14. Fixations of auditory chain, tympanosclerosis, otosclerosis. Clinic, diagnosis, treatment.

What are the causes of the fixation of the different ossicles

• Malleus

  • tympanosclerosis

  • chronic otitis media

  • congenital fixation

• incus

  • chronic middle ear disease

  • cholesteatoma

• stapes

  • otosclerosis

Define tympanosclerosis

• hyalinisation and calcification of subepithelial CT of tympanic membrane and middle ear → ossicular fixation → CHL

What is the etiology of tympanosclerosis

• chronic otitis media

• insertion of tympanostomy tube- especially if aspiration is performed

• atherosclerosis

What is the pathology of tympanosclerosis

• progressive metaplasia of middle ear mucosa and TM membrane

• → fibrosis, sclerosis, formation of cholesterol granulomas

How do you diagnose tympanosclerosis

• history

• audiometry → CHL

• otoscopy → white, chalky patches on tympanic membrane

What is the treatment of tympanosclerosis

• hearing aid

• surgery

  • excision of sclerotic area and repair of ossicular chain

    • strong tendency to recur after surgical treatment

Define otosclerosis

• abnormal growth of body labyrinth capsule

• occurs when stapes fuses to oval window- cannot vibrate → CHL

What is the etiology of otosclerosis

• endocrinological changes and bone growth abnrmalities

• environmental → measles

• hereditary

What is the epidemiology of otosclerosis

• between 15-50 → 2nd most common cause of CHL in this age

• progresses during pregnancy- hormone response

How do you diagnose otosclerosis

• history, imaging- HRCT

• otoscopy

  • TM normal + pink blush (Schwart’z sign) due to neovascularisation of otosclerotic bone

• tympanometry → type A curve with decreased amplitude

• hearing tests

  • PTA

  • Gelle test negative

What is the treatment of otosclerosis

• surgery → stapedectomy or stapedotomy with prosthesis

• if cochlear involvement → oral sodium fluoride to halt progression of inner ear changes

• hearing aid