Lasers in otology

LASERS IN ENT

1. Dr. Ajay Manickam
MS ENT PGT
R.G. Kar Medical college & Hospital

2. •Light Amplification by Stimulated Emission of
Radiation
•Quantum Theory – interaction of light & matter

3. •4 lasers FDA approved
•Visible spectrum
1.Argon laser (514nm)
2.Potassium titanyl phosphate KTP (532nm)
•Infra red spectrum
1.Carbon dioxide CO2 (10600nm)
2.Erbium yttrium aluminium garnet YAG
(2960nm)

4. •Laser stapedotomy and laser revision stapedectomy
•4 Requirements
1.Precise optics
2.Efficient absorption by bone & collagen
3.Minimal heating of perilymph
4.No damage to inner ear or facial nerve structures from
photons transmitted through perilymph

5. •Mechanical stapedotomy do not
produce a round symmetrical
stapedotomy
•81% failure of stapes surgery –
prosthesis migrated out of oval
window fenestration onto solid fixed
stapes footplate.

6. •Few hits of pulsed co2 laser beam focussed to a 0.6 mm spot
size
•0.6 mm Fisch trocar used to freshen the margins –
PRECISION – eliminates collagen seal
•Improved stapedotomy prosthesis – should measure 0.25 mm
longer- resists displacement out of stapedotomy during
valsalva
•Post op contracture can lift prosthesis – commonest
complication
•3 indications for seal
1.Perilymph gusher
2.Footplate fracture or mobilization
3.Stapedotomy too large for prosthesis

7. •Has a profound advantage
•Ant tympanotomy
•Determine margins & depth of the
oval window
•Any residual stapes footplate
•Relationship of prosthesis to the
vestibule

8. •Vaporize the collagen neomembrane –
until margin of oval window precisely
identified
•Tissue surrounding prosthesis is
vaporized
1.Identify residual stapes footplate
2.To determine exact length required for
new footplate
3.Stabilize new prosthesis in the centre of
oval window

9. •Incus eroded lippy moon Robinson offset prosthesis
•Incus too short – Leinski malleus to oval window
prosthesis – titanium aerial prosthesis -sterile allograft
collagen membrane placed between TM and prosthesis

10. •Haemostasis – inaccessible to bipolar cautery
•Meticulously vaporize unwanted soft tissue – less
damage to inner ear- exposure to infection is reduced
•Oval window obliterated by cholesteatoma, granulation
tissue, hyperplastic mucosa and adhesions.

11. •Acoustic neuroma, glomus tumours, skull base tumour
•Epidermoid carcinoma off adventia of carotid artery
•Benign tumours off a dehiscent facial nerve

12. •EM energy of lasers
•Emission spectroscopy – cancer cell specific great
degree of accuracy
•Inner ear endoscopy and spectroscopy – cannulate the
ear with tiny optical fibres and perform emission
spectroscopy at various sites in vestibular and cochlear
partitions.