Download Slide 1 - EPS 2013

Tympanoplasty,
Mastoidectomy, Facial
Nerve Decompression
Hau Sin Wong
Grand Rounds
10/27/04
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
Types of Tympanoplasty
Type I: restoration of
normal ME with intact
ossicles
Type II: Ossicular
chain partially
destroyed but
preserved ad
continuity restored
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.
Middle Ear Anatomy
Ossicles: Malleus, Incus, Stapes
Ligaments: sup malleolar ligament,
stapedial tendon
Cochlearform process, pyramidal process
Technique
1.
2.
3.
4.
5.
6.
7.
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.
Tympanomeatal flap
EAC skin and TM
elevated anteriorly
TM grafts:
1. Cartilage 2. fool’s
fascia (loose areolar
fascia over temporalis
fascia) 3. temporalis
fascia
Medial or lateral graft
placement
Facial Nerve
Decompression
Anatomy
5 segments
1. Meatal- brainstem to IAC
2. Labyrinthine- fundus of IAC to facial hiatus
(includes fallopian canal-narrowest segment of
facial canal)
3. Tympanic- geniculate gangilion to pyraminal
eminence
4. Mastoid-pyramidal eminence to stylomastoid
foramen
5. Extratemporal- stylomastoid foramen to muscles
of facial expression ( temporal, zygomatic,
buccal, mandibular, cervical)
Anatomy
Arterial Supply:
1. Intracranial segment supplied by
labyrinthine artery off the AICA
2. Tympanic segment supplied by
superficial petrosal artery off the middle
meningeal artery
3. Mastoid segment supplied by the
stylomastoid artery off the external
carotid artery
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.