2. โข Light Amplification by Stimulated Emission of
Radiation
โข Quantum Theory โ interaction of light & matter
3. โข 4 lasers FDA approved
โข Visible spectrum
1. Argon laser (514nm)
2. Potassium titanyl phosphate KTP (532nm)
โข Infra red spectrum
1. Carbon dioxide CO2 (10600nm)
2. Erbium yttrium aluminium garnet YAG
(2960nm)
4. โข Laser stapedotomy and laser revision stapedectomy
โข 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. โข Mechanical stapedotomy do not
produce a round symmetrical
stapedotomy
โข 81% failure of stapes surgery โ
prosthesis migrated out of oval
window fenestration onto solid fixed
stapes footplate.
6. โข Few hits of pulsed co2 laser beam focussed to a 0.6 mm spot
size
โข 0.6 mm Fisch trocar used to freshen the margins โ
PRECISION โ eliminates collagen seal
โข Improved stapedotomy prosthesis โ should measure 0.25 mm
longer- resists displacement out of stapedotomy during
valsalva
โข Post op contracture can lift prosthesis โ commonest
complication
โข 3 indications for seal
1.Perilymph gusher
2.Footplate fracture or mobilization
3.Stapedotomy too large for prosthesis
7. โข Has a profound advantage
โข Ant tympanotomy
โข Determine margins & depth of the
oval window
โข Any residual stapes footplate
โข Relationship of prosthesis to the
vestibule
8. โข Vaporize the collagen neomembrane โ
until margin of oval window precisely
identified
โข 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. โข Incus eroded lippy moon Robinson offset prosthesis
โข Incus too short โ Leinski malleus to oval window
prosthesis โ titanium aerial prosthesis -sterile allograft
collagen membrane placed between TM and prosthesis
10. โข Haemostasis โ inaccessible to bipolar cautery
โข Meticulously vaporize unwanted soft tissue โ less
damage to inner ear- exposure to infection is reduced
โข Oval window obliterated by cholesteatoma, granulation
tissue, hyperplastic mucosa and adhesions.
11. โข Acoustic neuroma, glomus tumours, skull base tumour
โข Epidermoid carcinoma off adventia of carotid artery
โข Benign tumours off a dehiscent facial nerve
12. โข EM energy of lasers
โข Emission spectroscopy โ cancer cell specific great
degree of accuracy
โข Inner ear endoscopy and spectroscopy โ cannulate the
ear with tiny optical fibres and perform emission
spectroscopy at various sites in vestibular and cochlear
partitions.
