Unrecognized hazards of surgical electrodes passed through metal suction-irrigation devices

Surgical electrodes, passed through metal suction-irrigation devices, pose significant risks for unrecognized visceral burns through capacitively coupled current using monopolar electrosurgery. Plastic cannulas (and reducers) should be avoided with the metal suction-irrigation electrode; an all-metal trocar cannula confers limited safety. With surgeon education and advances in engineering, the potential for unrecognized visceral injury with capacitive coupling can be eliminated.     

Port site electrosurgical (diathermy) burns during surgical laparoscopy

Background: Direct and capacitive coupling of diathermy current have been reported as causes of occult injury during surgical laparoscopy. Methods: In order to determine the incidence of electrosurgical injury adjacent to metal and plastic cannulas, skin biopsies at 19 port sites used for monopolar electrosurgery were analyzed for coagulative necrosis. Prior to surgery the cannulas were randomized to either metal or plastic. Results: Coagulative necrosis was observed at nine electrosurgery port sites compared to only one control (χ²= 4.872; df= 1; 0.05 > p > 0.02). Plastic cannulas afforded no greater protection from skin burns than metal cannulas. Conclusions: Burns may be the result of direct or capacitive coupling to metal cannulas or capacitive coupling to the skin edge across plastic cannulas. The potential exists for burns to other tissues also in close proximity to a cannula used for electrosurgery. Received: 12 August 1996/Accepted 26 November 1996     

Complications and recommended practices for electrosurgery in laparoscopy

BACKGROUND: Electrosurgery is one of the most commonly used energy systems in laparoscopic surgery. Two major categories of potential complications related to electrosurgery in laparoscopy are mechanical trauma and electrothermal injury. The latter can result from unrecognized energy transfer in the operational field or, less commonly, to unnoticed stray current outside the laparoscopic field of view. Stray current can result from insulation failure, direct coupling, or capacitive coupling. METHODS: We reviewed the literature concerning essential biophysics of electrosurgery, including electrosurgical waveform differentiation, tissue effect, and variables that determine tissue effect. The incidence of electrosurgical injuries and possible mechanisms responsible for the injuries are discussed. Different types of injuries may result in different clinical manifestations and histopathological findings. Gross and microscopic pathological check-ups of the injury sites may distinguish between different mechanisms, and thus provide further clues postoperatively. RESULTS: Several recommended practices are proposed to avoid electrosurgical injury laparoscopically. To achieve electrosurgical safety and to prevent electrosurgical injuries, the surgical team should have a good understanding of the biophysics of electrosurgery, the basis of equipment and general tissue effects, as well as the surgeon's spatial orientation and hand-eye coordination. Some intraoperative adjuvant procedures and newly developed safety devices have become available may aid to improve electrosurgical safety. CONCLUSIONS: Knowledge of the biophysics of electrosurgery and the mechanisms of electrosurgical injury is important in recognizing potential complications of electrosurgery in laparoscopy. Procedures for prevention, intraoperative adjuvant maneuvers, early recognition of the injury with in-time salvage treatment, and alertness to postoperative warning signs can help reduce such complications.     

Quantifying inadvertent thermal bowel injury from the monopolar instrument

Background

Insulation defects are observed in 3–39 % of laparoscopic instruments. Electrosurgical injuries due to insulation defects or capacitive coupling remain an issue in laparoscopic surgery with a prevalence of 0.6–5 per thousand cases. Shielded instruments with active electrode monitoring (AEM) have been postulated to prevent these injuries. The benefit of these instruments has not been quantified. Most bowel injuries are unrecognized intra-operatively. Injury is revealed only after the patient exhibits peritonitis symptoms and surgical intervention to repair the bowel is required. These injuries may result in devastating and costly complications or mortality. The extent of bowel injury possible with commonly used generator settings and associated energy output has never been histologically defined. Our objectives in this experimental study were: quantify and compare the energy released through insulation defects or capacitive coupling with standard unshielded monopolar versus shielded instruments with (AEM), determine energy required to cause a visible burn, and relate the histological burn depth to a given amount of energy.

Methods

Ex vivo porcine jejunum was used for tissue testing. An oscilloscope measured energy output from three common electrosurgical generators at recommended power settings with standard or AEM instruments with insulation defects and in capacitive coupling scenarios. Presence of a visible burn was noted, and depth of tissue damage for a given amount of energy was measured histologically.

Results

All samples that received ≥3.8 J of energy had visible burns. As little as 10 J caused full wall thickness burns. 3.8 J was exceeded at the 30- and 50-W power settings in every experimental scenario using standard monopolar instruments; AEM instruments never approached this much energy.

Conclusions

Serious burn injury results from small amounts of energy leaked from standard instruments. AEM instruments appeared protective and did not leak sufficient energy to cause burn injuries to the bowel.

     

Active electrode monitoring

Background: In recent years, the use of minimally invasive surgery (MIS) has expanded to a wide variety of surgical specialties. The increased popularity of the procedure, however, has been accompanied by its share of complications, including trocar lacerations and inadvertent thermal injuries to nontargeted tissues during monopolar electrosurgery. Methods: A survey on electrosurgical thermal injuries and three case studies are presented. The new technology of active electrode monitoring (AEM) is described. Results: AEM eliminates stray currents generated by insulation failure and capacitive coupling. Conclusions: To reduce the incidence of injury by monopolar electrosurgery at laparoscopy, there is a need for advanced technology, such as AEM. In addition, laparoscopic surgeons should be encouraged to study the basic concepts of the biophysics of electrosurgery. Received: 26 June 1997/Accepted: 10 December 1997     

Insulation failure in laparoscopic instruments

Background  

Electrosurgery is used in virtually every laparoscopic operation. In the early days of laparoscopic surgery, capacitive coupling, associated with hybrid trocars, was thought to be the major cause of laparoscopic electrosurgery injuries. Modern laparoscopy has reduced capacitive coupling, and now insulation failure is thought to be the main cause of electrosurgical complications. The aim of this study was (1) to determine the incidence of insulation failures, (2) to compare the incidence of insulation failure in reusable and disposable instruments, and (3) to determine the location of insulation failures.     

Stray radiofrequency current as a cause of urethral strictures after transurethral resection of the prostate

PURPOSE: This study was designed to define the pattern and significance of stray currents induced by two electrosurgical generators (ESGs) in relation to urethral strictures forming after transurethral resection of the prostate (TURP). MATERIALS AND METHODS: A 24F resectoscope irrigated with glycine was activated at various power outputs in different modes, with intact loops and loops with faulty insulation, simulating TURP. The Valleylab and ERBE ESGs were compared for inducing capacitance. An ESG analyzer simulated tissue impedance and recorded the stray currents induced along the resectoscope sheath. A fresh pig liver was used for assessment of tissue damage caused by the currents. RESULTS: In the cutting mode, the ERBE ESG produced a mean stray current of 70 mA with an intact loop and 144 mA with a loop having faulty insulation. The Valleylab ESG produced 150 mA and 161 mA, respectively. In the coagulation mode, the ERBE ESG produced an average leakage current of 35 mA and, with a loop with faulty insulation, 40 mA. The Valleylab ESG produced 148 mA and 151 mA, respectively. CONCLUSIONS: Electrical injury may represent a significant cause of urethral stricture after transurethral electrosurgery. The critical power density of 7.5 W/cm2 (which is likely to cause a urethral burn) may be reached, especially with the use of loops with faulty insulation or nonconductive lubricating gel. The ERBE ESG produced significantly less capacitance, decreasing the risk of urethral electrical burn. Conductive gel prevents dangerous current concentration.     

Radiofrequency energy antenna coupling to common laparoscopic instruments: practical implications

Background

Electromagnetic coupling can occur between the monopolar “Bovie” instrument and other laparoscopic instruments without direct contact by a phenomenon termed antenna coupling. The purpose of this study was to determine if, and to what extent, radiofrequency energy couples to other common laparoscopic instruments and to describe practical steps that can minimize the magnitude of antenna coupling.

Methods

In a laparoscopic simulator, monopolar radiofrequency energy was delivered to an L-hook. The tips of standard, nonelectrical laparoscopic instruments (either an unlit 10?mm telescope or a 5?mm grasper) were placed adjacent to bovine liver tissue and were never in contact with the active electrode. Thermal imaging quantified the change in tissue temperature nearest the tip of the telescope or grasper at the end of a 5?s activation of the active electrode.

Results

A 5?s activation (30 watts, coagulation mode, 4?cm separation between instruments) increased tissue temperature compared with baseline adjacent to the grasper tip (2.2?±?2.2?°C; p?=?0.013) and telescope tip (38.2?±?8.0?°C; p?<?0.001). The laparoscopic telescope tip increased tissue temperature more than the laparoscopic grasper tip (p?<?0.001). Lowering the generator power from 30 to 15 Watts decreased the heat generated at the telescope tip (38.2?±?8.0 vs. 13.5?±?7.5?°C; p?<?0.001). Complete separation of the camera/light cords and the active electrode cord decreased the heat generated near the telescope tip compared with parallel bundling of the cords (38.2?±?8.0 vs. 15.7?±?11.6?°C; p?<?0.001).

Conclusions

Commonly used laparoscopic instruments couple monopolar radiofrequency energy without direct contact with the active electrode, a phenomenon that results in heat transfer from a nonelectrically active instrument tip to adjacent tissue. Practical steps to minimize heat transfer resulting from antenna coupling include reducing the monopolar generator power setting and avoiding of parallel bundling of the telescope and active electrode cords.     

Electrophysical properties of electrosurgery and capacitive induced current

BACKGROUND: Although electrosurgery is one of the most commonly used technologies in the operating room, its electrophysical properties, including the potential for complications, are poorly understood by many surgeons. METHODS:We describe the experimental simulation of a highly unusual complication that occurred during a surgical procedure requiring concurrent use of monopolar and bipolar electrosurgery. RESULTS: Capacitive induced current from an activated monopolar electrode to the bipolar cord was reproduced and consistently led to full-thickness burns in our experiments. CONCLUSIONS: Surgeons should be familiar with the principles of electrosurgery, its electrophysical properties, and possible complications.     

Unintended stray energy from monopolar instruments: beware the dispersive electrode cord

Background

The monopolar instrument emits stray radiofrequency energy from its cord when activated. This is a source of unintended thermal injury to patients. Stray energy emitted from the dispersive electrode cord has not been studied. The purpose of this study was to determine whether, and to what extent, the dispersive electrode cord contributes to unintentional energy transfer and describe practical steps to minimize risk.

Methods

In a laparoscopic simulator, a monopolar generator delivered radiofrequency energy to an L-hook. Thermal imaging quantified the change in tissue temperature nearest to the tip of a non-electrical instrument following activation. The orientation of the dispersive electrode cord was varied relative to other instruments.

Results

When the dispersive electrode cord is parallel to the camera cord, tissue temperature increased at the telescope tip by 46 ± 6 °C from baseline (p < 0.001). Similar heat was generated when the camera cord was oriented parallel to the active electrode cord (46 ± 6 vs. 48 ± 7 °C, respectively, p = 0.48). Adding a second dispersive electrode decreased the temperature change (46 ± 6 vs. 25 ± 9 °C, p < 0.001). Temperature increase was greater with coagulation versus cut mode (33 ± 7 vs. 22 ± 6 °C, p < 0.001).

Conclusion

Stray energy emitted from the dispersive electrode cord heats tissue >40 °C via antenna coupling; the same magnitude as the active electrode cord. Practical steps to minimize stray energy transfer include avoiding orienting the dispersive electrode cord in parallel with other cords, adding a second dispersive electrode, and using low-voltage cut mode.

     

Electrical injuries during laparoscopy

Electrical injury is uncommon during surgical laparoscopy, but may be serious. Following a comprehensive literature review, we describe five mechanisms of burn injuries: direct contact, electric arc, insulation failure, direct or capacitive coupling. We discuss these mechanisms and suggest simple preventive measures designed to ensure optimal safety.     

Hemostasia y tecnología. Energía. Desarrollo de las nuevas tecnologías

The hemostasis systems applied in surgery are based on endothermic heat production resulting from the interaction between energy and tissue.The most frequently used energy source is electrocoagulation, applied through two systems: monopolar and bipolar. More sophisticated electrocoagulation systems have progressively been developed such as the Argon beam, in which coagulation is superficial and does not injure the deep tissues, or LigaSure?, based on the use of a bipolar system with an inbuilt feedback system allowing vessels to be sealed without excessive heat and a consequent reduction of collateral lesions.Another system that has been developed in the last few years is the ultrasonic scalpel, based on the ability of the cell membrane proteins to denature as a result of ultrasonic vibration. This system avoids some of the risks involved in the use of electrical energy such as accidental burns due to stray electrical current or faulty insulation of an instrument. Moreover, the harmonic scalpel reaches a temperature of no more than 100° and the effect of lateral tissue destruction is much lower than with electrosurgery, although this reduction is negligible when compared with the electrosurgical methods developed in the last few years such as LigaSure.Another system that is also used is laser energy, consisting of a photon beam containing a specific wavelength; each photon moves in step with the others in both time and space. This system has not become widely used due to its high cost, the difficulty of controlling this type of energy, and the lack of objective advantages over conventional electrosurgery.     

Comparative analysis on the effect of low‐thermal plasma dissection device (PEAK PlasmaBlade) versus conventional electro surgery in post‐bariatric body‐contouring procedures: A retrospective randomised clinical study

Postoperative wound‐healing problems are relatively high in post‐bariatric body‐contouring procedures, partly because of electrosurgery and the associated thermal tissue damage. This study is a retrospective randomised evaluation of the effect of a low‐thermal plasma dissection device (PEAK PlasmaBlade, Medtronic, Minneapolis, Minnesota) in comparison with conventional electrosurgery. A total of 24 patients undergoing upper arm or medial thigh lifting were randomised to PEAK PlasmaBlade on one side and to monopolar electrosurgery on the other side of the same patient. Wounds of 10 patients were examined histologically for acute thermal injury depth. Significantly lower total volume of drain output (61,1 ± 70,2 mL versus 95,1 ± 176,0 mL; P = .04) was found on the PEAK PlasmaBlade side compared with the electrosurgery side. Furthermore, the PEAK PlasmaBlade side showed fewer seromas (no case of seroma versus three seromas in the electrosurgery group) and less thermal damage (40% versus 70%; P = .26). Acute thermal injury depth from the PEAK PlasmaBlade was less than from monopolar electrosurgery (425 ± 171 μm versus 686 ± 1037 μm; P = .631). PEAK PlasmaBlade appears to be superior to traditional monopolar electrosurgery for post‐bariatric body‐contouring procedures because it demonstrated less tissue damage, lower total volume of drain output, and fewer postoperative seromas resulting in faster wound healing.     

The use of stab incisions for instrument access in laparoscopic operations

Background/Purpose: Traditional laparoscopic approaches require cannulas for instrument access to the abdominal cavity. This study reports the authors’ experience using minimal access (MA) stab incisions, rather than cannulas, for insertion of laparoscopic instruments into the peritoneal cavity.Methods: All patients undergoing MA procedures by the authors from November 1999 through March 2003 were included. Procedures included foregut, biliary, adrenal, splenic, colonic, and genitourinary operations. A single cannula was used for insertion of the telescope. In select cases, a second cannula was needed for unique instruments (staplers/ultrasonic shears). Abdominal wall stab incisions (SI) were used for introduction of the remaining instruments.Results: A total of 511 MA procedures were performed during the study period. Pneumoperitoneum was maintained in all cases. There were no complications associated with creation of the SI. A single-Step reposable (partially reusable, partially disposable) cannula and expandable sheath were used in 308 cases, whereas a second-Step reposable cannula and sheath were needed in 203 children. In total, 1,337 cannulas were saved using this MA technique. The cost to the patient was $140/Step cannula and sheath; overall cost savings were $187,180.Conclusions: MA procedures can be performed safely and effectively with a single or, occasionally, 2 cannulas. The cosmetic result is superior, and there are significant cost savings related to the elimination of accessory cannulas. The authors believe this technique of SI for instrument access is superior to the traditional cannula approach and can be utilized in most laparoscopic operations.     

Principles and safety measures of electrosurgery in laparoscopy

Background:

Electrosurgical units are the most common type of electrical equipment in the operating room. A basic understanding of electricity is needed to safely apply electrosurgical technology for patient care.

Methods:

We reviewed the literature concerning the essential biophysics, the incidence of electrosurgical injuries, and the possible mechanisms for injury. Various safety guidelines pertaining to avoidance of injuries were also reviewed.

Results:

Electrothermal injury may result from direct application, insulation failure, direct coupling, capacitive coupling, and so forth.

Conclusion:

A thorough knowledge of the fundamentals of electrosurgery by the entire team in the operating room is essential for patient safety and for recognizing potential complications. Newer hemostatic technologies can be used to decrease the incidence of complications.     

A new technique of internal cardiac cooling improves atrial protection

We developed a technique for selectively cooling the right heart during cardioplegic arrest by intracavitary right atrial (RA) perfusion with cold blood. In dogs during hypothermic cardioplegic arrest, we compared the effects on myocardial temperature of RA perfusion and two snared caval cannulas with three methods of venous cannulation without perfusion: a two-stage atriocaval cannula, two caval cannulas and two snared caval cannulas. The mean atrioventricular (AV) node temperature with RA perfusion (16.5 degrees +/- 0.4 degrees C) was significantly lower than with the atriocaval cannula (25.1 degrees +/- 0.2 degrees C), two caval cannulas (25.2 degrees +/- 0.3 degrees C) or two snared caval cannulas (21.6 degrees +/- 0.2 degrees C) (p less than 0.01, RA perfusion versus other groups). The results for RA wall temperature showed a similar pattern. RA perfusion produced similar results in 6 patients undergoing coronary artery bypass grafting. We conclude that hypothermic protection of the right atrium and AV node is inadequate with conventional techniques of cannulation and cooling, and may be improved by the use of internal RA cooling.     

A Minimalist Approach to Hip Arthroscopy: The Slotted Cannula

Adequate patient positioning with a traction device to provide sufficient distraction of the hip to access the femoral-acetabular joint is the first and most important step in hip arthroscopy. Cannulated instruments provide reproducible access to the hip joint from every portal by following guidewires into the joint. These guidewires are positioned through long spinal needles via fluoroscopic navigation and, subsequently, direct arthroscopic vision. By using these techniques adequately, the risk of iatrogenic damage to the hip joint is reduced. The traditional option for introduction of instruments to the hip joint has been the use of closed working cannulas of increasing diameters to accommodate instruments of different sizes. Curved instruments usually require large-diameter standard cannulas or flexible plastic cannulas. Large cannulas increase the risk of damage to the articular cartilage and may not accommodate every curved instrument. Flexible cannulas may leave debris inside the joint if damaged. Slotted cannulas allow curved instruments to be introduced into the hip joint by sliding them through their open side. With the instrument inside the joint, the slotted cannula can be slid out for better instrument mobility. It can also be reinserted around the previous instrument for instrument or portal exchange.     

APPLICATIONS OF ELECTRICAL ENERGY TO THE PROSTATE: AN EVOLUTIONARY PERSPECTIVE

Purpose

We review modern electrosurgical treatments for removing benign prostatic tissue based on an historical perspective of medical applications of electrical energy.

Materials and Methods

We reviewed historical reports and landmark observations concerning the evolution of medical applications of electrical energy in the literature, with a special focus on the development of principles pertinent to the transurethral electrosurgical removal of prostate tissue.

Results

Modern transurethral electrosurgery of the prostate in a fluid medium has been well founded on key electrosurgical principles. Traditionally, the best clinical results and the least complications have been obtained through an understanding of the important precepts of this form of energy. These precepts have included distinctions between the reliability of effect and safety with direct and alternating current, and how different tissue effects can be achieved, either with selective current modes (cutting and coagulating waveforms) or by varying the size and configuration of the active electrode and its application time.

Conclusions

This review chronicles the prominent role of electrosurgery in our efforts to debulk an enlarged prostate in patients with symptomatic voiding dysfunction. History reminds us that many of today's “new ideas” are merely updated variations on a theme, have often been tried before in a fashion by our predecessors and have for one reason or another fallen by the wayside. The conundrum of the perfect combination of electrosurgical variables that can fulfill our goal of making this an efficient and complication-free treatment continues to stimulate and challenge us as we move towards the next millennium.     

Powered Liposuction

BACKGROUND: Although Arpad and Giorgio Fischer initially employed blades within cannulas in their early research while inventing liposuction, hollow cannulas have become the standard instrument for this procedure for the last quarter century. Ultrasonic liposuction was developed in the 1990s to facilitate the passage of cannulas through subcutaneous tissue while liquefying fat. However, these instruments had a number of drawbacks including seromas and tissue burns. Powered cannulas were introduced in 1995 by Gross for "liposhaving." This technique was used on the neck with open surgery under direct observation. OBJECTIVE: Based on these principles, a new powered liposuction device has been designed for body liposuction. METHOD: An oscillating blade within a cannula facilitates removal of fat, especially in fibrous areas such as male flanks and breasts. This instrument has proven to be safe in numerous body areas. Powered reciprocating cannulas also have been recently introduced. These simulate the "to and fro" motion of manual liposuction and appear to be safe. CONCLUSION: Powered liposuction may provide the advantages of ultrasonic liposuction with fewer complications.