PREVENTION OF COMPLICATIONS BY ENERGY SOURCES
Friday, 04 February 2011

 

 

 PREVENTION OF COMPLICATIONS BY ENERGY SOURCES

 

 

 

                Operative laparoscopy has become widely accepted today and as more and more surgeons adopt this form of management, the complication rate is expected to rise.

 

 

 

                The application of energy systems in laparoscopy has expanded the laparoscopic surgeon’s ability to perform complex surgeries with the capability to rapidly divide tissues and maintain haemostasis. Each energy source capable of destroying tissue can, in specific circumstances, lead to a surgical complication that may be unique to that energy source.

 

 

 

                Every surgeon should understand the basic physics, the uses, applications and limitations of various energy systems and also be aware of potential hazards while using these energy sources.

 

 

 

MONOPOLAR ELECTRO SURGERY

 

 

 

                Monopolar electrosurgery has been used successfully during operative laparoscopy for over sixty five years. It is popular due to its easy availability, low cost and its versatility in a wide range of surgical settings. It can be used for cutting (vaporization), deep coagulation (desiccation) and superficial coagulation (fulguration), depending on variables such as power settings, electrode configuration (sharp edge or blunt surface) and the electric waveform used (continuous or intermittent).  

 

 

 

 

 

 

 

 
Monopolar instruments use current that flows from an active electrode, through tissue having a cutting or coagulating effect. Current further travels through the patient along the path of least resistance, exiting by way of a return electrode plate (usually placed on the patient's thigh) to the electrosurgical unit (ESU).

 

 

 

Complications that can occur during monopolar electrosurgery –

 

 

 

·         Skin burns at the site of return electrode or ECG chest electrodes.

 

 

 

·         Skin burns on hands or face of surgeon.

 

 

 

·         Port site skin burns.

 

 

 

·         Electric burns to vital organs especially bowel.

 

 

 

·         Lateral heat spread to adjacent tissues e.g. ureter.

 

 

 

·         Tissue becoming adherent to the electrode during contact coagulation.

 

 

 

·         Smoke accumulation in the operative field.

 

 

 

·         Perforation of uterus during operative hysteroscopy.

 

 

 

·         Accidental burns to the vagina and perineum while using resectoscope.

 

 

 

                Thermal injury to organs such as bowel or ureter during the use of monopolar electrosurgery could be due to the following reasons:-

 

 

 

1) The surgeons may directly burn non targeted internal organs with tip of active electrode due to imprecise movements of the laparoscopic instrument (“pilot error”).

 

 

 

                Sparking and arcing i.e. jumping of current from the active electrode, through the gaseous environment to unintended tissues can result in injuries. This happens when the generator is keyed before the electrode touches the target tissue, especially when a high voltage COAG current is used.

 

 

 

2) Stray electrical currents emanating from the laparoscopic instruments can inadvertently burn non targeted tissues beyond the surgeon’s limited field of vision. This can occur regardless of the surgeon’s skill and judgment, due to

 

 

 

·         Direct coupling

 

 

 

·         Insulation failure

 

 

 

·         Capacitive coupling

 

 

 

                Direct coupling occurs when the active electrode touches another metal instrument (e.g. laparoscope, suction cannula, needle holder or a trocar sleeve within the abdomen, transferring the energy to the second instrument and possibly injuring tissue with which it comes in contact.

 

 

 

                Insulation failure occurs when the insulated shaft of the electrode becomes compromised due to excessive voltage, poor handling during disinfection & sterilization and mechanical tear due to sharp edges within the cannula. Breakdown of insulation allows electrical current to leak into surrounding non targeted tissues causing thermal damage to unobserved organs. Small cracks are more dangerous because the current is more focused and therefore more likely to cause burns.

 

 

 

                 Capacitive coupling is a phenomenon which occurs when two conductors in close proximity, each insulated from one another, induce an electric current from one ( the active electrode ) to the other conductor, e.g. the operating laparoscope becomes a capacitor when monopolar energy with a high voltage interrupted current ( COAG waveform) is transmitted though a long insulated active electrode. If a trocar sleeve of non conductive (e.g. plastic or fiberglass) material is used to transport the operative laparoscope into the abdomen, the induced current remains isolated, and the laparoscope cannot deliver the induced energy via the abdominal wall to the return electrode. In this case, if a vital structure, such as bowel, touches the laparoscope, the energy induced in the laparoscope can burn the organ. This usually occurs outside the view of the laparoscopic surgeon. Similar problem can occur when 
a secondary trocar sleeve of metal with a plastic collar is used to transport a monopolar electrode.

 

 

 

3) Lateral spread of heat occurs when the tissues are heated. When coaptive coagulation of tissue is done with a conductive clamp, as current is applied, the tissue in the grasp of the clamp is gradually heated until it becomes thoroughly desiccated. Desiccation is complete when tissue whitens and visible steam emission stops. If application of current continues, the heat spreads well beyond the target tissue. Lateral spread of heat to adjacent tissues can cause thermal damage to vital structures e.g. ureter & colon.

 

 

 

BIPOLAR ELECTROSURGERY

 

 

 

                Bipolar electrosurgery was used by most laparoscopic surgeons by 1980. Bipolar electrosurgery incorporates an active (efferent) electrode and the return (afferent) electrode into a two poled instrument such as forceps & scissors. This permits desiccation that is confined to the shape & size of forceps in contact with the tissue. It eliminates the need for a ground plate and also eliminates the chance of stray or alternate pathways. With the bipolar electrosurgery only a CUT or continuous waveform should be used.

 

 

 

                The newer impedance-controlled bipolar systems deliver bipolar energy that senses tissue impedance to perform controlled energy delivery. The total energy delivery is less, thus reducing the sticking and charring to surrounding tissues, and minimizing the lateral thermal spread. These devices use pressure and pulsed current to seal vessels and can effectively seal vessels up to 7mm diameter. Ligasure (Valleylab), Plasma Kinetic dissecting forceps (Gyrus-Medical) & Enseal (Surgrx) are some of these bipolar vessel sealing devices.

 

 

 

Complications that can occur during use of bipolar electrosurgery –

 

 

 

1)      Lateral thermal spread beyond the electrical limits of the instruments occurs if application of current is continued even after the tissue is completely desiccated.

 

 

 

2)      If COAG (intermittent) current is used, the high voltage limits coagulation to superficial layers of the tissue. The deeper tissues are not desiccated because of accelerated build of tissue resistance from rapid desiccation and carbonization of superficial tissues.

 

 

 

In such cases, though pedicles may appear to be completely desiccated, they may bleed when cut.

 

 

 

3)      Tissue between the electrodes of a bipolar instruments may become adherent during desiccation. Repeated attempts to shake the tissue free may lead to traumatic avulsion of a vascular pedicle.

 

 

 

4)      Accumulation of steam and smoke decreases the visibility during a laparoscopic procedure. 

 

 

 

Prevention of complications due to electrosurgery –

 

 

 

The laparoscopic surgeon should follow some basic principles of safety while using electrosurgery.

 

 

 

1) Use of monitored return electrode system (REM system) is preferred. These use disposable return electrodes (ground pads), which are usually composed of two conductive pads placed side by side. Built in monitors measures the pad to skin contact stability. If there is poor contact to the patient leading to higher current density at the area of contact, an alarm sounds and the generator output is automatically terminated. The return electrode pads should be placed close to the operative site on a non dependant, clean, dry, shaved area, avoiding bony prominence and scar tissue. In gynecological surgeries the thigh is preferred.

 

 

 

 2) Never use metal towel clips to attach cables to drapes as leakage of current can cause skin burn.

 

 

 

3) Inspect instrument insulation before each use.

 

 

 

4) If a patient has a pacemaker, consider using bipolar electrosurgery.

 

 

 

5) Select the lowest power settings that will create the desired effect. Usually power setting of CUT current at 70W & COAG current at 50W is sufficient.  If the usual power settings are inadequate, do not increase the power until the circuit and the contact of the return electrode is checked.

 

 

 

6) Activate CUT for all desiccation procedures by monopolar or bipolar electrodes. Use COAG for fulguration procedures.

 

 

 

7) Place electrodes in a safety holster when not in use.

 

 

 

8) Disconnect electrodes from the generator when they are not needed for energy delivery and are used only for dissection.

 

 

 

9) To prevent accidently touching the bowel with an active electrode and also to prevent direct coupling of energy to the laparoscope, the surgeon should withdraw the laparoscope from the operative field to maximize the panoramic view before keying the generator.

 

 

 

10) The risk of capacitance and its complications can be reduced by using a metal trocar sleeve to transport an operating laparoscope into the abdomen. In this case the induced current is transferred through the metal sleeve to the abdominal wall of the patient and finally back to the return electrode.

 

 

 

The secondary trocar sleeve should always be an all-metal or an all-plastic material. Never mix plastic with metal (hybrid trocar sleeves).

 

 

 


11) An active electrode monitoring (AEM) device is a cannula that surrounds the electrode shaft and shunts all capacitance coupled current directly to the return plate. If there is break in the insulation of the electrode, this device alerts the surgeon with an audible alarm. Even the most skilled surgeon, following the strictest safety procedures, may inadvertently burn non targeted tissue during laparoscopic electrosurgery due to the nature of the electrosurgical environment. AEM is a newly available technological solution to this problem.

 

 

 

 

 

 

 

12) Unwanted lateral thermal spread during monopolar or bipolar coagulation can be minimized by terminating the flow of current at the end of the visible vapour phase and applying current in a pulsatile fashion to permit tissue cooling. Pedicles should be secured as a step wise process, desiccation small volumes of tissues alternately with incremental cutting.

 

 

 

11) Before taking any electrosurgical action to control bleeding, accurately determine the source of bleeding and its proximity to vital anatomical structures. Identify bleeders by combining mechanical tamponade or with active hydrolavage. If the bowel, bladder or ureter is in close proximity to the bleeder, mobilize that structure sufficiently before applying energy.

 

 

 

12) While using bipolar electrosurgery, if the tissue between the electrodes become adherent, the stuck pedicles can be usually unglued by energizing the opened device while immersed in a conductive irrigating solution, such as saline.

 

 

 

13) Smoke during electrosurgery can be reduced or eliminated by irrigating the field to be coagulated with glycine or sorbitol. Energy is applied during tissue submersion. In a liquid medium, smoke does not develop. Glycine does not allow dispersion of energy within the medium.

 

 

 

14) Coaptive sealing of the uterine vessels using any type of monopolar current may be ineffective if the blood flow remains uninterrupted. Unless a vessel is sufficiently squeezed before electricity is applied, current density is reduced by conduction in blood, and any heat is dissipated by convection. Bipolar cautery is recommended for these larger pedicles.

 

 

 

15) Accidental burns to vagina and perineum during monopolar resectoscopic surgery occurs from defects in electrode insulation, when interrupted (COAG) current is used, cervix is over dilated and is in contact with less than 2 cm of the outer sheath. Such injury is common if a high electrical force is created by open circuit activation and prolonged activation along already desiccated tissue. Adequate precautions should be taken to avoid above factors which increase chances of genital burns.

 

 

 

LASER ENERGY

 

 

 

                In 1978 Bruhat used CO2 laser for the first time with the operative laparoscope. The term LASER is an acronym for Light Amplification by the Stimulated Emission of Radiation. Laser energy interacts with tissue causing biologic photochemical or thermal reactions. Thermal reaction is the primary tissue effect of surgical lasers used in gynecology. Laser has the ability to vaporize, cut and to varying degrees coagulate tissue. Surgical Lasers available for gynecologic use include CO2, Argon, Potassium-Titanyl-Phosphate (KTP), Neodymium; Yttrium Aluminum Garnet (NdYAG) and Holmium YAG lasers.

 

 

 

                Fiber lasers e.g. NdYAG and Holmium YAG are useful in hysteroscopy as they can be used through fluid distending media. They have been used for transection of uterine septa and adhesions, excision of sub mucous fibroid polyp and for endometrial ablation. During laparoscopic surgery, they produce fewer plumes, give better hemostasis and are less cumbersome to use than CO2 or Argon laser.

 

 

 

                CO2 laser is used for operative laparoscopy procedures like adhesiolysis, fimbrioplasty, vaporization, fulguration and excision of endometrial implants and for salpingectomy for ectopic pregnancy. It is ineffective for deep coagulation of vascular pedicles like uterine and ovarian vessels. Thus laser cannot be considered as a complete energy system for operative laparoscopy by itself.

 

 

 

Complications that can occur during the use of surgical lasers –

 

 

 

                Laser surgery is associated with potential health and safety hazards. Laser hazards to operating room personnel and patient include accidental exposure from misdirection of the laser beam.

 

 

 

·         The eye is the organ most vulnerable to damage by laser. Injury to retina, cornea and lens may occur.

 

 

 

·         Skin injury can occur from ignition of flammable materials by the laser beam.

 

 

 

·         Vaporization of tissue during laparoscopic surgery produces smoke which reduces the visibility of the operative field and has potential health hazards.

 

 

 

·         YAG laser energy delivered by a bare fiber is dangerous for use in the abdominal cavity because of the deep penetration of the YAG beam and the danger of injury to organs below the surface.

 

 

 

 

 

 

 

Prevention of complications during laser surgery-

 

 

 

 

 

 

 

1)       Laser hazards to operating room personnel can be reduced by using the “standby” mode when not actually operating.

 

 

 

2)      Protection of eyes with spectacles or goggles to filter out the specific laser wavelength while transmitting visible light is necessary.

 

 

 

3)      It is important to remove smoke from the closed abdominal cavity during laparoscopic surgery so as to allow the surgeon to see clearly and to remove it from inhalation by the operating room personnel. Careful evacuation and filtration of the laser plume will reduce any hazard of laser smoke inhalation. Special masks provide additional respiratory protection.

 

 

 

               

 

 

 

                Lasers are unique and useful tools in the hands of trained surgeons but they cannot be used to accomplish all surgical tasks. The Laser instruments are also much expensive. The cost of laser instruments, the potential of laser energy for health hazards and the development of more sophisticated electrosurgical instruments has decreased the popularity of laser surgery.

 

 

 

 

 

 

 

ULTRASONIC ENERGY

 

 

 

               

 

 

 

                High Power Ultrasonic Systems like the Harmonic Scalpel and the Autosonix System are used extensively in advanced laparoscopic surgery. Harmonic Scalpel is a device which transforms electrical power into mechanical longitudinal vibrations (at 55,000 times per second) of the working part of the instrument by a piezoelectric transducer situated in the hand piece.

 

 

 

 

 

 

 

Advantages with the use of Harmonic Scalpel during laparoscopic surgery –

 

 

 

·         The Harmonic Scalpel blade provides precise cutting and coagulation with minimal tissue damage and at lower temperatures (less than 100 degree Celsius).

 

 

 

·         Less charring and desiccation of the blood vessels. Tissue planes can be clearly and sharply visualized at all times.

 

 

 

·         Less lateral thermal damage.

 

 

 

·         Absence of tissue sticking to the blade.

 

 

 

·         Minimal smoke and a clearer visual field.

 

 

 

·         No electrical energy passed to or through the patient and hence no exposure to its complications.

 

 

 

·         Cutting and coagulation occurs at the same time, with the same instrument. Hence there is less change of instruments during surgery and reduced operating time.

 

 

 

Limitations of Harmonic Scalpel –

 

 

 

·         The Harmonic scalpel can effectively coagulate vessels of 3-5mm. The coagulation process is slower than that of electrosurgery and there can be hemorrhages after insufficient coagulation. It is not reliable to provide coagulation for larger vessels.

 

 

 

·         High cost of the disposable hand instruments.

 

 

 

Complication that may occur during ultrasonic surgery –

 

 

 

             There have been rare cases where acoustic energy coupling and overheating of the laparoscopic blade with bending of the instrument has occurred. This can happen with steering of the blade extender during surgery and when the instrument is activated for more than 10 seconds. This exposes the adjacent tissues to thermal damage. 

 

 

 

             Proper understanding of the applications and use of Harmonic Scalpel at various settings helps in prevention of mishaps during ultrasonic surgery.

 

 

 

OTHER ENERGY SOURCES

 

 

 

             The Argon Beam Coagulator, Radiofrequency Ablator, and Cryosurgery are other energy sources that are being used during laparoscopic surgery but are not popular in our field and hence not discussed.

 

 

 

             Many energy sources are available to cut, coagulate and vaporize tissues during laparoscopic surgery. Just as physicians are expected to understand and prescribe drugs in a precise and logical manner, so should the surgeons have a working knowledge of the energy sources they choose to use in surgery. The surgeon must realize that the use of a specific energy source does not in itself lessen the chance of a complication. Each energy source has a unique property that determines its effectiveness and limitations when used during minimal invasive surgery.

 

 

 

             What is also true is that a particular surgeon may be conversant or may have mastered a particular technique which may not be familiar to another. Thus it should be pointed out that “It is not the wand but the magician which makes the magic work.”

 

 

 

 Dr. Anuja Vishvas Kulkarni                                                                                                                                                                                                                                                           Mamta  Mamta Hospital, Latur