Friday, 4 March 2016

Otosclerosis


The cochlear promontory may have a faint pink tinge reflecting the vascularity of the lesion, referred to as the Schwartz sign. Conductive hearing loss is usually secondary to impingement of abnormal bone on the stapes footplate. This involvement of the oval window forms the basis of the name fenestral otosclerosis. The most common location of involvement of otosclerosis is the bone just anterior to the oval window at a small cleft known as the fissula ante fenestram.
Also there is mounting evidence that measles virus is present within the otosclerotic foci, implicating an infectious etiology (this has also been noted in Paget’s Disease).
Otosclerosis is associated with osteogenesis imperfecta in 0.15 % of cases. This is known as Van der Hoeve syndrome or Adair - Dighton syndrome.
....### cochlear implants. ....
Inserted in scala tympani
Inserted via round window
*External device: Processor, Microphone ,Transmitter.
*Internal device :Receiver, stimulator.
Lowest age 1 yr

##### types of hemorrhage
primary - at the time of operation
reactionary - within 24 hours of surgery
secondary - 5th to 10th post operative day ..

The classification system for tympanograms commonly used today was developed by Liden (1969) and Jerger (1970). There are three main types of tympanograms: A, B, and C. Type A tympanograms look like a teepee, and indicate a normal middle ear system, free of fluid or physiological anomalies which would prevent the admittance of sound from the middle ear into the cochlea.
Type B tympanograms are a flat line, which is consistent with middle ear pathology, such as fluid or infection behind the ear drum. In some cases, these tympanograms are seen when there is a hole in the ear drum; the difference lies in the ear canal volume: a larger ear canal volume indicates a perforation in the ear drum.
Type C tympanograms are still shaped like a teepee, but are shifted negatively on the graph. This indicates negative pressure in the middle ear space, often consistent with sinus or allergy congestion, or the end-stages of a cold or ear infection.

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