Otosclerosis

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Otosclerosis

  1. 1. OTOSCLEROSIS <ul><li>Lecture </li></ul><ul><li>BY </li></ul><ul><li>Dr Mazhar Iftikhar </li></ul>
  2. 2. Anatomy <ul><li>Otic Labyrinth </li></ul><ul><li>Periotic Labyrinth </li></ul><ul><li>Otic Capsule </li></ul>
  3. 5. Definition <ul><li>Primary localized disease of bony otic capsule </li></ul><ul><li>Irregular spongy bone replaces dense enchondral bone </li></ul><ul><li>Characterised by; </li></ul><ul><ul><li>Spongy bone </li></ul></ul><ul><ul><li>Hearing loss </li></ul></ul>
  4. 6. Aetiology <ul><li>Anatomical basis </li></ul><ul><li>Hereditary 50% </li></ul><ul><li>Race white> negroes </li></ul><ul><li>Sex females> males </li></ul><ul><li>Age of onset 20 - 30 </li></ul><ul><li>Autoimmune type II collagen </li></ul><ul><li>Measles virus antibodies </li></ul>
  5. 7. Incidence <ul><li>Clinical otosclerosis upto 3.5% </li></ul><ul><li>Histological otosclerosis upto 13% </li></ul>
  6. 8. Pathology <ul><li>Grossly; </li></ul><ul><ul><li>Chalky white </li></ul></ul><ul><ul><li>May be Red /inc vascularity </li></ul></ul><ul><ul><li>Spongy bone </li></ul></ul>
  7. 9. Histopathology <ul><li>Globuli Interossei </li></ul><ul><li>Areas of; </li></ul><ul><ul><li>Bone resorption </li></ul></ul><ul><ul><li>New bone formation </li></ul></ul><ul><ul><li>Vascular proliferation </li></ul></ul><ul><ul><li>Connective tissue stroma </li></ul></ul><ul><li>Spongiotic bone </li></ul>
  8. 10. Distribution of lesion <ul><li>Anterior to oval window 90% </li></ul><ul><li>Round window 30% </li></ul><ul><li>Cochlear labyrinth 25% </li></ul><ul><li>Stapes footplate 12% </li></ul><ul><li>Posterior to oval window 5-10% </li></ul>
  9. 12. Pathology of CHL <ul><li>Conductive hearing loss </li></ul><ul><ul><li>5-60 dB </li></ul></ul><ul><li>Expansion to ant of oval window 30-40dB </li></ul><ul><li>Bony ankylosis >40dB </li></ul><ul><li>Narrowing & impairment of annular lig at post stapediovestibular joint </li></ul>
  10. 14. Pathology of SNHL <ul><li>Subject of much controversy </li></ul><ul><li>Atrophy / Hylinization of spiral ligament </li></ul><ul><li>cytokines </li></ul>
  11. 16. Pathology of vestibular symptoms <ul><li>Scarpa’s ganglion </li></ul><ul><li>Soluble toxic substances </li></ul><ul><li>Direct invasion </li></ul>
  12. 17. Symptomatology <ul><li>Slowly progressive hearing loss </li></ul><ul><ul><li>Apparent at 25 – 30 dB loss </li></ul></ul><ul><li>Paracusis Willisii </li></ul><ul><li>Characteristic soft speech </li></ul><ul><li>Tinnitis </li></ul><ul><li>Dizziness & vertigo rarely </li></ul>
  13. 18. Physical Exam <ul><li>Careful Otoscopic Exam </li></ul><ul><li>Microscopic Exam </li></ul><ul><ul><li>Rule out other causes </li></ul></ul><ul><ul><li>Tympanic memb normal </li></ul></ul><ul><ul><li>Middle ear pneumatized </li></ul></ul><ul><ul><li>Reddish blush (schwartze sign ) </li></ul></ul>
  14. 19. Classic Audiometric Findings <ul><li>Negative Rinne test </li></ul><ul><li>Low frequency CHL </li></ul><ul><li>Carhart notch </li></ul><ul><li>Type A/As tympanogram </li></ul><ul><li>Diphasic or absent reflexes </li></ul>
  15. 22. Imaging Studies <ul><li>CT Scanning </li></ul><ul><li>MRI </li></ul>
  16. 24. Treatment
  17. 25. A. Observation <ul><li>Least risky </li></ul><ul><li>Least expensive </li></ul><ul><li>When no intervention recquired </li></ul><ul><li>Audiogram on yearly basis </li></ul>
  18. 26. B. Nonsurgical Measures. <ul><li>1. Sodium Flouride Therapy </li></ul><ul><ul><li>Reduces bone resorption </li></ul></ul><ul><ul><li>Inc bone formation </li></ul></ul><ul><ul><li>Inhibit proteolytic enzymes </li></ul></ul><ul><li>2. Bisphosphonates </li></ul><ul><ul><li>Anti resorptive/inhibit osteoclasts </li></ul></ul>
  19. 27. B. Nonsurgical Measures <ul><li>3. Amplification </li></ul><ul><ul><li>Conventional hearing aid </li></ul></ul><ul><ul><li>Bone-anchored hearing aids </li></ul></ul>
  20. 28. C. Surgical Measures <ul><li>Indications </li></ul><ul><ul><li>Air conduction level 45 – 65 dB </li></ul></ul><ul><ul><li>Bone conduction level 0 – 25 dB </li></ul></ul><ul><ul><li>Air-Bone Gap 15 dB </li></ul></ul><ul><ul><li>Discrimination score >60% </li></ul></ul>
  21. 30. Surgical technique <ul><li>Anaesthesia </li></ul><ul><li>Tympanomeatal flap raised </li></ul><ul><li>Ossicular chain inspected & palpated </li></ul><ul><li>Divisionh of stapedius tendon </li></ul><ul><li>Crurectomy </li></ul><ul><li>Stapedotomy </li></ul><ul><li>Insertion of prothesis & packing </li></ul>
  22. 32. Recent Advances <ul><li>LASER use </li></ul><ul><li>Cochlear Implantation </li></ul>
  23. 33. Revision Surgery <ul><li>Encourage to use hearing aids </li></ul><ul><li>Failure may be due to </li></ul><ul><ul><li>Incus erosion </li></ul></ul><ul><ul><li>Poorly positioned prosthesis </li></ul></ul><ul><ul><li>Mallius or Incus fixation </li></ul></ul><ul><ul><li>Reobliteration </li></ul></ul>
  24. 35. Prognosis <ul><li>Immediate success </li></ul><ul><li>Decline slowly </li></ul><ul><li>After Stapedotomy 3dB decline per decade </li></ul><ul><li>After stapedectomy 9dB decline per decade </li></ul>

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