Indicazioni all'impianto cocleare - parte 2
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Transcript of Indicazioni all'impianto cocleare - parte 2
Round window /Cochleostomy
Device Positioningdevice away from
processor
receiver/stimulator oriented differently in infants
Displacement Force CalculationA
P
L R
mg
the bed the device tied in
Tie-down – Devices with and without a Pedestal
Visualizing the Round Windowkey
to cochleostomy placement is finding landmarks every time
most important landmark is the round window
Visualizing the Round Windowhand position differs
on the left side
care with stapes tendon
Round Windowalways presentoverhangrelationship to oval
window is constant jugular bulbrolls away in
anomalies
round window
stapes tendon
jugular bulb
Common Cavity Right Ear
Round Window
cochleostomydirectionentry into the
scala tympani
Cochleostomy vs. Round Windowbone in round
window
steeper angle at first turn contact
hard to pack/seal right ear bone in hook region
Cochleostomy vs. Round Windowbone in round
window
steeper angle at first turn contact
hard to pack/seal
right ear
coch
leos
tom
yroun
d w
indo
w
Cochleostomy vs. Round Window bone in round window
steeper angle at first turn contact
hard to pack/seal
Preparing the Cochleostomy anterior to the
round window
as inferior as possible
look often
Cochleostomy with curved burs
Curved HS Neurotology Burs Coolant Wrap
Opening the Cochlea pick used in “soft”
technique
hearing preservation
Drilling the Cochleostomyright ear
target is scala tympani
enter cochlea expand in anterior
and inferior direction
slow speed drilling
Drilling the Cochleostomy target is scala
tympani
right ear
Drilling the Cochleostomy slow speed drilling
round off anterior and inferior edges (electrode is 0.8 mm)
flush out bone dust
Ideal Cochlear Entry Point
Photo courtesy CRC for Cochlear Implant and Hearing Aid Innovation, MELBOURNE
Access into Scala Tympani
scala tympani
scala vestibuli
modiolus
SEXN° AGE RANGE TYPE I.C.
148m 156f312 11m. - 16aa
Cochlear
Med- El
AB
MXM
CASISTICA CLINICAmarzo 2003 – dicembre 2011
Abnormal Cochleae
25% of anomalous cochleae have technical challenges at ORgushersanomalous VII n. anatomyproblematic exposure
Perilymph Gushers enlarged vestibular
aqueduct (VAE)
Perilymph Gushers enlarged vestibular
aqueduct (VAE)
common cavity deformity
Perilymph Gushers enlarged vestibular
aqueduct (VAE)
common cavity deformity
incomplete partition (IP-1)
Facial Nerve Anomalies common (14%) and
associated with: CC and HC anomalous stapes nerve can split proximally
facial nerve monitor essential
Problematic Anatomy
anteriorly displaced CN VII
prominent sinus pericrani
hypoplastic cochlea
Re-implantation device failure device infection
(leave array in cochlea if possible)
Re-implantation tips
be prepared to drill around cochleostomy
insert new array immediately old array removed
straight array narrower but more flexible
Choice of electrode array
Options
Pre-curved
Straight
Short
Long
Double or split
Indications
general use, atraumatic AOS insertion
incomplete partition
hearing preservation
apical stimulation
ossified cochleae
Conclusion
keys to success are:appropriate selection of the patientfixation of the receiver stimulatoridentification of landmarks for round
window/cochleostomycare with abnormal cochleaeappropriate selection of the electrode
CI is generally possible in cases with inner ear
malformations
Variable results (neural function) generally
satisfactory results
Surgical issues
Programming difficulties / facial nerve electrical
stimulation
Higher risk of post-op. meningitis
CONCLUSIONS 2
• surgical access
• CSF gusher (difficult to radiologically predict)• type of array • array placement misplacement in the IAC (++IP I, IP III, CC, CH)
Fenestral CSF fistula (++)CSF fistula at cochleostomy site (--)
Facial nerve anomaliesCochlear anomalies
Cochlear nerve aplasia-hypoplasia is not uncommon(unilateral ++)
Cochlear nerve aplasia associated to a normal labirynth is possible
A severely narrowed IAC (2 mm) indicates a severe hypoplasia of the
cochleo-vestibular nerve, but not a sure absence of the cochlear
nerve (if the cochlear duct is present and the labirynth is
malformed, the possibility of a functioning cochlear nerve is higher)
A normal IAC does not garantee the presence of a normal cochleo-
vestibular nerve (unilateral cases, parasagittal reconstructions)
The outcome after CI in pts with aplasia-hypoplasia of the cochlear
n. are generally scarce
Thank You !!!
Azienda Ospedaliera di Rilievo Nazionale
Santobono – Pausilipon NAPOLI