Otosclerosis

ENT

1. Otosclerosis Mr. Binu Babu M.Sc. Nursing Mrs. Jincy Ealias M.Sc. Nursing

2. Otosclerosis is the “hardening of the ear” results from abnormal bone growth in the middle ear that cause hearing loss. Otosclerosis is a disease of otic capsule in which new vascular spongy bone formation causes ankylosis or fixation of the foot plate of the stapes and results in progressive conductive hearing loss. Usually begin in one ear but may eventually affect both ears.

3. ETIOLOGY  Exact cause not known . Heredity : Family history of deafness is present in 50% of cases. Sex : females are affected twice as often as males. Age of onset: usually occurs between 20-30 years of age. Pregnancy : Otosclerosis may be initiated or aggravated by pregnancy but never caused by it . Other factors : Metabolic disorder Endocrinal disorder Focal infection Viral infection - measles

4. Types

5. Clinical Otosclerosis Two sub types Stapedial Otosclerosis : it causes stapes fixation and results conductive deafness Cochlear Otosclerosis : it involves region of round window and may cause senso -neural hearing loss due to liberation of toxic materials. Histological Otosclerosis :  remains asymptomatic and cause neither conductive nor senso -neural hearing loss, but is revealed only at postmortem

6. Stages Early or spongiotic phase ( otospongiosis ) Late or sclerotic phase

7. Early or spongiotic phase ( otospongiosis ) Osteolytic resorption of bone develops a spongy appearance. It causes vascular dilation bone surrounding blood vessels. This can be seen grossly as red hue behind the tympanic membrane termed “ Schwartze's sign”.

8. Late or sclerotic phase Dense sclerotic bone forms in the areas of previous resorption.

9. Pathophysiology Normal bone is absorbed and replaced by vascular spongy osteoid tissue Bone become thicker and less vascular Fixes the stapes Prevents vibration of ear bones in response to sound waves Conductive deafness Spread to foot plates of stapes Affect bony capsule of the labyrinth Results in sensory neural deafness

10. Clinical features Slowly progressive, bilateral (80%), asymmetric, hearing loss Tinnitus (ringing in the ear) Vertigo Dizziness

11. Diagnostic measures History collection Physical examination Rinne test- Bone conduction is better than air conduction Weber test- laterization to affected ear  Audiogram : to confirm hearing loss Otoscopic examination : revels normal tympanic membrane or Schwartze sign is observed in 10% of patients. 

12. Management No known nonsurgical treatment for otosclerosis . The use of sodium fluoride can mature the abnormal spongy bone growth and prevent the breakdown of the bone tissue. Sodium fluoride for 2 years, with calcium , arrests the rapid progress of otosclerosis . ( Fluoride ion replaces hydroxyl group in bone forming fluorapatite . It resistant to resorption. It increases calcification of new bone and causes maturation of active foci of otosclerosis ) Hearing aid if needed

13. Surgical Management Stapedectomy : A stapedectomy involves removing the stapes superstructure and part of the footplate and inserting a tissue graft and a suitable prosthesis. The prosthesis bridges the gap between the incus and the inner ear, providing better sound conduction.

14. Stapedotomy Performed by drilling a small hole in the stapes footplate with micro drill or laser, and the insertion of a piston like prosthesis.

15. Post operative management Operated ear upside for 24 hrs after surgery. Monitor vital signs Observe for bleeding or drainage. Caution in ambulation: as dizziness may occur  Antibiotic & Analgesic: to control infection & pain Medicated ribbon gauze pack removed after 5-7 days 

16. Patient education Balance disturbance or true vertigo may occur during the postoperative period for several days. Avoid sudden movements. hearing may fade the first few weeks after surgery because of the blood clot that forms in the ear canal. As the clot shrinks, hearing will gradually improve. Do not lie on operated ear Do not blow the nose Cough or sneeze with mouth open to reduce pressure on the ear No heavy lifting for at least 2 weeks Avoid water entry into ear for 2 months.