Cochlear implant mukace final

COCHLEAR IMPLANT
Dr. Mukesh Kumar Sah
MS (ORL- HNS), 3rd year resident
GMSM Academy of ENT – Head & Neck
Studies
MMC-TUTH, IOM

Roadmap
• Background and Introduction
• History of the procedure
• Components, Working Mechanism and Types
• Candidates selection
• Surgical aspect
• Post Operative Issues
• Results
• Bilateral implant
• Recent advances and future development
Dr. Mukesh Kumar Sah, Cochlear
implant/2017
2

Background
• Cochlear implantation a routine procedure
worldwide for the management of severe-
to-profound sensorineural hearing loss
• collaboration between engineers,
surgeons, scientists and the medical
community
• more than 5,30,000 recipient till JanuaryDr. Mukesh Kumar Sah, Cochlear
implant/2017
3

Introduction
• A cochlear implant is an electronic device,
that bypasses the damaged hair cells of
the cochlea and stimulates the auditory
nerve directly
• Electromechanical transducer
• First true bionic sense organs
implant/2017
4

Introduction
• Internal device-interfaced with the cochlear
nerve
• External device-uses a specific speech
coding strategy to translate acoustic
information into electric stimulation
implant/2017
5

History of the procedure
• 1957, Djourno and Eyries -activation of the
auditory nerve with an electrified device
provides auditory stimulation
• 1963, Doyle and Doyle - scala tympani
implantation
• 1972, House- first House/3M single-
channel implant
• 1984- Multichannel devices introduced
implant/2017
6

Pathology
• direct or indirect injury to the organ of Corti
• degeneration or dysfunction of the hair cell
system
• success of cochlear implantation -
surviving spiral ganglion neurons
• number of surviving neurons needed for
successful implantation remains unclear
• 10-70% of the normal 35,000-40,000 cells
(Seyyedi et al., 2014)Dr. Mukesh Kumar Sah, Cochlear
implant/2017
7

Pathology
• normally approx 35,000 nerve fibres and
minimum of 10,000 spiral ganglion cells
required for preservation of speech
recognition
(Otte et al., 1978)
• no significant correlation between total
spiral ganglion cells count
(Blamey , 1997)
• no relation with depth of insertion with
performance
implant/2017
8

Cochlear implant system
1. Cochlear system, --Cochlear Ltd of
Sydney, Australia
2. Med-El system, --Med El of Innsbruck,
Austria
3. Clarion system, --Advanced Bionics of
California, USA
implant/2017
9

Components of Cochlear
Implant
External part
1. Microphone
2. speech Processor
3. Transmitter
implant/2017
10
Pic: cochlearworld.com

Components of Cochlear
Implant
Internal part
1. Receiver/stimulator
2. Electrode array
implant/2017
11

implant/2017
12

Types of Cochlear Implants
• Single vs. Multiple channels
- Early implants-one electrode/one channel
- Recent ones-multiple electrodes(22),
multiple channels(4-8)
- Results of multichannel CI better than
single channel
(Waltzman et al.,1993)
implant/2017
13

Multichannel cochlear Implants
1. straight,flexible electrode arrays
2. Precoiled
• less traumatic
• focussed
(Gibson et al., 2006)
implant/2017
14

Types of Cochlear Implants
• Monopolar vs. Bipolar
- Monopolar-one ground electrode for all
- Bipolar-ground for each electrode is
adjacent to or few electrode away
implant/2017
15

Types of array
• Shortened array – deep insertion not
desired/possible e.g. cochlear ossification
• Compressed array- number same,
compact, can be used with cochlear
anomaly
• Split array- 2 separate electrode branches,
different area of cochleaDr. Mukesh Kumar Sah, Cochlear
implant/2017
16

Coding Strategy
• Method by which pitch, loudness, timing of
sound are translated into a series of electrical
impulses
 Simultaneous
Non-simultaneous
implant/2017
17

Coding Strategy
 Simultaneous
• activation of more than one electrode at
the same time
• Improved speech outcomes, a more
natural quality of sound
• Potential “channel interaction”
• Clarion® (Advanced Bionics Corporation,
Sylmar, Calif.)
implant/2017
18

Coding Strategy
 Non-simultaneous
• continuous interleaved sampling (CIS)
strategies stimulate each active electrode
serially
• each electrode stimulates a different
frequency within the cochlea, the cochlea
receives complete information about the
frequency composition of the incoming
signal
implant/2017
19

Nucleus 24 Cochlear Implant
System
• First to receive FDA approval
• Manufactured by Cochlear Ltd. Australia
• Most widely used
• Implant casing- Titanium
• 24 electrodes(2 ground electrodes)
• 3 speech-processing strategies
• Nucleus Contour electrode array- more
closely approximate the modiolus
implant/2017
20

Clarion Cochlear Implant
System
• Advanced Bionics, California
• FDA approval for use in adults and children in
1996 and 1997
• Newest version- Hi Resolution (HiRes) Bionic
Ear
• 16 channels of frequency/16 electrodes
• Speech Processing Strategy(CIS, SAS, MPS)
• Only CI capable of simultaneous stimulation of
multiple electrodes within the cochlea
implant/2017
21

Advanced Bionics implant
system
implant/2017
22

Med-El Combi 40+ Cochlear
Implant System
• FDA approval for use in adults and
children in 2001
• Has longest electrode array
• 24+1 additional ground electrode
• Ceramic casing
• Speech Processing Strategy(CIS, n-of-m)
implant/2017
23

Similarities between the three
CI Systems
• Multichannel stimulation
• Transcutaneous communication
• Integrity of intracochlear electrodes
monitored by telemetry
• Range of speech processsing strategy
• Programming of speech processor
• Cost
implant/2017
24

Candidate selection
• Initially- Postlingually deaf adults with no
improvement with hearing aids
• Neural plasticity- main factor to influence
candidacy
• Neural plasticity- ability of CNS to be
programmed to learn a task
• For auditory function neural plasticity:6-8
years
• For speech articulation: 2-3 yearsDr. Mukesh Kumar Sah, Cochlear
implant/2017
25

Candidacy categories
• Postlingual : acquired speech before becoming
complete deaf
• Prelingual : become complete deaf before
acquiring speech
 Primary: No other form of language acquired
 Secondary: signs to communicate
 Change over candidate: auditory skills using
hearing aid
• Perilingual : deafness acquired during speech
development
implant/2017
26

Post lingual candidates
• Post pubertal groups: excellent candidate
– No gross articulation changes even over prolonged
periods of deafness
– Errors: Inappropriate loudness, pitch changes, and
loss of intonation
• Prepubertal groups
– Articulations errors
implant/2017
27

Peri-lingual candidates
• Deafness at 2-4 years, lose memory of speech
within few months of deafness
• Difficulties similar to pre-lingual
implant/2017
28

Pre-lingual
• Primary Candidate: As early as possible,
teach the child to hear and speak( auditory
verbal techniques )
• Secondary candidate: Unlikely to get any
significant improvement in speech
intelligibility
• Change over candidate:
Excellent implantees
Auditory system primed
Neural plasticity remainsDr. Mukesh Kumar Sah, Cochlear
implant/2017
29

Adult selection criteria
• B/L severe or profound SNHL with PTA
>70dB HL
• Use of appropriately fitting hearing aids
• Aided scores on open-set sentence tests
of <50%
• < 50% correct responses to HINT
sentences in quiet
implant/2017
30

Adult selection criteria contd…
• No evidence of central auditory lesions or
lack of an auditory nerve
• Psychologically suitable
• No anatomic contraindications
• Medically not contraindicated
implant/2017
31

Paediatric selection criteria
• 12 months or older
• Bilateral severe-to-profound SNHL with
PTA of 90 dB or greater in better ear
• No appreciable benefit with hearing aids
(parent survey when <5 yr or 30% or less
on sentence recognition when >5 yr)
implant/2017
32

Paediatric selection criteria
contd…
• Must be able to tolerate wearing hearing
aids and show some aided ability
• Enrolled in aural/oral education program
• No medical or anatomic contraindications
• Motivated parents
implant/2017
33

Ear selection
• In earliest days of CI, worse ear chosen -
implantation destroys residual hearing
• Currently, better hearing ear (High residual
neural elements)
implant/2017
34

Ear selection contd…
• Duration of deafness
• Previous procedure
• Vestibular function
• Hearing aid beneficial on the contralateral
ear:
 If neither ear can continue to use a hearing aid,
then better ear or the ear recently deafened is
chosen
 If either ear can continue to use a hearing aid
equally well, we choose the ear to implant on the
basis of handedness, patient preference, orDr. Mukesh Kumar Sah, Cochlear
implant/2017
35

• CNS activation: functional MRI, and
refined cortical auditory electrophysiology
(Roland et al.,2001)
• Physical Characteristics: cochlea and the
auditory nerve, prior surgical procedures
(e.g., canal-wall-down mastoidectomy),
facial nerve anomalies, and chronic otitis
media
• All things being equal -right ear: possible
advantage of contralateral left-hemisphere
specialization for speech recognition
implant/2017
36

implant/2017
37

COM and Cochlear implant
• dry tympanic membrane perforation: first
stage myringoplasty followed by
implantation in 3 months
• cholesteatoma or an unstable mastoid
cavity: radical mastoidectomy and
obliteration followed months later by a
second-stage cochlear implantation
implant/2017
38

Pre-operative evaluations
• Clinical otological evaluation
• Audiologic exam with binaural
amplification
• CT scan/MRI of temporal bones
• Trial of high-powered hearing aids
• Psychological evaluation
• Blood tests and medical evaluation
• Any necessary tests to discover etiology of
hearing loss Dr. Mukesh Kumar Sah, Cochlear
implant/2017
39

Pre-operative preparation at our
centre
• Pre-op investigations
PTA
Tympanometry
OAE
ABR
Aided threshold
HRCT of temporal bone (cochlea, facial
recess)
MRI inner ear (IAM, auditory nerve, facialDr. Mukesh Kumar Sah, Cochlear
implant/2017
40

Pre-operative preparation at our
centre contd…
• Hearing aid/ Speech Therapy- Better
started 2 months prior to surgery
• Vaccinations- Pneumococcus,
Haemophilus, Meningococcus, Hepatitis B
• Admission 1 day prior
• Antibiotics
implant/2017
41

HRCT/MRI
implant/2017
42
Source: Shambaugh 6th ed.

Surgical procedure
• Prophylactic antibiotics, about 1.5-3 hours
• GA, supine with head turned to opposite
side
• Procedure
– Incision and skin flap
– Bony seat for receiver/stimulator
- Mastoidectomy(Drill facial recess)
– Cochleostomy for electrode insertion
- Secure receiver/stimulator with sutures
– Pack with fascia and close incision
implant/2017
43

Procedure
implant/2017
44

Procedure
implant/2017
45

Procedure
implant/2017
46

Procedure
implant/2017
47

Middle cranial fossa approach
• Colletti and colleagues
• Alternative to the transmastoid approach
• Deeper penetration with more extended
coverage of the length of the cochlear duct
• Avoid ossification limited to the basal turn of
the cochlea, the most common area of
ossification
• More risk associated, needs further study
implant/2017
48

Special Surgical Considerations
Cochlear dysplasia
• Less severe form- results excellent
• Michel’s deformity- contraindicated
• Possibility of facial nerve anomaly
• CSF gusher esp. with Large vestibular
aqueduct syndrome
• Tightly pack the electrode at the
cochleostomy with fascia.
implant/2017
49

Special Surgical Considerations
Cochlear ossification
• Split electrode arrays (Bredberg et al.,1997)
• Extensive drill-out procedure to gain
access to the upper basal turn (Gantz et al.,
1988)
• Insertion of the active electrode into the
scala vestibule (Steenerson et al.,1990)
• Compressed array ; double array can be
used
implant/2017
50

Early post operative
complications
• Wound infection- 3%
• Wound dehiscence esp. in children
• Postoperative bleeding or hematoma
• Flap necrosis – thin flap, wound infection
• CSF leak – Cochlear dysplasia
implant/2017
51

Early post operative
complications contd…
• Facial nerve paresis: 1 to 2%, anomalies
common with cochlear dysplasia
• Facial nerve stimulation (7-25%)
• Early Device Failure
• Balance disturbances: <10% patients
resolves within few weeks
• Meningitis: young age, cochlear dysplasia,
temporal bone abnormalities
implant/2017
52

Late post operative
complications
• Extrusion or exposure of the device:
suture lines as far as possible from the
edge of the implant
• Pain: periosteitis
• Displacement: physical injury
• Non users: secondary prelingual
candidate.
• Late device failure
implant/2017
53

Postoperative considerations
Device Activation/Hook up
• 2-4 weeks post operatively, when edema
subside
• The implant is connected to the external
component and tuned up
• Determine the stimulation mode: Monopolar,
Bipolar
• Initial programming: threshold level, most
comfortable loudness level, and uncomfortable
loudness level
• Objective methods to assess threshold – NRT,
implant/2017
54

Switch on
• Switch on is generally done by an
audiologist
• If can hear nothing:
Electrode array is misplaced
No spiral ganglion cell surviving
Young Children recognoizing the response
may be difficult
Device not functioningDr. Mukesh Kumar Sah, Cochlear
implant/2017
55

MAPPING
• After switch on
• The map is stimulation threshold and the
maximum comfort level of each electrode
• Can take several months before a stable
map is obtained
• Implant Evoked ABER: can be done prior
to switch on in very young children
implant/2017
56

Rehabilitation
• Necessary part of implantation
• Multidisciplinary, dedicated group necessary
• Needs differ depending on auditory experience
before deafness
• Prelingual - auditory and speech training
• Postlingual - auditory for complex skills
• Parents play critical role for paediatric patients
• Develop receptive and expressive language
skills
implant/2017
57

Results of Implantation
• Variability in outcomes primarily due to
patient factors
• Primary goal is improved speech
perception
• Measurement of hearing levels, speech
perception (Open or Closed –set test)
• Postlingual- achieve open-set
discrimination earlier
• Prelingual children continue to improve
over 2-5 yearsDr. Mukesh Kumar Sah, Cochlear
implant/2017
58

Factors that affect performance
• Hearing experience (e.g., amount of
residual hearing, length of profound
hearing loss, hearing history for each ear)
• Age at onset of profound hearing loss
(particularly if before the age 3 years)
• Experience with language before onset of
deafness
• Age at implant (particularly if 75 years old
or older)
implant/2017
59

Factors that affect performance
• Status of cochlea
• Cognitive/central abilities
• Motivation to hear
• Communication mode
• Length of cochlear implant use
• Aural/oral education
• Highly motivated patients/parents
implant/2017
60

Age factor
• <3.5 years regain normal latencies within 6
month. After 7 years, little plasticity
remains
(Sharma et al.,
2002)
• 90% of children implanted <2yr were
integrated into mainstream vs. only 20-
30% if implanted after age 4
(Govaerts et
al.,2002)
implant/2017
61

Age factor
• 54 children <4 years, 82% open-set
discrimination
(Gantz et al., 2002)
• 14 children implanted prior to age 3, followed for
2-5 years, all aspects of hearing improved, oral
language, attended regular school, open-set
discrimination
(Waltzmann et al.,
2002)
implant/2017
62

Device failure
• Causes:
 fractures or deformation of the ceramic or
titanium receiver/stimulator cases
 failure of the integrated circuit
 electrode breakage or short circuiting
• Manifestations:
 shocks
 intermittency of function
 the onset of unusual sounds.
implant/2017
63

Revision surgery
1. Device failure.
2. Technologically outdated device
3. The device becomes extruded or
exposed. Revision operation may or may not
require
4. The skin flap must be revised, usually
because it is too thick.
5. An additional procedure is being
performed in the area of the implant, for
example, auricular reconstruction
implant/2017
64

Cost
• In United States, cost range from
US$45,000 to US$125,000 (evaluation,
surgery, device, hospitalization and
rehabilitation)
• Warranty – Implanted components 10yr
and external components 3yr
implant/2017
65

Bilateral Cochlear Implants
• 1992: 0-1% and 2007: 14-15%
• 70% of bilateral CI usage is among 18
years and under age group
(Source: Cochlear Americas
estimates,2009)
implant/2017
66

• Advantages:
Improved hearing in quiet
Improved hearing in noise
Improved sound lateralization
Improved sound localization
Assurance that the “better hearing ear” is
implanted
Qualitative listening improvement (more
“balanced”; “richer quality”; more “confident”
feeling and less fatigued)Dr. Mukesh Kumar Sah, Cochlear
implant/2017
67

• Disdvantages:
Increased costs (2 devices, batteries, etc.)
Multiple pieces of equipment to manage
Surgical and medical risks
Future developments
No or limited “natural” hearing remaining
Challenge – Different processing strategies &
speech processors (with sequential bilateral CIs)
implant/2017
68

Follow up
• For Adults:
weekly adjustments of the MAP and
communication therapy for the first month
auditory training, speech, reading, music,
telephone use & communication strategies
• For children:
after the initial 3 month intensive period, every 3
months for the first year and every 6 months for
the second and third years; thereafter, annually
implant/2017
69

MRI after Cochlear Implantation
• contraindicated -potential for interaction between
the two magnets
• Four possible interactions:
1. movement of the stimulator/receiver or
electrode array,
2. generation of noxious or even injurious auditory
stimuli
3. generation of heat
4. demagnetization
• Nucleus device with a removable magnet
• MED-EL – MRI safe upto 1.5 TDr. Mukesh Kumar Sah, Cochlear
implant/2017
70

Recent advances
Combined Electrical and Acoustic
stimulation(EAS)
• patients with more residual hearing
• performance is expected to be better
• Basal end of the cochlea receives electric
signals complemented by acoustic signals
received at the apical portion of the cochlea
• Partial insertion of cochlear implants
• Intraoperative mapping
implant/2017
71

Combined Electrical and
Acoustic stimulation contd…
• shortened electrode arrays (24 mm for the
MED-EL device, 10 mm for the Nucleus
Hybrid device)
• electrode insertion as atraumatic as
possible
• “Softip” electrode array (Cochlear
Company)
• improved word understanding in noise and
better music appreciation
implant/2017
72

Future development
• Totally implantable devices
• Remote re-programming
• Delivering drugs or neurotrophic factors to
the cochlea and auditory system through
the intracochlear electrode
implant/2017
73

Auditory Brainstem Implant
• Deaf patients with damaged or missing
auditory nerve (cochlear nerve agenesis or
excessive ossification)
• ABI has an electrode carrier with 20 small
disc electrodes
• Inserted on to the surface of the cochlear
nucleus in the lateral recess of the fourth
ventricle, accessed through the foramen of
Luschka
implant/2017
74

Auditory Brainstem Implant
• Correct position of the implant verified by
eliciting EABR
• Outcomes with the ABI are not as good as
typical cochlear implant results
• Awareness of environmental sounds and
enhanced lip reading scores
implant/2017
75

Issues of deaf culture
Two camps with very different opinions:
There are those who see the CI as a gift and a
miracle that will enhance the quality of life
There are those who see the CI as a threat to
Deaf Culture and as a tool that considers
Deafness as a disability.
 Being Deaf is a birth right and not a disability.
A large portion of the Deaf Community sees the
CI as a threat to its very identity.
The implant perpetuates the idea that Deafness
is a disability that should be remediated
implant/2017
76

Conclusion
Cochlear implants are not experimental
Rehabilitation for severe to profoundly
deaf who doesn’t benefit from
conventional hearing aids
Provide high quality of sensation of
hearing
Further research improves implant
components and implant results
implant/2017
77

References
• Scott-Brown’s Otolaryngology, Head and Neck Surgery, 7th edition.
2008.
• Glasscock-Shambaugh Surgery of the Ear, 6th edition.2012
• Ear Surgery, W.B. Saunders Co., Philadelphia, 2000.
• Cochlear Implant: A short hand
• http://emedicine.medscape.com/
• http://www.uptodate.com
• https://en.wikipedia.org/wiki
implant/2017
78

Thank you
implant/2017
79

Cochlear implant mukace final

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Semelhante a Cochlear implant mukace final

Semelhante a Cochlear implant mukace final (20)

Último

Último (20)

Cochlear implant mukace final

Notas do Editor