5. Anatomy
• The normal
conducting apparatus
of the middle ear
consists of an intact
tympanic membrane
and three ossicles
connected in series.
• Any disruption of
these components
can cause conductive
hearing deficits.
15. The tensor tympani
Supply by Trigeminal
nerve
Tendon leaves the bony
wall via the
cochleariform process
16. The stapedius
Supply by fascial nerve
Tendon leaves the bony wall via the apex of the pyramidal
eminence
17. Ligaments of the ossicular chain
• How many
ligaments?
• Superior malleal
ligament
• Anterior malleal
ligament
• Lateral malleal
ligament
• Posterior incudal
ligament
• Superior incudal
ligament
19. Physiology:
• The acoustic resistance to the passage of
sound through a medium is termed impedance.
• couples(change)the sound (Air) low impedance
Electrical signals (fluid) high
impedance
• The true gain of the middle ear is 35 dB
• Middle ear couples sound signals from the
ear canal to the cochlea primarily through the
action of
1. Tympanic membrane
2. ossicles
20. Catenary lever
Through attachment of Tympanic
membrane to the annuls
hydraulic lever
Through the tympanic
membrane
ossicular lever
Through the ossicles
21. Catenary Lever
• The attachment of the tympanic membrane at
the annulus amplifies the energy at the malleus
because of the elastic properties of the stretched
drumhead fibers.
• Because the annular bone surrounding the
tympanic membrane is immobile, sound energy
is directed away from the edges of the drum and
toward the center of the drum.
• The malleus receives the redirected sound
energy from the edge of the drum because of
the central location of the manubrium.
22. Hydraulic Lever
• The hydraulic lever acts because of the size difference
between the tympanic membrane and the stapes
footplate. The average ratio has been calculated to be
20.8:1
• Sound pressure collected over the tympanic membrane
and transmitted to the area of the smaller footplate
results in an increase in force proportional to the ratio of
the areas
• TM=55mm,Stapes=3.2mm
23. Ossicular Lever
• The malleus and incus acting as a unit, rotate around an
axis running between the anterior mallear ligament and
the incudal ligament.
• The gain of the ossicular lever is the length of the
manubrium of the malleus divided by the length of the
long process of the incus (approximately 1.3:1).
26. Etiology
• Fixation
– Malleus head ankylosis (idiopathic)
– Ossicular tympanosclerosis
– Scar bands in chronic otitis media
• Discontinuity
– Trauma
– Erosion by chronic otitis media/
cholesteatoma (most common)
• Eroded incudostapedial joint (80% of
patients)
• Absent incus
• Absent incus and stapes superstructure
27. Contraindications
• Acute infection of the ear is the only true
contraindication.
• Why??Acute infection will most likely
result in poor healing, prosthesis
extrusion, or both.
• Relative contraindications include
persistent middle ear mucosal disease,
tympanic membrane perforation, and
repeated unsuccessful use of the same or
similar prostheses.
28. Preoperative Assessment:
• The goal of ossicular chain reconstruction is
better hearing, most typically for conversational
speech.
• Bringing the operative ear to within 15 dB of the
contralateral ear will enhance binaural input to
auditory centers; A patient's perceived hearing
improvement is best when the hearing level of
the poorer-hearing ear is raised to a level close
to that of the better-hearing ear.
• In patients with severe mixed hearing loss,
ossicular reconstruction can be considered,
because it may enhance the use of
amplification.
30. Plan for surgery
• By which Materials?
• Staging of operation?
• Which approach?
• Which techniques?
31. 1st Q By which?
• Autologus graft:
Tissue transplant form one part of body to
another of the same individual.
1. Bone(incus,cortical bone)
2. cartilage
32. By which
• Homologus graft:
Tissue transplant from one person to another.
1. Incus bone
2. Cartilage
Incus
One week
2months
in 70%
ethanol
33. By which
• Alloplastic materials:
Different types
(plastipore,ceramics,hydroxyapatite,titanu
m)
Have good functional hearing but extrusion
rate remain high(2-4%)
PORP
TORP
35. 2nd Q Staging?
1st stage: done during the first surgery
• Normal of minimally hypertrophied ME
mucosa
• Patent ET orifice
• Mobile stapes foot plate
2nd stage: done after 6months to 1 year form
surgery:
• Residual cholesteatomea left
• Obstruction of ET orifice by polypoidal
mucosa or tympanoseclerosis
36. 3rd Q Which Approach?
A. Transcanal:
ossiculoplasty via transcanal ,with appropriate
canaloplasty done in 1st stage.
• No postauricular incision
• 2nd stage operation
• close tympanoplasy(intact call wall)
37. Which Approach?
B. Transcanal-Transmastoid- :
ossiculoplasty carried out through post
tympanotomy and transcanal if 2nd stage
operation is not planned
• Postauricular incision
• 1st stage
• close tympanoplasty (intact call wall)
38. Which Approach?
C. Transmastoid :
performed through the mastoid and post-
tympanotomy with out disturbing the skin of EAM
and position of new TM .
• Post-auricular incision(same incision)
• 2nd stage
• close tympanoplasty (intact canal wall)
39. Which Approach?
D. Trans-meatal:
Performed through the ear speculum which
you did appropriate meatoplasty in 1st
stage
• No postauricular incision
• 2nd stage
• Open tympanoplasty(canal-wall down)
40. Which Approach?
E. Retroauricular-trans canal:
• Postauricular incision
• 1st stage
• No mastoid surgery only Ossiculoplasty
1. Traumatic dissociation of ossicle
2. Same stage of TM reconstruction and
normal ME .
42. Which technique?
Definition:
operation to eradicate disease in ME and
reconstruct the hearing mechanism without
masoid surgery with/without TM grafting
• Wullstein Tympanoplasty (1956)
– Type I
– Type II
– Type III
– Type IV
– Type V
45. Types of tympanoplasty
Type III—
intact mobile stapes
superstructure
– TM onto capitulum of
stapes
– Absent mallus and
incus
46. Types of tympanoplasty
Type IV—
intact stapes footplate with
absent or eroded stapes
superstructure
– TM onto footplate
– Footplate MOBILE
– TM covers RW
47. Types of tympanoplasty
• Type V:
Graft placed over
fenestration of foot
plate
Immobile
footplate
48. Which technique?
• Austin classification:
Uses Middle ear ossicular status (Incus
necrosis)
Type A:M+S+ (between SS and MallusTM
reconsturion )
Type B:M-S+ (between SS and neoTM)
Type C:M+S- (between SF and MallusTM
reconsturion )
Type D:M-S- (between SF and neoTM)
55. 1st scenario
•Left ear. A large
epitympanic erosion is
seen
with epidermization of
the attic and posterior
mesotympanum.
•The cholesteatoma,
visible in transparency,
causes
bulging of the tympanic
membrane in the
posterior
inferiorquadrants.
• Resorption of the incus
and head of the malleus
56. Plan for surgery
• By which Materials?
• Staging of operation?
• Which approach?
• Which techniques?
57. 2nd Scenario
•Right ear. Tympanosclerosis with
perforation.
•The tympanosclerotic process
involves the anterior residues of
the tympanic membrane and the
mucosa of the promontory
reaching to the posterior
mesotympanum
•The long process of the incus is
eroded.
•Stapes fixed
58. Plan for surgery
• By which Materials?
• Staging of operation?
• Which approach?
• Which techniques?
59. 3rd scenario
•Left ear. Perforation of the
posterior quadrantsof the
tympanic membrane.
•The skin advances along the
posterosuperior border of the
perforation towards the
incudostapedial Joint.
• A tympanosderotic plaque.
•Long process of incus erosion
,mallus present
60. Plan for surgery
• By which Materials?
• Staging of operation?
• Which approach?
• Which techniques?
