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Abstract
Otosclerosis is a common bone disorder of the otic capsule, unique to the endochondrial layer of the temporal bone and known to affect human beings only.
Clinical otosclerosis has a prevalence of 0.2-1% among white adults, making it the single most common cause of hearing impairment in this age group. About 8-10% of Caucasian adult temporal bones have histological foci of otosclerotic lesions.
Although encountered in all age groups, usually the clinical presentation occurs between the second and fifth decades of life. Uncommonly children and adolescents may also have conductive hearing loss caused by otosclerosis.
The aetiology of the disease is unknown, but epidemiological studies indicate the involvement of genetic as well as environmental factors. Various etiopathogenetic hypotheses have been proposed. The major hypotheses are genetic factors, immunologic factors, and viral infection.
The gene for otosclerosis has not been clearly identified, but otosclerosis was linked to 8 otosclerotic loci. Other studies have related otosclerosis to the COL1A1 gene, which encodes for type 1 collagen.
Recent investigations on the role of infectious agents have implicated the measles virus as having, at least, an inciting role in patients with a genetic predisposition for otosclerosis. However, the actual role of the virus in producing the disease is not established.
Its clinical manifestations are primarily conductive hearing loss (CHL), although sensorineural hearing loss (SNHL) and mixed hearing loss can also occur. Some patients report improved speech understanding in a noisy environment (known as paracusis of Willis). Tinnitus is the second most common complaint reported. Vestibular symptoms are not uncommon.
Medical management of otosclerosis remains controversial and is primarily directed at maturing the involved bone and decreasing osteoclastic activity. Hearing aids, however, do offer an effective means of non surgical management of hearing loss in otosclerosis.
Stapes surgery for correction of conductive hearing loss in adults with otosclerosis is a well-established procedure.
The aim of this work is to evaluate of stapedectomy operation in children and adults and to study the proposed association of otosclerosis with Sp1 binding site polymorphism in COL1A1.