Download Cerebellopontine Angle Tumors: Diagnosis and Management

Andrew Coughlin, MD
Faculty Advisor: Tomoko Makishima, MD, PhD
The University of Texas Medical Branch
Department of Otolaryngology
Grand Rounds Presentation
September 30, 2010
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History of CPA tumors
Discuss Relevant Anatomy
Epidemiology and Tumor Biology
Signs/Symptoms of CPA tumors
Brief overview of other CPA tumors
Treatment options
Present a case presentation
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Represent 10% of all intracranial tumors
Vestibular Schwannomas/Acoustic Neuroma
represent 78% of these tumors (1)
Differential
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Meningiomas
Epidermoids
Other Cranial Nerve Schwannomas
Dermoid Tumors ( Chordomas, Teratomas)
Arachnoid Cysts
Lipomas
Metastatic Tumors
Vascular Tumors (Hemangioma/Glomus Tumor)
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Sir Charles Balance (2,3)
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1894 First successful removal of Vestibular
Schwannoma
1907 Patient still alive but had CN VII paresis
Harvey Cushing
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1917 Monograph described CPA syndrome
Pioneered subtotal resection through bilateral
suboccipital craniectomy
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Walter Dandy (5)
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Advocated debulking with capsule removal and
decreased operative mortality to 10%
William House (6-8)
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Advocated Translabyrinthine approach 1960’s
Introduced the microscope and dental drill to
identify the facial nerve
Introduced middle cranial fossa approach
Ipsilateral
Hearing Loss
Facial
Hypesthesia
Hydrocephalus
Respiratory
Failure and
Death
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Autopsy series have shown incidence of 1.7 to
2.7% (9,10)
MRI of 10,000 patients seen for non-otologic
reasons showed 7 positive cases or 0.07% (11)
Denmark reports of 1.3 per 100,000 population
(12)
1.
They are not Neuromas
2.
They rarely are found on the acoustic portion of
the nerve
*Involvement of the acoustic portion of the nerve
often leads to erosion of the cochlea.
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Arise from Schwann cells within the IAC (1)
Equal frequency between inferior and superior
divisions of the vestibular nerve.
Arise from Scarpa Ganglion instead of
Obersteiner-Redlich zone.
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Scarpa’s ganglion has highest density of schwann
cells
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NF 2 Gene found at 22q12
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Sporadic Variety (95%) (13)
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Tumor suppressor gene preventing schwann cell
proliferation
Hypothesized that there are two hits to the normal
NF gene
Neurofibromatosis type II
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Autosomal Dominant
Inherit one abnormal and one normal gene with one
hit to the normal allele.
Blood tests available to screen family members.
1.
Neuregulin
Expressed by schwann cells to control proliferation
and survival of schwann cells
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2.
Chemokines
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3.
FGF, TGF-β, VEGF, PDGF (14-17)
Sex Hormones (18)
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Previous studies showed increased growth in
pregnancy
Recent studies have not shown growth modulation
or receptors for sex hormones
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History and Physical Exam
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Audiologic testing
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Vestibular Testing
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Imaging
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Intracanalicular tumors
1.
2.
3.

CPA extension
1.
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Hearing Loss
Tinnitus
Vestibular dysfunction/Vertigo
Disequilibrium/Ataxia
Brainstem Extension
1.
2.
3.
Midface Hypesthesia
Hydrocephalus (vision loss and headache)
Other Cranial Neuropathies
*SNHL>tinnitus>disequilibrium>facial hypesthesia
(13)
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Present in >85% of patients (19)
5% of patients with VS have no associated
hearing loss (20)
Speech discrimination out of proportion to HL

Many notice difficulty on the telephone
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Occurs in up to 20% of patients (13)
1% of patients with SSNHL have a vestibular
schwannoma (21)
48% of patients with SSNHL will have some
recovery of hearing (21)
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Don’t rule out VS if they recover
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2nd most common presenting sign
Often precedes hearing loss
Can be present without hearing loss
Can be high pitch, hissing, or a roar
Can localize to the opposite ear
Unilateral tinnitus should be evaluated
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36-50% of patients describe disequilibrium (1)
Vague, transient lightheadedness
Acute vertigo is presenting symptom in 27% of
patients but is associated with smaller tumors.
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Presenting symptom in 4% of patients
Larger tumors >2cm
Maxillary division 1st
Corneal reflex is the first to go
Facial weakness is rare
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If present should assume a different type of tumor.
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Rare
Loss of corneal reflex
Nystagmus (toward affected side)
Diplopia
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Involvement of CN VI
Blurry vision
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Papilledema and optic atrophy from compression
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Hitselberger Sign
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Decreased sensation of EAC
Sensory VII more sensitive than Motor VII
Absent corneal reflex, nystagmus
Hypesthesia to pinprick and touch
Weakness of Temporalis/Masseter muscles
Other cranial neuropathy’s
Gait disturbances or difficulty with finger to
nose testing
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Downsloping high frequency SNHL 65% (22)
5% of patients show no hearing loss (23)
Rollover: Speech discrimination worse than
expected and worse with increased sound
intensities
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Retrocochlear losses more common than cochlear
AAO-HNS classification
Class
Pure tone average (0.5, 1, Speech discrimination
2, 3 kHz measured in dB score (%)
HL)
A
0–30
70–100
B
31–50
50–100
C
>50
50–100
D
Any
<50
Gardner-Robertson Classification
Class
Pure Tone/Speech
Speech Discrimination
Reception Threshold (dB Score (%)
HL)
1
0–30
70–100
2
31–50
50–69
3
51–90
5–49
4
>90
1–4
Word Recognition Scores
Class
Word Recognition Score (%)
I
70–100
II
50–69
III
1–50
IV
0%
**Positive test has 85% sensitivity for identifying
retrocochlear problem
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Acoustic Reflex Threshold
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Increased (compared with cochlear norms) or absent
if retrocochlear process
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Sensitivity of 85 to 90% (25)
False Positive rate 10%
False Negative rate 18-30% for intracanalicular
tumors
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Number larger than in the past
Five waveforms are produced with the most
common being a latency in wave V compared
to the normal ear of >0.2msec.
Recommended as a screening test for those
with low suspicion of vestibular schwannoma.
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70-90% of patients will show some abnormality
(26)
50% of small tumors produce no abnormalities
(27)
Caloric testing is commonly the only
abnormality
Inferior vestibular nerve tumors may be missed
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Superior nerve showed decrease in 98%
Inferior nerve shows decrease in only 60% (28)
Therefore not used as a screening test
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90% of vestibular schwannomas will enhance
with contrast
Frequently misses tumors that are not
intracanalicular and do not extend >5mm to
the CPA.
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63% accuracy at diagnosis (29)
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Gold Standard for Vestibular Schwannomas
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Gadolinium is preferentially taken up by tumor
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Hyperintense on T1 and T2 studies
Non-contrasted studies
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Better visualization of small tumors
Gadolinium enhanced studies
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Can identify tumors as small as 3mm (30)
Hypointense T1, Isointense on T2
Some recommend T2 fast spin-echo MRI as
screening test but most will likely require at thin
slice MRI if abnormalities are found (31)
VESTIBULAR
SCHWANNOMA
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Centered on IAC
Globular appearance
Ice cream cone
appearance in IAC
Bony erosion of IAC
Cystic degeneration or
hemorrhage may be
present
MENINGIOMA
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Extend along petrous
ridge
Sessile appearance
“Dural Tail” at
periphery
Iso/Hypointense on T1
Hypo to Hyperintense
on T2
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3% of all CPA tumors (13)
Do not metastasize but do recur due to bony
invasion
Are formed from cap cells around arachnoid
villi near dural sinus’ and where CN’s enter
their foramina
Generally are not intracanalicular so must be
larger to cause hearing concerns
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Signs and Symptoms (32)
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Usually cause spontaneous nystagmus, facial
hypesthesia, and gait ataxia
If inferior can cause hoarseness, dysphagia, tongue
atrophy
If within the IAC can produce similar symptoms as
Vestibular Schwannoma
Hearing tests will show retrocochlear process if
large enough, and 25% will have normal ABR’s
(33)
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Treatment

Surgical Excision
 Must remove rim of normal dura and possibly bone

Poor hearing
 Translabyrinthine approach

Good hearing
 Suboccipital or Middle Fossa Approach
 Middle Fossa is better for more superiorly based
tumors.
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Identical to cholesteatoma
Develop from epithelial rest cells
Slow growing
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Commonly don’t present until 20-30’s
Arise adjacent to brainstem and infiltrate areas
of least resistance
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Can have irregular shape and infiltrate widely
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Signs/Symptoms
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Facial twitching is commonly described
Can become quite large before causing symptoms
Progressive facial paralysis more common than
schwannomas
Audio/ABR/Speech discrimination consistent
with other retrocochlear losses
Treatment is surgical excision
T1 post
Gadolinium
T1 post
Gadolinium
T2
T1
Flair
T1
T2
T1
T1
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Histologically identical to Vestibular
Schwannomas
Characteristics
Rarely restricted to IAC
 Commonly have skip lesions
 Generally involve part of geniculate ganglion
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Signs/Symptoms
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Unilateral hearing loss
Tinnitus
Vertigo
Aural fullness (if distal to geniculate)
Facial weakness is rare unless very large
Hearing tests show retrocochlear process but
impedance testing can show ipsilateral absent
acoustic reflex
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Treatment is observation
If growth or facial nerve dysfunction
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Resection of nerve with cable grafting
Translabyrinthine approach most commonly used
Facial nerve decompression can be used if
paresis is developing
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Glomus Tumors
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Hemangiomas
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Bright on T1 and T2, Drained via infralabyrinthine approach
Embryonic tumors (Dermoids, teratomas, chordomas)
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Treatment is drainage
Cholesterol Granulomas
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Centered on geniculate, slow progressive facial weakness,
surgical excision with facial nerve grafting
Arachnoid Cysts
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Jugular Foramen Syndrome (IX,X,XI), Surgical excision
Excision with dysfunction
Primary Axial Tumors of CNS (glioma,
hemangioblastoma, medulloblastoma)
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Surgical excision +/- radiation therapy
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Observation
Surgery
Stereotactic Radiosurgery
Radiation Therapy
**Generally tumors <3cm can be treated with
stereotactic radiosurgery but microsurgery is the
treatment of choice
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Growth rates vary from 0 to 2cm per year with an
average of 2mm (34)
38.9-82% have some growth at ≥38 months (24)
14 to 24% of patients watched will go on to have some
treatment (12)
Age should not be determining factor
1.
2.
3.
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Single MRI is not adequate
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Young patient with small tumor
Older patient with large tumor
Older patient with small tumor
Repeat at 6 months and then again yearly
Longstanding hearing loss may represent a slow
growing tumor (35)
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First Introduced Leskell in 1969
Gamma Knife
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LINAC
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Uses multiple beams from a linear accelerator
One session
Fractionated Radiotherapy
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Uses 201 ionizing beams of gamma rays from cobalt 60 source
One session
Newer therapy to eradicate cells in different cell cycle stages
Multiple sessions
Goal is to stop tumor growth, not shrink or remove
tumor
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Local control = not requiring salvage therapy
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87 to 100% local control rates all three combined
23% of cases have transient increase tumor
volume due to central necrosis
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6mo to 5yr to disappear
Therefore some patients receive unnecessary salvage
therapy
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Hasegawa et al. 2005 (36)
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317 patients
Median follow up 7.8 years
10 yr local control >92%
Partial or complete radiographic response 62%
Progression free survival
 96% if <15cm3 vs 57% if >15cm3 p<0.001
 Better with no brainstem compression/4th ventricle
obstruction p<0.001
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Most tumor progression within 3 years

Freidman et al. 2006 (37)
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390 patients
Median follow up 40 months
Median dose of 12.5 Gy
5- and 10-year local control 90%
Only 1% of patients required surgery for treatment
failure
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Many different regimens studied
Dose 15-57.6 Gy/3-32fx
Median Follow ups of 48 months
5- year local control of >90%
**Relatively new idea so no long term outcomes
available
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Tumor Control
73.8 to 100% for Radiosurgery
 91.4 to 100% for FSRT

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Tumor Shrinkage
38 to 76.2% for Radiosurgery with single dose
 34 to 76% for FSRT

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Tumor Growth
0-26.2% for Radiosurgery
 0-12.5% for FSRT
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Hearing Preservation
47-71% for Radiosurgery
 57-100%for FSRT
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Defined as G-R class I/II
Early studies 16Gy = 46%
Later Studies 12-13Gy = 68-78% with no change
in control (24)
Prasad et al. (39)
153 patients
 Median follow up of 4.2 years
 Useful hearing preservation rate of 58%
 Size matters

 <1cm3 = 75% hearing preservation
 >1cm3 = 57% hearing preservation
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GK vs FSRT
Andrews et al. 2001 (40)

109 patients
 63 GK at 12Gy
 46 FSRT at 50Gy/25fx
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Follow up was 3 years
33% vs 81% hearing preservation (GK/FSRT)
98% vs 97% local control (GK/FSRT)
Thought is that lower dose in multiple fractions
leads to decreased late normal tissue damage
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GK dose decrease from 16Gy to 12-13Gy
decreased rates from 15% to 0% (41)
LINAC dose decrease of 16Gy to 12.5Gy
showed drop in neuropathy from 4.4% to 0.7%
(37)
RS vs FSRT ranges of 0-52% vs 0-4%(38)
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GK dose decrease from 16Gy to 12-13Gy
decreased rates from 16% to 4.4% (41)
LINAC dose decrease of 16Gy to 12.5Gy
showed drop in neuropathy from 3.7% to 0.7%
(37)
RS vs FSRT ranges of 2.4-29% vs 0-16% (38)
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Hydrocepahlus
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Tinnitus
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3.6%
Malignant transformation
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1.4 to 1.7%
Peritumoral cyst formation
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1.4 to 3.6%
Vertigo
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0.2 to 5%
Ataxia
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0-11% (24), with highest rates in FSRT
0 to 0.3%
3 cases in all studies reviewed with time to presentation of 5, 7.5, and 18
yrs post therapy
Disequilibrium

33% likely due to weaker central compensation (42)
1.
2.
3.
Translabyrinthine Approach
Middle Cranial Fossa Approach
Retrosigmoid-Suboccipital Approach
**All will require discussion/collaboration with
Neurosurgery
ADVANTAGES
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Least cerebellar retraction
Wide exposure of
posterior fossa
No size limit for resection
Facial nerve easily
identified throughout
Ease of facial nerve repair
if damaged/resected
during removal
Low recurrence
Low headaches
DISADVANTAGES


Residual hearing is
sacrificed
Requires abdominal fat
graft
ADVANTAGES

Best hearing
preservation
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
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
<30db PTA
>70% speech
discrimination
Good exposure of
lateral IAC, CPA, and
clivus
Drilling is extradural
decreasing morbidity
DISADVANTAGES
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


Limited to tumors <2cm
in greatest dimension
Temporal lobe
retraction
Must dissect around
facial nerve due to its
superior position
Limited posterior fossa
exposure
ADVANTAGES
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


Can attack any size tumor
Hearing preservation
possible
Wide exposure of
brainstem and lower
cranial nerves
Neurosurgeon familiarity
Consistent facial nerve
identification
DISADVANTAGES
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

Must be medially located
with <2cm CPA extension
Lateral tumors risk injury
to endolymphatic sac and
vestibular labyrinth
Cerebellar retraction
occulomotor
abnormalities and postop
disequilibrium
Increased air embolism
risk (Sitting vs Park Bench
position)

Translabyrinthine


Total Resection 99.5 to 99.7% (44-45)
Near total resection (<25mm2 or 2mm thick)
 Visible on MRI in 50% of patients with 3% risk of
recurrence (46-47)

Middle Cranial Fossa


Total Resection 98% (48)
Retrosigmoid

Total resection 95% (49)
 Serviceable hearing defined as class A/B or
1/2 (24)
 Middle cranial fossa 51%
 Retrosigmoid 31%
 Meyer et al. 2006 (50)
162 consecutive patients via MCF approach
 Class A/B hearing preserved in 41%
 56/113 (50%) with WR >70% preoperatively maintained
that level.

 Tumor 0.2-1.0cm = 59%
 Tumor 1.1-1.4cm = 39%
 Tumor 1.5-2.5cm = 33%

Reporting function at 6-12 month point is gold
standard

Preserved = Grade I/II (24)
 Retrosigmoid 91%
 Middle Cranial Fossa 88%
 Translabyrinthine 77%

Delayed paralysis (>72hrs after surgery)
 Described by Grant et al. 2002
 Incidence 5% (51)
 79% regain postoperative function by 1 yr

Pooled data from 19 studies 360/4297 (8%) rate
(52)




MCF approach 6%
TL approach 8%
RS approach 11%
Occurs at two different time points


POD 2-3 (Early)
POD 10-14 (Late)

Occurs roughly 10% of patients >3 months
postop (52)




RS approach 21%
MCF approach 8%
TL approach 3%
Mechanisms
1.
2.
3.
4.
Bone dust contacting CSF/Meninges  Aseptic
Meningitis
Occipital nerve entrapment
Scarred neck muscles and dura
Migraine

Mortality


1% due to neurovascular injury
Meningitis
1-8%
Aseptic more common than bacterial (bone
dust/inflammation)
 S. aureus most common pathogen



Tinnitus


Balance abnormalities


50% with preop tinnitus will have resolution postop
Occurs in most patients but gone by 6-9 months
Seizure/Hydrocephalus/Stroke (24)

Rare and <2% of cases

Myrseth et al 2005 (53)

Retrospective review 189 patients tumors ≤3cm
 86 by microsurgery vs. 103 by GK
 5.9 year mean follow up
 Local control rates of 89.2% Surgery vs 94.2% GK
 HB 1-2 in 79.8% Surgery vs 94.8% GK p=0.0026
 Quality of life significantly lower in surgery group
compared to gamma knife group
*MCF approach was not utilized

Pollock et al. 2006 (54)

Prospective cohort of 82 patients unilateral VS <3cm
 36 Surgery vs 46 GK
Average follow up of 42 months
 Local control 96% Surgery vs 100% GK p= 0.50
 HB 1/2 in 75% Surgery vs 96% GK p<0.01
 Hearing Preserved 5% Surgery vs 63% GK p<0.001
 Quality of life all statistically better for GK

 Physical functioning
 Bodily pain scores
 Dizziness Handicap Inventory



Vestibular schwannomas are the most common
CPA tumor
Unilateral Tinnitus or SNHL must be evaluated
Tumors <3cm in size treated with radiosurgery




GK or LINAC have comparable results
FSRT may prove more beneficial but requires more than 1
day of treatment
For patients with no serviceable preoperative
hearing, translabyrinthine approach is best choice
For Hearing Preservation options the middle
cranial fossa approach appears to be slightly better
than the retrosigmoid approach due to decreased
rates of complications.





55 y/o female with 2 year history of falls and
disequilibrium
Falls are now progressive and daily
Denies true vertigo just imbalanced
Also has tinnitus, neck spasms, and migraines
She denies any hearing loss but family feels
otherwise

PMHx:


PSHx:


HCTZ, metoprolol, sydol prn, soma, and ambien prn
Allergies:


45pack year history of smoking, -EtOH
Medications:


Noncontributory
SHx:


Partial hysterectomy and R thyroid lobectomy
FHx:


HTN, Hypothyroidism
Sulfa
ROS:

Otherwise negative. No vision or constitutional problems






General: NAD oriented x3
Head: NCAT
Eyes: No nystagmus, PERRLA, EOMI
ENT: TM’s intact, Tuning forks normal
Neck: No masses or lymphadenopathy
Neuro: CN II-XII intact, unsteady Romberg,
tandem gait falling to the left, and left finger to
nose ataxia

Audiogram


Normal hearing with mild high frequency SNHL at
4000Hz bilaterally
ENG
Decreased accuracy on horizontal smooth pursuit
 54% weakness on left air caloric testing


MRI

1.5 to 2cm lesion closely associated with CN
VII/VIII. It is intracanalicular with extension into
CPA. No evidence of brainstem compression or
ventricular obstruction
1.
2.
3.
4.
Finger to nose and gait ataxia
Essentially normal hearing
ENG positive for left lateral canal
weakness
2cm tumor, no hydrocephalus


Patient had previous MRI 2005 showing no
tumor
Therefore it is decided that we perform
suboccipital craniotomy for excision of tumor
Tumor
Tentorium
Cerebelli
Retracted
Cerebellum
CN
VII/VIII
Complex
Tumor
Tentorium
Cerebelli
Retracted
Cerebellum
CN
VII/VIII
Complex
Tumor
Tentorium
Cerebelli
AICA
CN V
Retracted
Cerebellum
CN
VII/VIII
Complex
Tumor
CN VI
Tentorium
Cerebelli
AICA
CN V
Retracted
Cerebellum




Final Pathology: Meningioma
No complications at this point
Tuning forks 256hz and 512hz normal
HB I immediately and 72 hours postoperatively
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