Otosclerosis
Department of Otorhinolaryngoglogy
the 2nd Hospital affliatted to Medical college
Zhejiang University
Xu Yaping
Introduction
• Otosclerosis
1. Primary metabolic bone disease of the otic
capsule and ossicles
2. Results in fixation of the ossicles and
conductive hearing loss
3. May have sensorineural component if the
cochlea is involved
􀂄Genetically mediated via autosomal dominant
transmission with incomplete penetrance (40%)
and variable expressivity.
History of Otosclerosis and Stapes surgery
􀂄 1704 – Valsalva first described stapes fixation
􀂄 1857 – Toynbee linked stapes fixation to hearing loss
􀂄 1890 – Katz was first to find microscopic evidence of
otosclerosis
􀂄 1893 – Politzer described the clinical entity of
“otosclerosis”
􀂄 1890 – Bacon describes medical therapy for the
condition, and supports the common view that
“surgery should not be considered for a moment.“
Epidemiology
•
10% overall prevalence of histologic otosclerosis
•
1% overall prevalence of clinically significant otosclerosis
•
Clinical otosclerosis ––2:1 (W:M)
•
Possible progression during pregnancy (10%-17%)
•
Bilaterality more common (89% vs. 65%)
•
15-45 most common age range of presentation,
increases with age
Pathophysiology
•
1.
2.
3.
Osseous dyscrasia
Resorption and formation of new bone
Limited to the temporal bone and ossicles
Inciting event unknown,
many theories:
Hereditary, endocrine, metabolic, infectious,
vascular, autoimmune,hormonal .
•
Most common sites of involvement
1. 􀂄Fissula ante fenestrum
2. 􀂄Round window niche (30%-50% of cases)
3. 􀂄Anterior wall of the IAC
Histology
otosclerosis has two main forms:
1. an early of spongiotic phase (otospongiosis)
multiple active cell groups including
osteocytes, osteoblasts, and histiocytes.
2. a late or sclerotic phase: dense sclerotic bone
forms
Non-clinical foci of otosclerosis
Bipolar involvement of the footplate
Round Window
Diagnosis of Otosclerosis
􀂄1. Most common presentation
􀂄Women age 20 - 30
􀂄2. Conductive or Mixed hearing loss
slowly progressive,bilateral (80%),asymmetric
􀂄Tinnitus (75%)
a complete history:
1. Age of onset of hearing loss
2. Progression
3. Laterality
4. Associated symptoms
•
Dizziness
•
Otalgia
•
Otorrhea
•
Tinnitus
• Family history
􀂄2/3 have a significant family history
􀂄Particularly helpful in patients with severe or
profound mixed hearing loss
• Prior otologic surgery
• History of ear infections
• Vestibular symptoms
􀂄25%
􀂄Most commonly dysequilibrium
􀂄Occasionally attacks of vertigo with rotatory
nystagmus
Physical Exam
• Otomicroscopy
Most helpful in ruling out other disorders
􀂄Middle ear effusions
􀂄Tympanosclerosis
􀂄Tympanic membrane perforations
􀂄Cholesteatoma or retraction pockets
􀂄Superior semicircular canal dehiscence
Schwartze’’s signs ( by Schwartze in 1873)
􀂄Red hue behind the tympanic membrane (in oval window niche
area)
􀂄10% of cases
• Pneumatic otoscopy
􀂄Distinguish from malleus fixation
• Tuning forks
􀂄1. Hearing loss progresses form low frequencies to high
frequencies
􀂄 2. 256, 512, and 1024 Hz TF should be used
3. Rinne
􀂄256 Hz ––negative test indicates at least a 20 dB ABG
􀂄512 Hz ––negative test indicates at least a 25 dB ABG
(air-bone gaps)
Differential Diagnosis
1. Ossicular discontinuity:A.conductive loss of 60 db
B. type Ad tympanogram
2.Congenital stapes fixation:A.25% incidence of other
congenital anomalies
B. non-progressive CHL
3.Malleus head fixation: when congenital, associated
with other stigmata (aural atresia).
4.Paget’’s disease: diffuse involvement of the bony
skeleton
5.Osteogenesis imperfecta: presence of blue sclera
6.Superior semicircular canal dehiscence: vertigo
or eye movements with loud noise
Audiometry
􀂄Tympanometry
􀂄Impedance testing
Acoustic reflexes
􀂄Pure tones
As (s-stiffness curve) tympanogram is characteristic of advanced otosclerosis
Acoustic Reflexes
•
1.
2.
3.
4.
Otosclerosis has a predictable pattern of
abnormal reflexes over time
Reduced reflex amplitude
Elevation of ipsilateral thresholds
Elevation of contralateral thresholds
Absence of reflexes
Pure Tone Audiometry
• Most useful audiometric test for otosclerosis
􀂄Characterizes the severity of disease
􀂄Frequency specific
• Carhart’’s notch
􀂄Hallmark audiologic sign of otosclerosis
􀂄Decrease in bone conduction thresholds
􀂄5 dB at 500 Hz
􀂄10 dB at 1000 Hz
􀂄15 dB at 2000 Hz
􀂄5 dB at 4000 Hz
early stage
middle stage
• late stage
Imaging
•
Computed tomography (CT) of the temporal bone
􀂄Proponents of CT for evaluation of otosclerosis
Pre-op
1. Characterize the extent of otosclerosis
2. Severe or profound mixed hearing loss
3. Evaluate for enlarge cochlear aqueduct
Post-op
1. Recurrent CHL
2. Re-obliteration vs. prosthesis dislocation
3. Vertigo
Management options
• Medical: Sodium Fluoride,Bisphosphonates,Vitamin D
and Calcium
• Amplification:Non-surgical candidates-wearing hearing
aids.
• Surgery: Stapedectomy vs. Stapedotomy
• Combinations
Surgery
• Best surgical candidate
1. Previously un-operated ear
2. Good health
3. Unacceptable ABG
4. 25 to 40 dB
5. Negative Rinne test
6. Excellent discrimination
7. Desire for surgery
Tympanosclerosis
• Definition: a whitish "plaque" of the TM.
• Pathology: submucosal hyaline degeneration in
the TM and middle ear mucosa.
• extensive involvement of the TM and ossicle
amy result in conductive hearing loss.(air-bone
gap >40dB)
• medical therapy and pressure equalization tubes
(PETs) do not prevent progression of disease.
The end, thank you!