复旦大学：《耳鼻咽喉科学》课程教学资源（PPT课件讲稿，英文版）Otosclerosis

Otosclerosis Chunfu dai Otolaryngology Department Fudan University

Otosclerosis Chunfu Dai Otolaryngology Department Fudan University

Background Definition primary metabolic bone disease of the otic capsule and ossicles It causes fixation of the ossicles(stapes u It results in conductive or mixed hearing loss It is genetically-mediated via autosomal dominant transmission

Background ◼ Definition ◼ primary metabolic bone disease of the otic capsule and ossicles ◼ It causes fixation of the ossicles (stapes) ◼ It results in conductive or mixed hearing loss. ◼ It is genetically-mediated via autosomal dominant transmission

Epidemiology Ra ace incidence of microscopic otosclerosis Caucasian 10% Asian 5% African american 1% Native american 0

Epidemiology Race incidence of microscopic otosclerosis Caucasian 10% Asian 5% African American 1% Native American 0%

Epidemiology Sex variation(M: F=1: 2.5) u Women more commonly seek medical attention for hearing loss secondary to otosclerosis histologic studies prevalence of otosclerosis show no difference in men versus women

Epidemiology ◼ Sex variation (M:F=1:2.5) ◼ Women more commonly seek medical attention for hearing loss secondary to otosclerosis, ◼ histologic studies prevalence of otosclerosis show no difference in men versus women

Epidemiology Age The incidence of otosclerosis increases with age. u The most common age group presenting with hearing loss from otosclerosis is 15-45 years, s however it has been reported to manifest as early as 7 years and as late as the mid 50s

Epidemiology ◼ Age ◼ The incidence of otosclerosis increases with age. ◼ The most common age group presenting with hearing loss from otosclerosis is 15-45 years, ◼ however it has been reported to manifest as early as 7 years and as late as the mid 50s

Etiology Many theories have been proposed such as hereditary, 54% of patients present with family history endocrine, women with pregnancy worse her hearing metabolic, enzyme abnormal was pathogen infectious, virus was identified in the lesion a vascular autoimmune J none have be proven, Hormonal factors have been suggested to play a role in otosclerosis based on the observation that pregnancy sometimes accelerates the progression of the disease

Etiology ◼ Many theories have been proposed such as ◼ hereditary, 54% of patients present with family history ◼ endocrine, women with pregnancy worse her hearing ◼ metabolic, enzyme abnormal was pathogen ◼ infectious, virus was identified in the lesion ◼ vascular, ◼ autoimmune, ◼ none have be proven. Hormonal factors have been suggested to play a role in otosclerosis based on the observation that pregnancy sometimes accelerates the progression of the disease

Pathophysiology Otosclerosis( otospongiosis) is an osseous dyscrasia, limited to the temporal bone, and characterized by resorption and formation of new bone in the area of the ossicles and otic capsule

Pathophysiology ◼ Otosclerosis (otospongiosis) is an osseous dyscrasia, limited to the temporal bone, and characterized by resorption and formation of new bone in the area of the ossicles and otic capsule

Pathophysiology The most common site of involvement is the anterior oval window near the fistula ante fenestrum When both the anterior and posterior ends of the footplate are involved it is termed"bipolar"involvement or fixation(if the footplate is immobile) f only the footplate is involved, it is sometimes referred to as a " stapedial otosclerosis When the entire footplate and annular ligament are involved it is known as an obliterated footplate or obliterative otosclerosis The round window is involved in approximately 30% to 50% of cases

Pathophysiology ◼ The most common site of involvement is the anterior oval window near the fistula ante fenestrum. ◼ When both the anterior and posterior ends of the footplate are involved it is termed “bipolar” involvement or fixation (if the footplate is immobile). ◼ If only the footplate is involved, it is sometimes referred to as a “stapedial otosclerosis”. ◼ When the entire footplate and annular ligament are involved it is known as an obliterated footplate or obliterative otosclerosis. ◼ The round window is involved in approximately 30% to 50% of cases

Pathophysiology otosclerosis has two main forms. an early of spongiotic phase(otospongiosis) The early phase is characterized by multiple active cell groups including osteocytes, osteoblasts, and histiocytes. It develops a spongy appearance because of vascular dilation secondary to osteocyte resorption of bone surrounding blood vessels. This can be seen grossly as red hue behind the tympanic membrane termed Schwartze's sign

Pathophysiology ◼ otosclerosis has two main forms: ◼ an early of spongiotic phase (otospongiosis) ◼ The early phase is characterized by multiple active cell groups including osteocytes, osteoblasts, and histiocytes. It develops a spongy appearance because of vascular dilation secondary to osteocyte resorption of bone surrounding blood vessels. This can be seen grossly as red hue behind the tympanic membrane termed “Schwartze's sign

Pathophysiology otosclerosis has two main forms u a late or sclerotic phase a dense sclerotic bone forms in the areas of previous resorption. Both the sclerotic and spongiotic as well as intermediate phases may be present at the same time. Otosclerotic foci always begin in endochondral bone but may progress to involve endosteal and periosteal layers and even enter into the membranous labyrinth

Pathophysiology ◼ otosclerosis has two main forms ◼ a late or sclerotic phase ◼ dense sclerotic bone forms in the areas of previous resorption. Both the sclerotic and spongiotic as well as intermediate phases may be present at the same time. Otosclerotic foci always begin in endochondral bone but may progress to involve endosteal and periosteal layers and even enter into the membranous labyrinth