Electrosurgery and cardiac devices

Preventing and managing complications in dermatologic surgery: Procedural and postsurgical concerns

The second article in this continuing medical education series reviews the evidence regarding the intraoperative and postoperative risks for patients and health care workers. We share the most up-to-date recommendations for risk management and postoperative complication management to ensure optimal surgical efficacy and patient safety.

Pacemakers, Deep Brain Stimulators, Cochlear Implants, and Nerve Stimulators: A Review of Common Devices Encountered in the Dermatologic Surgery Patient

BACKGROUND

In dermatologic and procedural surgery settings, there are commonly encountered devices in patients. Safe surgical planning requires familiarity with these devices.

OBJECTIVE

To review the current implanted devices in patients and recommendations for surgical planning around these devices.

METHODS AND MATERIALS

A comprehensive review using PubMed and published device recommendations was performed, searching for those most relevant to dermatologic surgery.

RESULTS

Devices such as pacemakers and implantable cardiac defibrillators, deep brain stimulators, cochlear implants, and various nerve stimulators are potential devices that may be encountered in patients and specific recommendations exist for each of these devices.

CONCLUSION

Dermatologic surgeons' knowledge of implanted devices in patients is paramout to safe surgical procedures.

Endovascular Electrical Stimulation - A Novel Hemorrhage Control Technique

OBJECTIVE

In this study we present a novel approach for inducing vasoconstriction by pulsed electrical treatment delivered via endovascular electrodes, which can be used in cases where external access to the vessel is limited.

METHODS

Using computer simulations, we optimized various geometries of endovascular electrodes to maximize the induced electric field on the arterial wall. Using the optimal configuration parameters, we investigated endovascular induced vasoconstriction in both the carotid and femoral sheep arteries.

RESULTS

Endovascular electrodes induced robust vasoconstriction in the carotid artery of sheep, showing gradual recovery following treatment. Moreover, the obtained vasoconstriction was accompanied by a sevenfold decrease in blood loss for 100% constriction, compared with no treatment (6ml vs 42ml, p<0.001). The femoral artery was less amenable to the electrical treatment, which we hypothesize results from the reduced density of the sympathetic system's innervation of the adventitia of the sheep femoral artery, as was validated by immunohistochemical analysis. Finally, treatment safety was validated through arterial histological studies, in which no adverse effect was observed, and through computer modeling, which depicted a negligible temperature increase.

SIGNIFICANCE

These results are an important step toward developing a novel approach for inducing reversible and controlled vasoconstriction in arteries that are remote from access.

Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction - a Finite Element Simulation Study

Hemorrhagic shock accounts for 30-40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach.

Anesthetic Implications for Patients With Implantable Cardioverter Defibrillators

Implantable cardioverter defibrillators have become one of the preferred methods for treating many life- threatening ventricular arrhythmias. Many tens of thou sands of these devices have been implanted and this, together with the ease of worldwide travel, has made it more likely that anesthesiologists everywhere may come into contact with these patients either for elective or emergency surgery. These patients present unique anesthetic challenges because of the combination of the device and severe underlying cardiac disease. This article presents an overview of the implantable defibril lator as it affects the anesthesiologist, including device function, device assessment, electromagnetic interfer ence, and perioperative management.

Dermatologic surgery on the chest wall in patients with a cardiac surgery history: a review of material that may be encountered intraoperatively, including potential complications and suggestions for proceeding safely

Background

Thoracic surgical procedures and the use of cardiac devices such as pacemakers are becoming increasingly prevalent in the population. As such, dermatologists may have a greater likelihood of encountering previously implanted or abandoned surgical material in the course of dermatologic surgery on the chest wall. A basic understanding of the wire types and the tunneling paths utilized in such procedures is important in accurately anticipating the presence of these wires to effectively manage any chance encounters.

Objective

We present a review on temporary epicardial pacing wires, temporary transvenous pacing wires, pacemaker leads, and surgical steel sutures in the context of dermatologic surgery.

Methods

A literature review was performed on frequently used wire material in patients with a history of cardiac surgery as well as related dermatologic complications from these materials.

Results & Conclusion

Dermatologic surgeons should particularly be aware that temporary epicardial pacing wires and pacemaker leads are not uncommonly abandoned in the chest wall of many patients. All patients with a cardiac surgery history should be questioned about possible retained wires. If wire material is encountered intraoperatively, immediately stop the procedure and do not attempt further manipulation of the wire until suggested steps are taken to ascertain the wire type.

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 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.

Electrosurgery in patients with implantable electronic cardiac devices (pacemakers and defibrillators)

The electrosurgical unit is a very useful tool widely used in dermatology to treat benign and malignant skin lesions and to achieve hemostasis during surgery. However, precautions are required when this technique is used in patients with implantable electronic cardiac devices (IECD), such as pacemakers and defibrillators, because electromagnetic interference produced by the tool may cause such devices to malfunction. Before using electrosurgery in patients with IECDs, it is essential to ascertain the type of implanted device and the patient's level of dependence on it. The location of the skin lesion to be treated with respect to the device should also be assessed. Bipolar pacemakers are more resistant to interference. Appropriate monitoring and the use of bipolar forceps are recommended.

Pacemakers and Implantable Cardiac Defibrillators in Dermatologic Surgery

BACKGROUND

Electrosurgery used during dermatologic surgical procedures can cause malfunction of pacemakers and implantable cardiac defibrillators (ICDs), producing problems with rhythm detection, proper function, or alteration of the device. Well-documented safety data on electrosurgery in patients with cardiac devices are limited. At Mayo Clinic in Rochester, Minnesota, the Pacemaker Clinic manages all patients with pacemakers and ICDs undergoing dermatologic surgery. The preoperative and postoperative evaluations provide a unique opportunity to evaluate the safety of dermatologic surgery with electrosurgery in such patients.

OBJECTIVES

The objective was to review the evaluation and management, by an experienced cardiology team, of patients with cardiac devices undergoing dermatologic surgery and to characterize perioperative complications.

METHODS

A retrospective chart review of all patients identified with pacemakers or ICDs undergoing Mohs micrographic or dermatologic excisional surgery with electrosurgery at Mayo Clinic 2001 through 2004 were identified. Data were abstracted to identify any possible complications.

RESULTS

The 173 patients with pacemakers and 13 with ICDs undergoing dermatologic surgery had no documented complications from electrosurgery.

CONCLUSION

The lack of complications associated with pacemakers and ICDs with electrosurgery is reassuring. The authors support published recommendations about techniques and precautions to optimize safety during electrosurgery in patients with cardiac devices. The care of patients with ICDs in particular requires special consideration.

Electrosurgery in Patients With Pacemakers/Implanted Cardioverter Defibrillators

Despite improved protective mechanisms, pacemakers and implanted cardioverter defibrillators are subject to interference from various sources. An effective means of hemostasis, electrocautery generates electromagnetic interference and may be problematic in this patient population. Reported complication rates are low, but the consequences can be serious. Recommendations regarding the management of patients with implanted cardiac devices become increasingly significant both as the number of patients with devices increases and the number of out-of-hospital/minor surgery procedures performed increases. This article provides surgeons and anesthetists with practical recommendations for use of electrocautery in patients with pacemakers or implantable cardiac defibrillators.

Excision of Malignant Melanoma Overlying a Pacemaker

BACKGROUND

With the increasing number of patients with implantable cardiac devices, dermatologic surgeons must be increasingly familiar with the types of devices and potential interference by surgical procedures.

OBSERVATIONS

We report the excision of a 1 cm malignant melanoma in situ occurring on the skin directly overlying the patient's pacemaker.

CONCLUSIONS

Successful excision of malignant lesions in the setting of implantable cardiac devices requires an understanding of pacemaker implantation anatomy following well-established guidelines for electrosurgery in the setting of implantable cardiac devices and careful coordination with cardiac and anesthesia specialists.

Mohs Micrographic Surgery in a Patient with a Deep Brain Stimulator: A Review of the Literature on Implantable Electrical Devices

BACKGROUND

Implantable electrical devices are becoming increasingly common in the patient population presenting for Mohs micrographic surgery. In addition to understanding the potential intraoperative complications with implantable cardioverter-defibrillators and pacemakers, the Mohs surgeon needs to be aware of the relatively new treatment of movement disorders using implanted deep brain stimulators.

OBJECTIVE

We present only the second reported case of Mohs surgery in a patient with a deep brain stimulator. In an attempt to help minimize adverse events during a procedure, we review the more commonly encountered electrical devices as well as the newer deep brain stimulators. We provide guidelines for the avoidance of electromagnetic interference during an electrosurgical procedure.

METHODS

This 76-year-old patient with Parkinson's disease and an implanted deep brain stimulator underwent Mohs surgery for excision of a squamous cell carcinoma on the ear. In an attempt to minimize electromagnetic interference with his implanted device, hemostasis was obtained with the aid of a battery-operated heat-generating handheld electrocautery device.

RESULTS

The patient tolerated the procedure well without complications or reports of discomfort.

CONCLUSION

Patients with implanted electrical devices are subject to electromagnetic interference during an electrosurgical procedure. Care must be taken in this expanding patient population during a Mohs surgical procedure.

Finite element analysis of hepatic radiofrequency ablation probes using temperature-dependent electrical conductivity

BACKGROUND

Few finite element models (FEM) have been developed to describe the electric field, specific absorption rate (SAR), and the temperature distribution surrounding hepatic radiofrequency ablation probes. To date, a coupled finite element model that accounts for the temperature-dependent electrical conductivity changes has not been developed for ablation type devices. While it is widely acknowledged that accounting for temperature dependent phenomena may affect the outcome of these models, the effect has not been assessed.

METHODS

The results of four finite element models are compared: constant electrical conductivity without tissue perfusion, temperature-dependent conductivity without tissue perfusion, constant electrical conductivity with tissue perfusion, and temperature-dependent conductivity with tissue perfusion.

RESULTS

The data demonstrate that significant errors are generated when constant electrical conductivity is assumed in coupled electrical-heat transfer problems that operate at high temperatures. These errors appear to be closely related to the temperature at which the ablation device operates and not to the amount of power applied by the device or the state of tissue perfusion.

CONCLUSION

Accounting for temperature-dependent phenomena may be critically important in the safe operation of radiofrequency ablation device that operate near 100 degrees C.

Effects of steel scalpel, ultrasonic scalpel, CO2 laser, and monopolar and bipolar electrosurgery on wound healing in guinea pig oral mucosa

OBJECTIVE

The study's objective was to compare instrument performance and tissue healing when steel scalpel, ultrasonic scalpel, monopolar or bipolar electrosurgical instruments, or CO2 laser was used in an animal oral surgery model.

STUDY DESIGN

Prospective, blinded, randomized.

METHODS

Adult guinea pigs (N = 70) were randomly assigned to 5 groups (14 animals per group) for excision of 2-cm, full-thickness oral mucosa using steel scalpel, ultrasonic scalpel, monopolar or bipolar electrosurgical instruments, or CO2 laser. Postoperative pain was measured indirectly using weekly body weight changes. Animals from each group were killed on days 0, 7, 14, 21, and 28. Specimens were harvested for blinded histopathological study and tensile strength measurement. Instrument performance (hemostasis, tissue coagulation, tissue sticking) and wound healing (tissue re-epithelialization, degree of inflammation) were primary outcomes. Statistical analysis was performed using analysis of variance.

RESULTS

The ultrasonic scalpel was the best tool in controlling hemostasis, tissue coagulation, and tissue sticking. Significantly higher body weight gain ( P<.05) was noted at day 7 for monopolar and CO2 laser groups. Greatest tensile strength was seen in the steel scalpel and ultrasonic scalpel groups at the end of 28 days. Tissue re-epithelialization was fastest for the steel scalpel and ultrasonic scalpel groups (complete by day 7). Complete re-epithelialization of wounds of all treatment groups occurred by day 28. All groups had acute inflammation. Complete resolution of inflammation by day 14 took place in the steel scalpel and ultrasonic scalpel groups only.

CONCLUSION

Use of the ultrasonic scalpel produced faster re-epithelialization and greater tensile strength than laser or electrosurgical instruments, with results comparable to those seen with the steel scalpel.

Crowns and other extra-coronal restorations: impression materials and technique

Well-fitting indirect restorations can only be made if there are accurate models of the oral tissues available, made from high quality impressions. Waiting for an impression to set may be more stressful for the dentist than the patient. Should the impression need to be repeated there is the embarrassment of having to explain this to the patient, the cost implications of material and time wasted and the aggravation of running late for the next appointment. Yet, if a 'Nelsonian' eye is turned to a defective impression we can only expect a substandard restoration in return.

Electrosurgery in Otolaryngology???Head and Neck Surgery: Principles, Advances, and Complications

OBJECTIVES/HYPOTHESIS

Electrosurgical instruments are routinely used in many applications by otolaryngologist-head and neck surgeons; and a complete description of their historical development, physics of operation, histological effects, and technological advancements is necessary for our specialty to take full advantage of this instrumentation. Because of the electrical current, heat production, and common use associated with these instruments, compounded by the complex environments in which they are used, potential complications must be considered and are likely underreported in the literature. This thesis describes the important aspects of electrosurgery along with a study of complications so otolaryngologists can use these instruments to their fullest potential while limiting complications.

STUDY DESIGN

National survey of electrosurgical complications.

METHODS

A survey addressing potential complications of electrosurgery was developed based on a review of the electrosurgical and complications literature. The electrosurgical complications were organized in the following categories: 1) unanticipated direct burns as a result of the active electrode contacting some tissue unintentionally; 2) unintentional burns as a result of capacitive coupling where radiofrequency (RF) current passes through a metallic instrument (such as forceps) and burns tissue in contact with that metallic instrument; 3) fires occurring as a result of electrosurgical instruments; 4) electromagnetic interference with a pacemaker, defibrillator, or cardiac monitoring device; and 5) other complications not included in the previous categories. The survey was mailed to the 620 members of the Society of University of Otolaryngologists.

RESULTS

Of the 620 surveys mailed, 35 were returned by the post office for lack of a forwarding address and 296 were returned completed for a response rate of 49.7%. The respondents performed a total of 99,664 cases in the previous year. During that year, 324 complications related to electrosurgical instruments were reported. These included 219 unanticipated direct burns, 48 burns as a result current flow through a metallic retractor or instrument (capacitative coupling), 13 grounding pad burns, 11 fires, 32 cases of electromagnetic interference, and 1 hair loss at an incision site as a result of a cutting electrosurgical instrument. Information regarding the circumstances surrounding these complications and outcome are presented.

CONCLUSIONS

Electrosurgery has proliferated since its original application by William T. Bovie and Harvey Cushing in the 1920s. Because surgeons use this technology frequently, a thorough understanding of these instruments and their potential complications is critical to their safe and successful use. Electrosurgical units operate on basic fundamental principles of physics and involve the passage of electrical current through tissue to create the desired tissue effect. With knowledge of the history, physics, techniques, histological effects, and safety issues of electrosurgery, the field will continue to proliferate and electrosurgery will continue to assist surgeons in alleviating human suffering.

Electrosurgery, pacemakers and ICDs: a survey of precautions and complications experienced by cutaneous surgeons

BACKGROUND

Minimal information is available in the literature regarding the precautions implemented or complications experienced by cutaneous surgeons when electrosurgery is used in patients with pacemakers or implantable cardioverter-defibrillators (ICDs). The literature pertinent to dermatologists is primarily based on experiences of other surgical specialties and a generally recommended thorough perioperative evaluation.

OBJECTIVE

To determine what precautions are currently taken by cutaneous surgeons in patients with pacemakers or ICDs, and what types of complications have occurred due to electrosurgery in a dermatologic setting.

METHODS

In the winter of 2000, a survey was mailed to 419 U.S.-based members of the American College of Mohs Micrographic Surgery and Cutaneous Oncology (ACMMSCO).

RESULTS

A total of 166 (40%) surveys were returned. Routine precautions included utilizing short bursts of less than 5 seconds (71%), use of minimal power (61%), and avoiding use around the pacemaker or ICD (57%). The types of interference reported were skipped beats (eight patients), reprogramming of a pacemaker (six patients), firing of an ICD (four patients), asystole (three patients), bradycardia (two patients), depleted battery life of a pacemaker (one patient), and an unspecified tachyarrhythmia (one patient). Overall there was a low rate of complications (0.8 cases/100 years of surgical practice), with no reported significant morbidity or mortality. Bipolar forceps were utilized by 19% of respondents and were not associated with any incidences of interference.

CONCLUSIONS

Significant interference to pacemakers or ICDs rarely results from office-based electrosurgery. No clear community practice standards regarding precautions was evident from this survey. The use of bipolar forceps or true electrocautery are the better options when electrosurgey is required. These two modalities may necessitate fewer perioperative precautions than generally recommended, without compromising patient safety.

Cutaneous electrosurgery in a patient with a deep brain stimulator

BACKGROUND

Deep brain stimulators are implantable devices with electrical activity used to treat certain movement disorders such as essential tremor and Parkinson's disease. Similar to implantable cardiac devices, use of electrosurgery on patients with these devices may produce adverse effects.

CASE REPORT

We describe the effects of electrosurgery on a patient with essential tremor and an implantable deep brain stimulator who required Mohs micrographic surgery to excise a basal cell carcinoma. The patient experienced immediate lancinating "electrical shock" using electrosurgery in the monopolar mode. The patient experienced no discomfort when a bipolar electrosurgical device was used or when his deep brain stimulator was "turned off." Appropriate positioning of the dispersive plate also reduced adverse effects.

CONCLUSION

Dermatologic surgeons should be aware of patients with devices implanted in the CNS with electrical activity and proceed with caution when using electrosurgery. Different approaches can be utilized to help reduce adverse effects.