Miscellaneous Otology

Question 1

Tumors of the Internal Auditory Canal/Cerebellopontine Angle

Answer 1

1) Acoustic Schwannoma - 90%
2) Meningioma, Arachnoid Cysts, Cholesteatoma, Facial nerve neuroma, Metastatic lesions - 10%

Question 2

Acoustic Schwannoma - Growth Rate

Answer 2

1-4mm/year

Question 3

Effect of Smoking on Tympanoplasty

Answer 3

Smoking is associated with a 3-fold increase in long-term tympanoplasty graft failure.

Question 4

Constant Landmarks in Middle Ear Surgery

Answer 4

1) Jacobsen’s nerve
2) The Cochleariform process
3) Eustachian tube orifice
4) Round Window niche
5) Stapedius tendon/pyramidal process
Note: if the surgeon should become disoriented, stop working in unknown area, then identify a region of known anatomy, and proceed from known to unknown

Question 5

Absolute Contraindications for Tympanoplasty

Answer 5

1) Poor general health
2) Malignant tumor of the outer or middle ear
3) Uncontrolled cholesteatoma
4) Unusual infections - malignant otitis externa
5) Complications of chronic ear disease: meningitis, brain abscess, lateral sinus thrombosis
6) Tympanoplasty is contraindicated in the only or significantly better hearing ear to avoid risk of irreversible SNHL
- Operating on the better hearing ear in pts who can use a hearing aid in the opposite ear may be considered in select cases
7) A non-functioning eustachian tube is a relative contraindication to tympanoplasty (hard to determine preop)
8) Repeated surgical failures - leave the ear alone (secondary to middle ear fibrosis, ET dysfunction, recurrent perforations, prosthesis extrusion)

Question 6

How is stereotactic radiotherapy given for vestibular schwannomas?

Answer 6

1) Given in 1-3 fractionated doses
2) 13 Gray to 21 Gray are given in total
3) Given with a Cyber knife or Gamma knife

Question 7

Follow-Up of patients with vestibular schwannoma following stereotactic radiotherapy.

Answer 7

1) Follow-up of at least 5 years of no growth would capture around 80% of non controlled tumors
2) A follow-up period of 9 years would capture almost all non controlled tumors
3) Very late tumor progression of vestibular schwannomas has been reported following stereotactic radiotherapy (SRS).
- Post SRS tumors that are not growing still retain proliferative capacity

Source:
Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study; Santa Maria, et al, Otology & Neurotology, Vol. 42, No. xx, 2021

Question 8

Vestibular Schwannoma (VS) tumor control rates following stereotactic radio surgery (SRS).

Answer 8

1) Not all VS grow.
2) Some VS go through periods of quiescence before resuming growth
3) VS control rates are worse following SRS in tumors that have documented pre-SRS growth.
- The degree of growth rate prior to SRS may also influence treatment response.
4) Salvage SRS is less likely to control VS tumor growth

Source:
Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study, Santa Maria, et al; Otology & Neurotology, Vol. 42, No xx, 2021

Question 9

Risk Factors for poor tumor control rates in Vestibular Schwannoma following stereotactic radiosurgery.

Answer 9

1) Tumors with documented growth prior to SRS have worse control rates with SRS
2) Patients with NF2 have reduced tumor control with SRS
- There is also a small increase in risk of radiation-induced malignancy in NF2 patients following SRS
3) Larger tumors have reduced control rates with SRS
- Note: Only 17% of intracanalicular VSs are likely to grow with observation
4) Other factors associated with decreased tumor control
- Female gender: women are 50% more likely to experience non control

Source:
Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study; Santa Maria; Otology & Neurotology, Vol. 42, No. xx, 2021

Question 10

Salvage therapy for vestibular schwannoma following stereotactic radiosurgery.

Answer 10

When VSs are not controlled by SRS, these authors recommend salvage surgery in most patients.
- This uses a different modality to control tumor and provides a histological diagnosis
- When SRS fails to control VS tumor growth, repeat radio therapy does not reliably control tumor growth

Source:
Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study; Santa Maria, et al, Otology & Neurotology, Vol. 42, No. xx, 2021

Question 11

Surgery After Stereotactic Radio Surgery For Vestibular Schwannomas - What Are The Issues?

Answer 11

1) Cranial nerve injuries are more likely
2) There is a reduced completeness of resection
3) There are higher rates of postoperative complications
4) VS tumors that fail SRS are likely to be more biologically aggressive
- Subtotal resection of these tumors improves facial nerve outcomes, but the patients are at higher risk for continued growth after subtotal resection

Source:
Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas - A Retrospective Cohort Study, Santa Maria et al., Otology & Neurotology, 2021

Question 12

Malignant Vestibular Schwannomas - What is the Risk?

Answer 12

1) 1/1041 Vestibular Schwannomas are malignant
2) About half of malignant Vestibular Schwannomas present as benign vestibular schwannomas
3) Malignant transformation of VS following a single treatment of SRS is about 0.3%
- Malignant transformation rate is higher with single dose SRS as opposed to fractionated treatment
- Patients with NF2 are at higher risk for malignant degeneration of a VS
4) Pathology of malignant VS
- Malignant peripheral nerve sheath tumor, triton tumor, or sarcoma
5) Malignancy in VSs following SRS is rare - most reported cases are associated with single-fraction SRS as opposed to fractionated therapy

Question 13

What are the control rates for Vestibular Schwannoma following Stereotactic Radiotherapy?

Answer 13

1) Sporadic VS = 89% at 3 years
2) NF2 VS = 43% at 3 years

Question 14

What is the main concern on a vestibular schwannoma that changes from typical to atypical behavior following stereotactic radiotherapy?

Answer 14

Any VS that changes behavior following SRS should be considered for malignant change.

Question 15

Lesions of the Petrous Apex

Answer 15

1) Primary lesions of the petrous apex:
- Cholesterol granuloma
- Cholesteatoma/Epidermoid cyst
- Mucocele
- Trapped fluid/effusion
- Eosinophilic granuloma
- Mesenchymal tumor (chondroma, chondrosarcoma, osteoclastoma, fibrous dysplasia)
- Petrous apex encehalocele

2) Secondary lesions of the Petrous Apex:
- Direct spread of neoplasm (nasopharyngeal carcinoma, vestibular or jugular foramen schwannoma, trigeminal neuroma, glomus tumor, clival chordoma, meningioma)
- Metastasis or hematogenous spread (metastatic tumor, lymphoma)
- Infection (osteomyelitis, necrotizing external otitis)
- Other (arachnoid cyst, aneurysm or internal carotid artery, sphenoid mucocele)

Question 16

Cystic lesions of the Petrous Apex - Differential diagnosis

Answer 16

99% of primary cystic lesions of the Petrous Apex are one of the following:
1) Cholesterol granuloma
2) Cholesteatoma/epidermoid cyst
3) Mucocele

Question 17

What is a cholesterol granuloma of the petrous apex?

Answer 17

A cholesterol granuloma of the petrous apex is a foreign body giant cell reaction to cholesterol deposits, with chronic inflammation, fibrosis, and vascular proliferation that is contained within a fibrous capsule.
- Cholesterol granulomas are 10 times more common than a cholesteatoma
- Cholesterol granulomas are 40 times more common than mucoceles

Question 18

What causes a petrous apex cholesterol granuloma?

Answer 18

1) The obstruction/vacuum theory: obstruction of a previously aerated space leads to gas trapping and resorption, vacuum formation, hemorrhage into the mucosal surface, inflammation, breakdown of red blood cells, and formation of cholesterol crystals. With the formation of cholesterol crystals, the inflammation cascade is initiated with bony resorption and foreign body reaction.

2) The exposed marrow theory: during development aggressive pneumitization of the apex forms pathologic communications between the mucosa lined air cells and the marrow they gradually replace, creating hemorrhage into the apical air cells. Red blood cells break down, cholesterol crystals form, and the inflammatory cascade begins.

Question 19

What is Gradenigo’s Triad?

Answer 19

1) Otorrhea
2) Deep retroocular pain
3) Abducens nerve palsy

Note: Gradenigo’s triad is associated with petrous apicitis

Question 20

What viruses are known to cause audio vestibular symptoms?

Answer 20

1) Herpes Viruses: CMV, HSV, VZV, EBV
2) Paramyxoviradae: Parainfluenza, mumps, measles
3) Polio virus
4) Rubella virus
5) Influenza virus
6) HIV
7) Hepatitis viruses
8) Flaviviruses: Zika virus, Dengue virus

Question 21

What Audiovestibular Symptoms Occur in Patients with COVID-19 Infections?

Answer 21

1) 90% common COVID-19 symptoms: Fever, cough, dyspnea and/or fatigue 21 days before and 14 days after onset of hearing loss, tinnitus, or vertigo
2) 70% of patients developed audiovestibular symptoms after other COVID-19 symptoms
3) Audiovestibular symptoms can be the presenting symptoms of a COVID-19 infection

Question 22

What audiovestibular symptoms do patients have after a COVID-19 infection?

Answer 22

1) Tinnitus - 23%
2) Dizziness/Vertigo - 18%
3) Dizziness/Vertigo improves with time after COVID infection

Question 23

What are the symptoms of ‘Long COVID?’

Answer 23

1) General: Fatigue, muscular weakness, joint pain
2) Lungs: Dyspnea, cough, persistent 0xygen requirement
3) Brain: Anxiety, Depression, PTSD, Brain Fog, Headaches
4) Heart: Palpitations, Chest Pain
5) Blood Vessels: Thromboembolism
6) Kidneys: Chronic kidney disease
7) Skin: Hair loss

Question 24

COVID-19 Vaccines and Sudden Hearing Loss

Answer 24

1) Most studies have found that COVID-19 vaccination does not significantly increase the risk of SSNHL.
- One study reported an increased risk of SSNHL (Yanir et al, 2022, JAMA OHNS), but the effect was small
2) The benefits of COVID-19 vaccine outweigh its risk for causing SSNHL

Question 25

Vaccine Adverse Event Reporting System (VAERS) - What is this and when is it used?

Answer 25

1) Healthcare providers are required by law to report:
- Serious adverse events (AEs) regardless of causality (e.g., death, birth defect, hospitalization)
- Cases of multisystem inflammatory syndrome
- Cases of myocarditis or pericarditis

2) Healthcare providers are encouraged to report:
- Any AEs
- Vaccine administration errors, whether or not associated with an AE

Question 26

What causes presbycusis?

Answer 26

Age related hearing loss correlates with hair cell loss more than strial degeneration.

Source:
Age-Related Hearing Loss Is Dominated by Damage to Inner Ear Sensory Cells, Not the Cellular Battery That Posers Them
Wu, et al

Question 27

What are the complications of Otitis Media and Mastoiditis?

Answer 27

1) Intratemporal Complications:
- Hearing Loss: CHL or SNHL
- Vestibular dysfunction
- Tympanic membrane perforation
- Mastoiditis
- Acquired cholesteatoma
- Facial nerve dysfunction
- Labyrinthine Fistula: in 10% of pts with COM with cholesteatoma
- Petrous Apicitis

2) Extratemporal Complications:
- Typically, extension of acute mastoiditis: Subperiosteal abscess, Citelli abscess, Bezold abscess, Luc abscess, Zygomatic root abscess

3) Intracranial Complications:
- Meningitis
- Lateral sinus thrombosis
- Subdural empyema
- Intraparenchymal brain abscess
- Otitis hydrocephalus

Question 28

What are the goals of surgery in chronic otitis media?

Answer 28

1) To create a safe, clean, and dry ear
2) To preserve hearing

Question 29

How can you improve eustachian tube function?

Answer 29

1) Treat Sino nasal disease: Eustachian tuboplasty, allergy treatment
2) Treat laryngopharyngeal reflux
3) Stop tobacco/marijuana use
4) Clear obstruction of the nasopharynx and protympanum
5) PE tube placement
6) Can you separate the mastoid/middle ear and indirectly improve eustachian tube function?
- via either CWD/mastoid obliteration?

Question 30

What types of surgery can be done on the middle ear/mastoid in chronic otitis media surgery?

Answer 30

1) Tympanoplasty
2) Endaural atticotomy
3) CWU tympanomastoidectomy
4) CWD tympanomastoidectomy
5) Canal wall reconstruction/mastoid obliteration (CWR/MO)
6) Subtotal petrosectomy/blind sac closure

Note: Advances - endoscopic, laser?

Question 31

Canal Wall down mastoidectomy - what are the advantages and disadvantages?

Answer 31

1) Advantages:
- CWD Mastoidectomy is the gold standard for treatment of COM/Cholesteatoma
- Recidivism rate of 2-5%
- May need just one operation
2) Disadvantages:
- Cosmetic: meatoplasty
- Need for mastoid bowl cleaning
- Not physiologic: persistent otorrhea
- Propensity to caloric stimulus
- Pediatric patients/Mental Retardation Developmental Delay
- Hearing aid difficulties
- Water precautions

Question 32

What types of otalgia are there?

Answer 32

1) Primary otalgia - pain that arises from pathology of the external, middle, and inner ear
2) Secondary/Referred Otalgia - pain that arises from pathology outside the ear

Question 33

What is the differential diagnosis of primary otalgia?

Answer 33

1) Infection - most common cause of primary otalgia
- Otitis externa
- Otitis media
- Bullous myringitis
- Cellulitis of the pinna
- Perichondritis
- Herpes zoster oticus
2) Cerumen impaction
3) Foreign bodies
4) Eustachian tube dysfunction
5) Trauma - lacerations, hematoma of the pinna
6) Relapsing polychondritis
7) Cholesteatoma
8) Neoplasm of the ear - BCCA, SCCA, Melanoma

Question 34

What is the differential diagnosis of secondary/referred otalgia?

Answer 34

1) Dental infection/inflammation
2) TMJ disorders
3) Trigeminal neuralgia
4) Sinonasal patthology
5) Laryngeal/pharyngeal pathology:
- Laryngtitis
- Pharyngitis
- Tonsillitis
- Post tonsillectomy pain
- Peritonsillar abscess
6) Head & Neck cancers
7) Musculoskeletal pathology
- Cervical spine disease
- Myofascial pain syndrome
8) Eagle’s syncrome
9) Temporal arteritis
10) Thyroiditis
11) GERD
12) Cardiac - angina, acute coronary syndrome

Question 35

What is the Tullio Phenomenon?

Answer 35

1) The Tullio phenomenon is a symptom/physical exam finding in which nystagmus or vertigo are induced in response to sound.

Question 36

What are the causes of Tullio’s Phenomenon?

Answer 36

1) Superior Semicircular Canal Dehiscence
2) Otosclerosis
3) Congenital syphilis with osteomyelitis of the boney labyrinth.
- Miliary Gummas form on the endosteum leading to labyrinthine fistulae
4) Meniere’s disease
5) Perilymph fistula
6) Cholesteatoma with semicircular canal erosion and fenestration
7) Head trauma
8) Normal patients
9) Post stapedectomy
10) Collapsed canal syndrome
11) Congenital deafness
12) Seronegative Lyme Borreliosis
13) Middle ear osteoma`

Question 37

What is the incidence of Acoustic Schwannoma in a patient with asymmetrical hearing loss?

Answer 37

The incidence of acoustic schwannoma in a patient with asymmetrical hearing loss is 0.85% to 15.8%.

Reference: Predictors of Abnormal MRI Findings in Patients With Asymmetrical Sensorineural Hearing Loss. Prayuenyong P, Pitathawatchai P, et al: Laryngoscope; 2024; (October 12)

Question 38

What is the best predictor of an acoustic schwannoma on MRI?

Answer 38

Hearing asymmetry of at least 15dB at 1000Hz is the best predictor of acoustic schwannoma on MRI:
1) Sensitivity = 84%
2) Specificity = 48%
3) Odds ratio = 4.87

Reference: Predictors of Abnormal MRI Findings in Patients With Asymmetrical Sensorineural Hearing Loss. Prayuenyong P, Pitathawatchai P, et al: Laryngoscope; 2024; (October 12)