ME Disorders (Otosclerosis) Flashcards
what is otosclerosis
focal disease, unique to the human temporal bone
insidious and progressive condition
There is ankylosis (fixation) of the stapes footplate to the oval window due to abnormal bony growth
what does it affect
otic capsule from where inner ear develops
what is the etiology
exact etiology is unknown but it is primarily an active remodeling process of the endochondral (results in cartilage development) layer of the temporal bone
only humans have it
true
ALL IS PROGRESSIVE UNTIL YOU DO SURGERY
TRUE
~ 70% cases are unilateral but often one ear is affected first
false, bilateral
is there normally remodeling of the otic capsule
normally once embryo period ends, no remodeling of the otic capsule and what you have is what you hav
no new bone is layed down after birth
can you have fixxation of other ossicles in otosclerosis
NO
WHEN FOOTPLATE IS FIXED INTO THE OVAL WINDOW
what is the main site of fixation
Fissula ante fenestram
what is teh Fissula ante fenestram
A minute slit like passage in the otic labyrinthine wall anterior to the oval window
anterior to oval window, when bone remodeling happens the footplate is ossified into the window
Active remodeling of this bone
otosclerosis cause
The degree of the footplate involvement in otosclerosis is
highly variable
what is the mode of transmission
ad
vertical transmission
goes from generation to generation
In the majority of cases, involvement is limited to
anterior portion of the footplate
audio we see originally
LF CHL is the result (slowly rising)
when bony fixation of the entire footplate what is audio
more flat conductive HL is observed
can you see a flat configuration?”
YES
what is obliterative otosclerosis
the bony growth may overgrow the footplate
It is not possible by audiologic testing alone to differentiate between otosclerosis of the footplate and obliterative otosclerosis
true
why is the difference between them important?
management
oto - can put in fake footplate
obl oto - chl can turn into permanent snhl
what are the sites
Obliterative otosclerosis of the round window
Cochlear otosclerosis
Histologic otosclerosis
Rare cases of ostosclerosis occurring on the round window
Obliterative otosclerosis of the round window
In rare cases, the bony growth spreads to the cochlea, the result is a progressive irreversible SNHL worse in the high frequencies
The bony growth is believed to affect the spiral ligament
The spiral ligament fibrocytes function in conjunction with the stria vascularis to mediate cochlear ion homeostasis
Cochlear otosclerosis
10 times more common than large clinical otosclerotic lesions
In this case, lesions do not encroach on stapes footplate or cochlea
They remain small and asymptomatic, discovered only incidentally on histologic examination
Histologic otosclerosis
what is the differential diagnosis of otosclerosis
osteogenesis imperfecta
what are the stages
initial - otospongeosis
intermediate
final inactive - bone stops growing and gets mineralized
primarily a disturbance of physiologic factors that normally serve to inhibit remodeling of the otic capsule
otosclerosis
Fixation of other ossicles to each other is NOT otosclerosis, instead it is called
ossicular ossification
what is mode of transmission
ad
progressive how
severity worse over time until it reaches inactive stage
usually starts as unilateral and moves bilateral
traits of ad
present in every generation
vertical transmission
complete penetrance (have the genetic predisposition but do not manifest the phenotype) & expressivity (range of severity)
how long do adults wait until getting help with their hearing
10-15 years
what could otosclerosis may be related to that is persistent in the otic capsule
measles virus
what is some evidence that supports the measles hypothesis
Measles viral-like particles found in the osteoblasts and pre-osteoblasts in active otosclerotic lesions
Measles antigen and measles virus genes have been discovered within actively growing otosclerotic lesions
Measles is a disease of humans and closely connected primates; otosclerosis occurs only in humans
A significant decline in otosclerosis was observed with the measles vaccination program
gene associated with type 1 osteogenesis imperfecta
COL1A1 gene
Type 1 osteogenesis imperfecta shares some clinical and histological similarities with
otosclerosis
_____ of all patients with type 1 osteogenesis imperfecta develop a hearing loss indistinguishable from otosclerosis
~ 50%
Some patients with ostosclerosis have _______, a feature found in almost all cases of type 1 osteogenesis imperfecta
blue sclera
what are the similarities of osteogenesis imperfecta and otosclerosis
share some clinical and histological similarities
around 50% of pts with type 1 develop HL indistinguishable from otosclerosis
blue sclera
histopathology of temporal bones is identical
both inherited as ad
Single most common cause of hearing loss in young adulthood
age
In 90% of cases, the age of onset is between
15 to 45 yrs
About _____ cases are bilateral
70%
2:1 ___ to ____ ratio
female, male
otosclerosis is most common in
white females
rare in asians and blacks
n 50% of females, initial awareness/rapid acceleration of the hearing loss occurs
during/immediately after pregnancy
what is seen on the audio for these
bilateral chl or mixed hl with rising configuration
can present unilaterally initially
50 to 60% of patients present with __________ which may indicate sensorineural involvement
roaring, hissing, or pulsatile tinnitus,
what can fluctuationsin tinnitus be caused by
related to metabolic or hormonal changes
what is paracusis willis
People with a conductive hearing loss hear better in noise than normal hearing individuals
This finding may be explained by the fact that in noise generally the intensity of conversation is louder, which makes it easy to hear
what is schwartze sign
In some cases especially younger adults, increased vascularity of the actively growing bone near the oval window is reflected through the TM as a reddish blush discoloration or glow
reddish glow to the ™
what we would see pure tone in early stag3e
Normal or mild conductive hearing loss with rising configuration
mild stage pure tone results
Conductive/mixed hearing loss with rising or flat configuration
late stage pure tone results
Flattening of the previously rising conductive or mixed hearing loss
It is not uncommon to see a mixed hearing loss especially in older adults, due to presbycusis now accompanying the long standing otosclerosis
why do we see flattening out of the rising loss in older patients?
because presbycusis is a hf sloping loss
what do you run into with bilateral chl
masking dilemma
what is carhart’s notch
BONE ONLY
at 2000 Hz, bc can be 15-20db worse than any f the other frequencies
disappearance or absent abg here
Possibly due to mechanical effects of the disease itself on the auditory system, i.e., the effect of the stapes fixation on the ME resonance
do all pt show carhart’s notch
no
only <40% of PTs
is carhart’s unique to otosclerosis
no
only present in <40%
just veause you dont have notch doesnt mean they cant have it
also see in other ossification & osteogenesis imperfecta
otosclerosis is more common than these other ones
ONLY me condition that can give you normal tymps
otosclerosis
what would immittance show
Generally normal (Jerger Type A) or As tympanogram, with low admittance and narrow gradient
Abnormal acoustic reflexes in most cases
Reduced stapes mobility, which attenuates stimulus intensity and makes acoustic reflex production difficult
Acoustic reflex decay often cannot be performed due to absence of acoustic reflexes
Tone decay is usually negative (test of retrocochlear pathology)
what would speech reveal
SRT in agreement with pta
wrs is excellent/good at suprathreshold levels
what is the clinical reason to do decay? what are you suspecting?
if you think it is a retro lesion
ALWAYS DO CONTRA DECAY - ipsi is not sensitive
what are surgical indications for otosclerosis
pre operative bone is target
need conductive componenet of at least 25dB HL bw 250-1000 hz on audiogram
The bigger the ABG gap the better the prognosis for restored hearing after surgery
true
what is the steps for surgery with bilateral otosclerosis
The poorer ear is operated on first
The second ear is operated on at least one year later if the operated ear remains stable
mri or ct for otosclerosis
ct is better for this becaues it can see the small bones
what is a negative rinne test
need - before they proceed with surgery
suggesting a conductive or mixed hearing loss (bone is better than air air)
Positive Rinne test, suggesting normal hearing or SNHL
what is surgical indication
condition that indicates you need a surgery
before surgery
what is a surgical complication
follows surgery
surgical complications
what are surgical indications
SNHL in the contralateral ear is not a contraindication to stapedectomy but does require thoughtful consideration
Cases of advanced otosclerosis are an indication for surgery
Such patients may show dramatic improvement in their speech discrimination abilities following surgery
what are conraindications to surgery
dead contralateral ear
active OM or OE or TM perf
large exostosis that can affect access to ME
what is the abs contraindication of surgery
otosclerosis may involve the endolymphatic duct resulting in S/S of Meniere’s disease
careful considerations prior to surgery to consider
Patients for whom vestibular function is critical for employment
Otologic problems in contralateral ear that may threaten hearing over time
Superior semicircular canal dehiscence (SSCD) syndrome
what is a stapedotomy
A small hole made in the stapes footplate during surgery
what is half stapedectomy
Half removal of the stapes footplate during surgery
what is total stapedectomy
Total removal of stapes footplate during surgery
A stainless steel, titanium, platinum, or teflon piston to replace the stapes footplate
prosthesis or implant used in stapes surgery
No difference in the success rate/outcome between stapedotomy vs. stapedectomy procedures
true
will you ding at air port checkpoints with this prosthesis?
no because the titanium and teflon wont make you ding
will mri effect prosthesis?
depends on the material
teflon no problem
titanium usually no problem
can be performed under local anesthesia with sedation or under general anesthesia
Stapedotomy and stapedecetomy
how long does Stapedotomy and stapedecetomy take
about 30-45 mins
laser surgery is routinely used to vaporize parts of the stapes
remainder of stapes is removed with an instrument
tCurrent prostheses are safe with lower power MRI scanners
true </= 1.5 tesla
prostheses that are compatible with MRI scanners of all strengths
Titanium, platinum, and plastic
Failure rate of surgery is about ______ %
1 to 3% (can result in a profound SNHL)
complications of surgery
WRS can worsen (up to 30%) if hearing had cochlear involvement
oval window otosclerosis
round window otosclerosis
WRS sometimes worsens (by up to 30%) if there was cochlear involvement
Stapedectomy can change a the flat mixed hearing loss to a sloping SNHL with poorer WRS
Decreased hearing at 4000 Hz is often observed post surgery
what is window otosclerosis
Otosclerosis that obliterates the oval window cannot easily be managed or removed with a laser; Other cutting instruments used
Surgery takes longer and it may be difficult to accurately assess the length of the prosthesis needed
what is round window otosclerosis
Can cause permanent conductive hearing loss
Surgical removal of otosclerosis from a completely obliterated round window universally results in SNHL and should not be attempted
what is hyperacusis
increased sensitivity to sounds; often temporary
Due to VII nerve damage during surgery – rare complication
If the facial nerve is completely filling the oval window niche, surgery may have to be aborted
facial paralysis/weakness
may have to be sacrificed due to its location
chorda tympani
what happens if damage to chorda tympani occures
Temporary decreased taste/sensation for 3 to 6 months till compensation occurs by the opposite nerve and other taste/sense nerves and mechanisms
what is perilymphatic fistual
pathologic communication between inner ear and ME
occurs at either round or oval window
can occur during early or late postoperative period
what is the result of perilymphatic fistula
Fluctuating, sudden, or progressive SNHL
Vertigo
Other symptoms include
tinnitus
disequilibrium
aural fullness
what is labyrinthitis
Vertigo during or immediately after surgery is indicative of labyrinthine insult
rare but serious
what is labyrinthitis caused by
Air or blood entering the vestibule
Mechanical trauma to the utricle, which lies in close proximity to the oval window
attributed to surgical trauma in approx 1% of cases
snhl
what can cause immediate chl during complications of surgery
Malfunction of prosthesis
Failure to recognize malleus fixation
Round window obliteration
ME effusion
Superior semicircular canal dehiscence (SSCD) syndrome
what is SSCD
The roof of the superior semicircular canal is missing
A conductive hearing loss similar to otosclerosis can be found in some patients with SSCD
Delayed-onset conductive hearing loss
duriing surgery complications
Occurs in ~ 5% of successful stapedectomies
Most common cause is erosion of long process of incus with displacement of the prosthesis
Patients with otosclerosis do well with amplification as the hearing aid provides the amplification the ME system cannot
true
what is differential diagnosis for otosclerosis
meniere’s disease
osteogenesis imperfecta
SSCD syndrom
meniere’s disease
Dizziness/vertigo (more common and of much longer duration in Meniere’s disease)
Tinnitus, which can be roaring like otosclerosis
Low frequency hearing loss, which is sensorineural in Meniere’s
SSCD syndrome
Thinning/absence of part of the bone of the semicircular canal is thought to predispose patients to this syndrome
Low frequency conductive hearing loss (250 to 1000 Hz)
how can SSCD be ruled out from being differential for otosclerosis
temporal bone CT scan
who would surgery not be an option for? they want it but they cannot?
age - older - 70-80’s, you do not recover as quickly and have other medical issues and may have chronic issues with age
health issues - dead ear on the opposite side, if you have significant autoimmune conditions, if you already have a chronic infection etc.
PT refuses surgery for any reason
