This document provides an overview of cochlear implants, including: - A cochlear implant is an electronic device that converts sound into electrical signals to stimulate the auditory nerve for people who are profoundly deaf. - It has both external and internal components, with the external parts worn behind the ear and the internal parts surgically implanted. - Candidates for cochlear implants include adults and children over 12 months old with severe-to-profound hearing loss who get limited benefit from hearing aids. - The surgical procedure to implant the device involves making an incision to access the inner ear and inserting an electrode array to stimulate the auditory nerve. Extensive testing and rehabilitation is required post

1. DR. MAMOON AMEEN
`

2. INTRODUCTION
 The modern cochlear implant is an electronic device designed to convert environmental
sound into electrical impulses that are delivered along a multiple electrode array situated in
close proximity to the cochlear nerve.

3. INTRODUCTION
 Cochlear implants are the 1st true bionic sense organs.
 It is surgically implanted in the inner ear and activated by a device worn behind the ear.
 Cochlear Implants are not hearing aids.
 The Concept of Cochlear Implant is to bypass the damaged hair cells and directly stimulates
the nerve of hearing, allowing individuals who are profoundly deaf to receive sound.
 patient factors are more important than the device variations.

4.  1957 – Djourno & Eyeries – stimulated auditory nerve directly with current & the patient
reported a clear auditory percept.
 1961 – House & Doyle – put electrodes in scala tympani of 2 profoundly deaf adults & get
a clear auditory response
 1972 – First single channel cochlear implant developed.
History of CI

5. History of CI
 1984 – Cochlear Corporation introduced Multichannel Cochlear Implant
System
 1990 - FDA approved age for CI 2 years and up
 1998 - FDA approved 18 months and up
 2002 - FDA approved 12 months and up

6. Parts of CI
 EXTERNAL PART –
 1. Microphone
 2. Speech processor
 3. Transmitter
 INTERNAL PART –
 1. Receiver Stimulator
 2. Electrode Array

7. Types of CI

8. How CI works

9. COCHLEAR IMPLANT CANDIDATES
ADULTS
 Age – More than 18 yrs
 Bilateral severe to profound Sensorineural hearing loss.
 Must be Postlingual Deaf
 Little or no benefit from hearing aids.
 Sentence recognition test <50%
 No anatomical contraindication
 Lack of medical contraindication

10. COCHLEAR IMPLANT CANDIDATES
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 yo or 30% or less on
sentence recognition when >5 yo)
 Enrolled in aural/oral education program
 No medical or anatomic contraindications
 Motivated parents

11. COCHLEAR IMPLANT CANDIDATES
Children
 In cases of HL due to meningitis implantation should be considered before the age of
12 months.
 Auditory skills are generally assessed via parental history and administration of
validated questionnaires designed to gauge auditory-based responsiveness to speech
and sounds in a child's environment's

12. CONTRAINDICATION
 Deafness due to lesion in 8th nerve or brain stem
 CN 8 atresia
 Agenesis of cochlea: Michel deformity
 Active middle ear/mastoid infection
 Tympanic membrane perforation
 Severe organic brain dysfunction
 Severe mental retardation
 Psychosis
 unrealistic expectations
Absolute

13. WHICH EAR TO IMPLANT
 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

14. PRE-OP EVALUATION
 Detailed history and physical examination
 Collaborative effort involving patient, family, school, audiologist, speech /language
therapists and surgeons.
 Candidates must undergo audiologic testing and speech evaluation.
 Candidates are recommended to undergo a hearing aid trial to test whether hearing aids
are sufficient or an implant may be more beneficial.

15. PRE-OP EVALUATION
Psychological Assessment
 Performed to identify subjects who have organic brain dysfunction, mental
retardation, undetected psychosis, or unrealistic expectations.
 Information related to the family dynamics and other factors in the patient’s milieu
that may affect implant acceptance and performance are assessed

16. PRE-OP EVALUATION
Audiological assessment
 PTA
 Speech audiometry
 Aided audiometry
 ABR
 OAE

17. Radiological assessment
 Detect anomalies of bony labyrinth
 Narrow IAM
 Enlarge vestibule aqueduct
 Facial nerve dehiscence
 Low laying dura
 High jugular bulb
• Detect labyrinthine ossification
• Early fibrotic obstructions.
• Identification of cochlear agenesis
• Cochlear nerve agenesis
• Potency of cochlear duct
• Acoustic tumor
• CNS abnormalities
HRCT MRI

19. Enlarge vestibular aqueduct

23. SURGICAL PROCEDURE

24.  Done General anesthesia
without muscle relaxant
 IV antibiotics should be given
at least 20 minutes before skin
incision.

25.  Templates used to outline the position of
BTE processor ,internal receiver
 Space b/w Speech processer and receiver
stimulator template 15 mm

26.  Standard Postaurcicular incision with
posterosuperior extension marking
 Infiltration planned incision with
lidocaine /epinephrene

27. The skin and subcutaneous tissue are incised down
to the level of temporalis fascia superiorly and
mastoid periosteum inferiorly

28. Skin elevated off the periosteum and temporalis muscle

32. • Complete mastoidectomy is performed
• Once mastoid antrum is entered LSSC identified and
drilling continuous anterosuperiorly until the body of
the incus is identified .

34. Using 1-3 mm diamond burr facial recess is curefully
saucerized with copious irrigation to avoid thermal injury
to facial nerve

38.  A dummy internal receiver is
used to mark out the
dimensions of the bony recess

41.  Cochleostomy is performed
 Using 1 mm diamond bur
,small cochleostomy is made
immediately anterior and
inferior to the round window
membrane
 This allows direct access to
the Scala tympani of cochlear
basal turn.

42. The internal receiver is then placed in the bony recess

43. • The electrode array is inserted into the
scala tympani of the cochlea
• Undue force should not be used during
electrode insertion to avoid electrode
kinking within the cochlea and
minimize insertional trauma to
surviving neural elements within the
cochlea.

45. The cochleostomy is then
plugged with small pieces of
temporalis muscle or fascia.

47. Wound is closed in layers

49.  Intraoperative measurement (neural-response telemetry and impedence testing )obtained to confirm proper
functioning of the device before or after wound closure
 All devices have telemetry programs that allow for measurement of electrode impedances and electrically
evoked compound action potentials.

50. Mastoid dressing is applied for 24 hrs

51. POSTOPERATIVE MANAGEMENT
 Can be discharge on the day of operation
 7 days oral antibiotic
 Mastoid dressing removed on 1st POD
 Initial follow up visit 1 week
 External device fitted 4 weeks after the surgery, programming and rehabilitation begin

52.  Mapping involves fine tuning the speech processor and setting levels of stimulation
for each electrode, from soft to loud.
 The patient is then trained in how to interpret the sounds heard through the device.
 The length of the training varies from days to years, depending on how well the
person can interpret the sounds heard through the device.

53. COMPLICATIONS

54. Early
 Facial N. Injury
 Alteration of Taste
 Infection
 Dizziness
 Wound dehiscence / Flap Necrosis
 Early Device Failure
 CSF Leak

55. WOUND DEHISCENCE / FLAP NECROSIS
 Flap Necrosis occurs due to aggressive thinning of flap – most serious complication & require
device removal.

56. Wound breakdown over internal receiver with early
extrusion of the device.

57. CSF LEAK
 Occurs frequently at the time of drilling tie down holes.
 Can also occur after opening of scala tympani in case of – modiolar defect. / Common
cavity deformity. GUSHERS
 Controlled by packing the common cavity with muscle.
 If still not controlled – Ear is closed by plugging the eustachian tube, filling the
middle ear & mastoid with fat and oversewing the Extn. Auditory canal.

58. LATE
 Extrusion / Exposure of Device
 Displacement of Electrodes
 Late device failure
 Otitis Media
 Meningitis

59. MENINGITIS
Cochlear implantation recipients are at high risk of developing Pneumococcal Meningitis.
Center for Disease Control made it mandatory for pneumococcal vaccination as follows
 All children < 1 yr. must receive 3 doses of Pneumococcal Conjugate (PEVNAR)
 child > 5yr should receive one dose of pneumococcal polysaccharide vaccine.
 Cochlear implant child > 2 yr who have received PEVNAR should receive one dose of pneumococcal
polysacharide vaccine.

60. Thank you