery, there is an active electrode and a dispersive electrode, while in bipolar mode there are 2 active electrodes In bipolar mode, electrical current passes only through the tissue grasped between the tips of the bipolar forceps

In electrosurgery, the prefixes mono- and bipolar refer to the number of active electrodes. In monopolar electrosurgery, an active electrode carries current to the tissue (Fig 1). Current then spreads through the body to be collected and returned to the electrosurgery unit by a largesurface dispersive electrode. The dispersive electrode is also known as the return, neutral, passive, or patient plate electrode. Two types of dispersive electrodes are in common use today: conductive and capacitive. With the conductive type, a metallic foil or conductive polymer is attached to the patient’s skin. With the capacitive type, the conductive foil has an insulating

Pharmaceutical Corporation, Medscape, Merck & Co, Inc, Merz Pharmaceuticals, Novan, Novartis Pharmaceuticals Corporation, Peplin Inc, Pfizer Inc, Pharmaderm, Photomedex, Reader’s Digest, Sanofi-Aventis, SkinMedica, Inc, Stiefel/GSK, Suncare Research, Taro, US Department of Justice, and Xlibris. Drs Taheri, Mansoori, Sandoval, Williford, and Pearce have no conflicts of interest to declare. Reprint requests: Arash Taheri, MD, Department of Dermatology, Wake Forest School of Medicine, 4618 Country Club Rd, Winston-Salem, NC 27104. E-mail: [email protected]. 0190-9622/$36.00

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Fig 1. A monopolar, biterminal electrosurgery circuit. High-frequency electric current flows from the active electrode, through the patient’s body, and then to the return (dispersive) electrode. Heat generation is practically limited to the area of high current density, meaning adjacent to the active electrode. The arrows indicate the direction of the electricity in 1 phase of current. In the next phase, the current will flow in the opposite direction. (Reprinted with permission from Taheri A, Mansoori P, Sandoval LF, Feldman SR, Pearce D, Williford PM. Electrosurgery. Part I: Basics and principles. J Am Acad Dermatol 2014;70:591-604.)

Unlike monopolar electrosurgery, where the patient’s body forms a major part of the electrical circuit, in bipolar electrosurgery, only the tissue grasped between the tips of a bipolar forceps is included in the electrical circuit (Fig 2). These bipolar forceps act as 2 active electrodes.8,9 The bipolar mode is used primarily for the coagulation of pedunculated benign tumors or hemostasis of blood vessels. It potentially causes less damage to surrounding tissue and reduces risk of distant site burn to the patient compared to monopolar electrosurgery.8,9

BITERMINAL VERSUS MONOTERMINAL ELECTROSURGERY Key points d

d

d

Fig 2. A bipolar electrosurgery circuit. The electric current flows from 1 forceps tine through the tissue placed between the tips to the other forceps tine, and then back to the electrosurgical generator. The bipolar mode is safer than the monopolar mode with regard to the potential extent of injury and possibility of distant site burns.

layer on the outside that prevents direct contact with the patient’s skin. The insulated electrode and the patient’s skin form a capacitor that passes a capacitive current.7 Both types of dispersive electrodes have specific advantages and disadvantages. Electrode failures and subsequent patient injury can be attributed mostly to improper application, electrode dislodgment, and electrode defects rather than to electrode design.7 Monopolar electrosurgery should be performed with caution on an extremity such as a finger or penis because there is limited cross-sectional area for the return current to spread across. Theoretically, this may result in a higher current density and some heating throughout the volume of the extremity, leading to unintentional thermal damage if a high power is used for a relatively long activation time.

d

d

In monoterminal electrosurgery, no dispersive electrode is connected to the patient’s body and the earth acts as the return electrode. Monoterminal mode can only be performed using earth-referenced electrosurgical units, which have a return electrode connected to earth In isolated electrosurgical units, the return electrode is not connected to earth. Therefore, there will be no current flow and no thermal effect unless the dispersive electrode is attached to the patient’s body (biterminal mode) Biterminal mode has a higher maximum power and theoretically may be safer than monoterminal mode in certain settings Coagulation, fulguration, and electrosection can be performed in either biterminal or monoterminal mode; however, biterminal mode is the preferred mode for electrosection Inadequate contact of the dispersive electrode with the patient’s body may result in a burn at this site. A contact quality monitoring system can disable the power if the dispersive electrode is not in adequate contact with patient’s skin

The prefixes mono- and bi- terminal refer to the number of electrodes that are in contact with the patient’s body (Figs 1 and 3). Bipolar electrosurgery is always biterminal; monopolar electrosurgery could be monoterminal or biterminal. In so-called ‘‘earth-referenced’’ electrosurgical units, the return electrode is connected to earth (usually through the power supply cable), and therefore the earth and all conductive objects around the patient’s body can act as a capacitive dispersive electrode (Fig 3). Electrosurgery can be performed using these units regardless of whether a dispersive electrode is attached to the patient. Performing

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Fig 3. Monoterminal electrosurgery using an earthreferenced unit. The return electrode is connected to the earth. Therefore, the earth and all conductive objects around the patient’s body can act as a capacitive return electrode. The current passes through the earth and comes back to the generator.

monopolar electrosurgery without using a dispersive electrode is called monoterminal or single-electrode electrosurgery (Fig 3). Because the maximum output power is far lower when the dispersive electrode is not used, only relatively low-powered electrosurgery can be performed in monoterminal mode.5 Monoterminal mode reduces the power but not the peak voltage; therefore, a pure cut cannot be performed using this mode. Biterminal is the preferred mode for electrosection.4-6 During monoterminal electrosurgery with an earth-referenced unit, if an electrically conductive object—such as a metal table, electrocardiogram electrode, or surgical staff—comes into contact with the patient’s body, some current may select the object as a low-resistance return pathway to the ground. If the contact area is small, current concentration at this point may result in a burn at this site (Table I). For this reason, monoterminal mode can be safely used only on conscious patients who would be aware of such complications, and only on carefully insulated tables with no exposed metallic parts near the patient’s body. Using a good return electrode ensures that current returns to the path of least resistance and does not take any alternative path through operators or environmental objects. Therefore, use of the return electrode, although not technically necessary for operation of an earth-referenced unit, will enhance the power and potentially safety of the electrosurgical apparatus. Earth referenced electrosurgery units are not commonly used in operating rooms today. However, many surgeons still prefer them for outpatient, office-based minor surgical procedures, avoiding the additional time and cost associated with the use of a dispersive electrode. The type of electrosurgical unit commonly used in operating rooms today is known as floating or

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isolated. In contrast to the earth-referenced units, the dispersive electrode is isolated from earth. This means that the current can return to the electrosurgery unit only via the dispersive electrode. An isolated generator will not work unless the dispersive electrode is attached to the patient—a safety feature of these units.3 During activation, if the patient’s body comes in contact with an environmental object, very low or no current passes through the object and the risk of a burn is low. The surgeon can touch an active electrode and not be burned so long as he or she does not touch the patient or dispersive electrode with the other hand. Unfortunately, the isolation of these units from earth or environmental objects is never complete, because a high-frequency current is not always completely confined by insulation. Current leakage does occur by forming a capacitor between electrode cables and the floor of operating room or conductive environmental objects.3,4 There is still therefore a potential for distant site burns. Although a good dispersive electrode reduces the risk of distant site burns, inadequate contact of the dispersive electrode with the patient’s body may result in a smaller contact area and current concentration at this point that may lead to a burn at this site.1,3,18,19 Most modern electrosurgery units include a contact quality monitor for the dispersive electrode that measures the quality of the contact between the patient’s skin and dispersive electrode and also between the electrode and the generator (Fig 4). If the dispersive electrode becomes dislodged or there is a high resistance between the dispersive electrode and the patient’s skin, the unit will sound an alarm and the power will be disabled. Theoretically, this technology reduces the risk of burns at the dispersive electrode, but there is no clinical evidence supporting this idea.20 There also have not been any clinical trials comparing the rate of side effects between an earth-referenced monoterminal device and a biterminal isolated device with or without a contact quality monitor. The best location for placement of the dispersive electrode is a muscular site well supplied with blood vessels and adjacent to the surgical field. If there is any metal in patient’s body, the dispersive pad should be placed between the metal and the surgical site to prevent current from passing selectively through the metal.

CONTROLLING THE OUTPUT POWER OF ELECTROSURGICAL DEVICES Key points d

In constant voltage electrosurgical generators, voltage is the output variable that can

Burns

Mechanism

Concentration of current on the skin

Ignition of flammable gases

Modern electrosurgical currents do not stimulate cardiac tissues; however, if an internal defect were present in the generator, the low-frequency input power theoretically may be connected to the electrodes and pass through the patient body Malfunction of electronic implanted devices

Transmission of infection

In electrosurgery, heat is generated in tissue; therefore, the active electrode may remain cold during electrosurgery and transfer bacteria and viruses to the surgical wound Microorganisms, such as human papillomavirus, may become aerosolized in blood microdroplets or in electrosurgical smoke

When working with earth-referenced generators, using a dispersive electrode in good contact with the skin decreases the chance of burning The patient should not touch environmental conductive objects An earth-referenced generator should not be used in unconscious patients, patients with neuropathy who cannot sense the pain of a possible burn, and patients attached to an electrocardiogram or blood gas monitor When working with isolated generators, using a dispersive electrode in good contact with the skin and a contact quality monitoring system decreases the chance of burning at the return electrode site The return electrode should be placed over an area of the skin with good perfusion (over a muscular area) and enough sensation, not on bony prominences, distal extremities, scar tissues, or foreign bodies An active electrode cable should not be put near the patient The surgeon should not touch the active electrode, even when gloved Using nonflammable cleanser before surgery and avoiding flammable anesthetic gases are mandatory. When using alcohol-based cleansers, the surface should be completely dry for a few minutes before beginning electrosurgery. Rich oxygen environments may facilitate the ignition of flammable materials and should be avoided If possible, the return electrode should be placed between the heart and the surgical site to prevent current from passing selectively through the heart. This theoretical complication is less likely to occur with fully isolated units than with earth-referenced units An alternative method, such as scalpel surgery, electrocautery, or CO2 laser may be used. For electrosurgery, a return electrode should be placed between the device and the surgical site. Using bipolar mode and low power reduces the risk. If the patient is not dependent on the device, turning it off may reduce the chance of malfunction; the patient should be closely monitored Disposable or sterilized electrodes should be used

An alternative method such as cryotherapy may be used; a smoke evacuator, surgical mask, and eye protection can be used; slow coagulation does not induce explosion or smoke formation and is safer than fulguration or cutting

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Cardiac arrhythmia

Prevention and management

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Table I. Common complications and pitfalls associated with electrosurgery6,10-17

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Power in Watts

80

Large electrodes ← → Small electrodes

70

C

60 50 40

B

30 20

A

10 0 0

200

400

600

800

1000 1200 1400 1600 1800 2000

Resistance in Ohms

Fig 4. An electrosurgery unit with a contact quality monitor for the dispersive electrode. Contact quality is monitored by splitting the return electrode into 2 parts and measuring the resistance between the parts. If both parts are in good contact with the skin, the resistance between them will be low. If one or both parts are not in good contact with skin, the resistance will be high and the monitoring system will disable the power.

d

d

be adjusted on the display panel. The power deployed in tissue is not only dependent on this voltage but also on the resistance in the electrodeetissue contact area When working with a constant voltage, the quality of surgical effect is dependent on the type of tissue and its electrical resistance, but not on the size of the electrode used In some devices, an automatic power adjustment mode provides a constant output power regardless of tissue resistance. In this mode, the quality of surgical effect is dependent on the size of the electrode used, but not on the type of tissue or its electrical resistance, as long as the power remains constant

There are 2 types of electrosurgical generators regarding the output-power control system: constant voltage and automatic power adjustment (Fig 5).3,7 Most conventional electrosurgical generators use a constant voltage output system. In these generators, voltage is the output variable that can be adjusted on the display panel. The dial setting for control of voltage in these units is usually calibrated using numbers from 1 to 10. These generators deliver less power to the tissue with higher resistance compared to the tissue with lower resistance, using the same voltage setting (W = V2/R; where W = power, V = voltage, and R = resistance).3,4,7 Therefore, working

Fig 5. Power-resistance curves of an electrosurgical unit. A, Constant-voltage mode with a nominal load of 200 ohms, when the maximum power is set at 30 watts. B, The same mode when the maximum power is set at 70 watts. Increasing the size of the electrode leads to lower resistance and higher power. Therefore, current density at the electrodeetissue interface and quality of tissue effect (except for the depth of effect) will not change significantly with changing the size of electrode. However, a very large electrodeetissue contact area with \200 ohms resistance leads to a reduction in power and possibly an inability to achieve the desired surgical effect. C, Automatic power adjustment mode provides a constant output power between 200 and 1400 ohms. These units do not automatically adjust the power according to the electrode size.

on a dried hyperkeratotic epidermis may need a higher voltage setting than when working on the dermis to achieve the same effect. More recent constant voltage generators are supplemented with an arbitrary dial setting with a display calibrated in watts. The indicated power refers to the maximum power that can be delivered to the nominal resistance in the circuit (Fig 5). A resistance in the circuit that is higher or lower than the nominal resistance leads to an output power lower than maximum power. Therefore, the power actually delivered to the tissue is usually lower than this maximum. This type of display has the advantage of allowing a limited degree of comparison to be made between different units or modes. In electrosurgical generators with an automatic power adjustment system (tissue-responsive or tissue-adaptive generators), power is the output variable that can be adjusted on the display panel, with the dial setting calibrated in watts. These generators can provide a constant power in a wide range of resistances in the circuit (Fig 5, C ). They can provide the same surgical effect in different tissues with different electrical resistances at the same

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Note: Some electrosurgical units show an index named ‘‘crest factor’’ that is the ratio of peak voltage to average voltage of their continuous cutting current. Generators with lower crest factors are able to provide cleaner cuts with less collateral damage and less hemostasis in pure cutting mode. Most available electrosurgical units in the market have an output frequency of 0.3-5 MHz. There is no strong evidence showing any relation between frequency of electrosurgical currents and their effects on tissue. A few studies are available but can be criticized because of poor study methods.21

Safest profile Low power (usually around 70-200 watts), isolated units, with constantvoltage output mode

Minor dermatologic procedures on conscious patients

Most dermatologic procedures

More cost-effective and convenient to use

Expensive; some devices may lack an ability to provide a very low output power for very superficial minor destructions Lower safety profile; may have fewer available modes and flexibilities; some have only 1 interrupted current for coagulation and fulguration May be less convenient to use than earth-referenced units More available modes and flexibilities

High power (usually 200-400 watts), isolated generators, with constantvoltage or automatic power adjustment mode Low power (usually around 40-100 watts), earth-referenced units, with constant-voltage output mode Major surgeries and endoscopic (urologic) procedures in operating rooms

Commonly used devices Setting and indications

Table II. The choice of the electrosurgical unit based on the surgical setting

Advantages

Disadvantages

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power setting.3,7 However, if the electrodeetissue contact area is increased, power is not increased in proportion with the contact area. Therefore, the power setting should be increased manually to provide enough power to warm up a larger area and create the same surgical effect. Both technologies have specific advantages and disadvantages. The choice of one technology may depend on the surgeon’s preferences and the price of the unit (Table II).

CLINICAL CONSIDERATIONS IN ELECTROSURGERY Key points d

d

d

d

d

Electrosection results in the histologic distortion of surgical margins. For specimens requiring histopathologic analysis, scalpel surgery is preferred Hemostasis of a bleeding vessel can be performed by clamping the vessel and passing a relatively low-power continuous current (cutting mode) through the clamp. Current flow should be stopped when a popping sound is heard or spark is seen For hemostasis of an oozing surface, contact coagulation is the preferred mode. Fulguration usually is less efficient because it results in fragmentation of the coagulated layer Penetrating proximally insulated electrosurgical electrodes can be used for coagulation of subcutaneous targets, such as tumors or varicose veins Fractional radiofrequency skin rejuvenation devices which use penetrating electrodes are used for fractional heating of the dermis and collagen remolding while preserving the epidermis

Electrosection versus scalpel surgery Electrosection results in more collateral tissue damage compared to scalpel surgery, creating some histologic distortion of surgical margins. Thermal damage causes carbonization at the excision margin, vessel thrombosis, and collagen denaturation.22,23 Cellular changes may include vacuolar degeneration, shrunken and shriveled cell outlines with condensation and elongation of the nuclei, or fusion of cells into a structureless homogeneous mass with a hyalinized appearance.24 In frozen sections, normal structures may mimic tumors, such as basal cell carcinaoma.25 It also may make it impossible to distinguish squamous and melanocytic neoplasms. For specimens requiring histopathologic analysis—especially during the excision of tumors

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that require the margins to be assessed—scalpel surgery is preferred. Electrosection in pure cutting mode may cause less thermal damage artifact than using a blend cut.26,27 Electrosection often serves as an alternative to scalpel surgery; however, there is conflicting evidence in studies comparing these modalities with respect to outcomes, such as postoperative pain, infection, wound healing, and scar formation. While many studies support better outcomes using scalpel surgery, there is also literature favoring electrosection.26,28-30 A general concept is to avoid electrosection for cutting skin when a primary closure is planned. Electrosection versus CO2 laser surgery Like electrosection, CO2 laser can provide coagulation of the incision walls and hemostasis. Both techniques, especially electrosection, are operatordependent and cannot be standardized. Therefore, it is not easy to compare these methods in clinical settings. There is conflicting evidence in studies comparing the depth of collateral injury and final results of surgery using these modalities. While some studies show more collateral coagulation using a CO2 laser, others report the opposite results.27,29-36 Compared to CO2 lasers, electrosurgery generally is less expensive, does not require eye protection, and is more accessible. Electrocoagulation for achieving hemostasis Hemostasis of a bleeding vessel can be performed by clamping the vessel and passing a monopolar current through the clamp or using a bipolar electrode.37 Care should be taken to prevent spark formation and tissue fragmentation or charring at the end of coagulation. A relatively low-power continuous current (cutting mode) is the preferred current in order to prevent large spark formation. A popping sound may be heard or a spark may be seen at the time of desiccation, and at this time current flow should be stopped.5 For hemostasis of an oozing surface, contact coagulation is the preferred mode. Fulguration usually is less efficient because it results in fragmentation of the coagulated layer. Wiping of the coagulated area should be avoided if possible, because it can cause disruption of the coagulated layer and result in more bleeding. One should remember that coagulation of a surface for achieving hemostasis results in damage to the surface that may adversely affect postoperative and aesthetic outcomes.4-6,38 To optimize hemostasis, the operative field should be dry, because blood diffuses the current flowing from the electrode. A dry operative field is also essential for cutting and coagulation. Proximally insulated bipolar electrodes can help with more

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effective hemostasis in wet environments. Electrocautery, as opposed to high-frequency electrosurgery, may function in wet environments, although not as effectively as in dry fields. Electrosurgery for hair removal Hair removal can be performed using a needle electrode that enters the hair follicle and applies a direct electrical current (galvanic current). The resulting chemical reaction (electrolysis) around the electrode destroys the hair follicle. The process is relatively slow and time-consuming. Using an electrosurgical alternating current, the follicle can be destroyed using thermal damage (thermolysis). This process is faster than electrolysis; however, there is a greater risk of damage to the dermis around the hair follicle and scar formation.39-41 Electrosurgery in the treatment of malignant skin tumors Curettage and electrodesiccation has been used successfully in the treatment of many different benign and malignant skin tumors.42-44 For treatment of cancers, this procedure is usually repeated $ 2 times in an attempt to remove any small tumor extensions. The procedure may be less morbid, faster, and more cost-effective to perform than excision and repair in certain cases with certain tumors. A great advantage of curettage over surgical excision arises from the ability of a semisharp curette to differentiate and remove friable abnormal tissue from the normal surrounding tissue with minimal sacrifice of normal skin.44 However, this method is operator-dependent and cannot be easily standardized because the depth of coagulation achieved is dependent on many factors, such as size of the electrode and power used.45 Treatment of basal cell carcinoma with curettage and electrodesiccation results in cure rates ranging from 88% to 99% depending on the location and size of tumor and the surgical method used. Studies that reported the highest cure rates destroyed a wider peripheral margin around the initial curettage, ranging from 2 to 8 mm.6,46-50 Electrosurgery in the treatment of benign superficial skin tumors Upon a mild thermal coagulation, the epidermis and papillary dermis turns to a soft material (liquefaction) that can be easily wiped off of the surface of the skin surface. However, the reticular dermis does not respond in the same way; instead, it maintains its durability and remains solid and cannot be wiped off after coagulation or desiccation.51 This phenomenon

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helps the surgeon to distinguish the papillary from the reticular dermis. For the treatment of superficial epidermal overgrowths, such as seborrheic keratoses or plane warts, a very superficial coagulation using a fine-tip electrode or electrofulguration with a low output power can be performed. The area may be wiped off after coagulation to see if any epidermal tissue remains in place that requires a second pass of superficial coagulation. To achieve a very superficial coagulation using a fine-tip electrode, a very low power should be chosen. Spark formation that occurs at the time of desiccation indicates the occurrence of deeper injury and should be avoided by reducing voltage, power, and/or contact time. Penetrating insulated electrosurgical electrode for the destruction of subcutaneous targets Electrocoagulation of a variety of tumors in internal organs has been performed using penetrating, proximally insulated electrodes.52,53 Recently, this approach has been used for the treatment of the deeper component of infantile hemangioma of the skin.54 Endovascular thermal ablation of varicose veins using a long, flexible electrosurgical electrode with insulation on the proximal parts is used as a less invasive alternative to traditional surgery.55,56 Compared to surgery, this approach provides the same efficacy with less postoperative morbidity and a lower rate of adverse events.57 Proximally insulated needles can also be used for treating telangiectasias.58 Penetrating insulated electrodes have also been used for ablation or denervation of corrugator supercilii muscle for treatment of hyperdynamic vertical glabellar furrows.59-61 Electrosurgical currents in aesthetic medicine and skin rejuvenation High-frequency electrical currents (radiofrequency technology) has been used for the treatment of cellulite, acne scar, inflammatory acne, skin resurfacing, and nonablative tightening of skin to improve laxity and reduce wrinkles.62-70 Most of the devices marketed for these purposes use $ 1 electrodes to deliver the current to the skin surface (epidermis). However, the manner in which some of these devices work is not completely understood.71 For skin tightening, the most acceptable explanation is that the heating of dermal tissue by high-frequency (radiofrequency) currents results in remodeling of collagen fibers and subsequent neocollagenesis.66,72 Most of these methods have struggled to gain attention in the

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scientific literature, and there is a paucity of wellconducted randomized trials supporting their efficacy.72 There is evidence, however, of the success of fractional radiofrequency systems with penetrating electrodes in dermal heating and collagen remodeling. In contrast with the devices that deliver the current to the epidermis, these devices deploy energy directly to the dermis.73-77 Multielectrode pins of these devices provide heating of the areas that are directly targeted by the electrodes, leaving intact or only slightly affected zones between the targeted areas.73-77 The preserved tissue serves as a pool of cells that promote rapid wound healing. Depending on the technology used, when an electrode of a fractional radiofrequency device enters the skin, the maximum heating effect can be around the tip of the electrode in dermis because highfrequency electrical currents have a tendency to propagate toward the center of the bulk of tissue.78 This phenomenon can preserve the epidermis during dermal heating and reduce the risk of postprocedural side effects, including postinflammatory dyspigmentation. By insulating the proximal end of the penetrating electrode, the epidermis will escape injury more efficiently during heating of the dermis.79 In contrast to radiofrequency currents, laser-based fractional resurfacing may produce greater tissue injury on the surface of the skin (epidermis) than in the reticular dermis.80,81 However, to our knowledge there is no clinical trial comparing these modalities. Electrosurgery and implantable electronic devices Electrosurgery has been reported to cause destruction, reprogramming, depleted battery, and inhibition or activation of implantable electronic devices. Skipped beats, asystole, bradycardia, ventricular fibrillation, and unspecified tachyarrhythmia have been reported with use of electrosurgery in patients with cardiac implantable electronic devices.82-84 The incidence of interference is higher when using the monopolar rather than bipolar mode, using a higher power, working near the implanted device, or having the pacemaker between the active and dispersive electrode.82 Recent improvements in electrical shielding and filtering systems have made implanted electronic devices more resistant to outside electrical interference.84 Heat electrocautery is a safe alternative to electrosurgery in patients with implanted electronic devices. Practical differences between different electrosurgical units Electrosurgical units have different output power, output frequency, and can provide different modes.

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The choice of the unit depends on the surgical setting and the desired applications (Table II).

CONCLUSIONS Bipolar electrosurgery is primarily used for the coagulation and hemostasis of small- to mediumsized blood vessels or in certain situations, such as surgery on a finger or a patient with an implantable electronic device. The bipolar mode theoretically can be safer than the monopolar mode with regard to the potential extent of injury and possibility of distant site burns. With regard to safety, the monoterminal mode may be limited in electrosurgery, especially when using a high power on an unconscious patient or a patient with neuropathy who cannot sense the pain of possible burns. However, if an earth-referenced device cannot provide a very low power for a fine coagulation, the monoterminal mode can be used to reduce output power. The correct use of a return electrode increases the power and safety of the electrosurgical device. Although the application of electricity in surgery dates back 100 years, progress in technology still leads to the introduction of new methods and indications. More recent applications of electrosurgery include the treatment of varicose veins, treatment of benign subcutaneous tumors, and fractional skin rejuvenation. A thorough understanding of the technology and its possible complications can promote effective application of electrosurgical techniques and improved outcomes. REFERENCES 1. Brill AI. Electrosurgery: principles and practice to reduce risk and maximize efficacy. Obstet Gynecol Clin North Am 2011; 38:687-702. 2. Tokar JL, Barth BA, Banerjee S, Chauhan SS, Gottlieb KT, Konda V, et al. Electrosurgical generators. Gastrointest Endosc 2013;78:197-208. 3. The Association of Surgeons in Training web site. Principles of electrosurgery. Available from: http://www.asit.org/assets/ documents/Prinicpals_in_electrosurgery.pdf. Accessed February 2, 2013. 4. Bussiere RL. Principles of electrosurgery. Edmonds (WA): Tektran Inc; 1997. 5. Pollack SV. Electrosurgery of the skin. 1st ed. New York: Churchill Livingstone; 1990. 6. Soon SL, Washington CV. Electrosurgery, electrocoagulation, electrofulguration, electrodesiccation, electrosection, electrocautery. In: Robinson JK, Hanke CW, Siegel DM, Fratila A, editors. Surgery of the skin: procedural dermatology. 2nd ed. New York: Elsevier; 2010. pp. 225-38. 7. Eggleston JL, von Maltzahn WW. Electrosurgical devices. In: Bronzino JD, editor. The biomedical engineering handbook. 2nd ed. Boca Raton (FL): CRC Press; 2000. 8. Brill AI. Bipolar electrosurgery: convention and innovation. Clin Obstet Gynecol 2008;51:153-8.

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9. Rioux JE. Bipolar electrosurgery: a short history. J Minim Invasive Gynecol 2007;14:538-41. 10. Netherton BL, Stecker MM, Patterson T. Mechanisms of electrode induced injury. Part 3: practical concepts and avoidance. Am J Electroneurodiagnostic Technol 2007;47: 257-63. 11. Kushiyama S, Inoue K, Morioka T, Isa T. New safety system for prevention of inadvertent skin burn in the use of electrosurgical unit. Am J Surg 1978;135:868. 12. Rabhan NB. Electrosurgery electrode safety. J Am Acad Dermatol 1987;17(2 Pt 1):312. 13. Sebben JE. The hazards of electrosurgery. J Am Acad Dermatol 1987;16:869-72. 14. Alkatout I, Schollmeyer T, Hawaldar NA, Sharma N, Mettler L. Principles and safety measures of electrosurgery in laparoscopy. JSLS 2012;16:130-9. 15. Mowatt G, Cook JA, Fraser C, McKerrow WS, Burr JM. Systematic review of the safety of electrosurgery for tonsillectomy. Clin Otolaryngol 2006;31:95-102. 16. Safety in laparoscopic electrosurgery. OR Manager 1999;15: 30. 17. Odell RC. Electrosurgery: principles and safety issues. Clin Obstet Gynecol 1995;38:610-21. 18. ECRI. Higher currents, greater risks: preventing patient burns at the return-electrode site during high-current electrosurgical procedures. Health Devices 2005;34:273-9. 19. Edrich J, Cookson CC. Electrosurgical dispersive electrodes heat cutaneous and subcutaneous skin layers. Med Instrum 1987;21:81-6. 20. Van Way CW, Hinrichs CS. Electrosurgery 201: basic electrical principles. Curr Surg 2000;57:261-4. 21. Maness WL, Roeber FW, Clark RE, Cataldo E, Riis D, Haddad AW. Histologic evaluation of electrosurgery with varying frequency and waveform. J Prosthet Dent 1978; 40:304-8. 22. Mausberg R, Visser H, Aschoff T, Donath K, Kruger W. Histology of laser- and high-frequency-electrosurgical incisions in the palate of pigs. J Craniomaxillofac Surg 1993; 21:130-2. 23. Matsumoto K, Suzuki H, Usami Y, Hattori M, Komoro T. Histological evaluation of artifacts in tongue tissue produced by the CO2 laser and the electrotome. Photomed Laser Surg 2008;26:573-7. 24. Elliott JA Jr. Electrosurgery. Its use in dermatology, with a review of its development and technologic aspects. Arch Dermatol 1966;94:340-50. 25. Revercomb CH, Stewart CE, Bux RC. Artifact from an electrosurgical ground pad. Am J Forensic Med Pathol 1997;18:293-4. 26. Kashkouli MB, Kaghazkanai R, Mirzaie AZ, Hashemi M, Parvaresh MM, Sasanii L. Clinicopathologic comparison of radiofrequency versus scalpel incision for upper blepharoplasty. Ophthal Plast Reconstr Surg 2008;24:450-3. 27. Courey MS, Fomin D, Smith T, Huang S, Sanders D, Reinisch L. Histologic and physiologic effects of electrocautery, CO2 laser, and radiofrequency injury in the porcine soft palate. Laryngoscope 1999;109:1316-9. 28. Loh SA, Carlson GA, Chang EI, Huang E, Palanker D, Gurtner GC. Comparative healing of surgical incisions created by the PEAK PlasmaBlade, conventional electrosurgery, and a scalpel. Plast Reconstr Surg 2009;124: 1849-59. 29. Silverman EB, Read RW, Boyle CR, Cooper R, Miller WW, McLaughlin RM. Histologic comparison of canine skin biopsies collected using monopolar electrosurgery, CO2 laser,

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Electrosurgery: part II. Technology, applications, and safety of electrosurgical devices.

Electrosurgical currents can be delivered to tissue in monopolar or bipolar and monoterminal or biterminal modes, with the primary difference between ...
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