Cochlear implants are electronic prosthetics that bypass damaged hair cells and directly stimulate the auditory nerve. They consist of an internal component that is surgically implanted and an external component. The surgical technique involves making a post-auricular incision, performing a mastoidectomy to access the cochlea, drilling a recess for the internal receiver, inserting the electrode array into the cochlea, and closing layers. Proper patient selection involves assessing hearing loss severity and lack of benefit from hearing aids. Potential complications include facial nerve injury and infection. Outcomes are generally good for improving hearing and quality of life.

1. SurgicalTechnique of
Cochlear Implant
Dr.Tabeer Arif

2. Layout
• Introduction
• Mechanism of action
• Indications
• Contraindications
• Work up
• Surgical techniques
• Complications
• Outcome

3. Introduction
• Cochlear implants are implantable electronic prostheses designed to
convert mechanical sound energy into electrical signals that directly
stimulate the auditory nerve with the help of multiple electrode array
situated in close proximity to the cochlear nerve in severely to profoundly
deaf individuals

4. • Not a hearing aid
• A true bionic sense organ

5. History of Cochlear Implant
• 18th century-Volta
• 1957 – Djourno & Eyeries – direct auditory nerve stimulation - a clear auditory
percept.
• 1961 – House & Doyle – put electrodes in scala tympani of 2 profoundly deaf
adults & got a clear auditory response
• 1972 – First single channel cochlear implant developed.
• 1985 – FDA approved CI for adults
• 1990 - FDA approved age for CI 2 years and up

6. Mechanism of Action
• Bypasses all hearing mechanism till hair cells and directly stimulate the
auditory nerve
• Internal component:
Electrode array and receiver-stimulator
• External component:
Speech processor, head piece and battery

12. Types Of Implants
• MED-EL
• Advanced Bionics
• Cochlear
• Neurelec

13. Indications (Adults)
• Age – More than 18 years
• Bilateral severe to profound Sensorineural hearing loss.
• Post-lingual Deafness
• Little or no benefit from hearing aids.
• Sentence recognition test <50%
• No anatomical contraindication
• Lack of medical contraindication including psychological instability

14. Children
• 12 months or older
• Bilateral severe-to-profound sensorineural hearing loss with PTA of 90 dB or
greater in better ear
• No appreciable benefit with hearing aids (parent survey when <5 y or 30% or
less on sentence recognition when >5 y)
• Tolerance for wearing hearing aids
• Enrolled in aural/oral education program
• No medical or anatomic contraindications
• Motivated parents

15. Contraindications
• Vestibulocochlear nerve lesion, CNVIII atresia
• Agenesis of cochlea (michel deformity)
• Neurofibromatosis II
• Active middle ear disease
• Psychosis, mental retardation, severe organic brain dysfunction
• Unrealistic expectations

16. Selection of Ear
• Better hearing ear
• Most recently deaf ear
• Most radiographically favorable anatomy (well-pneumatized mastoid,
normal facial nerve anatomy, normal inner ear development, and patent
cochlea)
• Least obstructed labyrinth

17. Work Up
• History (including complete medical and psychological evaluation)
• ENT examination
• Audiological testing (PTA, Speech audiometry , Aided audiometry , BERA,
OAE)
• HRCT
• MRI (cochlear dysplasia, LVA, cochlear nerve)
• Trial of high power hearing aids
• Meningitis prophylaxis

18. SurgicalTechniques
• Approaches:
Trans-mastoid approach
Middle cranial fossa approach

19. • Pre-op antibiotic
• Under GA
• Without muscle relaxant
• Facial nerve monitor
• Templates of speech processor and internal reciever

21. • Infiltration with local anesthesia
• Post-auricular Incision with posterosuperior extension (from temporalis
muscle superiorly to mastoid periosteum inferiorly)

23. • Skin flaps are then developed anteriorly to the ear canal and posteriorly to
allow for placement of the internal receiver.
• An anteroinferiorly based musculoperiosteal flap is then created by incising
the temporalis fascia, muscle, and periosteum
• Spine of Henle

25. • Mastoidectomy is done without saucerization
• Once mastoid antrum is entered LSSC identified and drilling continuous
anterosuperiorly until the body of the incus is identified
• Posterior tympanotomy through facial recess (1-3mm diamond burr –
copious irrigation)

28. • Bony recess for internal receiver is drilled (templates and dummy receiver)
• Cochleostomy done (1mm diamond burr)
• Device is placed in this recess and secured in place
• Electrode is inserted into the scala tympani through cochleostomy and
sealed with temporalis muscle

33. • Intraoperative measurements (neural-response telemetry and impedence
testing) are obtained to confirm proper functioning of the device before or
during wound closure.
• Wound is closed in layers

35. Complications
• Facial nerve injury
• Alteration of taste
• Infection
• Dizziness
• Wound dehiscence
• Device failure
• CSF leak

37. • Meningitis
• Otitis media
• Device extrusion
• Displacement of electrodes

38. Post- op care
• Can be discharge on the day of operation
• 7 days oral antibiotic
• Mastoid dressing opened after 24 hours
• Follow up visit 1 week
• External device fitted 4 weeks after the surgery
• programming and rehabilitation begin

39. Recent Advances
• Bilateral implants
• Minimally invasive implant techniques

40. Conclusion
• The overall prognosis for hearing improvement and improved quality of life
in the properly selected patient is excellent.

41. Thank you.