Otology Flashcards
How many hours of 85 dB noise can someone experience at the workplace?
16
How many hours of 90 dB noise can someone experience at workplace?
8
How many hours of 92 dB noise can someone experience at workplace?
6
How many hours of 95 dB noise can someone experience at workplace?
4
How many hours of 100 dB noise can someone experience at workplace?
2
How many hours of 105 dB noise can someone experience at workplace?
1
How many hours of 110 dB noise can someone experience at workplace?
.5
How many hours of 115 dB noise can someone experience at workplace?
.25
At what age can u get an ABI
12
What chromosome is the NF1 gene located on
17
What chromosome is NF2 located on
22
What portion of bony labyrinth is taken up by membranous labyrinth?
25%
Carboplatinum is toxic to which structure in ear
Inner hair cells
Cisplatin is toxic where?
Stria vascularis Spiral ganglion cells Outer hair cells
What is Alexander aplasia
Cochlear duct differentiation at the level of the nasal coil is limited leading to effects on organ of Corti and ganglion cells
Mondini aplasia
Only basal coil of cochlea can be identified
What is scheibe aplasia
Malformation of membranous labyrinth in cochlea and saccule
Michel aplasia
Complete age new is of petrified portion of temporal bone
Which ear is more commonly affected in microtia
Right
What structure receives the crura of the semicircular canals
Utricle
What is the jahrsdoerfer scoring system
Scoring of how good a candidate is for aural atresia repair. 6-8 poor candidate, 8-10 moderate, 10 and up great candidate
What is the most common complication of Cholesteatoma
Labyrinthine fistula
Which nerve supplies sensory innervation to the conchal bowl?
Nervus intermedius, branch of facial
What percent of cochlear afferents originate from outer hair cells
5-10%
What percent of cochlear afferents originate from inner hair cells
90-95%
What is the olivocochlear bundle
Carries deferents that regulate cochlear gain and frequency selectivity of the outer hair cells
What inner ear structure terminates at the round window?
Scala tympani
What is dorello’s canal
between the petrous tip and the sphenoid bone. It is the groove for the VI nerve, why you get abducens palsy and pain behind the eye in gradenigo syndrome
What is one way that otosclerosis can cause SNHL within cochlea?
Hyalinization of the stria vascularis causing difficulty with recycling potassium ions
What is the difference between an osteoma and an exostosis?
osteoma -> narrow base, easy to remove exostosis -> broad base, lamellar bone formation, must be drilled
What decibel gain does the tortuosity of the EAC provide?
10-15 dB
What is the dB gain of the middle ear?
27.5 dB (gain from ossicular chain (2.5) and TM (25), added together)
What is the ratio of the length of the manubrium to long process of incus and what does this add to the gain?
1.3: 1 -> 2.5 dB
What is the ratio of the area of the pars tensa to the size of the oval window and what does this add to the gain?
55 mm: 3.2 mm, or 17:1 resulting in 25 dB gain
Up to what size of vestibular schwannoma can you use gamma knife radiation?
UP to 3 cm, larger than that and the tumor can swell causing hydrocephalus
what does cVEMP test?
The saccule and subsequently inferior vestibular nerve
oVEMP tests what?
The utricle, or superior vestibular nerve
which is the most vestibulotoxic antibiotic?
streptomycin, then gentamicin
For what age are ABIs approved in children?
12
What percent ototoxicity is aminoglycosides
10%
what kind of granuloma forms in langherhans hictiocytosis
eosinophilic
What age range do you do behavioral observational audiometry?
0-6 months
What age range do you do visual reinforcement audiometry?
6 months to 2 years
What age range do you do conditioned play audiometry?
2 - 6 years
Describe what weeks different cochlear anomalies arise
Cochlear anomalies ° Common cavity: fourth week ° Cochlear aplasia: fifth week ° Cochlear hypoplasia: sixth week ° Incomplete cochlear partitions (“Mondini malformation”): seventh week
Which SCC develops last and thus displays the most anomalies
LSCC
What space is located anterior to the cog in the middle ear?
supratubal recess
pathway of Vemp testing
acoustic stimulus -> saccule -> inferior vestibular nerve -> brainstem vestibular nucleus -> spinal tract -> scm
What is this a picture of
cvemp
Why is VEMP testing useful in vestibular schwannomas?
If VEMP absent, then likely tumor is arising from the inferior vestibular nerve, which is closest to the cochlear nerve, therefore hearing preseration is LESS likely with surgery
What is calorics testing?
Horizontal/lateral canal, innervated by the superior vestibular nerve
what is depicted in this image
Calorics, Weakness in left lateral SCC (superior vestibular nerve)
Abnormalities in saccadic testing are indications of what kind of problems?
CEntral problems, like neurodegenerative not peripheral vestibular system
What does it mean when the tracking tests are abnormal
CNS issue
What 3 components are the rotary chair tests testing?
What is it useful for checking?
Phase, Gain, Asymmetry
Confirmation of caloric testing
Checking for compensation
Checking bilateral losses
What is displayed in this image
Rotary chair testing, normal
What are the two components of posturography testing
Sensory organization test
Movement coordination test
What is the normal interaural attenuation for bone conduction?
0dB
What does the utricle sense
Horizontal linear acceleration
What does the saccule sense
vertical linear acceleration
What is Ewald’s law
Describes the push pull system of the vestibular system
How are the kinocilia oriented in the lateral canal?
Kinocilia oriented in such a way that ampulopedal flow stimulates
How are kinocilia oriented in the superior and posterior canals
Kinocilia oriented in such a way that ampullofugal flow stimulates
What do you see on the ECOG in menieres?
Increased sp/ap ratio (>0.4)
Where is the dehiscence of SSCD located
anterior an opposite to superior petrosal sinus
How does cholesteatoma get from epitympanum to mesotympanum if it is of epitympanic origin
Extends through the posterior pouch of Von Trolsch
What is the most common locations of cholesteatoma to form from most common to least (3)
- posterior epitympanum
- Posterior mesotympanum
- Anterior epitympanum
Where is the most common location for residual cholesteatoma to hide
sinus tympani
How can you check if youve buried epithelium after CWD mastoidectomy?
DWI mri
What is the smallest size cholesteatoma that DWI MRI can detect
3 mm, thats why you want to wait a little before doing it
What is Gallium scan useful for in malignant OE?
To decide when to stop IV abx, every 6 weeks
What type of microbe is most commonly responsible for bullous myringitis
Virus, sometimes mycoplasma
What is the most common malignant tumor of the external ear (pinna)
basal cell carcinoma
Most common malignant tumor of the ear CANAL
squamous cell carcinoma
What is the 5 year survival of T1 and T2 EAC SCC?
90%
What is the 5 year survival of EAC SCC T3/T4
less than 50%
What is the MINIMUM surgery for EAC SCC?
Lateral temporal bone resection
Where may facial nerve pass that puts it at risk during canaloplasty surgery?
Lateral to the annulus at the posterior/inferior level (2% of cases)
What can keratosis obturans be sometimes associated with?
Bronchiectasis/chronic pulmonary disease
What is the CAUSE of keratosis obturans?
Failed epithelial migration
what is the CAUSE of EAC cholesteatoma
Trapped epithelium in bony canal
What glands does the facial nerve give postganglionic parasympathetics to?
Lacrimal, sublingual, submandibular
What is the distance that the facial nerve traverses from the point that it exits the IAC to when it exits the stylomastoid foramen
30 mm
What is the most common cause of hemifacial spasm?
Due to vascular loops from AICA or PICA
Where is the blood supply to the facial nerve located?
epineurium
What degrees of facial injury is going to have absent enog?
Sunderland 3/4/5
What is chromatolysis
Increased neuronal metabolism in the cell body after nerve injury
What is ephaptic transmission
Faulty regeneration of facial nerve causing facial spasm
Wha is the indicdence of bells palsy in children?
1/100,000
Where is facial nerve most likely to be injured during vestibular schwannoma surgery?
The porus
How much length can you get out of the facial nerve if you detach it from the geniculate ganglion?
1 cm
What is the best facial outcome you can get with grafting after a complete paralysis?
HB grade 3
What week of development do the incomplete partition defects arise?
7
What is a good reference point to decide if the Vestibular aqueduct is enlarged?
Should be less than the diameter of the posterior SCC
What are the two T bone abnormalities with Pendred always seen together??
Mondini + Enlarged Vestibular Aqueduct
Of the 3 SCC, which one most often has abnormalities?
LCC, after that superior, superior forms FIRST
What percent of live births/children will test positive for CMV?
1%, only 5-10% will have SNHL
Which Ion channel affected in jervell-lange-nielsen
Potassium
What are the autosomal dominant syndromes
Wardenburg, treacher-collins, Apert, branchio-oto-renal
What syndrome associated with having trapezoid mouth and have stapes fixation?
Apert
what is type 4 tympanoplasty
Shield the round window, exteriorize the footplate
How does middle ear space affect hearing with a TM perf
The smaller the volume of the middle ear, the worse conductive loss you get with a TM perf, location of perforation has little to no effect
In terms of the ossicular chain, the single most important factor that affects hearing is…
Presence if malleus manubrium
Which gender is aural atresia more common in? Boys or girls
Boys, 3:1
In what order does atresia plasty and microtia repair occur
first stage of microtia repair FIRST, then atresia repair
what is most common location for congen cholwsteatoma
anterior meso
most common congen ossicular abnorm
malleus fixation, higher conductive loss at lower freq, caused by anterior nmalleal ligament fixation
How many phases of otosclerosis are tehre
two, otospongiosis phase, sclerotic phase
In which direction is nystagmus in labyrinthitis
First irritative (in direction of the ear), then changes direction to hypofunctional, away from that ear
What do you need to do if someone with CI needs an MRI
They need their magnet removed
What type of insertion of CI better for hearing preservation
Round Window insertion
What are criteria for cochlear implantation for adults
profound snhl (70 dB or higher), less than 50% word recognition on open set (40% for medicaid)
what pathology predisposes to FN stimulation with electrical signal from a cochlear implant
otosclerosis, conduction of the energy through the hardened bone
Whats the most common complication of cochlear implants?
Flap infection
What is the finding on CT that can indicate meningioma?
Hyperostosis
CP angle mass that is the same as CSF, restricted diffusion?
epidermoid
GLomus tumor are more common in X
Females 3:1
How often do you see multiple glomus tumors?
10%
What artery most commonly supplies glomus tumors?
Ascending pharyngeal
What is the pathology pictured
Glomus jugulare
What should you do if you discover a middle ear effusion during cochlear implantation?
Irrigate middle ear with saline, apply ofloxacin drops, and place patient on post op ceftriaxone
What is the inheretence pattern of mondini dysplasia?
autosomal dominant with nons yndromic features (but CAN be seen with BOR and Pendred)
- would double check this
What is more common, NF 1 or NF2?
NF1
