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