This document discusses two cases of petrous bone cholesteatoma. It provides background on petrous bone anatomy and classifications of petrous bone cholesteatoma. It also describes the surgical approaches and considerations for treatment of petrous bone cholesteatoma, which aim to completely remove the disease while preserving vital structures like the facial nerve. Two cases of petrous bone cholesteatoma are presented and the surgical treatments used in each case.

1. PETROUS
CHOLESTEA
TOMA
DR ANUSREE A KARUN
PETROUS BONE CHOLESTEATOMA
Dr Anusree A Karun

2. PETROUS BONE CHOLESTEATOMA
Uncommon pathologic
condition(4-6% of all temporal
bone lesions)used to define an
epidermoid cyst of the petrous
portion of the temporal bone
A surgical challenge
considering the complex
anatomic relationship with vital
intracranial structures and the
risk of csf leak .
Two cases of petrous bone
cholesteatoma are entailed here.

3. CASE REPORT
CASE1
A 49 yr old male pt
came with H/O left ear
discharge-since 10yrs
H/O head ache-4
months
Patient also had left
facial palsy hard of
hearing & following
previous surgery for
cholesteatoma
k/c/o DM,HTN-1yr on
treatment
CASE 2
24 yr old male
presented with chief
complaints of
Left sided headache
-4mnths
And Giddiness *3
mnths
No h/o any
comorbidities

4. PAST HISTORY
CASE1
Pt underwent modified
radical mastoidectomy in
2014 (for extensive
cholesteatoma)
Radical mastoidectomy in
2015(for recurrent
cholesteatoma )
Craniotomies twice for
extradural abscess and
zygoma excision for
zygomatic abscess in 2016
CASE2
H/O MRM 8 yrsback

5. GENERAL PHYSICAL EXAMINATION
General examination:
Pt GC fair
Afebrile
Nopallor/icterus/cyanosis/lymphadenopathy/clubbing/pedal edema
CVS-s1,s2+
RS-B/L AE+
P/A-soft,no organomegaly
CNS-NFND

6. ENT EXAMINATION
PTA Right –wnl
Left- severe mixed HL
Right-wnl
Left-mild CHL
CASE1 CASE2
EXTERNAL EAR
Preauricular region normal normal
Pinna normal normal
Post auricular region Left-Scar + Right -normal Left- Scar+ Right-normal
EAC Left-Blind sac closure
Right –normal
Left-Normal
Right-normal
TM Left-Not seen Right-normal Left-normal Right-neotympanum
Fistula sign absent absent
3 point/tragal tenderness absent absent
TFT Rinne
Weber
ABC
+ve -ve
Lateralised to LEFT
Not reduced
+ve -ve
Lateralised to LEFT
Not reduced
Facial nerve Grade 5 facial palsy normal
Vestibular signs absent absent

7. CASE1- HRCT-craniotomy
defect + large cystic
destructive lesion noted in
left EAC,ME
cavity,squamous,temporal,m
astoid and PETROUS
portion and facial canal
F/s/o ? recurrent
cholesteatoma –with petrous
bone involvement
CASE2 HRCT-soft tissue
opacity note in the left
mastoid and extending into
petrous temporal bone
Middle ear appears
normal,with intact ossicles

8. CASE 2-MRI-clearly demonstrates
the extension of cholesteatoma
into petrous apex with intact ME
inner ear structures
CASE1-MRI-post radical
mastoidectomy status-soft tissue
density noted in mastoid and
middle ear extending to petrous
apex,fallopian canal involvement+
RAMASAMY 49/M
Temporal
2017 01 05
16 38 pm
BIR 3372
R
R L
TR 3760
TE 89.00
‘KK_15/150
TR 3760
TE 89.00
SP F33 5
SL 5 0/5 44
FeV 186 4s
‘KK_15/150
SP F33 5
SL 5 0/5 44
FeV 186 4s

9. DECISION
CASE1 – diagnosed as massive petrous bone cholesteatoma
pt taken up for trans cochlear approach(pt already had
grade 5 facial nerve palsy and non serviceable hearing on
left )
Case2 –provisionally diagnosed as infralabyrinthine petrous
bone cholesteatoma taken up for subtotal petrosectomty
in view of hearing preservation
MASSIVE INFRALABYRINTHINE

10. SURGERY VIDEO

11. PETROUS BONE-RELEVANT
ANATOMY
Petrous bone :That part
of the temporal bone
medial to the middle ear
cleft.
Consists of base ,apex,
anterior ,inferior and
posterior surfaces
Shaped like a pyramid,
contains the semicircular
canals, vestibule,
cochlea, and carotid
artery.

12. PETROUS APEX
Petrous apex : That part of
the temporal bone medial
to the otic capsule,
between the greater wing
of sphenoid and occiput
The superior surface is formed by the
middle cranial fossa, Meckel cave& ICA
Along inferior surface is jugular bulb and
IPS

13. IAC bisects the petrous
apex into a large anterior
portion that typically
contain bone marrow and
a smaller posterior
portion derived from otic
capsule
The petrous carotid
canal and IAC are the
largest channels
traversing the petrous
apex
The Dorello canal,
subarcuate canal,
singular canal, and
Meckel cave are smaller
channels.

14. PBC-CLASSIFICATION
According to Sanna et al. [1993] PBCs can be classified into
five groups:
 supralabyrinthine-geniculate ganglion
 infralabyrinthine-hypotympanic and infralabyrinthine cells
infralabyrinthine-apical-infralabyrinthine compartment
extending to petrous apex
Massive-otic capsule
Apical-petrous apex
These terms describe both the location and the extent of the
lesion.

15. ROUTES OF SPREAD
Extension of acquired cholesteatoma into petrous occurs
in large cholesteatoma and in well pneumatized petrous
bone
In medial extension ,cholesteatoma follows course of least
resistance & erodes thin wall of petrous air cells
1.Infralabyrinthine-below cochlea & IAC,may break into
jugular fossa
2.Anterosuperior-above cochlea,involving geniculate
ganglion&extending into supra meatal area of petrous bone
3.Posterosuperior-between limbs of Superior SCC to
reach fundus of IAC

16. 1.Subaarcuate
via arch of scc-FRECKNER
2.Retrolabyrinthine
Superior to lscc & posterior to superior
scc-THORNWALDT
3.Infralabyrinthine(hearing preserving)
inferior to posterior scc
posterior to VII nerve and superior to
jugular bulb[DEARMIN &FARRIOR]
4.Subcochlear/infracochlear-(hearing
preserving)hypotympanic air cell tract
between ica,jugular bulb and
cochlea[FARRIOR]
5/6.peritubal–
b/w ica,cochlea and tegmen
5-Ramdier/lempert
6-Kopetsky/Almoor
7.Middle cranial fossa (hearing
preserving) EAGLETON

17. TREATMENT PROTOCOL
Main factors to be considered are
(1) complete eradication of the disease
(2) preservation of facial nerve function,
(3) prevention of CSF leak and meningitis,
(4) Cavity obliteration
(5) hearing preservation whenever feasible

18.  If the patient presents with preserved hearing, four routes are possible:
1.transcanal infracochlear,
2.Transsphenoidal
3. Infralabyrinthine- but limited access, especially in patients with high
jugular bulb
4.middle cranial fossa- but it does not allow a permanent drainage pathway,
and some degree of temporal lobe retraction is necessary, which could
result in brain injury
 If hearing is not preserved, there are two more options:
1.translabyrinthine
2. transcochlear
 Trans otic approach preserves facial nerve

19. TREATMENT PROTOCOL
SUPRALABYRINTHINE
Hearing normal sensory neural HL or
No e/o fistula in cochlea e/o fistula in cochlea
Middle fossa approach with subtotal petrosectomy/
Transmastoid approach enlarged translabyrinthine /
transotic approach with
cavity obliteration

20. Infralabyrinthine infralabyrinthine apical
(hearing preservation isnt possible)
N Hearing SNHL VII N normal VII N palsy
Subtotal transotic transotic/ IFTB+ modified
petrosectomy IFTB Transcochlear approach A

21. Massive Apical & those with extn to clivus,nasopharyn
Hearing preservation not possible & sphenoid sinus
VII N nrml VII N palsy
hearing N SNHL SNHL+VII palsy
VII n nrml VII palsy
Transotic MTCA
IFTB IFTB+TO IFTB+MTCA

22. CONCLUSION
• With thorough pretreatment evaluation of location and extent of lesion ,
meticulous radiological assessment, planning and execution, the difficult
terrain of petrous apex can be approached and dealt with successful
results
• Unlike any other lesion of the petrous apex ,cholesteatoma has the
advantage of total removal and disease clearance in the hands of an
experienced surgeon with meticuluos dissection ,by simply foolowing the
lesion
• Classification is important to decide the appropriate surgical approach.
• The facial nerve requires special consideration as it gets involved in
almost all the cases and is a cornerstone of management.
• Radical removal takes priority over hearing preservation even in only
hearing ears with the possibility of hearing rehabilitation (CI, BAHA and
Soundbridge).
• Regular follow-up is mandatory