Surgical Perspective

Question 1

What is included in the otologic part of the candidacy evaluation?

Answer 1

• Same considerations as audiologic, in addition to:
• Complete medical history
• Complete otologic history
• Imaging
• Vaccination status
• Is the patient likely to require additional MRI scans in the future?

Question 2

What should be considered as causes of hearing loss?

Answer 2

• Congenital
• Idiopathic
• Infectious
• Ototoxic
• Genetic (SNHL, ANSD)
• Otologic disease
• Vestibular schwannoma
• Radiation
• Far advanced otosclerosis
• Meniere Disease

Question 3

What should be examined with HRCT?

Answer 3

• Bone anatomy, including:
• Mastoid pneumatization
• Position of vascular structures
• Middle ear anatomy
• Position of nVII (evaluation of facial recess)
• Cochlear malformation
• Cochlear ossification
• EVA
• Width of IAC

Question 4

What should be examined with MRI?

Answer 4

• Soft tissue/fluid, including:
• Rule out cochlear ossification based on fluid in the cochlear duct
• Can evaluate presence of auditory and vestibular nerves
• Some protocols can predict spiral ganglion number (Nadol)

Question 5

What two vaccines should a patient receive before undergoing implantation?

Answer 5

• PCV13 (Prevnar)

- PSV/PCV23 (Pneumovax)

Question 6

What are some risks associated with implantation?

Answer 6

• Bleeding, infection, need for further surgery
• Change in taste (temporary or permanent)
• Injury to nVII
• Tinnitus
• Worsening hearing (in all patients)
• CSF leak
• Dizziness
• Numbness of the ear
• Device malfunction/failure

Question 7

What is the surgical procedure for implantation?

Answer 7

1. Conventional otologic position
2. General anesthesia
3. Peri-op abx
   3, nVII monitoring
4. Discuss flap design
5. Flap elevated to expose landmarks of the mastoid cortex (spine of Henle, linea temporalis, mastoid tip)
6. Insertion (either round window or cochleostomy)
7. Immediate post-op x-ray
8. Impedance testing in the OR (rarely done)

Question 8

What are included in post-op instructions?

Answer 8

• Mastoid dressing (keep for 48 hours)
• Keep head elevated on 1-2 pillows for first week
• Keep incision dry until mastoid dressing is removed
• Keep incision moist with Bactroban
• Follow-up 1 week post-op
• Activation 3-4 weeks post-op

Question 9

What is the expected post-op course?

Answer 9

• Pain:
• Swelling
• Ear popping or fullness
• Dizziness
• Drainage
• Change in taste or dry mouth
• Tinnitus
• Watch for signs of a stiff neck, light sensitivity, or severe headaches (CSF leak)

Question 10

Should CI surgery proceed in children with ventilation tubes?

Answer 10

• It is acceptable to place CIs in patients with clean, dry ventilation tubes
• It is also acceptable to place ventilation tubes in otitis prone children with cochlear implants
• Despite theoretic concerns, the reported incidence of complications is low

Question 11

Describe MRI after obtaining CI.

Answer 11

• MRI is limited in patient with ferromagnetic materials because of the risk of implant movement, demagnetization and dysfunction
• Magnet can be surgically removed and then returned but this does not always prevent an artifact in the MRI
• MRI can be performed safely when using a 1.5 T MRI and a tight head wrap

Question 12

What are some rare post-op complications?

Answer 12

• Insertion to the IAC
• nVII stim
• Injury to the nerve to the face
• Intra-op decision to perform a meatal closure

Question 13

What are common cochlear malformations?

Answer 13

• Cochlear aplasia
• Common cavity
• Incomplete partition
• Hypoplasia

Question 14

Describe implantation with cochlear malformations.

Answer 14

• May require fluoroscope guidance
• In ossified cochleae (post meningitis) may require drill-out or split arrays
• Shorter electrodes may be used
• Modiolar hugging vs. lateral wall electrodes
• In the absence of an auditory nerve, may need to use ABIs