Electrosurgery Unit Research Articles

Evaluating the Effects of Different Dental Devices on Implantable Cardioverter Defibrillators

IntroductionThe implantable cardioverter defibrillator (ICD) is an electronic device that emits electrical signals to the heart via lead wires and electrodes. It is used for cardiac rhythm monitoring and treatment. Because electronic dental devices have been shown to produce electromagnetic fields, we hypothesize that they may interfere with ICD function. MethodsNine dental devices (heat carrier, electronic apex locator, electric pulp tester, unipolar electrosurgery unit, electric motor, curing light, and 3 gutta-percha guns) were tested in this study for their ability to interfere with the function of 4 ICDs (2 single-chambered and 2 dual-chambered ICDs). ICD activity was monitored for 30 seconds using an ICD programmer (Medtronic 2090; Minneapolis, MN) and evaluated through an electrogram test strip printout. ResultsElectromagnetic interference was detected with the electric motor, curing light, electric pulp tester, and electrosurgery unit although no electromagnetic disturbances were detected with these devices. No electromagnetic interferences were observed for the gutta-percha guns, heat carrier, and apex locator. However, the electrosurgery unit affected the dual-chambered ICD (Consulta CRT-D, Medtronic) and delivered therapies for fibrillation when no ventricular fibrillation was present. ConclusionsOur results suggest that the electrosurgery unit produces electromagnetic disturbances with unwanted therapy delivery shock and potentially clinically significant outcomes.

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Use of electro surgery units (ESU) in surgeries is linked with electromagnetic field emission, which is assessed according to the requirements of occupational health and safety legislation. Surgeons' exposure characteristics was monitored during 11 surgeries (proctectomy, patency of artery, hepatectomy, cystectomy, tonsilectomy, laparoscopy) by real time of monopolar ESU activity recorder. Investigations of root-mean-square value of electric and magnetic field strength was also performed at various modes of ESU operations during cutting (output power, 55-150 W; frequency, 330-445 kHz) and coagulating (40-240 W, 335-770 kHz). Statistical parameters of distribution of ESU operation over any 6-min periods (according to international requirements regarding protection against adverse thermal effects of electromagnetic field) were assessed. Electric field strength, measured 10 cm from the cable supplying an active electrode was 147-675 V/m during cutting and 297-558 V/m during coagulating; magnetic field strength was less than 0.2 A/m in both modes. Monitoring of ESUs showed the following ranges of their operation during surgeries 5-66% of time over starting 3 min of surgery, 3-40% over starting 6 min, and the distribution of their use over any 6-min periods 0-12% (median) / 7-43% (maximum value). The real operation time of ESUs ing surgeries was significantly shorter than that declared by workers. The distance of at least 15 cm between cables, connecting electrodes with generator and workers meets the requirements of the Polish legislation on permissible exposure limits. The assessment of localized exposure of the hand needs a detailed analysis of the SAR ratio distribution and further studies are required.

Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body

BackgroundElectrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient’s body is unknown. Numerical electromagnetic analysis can help in understanding the issue.MethodsTo this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient’s body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed.ResultsResults revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient’s anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table.ConclusionResults of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from the electrodes. This outcome is concordant with the type of surgery-related sacral burns reported in literature. Such burns cannot be immediately detected after surgery, but appear later and can be confused with bedsores. In addition, the dosimetric analysis suggests that reducing the capacity coupling between the return electrode and the operating table can decrease or avoid this problem.

An Alternative Pathway Electrosurgical Unit Injury in a Dog

To report esophageal perforation, caused by alternative current pathway from the use of a monopolar electrosurgery unit (ESU), during routine orthopedic surgery in a dog. Clinical report. Two-year-old male Labrador retriever. Medial meniscectomy and lateral suture stabilization were performed on a healthy Labrador retriever with a ruptured cranial cruciate ligament. Monopolar electrosurgery was used during the procedure for hemostasis and tissue dissection. Anesthetic monitoring was augmented with an esophageal electrocardiogram (ECG) probe. The day after surgery, the dog appeared dehydrated. After intravenous fluid therapy, respiratory distress was noted and thoracic radiography and contrast fluoroscopy revealed an esophageal perforation. Exploratory surgery was planned to repair the defect. Cardiac arrest occurred after induction. Gross necropsy findings and histopathologic examination revealed lesions consistent with thermal necrosis of the esophagus and myocardial degeneration. An internal investigation of this medical device accident revealed that multiple factors may have contributed to the injury. An alternative current pathway from the monopolar ESU to the esophageal ECG probe resulted in a full-thickness esophageal thermal injury and cardiac failure.

An Evaluation of Potential for Alternate Return Site Burns Due to Capacitive Coupling Between Active Electrode and Ground While Using Electrosurgery Units

In Brief Before the 1970s, the circuits used in electrosurgery units (ESUs) were referenced to ground. As a result, patients who came in contact with alternate paths to ground sometimes received burns. Examples of such alternate paths include current flow through metallic operating table frames, metallic frames under the instrument tables, intravenous poles, electrocardiogram probes, and towel clips. After isolation transformers were introduced in the 1970s, the ESU circuits became floating, with no direct path to ground. This significantly reduced the incidence of burns due to electrosurgery. This article evaluates the potential for alternate return site burns when using modern ESUs. A computer simulation and a laboratory test with a real ESU were performed. It is concluded that under specific circumstances a patient can be burned after 20 seconds of continuous ESU activation. These circumstances include (1) activation of the ESU without contact between the active electrode and the patient, (2) a small alternate return site contact area of 1 cm2, and (3) the use of a high-power, 200-W cut mode. Before the 1970s, the circuits used in electrosurgery units were referenced to ground. As a result, patients who came in contact with alternate paths to ground sometimes received burns. Examples of such alternate paths include current flow through metallic operating table frames, metallic frames under the instrument tables, intravenous poles, electrocardiogram probes, and towel clips. After isolation transformers were introduced in the 1970s, the electrosurgery unit circuits became floating, with no direct path to ground. This significantly reduced the incidence of burns due to electrosurgery. This paper evaluates the potential for alternate return site burns when using modern ESU's. A computer simulation and a laboratory test with a real ESU were performed. It is concluded that under specific circumstances a patient can be burned after 20 seconds of continuous ESU activation. These circumstances include i) activation of the ESU without contact between the active electrode and the patient, ii) a small alternate return site contract area of 1cm2, and iii) the use of a high power 200 W cut mode.

Removal of a dental implant: An unusual case report

This article is a case report of removal of a dental implant using electrosurgery. A discussion will outline a possibly less invasive method to remove the dental implant. This involves the use of electrosurgery unit to cause a thermo-necrosis of the bone and therefore a weakening of the bone-implant interface. It is suggested that a controlled laboratory experiment be carried out to look at the effects of mono-polar electrosurgery on osseointergration on dental implants and the possible use of this method to allow for simple removal of poorly positioned fixtures and also fixtures with significant bone loss but no mobility.

Practice Advisory for the Prevention and Management of Operating Room Fires

Practice Advisory for the Prevention and Management of Operating Room Fires: An Updated Report by the American Society of Anesthesiologists Task Force on Operating Room Fires Jeffrey Apfelbaum;Robert Caplan;Steven Barker;Richard Connis;Charles Cowles;Jan Ehrenwerth;David Nickinovich;Donna Pritchard;David Roberson;Robert Caplan;Steven Barker;Richard Connis;Charles Cowles;Albert de Richemond;Jan Ehrenwerth;David Nickinovich;Donna Pritchard;David Roberson;Gerald Wolf; Anesthesiology

Suitability of electrosurgical analysers for routine maintenance testing of electrosurgery units – a technical note

Primary objective: To evaluate the use of electrosurgical analysers in testing power output and leakage current from an electrosurgery unit and compare this to the manufacturer recommendations for routine testing.Method: Two electrosurgical analysers were compared to reference measurements (carried out using non-inductive resistors, a current transformer and oscilloscope) over a range of tests described in IEC 60601-2-2: 1998 measuring power output and leakage currents in different conditions. The analysers used were Metron QA-ES and Fluke 454A.Outcomes: Both analysers gave similar results to the reference measurements for power output. The Metron QA-ES gave similar results to the reference measurements for leakage current testing; however the Fluke 454A gave substantially different results when used as described in the manual.Conclusions: Electrosurgical analysers can be a valuable tool in the workshop, enabling rapid, accurate testing of electrosurgery equipment without needing additional equipment and setting up times. Not all analysers can perform all the tests that may be needed and in some cases the accuracy of the results is questionable. Users must be certain of the capabilities and limitations of the analyser before making decisions based on the results.

Estrategias y trucos en la histerectomía laparoscópica compleja

Las estrategias y trucos para realizar la histerectomía laparoscópica dependen de la experiencia del cirujano y de sus ayudantes, lo cual implica una selección del paciente susceptible del procedimiento, tener a disposición el instrumental adecuado, especialmente una buena unidad electroquirúrgica, pinzas bipolares con electrodos de 3 mm de ancho, manipulador uterino que facilite el desplazamiento del útero a diferentes posiciones durante el procedimiento. Desarrollar en forma ordenada los diferentes pasos para la histerectomía laparoscópica: sección y remoción de anexos, disección del espacio vesico-uterino, separación del ligamento ancho, identificación y esqueletización de los vasos uterinos, coagulación y corte de los mismos e identificación del uréter en su trayecto intraligamentario, con lo cual se busca evitar su lesión durante la coagulación y sección de las arterias uterinas en el cérvix. Tener cuidado en la disección del espacio vesico-uterino, sobre todo en aquellas pacientes con antecedentes de cesárea previa, ya que esto aumenta la posibilidad de ruptura del órgano. Terminar por vía vaginal la histerectomía a fin de extraer el útero, previo desprendimiento de sus ligamentos de fijación. El cierre de la cúpula vaginal se puede realizar por abajo o por laparoscopia.

Impact of Dental Devices on Cochlear Implants

A cochlear implant (CI) converts mechanical sound energy into electrical signals that can be delivered to the cochlear nerve of profoundly deaf patients. The purpose of this study was to investigate whether electromagnetic interference with the CI occurs during the operation of the electric pulp tester, apex locator, electrocautery unit, electrosurgery unit, or panoramic radiograph machine. A mastoidectomy and cochleostomy were performed on a cadaver, and a CI was implanted. The dental devices were used intraorally, and the implant's circuitry was tested after each trial. A second CI was implanted in a human skull, which was then exposed to 50 panoramic radiographs, testing the implant's circuitry after each exposure. The probability of damage to the CI by any of the devices was negligible, except for the electrosurgery unit operated at level 7, which destroyed the CI's circuitry. Therefore, although the other devices seem safe, it is recommended that the electrosurgery unit not be used on a CI patient.

New Electroablation Technique Following the First-Line Stapling Method for Thoracoscopic Treatment of Primary Spontaneous Pneumothorax

A new tip for the electroablation of pneumocysts was examined clinically as a second-line method for stapled resection of pneumocysts during video-assisted thoracoscopic surgery (VATS). A trial to assess feasibility. National referral hospitals. One hundred seven patients were studied, of whom 99 patients were eligible for the study (85 men and 14 women; age range, 15 to 69 years; median age, 23 years), who had undergone VATS for primary spontaneous pneumothorax between July 1996 and June 1998. Apical pneumocysts were resected employing staplers, and residual pneumocysts, if present, were electroablated employing a new tip for the electrosurgery unit (ball shape, 8 mm in diameter, and made of stainless steel). Thirty-three patients (33%) underwent electroablation only for small (< 2 cm in diameter) pneumocysts (group S), and 11 patients (11%) underwent electroablation for large (>/= 2 cm in diameter) pneumocysts (group L). The remaining 55 patients (56%) did not undergo electroablation because there were no residual pneumocysts (group N). There were no complications during surgery. The duration of the operation was significantly shorter (about 20 min on average) for group N, but there was no significant difference in the amount of blood loss, the number of applied staples, the duration of drainage, and the duration of hospital stay. Group S achieved a 100% relapse-free rate (33 of 33 patients), group L achieved a 64% relapse-free rate (7 of 11 patients), and group N achieved an 89% relapse-free rate (49 of 55 patients) [group S vs group N, p = 0.08; group L vs group N, p = 0.001; and group S vs group L, p = 0.002]. Electroablation with the M-tip is feasible as a second-line method for the treatment of small pneumocysts following the stapling technique during VATS.

Radiofrequency transmission to monitoring devices in the operating room: a simulation study.

We evaluated radiofrequency (RF) transmission to various monitoring devices using circuits that simulated potentially hazardous conditions for patients in the operating room. Right heart ejection fraction (REF) pulmonary artery catheters, transesophageal atrial pacing stethoscopes, and temperature-sensing esophageal stethoscopes were subjected to RF transmission from an electrosurgery unit. Peak voltage and spark intensity were measured in circuits between the electrocautery dispersive pad and conductive elements of the various medical devices. All monitoring devices with an exposed conductive surface were found to have induced voltages and even spark generation. The ranking for peak voltage from least to most was as follows: disrupted esophageal stethoscope (620 volts), the transesophageal pacemaker (640 volts), and the REF pulmonary artery catheter (PAC) (680 volts). Peak voltage measurements of the REF PAC significantly decreased from 388 +/- 23 to 142 +/- 22 volts (P < 0.0001, Student's t-tests) in a fluid medium compared to air. In a fluid medium, peak voltage significantly decreased from 142 +/- 22 to 85 +/- 15 volts (P < 0.0001, Student's t-tests) when the REF PAC was connected to the cardiopulmonary monitor.

Electric and laser energy for endoscopic surgery.

Improvements in surgery have focused on refinements in the ability to dissect and limit blood loss. The electrosurgery unit (ESU) and laser (light amplification by stimulated emission of radiation) have been widely used in recent endoscopic surgery. ESU is a form of surgery in which high-frequency (100 kHz-5 MHz) electric currents are used to incise, destroy, and remove tissue and to seal blood vessels in order to maintain hemostasis. The use of lasers in surgery has added a new dimension to operative technique through increased precision, improved hemostasis, and less tissue manipulation. This paper aims to explain the basic principles and applications of electrosurgery and lasers.

Initial experience with a physiologic morcellating resectoscope

A new physiologic morcellating resectoscope allows operative hysteroscopy to be performed with a physiologic distention medium, thus reducing the risk of dilutional hyponatremia and cerebral edema secondary to excessive absorption of nonphysiologic fluid. To study this new technology, we gathered in vitro data with the SL resectoscope with dual-function electrode (FemRx, Sunnyvale, CA). Coupled to a standard monopolar electrosurgery unit and operating in normal saline or Ringer's lactate solution, extirpated uteri showed equivalent depth of tissue necrosis with this new physilogic morcellating resectoscope as with a conventional monopolar resectoscope used in an electrically nonconductive fluid.

Clinical experience with the OPERAStarSL using saline irrigation fluid for OPERA

Objective: To present clinical results using a new hysteroscopic resectoscope, the OPERAStar SL with PEARL technology, which cuts and coagulates uterine tissue in a physiologic, conductive fluid environment in order to perform OPERA, Out-Patient Endometrial Resection/Ablation. Use of physiologic normal saline in resectoscopy has not previously been feasible. Use of normal saline prevents complications such as hyponatremia and cerebral edema due to excessive absorption of traditional nonphysiologic fluids. Methods: Patients suffering from abnormal uterine bleeding with or without submucosal fibroids who were scheduled for surgical intervention underwent OPERA for treatment of their condition. The OPERAStar SL resectoscope with PEARL technology was used with a 0.9% saline distention medium. The PEARL technology insulates the active electrode so that a noninsulating fluid, such as 0.9% saline or lactated ringers, can be used while maintaining the ability to cut and coagulate tissue using a standard monopolar electrosurgery unit. Operative data recorded include uterine size, presence and size of fibroids, pretreatment with endometrial thinning agents, operative time, cutting/coagulating power levels, estimated blood loss, and calculated fluid deficit. Additional data include the ability to cut and coagulate tissue as compared to standard resectoscopes used in the physician’s clinical practice. Results: A total of 22 patients underwent operative hysteroscopy with the described resectoscope. Average age of all patients was 45 years (range 30–70), and average weight was 158 pounds (range 106–258). Eighteen (82%) patients underwent OPERA while the remaining 4 (18%) patients underwent fibroid resections. The average uterine size was 7 weeks (range 4–14). Average operative time was 26 minutes, and all procedures were successfully completed without complications. Fluid deficit averaged 480 mL (range 0.0–1.54 L) as reported by the Flo-Stat Fluid Management System. A Likert scale was used to rate the device’s ability to cut and coagulate tissue with results indicating the OPERAStar SL accomplishes the same clinical results to standard resectoscopic devices used in the physician’s clinical practice. Conclusion: Complete uterine tissue resection and ablation can now be accomplished in a saline environment. The unique PEARL technology with the OPERAStar SL resectoscope is effective in cutting and coagulating uterine tissue. Operating in a saline environment eliminates the most prevalent potential complication of operative hysteroscopy when using nonphysiologic irrigation solutions, dilutional hyponatremia, and secondary cerebral edema.

A comparison of mucosal incisions made by scalpel, CO 2 laser, electrocautery, and constant-voltage electrocautery

This study compares the histologic effects of scalpel, CO 2 laser, electrosurgery, and constant-voltage electrosurgery incisions on the mucosal tissue of swine. Tissue studies comparing the CO 2 laser with the scalpel and electrosurgery have been done. However, a gross and histologic comparison of the effects of all three techniques on oral mucosal tissue has not been reported. A swine model of both tongue and buccal mucosa was used to compare the scalpel, CO 2 laser, electrosurgery unit, and constant-voltage electrosurgery unit in an effort to assess their value in oral surgery. Tissue samples of tongue and buccal mucosal incisions and excisions were histologically examined at 0, 3, 7, 14, 28, and 42 days after surgery to evaluate tissue damage and wound healing properties induced by the four instruments. The instruments were also evaluated for performance and ease of use. On subjective evaluation of ease of use, constant-voltage electrosurgery scored highest ( p < 0.05) on a scale of 0 to 4, followed by the CO 2 laser. Speed of incisions and excisions, measured in seconds, was fastest with the scalpel ( p < 0.001) and electrosurgery unit ( p < 0.05). The amount of bleeding, as evaluated on a scale of 0 to 4, was least for electrosurgery ( p < 0.001) and CO 2 laser ( p < 0.001). Histologic damage, as expected, was least with a scalpel. The extent of epithelial damage lateral to the wound edge and the extent of collagen denaturation were the lowest with the scalpel ( p < 0.001), followed by constant-voltage electrosurgery. The wounds created by all four instruments displayed intact epithelium by 4 weeks, and granulation tissue peaked at 4 weeks with all methods except constant-voltage electrosurgery, where granulation tissue was still prevalent at week 6. Constant-voltage electrosurgery and the CO 2 laser provided the best combination of ease of use, hemostasis, and lack of tissue injury among the instruments compared. Incisions and excisions made with constant-voltage electrosurgery required less time than those made with the laser, but constant-voltage electrosurgery wounds also had significantly more granulation tissue in later weeks of the study, suggesting that wound healing may be delayed. (Otolaryngol Head Neck Surg 1997;116:379-85.)

Seized Electrosurgery Units Lack PMA

Seized Electrosurgery Units Lack PMA

Electrosurgery Units May Have Faulty Wiring Harness

Electrosurgery Units May Have Faulty Wiring Harness

Reprogrammation d'un stimulateur cardiaque induite par le bistouri électrique

A case is reported of reprogramming of a ventricular unipolar permanent pacemaker induced by electrocautery during biliary surgery. After skin incision and use of the unipolar electrosurgery unit, the CPI model 505 multiprogrammable pulse generator previously set at 70 b · min −1 abruptly fired at 120 b · min −1. Application of a magnet over the pacemaker reduced the heart rate to 100 b · min −1. After surgery, the pulse generator was successfully reprogrammed to a rate of 65 b · min −1. Based on the analysis of this case and of previous reports, it is suggested, so as to avoid such complications, that the unipolar electrocautery be avoided when the surgical field is near the pulse generator or lead; that the bipolar electrocautery be preferred; that a magnet and non-invasive programmer be available during and after surgery; and that a postoperative assessment of the pulse generator be carried out.

A method to measure operating variables in electrosurgery

Variables affecting tissue response to electrosurgical wounding have been identified and discussed. An electronic measuring device was designed and built to record actual power generated at the active electrode during surgical use of an electrosurgery instrument. In addition, this electronic device measures the amount of time the active electrode is in contact with tissue. Coupled with an electrosurgery unit producing a documented waveform and an electrosurgery electrode having a controlled-depth gauge, variables affecting tissue response to electrosurgery wounding may be measured.