Dr.S.Harsha Vardhan
Electrosurgery - use of radiofrequency alternating current to vaporize or coagulate tissue.
Cautery (Kauterion = hot iron) - destruction or denaturation of tissue is by passive transfer of heat or application of caustic substance
Technology growth
Effective use in Laproscopic Surgery > Open Surgery
Thorough understanding & Proper knowledge of usage for ‘Safe Surgery’
Weapons in unskilled hands
4 forms – 1. Electrical2. Ultrasonic3. Argon Beam4. Laser
Oldest & widest usage
Mentioned in ancient medicine – 3000 BC
Fire Drill
Rapid turning of instrument to produce heat
Used as cautery to control bleeding
Hippocrates used it for Hemorrhoids treatment
Initially using ‘Single’ electrode
Later usage of ‘Two’ electrodes
Flows in – Path of ‘Low’ resistance
Always seeks to return to ground (-ve pole)
Current (I) - measure of the electron moment past a given point in the circuit in a fixed period of times ~amperes
Voltage (V) - pressure with which the electrons are pushed through the tissue ~volts
Resistance (R) - measure of the difficulty that a given tissue presents to the passage of electrons~ohms
Power (W) - capacity to do work per unit time~watts
Ohm’s Law , i=V/R
DC
AC – Alternate flow of electrons– Hertz/Cycles per second
- Normal is 60Hz- ElectroSurgical Unit – 60Hz to 500 KiloHz
Converts a 60 cycles / sec (60 Hz), lowvoltage alternating current into higher voltage radio frequency (500 KHz - 3.0MHz) current.
Current flow – Least Resistant Path
Tissue with More Water Content
Blood Nerve Muscle Adipose Bone
Dessicated tissue ‘Non-Conductive’
Surrounding tissue damage
Electrocautery – Instrument to heat tissue
Electrosurgery – Current flows through tissue to produce changes
Circuit to be completed
From Active elctrode
Ends in Passive electrode
MonoPolar Cautery
Advantages – - Easy to use- For tissue dissection- Greater tissue penetration- Area of Coaguation > BiPolar
Disadvantages –- Larger volume of tissue injured- Can interfere with pacemakers- Requires distant return electrode
Tissue effects of R.F.Electrical Current –- Vaporization or cutting- Desiccation or coagulation- Fulguration - High voltage modulated
current with a short duty cycle
Vaporization and fulguration - Non contact procedures
BiPolar Cautery
2 arms in hand piece
Damage to tissue b/n 2 electrodes
Tissue damage inc. Tissue resistance
Dec./no damage to surrounding tissue
Advantages- Dec. Thermal injury to surrounding tissue- Works well in saline- In Pt with Pacemaker- Dec. Risk of capacitive coupling
injuries
Disadvantages- More skill- Coagulation only- No dissection capabilities
50-80℃ = Tissue coagulation
Around 100℃ = Dessication & Vapourisation
200-300℃ = Tissue Carbonisation
Amount of heat generation depends on - amount of tissue in contact with electrode (similar to pressure
principle)
Short duration , High Voltage – Coagulation due to rapid tissue heating
Low Voltage , High wattage current – Tissue cutting
Reduced bleeding
Preclution of germ implantation
Avoidance of mechanical damage to thetissue
Endoscopic applicability
Endogenous burns Exogenous burns Pseudo burns Active Electrode Trauma Current diversion Alternate ground site burns Direct coupling Indirect coupling Capacitive coupling Dispersive electrode burns Smoke inhalation
Uses high frequency vibrations
Harmonic – for delivering precise energy for better vessel sealing
capabilities
- upto 7mm vessels Harmonic Scalpel – Vessel sealing &
transecting capabilities
Work at 55KHz
Uses high-frequency mechanical vibrationsto fragment tissue
Used in ophthalmic, neuro, hepato-biliaryand oncologic cytoreductive surgery
Fragments tissue by contact with high water content cells
Vibration generate vapor pockets within the cells that lead to disruption and fragmentation
Produces vibrations at 55.5KHz at the tip ofthe blade via a hand piece transducer
The moving blade couples with the tissue
resulting in breakage of protein hydrogen bonds and thus protein coagulum forms
Can perform cutting and heamostasis with minimal damage
Limited lateral spread and thermal injury
No electrical energy transferred to patients
Uses a spray of ionized argon gas as the active electrode rather than a metallic blade
Allows even, efficient and broad application of the coagulating current to the tissues
Ideal for obtaining haemostasis along the cut surface of the liver following hepatic resection
Light Amplification by Stimulated Emission of Radiation
Differs from regular light in the following properties –- Coherence (waves are synchronised or in phase with each other)- Monochromaticity (single wavelength)- Collimation (all light waves in parallel , so single beam)
Lasers primarily being used for surgery
- Carbon Dioxide- Nd:YAG (Neodymium-doped Yittrium Aluminium Garnet)- Argon- Ho:YAG (Holmium-doped
Yittrium Aluminium Garnet)- KTP (Potassium Titanyl
Phosphate)- Diode
Ligasure – BiPolar Vessel Seal Device- Combination of pressure &
energy source to enable vessel seal
Rachet grips vessel tightly
Measures resistance in adipose tissue & sent to generator
Delivers energy in pulsed manner
Continues till vessel sealed
Vessels upto 7mm with 3times normal systolic pressure
Gyrus PK Generator –- Pulsed radiofrequency energy
Grasp , dissect , coagulate , vapourise , resect , hemostasis
Intermittent delivery of energy
No charring or sticking of tissue
Enseal RF System –- adjust dose energy simultaneously accounding to the impedence of tissue
- millions of nano sized conductive particles in temperature sensitive material
- sealing arteries , veins , transecting adipose tissue , ligaments & connective tissue
Hydrojet Device –- Jet of water for dessection of
tissue
- Liver parenchyma , Renal hilar dissection
- No thermal injury
Floating Ball : Cutting & Hemostatic Energy
- Monopolar current combination with water cooled and RF
energy
- Blunt dissection , Coagulation
- Radiofrequency current close to tip sealing small vessels
- Current passes through saline and converted to electrical energy at tip of instrument
- No scar formation , as cooled by saline
- upto 3mm vessels coagulated