Otosclerosis

Otosclerosis is defined as hereditary localized disease of bone derived from the otic capsule characterized by alternating phases of bone formation and resorption
The mature lamellar bone is resorbed and replaced by an immature woven bone of greater thickness, cellularity and vascularity
First described by Politzer in 1893
Types of Otosclerosis
Stapedial
Cochlear: Round window and Promontory
Mixed: Stapedial + cochlear
Malignant: Rapidly progressing cochlear lesion with severe sensori-neural deafness

Types of Stapedial otosclerosis
1. Anterior focus (commonest): 2 mm anterior to oval
window , fissula ante fenestrum, more unstable
2. Posterior focus: 2 mm behind oval window
3. Circumferential: involves footplate margin only
4. Biscuit type: footplate involved, margin is free
5. Obliterative : Obliterates the oval window completely

1. Otosclerosis
Dr. Krishna Koirala
29-05-2023

2. Definition
•Hereditarylocalizeddiseaseofbonederivedfromthe
oticcapsulecharacterizedbyalternatingphasesof
boneformationandresorption
•Thematurelamellarboneisresorbedandreplaced
byanimmaturewovenboneofgreaterthickness,
cellularityandvascularity
•FirstdescribedbyPolitzerin1893

3. •New bone
–Spongy and more vascular in otospongiosis
(Active Stage)
–Thicker and more denser in otosclerosis
(Inactive Stage)

4. Epidemiology
•Exactetiology-unknown
•Factors:
–Genetic:Autosomaldominantwithvariablepenetrance
–Race:Commoninwhiteraces&Indians
–Sex:Female:Male=2:1
–Age:Commonin20-40years
–Hormonalinfluence:Rapidlyadvancesinpregnancy,
menopause,stress(trauma,surgery)
–Viral:Measles

5. Van der Hoeve syndrome
Otosclerosis + osteogenesis imperfecta + blue sclera

6. Types of Otosclerosis
•Stapedial
•Cochlear
−RoundwindowandPromontory
•Mixed
−Stapedial+cochlear
•Malignant
−Rapidlyprogressingcochlearlesionwithseveresensori-
neuraldeafness

7. Types of Stapedial Otosclerosis
1. Anterior focus (commonest): 2 mm anterior to oval
window , fissula ante fenestrum, more unstable
2. Posterior focus: 2 mm behind oval window
3. Circumferential: involves footplate margin only
4. Biscuit type: footplate involved, margin is free
5. Obliterative : Obliterates the oval window completely

8. Symptoms of Otosclerosis
1. Deafness: Bilateral, slowly progressive
–Conductive: stapedial otosclerosis
–Sensorineural :cochlear otosclerosis
–Mixed :stapedial + cochlear otosclerosis
2. Soft, modulated, monotonous voice
3. Tinnitus & vertigo: in cochlear lesion

9. Symptoms of Otosclerosis contd….
4.ParacusisofWillis(ParacusisWillisii):Patienthearsbetterin
noisysurroundings(peopleincreasetheirvoiceintensityso
thatpatient’sspeechdiscriminationbecomesbetter)

10. •Otoscopy
–TympanicMembranenormalinmostcases
–Schwartzesign/Flamingopinkblush
•Pinkishcolouroverpromontory
•Seeninotospongiosis(2-10%cases)

11. Tuning Fork Tests
Rinne Weber A.B.C.
StapedialNegative
(BC > AC)
Lateralizes to
Deaf ear
Normal
CochlearPositive
(AC > BC)
Lateralizes to
Better ear
Decreased
Mixed Negative
(BC > AC)
Lateralizes to
Better ear
Decreased

12. Gelle & Bing Tests
•Vibrating tuning fork placed over mastoid
–ExternalauditorycanalisblockedinBingtest
–E.A.C. pressure increasedby Siegalization in Gelle
Bing Gelle
Otosclerosis No change No change
Normal / SNHL Intensity
Increases
Intensity
Decreases

13. Investigations
A) Pure Tone audiometry (PTA)
–Low frequency conductive deafness
–Carhart’s notch in bone conduction at 2 KHz

14. •ProposedtheoriesforCarhart’snotch
–Stapesfixationdisruptsnormalossicular
resonance(2000Hz)
–Normalcompressionmodeofboneconductionis
disturbedbecauseofrelativeperilymphimmobility
•Carhart’snotchreverseswithstapessurgery

15. B) Speech Audiometry
–Speech Discrimination Score : (maximum score
achieved) is almost 100 %
–Speech Reception Threshold (intensity at which 50
% words are heard) : increased by the amount of
conductive hearing loss

16. C) Impedance Audiometry
–As curve seen in 40 % cases
of otosclerosis (Normal middle
ear pressure but decreased
middle ear compliance)
–Others have A curve
•Stapedial reflex : absent

17. C.T. scan temporal bone
20
0
coronal oblique cuts

18. Differential Diagnosis
•Otitis Media with effusion
•Adhesive Otitis Media
•Tympanosclerosis
•Ossicular discontinuity
•Congenital ossicular chain fixation
•Malleus head fixation

19. Treatment
•No Treatment
•Hearing Aids
•Medical Treatment
•Surgical Treatment
–Stapedotomy / Stapedectomy

20. Surgical treatment of Otosclerosis

21. History of stapes surgery
•Stapes mobilization:Kessel (1880), Rosen (1952)
•Lateral semicircular canalfenestration: Holmgren
(1923), Lempert (1938)
•Stapedectomy:Jack (1893), John Shea Jr. (1956)
•Stapedotomy:Myers, 1970
•Laser Stapedotomy:Perkins, 1980

22. Inclusion criteria for stapes surgery
•Pure Tone Average between 30 -60 dB
•Air bone gap > 15 dB
•Speech discrimination score > 60 %
•Absence of sensorineural deafness

23. Contraindications for surgery
•Only hearing ear
•Meniere’s disease
•Otitis media
•Otitis externa
•Extremes of age
•Pregnancy
•Professions:divers, high construction workers,
frequent travelers, noisy surroundings

24. Surgical steps of Stapedotomy

25. Per-meatal Incision

26. Tympanomeatal flap raised

27. Bony overhang curetted

28. Chorda tympani preserved

29. Chorda tympani separated

30. Confirm footplate fixation
Checking for absence of round window reflex

31. Depth measurement prosthesis

32. Incudo -stapedial joint broken

33. Footplate perforated

34. Fenestration with burr

35. Posterior crus fractured

36. Teflon piston
•Length of piston =
medial surface of incus
to stapes footplate +
0.25 mm
•Range = 3.75 –4.25
mm
1
cm

37. Piston placed in perforation

38. Stapedius tendon cut

39. Piston crimped around incus

40. Anterior crus fractured

41. Stapes suprastructure removed

42. Footplate perforation sealed

43. Tympanomeatal flap repositioned

44. Laser Stapedotomy

45. Stapedius vaporization

46. Footplate fenestration

47. Rossette formation

48. Stapedectomy

49. Footplate Fenestration

50. Stapes suprastructure removed

51. Footplate removal

52. Prosthesis placed over Temporalis
fascia / vein graft

53. Medical Treatment
•Sodium Fluoride given in cochlear otosclerosis &
active focus of otospongiosis (Schwartze sign)
•Acts by:
a. Decreases bone resorption
b. Increases bone formation
c. Prevents enzymatic damage to cochlea
•20 mg orally, thrice daily for 3 -6 months

54. Hearing Aids
For patients
–Unfit for surgery
–Refuse surgery