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Pediatric Cochlear Implantation
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
15 sections · 191 slides
Overview
- Preoperative medical and imaging evaluation Candidacy criteria and age of implantation Bilateral implantation and single-sided deafness Auditory neuropathy spectrum disorder Surgical technique, step by step Complications, outcomes, hearing preservation
- CI benefits bilateral severe-to-profound SNHL SNHL = sensorineural hearing loss Only ~50% of eligible US children receive one European uptake exceeds 90% Regional variation is marked
Preoperative evaluation
- Medical: history, examination, aetiology Surgical: anatomy and access to the cochlea Audiological: degree of loss and aided benefit All three must support candidacy Aetiology often predicts outcome
- Complete history and physical examination Birth history and perinatal events Immunization history Family history of hearing loss Otologic history Aim: identify the aetiology of the loss
- Prematurity, low birth weight, low APGAR Anoxia, intubation, NICU stay Aminoglycoside or furosemide exposure Hyperbilirubinemia, sepsis Meningitis and mumps
- Drug abuse, alcohol, thalidomide, methyl mercury TORCH infections implicated T: toxoplasmosis O: other, including varicella and syphilis R: rubella; C: cytomegalovirus; H: herpes
- CMV = cytomegalovirus Most common nongenetic cause of pediatric SNHL Universal targeted CMV screening proposed Paired with timely hearing evaluation May yield substantial benefit
- High meningitis rates in children with hearing loss Reefhuis 2003: 30-fold pneumococcal meningitis risk Risk greater where an electrode positioner was used Immunization history is therefore mandatory
- Route of infection to the inner ear
- Cochleovestibular malformation raises meningitis risk CSF = cerebrospinal fluid 32% of inner ear malformations leaked at surgery Leak noted intraoperatively at implantation
- Cochleovestibular anomaly on CT and MRI
- CDC ACIP guidance for implant recipients Under 2 years, unvaccinated or under 3 PCV doses: give two doses of PCV15 or PCV20 PCV = pneumococcal conjugate vaccine If no PCV20 and not immunocompromised: one dose PCV20 or PPSV23
- No prior PPSV23: give one dose PCV20 or PPSV23 PPSV23 = 23-valent pneumococcal polysaccharide vaccine PCV20 used: pneumococcal course complete PPSV23 used: repeat dose at 5 years
- Hib series only for children under 5 years Immunity presumed in older children CDC: complete immunizations 2 weeks before surgery UK MHRA: do not delay CI for immunization No human data link vaccination to CI meningitis
- About 50% of pediatric SNHL is genetic Non-syndromic far more common than syndromic Ask directly about early-onset and congenital loss GJB2 (connexin 26) is the commonest cause Autosomal recessive severe-to-profound loss
- Excellent cochlear implant candidates Significantly better outcomes than acquired deafness Comparator: environmental or acquired aetiologies Supports genetic testing before implantation
- Pendred syndrome Waardenburg syndrome Usher syndrome Branchio-oto-renal (BOR) syndrome Jervell and Lange-Nielsen syndrome
- C: coloboma of the eye H: congenital heart defects; A: choanal atresia R: mental and/or growth retardation G: genital hypoplasia E: ear anomalies and/or deafness Variable outcomes from developmental delay
- Both cause retinitis pigmentosa Progressive blindness follows Implant before severe vision loss occurs Preserves the dominant remaining sense
- Prolonged QT interval and cardiac arrhythmias Syncope is the presenting event ECG for congenital SNHL of unknown cause If confirmed: cardiology review, family testing Consider pacemaker or defibrillator before CI Perioperative beta-blockade
- Required regardless of family history Performed before implantation Identifies other contributors to auditory delay Establishes a baseline for later comparison
- Affects ~30% of children with hearing loss Some centres resist implanting these children Concern: speech and language may never develop Corrales and Oghalai highlighted this resistance
- Boons: learning disability lowered receptive scores Measured at 1, 2 and 3 years after implantation Yet CI improved language acquisition overall Also speech intelligibility, social interaction Environmental awareness, adaptive behaviour
- Palmieri: DADQ in 50 candidates with disabilities DADQ = Deafness and Additional Disabilities Questionnaire Gains in physical, neuropsychological, social domains Gerard: APCEI scale in 89 implanted children APCEI: Acceptance, Perception, Comprehension, Expression, Intelligibility
- Oral communication may not develop Expect increased sound awareness Improved family activity and interaction Better social and personal interaction Greater environmental connectivity Improved quality of life
Imaging evaluation
- Detect cochleovestibular anomalies Confirm presence of a cochlear nerve Exclude retrocochlear pathology Identify anatomical variants that hinder surgery Choose the side and confirm bilateral feasibility
- Present in 35-40% of pediatric CI candidates Bilateral in 65% of affected patients Some anomalies preclude implantation Most anomalous ears can still be implanted Exception: complete cochlear and labyrinthine aplasia
- Anomalous facial nerve in ~15% of anomalous ears May obstruct the traditional facial recess approach Anteriorly placed sigmoid sinus: 1.6% blocked exposure High-riding jugular bulb or diverticulum Aberrant or dehiscent carotid artery
- Incomplete partition type III Enlarged vestibular aqueduct Enlarged cochlear aqueduct All raise the risk of a CSF gusher Anticipate, prepare fascia and fat
- Post-meningitic labyrinthitis ossificans, commonest Suppurative labyrinthitis from cholesteatoma Otitis media, viral infection, septicaemia Rubella and mumps Osseous dysplasia such as Paget disease Temporal bone fracture sequelae
- Most commonly bilateral, severity asymmetric Obstruction begins in the basal turn Progresses toward the apex Onset unpredictable: weeks to years after insult Fibrosis precedes mineralization
- Both fibrosis and bone: loss of T2 hyperintensity MRI more sensitive for labyrinthitis ossificans MRI better for inner ear soft tissue anomalies CT may distinguish fibrosis from mineralization No difference shown in predicting abnormal anatomy
- MRI determines presence of the cochlear nerve Absent or deficient nerve in 18% with SNHL A common aetiology of pediatric SNHL Parasagittal oblique views through the IAC IAC = internal auditory canal
- Cochlear nerve aplasia on magnetic resonance imaging
- Dysplastic or hypoplastic nerve, radiological term Smaller than the facial nerve in the mid-IAC Distinguished from complete aplasia Different prognosis from an absent nerve
- Kutz: 7 with imaged absence, all implanted 6 gained speech detection or pattern reception 1 achieved closed-set speech recognition 2 with deficient nerves: closed-set word recognition Below the level of normal cochlear nerves
- Birman: 50 recipients, absent or hypoplastic nerve 27 of the 50 had developmental delay CAP = Categories of Auditory Performance 89% of dysplastic nerves reached CAP 5-7 47% of aplastic nerves reached CAP 5-7 CAP 5-7 represents some verbal understanding
Candidacy guidelines
- Lowering of the approved age for implantation
- Labelling is manufacturer-dependent HiResolution Ultra 3D: profound loss over 90 dB HL Nucleus, over 2 years: bilateral severe-to-profound Nucleus, 9 to 24 months: profound bilateral loss Aided word recognition limited to 30% or less
- From 7 months of age and older Bilateral severe-to-profound SNHL in low frequencies Aged 12 months to 5 years 11 months: bilateral mild-to-profound loss in low frequencies Low-frequency wording differs from other labels
- Many believe the criteria remain too strict Park: lowered age does not meet JCIH standards JCIH = Joint Committee on Infant Hearing Adult audiometric criteria are less restrictive Children held to a stricter standard than adults
- Carlson: retrospective review, CI aged 2 to 17 years Better than 70 dB HL pure-tone average in that ear Also under 24 months with 90 dB HL PTA Both groups scored over 30% best-aided PTA = pure-tone average
- 51 patients, mean follow-up 17.1 months Implanted ear: speech recognition up 62.8 points Bimodal condition: up 39.9 points Both improvements statistically significant Untestable children: 26.5 point language gain Authors: criteria should be reassessed
- Lovett: sought odds of 4:1 favouring bilateral CI Comparator: bilateral digital hearing aids Unaided PTA 80 dB HL or poorer in both ears Such children should be considered candidates
- Deafness after meningitis with cochlear ossification Implant as soon as medically safe And as soon as logistically possible Age criteria are set aside Rationale: ossification progresses unpredictably
- UHL = unilateral hearing loss SSD = single-sided deafness SYNCHRONY 2 and Nucleus approved from 5 years SSD: profound SNHL one ear, normal or mild other Aided word score 5% or less in the ear to be implanted Developmentally appropriate monosyllabic word lists
Age of implantation
- Earlier acquisition of receptive language skills Earlier mastery of auditory skills Superior speech production in some data Superior vocabulary development Comparator: older recipients
- Surgical and anaesthetic risks unique to infants Facial nerve lies more laterally Calvarium is thinner Underdeveloped sympathetic response Increased risk of bradycardia and hypoxia
- O'Connell: institutional and national databases Under 12 months versus 12 to 18 months No difference in 30-day surgical complications No significant difference in long-term complications
- Activation before 9 months studied separately Earlier access to sound achieved more auditory skills Compared with later activations Activation date, not surgery date, is the variable
- Dunn: 83 children, prelingual loss, CI before 4 years Language and reading equal before 2 years and 2 to 4 Attributed to duration of daily device use And to the richness of linguistic input Quality of maternal language input critical
- Effect of age at implantation diminishes over time Speech perception similar at 7, 11 and 13 years Prelingually deaf, implanted at 12: open-set speech Thresholds reported as low as 40 dB HL Do not refuse on age alone
- Degree of hearing loss Aetiology of the hearing loss Education received Speech therapy received Device used and therapeutic strategy
Bilateral implantation
- Better sound localization Better speech understanding in noise Reduced listening effort Improved quality of life In children: better speech in quiet and in noise Superior to unilateral CI with a hearing aid
- Simultaneous compared with sequential implantation
- Ramsden: no difference in complication rates No difference in immediate postoperative pain No difference in length of stay Total operative time shorter than sequential 26% of families still declined simultaneous CI
- Lack of acceptance of the child's deafness Waiting for future technologies Concerns about postoperative appearance Child unwilling to give up a hearing aid
- Chadha: bilateral early-onset deafness compared Sequential over 2 years apart versus simultaneous Noise and target speech spatially separated Simultaneous group scored significantly better Comparable to normal-hearing children
- Kocdor: 290 recipients under 18 years At least 12 months of listening experience Mean interdevice interval 3.4 years Ratio of best PBK scores, second side to first PBK = Phonetically Balanced Kindergarten word test
- No variation from gender, age, laterality None from intellectual disability, malformations None from comorbidity, onset, aetiology, ANSD Worse second-ear score with prolonged interval More pronounced in stable severe-to-profound SNHL Implant second device within 3-4 years
- Gordon and Papsin: 58 early-onset deafness Frequent users did better under 12 months apart Compared with intervals over 2 years Benefit still obtained up to 10 years later Never refuse a second implant on interval alone
- Friedmann: 25 sequential recipients First implant in childhood Second between 10 and 17 years of age Average interval 8.2 years Age at CI and interval did not predict outcome
- European consensus on bilateral implantation
- Santa Maria and Oghalai reviewed the literature Best practice: implant bilateral candidates together Consider surgeon experience Consider family and social situation Simultaneous is the ideal default approach
- Second implant gives substantial added benefit Emmett: CI and deaf education cost-effective Six lower- and upper-middle income African countries Summerfield: additional QALYs from bilateral CI QALY = quality-adjusted life year Bilateral CI probably cost-effective in the UK
Single-sided deafness
- Long known to have detrimental developmental effects Negative effect on social interactions Negative effect on language development Negative effect on academic performance
- Sangen: 21 children with SSD, aged 5 to 15 Each matched with two normal-hearing children Lower scores for language syntax and morphology Lower vocabulary scores than controls Tibbetts: resting-state functional connectivity MRI Different brain network interconnections
- 50 children presenting with SSD 32 qualified for CI, 20 implanted at publication Commonest cause: cochlear nerve hypoplasia or aplasia Second commonest: congenital CMV infection Varying gains in localization and speech in noise
- 4 children with SSD reported Thresholds above 90 dB HL in the implanted ear Contralateral air conduction no worse than 35 dB HL 3 had borderline indications but daily-life deficits Localization and speech in noise improved in all three
- Brown: prospective trial, 20 children Moderate-to-profound SNHL, word score under 30% Normal hearing in the contralateral ear BKB-SIN used to test speech perception in noise Significant gains at 12 months in all three configurations Head shadow, summation and squelch
- Localization improved by 26 degrees at 9 months SSQ improved in all three domains SSQ = Speech, Spatial and Qualities of hearing scale Listening effort also improved Meta-analysis: 12 studies, 119 children Nearly 80% gained meaningful speech-in-noise benefit
- Brown included children as young as 3.5 years FDA approval begins only at 5 years Handicap is well documented, benefit substantial Further research needed for insurance coverage Goal: establish CI for SSD as standard of care
Auditory neuropathy spectrum disorder
- ANSD = auditory neuropathy spectrum disorder Speech reception disproportionately poor Poor relative to the pure-tone thresholds Absent ABR waveforms with measurable OAEs ABR = auditory brainstem response OAE = otoacoustic emissions
- Early on, CI was limited in ANSD More recent studies show improved performance Otoferlin (OTOF) mutation gives superior outcomes Otoferlin: synaptic transmission at the hair cell CI bypasses the defect, stimulates the nerve directly
- Pelosi: 26 ANSD patients, hearing aid trial 16 of them eventually received an implant Median device use 48 months 4 of 8 hearing aid users exceeded 60% open-set 6 of 16 implant recipients exceeded 60% Carvalho: 10 children, all improved after CI
Surgical procedure
- Sequence of the standard operation
- Most high-volume US centres operate as outpatients Nausea and vomiting: commonest reason to admit Liu: due to anaesthetic recovery, not surgery Most studies included children over 2 years 19% and 33% of parents preferred overnight stay
- Highly dependent on the implanting centre Most centres leave choice to patient and family Migirov: questionnaire to 429, 112 children replied Children influenced by other implant users Also by medical staff and religious considerations More so than adult recipients
- No double-blind study in otologic surgery Most surgeons give one intravenous dose Typically an antistaphylococcal agent Given 20 minutes before incision Literature remains inconclusive
- Basavaraj: 292 adult and pediatric implants Three incisions and three prophylaxis regimens C-shaped and extended endaural: more infections Postauricular incision: fewer infections 5- and 7-day regimens: higher infection rates Higher than a single antibiotic dose
- Incision should not cross the receiver-stimulator Early: inverted U-shaped incision Rationale: blood supply thought to come inferiorly Large C-shaped incisions used, rare flap necrosis Necrosis after previous mastoidectomy incisions Then inverted L or inverted J incisions
- Postauricular incision for right cochlear implantation
- Single- or double-layer flap may be raised Single layer: incise through periosteum to bone Elevate periosteum with overlying soft tissue Double layer: raise superficial layer first Leave mastoid periosteum intact beneath
- Anteriorly based mastoid periosteal flap Sutured back to its original position at closure Protects the electrode array in the mastoid cavity Must cover the electrode take-off point Ideally covers the mastoid cavity as well
- Place 2.5 cm behind the bony external canal Measured from the posterior canal border Prevents interference with an ear-level processor Historically a bony well was drilled Well stabilised the device, prevented displacement
- Young children have thin calvarium Sometimes only 2-3 mm thick Well leaves the implant resting on exposed dura A channel to the mastoid is also required Risk of dural tear, CSF leak, haemorrhage
- Fixation options for the receiver-stimulator
- Many surgeons now omit the well entirely Some drill a slight depression with a bony ridge Alternative: tight subperiosteal pocket, no fixation Shortens operative time Still firmly secures the receiver-stimulator
- Creation of a tight subperiosteal pocket
- Sweeney: 193 patients, 228 implants DSPT = direct subperiosteal pocket technique About 4 cm postauricular incision to periosteum Curved 7 mm square-tip Lempert elevator used Mean 18.9% reduction in operative time No migration; mean follow-up 18.1 months
- Orhan: 8 of 280 needed revision for migration Revision at mean 9 months, range 5 to 54 months Spontaneous bone forms around the device bed Reported at revision whatever the indication Be prepared to use a drill at revision surgery
- Papsin: silastic pedestal on the medial surface Increases force required to displace the implant Parkes: 2.5 mm linear groove for the pedestal Tie-down sutures through drilled holes Or to 3 mm self-drilling plating screws Miniplate, Gortex or AlloDerm strips also used
- Drill holes and screws risk intracranial injury Subdural injury possible CSF leak may result Postoperative intracranial haemorrhage reported Assess calvarial thickness before choosing fixation
- Mastoid cavity does not need to be large Avoid unnecessary saucerization Saucerization lets the array escape the cavity Identify the lateral semicircular canal and incus Then open the facial recess widely
- Mastoidectomy with facial recess exposing the cochlea
- Facial nerve lies more laterally in children Bielamowicz: recess width under 1 year measured Compared with 2-3 year olds and adults No apparent difference in facial recess width Remove bone medial and inferior for exposure
- McRackan: 46 pediatric versus 40 adult ears Model-based segmentation of high-resolution CT Significant differences in orientation between: facial recess, round window, external canal and the long axis of the basal turn
- Almost all anomalous nerves lie anteriorly, medially Just distal to the oval window they turn inferiorly Run into the hypotympanum Course just below or over the round window Absent from the posterior recess boundary An unusually large recess suggests anomaly
- Facial recess opened widely first Round window niche then identified Bony overhang often obscures the membrane Remove overhang with a 1 mm diamond burr Membrane must be visualised before opening
- Approaches to the scala tympani
- Cochleostomy performed through the facial recess
- Avoid monopolar cautery near the implant It can damage electronic components Some insert only after the device is secured Others insert first for a more atraumatic angle Unsecured device allows greater flexibility
- Lubricants such as hyaluronic acid may be used Theory: bone dust and debris float out Or ingress of debris is prevented Aim: minimise postoperative osteoneogenesis Older electrodes need special tools and orientation
- Direct the electrode tip inferiorly Along the lateral wall of the basal turn Some use the right hand for left ears And the left hand for right ears Optimises the insertion angle
- Insert slowly to minimise trauma If resistance is met, apply slow gentle pressure Incomplete insertion uncommon without anomaly In hearing preservation, stop at resistance Accept incomplete insertion to protect hearing
- Fascia and/or muscle placed over the opening Positioned at the round window or facial recess Secures the position of the electrode Provides a barrier to the middle ear Separates scala tympani from middle ear
- Allows real-time assessment of insertion Under 10 rad per minute from most units Patient exposure should be under 200 rads Average exposure time under 3 minutes Fishman: 9 patients, insertion achieved in all No electrode damage despite malformation
- Coelho compared common cavity cases With and without image guidance Half of unguided cases: suboptimal array placement Higher incidence of complications More extracochlear electrodes Fewer active electrodes at follow-up
- Close in layers whatever the approach Dissolvable packing lateral to the array Prevents a suture catching the electrode Palva flap covers cavity and electrode take-off Buried interrupted sutures re-approximate dermis Pressure dressing removed after 24 hours
Alternative surgical approaches
- Designed to avoid a mastoidectomy Electrode enters middle ear suprameatally Via a retroauricular tympanotomy Tunnel drilled posterosuperior to anteroinferior Begins just superior to the spine of Henle
- Kronenberg: 126 pediatric patients, from 11 months Average follow-up 22 months 188 children and adults reported overall No significant speech perception difference Four tympanic membrane perforations Postelmans: 104 patients, 3.7% major complications
- Jackler: blind dissection is required Insertion not along the axis of the basal turn Electrodes may lie in an external canal groove Uses skills otologists do not routinely practise Cautioned against implementation
- Facial recess or retrofacial route may be impossible After mastoidectomy, elevate a tympanomeatal flap Place the electrode through the aditus ad antrum Avoids the need for a suprameatal tunnel Preserves familiar otologic anatomy
- Indications: radical cavity, chronic infection Also CSF leak with cochleovestibular anomaly Blind sac closure of the external canal Eustachian tube packed, mastoid obliterated with fat All middle ear and mastoid mucosa removed Prevents electrode extrusion in an open cavity
- Coletti described a middle fossa route Cochlea approached from the floor of middle fossa Middle ear is not entered An option when the middle ear is unusable
The ossified cochlea
- About 5% of children with meningitis get profound SNHL Meningitis can cause rapid cochlear ossification Earlier CI improves speech intelligibility And improves sound localization Ossification may force incomplete insertion
- Ossified right cochlea on MRI and CT
- Open-set speech achieved with at least 10 electrodes Liu: 39 implanted after bacterial meningitis 19 of 39, 48.7%, had labyrinthitis ossificans Trend to better scores without ossification, p = 0.17 Both groups improved significantly after CI
- Begin the drill-out 1.5 mm inferior Landmark: the pyramidal process or stapes This exposes the scala tympani If the basal turn is ossified, drill the niche Extend into the basal cochlea for 8-10 mm
- Carotid artery lies just anterior to the basal turn A pick may be needed for remaining fibrous tissue Or a laser to tunnel out obliterating tissue Distinguish fibrous obliteration from bone Stay aware of depth and direction
- Partial insertion possible via drilled basal turn Or middle turn cochleostomy for a double array Incus and stapes removed for oval window access Cochleostomy just anterior to stapes annular ligament Cochleariform process is the superior limit
- Rasp or small diamond burr creates an apical tunnel Tunnel directed toward the tensor tympani Insertion anterograde with Cochlear devices Retrograde with MED-EL devices Perimodiolar trough if both scalae are ossified
- Standard facial recess approach first 1.5 mm diamond drill, 8 mm anterior-inferior tunnel Tympanomeatal flap raised, malleus removed Promontory flattened, cochleariform process removed 1 mm drill unroofs the tunnel 4 mm from the window Trough follows the modiolus, array fixed with bone wedges
- Four pediatric patients reported Two English speakers: open-set PBK 24% and 16% Two Portuguese speakers: limited open-set recognition Demonstrates feasibility, not equivalence Counsel families accordingly
Postoperative complications
- Early or late by time course Most literature uses minor versus major Minor: managed conservatively or minimal surgery Major: surgical revision or hospital admission Both schemes are used interchangeably
- Timing of complications after implantation
- Chorda tympani injured in 20% of cases Device failure in about 2% of all cases Inner ear malformations increase complication risk Commonest immediate problems: dizziness, vomiting
- Sivam: 579 pediatric implants, aged 1 to 17 Nausea and vomiting in 50% Dizziness in 32% Age 1 to 3 years: no excess complications Bilateral 30% versus unilateral 19% Highest rate at 13-15 years, 36%
- Farinetti: 235 children reviewed 10.2% had minor complications Acute otitis media commonest minor, 58.3% 4.7% had major complications Mastoiditis commonest major, 36.4% Adults 26.8% versus children 14.9%, p = 0.002
- Javia: 557 implanted children 24.2% had a ventilation tube at some point No difference in complication rates Googe and Carron: 248 implants reviewed Major 5.2%, minor 11.3% complication rates Tube history did not affect complications
- Raveh: 490 pediatric CI surgeries 3.5% developed acute mastoiditis All had myringotomy and intravenous antibiotics 8 of 13 needed surgical drainage For subperiosteal abscess or no improvement 7 required a tympanostomy tube
- American Academy of Pediatrics recommendation Intravenous antibiotics if AOM or meningitis AOM = acute otitis media Meningitis: vancomycin plus meropenem Meropenem covers Gram-negative bacilli AOM: ceftriaxone or cefotaxime
- Oral antibiotics acceptable for uncomplicated AOM Standard bacterial meningitis regimen for meningitis For example ceftriaxone plus vancomycin Meningitis at 30 days to 2 years postoperatively Most likely arises from acute otitis media
- Causes: dural tear from drilling a bony well Or from drill holes for tie-down sutures Or a gusher with modiolar defect or anomaly Manage with head elevation, passive suctioning Occlude the opening once flow slows If needed: overclose canal, fill with fat
- Walgama: 7 patients with exposed electrodes Five of the seven were children Two children needed revision surgery Both had destructive otologic comorbidities Three managed with oral and topical antibiotics Plus careful observation
- Displacement follows trauma or MR imaging Young: 11 children, 13 MRI studies Compression head wrap and sedation used Complications in 30.8% of studies Polarity reversed in 3, weakened in 1, displaced in 1 Occurred even imaging below the head
- Displaced cochlear implant magnet on scout radiographs
- Rarely repositioned manually at the bedside Usually requires surgery C-shaped incision posterosuperior to the device Identify the fibrous capsule, replace the magnet Non-magnet plug if further MRI is planned Imaging in situ avoids repeated surgery
Outcomes
- Waltzmann: 36 prelingual, implanted under 5 years All developed significant open-set speech recognition Robbins: 23 developed language at a normal rate Geers: 181 implanted before 5 years Over half matched hearing peers in English
- Fitzpatrick compared hearing aids with implants No difference in open-set speech recognition No difference in speech production Moderately severe to severe loss with aids scored better In vocabulary, language, phonological memory And in reading comprehension
- Younger at implantation, better the performance Tobey: later age raises probability of delay Continued language delays reported Specifically in grammar And in pragmatic domains
- Hodges: oral-only communication did better Compared with total communication Geers: oral environments gave more CI benefit Robbins: no difference between oral and total Evidence is not unanimous
- Hannover programme questionnaire study Children implanted between 1986 and 2000 Mean follow-up 17.8 years Age at implantation predicted auditory performance Education and occupation poorer than population norms
- CI enables participation in society Speech and language skills are acquired Unimplanted: gap to chronological age widens After CI: the gap remains constant Constant gap is the key concept
Hearing preservation
- Adult literature has more hearing preservation data Few children have a ski slope audiogram That pattern is ideal for hearing preservation Relative paucity of implanted pediatric cases Interest driven by expanding candidacy
- Brown: 31 patients aged 19 years and under Unaided threshold 90 dB HL or better At 250, 500 or 1000 Hz preoperatively Protocol: dexamethasone 0.25 mg/kg intravenously Cochleostomy, sodium hyaluronate, standard array
- Complete preservation: low-frequency PTA change under 10 dB Achieved in 45.2% of patients Mean audiometric follow-up 10.7 months Range 1 to 30 months 9 of 18, 50%, kept functional hearing Functional: 75 dB HL or better at 250-1000 Hz
- Skarzynski: 16-year-old boy reported Thresholds 10-30 dB HL up to 1500 Hz Profound loss from 2000 to 8000 Hz 24 mm electrode via round window, 18 mm depth Dexamethasone 0.1 mg/kg/day for 3-4 days Also dexamethasone into the middle ear
- Complete preservation 82.5% at 5 years Classification system of Skarzynski et al. Partial preservation 74.6% at 7 years Slow decline over time Authors: expand CI criteria for adolescents
- Bruce: 14 patients aged 10 to 18 years Recordable thresholds at 125, 250 and 500 Hz Arrays 20 to 31.5 mm in length 12 of 14 inserted via cochleostomy Insertion stopped at first resistance in all
- Mean follow-up 34 months Half lost under 10 dB HL at 125, 250, 500 Hz Measured within 6 weeks of implantation 7 of 10 with 2-year follow-up kept under 10 dB loss Residual hearing can be preserved and maintained
- Gantz: 10 children aged 12 to 16 months Nucleus Freedom in one ear Nucleus Hybrid S12 in the contralateral ear S12 is a 10 mm electrode array Apex spared for possible future therapies Results similar to age-matched standard arrays
- Carlson: 35 patients, 43 ears Preoperative low-frequency PTA 75 dB HL or better Low-frequency PTA averaged over 250-500 Hz 65% maintained functional low-frequency hearing Supports expanding pediatric CI candidacy
Conclusion
- Significantly improves speech perception Improves language acquisition For severe-to-profound bilateral SNHL Younger implantation, shorter deprivation Shorter deprivation, better the outcome
- FDA approves from 9 months, and 7 months by device Safety demonstrated under 9 months of age Warrants investigation of still younger implantation Sequential implants ideally within 2 years Consider a second implant in any potential beneficiary Simultaneous bilateral is the default ideal
- Candidacy criteria actively being challenged Residual low-frequency hearing and SSD investigated Technique largely unchanged: incision, access, fixation Popular: round window entry Popular: tight subperiosteal pocket Complications minimal, usually outpatient surgery
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