Week 6: Cholesteatoma & Otosclerosis Flashcards
Primary acquired cholesteatoma develops b/c of ___, which causes a retraction of the TM, most frequently in the pars flaccida.
Primary acquired cholesteatoma develops b/c of negative middle ear pressure , which causes a retraction of the TM, most frequently in the pars flaccida.
Secondary acquired cholesteatoma develops b/c of ____ such as with pressure equalization tube placement or trauma.
Secondary acquired cholesteatoma develops b/c of epithelial cells being introduced into the middle ear such as with pressure equalization tube placement or trauma.
Otitis hydrocephalus is most likely caused by what?
Extension of infection (typically from chronic otitis media) into the sigmoid sinus through bony erosion/dehiscence, and can lead to thrombophlebitis.
This impairs venous outflow through the sigmoid sinus and leads to intracranial HTN.
Which bone is most commonly eroded by cholesteatoma
Incus.
(The malleus often gets displaced in cases of early cholesteatoma w/widening of Prussak’s space)
Cholesteatomas are ___ on T1 and ___ on T2
Cholesteatomas are hypointense on T1 and hyperintense on T2
Meningiomas are ___ on T1 and T2.
Meningiomas are isointense on T1 and T2.
Cholesterol granulomas are ___ on T1 and T2.
Cholesterol granulomas are hyperintense on T1 and T2.
(A and B in the figure)
Schwannomas are ___ on T1 and T2 w/foci of high intensity on T2.
Schwannomas are Isointense on T1 and T2 w/foci of high intensity on T2.
(A = T1, B = T2)
Within the IAC, the FN is found ___ to the cochlear nerve
Above
(“7UP C8ke down”)
At the first genu, the tympanic segment of the FN runs parallel and superior to the ____and just superior to the ____.
At the first genu, the tympanic segment of the FN runs parallel and superior to the cochleariform process and just superior to the oval window.
A bluish coloration underlying cholesteatoma matrix may indicate a ___,
Underlying fistula (and thus increased risk of SNHL)
See question in image.
Otosclerosis.
This patient shows a mixed HL in R ear w/a gap between air and bone conduction, indicating conductive hearing loss, which closes at 2,000 Hz, known as “Carhart’s notch.”
This is an artificial drop in the bone line due to disruption of ossicular resonance.
A labyrinthine fistula is an erosive loss of _____ and is almost exclusively caused by cholesteatoma.
A labyrinthine fistula is an erosive loss of endochondral bone w/o loss of perilymph and is almost exclusively caused by cholesteatoma.
A labyrinthine fistula is an erosive loss of endochondral bone w/o loss of perilymph and is almost exclusively caused by ___.
A labyrinthine fistula is an erosive loss of endochondral bone w/o loss of perilymph and is almost exclusively caused by cholesteatoma.
Most labyrinthine fistulas involve the ___.
Most labyrinthine fistulas involve the horizontal SCC, rarely erosive into the superior SCC, posterior SCC, cochlea, and/or vestibule.
2/3rds of middle ear congenital cholesteatomas are seen as a white mass in the ___.
2/3rds of middle ear congenital cholesteatomas are seen as a white mass in the anterior-superior quadrant.
Congenital cholesteatomas may also be found within the ___ and ___.
They do not tend to cause a CHL until they are big enough to interfere with or begin to erode w/the ossicles.
Congenital cholesteatomas may also be found within the TM and petrous apex.
They do not tend to cause a CHL until they are big enough to interfere with or begin to erode w/the ossicles.
Blunting of the scutum seen on CT scan is often a sign of ___.
Blunting of the scutum seen on CT scan is often a sign of cholesteatoma.
Epitympanum cholesteatomas originate in the shallow pocket that is ____, which lies between he pars flaccida (or scutum) and the neck of the malleus.
Epitympanum cholesteatomas originate in the shallow pocket that is Prussak space, which lies between he pars flaccida (or scutum) and the neck of the malleus.
Cholesteatomas most commonly exit Prussak space by the _____ route and penetrates the superior incudal space (lateral to the body of the incus), then —> transverse the aditus ad antrum to enter the mastoid antrum.
Cholesteatomas most commonly exit Prussak space by the posterior route and penetrates the superior incudal space (lateral to the body of the incus) —> transverse the aditus ad antrum to enter the mastoid antrum.
____ approaches have been shown to be well-suited for drainage of cholesterol granulomas that abut the sphenoid sinus.
Endoscopic trans-sphenoidal approaches have been shown to be well-suited for drainage of cholesterol granulomas that abut the sphenoid sinus.
(Trans-sphenoidal approaches also allow for simultaneous placement of a drain into the sinonasal cavity).
Which section of the ossicular chain has the most fragile blood supply and is the most susceptible to necrosis?
Long process of the incus.
(blood supply to the long process of the incus is adequate in healthy individuals. due to its more tenuous blood supply it is often necrosed in patients w/cholesteatomas)
Where is the most common site of involvement of otosclerosis?
Anterior crura (fissula ante fenestrum) of the Stapes footplate.
Otosclerosis can present as a SNHL if the _______________.
Otospongiotic process is primarily around the cochlea rather then around the ossicles.
