Otosclerosis is a primary bone disease that causes fixation of the ossicles in the middle ear, resulting in conductive or mixed hearing loss. It is caused by abnormal bone remodeling where mature bone is removed and replaced with woven bone. It commonly affects the oval window area. Symptoms include gradual onset of hearing loss that progresses slowly and is usually noticed first around age 30. Diagnosis involves audiometric testing showing a conductive hearing loss. Treatment options include hearing aids, medical management to slow progression, or stapes surgery to restore hearing if meeting criteria. Stapedotomy and stapedectomy are surgical procedures to replace the stapes bone with a prosthesis in order to improve sound conduction.

1. Otosclerosis
Dr Rajashri S Mane

2. • Definition
– Primary metabolic bone disease of the otic capsule and
ossicles.
– It causes fixation of the ossicles (stapes).
– It results in conductive or mixed hearing loss.
– It is genetically-mediated via autosomal dominant
transmission.

3. • A primary disease of the bony otic capsule characterized by
abnormal removal of mature bone by osteoclasts and
replacement with woven bone of greater thickness, cellularity
and vascularity.

4. Epidemiology
Race incidence of microscopic otosclerosis
Caucasian 10%
Asian 5%
African American 1%
Native American 0%

5. Epidemiology
• Sex variation (M:F=1:2.5)
– Women more commonly seek medical attention for hearing loss
secondary to otosclerosis,
– histologic studies prevalence of otosclerosis show no difference in
men versus women.

6. Epidemiology
• Age
– The incidence of otosclerosis increases with age.
– The most common age group presenting with hearing loss from
otosclerosis is 15-45 years,
– however it has been reported to manifest as early as 7 years and as
late as the mid 50s.

7. Etiology
• Many theories have been proposed such as
– hereditary, 54% of patients present with family history
– endocrine, women with pregnancy worse her hearing
– metabolic, enzyme abnormal was pathogen
– infectious, virus was identified in the lesion
– vascular,
– autoimmune,
• None have be proven. Hormonal factors have been suggested to play a
role in otosclerosis based on the observation that pregnancy sometimes
accelerates the progression of the disease.

8. Pathophysiology
• Otosclerosis (otospongiosis) is an osseous dyscrasia,
• Limited to the temporal bone, and
• Characterized by resorption and formation of new bone in the area of the
ossicles and otic capsule.

9. Pathophysiology
• The most common site - the anterior oval window near the fistula ante
fenestrum.
• When both the anterior and posterior ends of the footplate are involved it
is termed “bipolar” involvement or fixation (if the footplate is immobile).
• If only the footplate is involved, it is sometimes referred to as a “stapedial
otosclerosis”.
• When the entire footplate and annular ligament are involved it is known
as an obliterated footplate or obliterative otosclerosis.

10. The round window is involved in
approximately 30% to 50% of cases
Other areas involved are the apex of
the cochlea, the cochlear aqueduct,
the semicircular canals, and the
stapes footplate itself

11. Types of Stapedial fixation
• Anterior Focus
– Most common, at fissula ante fenestram
• Posterior Focus
– Lesion spreading from posterior oval window to annular ligament
• Circumferential
– Lesion flows across the ligament totally obliterating the annular
ligament
• Biscuit type
– Lesion replacing entire footplate, but no involvement of annular
ligament leading to a solid footplate
• Obliterative
– Completely obliterates the oval window
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12. Pathophysiology
• Otosclerosis has two main forms:
– An early of spongiotic phase (otospongiosis)
• The early phase is characterized by multiple active cell groups
including osteocytes, osteoblasts, and histiocytes.
• It develops a spongy appearance because of vascular dilation
secondary to osteocyte resorption of bone surrounding blood
vessels.
• This can be seen grossly as red hue behind the tympanic
membrane termed “Schwartze's sign”

13. Pathophysiology
• Second form
– A late or sclerotic phase
• dense sclerotic bone forms in the areas of previous resorption.
• Both the sclerotic and spongiotic as well as intermediate phases
may be present at the same time.
• Otosclerotic foci always begin in endochondral bone but may
progress to involve endosteal and periosteal layers and even enter
into the membranous labyrinth.
Cochlear otosclerosis manifests with sensorineural hearing loss

14. Pathophysiology
• Microscopically, a focus of active otosclerosis reveals finger projections of
disorganized bone, rich in osteocytes particularly at the leading edge.
• In the center of the focus, multinucleated osteocytes are often present.
In the sclerotic phase,

15. Histopathology
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Histologic otosclerosis with small focus in the
anterior oval window (arrow).
Clinical otosclerosis. The lesion has spread
across the annular ligament and fixed the
stapes.

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17. History
• Gradual onset of hearing loss progressing slowly
• In 70% cases hearing loss is bilateral
• Usually becomes apparent around the age of 30
• Loss noticeable when it reaches 25 to 30 dB
• Paracusis of Willis (characteristic of CHL)
• Unilateral loss noticed even later, problem with localization of
sound
• Tinnitus
• Positive family history
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18. Physical Examination
• Otoscopy
Schwartze sign; red blush occasionally seen over promontory or
anterior to oval window
• Pneumo-otoscopy used to rule out other causes of CHL such as
middle ear serous fluid or small perforation
• Tuning Fork Test
– Weber Test
– Rinne Test
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19. • Weber test
– Performed with 512 Hz tuning fork
– Lateralizes to ear with conductive or greater conductive loss
– Lateralizes with 5 dB of conductive hearing loss
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20. • Rinne test
– Performed with 512 or 1024 Hz tuning forks
– Compares patient perception of loudness of air conduction
versus bone conduction
– If BC > AC on 512 Hz fork
• Loss is 15 – 20 dB
– If BC > AC on 1024 Hz fork
• Loss is at least 30 db
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21. • Schwabach test: Normal bone conduction
• Gelle test: negative

22. Hearing Loss
• Conducting Hearing Loss (CHL)
– Stapedial fixation
• Sensorineural Hearing Loss (SNHL)
– Cochlear otosclerosis
• Mixed
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23. Audiometry
• Pure Tone Audiometry
– Loss of air conduction at lower
frequencies
– Bone conduction normal,
sometimes shows a dip at 2000 Hz
(Cahart’s notch) which disappears
after successful surgery.
• Speech Audiometry
– Normal except in those with
cochlear involvement.
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24. • Impedance Audiometry
– Tympanometry : As type curve
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25. • Acoustic reflex
– Measure of movement of stapes at stimulus
– Reflex is absent in otosclerosis
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Progressive changes in the
configuration of the acoustic reflex
with stapedial fixation.
A) healthy reflex with a sustained
change in compliance as long as
stimulus is on.
B) Diphasic reflex with on-off
pattern. Seen in cases of early
otosclerotic fixation.
C) Absent acoustic reflex

26. Radiological Investigations
• High resolution CT scan
– Shows subtle areas of demineralisation
– In case of cochlear involvement it shows “double ring sign”
• MRI
– Done for patients with unusual presentation
– Detects congenital anomalies of cochlea
– Excludes retrocochlear pathology eg. Acoustic neuroma
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28. Treatment Options
• Hearing aid
• Surgical management
• Observation
• Medical management
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29. Medical management
• Aim is to Stabilize the disease by
 reduction of the osteoclastic bone resorption increase osteoblastic
bone formation
 Inhibits proteolytic enzymes that are cytotoxic to cochlea.
• Slows the progression of sensorineural hearing loss
• Not commonly used
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30. • Sodium Fluoride therapy
Contraindicated in patients with
 Chronic nephritis
 Chronic rheumatoid arthritis
 Pregnant and lactating women
 Children
• Bisphosphonates
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31. Hearing Aid
• Very effective in early stage of disease
• But can be used in advance stage, if:
 Surgery is contraindicated
 Patient refuses the surgery
 In far-advance cases it is required, even after stapedotomy
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32. Surgical Management
• Poorer ear always chosen for surgery
• Done preferably under local anesthesia so patient can notify
surgeon if vertigo occurs during procedure
• Options are:
 Stapedotomy
 Stapedectomy
• Lesser complications due to use of LASER now.
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33. Selection Criteria
• Hearing threshold is 30dB or worse
• AB gap at least 15dB
• Rinne’s negative for 256 Hz and 512 Hz
• Speech Discrimination Score is 60% or more
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34. Prosthesis
 Teflon piston
 Stainless steel piston
 Platinum Teflon piston
 Titanium Teflon piston
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35. Summary of small fenestra stapedotomy
• Anethesia injected
• Incisions at lateral process of malleus and inferiorly
• Tympanomeatal flap elevated
• Adequate exposure (facial nerve superiorly, pyramidal process inferiorly)
• Distance from incus to footplate measured (usu. 4.5mm)
• Microdrill used to create fenestra
• Prosthesis placed on incus and crimped firmly in place.
• Incudostapedial joint separated and stapedial tendon sectioned
• Stapes superstructure fractured and removed
• Prosthesis checked
• Tympanomeatal flap returned to normal position
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36. Stapedotomy v/s Stapedectomy
• Stapedotomy
oSafer
oLower rate of high frequency sensorineural
hearing loss post op.
• Stapedectomy
oLess chances of recurrence
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37. Postoperative Care
• Patient’s head elevated to 30o to reduce
perilymph pressure in vestibule
• Bed rest for at least 1 hour
• If no vertigo on getting up then patient can go
home
• Patients can resume air travel after 5 days
• Follow up with audiogram in 3 weeks
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38. Contraindications
• Only hearing ear
• Meniere’s disease
• Occupation
 Experience frequent change in pressure
 Works in noisy surrounding
• Otitis externa
• Perforated TM
• Young children
• Poor state of health
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40. Intra-Operative Complications
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• Exposed, overhanging Facial Nerve (9%)
• Chorda tympani nerve damage (30%)
• Solid or Obliterated Footplate
• Floating Footplate
• Persistent Stapedial Artery
• Perilymph Gusher
 Managed by placing tissue graft over oval window
• Tympanic Membrane perforation
• Intraoperative vertigo due to long prosthesis
• Fixed Malleus

41. Post-Operative Complications
• SNHL
• Vertigo
• Facial paralysis
• Tinnitus
• Taste disturbance
• Perilymph fistula
• Dead ear (1%)
• Iatrogenic tympanic membrane perforation
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