SURGICAL DIATHERMY

DIATHERMY: Used during cutting and coagulation of the tissues Consists of high frequency power oscillators Spark gap oscillators Undamped current: clean cutting Damped current: coagulation

Electro surgical unit:

Requirement: High temperature exceeding 1000 degree C 1 mm diameter of cross section of arc High current density Frequency : 250 Hz to 1 MHz Cutting : 400 W Coagulation : 150 W (10-15 s & 15 KHz)

Block diagram: Control panel & logic board: produces the basic signal and timing informations Operates the relays, give visual indications and determine the alarm conditions Isolated and carefully insulated Avoid contact to conducting surfaces.

Automated electro-surgical systems: Size and shape of cutting electrode Type and speed of cut Tissue properties Voltage control or spark control Programmed processors decides the spark intensity

Contd. Soft coagulation: no electric arcs, prevents skin from carbonized Forced coagulation: arcs are intentionally generated between the coagulation electrode and the tissue (deeper coagulation) Spray coagulation: arcs are deliberately produced. Contact is not necessary

Electro surgery techniques: Mono polar technique: depends on the contact area Bi polar technique : two electrodes. Contact area is less. Safer and precise.

Electrodes used: Needle electrode: desiccation lancet electrode: cutting Loop electrode : ecsecting (opening) the channels, extirpating growth Performance: improper placement of electrode Loss of energy ( Mono phasic electrode)

LASER Physiotherapy and electrotherapy equipments Heat radiation by the application of high frequency radiation (through heating) Muscles, bones, internal organs etc. Polarity of the electric field alters, continuous re-alignment of the molecules Microwaves and ultrasonic waves are used for heating purpose

Short wave diathermy: Hot towels, infrared lamps, electric heating pads Heat is produced within the body rather not transferred through the skin (to avoid discomfort and skin burns) Can be controlled precisely AC frequency : 27.12 MHz ( no muscle contraction)

Circuit diathermy and automatic tuning: Page no: 762 Anode voltage: 4000 V Controlling the anode voltage, filament heating current Adjusting the grid leak resistance, R1.

Application technique: Capacitor plate method: Tissues are kept sandwiched between the two pads No direct contact Also called as Condenser method

Contd. Inductive method: The cable is coiled around the arm RF current is passed and the magnetic field applies the heat (electro static action) Also called as inductohermy

Diapulse therapy: Increase in energy output avoids the dangers of heat Pulse width : 65 micro second Interval : 1600 micro second

Micro wave diathermy: Frequency : 300 to 30,000 MHz (2450 MHz) Wavelength : 10 mm to 1 m (12.25 cm)

Contd. Delay circuit Magnetron circuit Safety circuit

Ultrasonic therapy unit: Absorption property of the tissues Piezo electric effect

Contd. Controlling the firing angle Frequency of ultrasound Intensity of ultrasound Duration of exposure Avoids injury

Apparatus: Galvanic current: Steady flow of current 10-20 minutes

Contd. Exponentially progressive current: Independent pulse duration

Contd. Faradic current: Sequence of pulses With defined shape and current 80 mA of magnitude 25 surges per minute

Functional diagram:

Contd. Distortion free Irrespective of patient’s resistance Position of the electrodes should be rigid Mono-polar electrode : indifferent electrode is placed near to the active electrode.

Transcutaneous electrical nerve stimulator: Gate control theory: prevents pain carrying messages Endorsphin release theory: stimulation of pain killing substance (Endorsphin)

Spinal cord stimulator: Not for patients using triggered or inhibited type of pacemakers

Magnetic stimulator: Electrical stimulator is very painful Magnetic pulse is generated by passing a brief, high-current pulse through a coil of wire Still experimental

Diaphragm pacing by radio frequency for the treatment of chronic ventilatory insufficency: Only one phrenic nerve could affect normal oxygen and carbon-di-oxide exchange

Contd. Bladder stimulators: Reflex actions can be controlled Possible kidney malfunction Cerebellar stimulators: Inhibiting intractable epilepsy