oto Tbone malignancies/Trauma Flashcards
What is the most common cutaneous malignancy
involving the auricle?
Basal cell carcinoma is both the most common auricular
malignancy as well as the most common skin cancer in general.
What is the most common ceruminous gland
malignancy of the external auditory canal?
Adenoid cystic carcinoma
You suspect a malignancy in a patient with an
irregular, pigmented, and ulcerated lesion of the left lobule. Which biopsy techniques are acceptable in ascertaining a diagnosis?
A full-thickness biopsy is necessary for diagnosis. This
should include epidermis, dermis, and some underlying subcutaneous tissue. Shave biopsies or fine needle aspira-
tion of pigmented cutaneous malignancies are inappropri-
ate because they may make tumor staging impossible.
List common risk factors associated with the
development of temporal bone malignancy.
Fair complexion, sun exposure, immunocompromised
status, recurrent otitis externa, previous radiation
List the most common types of temporal bone
malignancy.
Approximately 70% squamous cell carcinoma, ~ 11% basal
cell carcinoma, 4% adenocarcinoma, 4% adenoid cystic
carcinoma
Describe the clinical presentation of squamous cell
carcinoma of the external auditory canal?
Approximately 80% otorrhea and otalgia, ~ 70% hearing
loss, 30% facial nerve disturbances
Describe the T staging of EAC carcinoma?
● T1: Limited to EAC without bony erosion
● T2: Limited to the EAC with limited (not full thickness)
bony erosion
● T3: Tumor eroding through the EAC, involvement of the
middle ear or mastoid, or facial nerve weakness
● T4: Tumor invading otic capsule, jugular foramen, carotid
canal, or dura
(Pittsburgh staging system)
When is radiation indicated for patients with EAC
squamous cell carcinoma?
T3–T4 disease, close margins, multiple positive lymph
nodes, extracapsular spread, and perineural invasion
When is lateral temporal bone resection indicated
in management of squamous cell carcinoma of the
EAC?
Disease that is limited to the external auditory canal without
significant extension into the mastoid, middle ear, or
beyond (T1 and T2 disease).
What is the most common malignancy of the
petrous apex?
Metastasis (breast). The low-flow marrow of the petrous apex
is particularly susceptible to hematogenous metastasis.
What is the most common malignant tumor of the
temporal bone in children?
Rhabdomyosarcoma, embryonal subtype
What is the appropriate initial management
strategy for a carcinoid tumor of the middle ear?
A recent review (Ramsey et al, 2005) identified this rare
tumor as a low-grade malignancy with the potential for
local recurrence and regional metastasis. Complete excision
of this tumor with long-term surveillance is recommended.
In cases of penetrating facial trauma where
branches of the facial nerve are suspected to be
transected, why should they be explored within 3
days?
The distal branches of the nerve can still be stimulated for
approximately 3 days after they are transected, before
wallerian degeneration takes place.
Describe the two most common classifications for
temporal bone fractures.
Orientation of the fracture line (longitudinal, transverse, or
mixed) or by involvement of the otic capsule
Describe associated sequelae of a longitudinal
temporal bone fracture.
CSF otorrhea, tympanic membrane perforation, EAC laceration, conductive hearing loss from hemotympanum or ossicular discontinuity, bloody otorrhea, facial nerve injury
uncommon (20%)
Describe associated sequelae of a transverse
temporal bone fracture.
Vertigo, SNHL, facial nerve injury more common and often more severe (30 to 50%)
What type of head blow is likely to cause a
longitudinal temporal bone fracture?
Temporal (lateral) blows are more likely to cause a
longitudinal fracture, whereas frontal or occipital blows may
cause a transverse fracture.
Describe the initial management of a traumatic
CSF leak.
Most traumatic leaks resolve with conservative measures,
including bed rest, head of bed elevation, and stool
softeners. Generally, surgical repair is pursued if an active
leak persists beyond a week from injury.
Review the role of antibiotics with traumatic
temporal bone CSF leaks.
Controversial. A recent Cochrane Database review does not
support the use of prophylactic antibiotics to reduce the
risk of meningitis after basilar skull fractures.
Review the role of perioperative antibiotics in
otologic and neurotologic surgery.
Available data do not support the use of perioperative
antibiotics in routine otologic surgery. In cases with active
infection, the role of antibiotics is more controversial. A
single dose of perioperative antibiotics is generally recom-
mended in cochlear implantation and skull base proce-
dures, with many surgeons extending this to a 24-hour-long
postoperative course.
What is the initial management of a temporal
bone fracture with an intact otic capsule, intact
tympanic membrane, and hemotympanum with conductive hearing loss?
Audiogram in 4 to 8 weeks. Otic drops can be considered if
there is a laceration or blood in the ear canal. Persistent
conductive hearing loss may suggest the presence of
ossicular chain disruption.
Where is the most common site of ossicular chain
disruption in the setting of temporal bone
fracture?
The incudostapedial joint
What is the most common site of facial nerve
injury in temporal bone fractures?
The perigeniculate region (80% +)
Describe the initial management of a tympanic
membrane perforation related to a nonexplosive
blast injury, such as a slap to the side of the head?
Conservative management and observation. The vast
majority of these perforations will heal spontaneously.
What is the most common otologic sequelae of
lightning strike?
Tympanic membrane perforation
What needs to be done before burying a
traumatically avulsed portion of the pinna in a
postauricular subcutaneous pocket?
The skin of the avulsed segment should be dermabraded to
remove the surface epithelium while it is buried in the
subcutaneous pocket.
What is the mechanism for SNHL resulting from
decompression sickness?
Nitrogen, which was made temporarily soluble in blood by
increased ambient pressure, comes out of solution in the
form of bubbles during rapid depressurization. These
“microbubble emboli” can involve the microcirculation of
the ear and cause hearing loss, and they may be difficult to
distinguish from inner ear barotrauma.
What are the symptoms of perilymphatic fistula?
Fluctuating hearing loss and intense vertigo that worsens with Valsalva or exertion
Describe the clinical presentation and radiologic
findings of labyrinthine concussion.
Brief loss of consciousness associated with transient (days
to weeks) vestibular symptoms, possible hearing loss and
tinnitus. Dix-Hallpike maneuver does not elicit symptoms.
CT scan does not show acute intracranial complications or
otic capsule fracture.
Describe the most common mechanism of malleus handle fracture.
It is often caused by placing wet finger in ear canal. When
the finger is withdrawn under a seal, this creates negative
pressure in the ear canal that can result in fracture of the
malleus. Patients often report a “pop” with sharp pain and
immediate hearing decline.
How should bloody otorrhea after temporal bone
fracture in a stable and awake patient be managed?
Otomicroscopy to debride the EAC. Irrigation or occlusion
(except in cases of massive bleeding) of the EAC should not be performed because of the risk of ascending meningitis.
Describe the utility of the “halo” or “ring” sign when
evaluating for traumatic CSF leak.
Not sensitive or specific. The halo sign may be seen when
blood is mixed with CSF, saline, nasal mucus, and tap water.
Futhermore, the concentration of CSF and blood must be
correct for a halo to be seen.
In what body fluids can β-2 transferrin can be
found?
CSF, perilymph of the inner ear, and vitreous humor of the
globe
What initial screening tests should be performed
when a CSF leak is suspected?
β2-transferrin and a fine cut CT of the entire skull base
should be obtained with dedicated coronal and axial
acquisition.
How long is CSF (beta-2 transferrin) stable for at
room temperature?
Approximately 4 hours at room temperature, and approximately 3 days when refrigerated (not frozen).
Describe the Dandy maneuver.
The patient leans forward while performing a Valsalva. This
maneuver may provoke clear rhinorrhea in a patient with a
CSF fistula. The nostril that the drainage comes from
generally predicts the laterality of the defect.
How much CSF is contained within the subarachnoid space at any given time?
Approximately 150 mL, with daily production of approximately 500 mL, which means that the CSF volume is turned over approximately three times per day.
Describe a positive reservoir sign.
Intermittent CSF rhinorrhea associated with change in head
position, which results from pouring of CSF collecting in a
dependent location of a sinus.
Describe Hyrtl fissure.
A Hyrtl fissure is an embryonic anomaly that leaves a
connection between the middle ear and posterior fossa
(between the jugular bulb and otic capsule). It may be a
conduit for CSF leak, meningitis, or tumor spread (also
known as the tympanomeningeal fissure).
Review possible sources for congenital CSF leaks
involving the temporal bone.
● Hyrtl fissure
● Dilated cochlear aqueduct
● Dilated fallopian canal
● Enlarged petromastoid canal (subarcuate canal)
● Abnormal communication between IAC and inner ear
(cochlear malformations)
What is the preferred management strategy for
traumatic carotid-cavernous fistula associated with
skull base fracture?
Endovascular repair (Ballooning/stenting/coiling)
