Various types and Surgical steps of Mastoidectomy.

1. MASTOIDECTOMY
- DR. DHIRENDRA V. PATIL
M.S. (ENT)
J.N.M.C., Aligarh Muslim University

2. HISTORY
 The first scholarly treatise on mastoid surgery
for suppurative disease was by ‘Schwartze’ in
1873.
 The procedure he described was a ‘cortical
mastoidectomy’ with limited exenteration of
mastoid air cells.
 In1890, Zaufal described removing the superior
and posterior canal wall, tympanic membrane,
and lateral ossicular chain, a procedure now
known as the ‘radical mastoidectomy’.

3.  This procedure was modified by Bondy, who
recognized that disease limited to the pars
flaccida could simply be exteriorized, leaving
the uninvolved middle ear alone. His
description of the “modified radical
mastoidectomy” or “Bondy procedure” in 1910
represented one of the first reports addressing
hearing function.

4.  Interest in hearing preservation and
restoration gained further attention after
Lempert introduced the fenestration operation
in 1938, and Zollner and Wullstein
described tympanoplasty techniques in
early1950s.
 Lempert popularized the use of a drill and
loupe magnification in the 1920s.

5.  During the next decade, Jansen, Sheehy,
and others extended these principles of
restoring function and maintaining normal
anatomy with the introduction of the intact
canal wall mastoidectomy with facial recess
approach.
 With the advent of CWU mastoidectomy,
disease control as well as preservation of
anatomy and function became a reality.

6.  The first postauricular incision was
introduced in 1853 by Sir Willium Wilde
of Dublin.

7. INTRODUCTION
 Descriptions of chronic and suppurative
infections of the mastoid have been discovered
dating back to ancient Greece.
 Prior to the advent of surgery and antibiotics,
morbidity from acute mastoiditis was
considerable.
 Mastoid surgery has evolved from simple
trephination for acute infection, to the
canalwall preserving mastoidectomy employed
by inost otologists today.

8.  Chronic otitis media, with or without
cholesteatoma, is one of the more common
indications for performing a mastoidectomy.
 Mastoidectomy permits access to remove
cholesteatoma matrix or diseased air cells in
chronic otitis media.

9.  CWU mastoidectomy is used as a standard
approach for
1. Cochlear implantation,
2. Excision of tumors, and
3. Surgery for vertigo.
However, the primary role of CWU
mastoidectomy is in the control of chronic otitis
media, with and without cholesteatoma.

10. CLASSIFICATIONS
 Traditionally, classified as :
1. Simple (cortical, complete) mastoidectomy
2. Modified radical mastoidectomy
3. Radical mastoidectomy
 A fourth procedure, Tympanomastoidectomy ,
combines the simple mastoidectomy with a
middle-ear procedure, maintaining the posterior
and superior canal walls.

11.  Depending on the fact whether
postero-superior canal is removed or not,
 1. Canal Wall Up mastoidectomy
 2. Canal Wall Down mastoidectomy.

12. SUBCLASSIFICATION (M.Tos)
CANAL WALL UP (CWU) CANAL WALL DOWN (CWD)
1. Simple/ cortical/ complete/
Schwartze’s mastoidectomy
1. Atticotomy
2. Classic Intact Canal Wall
Mastoidectomy/ Combined
Approach Tympanoplasty (CAT)
2. Atticoantrotomy
3. Radical Mastoidectomy
4. Modified Radical
Mastoidectomy/ bondy’s
Procedure
5. Retrograde Mastoidectomy

13.  Depending upon the mastoid cavity,
 1. Open Technique
 2. Closed Technique

14. CLASSIFICATION IN RELATION TO REMOVAL OF
THE BONY EAR CANAL WALL AND OBLITERATION
OF CAVITY

15. ANATOMICAL
CONSIDERATIONS

16.  The temporal bone consists of four parts:
squamous, tympanic, mastoid, and petrous
(Figs.)
 Important surface landmarks on the mastoid
include the temporal line, which extends
posteriorly from the zygomatic root and is the
insertion site for the temporalis muscle.

19.  The suprameatal spine of Henle is a small
bony protuberance extending superficially from
the posterior and superior bony EAC.
 Posterior to the suprameatal spine, a group of
small holes is seen, described as the
cribriform area.
 Small vessels pass through these foramina to
the mucosa of the underlying antrum in infants,
and it’s here that a subperiosteal abscess
forms in cases of acute coalescent mastoiditis.

20.  This cribriform area lies within Macewen’s
triangle, an imaginary triangle defined by
three lines-
 1. Temporal line
 2. Line formed by the superior and posterior
margins of the external bony meatus (This line
goes through the suprameatal spine)
 3. Line drawn perpendiular to the first line and
tangential to the second.

23.  Mastoid antrum lies around 1.25 cm to 1.5 cm
deep from the surface of Macewen’s triangle.
 Cymba concha is the soft tissue anatomical
landmark for the mastoid antrum.

25.  Facial Bridge is that portion of
posterosuperior bony meatal wall that bridges
over the notch of Rivinus and overlies the
ossicles.
 Facial Ridge is that part of the bony meatal
wall which houses the posterior bend and
vertical segment of facial nerve.
 Anterior Buttress is the point at which the
posterior bony canal wall meets the tegmen.

26. DIAGRAM TO SHOW FACIAL RIDGE, BRIDGE,
ANTERIOR AND POSTERIOR BUTTRES

27.  Posterior buttress marks the meeting of the
posterior canal wall and the floor of the EAC
lateral to the facial nerve.
 Its removal causes the floor of EAC to slope off
gently into the mastoid tip.

31.  Citelli’s angle (Sinodural angle)- is an angle
between the sigmoid sinus and middle fossa
dural plate.
 Solid angle is an area where three bony
semicircular canals meet.
 Trautmann’s triangle is bounded by bony
labyrinth (solid angle) anteriorly, sigmoid sinus
posteriorly and dura superiorly.

32.  Donaldson’s line is a line passing through
the horizontal semicircular canal and bisects
the posterior semicircular canal.
 This line is a landmark for the
endolymphatic sac.

35. DEFINITIONS

36. APPROACHES And
ROUTES
 The term ‘Approach’ means the method of
access to the middle ear through the soft
tissues.
 eg. Endaural approach, Retroauricular
approach.
 The term ‘Route’ means the method of access
to the middle ear through the bone.
 eg. Transcortical route, Transmeatal Route.

38. CORTICAL
MASTOIDECTOMY
 CORTICAL MASTOIDECTOMY (Schwartze 1873)
is a transcortical opening of the mastoid cells
and the antrum.
 It is the initial stage of any transmastoid
surgery of the
1)middle ear 2)inner ear, 3) facial nerve,
4)endolymphatic sac, 5) labyrinth, 6) I.A.C and
7) skull base.

41.  SIMPLE MASTOIDECTOMY – This term is
usually used when mastoidectomy is done for
drainage of a mastoid abscess.

42. COMBINED APPROACH TYMPANOPLASTY
(CAT)/ CLASSIC INTACT CANAL WALL
MASTOIDECTOMY
 CAT consists of a large mastoidectomy with an
intact but thin bony ear canal wall and a
posterior atticotympanotomy.
 The intact canal wall technique is performed in
two stages.
 The first operation is performed to remove all
cholesteatoma and repair the tympanic
membrane.

43.  Six months later, the second operation is
performed to inspect the mastoid and middle
ear for residual or recurrent cholesteatoma and
to improve hearing by ossicular reconstruction.

44. STEPS OF CAT
1. Cortical mastoidectomy
2. Anterior Tympanotomy : via tympanomeatal
flap
3. Posterior Tympanotomy: via facial recess
approach
4. Tympanoplasty

48. DEFINITIONS
 ATTICOTOMY (EPITYMPANOTOMY)- denotes
opening of the attic, performed through the
transmeatal route.

50.  ATTICOANTROTOMY- is an extension of the
atticotomy in a posterior direction through the
transmeatal route, in which lateral attic and
aditus walls are removed, and the antrum is
entered.
 It can be performed through the transcortical
route, but is usually performed through a
transmeatal route.

52.  BONDY’S OPERATION – An atticoantrotomy is
called as Bondy’s operation if the tympanic
cavity is not entered.
 The lateral part of the cholesteatoma is
removed (fig) and the medial part is left in
place (fig), marsupialising the cholesteatoma.
 If the tympanic cavity is entered, it is NOT
described as BONDY’S operation but as an
atticoantrotomy or conservative radical
operation.

55. MODIFIED RADICAL
MASTOIDECTOMY
 Classically, modified radical mastoidectomy
refers to the Bondy procedure, in which disease
limited to the epitympanum is simply
exteriorized by removing portions of the
adjacent superior or posterior canal wall.
 But, Frequently, the term modified radical
mastoidectomy is used interchangeably with
canal wall down mastoidectomy.

56.  A primary feature of the modified radical
procedure is complete removal of the posterior
canal wall, the major reason for failure of the
Bondy procedure.
 MRM is an effective method to manage
cholesteatoma in a ‘single-stage’ approach
(Unlike CAT).

57.  MRM is a surgical procedure where the disease
process is eradicated from the middle ear cleft;
followed by converting the mastoid cavity,
middle ear and EAC into a single, smooth, self-
cleansing cavity exteriorised through EAC.

59. RADICAL
MASTOIDECTOMY
 Radical mastoidectomy is a canal wall down
mastoidectomy performed to eradicate disease
from middle ear cleft in which mastoid cavity,
tympanum and EAC are converted into a
common cavity exteriorised through the EAC,
wherein the structures of tympanic cavity
(remnants of the incus and malleus, and the
drum remnant) are removed.

60.  In ‘Classical Radical Cavity’, closure of the
eustachian tube is performed.
 But, closure of the eustachian tube is NOT
essential for the term ‘Classical Radical
Operation’.

62. INDICATIONS

63. INDICATIONS OF CORTICAL
MASTOIDECTOMY
1) Coalescent Mastoiditis and Masked Mastoiditis.
2) CSOM TTD Active Refractory to antibiotics.
3) Secretory otitis media Refractory to antibiotics.
4) Approach to:
-Endolymphatic sac surgery.
-Facial nerve decompression.
-Vestibulo cochlear nerve section.
-Translabyrinthine Approach for CP angle.
-Cochlear implant surgery.
-Combined Approach Tympanoplasty.

64. Indications For MRM
 Absolute Indications (Shambaugh):
1. Unresectable disease
2. Unreconstructable Posterior canal wall
3. Failure of first stage CWU procedure because
of poor E T function.
4. Inadequate Patient Follow up.

65.  Relative Indications (Shambaugh):
1. Disease in only hearing ear or in a dead ear.
2. Medical illness
3. Severe otologic or CNS complications
4. Neoplasms
5. Poor E T function.

66. CONTRAINDICATIONS
1. Chronic otitis media without cholesteatoma
2. Acute otitis media with coalescent mastoiditis,
3. persistent secretory otitis media, or
4. Chronic allergic otitis media.
5. Tuberculous otitis media.

67. Indications For Radical
Mastoidectomy (shambaugh)
 1. Unresectable cholesteatoma extending down
the Eustachian tube or into the petrous apex
 2. Promontory cochlear fistula caused by
cholesteatoma
 3. Chronic perilabyrinthine osteitis or
cholesteatoma that cannot be removed and
must be cleaned or inspected periodically
 4. Resection of temporal bone neoplasms with
periodic monitoring

68. CWU Vs CWD
 The choice for preserving or removing the
posterior wall of the EAC, ie, CWU versus CWD
mastoidectomy, has been extensively debated.
 Preservation of the canal wall is preferred.
 The decision to remove the wall is most often
made during surgery, when the extent of the
disease is fully appreciated.

69.  Intraoperative findings that may be indications
for a CWD procedure include
-labyrinthine fistula,
-unresectable disease on the facial nerve or
stapes footplate,
-a low-lying tegmen that limits access to the
attic,
-unresectable sinus tympani disease,
-and an unreconstructable posterior canal wall
defect.

70.  Removal of the canal wall does not
improve access to the sinus tympani.
 Rarely, our preoperative evaluation may
result in the decision to take down the
canal wall.
 1.Obvious posterior wall erosion,
 2.larger labyrinthine fistula on CT scan,
 3.elderly or infirmed patients in which
second look is unadvisable.

71.  4. Occasionally with disease in an only hearing
ear, are preoperative conditions that may
warrant a CWD procedure.

73. OPERATIVE
TECHNIQUES(CWU)
Preparation-
 General anesthesia without paralytic agents
and with continuous facial nerve Monitoring.
 Tragus and postauricular skin are injected with
1% lidocaine with epinephrine (1: 100,000) to
provide hemostasis and local anesthesia.
 “Pre-scrub" the ear and the entire side of the
head, including hair, with betadine.

74. The surgical site is
then prepped and draped in sterile fashion.

75. INCISION
 The postauricular incision is made
from helical rim to mastoid tip,
approximately 1 cm posterior to the
sulcus.
 Care is taken to avoid making the
incision in the sulcus as this can make
closure more difficult.

77.  A T-shaped incision is made in the mastoid
periosteum to expose the mastoid cortex
 An incision is made along the linea temporalis,
to the level of the underlying bone.
 A second periosteal incision is made
perpendicular to the linea temporalis and is
carried down to the mastoid tip.

78.  .

79.  Using the Lempert elevator, the
periosteum is elevated superiorly
over the tegmen, posteriorly over
the sigmoid sinus, and anteriorly
to the level of the EAC meatus.

81. Two self-retaining retractors
are used perpendicular to each other to
expose the entire
mastoid and EAC

82. Middle Ear Dissection
 Some authors (shambaugh) prefer to begin
with middle ear dissection prior to
mastoidectomy to control middle ear disease
and ascertain the state of the ossicular chain.
 Ossicular erosion may allow for removal of the
incus and malleus to protect the stapes and
footplate from injury prior to dissection of the
attic.

83.  The tympanomeatal flap is elevated anteriorly
and is carefully dissected free from the
ossicular chain.
 Cholesteatoma, if present, is gently dissected
from the middle ear to expose the ossicles and
facial nerve.

84.  Cholesteatoma or granulation tissue is
dissected free from the ossicles, leaving the
ossicular chain intact if possible.
 If preservation of the ossicular chain is not
possible, separation of the incudostapedial joint
is performed early to prevent injury to the
stapes or inner ear.

85. Canalplasty
 Often middle ear dissection and postoperative
follow-up is facilitated by canalplasty, which is
performed at the onset of the procedure.
 Using a 2-mm diamond burr, excess tympanic
bone at the tympanomastoid and
tympanosquamous suture lines is removed.
 Often removal of this small amount of bone
greatly improves the exposure, ensuring better
disease resection and graft placement.

86.  Extreme care must be taken when drilling in
postrior-inferior quadrant of the canal as this is
the area of the canal where the facial nerve is
at most risk to injury.
 A canalplasty should always be done first as
it defines the anterior limit of your
mastoidectomy .

87. Completed canalplasty with
entire annulus visible

88. Mastoidectomy
BASICS:
 Mastoidectomy is conducted with the
visualization afforded by the
1. Binocular-operating microscope
2. High-speed drill, and
3. Suction-irrigation.

90.  a) cutting bur b)cutting diamond bur (note the
course texture) c) a diamond bur.

91.  Cutting burrs are efficient at removing large
amounts of bone in a small amount of time.
 Diamond burrs are very good at delicate
dissection around important structures,
thinning the bone off the sigmoid sinus,
tegmen, facial nerve, and opening the facial
recess.
 During the mastoidectomy, larger burrs are
used first and the burr size is sequentially
decreased as the areas of dissection get
narrower.

92.  The largest burr possible should always be
used as it is less likely to inadvertently
penetrate an underlying structure and is yet
more efficient for bone removal.
 The surgeon must always be aware of what
the back of the burr may be touching.

93. Drilling tips
 Avoid keyhole surgery; work through a wide
space
 The tip of the drill should always be visible
 Never drill behind edges of bone
 Drilling should always be parallel to any
structure you are trying to preserve e.g.
facial nerve, sigmoid sinus
 When drilling deeper in the mastoid cavity the
burr needs to be lengthened

94.  One cannot lengthen a cutting burr as this
will cause the drill to jump with the risk of
injuring structures

95.  Therefore if it is necessary to lengthen the
burr, then change to a rough diamond or
diamond burr.

96.  Effective use of the suction irrigator is
important for safe and effective drilling.
 Appropriate irrigation is necessary
1. to clear bone dust from the field of dissection,
2. to prevent excessive heat transfer to
underlying structures (especially the facial
nerve), and
3. to maintain a clean cutting surface on the bur.

97. Canal-Wall-Up
Mastoidectomy
 Initial dissection involves using a 5- or 6-mm
cutting burr and removing bone along the linea
temporalis to identify the underlying tegmen.

98.  The surgeon should look for the emergence of
a pink hue under the bone as it is thinned
over the tegmen, accompanied by a change
(more "tinny") in the sound of the burr.
 Once located, the surface of the tegmen is
followed medially toward the antrum.
 The middle fossa dura is always delineated as it
is the superior extent of the dissection.

99.  After identification of the tegmen, cortical bone
is removed behind the EAC, keeping the
posterior wall of the EAC thin, but intact.
 A key landmark in performing mastoid surgery
is the antrum with the dome of the horizontal
semicircular canal (HSCC) along its floor. The
ease of locating the antrum depends largely on
the degree of mastoid pneumatization.

100.  Three key principles assist this part of the
dissection:
 1.saucerization,
 2.identification of the tegmen plate, and
 3.thinning the posterior canal wall.

101.  The deepest dissection is at the point where
the initial cortical bone cuts intersect, but
widely saucerizing toward the tegmen and
especially posteriorly (from the sinodural angle
to the mastoid tip) as the antrum is approached
is essential.
 As the bone over the sigmoid sinus is thinned,
a bluish hue will become apparent beneath
the bone, accompanied by a change in the
sound of the burr.

102.  With the tegmen, sigmoid sinus, and posterior
canal wall identified, the antrum can now be
dissected, following the tegmen anteriorly.
 Koerner's septum, the embryologic remnant of
the fusion plane between the petrous and the
squamous bones is often encountered next.
After penetrating Koerner's septum, the antrum
is uncovered and the surgeon can identify the
lateral semicircular canal.

104.  In patients with CSOM, the antrum may be
observed with cholesteatoma, granulation
tissue, or edematous mucosa, obscuring the
lateral semicircular canal and making its
identification more difficult.

105.  The next step is attic dissection, which is
performed by following the tegmen anteriorly
and by thinning the canal wall posteriorly and
superiorly.
 Care is taken to avoid drilling a hole in the
bony canal wall.
 Rotating the operating bed toward the surgeon
affords simultameous viewing of the canal and
the mastoid.

106.  Drilling out the zygomatic root and opening
the attic is often better accomplished with a 3-
mm cutting burr and a smaller suction irrigator.
 The tegmen is carefully followed and usually
dips inferiorly as the epitympanum is
approached from posterior to anterior.

107.  The attic air cells are opened completely, fully
exposing any epitympanic disease.
 Granulation and cholesteatoma can now be
removed from the canal or attic vantage points.
 The cog is a flat, thin, bony projection from
the tegmen, in the parasagittal plane, that
appears to have a semicircle cut out of the
inferior border. (Cog: bony ridge hanging from
tegmen tympani lies 1 mm above & posterior to
cochleariform process.)

108.  Located directly superior to the cochleariform
process, with the tensor tympani tendon it
creates a small, roughly round aperture that
opens into the anterior epitympanum.
 If it is not specifically identified and removed,
significant disease may be left in the anterior
attic.
 Preserving facial nerve function is paramount
in ear surgery.

109.  Except for simple mastoidectomy, it is always
safer to define the location of facial nerve than
simply to avoid it.
 In intact canal wall mastoidectomy (or when a
cochlear implant is placed), the space between
the facial nerve and the chorda tympani
nerve—the facial recess—provides access into
the middle ear (Fig.)

112.  In canal wall down approaches, identifying the
facial nerve allows the surgeon to lower the
facial ridge appropriately, creating a more care-
free cavity.

113.  The most important landmarks for the facial
nerve are the
1. HSCC,
2. The short process of the incus,
3. The posterior bony external auditory canal
4. The digastric ridge.
The genu and proximal portion of the mastoid
segment of the facial nerve lie anterior and just
medial to the dome of the HSCC.

114.  The mastoid segment of the facial nerve also
lies medial to the plane of the short process of
the incus at the base of the posterior canal
wall.
 Removing air cells from the posterior bony
canal wall until it is only a few millimeters thick
is essential.

115.  If the canal wall is not thinned appropriately, a
wall of air cells continues to cover the facial
nerve, and the dissection is carried too far
posteriorly, potentially exposing the posterior
side of the facial nerve to injury.
 After locating the antrum, a diamond bur is
used to open the aditus ad antrum, which leads
into the epitympanic space.

117.  The short process of the incus is exposed. With
this landmark visible, a larger cutting bur or
coarse diamond bur removes bone over the
area of the facial nerve, with continued
thinning of the posterior bony canal wall as the
dissection is carried medially.
 When the plane of the short process of the
incus is reached, it is anticipated that the facial
nerve will be 1 to 2 mm deeper, and the bur
type is changed to a fine diamond

118.  Strokes are made in a longitudinal direction,
paralleling the course of the facial nerve.
 Dehiscences of the mastoid portion of the
fallopian canal, even in the presence of mastoid
disease, are infrequent.
 This is in contradistinction to the tympanic
segment of the facial nerve, where congenital
and disease-mediated dehiscences are
common.

119.  Appropriately thinning the canal wall often
exposes the chorda tympani nerve, which can
be distinguished from the facial nerve by size
and course of direction.
 If disease is limited to the antrum,its not
needed to uncover the vertical segment of the
facial nerve to determine its location.

120. Opening the Facial Recess
 The facial recess is a triangular-shaped area
bordered by the facial nerve posteriorly, the
incus buttress superiorly, and chorda tympani
nerve anterolaterally (Figure).
 Access to the mesotympanum can be gained by
removing the bone in the facial recess.

122.  For additional exposure, the facial
recess can be extended inferiorly by
sacrificing the chorda tympani nerve
 The entire mesotympanum and
hypotympanum can usually be
accessed through the mastoid by the
extended facial recess approach
(figure).

124.  In chronic ear surgery, the long
process of the incus has been eroded,
and that ossicle is removed.
 In such cases, the fossa incudis is
taken down, connecting the facial
recess with the aditus ad antrum,
providing wide exposure over the
HSCC and the genu of the facial
nerve into the epitympanum (Fig).

126. Opening the Epitympanum
 In intact canal wall mastoid surgery, it is
frequently necessary to expose the
epitympanum.
 Cholesteatoma can track medially to the heads
of the ossicles and extend into the anterior
epitympanic space, also termed the supratubal
recess. Opening the epitympanum is much
easier if there is discontinuity of the ossicular
chain (e.g., eroded long process of the incus).

127.  In such cases, the incus remnant and
the head of the malleus are removed,
providing good access into the
anterior aspect of the epitympanum.
 It is important to appreciate the
anatomic relationships of the facial
nerve within the epitympanic space.

128.  As the nerve is traced anteriorly from
the mastoid genu to the geniculate
ganglion, it takes a slightly medial
course. It passes superior to the oval
window and cochleariform process
(Fig.).

130.  The facial nerve in the floor of the
anterior epitympanic space can be
dehiscent, especially if extensive
cholesteatoma involves this region
(Fig.).

132. Dissection of
Cholesteatoma
 Before dissecting the cholesteatoma sac from
the mastoid bone, the sac should be opened
and its contents should be evacuated, leaving
the matrix in place.
 The consistency of cholesteatoma matrix is
quite variable, ranging from a relatively thick
and well defined capsule to loose squamous
debris without any visible capsule.

133. CLOSURE
 Upon complete removal of disease, the ear
canal and mastoid cavity are irrigated
extensively with antibiotic-containing saline
solution to remove any bone dust and
remaining squamous debris.
 The self-retaining retractors are removed and
the vascular strip skin flap is unfurled and
placed back into the ear canal.
 The postauricular incision is closed in two
layers.

134.  The incision is covered in antibiotic ointment
and a Glasscock ear dressing (Otomed) is
applied.

135. Canal Wall Down
Mastoidectomy

136.  Many of the disadvantages of a canal wall
down procedure can be minimized with proper
creation of the mastoid cavity.
 Crucial components of the procedure include
the following:
 1.Aggressively saucerizing the cavity
 2.Eliminating irregularities within the cavity
(e.g., deep recess and bony overhangs)
 3.Removing the posterior bony canal wall to
the level of the facial nerve

137.  4.Creating a large meatus.
 Saucerization decreases the depth
and the size of the mastoid cavity.
 The cortical edges of the cavity are
taken down to the approximate level
of the tegmen superiorly, sigmoid
sinus posteriorly, and digastric ridge
inferiorly (Fig.).

139.  All mastoid air cells should be removed with
exposure of the middle fossa and posterior
fossa dural plates, the sigmoid sinus, digastric
ridge, and bony canal wall (Figure 31-lE).

140.  Cholesteatoma and granulations filling
the central mastoid tract can be
removed at this time.
 The vertical segment of the facial
nerve should now be identified,
followed by opening of the facial
recess (Figure 31-lF).

142.  The posterior canal wall can now be safely
taken down with a rongeur and the facial ridge
can be lowered until a thin layer of bone
remains over the vertical segment of the facial
nerve (Figure 31-IG)

144.  The inferior canal wall must be drilled
away until the inferior canal wall and
mastoid tip are confluent, with no
bony overhang to obscure the
mastoid tip.
 The sinus tympani is the most difficult
region to investigate. If disease
extends into this region, and if the
stapes is absent, the pyramidal

145.  eminence can be removed with a
small diamond bur.
 At this point, the cavity should be
smooth-walled and free of active
disease (Figure 31-lH).

147.  Meatoplasty:
 One percent lidocaine with 1:100,000
epinephrine is infiltrated into the
conchal bowl.
 With a finger in the conchal bowl, a
semilunar incision is made into the
cartilage posteriorly until the knife tip
is felt through the anterior skin.

148.  This crescent-shaped cartilage
measures about 1.5 x 2 cm (Figure
31-1j).

152. COMPLICATIONS
 Trauma to Dura
 Horizontal Semicircular Fistula
 Trauma to Facial Nerve
 Sigmoid Sinus and Jugular Bulb Injury.

153. TRAUMA TO DURA
 A dural tear or significant abrasion with
herniation of arachnoid tissue with or without a
cerebrospinal fluid leak requires REPAIR.
 Best repaired with a layered closure using soft
tissue such as fascia or perichondrium
combined with a more rigid support material
such as bone or cartilage.
 Broad-spectrum antibiotics.

154.  Firmly packing the mastoid (or
epitympanum) with absorbable
gelatin sponge (Gelfoam) (with or
without fibrin glue) can be used to
support the repair.

155. Horizontal Semicircular
Fistula
 Should always be considered when performing
chronic ear surgery
 A flattened HSCC dome suggests labyrinthine
erosion.
 In such cases, the cholesteatoma sac is
opened, the desquamated epithelium is
removed, and the matrix is left intact over the
canal.

156.  If an actual erosion into the fluid space of the
HSCC is encountered or suspected during
palpation, the cholesteatoma matrix should be
left in place.
 When all other disease is removed, several
options are possible:
1) remove all matrix, and cover the defect with
soft tissue or bone wax;
2) perform a canal wall down procedure, and
allow the matrix to remain in place as part of
the mastoid cavity; or

157. Or
3) perform an intact canal wall procedure
and leave the matrix in place to be
removed at a second stage when the ear
is sterile.
-Broad-spectrum antibiotic and steroids
should be considered if the canal has
been entered.

158.  Iatrogenic injury to the HSCC requires
immediate closure- bone wax/soft tissue.

159. INJURY TO FACIAL
NERVE
 Identification, rather than avoidance, of this
structure is fundamental for Mastoidectomy
procedure.

162. Sigmoid Sinus and Jugular
Bulb Injury
 Sigmoid sinus and jugular bulb are
characterized by variable anatomy.
 This fact places these structures at risk for
inadvertent injury.
 Injury to these low-pressure, but high-volume,
venous structures is initially treated with digital
pressure.
 For small tears-bone wax.
 For larger rents-cellulose-type surgical packing.

163. Thank you
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