Download Facial nerve neuroma

Facial nerve schwannomas
R3 康焜泰
Introduction
 Uncommon disease
 Originate any segment of facial nerve
 CP angle peripheral branch in the
parotid gland
 Varying clinical symptoms
 Diagnosis: difficult
Anatomy of facial nerve
Segmental Description of the Facial Nerve and
Central Connections
Segment
Location
Length,
mm
Supranuclear
Cerebral cortex
NA?/td>
Brain stem
Motor nucleus of facial
nerve, superior
salivatory nucleus,
tractus solitarius
NA?/td>
Meatal segment
Brain stem to IAC
13-15
Labyrinthine segment
Fundus of IAC to facial
hiatus
3-4
Tympanic segment
Geniculate ganglion to
pyramidal eminence
8-11
Mastoid segment
Pyramidal process to
stylomastoid foramen
10-14
Extratemporal segment
Stylomastoid foramen to
pes anserinus
15-20
 Intracranial segment  brainstem in a
recess adjacent to the pons, cross CP
angle medial to vestibuloacoustic nerve
Meatal segment (13-15 mm)
由 Brain stem  IAC
Internal auditory canal
Labyrinthine segment (3-4 mm)
Within narrowest part of fallopian canal to geniculate
ganglion
Tympanic segment (8-11 mm)
Geniculate ganglion to pyramidal eminence
Mastoid segment (8-11 mm)
Pyramidal process to stylomastoid foramen
Extratemporal branch: stylomastoid foramen
1. Temporal 2.Zygomatic 3. Buccal 4. Mandibular 5.
Cervical
Brain stem : facial nuclei
Facial nerve function
 1.Brachial motor: facial expression
 2.Visceral motor: lacrimation, salivation
(submandibular, sublinguar, nose,
palate)
 3.Special sensory: taste (tongue ant.
2/3)
 4.General sensory: auricular sensation
Branches of facial nerve
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GSPN: geniculate ganglion GSPN sphenoplalatine ganglion
 lacrimal and palatine gland 支配 lacrimation & salivation
Nerve to stapedius muscle : 由 proximal mastoid segment 分出
Chorda tympani: 由 distal mastoid segment 分出 , 和 lingual
nerve 一同支配 sublingual gland 和 submandibular gland, Taste
Sensory auricular branch
 Sensation of posterior external auditory canal & inferior
pinna of ear
 Some axons may arise from vagus (Arnold's nerve)
Motor: Facial muscles
Facial nerve anatomy

FIGURE LEGEND
1. Facial nerve
nucleus
2. Trigeminal nerve:
Spinal nucleus
3. Superior salivary
nucleus
4. Solitary tract
5. Porus acusticus
internus
6. Meatal foramen
7. Greater petrosal
nerve
8. Sphenopalatine
ganglion
9. Maxillary nerve
10. Lacrimal gland
11. Deep petrosal
nerve
12. Vidian nerve
13. Nerve to glands of
nose and palate
(motor fibers to
levator palati muscles)
14.Minor petrosal
nerve anastamosis
15. Stapedial nerve
16. Chorda tympani
17. Auricular branch
18. Stylomastoid
foramen
19. Lingual nerve
20. Submandibular
ganglion
21. Submandibular
gland
22. Sublingual gland
Facial nerve imaging-CT
Facial nerve imaging-MRI
 T1
T2
Facial nerve schwannoma
 Rare
 1931 Schmidt: First report
 1972 Saito and Baxter: report 0.8%
occult FNS incidence in a study of 600
temporal bone
 Now, more than 400 reported cases
 Benign, encapsulated, slow-growing
tumor
 Age: 7-81 y/o, mean age 41.7 y/o
 No sexual predominant
 No side preference
 No bilateral FNSs reported
Locations
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Arise from any segment of facial nerve from
CP angle to peripheral branch in parotid
gland
The geniculate ganglion is frequently
involved and is often affected proximally or
distally.
Labyrinthine: 43.5%
Tympanic: 42.8%
Mastoid: 36.7%
IAC: 24.3%
CP angle: 17.8%
Extratemporal peripheral: 15%
Sherman et al, 2002
Symptoms
 Progressive facial paresis 73%
 Hearing loss 50%
 Tinnitus 13%
 Dizziness 11%
 EAC mass 11%
 Pain 11%
 Otorrhea 6%
Pre-operative evaluation
 Detailed history, clinical symptoms, and
radiologic data
 However, diagnosis is difficult
Pre-operative histopathologic
diagnosis
Fine needle aspiration:
 Not possible for some FNS cases
 Limited value for diagnosis
 Balle and Greisen(1984): repeated FNA not
contribute to correct preoperative diagnosis in
their 2 intraparotid FNSs.
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Chong et al(2000): only 1 patient had preoperative diagnosis suspicious of
schwannoma among 5 intraparotid FNS
Image study
 CT and/or MRI provide important for
determining the localization, nature, and
extent of tumor.
CP angle and IAC
Characterized by sensorineural hearing loss
 Because more thinly myelinated sensory
fibers of the acoustic nerve are more
vulnerable to compression than more thicky
myelinated motor fiber of the facial nerve
 May cause both acoustic and facial nerve
symptoms
 May clinically and radiologically indistinguish
from acoustic neuroma
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CP angle and IAC
Labyrinthine segment
 Slowly progressive facial paresis and
sensorineural hearing loss
 Schwannoma in the geniculate ganglion
grow silently before facial nerve
symptoms and hearing loss present
Geniculate ganglion
Tympanic segment
 Progressive facial paresis, fullness in
the ear and conductive hearing loss
 Tend to first cause conductive hearing
loss by ossicular interference
Tympanic segment
Tympanic segment
Mastoid segment
 Progressive facial paresis, otorrhea,
conductive hearing loss
Peripheral segment
 Mass in the parotid gland
 Slowly progressive facial paresis
Multi-segment
 Usually accompanied by facial nerve
symptoms
Multi-segment
 Facial nerve schwannoma are often
sausage-shaped, expanding long
segment of facial nerve
Differential Diagnosis
 Acoustic neurinoma
 Chronic otitis media with cholesteatoma
 Dermoid cyst
 Benign parotid tumor
Treatment
 Controversial because facial paralysis is
inevitable after surgical resection.
 Complete surgical resection+facial
nerve reconstruction is the most
recommended modality.
Treatment
 Some authors advise observation
rather than surgical excision
 1. Slow growing, benign tumor
 2. Many patient do not present
significant facial paralysis
  suggest delay surgery until patient
exhibit > H-B grade III
  tumor followed by radiologic imaging
Treatment
 Some authors advise facial nerve
decompression
 Angeli and Brackmann(1997): 4
patients treated with decompression
sugery HB grade I and grade II
postoperatively
Treatment
 Surgical approach is based on tumor
location, extent, and hearing level
 Prepare to explore tumor from CPA to
stylomastoid foramen
Treatment
 Tumor intracranial :
 retrosigmoid approach
 Tumor from CPA, IAC, or labyrinthine
segment
 No serviceable hearing:
 translabyrinthine approach or
transotic approach
 Good hearing:
 middle fossa approach
 Tumor from tympanic or vertical
segment:
 transmastoid apraoch
 Tumor from peripheral segment:
 superficial parotidectomy
Treatment-Gamma knife
 1783 schwannoma of CP angle treat by
Gamma knife surgery from 1992-2003
in Timone University Hospital, France
 11 patients:
 9 involve tympanic or mastoid segment
of facial nerve
 2 previous microsurgery
Prognosis
 Excellent
 Morbidities: facial paralysis, hearing
loss, CSF leak, meningitis, and
recurrence
Post-operative facial nerve
paralysis
 Sataloff et al(1995): remove tumor with
facial nerve preservation in 25% cases
 Interposition nerve graft:
 - greater auricular nerve: obtain from
neighboring
 - hypoglossal nerve:
 - direct anaastomosis without a graft:
rare
Recurrence
 Rare
 Janecka and Conley(1987): report only
2 recurrences after surgery among 30
FNS cases
Reference
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1.Shirazi MA, Leonetti JP, Marzo SJ, Anderson DE.Surgical Management of
Facial Neuromas: Lessons Learned.Otol Neurotol. 2007 Jul 26
2.Lee JD, Kim SH, Song MH, Lee HK, Lee WS.Management of facial nerve
schwannoma in patients with favorable facial function.Laryngoscope. 2007
Jun;117(6):1063-8.
3.Litre CF, Gourg GP, Tamura M, Mdarhri D, Touzani A, Roche PH, Regis
J.Gamma knife surgery for facial nerve schwannomas.Neurosurgery. 2007
May;60(5):853-9.
4.Park HY, Kim SH, Son EJ, Lee HK, Lee WS.Intracanalicular facial nerve
schwannoma.Otol Neurotol. 2007 Apr;28(3):376-80.
5.Kreeft A, Schellekens PP, Leverstein H.Intraparotid facial nerve schwannoma.
What to do? Clin Otolaryngol. 2007 Apr;32(2):125-9.
6.Weber PC, Osguthorpe JD.Facial nerve neuroma management.Skull Base
Surg. 1998;8(1):51-5.
7.Chi FL, Wang ZM, Chen ZY, Wu YZ.Diagnosis and management of facial
nerve neuromas
8.Senthilvel E, McConn Walsh R, Brett FM, Rawluk D.Facial nerve schwannoma
of the internal auditory canal.Ir J Med Sci. 2006 Jan-Mar;175(1):74-6.
9.Wiggins RH 3rd, Harnsberger HR, Salzman KL, Shelton C, Kertesz TR,
Glastonbury CM.The many faces of facial nerve schwannoma.AJNR Am J
Neuroradiol. 2006 Mar;27(3):694-9.
10.Kirazli T, Oner K, Bilgen C, Ovul I, Midilli R.Facial nerve neuroma: clinical,
diagnostic, and surgical features.Skull Base. 2004 May;14(2):115-20.
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