The document discusses otosclerosis, a primary metabolic bone disease that results in fixation of the ossicles and conductive hearing loss. It provides a historical overview of otosclerosis and stapes surgery, details the epidemiology and pathophysiology of otosclerosis, and describes the diagnostic evaluation, medical and surgical management options for treating otosclerosis. The surgical procedure of stapedectomy and potential complications are also outlined.

1. Otosclerosis Dr S.K. PRADHAN I.M.S.BHU

3. Introduction Otosclerosis Primary metabolic bone disease of the otic capsule and ossicles. Results in fixation of the ossicles and conductive hearing loss. May have sensorineural component if the cochlea is involved.

4. 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

5. History of Otosclerosis and Stapes Surgery Gunnar Holmgren (1923) Father of fenestration surgery Single stage technique

6. History of Otosclerosis and Stapes Surgery Julius Lempert Popularized the single staged fenestration procedure

7. History of Otosclerosis and Stapes Surgery Fenestration procedure for otosclerosis Fenestration in the horizontal canal with a tissue graft covering >2% profound SNHL Rarely complete closure of the ABG May exhibit vestibular disturbances

8. History of Otosclerosis and Stapes Surgery Samuel Rosen 1953 – first suggest mobilization of the stapes Immediate improved hearing Re-fixation

9. History of Otosclerosis and Stapes Surgery John Shea 1956 – first to perform stapedectomy Oval window vein graft Nylon prosthesis from incus to oval window

10. Epidemiology Prevalence histologic otosclerosis- 3.5% clinically significant otosclerosis- 2% Gender Histologic otosclerosis – 1:1 ratio Clinical otosclerosis – 2:1 (W:M) Possible progression during pregnancy (10%-17%) Age Most commonly-15-45 years

11. Aetiology Autosomal dominant Hereditary in 70% of cases 1% Caucasians with symptoms Autoimmune diseases Van der Hoeve syndrome Measles

12. Aetiology- Measles?

13. Pathophysiology Inciting event unknown Hereditary, endocrine, metabolic, infectious, vascular, autoimmune, hormonal Resorption and formation of new bone Limited to the temporal bone and ossicles

14. Pathology Two phases of disease Active (otospongiosis phase) Active resorption of bone Dilation of vessels Mature (sclerotic phase) Deposition of new bone (sclerotic and less dense than normal bone), Chalky white

15. Pathology Sites involved- Anterior to oval window ( Fissula ante fenestrum ) 90% Round window 30% Cochlear labyrinth 25% Stapes footplate 12% Posterior to oval window 5-10%

16. Non-clinical foci of otosclerosis

17. Anterior footplate involvement

18. Annular ligament involvement

19. Bipolar involvement of the footplate

20. Round Window

21. Biscuit footplate

22. Pathophysiology of Conductive hearing loss- oval window sclerosis. SNHL - Hyalinization of spiral ligament , toxins. Vestibular symptoms- degeneration of scarpa’s ganglion . Soluble toxic substances Direct invasion.

23. Hyalinization of the spiral ligament

24. Erosion into inner ear

27. Organ of Corti

28. Cochlear Otosclerosis Pure sensorinural hearing impairment without any conductive component. Incidence is quite low. Histiologic studies Cases of documented otosclerosis and a large sensory loss have shown large foci of otosclerosis in the otic capsule without stapes fixation.

29. Diagnosis of Otosclerosis

30. Clinical features Conductive or Mixed hearing loss Onset Slowly progressive, Bilateral (80%) Asymmetric Tinnitus (75%) Paracusis willisii Vestibular symptoms(25%)

31. History Family history 2/3 have a significant family history Prior otologic surgery History of ear infections

32. Physical Exam Pneumatic otoscopy Otomicroscopy Most helpful in ruling out other disorders Middle ear effusions Tympanosclerosis Tympanic membrane perforations Cholesteatoma or retraction pockets Schwartze’s sign Reddish hue over the promontory 10% of cases

33. Physical Exam Tuning forks Rinne- 256 Hz – negative test indicates at least a 20 dB ABG. 512 Hz – negative test indicates at least a 30 dB ABG. 1024 Hz- negative test indicates at least a 45 dB ABG Weber- ABC-

34. Differential Diagnosis Ossicular discontinuity Congenital stapes fixation Malleus head fixation Paget’s disease Osteogenesis imperfecta Adhesive otitis media

35. Audiometry Impedance Audiometry Tympanometry Acoustic Reflexes Eustachian tube function test Pure tones Audiometry

36. Tympanometry Jerger (1970) – classification of tympanograms Type A Type A Type As Type Ad Type B Type C

38. Acoustic Reflexes Otosclerosis has a predictable pattern of abnormal reflexes over time Reduced reflex amplitude Elevation of ipsilateral thresholds Elevation of contralateral thresholds Absence of reflexes

39. Pure Tone Audiometry Most useful audiometric test for otosclerosis Characterizes the severity of disease Frequency specific Low frequencies affected first(Below 1000 Hz) Air line flattens with disease progression 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

41. Imaging Computed tomography (CT) of the temporal bone Pre-op Characterize the extent of otosclerosis Severe or profound mixed hearing loss Evaluate for enlarge cochlear aqueduct Post-op prosthesis dislocation Vertigo

45. Paget’s disease

46. Management Options Medical Amplification Surgery Combinations

47. Medical Sodium Fluoride Mechanism Fluoride ion replaces hydroxyl group in bone forming fluorapatite. Resistant to resorption Increases calcification of new bone Causes maturation of active foci of otosclerosis

48. Medical Sodium Fluoride Reduces tinnitus, reverses Schwartze’s sign, resolution of otospongiosis seen on CT Dose – 20-120mg Indications Non-surgical candidates Surgical candidates with + Schwartze’s sign Treat for 6 months pre-op Hearing results 50% stabilize 30% improve Re-evaluate for 2 yrs with CT and for Schwartze’s sign to resolve

49. Medical Bisphosphonates Inhibits bone resorption by inhibiting osteoclastic activity. Often supplement with Vitamin D and Calcium. Studies conducted on otosclerosis patients with neurotologic symptoms report the majority of patients with subjective improvement or resolution.

50. Amplification Conventional hearing aids Bone-anchored hearing aids

51. Surgery Best surgical candidate Air conduction level 45 – 65 dB Bone conduction level 0 – 25 dB Air-Bone Gap 15 dB Discrimination score >60% Factors affecting stapes surgery Audiometric profile Skill of the surgeon Facilities Medical condition of the patient

52. Surgery Other factors Age of the patient Elderly Congenital stapes fixation (44% success rate) Occupation Diver, Pilot Vestibular symptoms Meniere's disease Concomitant otologic disease Cholesteatoma

53. Canal Injection 2-3 cc of 2% lidocaine with 1:100,000 epinephrine 4 quadrants Bony cartilaginous junction

54. Raise Tympanomeatal Flap 6 and 12 o’clock positions 6-8 mm lateral to the annulus Take into account curettage of the scutum

55. Separation of chorda tympani nerve from malleus Separate the chorda from the medial surface of the malleus to gain slack Avoid stretching the nerve Cut the nerve rather than stretch it

56. Curettage of Scutum Curettage a trough lateral to the scutum, thinning it Then remove the scutum (incus to the round window)

57. Middle ear examination Mobility of ossicles Confirm stapes fixation Evaluate for malleus or incus fixation Abnormal anatomy Dehiscent facial nerve Overhanging facial nerve Deep narrow oval window niche Ossicular abnormalities

59. Measurement for prosthesis Measurement Lateral aspect of the long process of the incus to the footplate

60. Drill Fenestration 0.7mm diamond burr Motion of the burr removes bone dust Avoids smoke production Avoids surrounding heat production

61. Laser Fenestration First laser stapedotomy performed by Perkins in 1978 Less trauma to the vestibule Less incidence of prosthesis migration Less fixation of prosthesis by scar tissue TYPES - Argon and Potassium titanyl phosphate (KTP) Wave length 500 nm Surgical and aiming beam Carbon dioxide (CO2) 10,000 nm Ill defined fuzzy beam

62. Stapedotomy

63. Oval window seal Vein (hand or wrist) Temporalis fascia Blood Fat Tragal perichondrium Gelfoam (now discouraged)

64. Total Stapedectomy Indications Extensive fixation of the footplate Floating footplate Disadvantages Increased post-op vestibular symptoms More technically difficult Increased potential for prosthesis migration

69. Reconstructing the annular ligament

70. Stapedectomy vs. Stapedotomy Better low frequency hearing gain. Better high frequency hearing gain. Decreased perilymphatic fistula. Decreased SNHL Decreased Vertigo

71. Postoperative Water precautions No valsalva Post-op audio

72. Special Considerations and Complications in Stapes Surgery

73. Overhanging Facial Nerve Usually dehiscent(10%) Consider aborting the procedure Facial nerve displacement (Perkins, 2001) Facial nerve is compressed superiorly with No. 24 suction (5 second periods) 10-15 sec delay between compressions Perkins describes laser stapedotomy while nerve is compressed

74. Floating Footplate Footplate dislodges from the surrounding OW niche Incidental finding More commonly iatrogenic Prevention Laser Management Abort total stapedectomy

75. Diffuse Obliterative Otosclerosis Occurs when the footplate, annular ligament, and oval window niche are involved Closure of air-bone gap < 10 dB less common. Refixation commonly occurs

76. Perilymphatic Gusher Associated with patent cochlear aqueduct Increased incidence with congenital stapes fixation Increases risk of SNHL Management Rapid placement of the OW seal then the prosthesis Bed rest, avoid Valsalva .

77. SNHL 1%-3% incidence of profound permanent SNHL Temporary Serous labyrinthitis Reparative granuloma Permanent Suppurative labyrinthitis Extensive drilling Basilar membrane breaks Vascular compromise

78. Reparative Granuloma Granuloma formation around the prosthesis and incus 2 -3 weeks post-op Initial good hearing results followed by an increase in the high frequency bone line thresholds Associated tinnitus and vertigo Exam – reddish discoloration of the posterior TM Treatment ME exploration Removal of granuloma Prognosis – Return of hearing with early excision

79. Vertigo Most commonly short lived (2-3 days) More prolonged after stapedectomy compared to stapedotomy Due to serous labyrinthitis Medialization of the prosthesis into the vestibule With or without perilymphatic fistula Reparative granuloma

81. Recurrent Conductive Hearing Loss Slippage or displacement of the prosthesis Most common cause of failure Immediate Technique Trauma Delayed Slippage from incus narrowing or erosion Adherence to edge of OW niche Stapes re-fixation Malleus or incus ankylosis

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