quick notes on lasers, cryotherapy and also glimpses of HBOT, powered instruments and RFA

1. LASERS AND CRYOTHERPY IN ENT
PRACTISE
DR A. MOHAN KRISHNA
SR- DEPARTMENT OF ENT
SSIMS

2. LASER
• Acronym:
– Light Amplification by Stimulated Emission of
Radiation
• Definition
– Laser is a device that produces and amplifies light
by stimulated emission of radiation
– It can produce light in the ultraviolet, visible, and
infrared region of the electromagnetic spectrum

6. Properties of laser light
• Monochromatic
– A single pure color emitted by a single wavelength
• Collimated
– A beam in which almost all the photons are travelling
in the same ‘parallel direction’
• Coherent
– Waves produced by a laser travel through space in
phase which is responsible for the strength and
intensity of the beam between different points in the
field

7. Types of lasers acc. to materials used
• Solid :
– Nd: YAG laser
• Liquid :
– Organic dye laser.( rhodamin 6G , disodium fluorescein)
• Gas :
– Helium Neon (HeNe) laser, CO2,Argon and Krypton Gas
laser.
• Semiconductors :
– Gallium-Arsenide -Diode laser
• Excited dimer (Eximer Laser) :
– Argon fluoride and Krypton fluoride

12. ENT APPLICATIONS
• Argon laser
– Can be delivered by optic fibres
– Vascular lesions - haemangioma, telengectasia
– Ear – stapedotomy, lysis of middle ear adhesions,
tympanoplasty graft
• Diode laser
– 600-1000 nm
– Cheaper
– Turbinate reduction, DCR, tonsillar ablation
– Can be delivered through optic fibres

13. • KTP 532 laser – Potassium-Titanyl-Phosphate
– Use in endoscopic surgery through hand held probe,
delivered through optic fibres
– Ear – stapedotomy
– Nose – FESS, epistaxis, turbinate reduction,
telengectasis
– Oral cavity – leukoplakia, erythroplakia, T1 lesions,
advanced tumours for debulking, SMF for treating
trismus, UPPP
– Larynx – MLS, T1 ca, laryngocele, stenosis
– Bronchoscopy – to remove tracheobronchial
secretions

14. • Nd:Yag laser
– Neodymium:Ytrium-Aluminium-Garnet
– Colourless, can pass through optic fibres
– Coagulative, but poor precision – can cause damage
to surrounding tissue
– Can be used along with CO2 laser
– Obstructive- malignancy trachea, bronchi, oesophagus
– Vascular lesions like telengectasia
– Lymphangioma
– Turbinate hypertrophy

15. • CO2 laser (MC in ENT )
– Carbon dioxide
– Medium used – mixture of co2, nitrogen and helium
neon gases
– Colour – red light of helium neon
– Good precision
– Cant pass through flexible endoscopes so need
articulating arm
– Can be attached to microscope making hand free
– Vaporizes tissue

16. • Ear
– Stapedotomy, acoustic neuroma
• Nose
– Telengectasia, rhinophyma, choanal atresia, turbinate
hypertrophy
• Oral cavity
– Leukoplakia, erythroplakia, small sup cancers, debulking of large
tumours
• Oropharynx
– Recurrent tonsillitis, T1 tumours
• Larynx
– Papillomas, webs, stenosis, leukoplakia of cord,
arytenoidectomy, T1 ca
• Trachea and bronchi
– Debulking of malignant tumours

17. Advantages of lasers
• Easy and rapid ablation of tissue
• Excellent haemostasis
• Little surrounding tissue damage
• Minimal post op pain and oedema due to
action on peripheral nerves
• Faster post op recovery
• Blocks lymphatics so prevent metastasis

18. Disadvantages of lasers
• High cost of purchase and maintenance
• Need special training
• Biopsy cant be taken
• Hazards – ET tube fire, electric shock, eye injury,
skin injury
• Chemical hazards, plumes (vaporized cell
contents)
• Damage to vocal cords
• Tracheal perforation

19. Safety precautions
• Education and training of staff including surgeons,
anaesthesists, nursing, technicians
• Protection of eyes -Eye glasses with side protection and
different colours (Nd:Yag – blue, co2- plain) worn by
those working in OT.
• Patient eye covered with double layer of saline soaked
eye pads/bands
• Protection of patient skin by saline soaked towels,
pads, sponges which are moistened periodically
• Evacuation of smoke produced by laser vaporization of
tissue by using 2 suctions – 1 for blood and mucus
other for smoke and steam

20. Anaesthesia gases and equipments
• Prevention of ET tube fires
• Use only non inflammable gases like halothane
(safest) or ether
• Use red rubber or silicone tube wrapped with
reflective metallic (aluminium) foil, protected
with saline soaked cotton
• Cuff of tube inflated with saline water coloured
by methylene blue – warns during leakage of cuff
• Use jet ventilation with no cuff

21. ET tube fire
• Immediately stop ventilation, pour saline with
syringe and remove tube.
• Restore airway with new tube.
• Give IV steroids
• Perform repeated bronchoscopies to ascertain
damage
• A bowl filled with saline and a syringe should be
kept in table while using lasers
• Laser OT should be labelled and isolated with no
entry or exit allowed except ot staff

22. PHOTODYNAMIC THERAPY
• Procedure :
– Injection of photosensitizing agent – DHE
(dihematoporphyrin ether) IV into malignant site and
exposing the site to lasers (argon laser) -> activates the
agent leading to destruction of cancer cells and sparing of
normal tissue
• Indications
– Treatment of ca larynx, nasopharynx, aerodigestive tract
and endobronchial region
– Recurrent ca after CT/RT/surgery
• Side effects:
– Photosensitivity so wear sun protective clothing on
exposure to sunlight

23. CRYOSURGERY
• Rapid cooling or freezing of tissues at v low temperature
at -30 degree celsius followed by slow thawing leads to
destruction of tissues
• Types
• Open system
– Direct application of refrigerating chemicals like liquid
nitrogen sparay, co2 snow
• Closed system
– Using cryoprobe ( available in various sizes and designs and
produces tip temperature of -70 degree celsius)
• Based on Joule Thomson principle – rapid expansion of
compressed gas through a small hole produces healing
• Gas used are – liquid nitrogen, nitrous oxide, co2

24. • Pathology : Tissue destruction by
– Intracellular dehydration,
– Denaturation of lipoproteins, thermal shock,
– Vascular stasis of arterial and venous blood and
– Cryoimmunisation (formation of antibodies
against tissues)

25. • Indications
– Head and neck tumours
– Benign vascular lesions
– Premalignant lesions
– Reduction of turbinates, allergic rhinitis
– Tonsillitis
– Herpetic, apthous ulcers in oral cavity
– Meniere’s disease
– Rhinosporodiasis
– Nasal polyp
– Epistaxis

26. Procedure
• Anaesthesia – LA/ sedation/ no anaesthesia as
tissue freezing causes numbness
• Cryoprobe applied for 2-8 minutes leading to
rapid freezing
• Freezed tissue allowed to thaw slowly
• Procedure repeated once or twice
• Healing by secondary intention with necrotic
stump fall in 3-6 weeks

27. Advantages
• Safe procedure
• No need for GA
• OPD procedure
• No excision needed
• Low cost
• Minimal side effects
• Can be tolerated by elderly
• Manage patients with bleeding disorders - No
haemorrhage

28. Disadvantages
• Excision biopsy not possible
• Cant assess margins of tumour
• Need multiple sittings
• Depth of freezing unpredictable
• Causes skin pigmentation and loss of hair –
due to destruction of hair follicles
• With lasers decline in use

29. RADIOFREQUENCY ABLATION
• Principle
– Use of electromagnetic waves of high frequency
through a hand held probe which is inserted into
tissues -> cuts and coagulates tissues with minimal
normal tissue damage and scarring
– OPD procedures with fewer complications
• Indications
– Inferior turbinoplasty
– Surgery on soft palate for sleep apnoea and snoring
– Surgery on base of tongue for snoring, lingual thyroid,
Tonsillectomy, MLS, Rhinophyma excision

30. HBOT(HYPERBARIC OXYGEN THERAPY)
• Intermittent inhalation of 100% oxygen in chamber with
pressure above 1 ATA (atmospheric absolute)
• Indications
– Adjunct treatment of sudden SNHL – patients with ssnhl > 41 db
within 14 days of onset of symptoms – 100% oxygen at 2-2.5 ATA
for 90 minutes daily for 10-20 sittings (6 sittings/ week) –
increases amount of oxygen in tissues by diffusion
– Tinnitus
– Noise induced hearing loss/ acoustic trauma
– Malignant otitis externa
– Non healing wounds
– Compromised skin grafts and flaps
– Crush injury
– CO poisoning
– Decompression sickness

31. POWERED INSTRUMENTS
• MICRODEBRIDER
• COBLATION(COLD ABLATION)
– Electro-dissociation procedure
– 400-700 C
• HARMONIC SCALPEL
– Coagulation using ultrasonic vibrations(55.5kHz)
• TCRFA(TEMP. CONTROLLED RADIOFREQUENCT
ABLATION)