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
