1. Tympanoplasty, Mastoidectomy, Facial Nerve Decompression
Hau Sin Wong
Grand Rounds
10/27/04

2. Tympanoplasty
Definition: operation involving tympanic membrane and evaluation of middle ear
Whereas myringoplasty is an operation of the tympanic membrane
Tympanoplasty can be accompanied with or without mastoidectomy

3. Types of Tympanoplasty
Type I: restoration of normal ME with intact ossicles
Type II: Ossicular chain partially destroyed but preserved ad continuity restored

4. Type III: TM lays on stapes suprastructure
Type IV: Round window protection with a small middle ear mobile footplate left exposed
Type V: Closed middle ear with round window protection; fenestra in the horizontal semicircular canal coveredby a skin graft.

5. Middle Ear Anatomy Ossicles: Malleus, Incus, Stapes
Ligaments: sup malleolar ligament, stapedial tendon
Cochlearform process, pyramidal process

8. Technique Evaluate TM and ME if perforation present
Create vascular strip
Incise postauricular incision for mastoidectomy
Mastoidectomy- identify lateral landmarks for drilling. Anterior boundary-post EAC, superior boundary- root of the zygoma, linea temporalis, inferior boundary- mastoid tip. Drill medially and saucerize, delineating Tegmen superiorly, thinning post EAC anteriorly, Sigmoid sinus posteriorly, Horizontal SCC medially
Identify vertical segment of facial nerve between HSCC and digastric ridge
Open facial recess: boundaries are fossa incudus, facial nerve, chorda tympani
Visualization of incus, malleus in antrum, incus and stapes in facial recess.

9. Tympanomeatal flap
EAC skin and TM elevated anteriorly

13. TM grafts:
1. Cartilage 2. fool’s fascia (loose areolar fascia over temporalis fascia) 3. temporalis fascia
Medial or lateral graft placement

14. Facial Nerve Decompression

15. Anatomy 5 segments Meatal- brainstem to IAC
Labyrinthine- fundus of IAC to facial hiatus (includes fallopian canal-narrowest segment of facial canal)
Tympanic- geniculate gangilion to pyraminal eminence
Mastoid-pyramidal eminence to stylomastoid foramen
Extratemporal- stylomastoid foramen to muscles of facial expression ( temporal, zygomatic, buccal, mandibular, cervical)

16. Anatomy Arterial Supply:
Intracranial segment supplied by labyrinthine artery off the AICA
Tympanic segment supplied by superficial petrosal artery off the middle meningeal artery
Mastoid segment supplied by the stylomastoid artery off the external carotid artery

19. Facial Nerve Decompression
Eggshell the facial canal (vertical segment)
Open Facial recess and extended the facial recess using a barber pole method
Follow facial nerve to the tympanic segment
Eggshell covering overlying facial nerved removed, exposing the sheath
Sheath incised and facial nerve decompressed.