this slide is about scope and dimensions of laser in the field of otorhinolaryngology.

1. LASER IN ENT
Dr. Prajwal Sharma
2nd year Resident, Dept of ENT
NGMC, Kohalpur

2. INTRODUCTION
• Laser – Light Amplification by Stimulated Emission of Radiation
• Surgical lasers are devices that amplify light and create coherent light beams
ranging from the infrared to the ultraviolet parts of the spectrum.

3. HISTORY
• In 1917, Albert Einstein described the
theory of stimulated emission that is
the underlying process for laser
action.

4. HISTORY CONTD.
• The American physicists, Arthur
Schawlow and Charles Townes,
described the working principles of
lasers in 1958.

5. HISTORY CONTD.
• In 1960 Theodore Maiman
demonstrated the first laser
action in solid ruby and a year
later Ali Javan built the first
helium-neon gas laser.

6. HISTORY CONTD.
• C Kumar N Patel introduced the
carbon dioxide (CO2) gas laser in
1962. In 1972, in Boston, USA,
Jako and Strong were the first to
pioneer the use of the CO2 laser in
otolaryngology, head and neck
surgery.

7. PRINCIPLES OF LASER ACTION
• The electrons in the atoms of a laser medium are first pumped or energized to an
excited state by an external energy source.
• These electrons are then stimulated by external photons to emit their stored
energy in the form of photons.
This process is ‘stimulated emission’

8. • These photons now strike other excited atoms to release even more photons.
• Move back and forth between two parallel mirrors triggering further stimulated
emission--- ‘light amplification’.
• One mirror in the laser tube is partially silvered and it allows the exit or leak of the
intense, collimated, monochromatic and coherent laser light

9. PROPERTIES OF LASER BEAM
 Coherent – photons or waves travel phase with one another
 Collimated – laser beam travels in one direction
 Monochromatic – one wavelength or colour
(Scott-Brown, 8th ed.)
(Image: Cummings, 6th ed.)

10. TYPES OF LASER
Classified according to the type of laser medium used:
1. Solid state - Neodymium tyttrium aluminium garnate (YAG)
- Potassium titanyl phosphate (KTP)
2. Gas - Carbon dioxide laser (CO2 laser)
- Argon laser
- Helium-neon laser
3. Semiconductor - gallium arsenide laser
4. Liquid - Inorganic dye laser

11. TYPES OF LASER CONTD.

12. PATTERNS OF LASER OUTPUT
• The configuration of the resonator cavity and the method in which an energy source is applied to the
‘active laser medium’ will determine the pattern of a laser output.
• The output may be continuous wave or pulsed.
• A continuous wave laser operates with a constant intensity.
• A laser that operates with a continuous output for longer than 0.1 seconds is considered a
continuous wave laser.
• A pulsed laser produces a single or train of pulses with each individual pulse less than 0.1 seconds.
• A Q-switch is an electrooptical component that facilitates the production of a very short (less than 1
microsecond) but high intensity pulse of laser energy.

13. BASIC LASER TISSUE INTERACTION
• Photoablative reactions : molecular bonds are divided.
The ruby laser, for example, can split the molecular bonds of tattoo ink with
minimal local thermal damage. Macrophages remove the tattoo ink after the
molecular bonds are broken.
• Photochemical reactions: infrared, visible or ultraviolet laser light interacts with
photosensitizers to produce chemical and physical reactions. This forms the basis
for photodynamic therapy.

14. • Photomechanical effect : laser energy is pulsed to disrupt tissue or stones by the
mechanism of shock waves.
An example of this mechanism would be the use of the Holmium YAG laser to
shatter ureteric and renal calculi.
• Photothermal reaction: conversion of absorbed laser light into heat. cutting,
coagulation or vaporization depending on the laser wavelength and the laser
delivery device.
The photothermal mechanism is predominant in laser use in otolaryngology and
examples include CO2 microlaryngoscopy and the argon laser for stapedotomy.

15. • The effects of laser on tissue rely on one of the following interactions: absorption, scattering,
transmission, or reflection.
• The type of interaction between a laser beam and any tissue is determined by the wavelength of
the laser beam, the operation mode of the laser, the amount of energy applied, and tissue
characteristics.
• “the shorter the wavelength, the greater the effect on the tissue.”
• Shorter the wave length, more scattering, more the adjacent tissue damage.

16. • Lasers whose wavelengths are within 0.1–0.8 μm (UV and visible region of the
spectrum) cause minimal water absorption but considerable hemoglobin-melanin
absorption.
• Lasers with a wavelength >3 μm absorb water. The visible lasers penetrate into tissue
at approximately 1 mm.
• The Nd:YAG laser goes into tissue at 4 mm and absorbs minimal water.
• The penetration depth of the CO 2 laser is only 30 μm, which makes it superb as a
cutting tool.

17. CHANGES IN TISSUE EXPOSED TO A LASER
• Related to the temperature created by the laser.
• Cutting with a laser is narrow controlled vaporization!
• In temperatures higher than 50°C, enzymatic activity decreases.
• Protein denaturation occurs at temperatures over 60°C.
• Over 80°C, the collagen degrades.
• At 100°C water vaporizes, which results in expansion of the steam and finally
tissue ablation.
• Although providing perfect hemostasis, a laser incision causes a delay in wound
healing.
• Collateral thermal damage, although inevitable, can be minimized by using
infrared lasers. Lasers can be used for incision, vaporization, or coagulation.

19. LASER LIGHT DELIVERY DEVICES
• Suited specifically for the wavelength that they transmit.
• Examples of delivery systems would be an articulated arm, a mirror lens system,
micromanipulator, fibre optic fibre, shaped tip fibre optic fibres and robotized scanners.
• An articulated arm uses a system of hollow tubes and mirrors to direct the laser beam to the
target area.

20. LASER LIGHT DELIVERY DEVICES CONTD.
• Micromanipulators and other focusing devices can be connected to microscopes.
Micromanipulators and focusing devices will create an accurate and reproducible
spot on target tissue.

21. LASER LIGHT DELIVERY DEVICES CONTD.
• The bare fibre optic fibre is the most common technique for delivering laser
energy to tissue. The flexibility and diameter of fibre optic fibre facilitates their
use with both rigid and flexible endoscopes.
• Changing the distance between the fibre and the tissue can produce all the tissue
photothermal effects of coagulation, incision and vaporization. A fibre ‘in
contact’ with tissue will create an incision.
• The cut is similar to a saw rather than a knife.

22. LASER LIGHT DELIVERY DEVICES CONTD.
• A shaped tip laser is a laser fibre with a tip constructed of another material, such
as metal or synthetic sapphire. The laser energy heats the tip and it is the
conduction of heat from the tip that produces the tissue interaction.
• Eg: sapphire tipped neodynium YAG fibre used to ablate tracheobronchial
tumours.

23. COMMONLY USED LASERS
•CO 2 Laser :wavelength is 10,600 nm, which is not visible. Its power is between 0.1
and 100 W. Practically, its energy is absorbed by the tissue within a 0.2-mm depth. Any tissue
with a high water content selectively absorbs the CO 2 laser.
• For an incision, a small spot size with a high power density is preferred.
• New CO 2 laser systems have a spot size as small as 160 μm.
• For vaporization purpose, a low power density is applied with a large spot size. This also
creates a heat energy that coagulates blood and lymph vessels. However, its hemostasis
capability is limited to vessels

24. • Argon Laser: The argon laser is typically used for the coagulation of
hemangiomas.
• Emits a green-blue light, visible in the range of the electromagnetic
spectrum (458–515 nm), and has a penetration depth of 1 mm.
• Because of its wavelength, it is almost completely absorbed by
hemoglobin, melanin, and myoglobin.

25. • Nd:YAG :solid-state laser that delivers a 1060-nm beam (near
infrared).
• The penetration depth is 3–5 mm because of its low absorption by
water and tissue pigments. This low absorption also causes
scattering and reflection.
• Therefore, its use for coagulation purposes requires high power,
making the thermal coagulation of vessels and hemangiomas
possible.
• Tracheobronchial lesions, particularly for its excellent hemostatic
qualities; nonablative skin resurfacing; and hair removal in ethnic
patient populations.

26. • KTP-532 Laser (potassium titanyl phosphate): Works by passing an
Nd:YAG laser through a KTP crystal, resulting in the emission of half
its wavelength (532 nm), which becomes visible.
• The delivery system is a fiberoptic carrier (for vaporizing and
coagulation effects) or a contact quartz tip (for cutting).
• Since this laser is primarily absorbed by oxyhemoglobin, it is mainly
used in the treatment of vascular lesions (including superficial skin
lesions and telangiectasias) and the surgical reduction of turbinate
tissue.

27. • Erbium:YAG Laser :emits a 29–40 W, which is highly absorbed by
water (12–18 times more efficiently than CO 2 laser).
• The erbium:YAG laser has the disadvantage of poor hemostatic
qualities and limited collagen tightening compared with the CO 2
laser.
• It is primarily used for superficial skin resurfacing for fine
wrinkles, brown spots, and acne scars.

28. INDICATIONS OF LASER
Ear Surgery
CO2 laser, KTP laser, Argon laser
 Stapedotomy (making a fenestra in the footplate of stapes)
 laser stapedotomy minus prosthesis (STAMP)
 Myringotomy
 Mastoid surgery
 Excision of vesibular shwannoma

29. INDICATIONS OF LASER CONTD.
Nasal and sinus surgery
Holmium YAG laser, KTP laser, Nd YAG laser, Argon laser
 Excision of inverted papilloma
 Debulking of large malignant tumors
 Total excision of small malignant tumors
 Shaving off rhinophyma
 Choanal atresia surgery

30. Nasal and sinus surgery (contd.)
 Telangectasia destruction
 Septal spur resection
 Antrostomy creation
 Turbinate reduction
 Endonasal dacrocystorhinostomy
CO2 laser ‘swiftlase’ (oscillating device)
 Excision/reduction of nasal polyp
 Turbinate reduction

31. ORAL CAVITY
• CO2 laser, Diode laser
 Leukoplakia
 Erythroplakia
 Haemangioma

32. ORAL CAVITY (CONTD.)
• CO2 laser, Diode laser
 Papilloma
 Oral submucous fibrosis
 Carcinoma tongue
 Carcinoma buccal mucosa
 Debulking of large/recurrent inoperable tumors

33. •Laser-Assisted Uvulopalatoplasty-C02 laser
•Laser tonsillectomy-C02 Laser
•Laser laser excision gingival hyperplasias, pyogenic
granulomas, and papillomas -C02 laser
•For especially vascular lesions, photocoagulation with an
Nd:YAG laser is preferred

34. PHARYNX AND LARYNX
• CO2 laser
 Laryngeal papilloma
 Laryngeal web
 Subglottic stenosis
 Haemangioma
 Vocal nodule / polyp
 Leukoplakia of vocal cords

35. PHARYNX AND LARYNX (CONTD.)
• CO2 laser
 Reinke’s edema
 Arytenoidectomy
 Early malignant lesions of the vocal cord (partial cordectomy)
 Partial laryngectomy

36. TRACHEA AND BRONCHI
• CO2 laser
 Recurrent respiratory papillomatosis
 Tracheal stenosis
 Granulation tissue in the trachea

37. VOCAL CORD PARALYSIS
• Posterior cordotomy, Medial arytenoidectomy, and Total arytenoidectomy.
• In a posterior cordotomy, laser can be used to incise the vocal cord anterior to
the vocal process. The anterior vocal process is then excised or vaporized
unilaterally or bilaterally.
• In a medial arytenoidectomy, the vocal process and the medial portion of the
arytenoid body are vaporized, preserving the lateral arytenoid body and the
aryepiglottic fold.
• A total arytenoidectomy can also be performed with the CO 2 , KTP-532, and
Nd:YAG lasers.

38. TRACHEA AND BRONCHI (CONTD.)
• Nd YAG laser combined with CO2 laser
 Early tracheal tumors
 Endobronchial tumors
 Debulking of obstructive malignant lesions of trachea or bronchi

39. ADVANTAGE OF LASER
Advantage of lasers over conventional surgery
• Precision of surgery
• Excellent tissue coagulation (better hemostasis / less bleeding)
• Less postoperative edema and pain
• Minimal thermal effect on adjacent tissues
• Minimal postoperative scarring
• Faster postoperative recovery

40. DISADVANTAGE OF LASER
 High cost in the purchase of equipment and its maintenance
 Fire hazard
 Special anaesthesia requirements of avoid fires
 Explosion

41. LASER SAFETY
Principles of safety:
• A laser beam may hit or damage objects outside the target
area and cause a fire, tissue damage or eye/visual damage
 The patient should be shielded by
• wet gauze or fireproof material from
• accidental strikes
• (the patient’s eyes can be protected by saline-soaked
eye pads)

42. LASER SAFETY CONTD.
The anaesthetic tube and airway should be protected from accidental strikes that could produce a
fire .
• Protection of standard tracheal tubes - Protection with wet swabs
Reflective wrapping of tracheal tubes
Protection of the tracheal tube cuff
Factory-wrapped tracheal tubes
Silicone rubber tubes with metallic protection
Metal cuffed tubes

43. LASER SAFETY CONTD.
• All personnel in the operating room should wear correct eye protection
appropriate to the wavelength of the laser.

44. LASER SAFETY CONTD.
Principles of safety:
• Warning sign plus locked doors should prevent unprotected and unprepared individuals from
walking into the operating room when the laser is in use.
• Key to switch on the laser should be held by a senior member of the operating team to ensure
only properly qualified individuals use the laser.
• Operating room and windows should be laser protected.
• Endoscopic equipment should be blackened to reduce accidental reflective strikes of the laser.

45. REFERENCES
• Scott brown 8th edition
• Current diagnosis and treatment in otolaryngology and
head,neck surgery 3ed
• Cummings otolaryngology head and neck surgery 5th ed

46. THANK YOU