Monopolar Electrosurgery Research Articles

Monopolar Electrosurgical Thermal Management for Minimizing Tissue Damage

In this study, a novel thermal management system (TMS) is developed for the minimization of thermal spread created by a monopolar electrosurgical device, the most commonly used surgical instrument. The phenomenon of resistive heating of tissue is modeled using the finite-element method (FEM) to analyze the electrical potential and temperature distributions in biological tissue subjected to heat generation during monopolar electrosurgery. Ex vivo experiments are used to validate the FEM by comparing the model predicted and experimentally measured temperatures. The predicted FEM maximum temperature 1.0 m adjacent to the electrode is within 1% of the experimentally measured maximum temperature using a standard monopolar pencil electrode. A TMS consisting of adjacent cooling channels produces coagulation volumes 80% that of standard monopolar procedures while maintaining comparable temperatures in the targeted tissue below the electrode. In vivo temperatures using a device incorporating a TMS at distances of 2 and 3 m adjacent to the electrode edge are maintained below temperatures known to damage tissue.

Monopolar Electrosurgery through Single-Port Laparoscopy: A Potential Hidden Hazard for Bowel Burns

Background Surveys indicate that up to 90% of general surgeons and gynecologists use monopolar radiofrequency during laparoscopy and 18% have experienced visceral burns. Monopolar electrosurgery compared with other energy sources is associated with unique characteristics and inherent risks and complications caused by inadvertent direct or capacitive coupling or insulation failure of instruments. These dangers become particularly important with the reemergence of single-port laparoscopy, which requires close proximity and crossing of multiple intraabdominal instruments outside the surgeon’s field of view. Study Objectives To determine the effects of monopolar electrosurgery on various tissues/organs during simulated single-port laparoscopic surgery in vitro and in vivo. Design Simulation in a dry laboratory with fresh sheep liver, pig bowel and bowel in an anesthetized dog (Canadian Classification II-3). Setting University-affiliated teaching hospital and animal facilities. Measurements and Main Results We used Valleylab Force 2 and FX electrosurgical generators at clinically used power outputs of 40 to 60 watts, and both high- and low-voltage (coagulation and cut) waveforms and commercially-available single-port devices. The effect on tissue was recorded by pictures and video camera and graded visually and histologically with hematoxylin and eosin stains. During activation of any standard monopolar laparoscopic instrument (scissors, coagulating electrode, etc), capacitive coupled currents resulting in visible tissue burn (blanching) caused by other adjacent cold instrument (graspers, etc) including metallic suction-irrigation cannulas and the laparoscope itself were noted. Histopathologic study confirmed transmural thermal damage extending to the mucosa of small bowel, even in the presence of mild serosa blanching. With prolonged activation of the electrosurgical generator, the capacitive coupled corona discharge burned the insulation and caused rapid insulation breakdown of the electrode instrument resulting in direct coupling (sparking, arcing) to adjacent cold instruments and more severe burning to the contacted tissue/organ. Conclusions During single-port laparoscopy and use of monopolar radiofrequency, the proximity and crossing of multiple instruments generate capacitive or direct coupled currents, which may cause visceral burns.

Residual heat of laparoscopic energy devices: how long must the surgeon wait to touch additional tissue?

Energy devices are essential laparoscopic tools. Residual heat is defined as the increased instrument temperature after energy activation is completed. This study aimed to determine the length of time a surgeon needs to wait before touching other tissue using four common laparoscopic energy sources. Thermal imaging quantified instrument and tissue temperature ex vivo using monopolar coagulation, argon beam coagulation, ultrasonic dissection, and bipolar tissue fusion devices. To simulate realistic operative usage, each instrument was activated for 5 s four consecutive times with 5 s pauses between fires. Thermal conductivity to bovine liver tissue was measured 2.5, 5, 10, and 20 s after final activation. The maximum increase in instrument tip temperature was 172 ± 63°C for the ultrasonic dissection, 81 ± 18°C for the monopolar coagulation, 46 ± 19°C for the bipolar tissue fusion, and 1 ± 1°C for the argon beam coagulation (P < 0.05 for all comparisons). Touching the instrument tip to tissue at four intervals after the final activation (2.5, 5, 10, and 20 s) found that ultrasonic energy raised the tissue temperature higher (maximum change, 58°C) than the other three energy devices at all four time points (P < 0.05). Ultrasonic energy instruments have greater residual heat than monopolar electrosurgery, bipolar tissue fusion, and argon beam. The ultrasonic energy instrument tips heated tissue more than 20°C from baseline even 20 s after activation; whereas all the other energy sources raised the tissue temperature less than 20°C by 5 s. These practical findings may alter a surgeon's usage of these common energy devices.

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.

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.

Electrosurgical Tenoscopic Desmotomy of the Accessory Ligament of the Superficial Digital Flexor Muscle (Proximal Check Ligament) in Horses

To report a tenoscopic technique using monopolar electrosurgery to transect the accessory ligament of superficial digital flexor muscle (AL-SDFM) and outcome in 33 horses. Case series. Horses (n=33). Medical files and surgery video recordings of horses that had AL-SDFM desmotomy performed by tenoscopy with monopolar electrosurgical electrodes were reviewed. Of 33 horses, 24 were Standardbred racehorses with surgery performed bilaterally for superficial digital flexor tendonitis and 9 horses had flexural deformity. Severe (n=6) and mild (6) intrathecal hemorrhage was the most common intraoperative complication. Large intrathecal vessels including the nutrient artery were successfully electrocoagulated and AL-SDFM transection was completed. Clear/serosanguinous drainage from skin incisions was observed for 4.3±3.3 days (mean, SD). Protracted wound drainage for >4 days occurred in 10 horses, principally in the group treated for flexural deformities (P=.01). Sixty-four AL-SDFM were transected under tenoscopic observation using monopolar electrodes. Electrocoagulation of large intrathecal vessels, including the nutrient artery, was possible in all cases and allowed completion of desmotomy. Postoperative wound care was similar to routine tenoscopy in most (70%) horses. Aseptic protracted wound drainage was observed in 30% of horses (principally those with flexural deformity), and led to a prolonged hospitalization.

Effect of glossectomy technique on histopathologic assessment in a rat model

The purpose of this study was to compare the tissue effects of 3 surgical methods of glossectomy with respect to histopathologic assessment by a pathologist. The anterior tongue of 30 Sprague-Dawley rats was excised using either a steel scalpel, monopolar electrosurgery, or ultrasonic scalpel (3 groups of 10). Specimens were examined by a pathologist blinded to the surgical procedure, using a previously described grading system for margin artifact assessment. Minimal tissue disruption at the surgical margin was produced by the steel scalpel, in contrast to monopolar electrosurgery and ultrasonic scalpel, which both produced varying levels of tissue distortion. Margin fragmentation was significantly greater with monopolar electrosurgery when compared to an ultrasonic scalpel. Ultrasonic scalpel creates less tissue distortion at the surgical margin than monopolar electrosurgery. Further study is required to determine the clinical relevance of these findings.

Single Port Laparoscopy and Monopolar Electrosurgery May Result in Visceral Burns

Single Port Laparoscopy and Monopolar Electrosurgery May Result in Visceral Burns

Surgeon-controlled Factors That Reduce Monopolar Electrosurgery Capacitive Coupling During Laparoscopy

To determine the factors that can be modified by the surgeon to reduce monopolar electrosurgery capacitive coupling during laparoscopy. Specific aims were to determine the capacitive coupling energy using different generator power settings, mode settings (cut vs. coagulation), and surgical techniques (desiccation vs. fulguration vs. open air activation). An oscilloscope determined the cumulative energy (Joules) of capacitive coupling occurring using laparoscopic monopolar electrosurgery ex vivo. Higher power settings increased capacitive coupling energy (Joules): 25 Watts (1.1±0.7) versus 50 Watts (2.4±0.5; P<0.05). Coagulation mode created greater capacitive coupling energy (2.2±1.0) in comparison with cut mode (1.1±0.5; P<0.05). Open air activation (3.3±0.6) and fulguration (3.3±1.0) had higher capacitive coupling energy in comparison with desiccation (0.6±0.2; P<0.05). Surgeons can minimize capacitive coupling energy during laparoscopy by lowering the power setting, using cut mode (instead of coagulation), and using the surgical technique of desiccation (instead of open air activation or fulguration).

Monopolar electrosurgery through single port laparoscopy may result in visceral burns

OBJECTIVE: Monopolar electrosurgery compared with other energy sources is associated with unique inherent risks and complications due to inadvertent direct and/or capacitive coupling or insulation failure of instruments. These dangers become particularly important with the re-emergence of single-port laparoscopy which requires close proximity and crossing of multiple intra-abdominal instruments. Our objective is to determine the effects of monopolar electrosurgery on various tissues/organs during simulated single-port laparoscopic surgery in vitro and in vivo.

Anti-Sticking Properties of PVD CrWN&lt;sub&gt;x&lt;/sub&gt;, CrO&lt;sub&gt;x&lt;/sub&gt; and ZrO&lt;sub&gt;x&lt;/sub&gt; Coatings on Medical Electrode Application

The side effect of electrosurgery includes tissue charring, smoke generation and the adhesion of tissue to electrodes. These effects prolong surgery and interfere with effective coagulation. In this paper, CrWNx, CrOx and ZrOx coating were prepared by an unbalanced magnetron sputtering. The microstructure of films was characterized using XRD, XPS, TEM and AFM. The hydrophobicity and surface energy of coatings were calculated by contact angle measurement and Wu harmonic mean approach. Anti-sticking in vitro test was performed by monopolar electrosurgery using pork liver tissue. The hardness of CrWNx , ZrOx and CrOx coatings were 44 GPa, 26.3 GPa and 20.7 GPa, respectively. The CrOx coating had the lowest surface energy 33.5 mN/m and the highest contact angle of water as high as 103°. The high surface O-H bonds density of CrOx coating and N-H bonds density of CrWNx coating could explain about their lower polar component of surface energy. All the three PVD coatings remarkably reduced the quantity of tissue adhesion on the electrode from about 2 times (ZrOx and CrWNx coatings) to 4.88 times (CrOx coating) than uncoated SUS304 electrode.

Comparison of the thermal and histopathological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model

To compare the thermal and histopathological effects of two commercially available bipolar systems and conventional monopolar transurethral resection of the prostate (TURP) in a canine model. Bipolar TURP is an alternative to monopolar electrosurgery for treating benign prostatic hyperplasia and has several potential clinical advantages, including the ability to use normal saline irrigation, enhanced haemostasis and less collateral thermal damage. In all, 12 adult male beagles were studied. After midline laparotomy and exposure of the bladder and prostate, two fibre-optic thermosensors were placed to record tissue temperatures; one sensor was placed into the substance of the prostate 2 cm from the urethra and the second in the prostatic-rectal groove on the capsular surface of the prostate to measure temperatures in the region of the neurovascular bundles. Through a midline cystotomy, antegrade TURP was performed using two different bipolar systems (Gyrus PlasmaKinetic and Vista, both from Gyrus-ACMI Corporation, Maple Grove, MN, USA) or a monopolar device (Force(TM) 2, Valleylab, Boulder, CO, USA). TURP was performed in each lateral lobe using 24 F resection loops. The dogs were humanely killed acutely and the prostates excised for histopathological assessment. When comparing intraprostatic temperature data, the mean (sem) temperature changes recorded for the monopolar group were significantly higher than in either the Gyrus or Vista bipolar groups, at 24.2 (3.9) degrees C vs 8.1 (1.5) degrees C and 6.8 (1.8) degrees C, respectively (P < 0.001). No measurable temperature elevations were recorded near the neurovascular bundles with any of the electrosurgery devices. The depth of thermal damage was greatest in the monopolar group at 0.59 (0.27) mm compared with the Gyrus and Vista groups at 0.07 (0.08) mm and 0.15 (0.02) mm, respectively (P < 0.001). Bipolar TURP generated significantly less heat and histopathological evidence of thermal damage compared with monopolar TURP in the present canine model.

Use of the PlasmaJet® System in Patients Undergoing Abdominal Lipectomy Following Massive Weight Loss: A Randomized Controlled Trial

Abdominoplasty has become a popular body-contouring procedure among patients with deformity resulting from massive weight loss. We present the results of a randomized controlled trial comparing the PlasmaJet® System (PJS) and conventional monopolar electrocautery for the treatment of the dissection surfaces in patients undergoing corrective abdominoplasty following massive weight loss. Sixty consecutive patients were randomized to undergo abdominoplasty either with conventional monopolar electrosurgery or PJS. The two groups were comparable regarding demographics, associated conditions, smoking habits, type and number of previous bariatric procedures, amount of lost weight, as well as previous abdominal scars. The primary end point was the rate of procedure-related postoperative complications and secondary end points were the time of wound drainage, total accumulated fluid drainage volume, the duration of hospital stay, and patients' satisfaction. There were significantly less postoperative complications in the PJS group, namely wound infection (p < 0.05). There was no difference in the total amount of fluid output from the abdominal drains but the latter were retrieved 1day before on average in the PJS group, and patients in the PJS group were discharged on average 1day before patients in the control group. Overall, better cosmetic results were obtained in the PJS group (p < 0.05). Patients undergoing abdominoplasty with the PJS showed a lower rate of postoperative complications (p < 0.05), were discharged on average 1day before patients in the control group and had better cosmetic results (p < 0.01).

A Comparison of Histopathologic Margin Assessment after Steel Scalpel, Monopolar Electrosurgery, and Ultrasonic Scalpel Glossectomy in a Rat Model

At the conclusion of this presentation, the participants should be able to describe the tissue effects of steel scalpel, monopolar electrosurgery, and ultrasonic scalpel glossectomy with respect to histopathologic margin assessment in a rat model. Histopathologic margin assessment is important in guiding treatment and determining prognosis for squamous cell cancer of the oral tongue. Energy based devices for glossectomy produce varying degrees of tissue distortion and artifact that can influence margin assessment. The purpose of this study is to compare the tissue effects of three surgical methods of glossectomy with respect to margin assessment by a pathologist. Blinded histopathologic study of three surgical techniques for glossectomy using a rat model. The anterior tongue of thirty Sprague-Dawley rats was excised using either steel scalpel, monopolar electrosurgery, or ultrasonic scalpel (three groups of ten). Specimens were fixed in formalin and serially sectioned, and hematoxylin and eosin stains were examined by a pathologist blinded to the surgical procedure. Comparison between surgical techniques with respect to effect on the tissue margin was carried out using a previously described grading system for margin assessment. Minimal tissue disruption at the surgical margin was produced by the steel scalpel, in contrast to monopolar electrosurgery and harmonic scalpel, which both produced varying levels of tissue distortion. Margin fragmentation, cautery artifact, and artifact depth was greater with monopolar electrosurgery when compared to harmonic scalpel. Energy based devices cause tissue distortion which may in theory effect the ability to accurately assess surgical margins for tumor involvement on histopathology. In our rat model of glossectomy, the harmonic scalpel created less tissue distortion at the surgical margin than monopolar electrosurgery. Further study is required to determine the clinical relevance of these findings.

Laparoscopic Cholecystectomy With Harmonic Scalpel

Laparoscopic cholecystectomy is the "gold standard" in the treatment of symptomatic gallbladder lithiasis. Nevertheless, some pitfalls are associated with the use of the monopolar hook, such as the risk of thermal injuries and biliary complications. By contrast, the ultrasonically activated scalpel, ie, Harmonic (Ethicon Endo Surgery INC - Johnson & Johnson Medical SPA, Somerville, NJ) in laparoscopic cholecystectomies has been increasingly used for dissection of the gallbladder and for division of vessels and the cystic duct, because it reduces the risk of thermal injuries. During a 2-year period, in a personal series of 95 consecutive patients, the Harmonic scalpel was used as the sole instrument for both division and dissection of the cystic artery and duct. The average length of inpatient stay, procedure duration, and complications were compared with the data of a homogenous control group of patients who were treated using monopolar electrosurgery and clips. Neither major complications nor bile duct injuries were detected in either group, and no statistically significant difference was found between the 2 in terms of the incidence of postoperative complications. However, the mean operative time was significantly shorter in patients treated with the Harmonic scalpel. The Harmonic scalpel is not only a safe and effective instrument but also a reliable substitute for clips because it provides complete hemobiliary stasis. Even if the study revealed no differences with regard to postoperative complications, the Harmonic scalpel represents a viable alternative because of the shorter operation time and cost savings that are inherent in a procedure using it as a single instrument.

Monopolar and Bipolar Hysteroscopic Electrosurgery: New Insights into the Differences between Surgery in Insulating and Conducting Liquid Media

Monopolar and Bipolar Hysteroscopic Electrosurgery: New Insights into the Differences between Surgery in Insulating and Conducting Liquid Media

Can Harmonic Focus Curved Shear Effectively Seal the Pancreatic Ducts and Prevent Pancreatic Leak? Feasibility Evaluation and Testing in Ex Vivo and In Vivo Porcine Models

The purpose of this study was to evaluate the ability of Harmonic energy technology to transect and seal the pancreatic duct compared with the standard monopolar electrosurgery transection and oversew technique in a porcine distal pancreatectomy survival model. Harmonic energy technology is as effective as standard oversew technique for preventing pancreatic leak after distal pancreatectomy. The animal protocol used for this study was approved by the Institutional Animal Care and Use Committee (IACUC) prior to the conduct of the study. Spleen-preserving distal pancreatectomy was performed in seven pigs (80-100 lb) by the same surgeon. In four animals, the pancreas was divided with the Harmonic Focus Curved Shears (test group) with no additional suturing for control of hemostasis or leak. In three animals, the pancreas was divided using monopolar electrosurgery (30 W coagulation) and the cut end of the pancreas was oversewn with a locking suture (control group). A previously worked out standard operative technique was used in all procedures. Operating end points included surgery time and blood loss. Animals were euthanized and necropsied at 7 to 8 d following surgery. Survival endpoints included clinical response to surgery, serum chemistry profiles before surgery and at necropsy, and histology of the pancreas transection site. Mean operative time for pancreatic resection was 15min in the control group and 10min in the test group. No significant blood loss was noted in either group. The median size of the resected pancreas was 4.3 cm. Three animals in the control group and three in the test group completed the study without complications. One animal in the test group failed to eat, appeared dehydrated, and was taken off study on POD#2. In this animal, there was a doubling of serum lipase at euthanasia and gross evidence of ileus, which was attributed to a pancreatic leak. Histologic examination of the residual pancreas in both groups at necropsy revealed a 2-5 mm band of necrotic tissue associated with neutrophilic infiltration in the control group, and less than a 1mm band of necrotic tissue in the test group. The Harmonic Focus Curved Shears, using Harmonic energy technology, appears to seal the pancreatic ducts and prevent pancreatic leak at 75% (3/4) efficiency in this survival model. However, the survival leak rate, 25% (1/4) was higher in the Harmonic Focus Curved Shears test group compared with the control oversewn group 0% (0/3). This feasibility study shows potential for Harmonic technology to be used to seal the pancreatic ducts, but additional testing and optimization of surgical techniques are needed.

Monopolar Electrosurgery on the Extrahepatic Bile Ducts During Laparoscopic Cholecystectomy

The purpose of this study is to investigate the occurrence of thermal injury in the extrahepatic bile ducts when monopolar electrosurgery is used to perform dieresis of the cystic duct and cystic vessels in laparoscopic cholecystectomy. Female pigs (n=40) of the Large White breed were separated into 2 groups of 20 animals. In the experimental groups, dieresis of the cystic duct and cystic vessels was performed with monopolar electrosurgery using a hook-like dissector using a power setting of 20 W, whereas in the control group this procedure was performed with a pair of Metzenbaum scissors disconnected from any kind of thermal energy source. Occurrence of distal thermal injury was evaluated on 2 occasions, on the 3rd and 28th days postoperatively. It consisted of exploratory laparotomy, cholangiography and both macroscopic and microscopic examination of the surgical specimen, which included cystic duct stump, hepatic duct and choledochus. The presence of distal thermal injury, classified as second degree, 1.2 mm in the portion near the clipping area, was observed in only one of the cystic duct stumps after microscopic examination, without statistical significance. No thermal injury was observed in the extrahepatic bile ducts. Monopolar electrosurgery produced negligible thermal injury in the extrahepatic bile ducts after laparoscopic cholecystectomy.

Principles and Practical Applications of Electrosurgery in Laparoscopy

Monopolar electrosurgery remains a popular energy choice in laparoscopic surgery. The aim of this video is to highlight theoretical electrosurgical principles as they relate to practical applications of monopolar electrosurgery. We briefly trace the history of electrosurgical development and the engineering innovations that have made monopolar energy inherently safe. The efficacy and versatility of this modality is further emphasized though a series of instructive surgical video clips.

Prospective randomized study of monopolar scissors, bipolar vessel sealer and ultrasonic shears in laparoscopic colorectal surgery

Many instruments are used for laparoscopic dissection, including monopolar electrosurgery scissors (MES), electrothermal bipolar vessel sealers (BVS) and ultrasonically coagulating shears (UCS). These three devices were compared with regard to dissection time, blood loss, safety and costs. Sixty-one consecutive patients undergoing laparoscopic left-sided colectomy were randomized to MES, BVS or UCS. The primary endpoint was dissection time. Patient and operation characteristics did not differ between the groups. Median dissection time was significantly shorter with BVS (105 min) and UCS (90 min) than with MES (137 min) (P < 0.001). With BVS and UCS, significantly fewer additional clips were required (MES 9 versus BVS 0 versus UCS 3; P < 0.001) and there was a trend towards lower blood loss (125 versus 50 versus 50 ml respectively; P = 0.223) and a reduced volume of suction fluid (425 versus 80 versus 110 ml; P = 0.058). Overall satisfaction was similar for the three instruments. Dissection with BVS and UCS was significantly cheaper than with MES, assuming a centre volume of 200 cases per year (P = 0.009). BVS and UCS shorten dissection time in laparoscopic left-sided colectomy and are cost-effective compared with MES.