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Review article
Endocochlear
inflammation
in cochlear
implant
users:
Case
report
andliterature
review
Alice Benatti a,*, Alessandro Castiglione b, Patrizia Trevisi b, Roberto Bovo a, Monica Rosignoli c,Renzo Manarad, Alessandro Martini e
aOperative Unit of Otolaryngology and Otosurgery, Padua University, Via Giustiniani, 2, Padua, ItalybDepartment of Neurosciences, Padua University, Via Giustiniani, 2, Padua, ItalycENT Department, Audiology Service, Ferrara University, Cso Giovecca 203, Ferrara, ItalydNeuroradiology, Padua University, Via Giustiniani 2, Padua, ItalyeDepartment of Neurosciences, Operative Unit of Otolaryngology and Otosurgery, Padua University, Via Giustiniani, 2, Padua, Italy
International Journal of Pediatric Otorhinolaryngology 77 (2013) 885–893
A R T I C L E I N F O
Article history:
Received 7 January 2013
Received in revised form 7 March 2013
Accepted 10 March 2013
Available online 8 April 2013
Keywords:
Cochleitis
Endocochlear phlogosis
Implant complications
Granulating
labyrinthitis
A B S T R A C T
Objectives: Cochlear implantation is a relatively safe procedurewith a lowcomplication rate. Theoverall
rate of complications among cochlear implant patients ranges from 6% to 20%. Major complications are
those that are life-threatening or require surgery, whereas minor complications are those that can be
medically treated. Nonetheless, certain complications, even if highly rare, may require specific
investigations and treatments. Among these rare complications are those with endocochlear
involvement, such as cochleitis or labyrinthitis, with fibrosis or ossification that could lead to
explantation. The aims of the present study
were to report a particular case of post-operative cochleitis
and to review the rate of complications after cochlear implantation, emphasising those conditionswith
proven endocochlear involvement.
Methods: We refer to the case of an eight-year-old Ital ian boy affected
by the sudden
onset of
headache,
ipsilateral
otalgia and facial
paresis, who presented to our clin ic for inexplicable
worsening of the performance of his implant and his residual hearing, six years after surgery.
A
complete
investigation including (clinical history,
routine, autoimmune
and serological bloodtests, electrophysiological measurements
from the cochlear
implant and neuroimaging) was
performed and is herein
described.
Additionally, a comprehensive
review
of the literature was
conducted using internet search engines; 274 papers
were selected,
88 of which were best suited to
our purposes.
Results: In our case, the progression of the symptoms and the performance decrement required
explantation,
followed by a complete
recovery. Reviewing the literature revealed only three reports
concerning
cases of proven
endocochlear phlogosis that required revision surgery.
Wound swelling/
infection and vertigo remain
the two most common complications of cochlear implantation. Failure
of the device
is the third most frequent complication (10.06% of all complications and 1.53% of
cochlear implantations).
Other rare conditions (such as granulating labyrinthitis with cochlear
fibrosis, ossification and erosion, silicone
allergy and the formation of a biofilm around the internal
device) are possible and unpredictable. Although
rare (approximately 1%), such
cases may require
explantation.
Conclusions: Despite efforts by both surgeons and manufacturers, device-related and surgical
complications still occur. These and other rare conditions demand specific management, and their
frequency may be underestimated. Further studies are needed to assess more realistic rates of complications and devise more efficient strategies for early diagnosis and treatment.
2013
Elsevier Ireland Ltd. All rights reserved.
* Corresponding author at: Operative Unit of Otolaryngology and Otosurgery, Giustiniani, 2, Padua 35128, Italy. Tel.: +39 339 6657486; fax: +39 049 821 1994.
E-mail addresses: [email protected] (A. Benatti), [email protected] (A. Castiglione), [email protected] (P. Trevisi),
[email protected] (R. Bovo), [email protected] (M. Rosignoli), [email protected] (R. Manara), [email protected] (A. Martini).
Contents
lists
available
at
SciVerse
ScienceDirect
International Journal of Pediatric Otorhinolaryngology
jo urn al hom ep ag e: www.els evier . c om/locat e/ i jp o r l
0165-5876/$ – see front matter 2013 Elsevier Ireland Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.ijporl.2013.03.016
http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://www.sciencedirect.com/science/journal/01655876http://www.sciencedirect.com/science/journal/01655876http://www.sciencedirect.com/science/journal/01655876http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://dx.doi.org/10.1016/j.ijporl.2013.03.016http://www.sciencedirect.com/science/journal/01655876mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://dx.doi.org/10.1016/j.ijporl.2013.03.016
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failure, dizziness/vertigo and infections represent the most
common complications (Table 2); however, certain complica-
tions may require specific investigations and treatments [6,41–
44].
Such cases are very
rare
and not usually reported in
casestudies; they include (Table 3) [10,45–60]: cochleitis, granulating
labyrinthitis, pneumocoele, pneumolabyrinth, surgical emphy-
sema, particular malpositioning or migration, biofilm array
infections and allergic reactions to internal device [43,61–74].
Although these are rare complications, they should be considered
as major complications because explantation may be required
[61,62]. As a consequence of pathological and inflammatory
processes, cochlear erosion [75], fibrosis and/or ossification may
occur, leading to device malfunction, extrusion of electrodes or
displacement of the intracochlear array, with unpredictable
consequences for the patient’s health and the performance of the
implant [63,76–80].
The aims of this study were to review the complication rate
after
cochlear
implantation
and
to
investigate
the
causes
of
unexpected clinical manifestations in an eight-year-old Italian boy
six years after cochlear implantation surgery, who was charac-
terised by headache, ipsilateral otalgia and facial paresis and
worsening
of
his
residual
hearing
and
the
performance
of
hiscochlear implant.
2. Materials and methods
2.1.
Clinical,
audiological
and
genetic
data
A detailed family and clinical history was obtained from the
young patient and his parents. Acquired and environmental factors
that might be related to hearing loss were investigated. A complete
audiological evaluation was performed using micro-otoscopy,
pure-tone (250–8000 Hz) audiometry to evaluate air and bone
conduction, speech audiometry to determine the speech recogni-
tion threshold and impedancemetry (tympanometry and acoustic
stapedial
reflexes).
Other
clinical
data
were
collected,
including
Table 2
Complications after/during cochlear implant surgery. The percentages refer to the total number of cases for which data analysis was possible (the studies with unspecified
and/or unavailable data were excluded from the total number of cases); % = percentage of total complications (1083, including unusual complications); %* percentages of total
cochlear implants (7132).
Type of complication No. % (of 1083 complications) %* (of 7132 cochlear implants)
Wound complications 223 20.59 3.13
Infections,
swelling,
haematoma,
suture
rupture
153
14.13
2.15
Subcutaneous haematoma, seroma, emphysema 57 5.26 0.80
Keloid 11 1.02 0.15
Thin
flap
2
0.18
0.03Equilibrium disorders 113 10.43 1.58
Vertigo 111 10.25 1.56
Nystagmus 1 0.09 0.01
Neuritis, labyrinthitis 1 0.09 0.01
Device complications 311 28.72 4.36
Failure 109 10.06 1.53
Gain
reduction,
Absence
of
stimulation
57
5.26
0.80
Infections 4 0.37 0.06
Malpositioning, migration, kinking 102 9.42 1.43
Extrusion
39
3.60
0.55
Leaks 90 8.31 1.26
Gusher 62 5.72 0.87
Csf (cerebrospinal fluid) 14 1.29 0.20
Fistula 9 0.83 0.13
Dural tear 4 0.37 0.06
Rhinoliquorrea 1 0.09 0.01
External, middle ear complications 92 8.49 1.29
External, media otitis, tympanic membrane perforation 58 5.36 0.81
Cholesteatoma 13 1.20 0.18
External
auditory
canal
injury
6
0.55
0.08
Acute otomastoiditis 14 1.29 0.20
Pocket retraction 1 0.09 0.01
Peripheral nerve complications 115 10.62 1.61
Temporary facial nerve palsy 46 4.25 0.64
Permanent facial nerve palsy 12 1.11 0.17
Facial stimulation 20 1.85 0.28
Chorda tympani injury 20 1.85 0.28
Change in taste 3 0.28 0.04
Post-operative pain, transient neuralgia 10 0.92 0.14
Alteration
in
facial
sensibility
4
0.37
0.06
Other 63 5.82 0.88
Worsening/increase/onset of tinnitus 16 1.48 0.22
Haemorrhage
13
1.20
0.18
Unspecified intraoperative complications 13 1.20 0.18
Cerebritis (1 case)/meningitis (7 cases) 8 0.74 0.11Non user 5 0.46 0.07
Respiratory distress, laryngospasm 3 0.28 0.04
Ocular disorders 2 0.18 0.03
Hypertension 1 0.09 0.01
Burn
1
0.09
0.01
Tachycardia, hyperthermia 1 0.09 0.01
Abdominal distension 1 0.09 0.01
Unusual
complications
(Tab
3)
76
7.01
1.07
Total 1083 100 15.19
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routine, autoimmune and serological blood tests, evaluation of the
thyroid and renal functions, electrophysiological measurements
from the cochlear implant and neuroimaging of the temporal bone.
Behavioral audiometry and auditory brainstem response (ABR)
testing were useful to define the clinical indications for a cochlear
implant at the age of 2 years, when he underwent the first
implantation surgery (2006). Direct sequencing of the GJB2 gene
was also performed to investigate the genetic cause of his hearing
loss.
2.2. Neuroimaging
Axial and coronal imaging with a high resolution computed
tomography (HRCT) scanner and a 1.5-tesla magnetic resonanceimaging (MRI) system was repeated during this young patient’s
life. In 2006, the patient underwent preoperative HRCT and MRI
scans for diagnostic and surgical purposes. In 2012, due to the
onset and progression of his symptoms, two temporal bone HRCT
scans were conducted, one month apart. He also underwent an MRI
of the temporal bone 24 h after explantation surgery for diagnostic
and prognostic purposes.
2.3. Literature review
A complete review of the literature was conducted using
computer search engines and internet databases; the search terms
‘fibrosis’, ‘ossification’, ‘cochlear implant’, ‘complications’, ‘cochlei-
tis’
and
‘labyrinthitis’
were
combined
as
follows:
‘(fibrosis
orossification) and (cochlear implant)’, ‘(cochleitis or labyrinthitis)
and (cochlear implant and/or complications)’. A second search was
performed using a combination of the search terms ‘cochlear
implant’ and ‘complications’. The English, Italian, Spanish, German
or French language articles were retrieved and included in the
review they reported cases of particular interest or research
published between 1996 and 2012.
3.
Case
report
3.1. Clinical, audiological and genetic data
The patient is an 8-year-old Italian boy affected by profound
congenital
bilateral
sensorineural
hearing
loss
of
unknown
origin.
Born at term after a normal pregnancy from unrelated parents with
no familial hearing loss, he underwent a left cochlear implantation
(Nucleus Freedom Contour, CI24RE) at the age of two years (2006).
Pre-operative click-evoked ABRs for bilateral ear stimuli at a level
of 95 dB nHL (normal Hearing Level) were absent. No GJB2
mutations were found.
The operation was uneventful and all of the electrodes were
properly inserted through the cochleostomy, achieving good
impedance values. The electrically evoked compound action
potential (ECAP) thresholds were measured intraoperatively using
the neural response telemetry (NRT) capabilities of Cochlear
Corporation’s (Cochlear1, Lane Cove, New South Wales, Australia)
CI24RE-CA device. The correct array position was documented by
postoperative skull radiography. He obtained good results and hewas followed-up regularly without problems until December
2011, when the device was tested and all of the electrodes were
found to have low impedance values and normal NRT thresholds.
At that time, the pure-tone and speech audiometry (with cochlear
implant) results were within normal ranges. The pure tone average
(PTA0.5,1,2
kHz), the average of the pure-tone thresholds at 500 Hz,
1 kHz, and 2 kHz, was 25 dB nHL and speech recognition at 30 dB
SPL (sound pressure level) was 80% of the words in an open set
(Fig. 1).
In February 2012, six years after the surgery, he presented to
our tertiary care hospital complaining of ipsilateral otalgia,
headache and cochlear implant ‘‘discomfort’’. No potential causes
were identified in the first examination; no signs of infection,
extrusion,
migration,
neuritis
or
vestibular
concerns
were
found.The results of micro-otoscopy and tympanometry were normal;
the acoustic reflex was absent as expected, due to the pre-existing
conditions. Nevertheless, a temporal bone CT scan was ordered and
steroid treatment (with partial symptom remission) was pre-
scribed. Technical analysis of the device was conducted, revealing
impedance variations of three electrodes and undetectable NRT
thresholds. The pure-tone audiometry results were still acceptable
with the cochlear implant (PTA = 32 dB nHL) but the young boy
presented severe tone-speech dissociation (Fig. 1). When provid-
ing a history, the patient and his parents did not refer to any
particular event, except for a violent head injury on the right side
that occurred three weeks before and a minor head injury on the
left side (the implanted side) that occurred a few days later. After
one
month,
he
returned
to
the
clinic
for
clinical
aggravation
with
Table 3
Unusual post-operative complications of cochlear implantation. The number of cases should be considered an underestimate.? = unavailable or unspecified data.
Unusual post-operative
complications
No. of
cases
Explantation Children
(18 years)
References
Cochlear complications
Pneumolabyrinth 3 None Rother et al. [65]; Ott et al. [69]; Hempel et al. [45]
Oesteolisys/erosion
5
4/5
1
Neilan
et
al.
[46];
Ho
et
al.
[71];
Cervera-Paz
&
Linthicum [75]; Doherty & Linthicum [84];
personal observation (2012, unpublished data)
Chronic
granulating
labyrinthitis
3
3/3
1
Levi
et
al.
[63];
Ho
et
al.
[62];
Bertuleit
et
al.
[61]Fibrosis/oesteogenesis 19 19/19 Côté et al. [47]
Silicone allergy/foreign
body reaction
25 14/25 3 Ciorba et al. [43]; Lim et al. [68]; Pirzadeh et al. [10];
Liu et al. [48]; Kunda et al. [70]; Migirov et al. [25];
Puri et al. [49]; personal observation (2012,
unpublished data)
Bacterial/fungal biofilm
formation
5 4/5 2 Neelam et al. [50]; Ruellan et al. [51]; Pawlowski et al. [52];
Cristobal
et
al.
[53];
Makarem
et
al.
[74]
Pneumocoele 4 None 2 2 Qiu S. et al. [64];
Epidural/subdural haematoma 4 None 1 Gosepath et al. [54]; Sunkaraneni et al. [55]; Dodson et al. [21];
Stamatiou
et
al.
[56]
Misplacement into the
carotid canal
8 8/8 1 1 Nevoux et al. [66]; Son et al. [57]; Tange et al. [58];
Gastman et al., [59]; Jain & Mukherji [60]; personal observation
(2012, unpublished data)
Total (%) 76 52/76 (68.42% of 76) 4 (?) 12 (?)
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fever (38.5 8C) and hyperemia of the external auditory canal and
cheeks. The patient was treated with the oral nonsteroidal anti-
inflammatory drugs cephalosporin and betamethasone for 7 days,
but they produced only a modest and transient benefit.
Given the fluctuating course of the symptoms, the patient
continued steroid therapy, 30 mg of Deflazacort per day, and
experienced partial improvement, but the hearing threshold of his
implant gradually worsened (Fig. 1).
After approximately one month, the patient had thinning or
disruption of the posterior wall of the external auditory canal with
reacutisation of symptoms, likely due to contact with a part of theinternal device array causing a ‘‘granuloma’’ of approximately
2 mm in diameter in the posterior wall of the external auditory
canal, near the annulus.
A few days later, the patient developed acute left facial nerve
paralysis (grade III on the House-Brackmann scale).
Technical analysis of the device revealed high impedance of 3
apical electrodes (20, 21 and 22) and basal electrode 1. The
external device functioned normally. Subsequently, an integrity
test on the CI24RE cochlear implant was performed by Cochlear
Italia SRL and it was concluded that the receiver–stimulator and all
of the electrodes were functioning within the specifications
(Normal Device Function) according to the ‘‘European consensus
statement on cochlear implant failures and explantations’’ [81].
The
results
of
the
blood
tests
were
all
within
the
normal
rangeswith the exception of the serum biochemistry, which showed an
increase in acute-phase reactants and the presence of IgM and IgG
specific for paramyxovirus type 1 that became negative to
subsequent one month control, exception for (obviously) IgG.
The worsening of his clinical condition, with left facial paralysis
grade IV, fever and persistent tone-speech dissociation, led to
hospitalisation for the removal of the internal device.
The presence of a small granuloma, most likely due to the array
having rotated, was confirmed intraoperatively; the inflammatory
reaction was essentially limited to the external auditory canal,
with no evidence of middle ear involvement.
After surgery and antibiotic therapy, complete regression of the
symptoms was achieved. A temporal bone MRI was performed 24 h
after
the
explantation
to
evaluate
the
inner
ear
and
the
VII/VIII
nerve complex. Histological examination confirmed the presence
of fibrotic tissue around the array. Two months later, the patient
underwent a right cochlear implantation without complications.
3.2. Neuroimaging
Temporal bone MRI and CT scans conducted in 2006, before the
first cochlear implantation, were normal with the exception of
mild plagiocephaly that was clinically insignificant. In 2012, two
months after the onset of symptoms, the patient underwent
another CT scan of the temporal bone, without contrast, whichshowed the following: (1) normal post-surgical anatomy and
correct array positioning; (2) presence of phlogistic material in the
left mastoid air-cells with preservation of the trabecular bone
microarchitecture and (3) presence of a granuloma in the posterior
wall of the external auditory canal, near the tympanic membrane,
with partial bone erosion (Fig. 2). No other significant alterations
were observed. Because his clinical condition worsened and his
facial nerve paralysis was aggravated, with both refractory to the
usual therapy, a HRCT exam was repeated one month later,
confirming the previous findings and showing a slight improve-
ment of the radiologic inflammatory signs. However, the HRCT
scans revealed hyperdensity in the left cochlea, likely attributable
to the initial fibrosis/ossification of the basal and apical turns
(Fig.
3).The post-explantation MRI revealed (Fig. 4) left cochlear
ossification and fibrosis with partial involvement of the internal
auditory canal. The VII/VIII nerve complex was not clearly visible in
the distal portion of the internal auditory canal.
4.
Discussion
A total of 274 reports were including in our metanalysis, 88 of
which best matched our purposes. Most of them referred to the
common or predictable (even if rare) complications of cochlear
implant surgery (Tables 1 and 2) and lacked insight into the
aetiology and management of particular cases because they
focused on the occurrence and classification of major and minor
complications
[6,41–43].
The
collective
data
confirmed
the
Fig. 1. Audiological data before explantation surgery. Tonal and speech audiometry showed the constant decline of implant benefits compared to the good performance
demonstrated at the end of 2011; (a) tonal audiometry results with the left cochlear implant (open set) and residual hearing without the cochlear implant (headphones); (b)
speech audiometry results with the left cochlear implant, using an open set of words, revealed an SRT equal to 25 dB SPL before the onset of symptoms, with worsening
performance in subsequent tests, so that there was a severe discrepancy between the tonal and speech audiometric results (SRT = Speech Recognition Threshold, the lowestlevel at which the speech signal can be correctly identified 50% of the time).
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complications rates reported in single studies. Device failure
remains the third most frequent complication (10.06% of the total
complications and 1.53% of the complications of cochlear
implantation) after wound-related complications and vertigo
(Table 2). However, these last two complications (vertigo and
wound involvement) are usually temporary and medically
treatable, whereas device failure necessitates surgical revision. It
can be deduced that device failure is the principal cause of
explantation/reimplantation (Table 1). Vertigo is most likely due to
surgical trauma to the vestibular labyrinth: its residual function
causes equilibrium disorders, which generally are self-limited and
resolve within a few weeks, as occurs in other vestibular disorders.Permanent facial palsy is a very rare complication (0.17%), most
likely due to intraoperative monitoring of the intratympanic and
mastoid portions of the facial nerve. In addition, the non-users (the
implant recipients who do not use them) are very rare (0.07%),
underlining the benefit and usefulness of cochlear implant, even if
it is possible that they are not always included in case studies on
post-operative complications. Cerebritis (1 case) and meningitis (7
cases) have an occurrence rate of 0.01% and 0.10%, respectively
(Table 2); nevertheless, the risk of meningitis among implanted
patients (100/100,000) is higher than that of the general
population (1.38/100,000) [82].
The particular cases reported in single papers range from simple
wound infection to meningeal involvement without distinction
being made between endocochlear or extracochlear complications[43,64–74]. Pneumolabyrinth, pneumocoele and epidural or
subdural haematoma appear to not require explantation
(Table 3). Only three reports [61–63] discovered in our literature
search involved proven endocochlear phlogosis in cochlear
implant users that resulted in explantation, of which two
[61,62] concerned fibrotic and oesteogenic processes (Tables 2
and 3). It is interesting that endocochlear involvement was usually
preceded or accompanied by bone erosion in the external auditory
canal [61–63].
In summary, our case report describes a late post-operative
complication leading to explantation because of extensive
cochlear involvement with fibrosis and ossification and, conse-
quently, malfunction of the implant. The clinical, neuroimaging
andsurgicalfindings
suggesteda
secondary
inflammationprocessof unknown origin with endocochlearand internal auditory canal
phlogosis. Consequently, granulating formations in the middle
and inner ear gave rise to partial erosion of the cochlea and
massive fibrosis/ossification of the basal and apical turns.
Contralateral cochlear implantation (Nucleus Freedom Contour)
was performed 2 months after the explantation (5 months after
the onset of symptoms). This operation was uneventful and all of
the electrodes were properly inserted through the promontorial
cochleostomy, achieving good impedance values and NRTthresh-
olds. Subsequently control showed a quick recovery to implant
benefits (Fig. 5). The correct array position was documented by
postoperative skull radiography.
Fibrotic and oesteogenic processes subsequent to inflammation
of
the
labyrinth
are
well
known
events
occurring
after
meningitis
Fig. 3. The second temporal bone HRCT scan showed: (A and B) slight improvement
of the radiologic inflammatory signs and (C and D) hyperdensity of the cochlea
likely
attributable
to
the
initial
fibrosis/ossification
of
the
basal
and
apical
turns.
Fig. 4. A temporal bone MRI performed 24 h after explantation revealed: (A–C)
cochlear ossification and fibrosis with partial involvement of the internal auditory
canal (white arrowheads); (C and D) reactive tissue formation in the mastoid with
air-fluid levels in the surgical cavity (white asterisk). The integrity of the explanteddevice was tested by the manufacturer and it was reported to be normal.
Fig. 2. Axial temporal bone HRCT scans showing the array position and the
phlogistic findings in the mastoid and external auditory canal. (A and B) There is no
evidence of electrode extrusion or migration; (C) a granuloma and adjacent eroded
bone (white arrow) are present in the posterior wall of the external auditory canal,
near
the
tympanic
membrane;
(D)
the
mastoid
air-cells
are
full
of
phlogisticmaterial.
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or during otosclerosis [76–79]. It is well known that fibrotic
phenomena occur near the array, but the cochlear abnormalities
induced by an implant are mainly of little clinical significance and
do not compromise the device’s functions [80,83–86]. While
middle ear infections can lead to meningitis, in this case, the
patient never showed the pathognomonic symptoms of meningitis
or mastoiditis. Therefore, his endocochlear involvement seems
more likely to be due to (unpredictable) reactive processes that are
very similar to a foreign body reaction, which was initiated and
sustained by traumatic events [75]. In our case, a manufacturer’s
report to rule out direct damage of the device causing its failurewas obtained from Cochlear Italia SRL. Furthermore, his para-
myxovirus infection may have provoked phlogistic activity
resembling an autoimmune cross-reaction [87,88], which would
explain all of the early and late symptoms. It is also possible that
those events can be attributed to predisposing conditions.
The impedance of the most apical and basal electrodes was
high, which mimics in implanted patients [85] the evolution of the
oesteodystrophic process in patients affected by otosclerosis [89–
93]. It is important to note that if predisposing conditions are
identified, they should be investigated prior to surgery.
5.
Conclusions
Cochlear
implantation
is
a
relatively
safe
procedure
with
acomplication rate of 6–20%. The frequency of complications has
consistently declined over the last 15 years settling and, to date, is
approximately 15% among cochlear implant patients. Reviewing
the literature (Tables 2 and 3) revealed that the majority of
complications are minor ones that do not affect the final outcome;
however, the classification criteria used to define minor and major
complications may be different. Furthermore, inner ear malforma-
tions or comorbidity may increase the risk of complications (such
as meningitis or gusher) [20], and the length of the follow-up
period may influence the reported occurrence rates. For these
reasons, the reported percentages of complications can vary widely
among the studies.
Unusual complications are rare and unpredictable situations
that
must
be
considered
major
complications
because
they
usually
require revision surgery (Table 3). Although massive fibrosis and
ossification of the cochlear lumen is a rare complication after
cochlear implantation, explantation may be required in such cases,
with specific treatment being administered to counteract the
pathophysiological process and reduce the overall symptoms.
The pathophysiological mechanisms underlying acquired or
congenital factors that constitute, in selected cases, a contraindi-
cation to bilateral cochlear implantation need to be identified.
Further studies are necessary to manage the events similar to those
of the case presented here, which may have resulted from
predisposing conditions, and to refine diagnostic procedures andtreatment options.
Consent
Written informed consent was obtained from the family
according to current national rules and laws for publication of
this case and any accompanying images.
Competing interests
The authors declare that they have no competing interests.
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