2. Laser in ENT

3. L ight A mplification by S timulated E mission of R adiation

4.  *Invented in 1958 by Charles Townes & Arthur Schawlow, based on Einstien’s idea of ((particle-wave duality)) of light,30 years earlier.  *Originally called MASER…microwaves

5. Laser Fundamentals 1.Monochromatic:one color / wavelength. 2.Highly directional: narrow beam in a specific direction. 3.Coherent: one phase in space & time. Deposit a lot of energy within small area.

6. Components 1.Active medium: a. solid….ruby,Nd:YAG b. liquid dyes. c. gases..CO2,Helium/Neon d. semiconductors..GaAs 2.Excitation mechanism: electrical,chemical or optical 3.Optical resonator: high& partial reflection mirrors.

7.  Laser Delivery Systems  1.Hollow waveguide or tube.  2.Glass fiber optic cable.

12. LASERs used in ENT 1. CO2 Laser: A continuous wave of 10600 nm which is absorbed by water and soft tissues. It has high precision and sequentially removes layers of cells.

13. Advantages of CO2 laser: 1.Bloodless dissection: The laser beam can seal blood vessels up to 0.5 mm in diameter. 2.Immediate tissue destruction by instantaneous vaporization 3.Minimal instrumentation required to deliver the laser beam 4.Minimal damage to adjacent tissue with minimal post-operative oedema.

14. 2. Argon Laser: Produced by Argon gas with blue green visible light of 488-514 nm. It has high photo coagulation power There can be moderate surrounding tissue damage

15. 3. KTP – 532: (Crystal of potassium titanyl phosphate) Produce by a blue-green visible light of 532 nm Does not require an aiming beam Absorption high in vascular tissue Moderate surrounding tissue damage

16. 4. Nd: YAG: Crystal rod of Yttrium aluminium garnet with neodymium ions. Produces infrared light of 1064 nm Requires an aiming beam Absorption good in vascular tissue Moderate surrounding tissue damage

17. 5.Diode Laser This a lightweight, portable, battery supported,810-980-nm wavelength Diode laser with a fiber optic delivery system is being used widely the field of otolaryngology, as it is less expensive.

18. ENT indications CO2 laser is most commonly used in ENT. Larynx: Done with microlaryngoscopy for Juvenile laryngeal papillomas Laryngeal web Vocal nodules Capillary haemangioma T1 carcinoma of mobile vocal cords Arytenoidectomy Subglottic stenosis

19. Oral cavity: Debulking of large inoperable tumours Tonsillectomy in cases of blood dyscrasias Superficial lesions Palatal surgeries like UPPP Nose: Inverted papilloma, Haemangioma Nasal polyps Turbinectomy Nasal tumours. This is combined with sinoscopy

20. Tracheobronchial tree: Respiratory papillomatosis Tracheal stenosis Granulation tissue Bronchial adenoma Ear: Myringotomy Stapedectomy Acoustic neuroma

21. Complications of Laser Ocular Injuries: Infrared light produced by laser can cause corneal and retinal injury. Hence, protective glasses must worn by surgeon, staff and anaesthetist Cutaneous injuries: Direct and reflected laser energy can cause skin burns to the patient and others in the operation theatre

22. Surrounding structures like trachea, oral cavity and vocal cords Anaesthetic complications Damage to endotracheal tube can lead to fire from direct or reflected laser beam. Hence the endotracheal tube is coated with an aluminium foil and proper selection of the anaesthesia gases is made.