acoustic neuroma: an overview… · acoustic neuroma benign, intracranial tumor slow-growing...
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Acoustic Neuroma: An Overview
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Moderator:Carolyn Smaka, Au.D., Editor-In-Chief
Jill Messina, Au.D., CCC-A, & Robert A. Battista, M.D., F.A.C.S., The Ear Institute of Chicago
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Acoustic Neuroma: An Overview
Robert A. Battista, MD, FACSAssistant Professor
Northwestern University Medical SchoolNorthwestern University Medical School
Jill Messina, AuD, CCC-A
Ear Institute of Chicago, LLCHinsdale/Chicago/Elk Grove Village, IL
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Acoustic Neuroma
Benign, intracranial tumor
Slow-growing
Originate: schwann cells of vestibular nerve Originate: schwann cells of vestibular nerve
“Vestibular schwannoma”: most accurate term
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Acoustic Neuroma: Epidemiology
6 - 8% of intracranial tumors
Incidence: 10‡ - 20*/1,000,000
2 500 3 500 new cases/year ~ 2,500 - 3,500 new cases/year
‡Nestor JJ, et al. Arch Otolaryngol Head Neck Surg 1988; 114:680.
*Stangerup SE, et al. J Laryngol Otol 2004;118:622-7.
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Acoustic Neuroma: Types
Two Forms Sporadic: 95%
Neurofibromatosis 2 (NF2): 5%
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Acoustic Neuroma: Symptoms
Unilateral sensorineural hearing loss > 95%
Unilateral tinnitus
Dysequilibrium 50%y q
Facial Anesthesia ~ 5 - 20%
Vertigo 19%
Facial twitching/weakness < 5%
Headache
Acoustic Neuroma: Diagnosis
Audiogram: screening
ABR: screening
MRI Brain/Internal Auditory Canal with MRI Brain/Internal Auditory Canal with gadolinium
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Acoustic Neuroma: Hearing Loss
History 90%: Slowly progressive sensorineural hearing
loss
~10%: Sudden, SNHL
Type of Hearing Loss ~2/3: High-frequency SNHL
1/3:
Low-frequency SNHL
Mid-frequency SNHL
Normal hearing
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Acoustic Neuroma: Treatments
A. Observation (Serial radiologic evaluation) Relatively asymptomatic Age > 65 yrs
B. Stereotactic radiosurgery Elderly/Infirm Tumor < 3cm Residual/Recurrent tumor Patient preference
C. Microsurgical removal All other cases
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Considerations for Management
Patient’s age
Medical status
Size of tumorS e o tu o
Tumor related symptoms and signs
Patient’s reliability and attitude
Tumor growth rate
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A. Observation: Risks
Cranial nerve dysfunction
Brainstem compression
(Death) (Death)
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B. Stereotactic RadiosurgeryB. Stereotactic Radiosurgery
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Translabyrinthine
Retrosigmoid (Suboccipital)
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Microsurgical Approaches
Hearing Loss Translabyrinthine
Hearing Preservation (potential) Middle Fossa Retrosigmoid
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Surgery: Hearing Preservation Positive Prognostic Indicators
Tumor: < 1.5 cm
Audiogram: <50 dB PTA/ >50% WRS
ABR: Normal ABR: Normal
VNG caloric: Reduced
VEMP: normal
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Caloric
VEMP
•Reduced/Absent Caloric•VEMP: normal
•Normal Caloric•VEMP: reduced/absent
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Conventional Audiometry
- Most common abnormality is an asymmetric high frequency hearing loss
Ear Institute of Chicago, LLC
Right LeftFrequency (Hz) Frequency (Hz)
0 0
10 10
20 20
30 30
40 40
50 50
60 60
70 70
80 80
Date:
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Inte
ns
ity
Inte
ns
ity
80 80
90 90
100 100
110 110
120 120
HL % HL %
55
9665/M
84
Speech
SRT
L 25 33
PTA
R 15 15
Stim Ear R L R LMeas. Ear L R R L
500 Hz1000 Hz 2000 Hz4000 Hz
Acoustic Reflex Thresholds (dBHL)R LEquivalent Volume (cm3)Peak Pressure (daPa)Static Admittance (mmhos)
Tympanometry
DNT
DNT
Conventional Audiometry
Normal hearing or even symmetric hearing does NOT exlude an acoustic neuroma
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Right LeftFrequency (Hz) Frequency (Hz)
0 0
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50 50
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70 70
80 80
Date:
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Inte
ns
ity
Inte
ns
ity
80 80
90 90
100 100
110 110
120 120
HL % HL %
50/M
10045
100
Speech
SRT
L 5 7
PTA
R 10 7
Stim Ear R L R LMeas. Ear L R R L
500 Hz 90 80 80 901000 Hz 80 75 80 852000 Hz 80 80 75 854000 Hz 90 80 85 85
Acoustic Reflex Thresholds (dBHL)R LEquivalent Volume (cm3) 1.5 1.6Peak Pressure (daPa) 30 25Static Admittance (mmhos) 0.9 0.8
Tympanometry
Audiometric Testing
Acoustic Reflexes
Speech Discrimination Often worse than expected; rollover (decreased
ability to understand words with increased volume)
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ABR Testing For Acoustic Neuroma
Less sensitive/less expensive than MRI
Characteristic findings:
Wave I, no waves III or V
Delayed I-III latency
Delayed wave V latency
High false-positive/false-negative rates (pts with small tumors can have normal ABR’s)
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ABR Testing, cont.
Tumor Size: more predictive than location
> 1.5 cm : ABR = 92-98% accuracy
< 1.5 cm : ABR = 60-70% accuracy
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Schmidt et.al (2001)
ABR Testing, cont.
ENG/VNG Testing
Most pt’s with an AN have a unilateral caloric weakness (however, weakness could be from other causes)
ENG/VNG not specific
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ENG/VNG Testing, cont.
Example:
VEMP testing
VEMPs absent or decreased amplitude in approximately 80% if patients with vestibular schwanomma (Murofushi et. al., 1998)
Saccule innervated by inferior vestibular nerve
Ear Institute of Chicago, LLC
Right LeftFrequency (Hz) Frequency (Hz)
0 0
10 10
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Inte
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Inte
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80 80
90 90
100 100
110 110
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HL % HL %
55
10045
100
Speech
SRT
L 5 10
PTA
R 15 25
Stim Ear R L R LMeas. Ear L R R L
500 Hz NR NR NR 851000 Hz NR NR NR 852000 Hz NR NR NR 854000 Hz NR NR NR 95
Acoustic Reflex Thresholds (dBHL)R LEquivalent Volume (cm3) 1.4 1.3Peak Pressure (daPa) 25 25Static Admittance (mmhos) 1.4 1.1
Tympanometry
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Case Study #2
59 y.o. male
Left-sided tinnitus, hearing loss (5 year history), and vertigo
MRI showed intracanalicular small acoustic neuroma (1.1 cm mass)
Right LeftFrequency (Hz) Frequency (Hz)
0 0
10 10
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50 50
60 60
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Date:Case Study #2
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Inte
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Inte
ns
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80 80
90 90
100 100
110 110
120 120
HL % HL %
50
10065/M
84
Speech
SRT
L 35 32
PTA
R 15 10
Stim Ear R L R LMeas. Ear L R R L
500 Hz DNT DNT 75 801000 Hz DNT DNT 80 802000 Hz DNT DNT 80 804000 Hz DNT DNT 80 80
Acoustic Reflex Thresholds (dBHL)R L
Equivalent Volume (cm3)Peak Pressure (daPa)Static Admittance (mmhos)
DNT
Case Study #2, cont.
ABR: Abnormal (prolonged latencies)
VNG: Normal
Retrosigmoid craniotomy and removal of the Retrosigmoid craniotomy and removal of the acoustic tumor with attempted preservation of the seventh and cochlear division of the eighth nerve
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Right LeftFrequency (Hz) Frequency (Hz)
0 0
10 10
20 20
30 30
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50 50
60 60
70 70
80 80
Date:Case Study #2, cont.
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Inte
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Inte
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80 80
90 90
100 100
110 110
120 120
HL % HL %
60
10075/55
76
Speech
SRT
L 55/40 57
PTA
R 10 13
Stim Ear R L R LMeas. Ear L R R L
500 Hz1000 Hz 2000 Hz4000 Hz
Acoustic Reflex Thresholds (dBHL)R L
Equivalent Volume (cm3)Peak Pressure (daPa)Static Admittance (mmhos)
DNT
DNT
Case Study #3
58 y.o. female
Sudden right hearing loss, tinnitus, and dizziness
Similar incident on left side 20 years ago
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Right LeftFrequency (Hz) Frequency (Hz)
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Inte
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Inte
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80 80
90 90
100 100
110 110
120 120
HL % HL %
100
0/10105
0/10
Speech
SRT
L 85 80
PTA
R 80 72
Stim Ear R L R LMeas. Ear L R R L
500 Hz NR NR NR NR1000 Hz NR NR NR NR2000 Hz 100 NR 100 NR4000 Hz NR NR NR NR
Acoustic Reflex Thresholds (dBHL)R L
Equivalent Volume (cm3) 1.8 1.7Peak Pressure (daPa) 25 25Static Admittance (mmhos) 2.2 3.8
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Case Study #3, cont.
MRI revealed 4 x 6.5 mm acoustic neuroma on the LEFT side
Patient underwent translabyrinthine removal of LEFT acoustic neuroma
Two months later patient was implanted with cochlear implant on RIGHT side
Ear Institute of Chicago, LLC
Right LeftFrequency (Hz) Frequency (Hz)
0 0
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80 80
Date:Case Study #3, cont.
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Inte
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Inte
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CC
C CC
C
C
80 80
90 90
100 100
110 110
120 120
HL % HL %
Speech
SRT
L
PTA
R
Stim Ear R L R LMeas. Ear L R R L
500 Hz1000 Hz 2000 Hz4000 Hz
Acoustic Reflex Thresholds (dBHL)R LEquivalent Volume (cm3)Peak Pressure (daPa)Static Admittance (mmhos)
Tympanometry
DNT
DNTDNT
Bibliography
Nestor JJ, et al. The incidence of acoustic neuromas. Arch Otolaryngol Head Neck Surg 1988; 114:680.
Murofushi T, Matsuzaki M, Mizuno M. Vestibular evoked myogenic potentials in patients with acoustic neuromas. Arch Otolaryngol Head Neck Surg 1998; 124: 509 512Otolaryngol Head Neck Surg. 1998; 124: 509-512.
Schmidt R, Sataloff R, Newman J, et al. The sensitivity of auditory brainstem response testing for the diagnosis of acoustic neuromas. Arch Otolaryngol Head Neck Surg. 2001; 127: 19-22.
Stangerup SE, et al. Increasing annual incidence of vestibular schwannoma and age at diagnosis. J Laryngol Otol 2004;118:622-7.