Cochlear Implants

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Cochlear Implants

• Dr A. Awad
• Department of Otolaryngology, Head Neck Surgery
• Teshreen Hospital

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What is a cochlear implant

• Surgically implanted electronic device that can
  help provide a sense of sound to a person who is
  profoundly deaf, or severly hard of hearing
• The cochlear implant is often referred to as
  bionic ear
• Unlike other kinds of hearing aids the cochlear
  implants dose not amplify sound, but works by
  directly stimulating any functioning auditory
  nerves inside the cochlea with electrical
  impulses

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History of Cochlear Implants

• Alessandro Volta 1880
• Djourno and Eyries 1957
• House, Doyle, Simmons 1961
• 1972 Single-channel implant
• 1984 FDA approval,Nucleus22
• 2006, 120 000 implantations

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Devices

• Advanced Bionics (US)
• Cochlear (Australia)
• Med-el (Austria)
• Neurelec (France)
• All hear (US) which is a single channal device.
  Its not FDA approved.

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Components
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Components of Cochlear Implant
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Anatomy
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Indication for Cochlear Implant

• Adults
• 18 years old and older (no limitation by age)
• Bilateral severe-to-profound sensorineural
  hearing loss (70 dB hearing loss or greater with
  little or no benefit from hearing aids after 6
  months trial)
• Psychologically suitable
• No anatomic contraindications
• Medically not contraindicated

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Indications for Cochlear Implantation --
Childrencurrent criteria

• 12 months or older
• Bilateral severe-to-profound sensorineural
  hearing loss
• No appreciable benefit with hearing aids after
  3-6 months trial
• Enrolled in aural/oral education program
• No medical or anatomic contraindications
• Motivated parents

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General Workup

• Audiologic evaluation
• Medical evaluation
• Speech-language evaluation
• Psychological/rehabilitation evaluation

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CT Findings
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CT Findings
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Contraindications

• Neurofibromatosis II, mental retardation,
  psychosis, organic brain dysfunction, unrealistic
  expectations
• Active middle ear disease
• Perforation of TM
• CT findings of cochlear agenesis (Michel
  deformity) or small IAC (CN8 atresia)
• Dysplasia not necessarily a contraindication, but
  informed consent is a must
• CWD mastoidectomy
• Cochlear ossification
• Advanced otosclerosis

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Risks of CI Surgery(ASHA technical Reports 2004)

• Injury to the facial nerve
• Post operative dizziness
• Meningitis
• Leakage of CSF
• Delayed device failure (less than 2)
• Device migration or extrusion (rare)

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Special Instrumentation

• Metal Template
• Silicon Implant Template
• Bone recess template
• Array exit marking template
• Recess checking gauge
• Electrode claw
• Micro forceps with parallel tips
• Spacer for intraoperative testing
• Surgical burrs (0.6 mm-1.2 mm-3 mm)
• Facial nerve monitoring

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Surgical Technique Incisions
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Drill Implant Bed, Electrode Channel, Suture
Holes, And Mastoidectomy
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Posterior tympanotomy
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Posterior tympanotomy
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Cochleostomy
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Inserting The Electrode Array
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Fixation Of The Implant
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Post-op X-ray View
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• Activation of the Device 4 to 6 weeks after
  surgery
• The programming of the external speech processor
  is a procedure that must be repeated one week
  later and then periodically thereafter

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Results of Implantation

• Wide range of outcomes
• Improvement is long-term (Waltzman, et al. 5-15
  yr f/u)
• Implantation is cost effectiveeven in the
  elderly (Francis, et al)
• Research indicates recipe for success includes
• Short length of time from deafness to
  implantation (Sharma showed lt3.5 years regain
  normal latencies within 6 mos. After 7 years,
  little plasticity remains)
• Experience with language before onset of deafness
• Implantation before age six for prelingually
  deafened children
• Aural/oral education
• Highly motivated patients/parents

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Results of Implantation

• Beadle, et al (2005)
• 30 profoundly deaf children
• at 10 years follow up
• 26 understood conversation without lip reading
• 18 used telephone with a familiar speaker
• At 10-14 years
• 19 were at secondary schools
• 6 in mainstream schools
• 7in specially schools
• 6 in schools for the deaf
• Govaerts, et al showed 90 of children implanted
  lt2yo were integrated into mainstream vs. only
  20-30 if implanted after age 4

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References

• 1ASHA, http//www.asha.org/public/hearing/
  treatment/cochlear_implant.htm
• 2waltzman, s. and Shapiro, w. (2007 Cochlear
  implants in adults. In Valente, Hosford-Dunn and
  Roesser(eds) Audiology treatment. New York
  Thieme Medical Publisher, Inc.
• 3ASHA Technical Reports 2004
• 4ASHA Technical Reports 2004
• 5Sharma et al
• 6Int J Pediatric otorhinolaryngology, PubMed ID
  10577804
• 7Acta otolaryngology PubMed ID 12701751
• 8Adapted from American Speech-Language-Hearing
  association, 1997.

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THANK YOU