Oticon Medical Neuro User manual

Magnetic Resonance Imaging (MRI) Exam
Instructions for Use
Neurelec S.A.S
2720 Chemin Saint Bernard, 06220 Vallauris  France
TEL : [phone], FAX : [phone]
0459
(2015)
Neuro – The Cochlear Implant System

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Table of content
MRI medical exam ....................................................................................................3
A. MRI exam with implanted magnet in place (at 1,5 Tesla) ........................................... 5
B. MRI exam with magnet removal (3 Tesla) ..................................................................6
C. Dummy removal and magnet replacement ..............................................................11
D. Magnet replacement...............................................................................................11

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MRI medical exam
Magnet removal is not required for magnetic field strengths at 1.5 Tesla. For magnetic field
strengths greater than 1.5 Tesla magnet removal is required for MRI compatibility. In order to
insure patient safety during an MRI exam and to
prevent damage to the Neuro Zti, the following instructions must be understood and followed.
Any questions or concerns should be clarified with the manufacturer prior to conducting an MRI
exam with a patient implanted with the Neuro Zti.
Warnings:
1. All external cochlear implant components such as the BTE, antenna, audio streamers, cables
and any other cochlear implant associated accessories are NOT compatible with MRI examina-
tion and must be removed prior to entering an MRI examination room.
There is a risk that prolonged exposure to high strength magnetic fields could demagnetize the
implanted magnet held by the Neuro Zti. To reduce the risk of demagnetization, care should be
taken to keep the longitudinal axis of the patient’s head parallel to the scanner’s principal
magnetic field. Loss of magnetization may interfere with antenna retention following an MRI
MRI Strength 1.5 Tesla 3 Tesla
Recommended intervention No surgery required, use standard
head bandage
Remove magnet prior to
MRI exam

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procedure. Should transcutaneous magnetic coupling become compromised, surgical interven-
tion may be required to replace the implanted magnet following the procedures described
below.
2. If the region of medical interest is likely to fall within the projected artifact produced by the
Neuro Zti, the magnet may be removed prior to an MRI exam for MRI strengths at 1.5 Tesla to
minimize artifacts.
3. It is possible that the medical region of interest may be obscured by artifacts produced by the
Neuro Zti even with the implanted magnet removed.
4. It is possible that the patient may experience auditory sensations such as crackling, beeping
and/or a humming sound during an MRI exam. The patient should be advised of this possi-
bility and that it does not indicate device malfunction or damage.
5. If the patient is a bilateral Neuro Zti recipient, the same procedures outlined in this document
must also be followed for the contralateral implant.
6. Head first: Technicians must slide the Neuro Zti recipient head first in the MRI machine
independent of the anatomical region to be scanned. Caution: Entering feet first is contra-
indicated.
7. Note: To perform an MRI exam, the radiologist should fill out an exam form that can be found
at www.oticonmedical.com. The form must be sent back for approval to the manufacturer that
is mentioned on the cover before performing the MRI exam.

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A. MRI exam with implanted magnet in place (at 1.5 Tesla) recommended guidelines for
radiologists.
1. The patient must have been implanted with a cochlear implant at least 6 months prior to
the MRI examination.
2. All external part or cochlear implant system accessories should be removed.
3. The patient must have a compression bandage applied to the head to secure the implant
position.
4. For all MRI examinations requiring the head of the patient to be placed in the center of the
tunnel, the position of the patient must be conformed to the ‘usual position’ (figure below).
It is imperative that this position applies at least 30 cm before the beginning of the tunnel.
Note: When carrying out an MRI exam with a Neuro Zti cochlear implant, do not use the Head
Coil Array.
‘Usual Position’ with nose up
BO

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B. MRI exam with magnet removal (3 Tesla)
Magnet removal or replacement is a surgical procedure and must take place following standard
surgical practice to insure sterility.
Required tools:
In order to extract the magnet of the Neuro Zti implant, the surgeon will need to have the three
elements mentioned below:
A Neuro Zti magnet extractor (M80177) that can be ordered directly from Oticon Medical or the
local Oticon Medical distributor. The tool is packed non-sterile. It must be sterilized following
Oticon Medical re-cleaning and sterilization protocol (M80330) before performing surgery.

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A Neuro Zti dummy magnet (M80178). The dummy magnet is packed
sterile. It shall be ordered directly from Oticon Medical or Oticon
Medical local distributor and before performing a magnet extraction.
The dummy magnet is an empty titanium casing that does not hold
any magnet in order to avoid any harm caused by strong electromag-
netic field. The dummy magnet must be put in place after extracting
the implant magnet in order to avoid the fibrosis to form into the
implant.
Note: The cochlear implant recipient should be informed the proces-
sor antenna can no longer be kept in place on the head if no external
magnet system or headband is used.
A Neuro Zti magnet (M80179) for replacement. The magnet is packed
sterile. It shall be ordered from Oticon Medical or Oticon Medical
local distributor before performing any medical exam that requires
a magnet extraction.
DUMMY

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Step 1: Make an incision and expose the magnet.
Make a small incision to access the magnet. Cut any fibrosis
tissue to expose the magnet. Decision on optimal incision size
and location should be done on a case by case basis, aiming
to minimize the probability of skin-flap complications.
In order to avoid potential damage to the electrode array, inci-
sions anterior to the receiver (over the toroid) are not recom-
mended. Incision should be made on the side of the implant
receiver.
Note: A proper connection between the extractor tool and the
magnet demands an angle of 90 degrees.
90°

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Step 2: Remove the magnet
When using the magnet extractor, place it facing the magnet to extract.
In order to use the magnet extractor tool, 90 degree access with respect to the primary plane of
the receiver is required (Figure 1).
To grab the magnet that is placed in the implant receiver, lock the extractor tool to the magnet by
turning ¼ to the left (minimum 20° counter-clockwise) while stabilizing the receiver with your fin-
ger (Figure 2). The magnet will be released from the implant.
Note: The magnet extractor tool is magnetic at the point of contact to further assist at extraction
(Figure 3).
Hold with fingers,
lock the extractor tool and pull
Figure 2Figure 1 Figure 3
90°

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Step 3: Replace magnet with dummy magnet
Remove the dummy from the sterile packaging (Figure 1). Using a finger, push the dummy at the
center of the implant receiver until it stops. (Figure 2).
Note: The dummy magnet is now in place and cannot be removed without the magnet extractor
tool.
Figure 1
Figure 2

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Step 4: Close incision according to best surgical practice
Note: Wait until incision is healed prior to wearing the external sound processor.
C. Dummy removal and magnet replacement intervention
Follow same procedures as in “B. MRI with magnet removal (3 Tesla)”.
D. Magnet replacement
To remove the magnet, follow procedure of “B. MRI Exam with magnet removal (3 Tesla)”.
Instead of replacing the magnet with a dummy magnet (M80178); place a new magnet
(M80179) instead.
This procedure would be indicated also if a patient’s magnet was demagnetised following
repeated MRI at 1.5T or an accidental MRI at 3T that demagnetised a magnet.
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M - version D
Oticon Medical
Neurelec S.A.S
2720 Chemin Saint Bernard
06220 Vallauris  France
TEL : [phone]
FAX : [phone]
[e-mail]
www.oticonmedical.com