oto Tbone malignancies/Trauma

Question 1

What is the most common cutaneous malignancy

involving the auricle?

Answer 1

Basal cell carcinoma is both the most common auricular

malignancy as well as the most common skin cancer in general.

Question 2

What is the most common ceruminous gland

malignancy of the external auditory canal?

Answer 2

Adenoid cystic carcinoma

Question 3

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?

Answer 3

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.

Question 4

List common risk factors associated with the

development of temporal bone malignancy.

Answer 4

Fair complexion, sun exposure, immunocompromised

status, recurrent otitis externa, previous radiation

Question 5

List the most common types of temporal bone

malignancy.

Answer 5

Approximately 70% squamous cell carcinoma, ~ 11% basal
cell carcinoma, 4% adenocarcinoma, 4% adenoid cystic
carcinoma

Question 6

Describe the clinical presentation of squamous cell

carcinoma of the external auditory canal?

Answer 6

Approximately 80% otorrhea and otalgia, ~ 70% hearing

loss, 30% facial nerve disturbances

Question 7

Describe the T staging of EAC carcinoma?

Answer 7

● 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)

Question 8

When is radiation indicated for patients with EAC

squamous cell carcinoma?

Answer 8

T3–T4 disease, close margins, multiple positive lymph

nodes, extracapsular spread, and perineural invasion

Question 9

When is lateral temporal bone resection indicated
in management of squamous cell carcinoma of the
EAC?

Answer 9

Disease that is limited to the external auditory canal without
significant extension into the mastoid, middle ear, or
beyond (T1 and T2 disease).

Question 10

What is the most common malignancy of the

petrous apex?

Answer 10

Metastasis (breast). The low-flow marrow of the petrous apex

is particularly susceptible to hematogenous metastasis.

Question 11

What is the most common malignant tumor of the

temporal bone in children?

Answer 11

Rhabdomyosarcoma, embryonal subtype

Question 12

What is the appropriate initial management

strategy for a carcinoid tumor of the middle ear?

Answer 12

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.

Question 13

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?

Answer 13

The distal branches of the nerve can still be stimulated for
approximately 3 days after they are transected, before
wallerian degeneration takes place.

Question 14

Describe the two most common classifications for

temporal bone fractures.

Answer 14

Orientation of the fracture line (longitudinal, transverse, or
mixed) or by involvement of the otic capsule

Question 15

Describe associated sequelae of a longitudinal

temporal bone fracture.

Answer 15

CSF otorrhea, tympanic membrane perforation, EAC laceration, conductive hearing loss from hemotympanum or ossicular discontinuity, bloody otorrhea, facial nerve injury
uncommon (20%)

Question 16

Describe associated sequelae of a transverse

temporal bone fracture.

Answer 16

Vertigo, SNHL, facial nerve injury more common and often
more severe (30 to 50%)

Question 17

What type of head blow is likely to cause a

longitudinal temporal bone fracture?

Answer 17

Temporal (lateral) blows are more likely to cause a
longitudinal fracture, whereas frontal or occipital blows may
cause a transverse fracture.

Question 18

Describe the initial management of a traumatic

CSF leak.

Answer 18

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.

Question 19

Review the role of antibiotics with traumatic

temporal bone CSF leaks.

Answer 19

Controversial. A recent Cochrane Database review does not
support the use of prophylactic antibiotics to reduce the
risk of meningitis after basilar skull fractures.

Question 20

Review the role of perioperative antibiotics in

otologic and neurotologic surgery.

Answer 20

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.

Question 21

What is the initial management of a temporal
bone fracture with an intact otic capsule, intact
tympanic membrane, and hemotympanum with conductive hearing loss?

Answer 21

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.

Question 22

Where is the most common site of ossicular chain
disruption in the setting of temporal bone
fracture?

Answer 22

The incudostapedial joint

Question 23

What is the most common site of facial nerve

injury in temporal bone fractures?

Answer 23

The perigeniculate region (80% +)

Question 24

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?

Answer 24

Conservative management and observation. The vast

majority of these perforations will heal spontaneously.

Question 25

What is the most common otologic sequelae of | lightning strike?

Answer 25

Tympanic membrane perforation

Question 26

What needs to be done before burying a traumatically avulsed portion of the pinna in a postauricular subcutaneous pocket?

Answer 26

The skin of the avulsed segment should be dermabraded to remove the surface epithelium while it is buried in the subcutaneous pocket.

Question 27

What is the mechanism for SNHL resulting from | decompression sickness?

Answer 27

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.

Question 28

What are the symptoms of perilymphatic fistula?

Answer 28

Fluctuating hearing loss and intense vertigo that worsens with Valsalva or exertion

Question 29

Describe the clinical presentation and radiologic | findings of labyrinthine concussion.

Answer 29

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.

Question 30

Describe the most common mechanism of malleus handle fracture.

Answer 30

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.

Question 31

How should bloody otorrhea after temporal bone | fracture in a stable and awake patient be managed?

Answer 31

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.

Question 32

Describe the utility of the "halo" or "ring" sign when | evaluating for traumatic CSF leak.

Answer 32

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.

Question 33

In what body fluids can β-2 transferrin can be | found?

Answer 33

CSF, perilymph of the inner ear, and vitreous humor of the | globe

Question 34

What initial screening tests should be performed | when a CSF leak is suspected?

Answer 34

β2-transferrin and a fine cut CT of the entire skull base should be obtained with dedicated coronal and axial acquisition.

Question 35

How long is CSF (beta-2 transferrin) stable for at | room temperature?

Answer 35

Approximately 4 hours at room temperature, and approximately 3 days when refrigerated (not frozen).

Question 36

Describe the Dandy maneuver.

Answer 36

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.

Question 37

How much CSF is contained within the subarachnoid space at any given time?

Answer 37

Approximately 150 mL, with daily production of approximately 500 mL, which means that the CSF volume is turned over approximately three times per day.

Question 38

Describe a positive reservoir sign.

Answer 38

Intermittent CSF rhinorrhea associated with change in head position, which results from pouring of CSF collecting in a dependent location of a sinus.

Question 39

Describe Hyrtl fissure.

Answer 39

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).

Question 40

Review possible sources for congenital CSF leaks | involving the temporal bone.

Answer 40

● Hyrtl fissure ● Dilated cochlear aqueduct ● Dilated fallopian canal ● Enlarged petromastoid canal (subarcuate canal) ● Abnormal communication between IAC and inner ear (cochlear malformations)

Question 41

What is the preferred management strategy for traumatic carotid-cavernous fistula associated with skull base fracture?

Answer 41

Endovascular repair (Ballooning/stenting/coiling)