Download Detailed guidelines for each individual device

Neurological Patient and Technical Services Department
November 2005 Page 1 of 27
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Compatibility Guidelines for Neurostimulation Products
Contents:
Device Compatibility
Bone Growth Stimulators: 2
Defibrillation/Cardioversion: 2
Dental Drills and Ultrasonic Probes: 2
Diathermy (Shortwave, Microwave, Therapeutic Ultrasound): 3
Effects on Other Implanted Devices: 4 Electrocautery: 4, 5
Electrolysis: 6
EMI/EMC: 6, 7
High-output Ultrasonics/Lithotripsy: 7
Home or Occupational Environment
(electromagnetic field devices): 7, 8
Household Items: 9, 10
Laser Procedures: 10
MRI: 10
Other Medical Procedures (CT Scan, Diagnostic Ultrasound,
Diagnostic Xray, MEG, PET): 11 Patient Activities
(Unexpected Changes in Stimulation,
Driving, Operating Power Tools): 11, 12
Psychotherapeutic Procedures: 12
Radiation Therapy: 12
RF or Microwave Ablation: 12
Scuba Diving or Hyperbaric Chambers: 13
Skydiving, Skiing, or Hiking in the Mountains: 13
TENS: 13
Theft Detectors: 13, 14
Therapeutic Magnets: 14, 15
Programmer/Programming Compatibility
Patient Control Devices May Affect Other Implanted Devices: 15
Patient Magnet/Control Magnet: 15
Programmer Interaction with Cochlear Implant: 15
Programmer Interaction with Other Implanted Devices/Inadvertent Programming: 15, 16
Telemetry Disruption from EMI: 16
Appendices
Table of Potential Effects of EMI from Devices or Procedures: 17
Appendix for MRI and Activa Therapy (Deep Brain Stimulation): 18-22
Appendix for MRI and neurostimulation therapy for chronic pain: 23-27
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Bone growth stimulators – Keep
external magnetic field bone growth
stimulator coils 45 cm (18 in.) away from
the neurostimulation system. When using
either an implantable or external bone
growth stimulator, ensure that both the
bone stimulator and neurostimulator are
working as intended.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Precautions Required
Bone Growth Stimulators – Keep
external magnetic field bone growth
stimulator coils 18 in (45 cm) away from
the neurostimulator / lead system. When
using either an implantable or external
bone growth stimulator, ensure that both
the bone stimulator and neurostimulator
are working as intended.
Defibrillation or cardioversion – When a
patient is in ventricular or atrial fibrillation,
the first consideration is patient survival.
External defibrillation or cardioversion can
damage a neurostimulation system and
cause induced currents in the leadextension portion of the neurostimulation
system that can injure the patient.
Minimize the current flowing through the
neurostimulator system by following these
guidelines:
•
Position defibrillation paddles as far
from the neurostimulator as possible.
•
Position defibrillation paddles
perpendicular to the neurostimulation
system.
•
Use the lowest clinically appropriate
energy output (watt seconds). After
defibrillation, confirm the neurostimulation
system is functioning as intended.
External Defibrillators – If a patient
requires external defibrillation, the first
consideration should be patient survival.
Safety for use of external defibrillatory
discharges on patients with
neurostimulation systems has not been
established. External defibrillation may
damage a neurostimulator. If external
defibrillation is necessary, follow these
precautions to minimize current flowing
through the neurostimulator and lead
system:
•
Position defibrillation paddles as far
from the neurostimulator as possible.
•
Position defibrillation paddles
perpendicular to the implanted
neurostimulator-lead system.
•
Use the lowest clinically appropriate
energy output (watt seconds).
•
Confirm neurostimulation system
function following any external
defibrillation.
External Defibrillators –Safety for use of
external defibrillatory discharges on
patients with neurostimulation systems has
not been established. External defibrillation
may damage or cause reprogramming of a
neurostimulator. If external defibrillation is
necessary, follow these precautions to
minimize current flowing through the
neurostimulator and lead system:
•
Position defibrillation paddles as far
from the neurostimulator as possible.
•
Position defibrillation paddles
perpendicular to the neurostimulatorlead system.
•
Use the lowest clinically appropriate
energy output (watt seconds).
•
Confirm the neurostimulation system
function following any external
defibrillation.
Defibrillation / Cardioversion – When a
patient is in ventricular or atrial fibrillation,
the first consideration should be patient
survival. External defibrillation or
cardioversion can damage a
neurostimulation system. It is
recommended not to use defibrillation or
card ioversion paddles near the
neurostimulator. When external
defibrillation or cardioversion is
necessary, minimize the current flowing
through the neurostimulator and lead
system as follows:
•
Position paddles as far from the
neurostimulator as possible.
•
Position paddles perpendicular to the
neurostimulation system.
•
Use the lowest clinically appropriate
energy output (watt seconds).
•
Neurostimulation system function
should be confirmed after external
defibrillation.
Defibrillation or cardioversion may also
cause induced currents in the lead portion
of the neurostimulation system that could
be hazardous or cause further injury.
Dental drills and ultrasonic
probes – Turn OFF the neurostimulator.
Keep the drill or probe 15 cm (6 in) away
from the neurostimulator.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Dental Drills and Ultrasonic Probes –
Turn OFF the neurostimulator. Keep the
drill or probe 6 in (15 cm) away from the
neurostimulator.
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Contraindication
Contraindication
Contraindication
Contraindication
Diathermy – Do not use shortwave
diathermy, microwave diathermy or
therapeutic ultrasound diathermy (all now
referred to as diathermy) on patients
implanted with a neurostimulation system.
Energy from diathermy can be transferred
through the implanted system and can
cause tissue damage at the location of the
implanted electrodes, resulting in severe
injury or death.
Diathermy can also damage the
neurostimulation system components,
resulting in loss of therapy and requiring
additional surgery for system explantation
and replacement. Advise your patient to
inform all their healthcare professionals
that they should not be exposed to
diathermy treatment.
Injury to the patient or damage to the
device can occur during diathermy
treatment when:
•
the neurostimulation system is turned
ON or OFF.
•
diathermy is used anywhere on the
body—not just at the location of the
neurostimulation system.
•
diathermy delivers heat or no heat.
any component of the neurostimulation
system (lead, extension, neurostimulator)
remains in the body.
Implantation of an Activa Brain
Stimulation System is contraindicated for:
•
Patients exposed to diathermy. Do not
use shortwave diathermy, microwave
diathermy or therapeutic ultrasound
diathermy (all now referred to as
diathermy) on patients implanted with
a neurostimulation system. Energy
from diathermy can be transferred
through the implanted system and can
cause tissue damage at the location of
the implanted electrodes, resulting in
severe injury or death.
Diathermy is further prohibited
because it can also damage the
neurostimulation system components
resulting in loss of therapy, requiring
additional surgery for system
explantation and replacement. Injury
or damage can occur during
diathermy treatment whether the
neurostimulation system is turned “on”
or “off.” Advise your patients to inform
all their healthcare professionals that
they should not be exposed to
diathermy treatment.
Diathermy –Do not use shortwave
diathermy, microwave diathermy or
therapeutic ultrasound diathermy (all now
referred to as diathermy) on patients
implanted with a neurostimulation system.
Energy from diathermy can be transferred
through the implanted system and can
cause tissue damage at the location of the
implanted electrodes, resulting in severe
injury or death.
Diathermy is further prohibited because it
can also damage the neurostimulation
system components resulting in loss of
therapy, requiring additional surgery for
system explantation and replacement.
Injury or damage can occur during
diathermy treatment whether the
neurostimulation system is turned “on” or
“off.” Advise your patients to inform all
their healthcare professionals that they
should not be exposed to diathermy
treatment.
Diathermy – Do not use shortwave
diathermy, microwave diathermy or
therapeutic ultrasound diathermy (all now
referred to as diathermy) on patients
implanted with a neurostimulation system.
Energy from diathermy can be transferred
through the implanted system and can
cause tissue damage at the location of
the implanted electrodes, resulting in
severe injury or death.
Diathermy is further prohibited because it
can also damage the neurostimulation
system components resulting in loss of
therapy, requiring additional surgery for
system explantation and replacement.
Injury or damage can occur during
diathermy treatment whether the
neurostimulation system is turned “on” or
“off.” Advise your patients to inform all
their healthcare professionals that they
should not be exposed to diathermy
treatment.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
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Neurostimulator interaction with
implanted cardiac devices – When a
patient’s medical condition requires both a
neurostimulator and an implanted cardiac
device (eg, pacemaker, defibrillator),
physicians involved with both devices (eg,
neurologist, neurosurgeon, cardiologist,
cardiac surgeon) should discuss the
possible interactions between the devices
before surgery. To minimize or prevent the
effects described below, implant the
devices on opposite sides of the body and
follow any additional instructions.
• Defibrillation therapy from an
implanted defibrillator may damage
the neurostimulator.
• The electrical pulses from the
neurostimulation system may interact
with the sensing operation from cardiac
devices and could result in an
inappropriate response of the cardiac
devices. To minimize or prevent the
cardiac device from sensing the
neurostimulator output, program the
neurostimulator to a bipolar
configuration and to a minimum rate of
60 Hertz. Program the cardiac device
to bipolar sensing.
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Effects on Other Medical
Devices – The Activa System may affect
the operation of other implanted devices,
such as cardiac pacemakers and
implantable defibrillators. Possible effects
include sensing problems and
inappropriate device responses. If the
patient requires concurrent implantable
pacemaker and/or defibrillator therapy,
careful programming of each system may
be necessary to optimize the patient’s
benefit from each device.
Cal Tech Services for further
information.
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Effects on Other Implanted Devices The
neurostimulation system may affect the
operation of other implanted devices, such
as cardiac pacemakers and implantable
cardioverter defibrillators. Physical
proximity may cause sensing problems
and inappropriate device responses. If the
patient requires concurrent implantable
pacemaker and/or defibrillator therapy,
evaluation of any potential interference
problems and careful programming of each
system may be necessary to optimize the
patient’s benefit from each device.
Interaction with other Implantable
Devices – When another implantable
device (e.g., pacemakers, defibrillators, or
cochlear implants) is required, the
physicians involved in both therapies
should discuss the possible interaction
between the devices. Electrical impulses
from the neurostimulation system may
affect the sensing operation and cause
inappropriate device response of other
implanted devices. Careful programming
of each system may optimize the benefit
from each device. Follow these suggested
guidelines:
• The neurostimulator should be
placed on the opposite side of the
body from the other implanted
device.
• The neurostimulator should be
reprogrammed to bipolar stimulation
•
Each system should be checked to
ensure that it is working as intended.
Cal Tech Services for further
information.
Cal Tech Services for further
information.
Cal Tech Services for further in
formation.
See also “Programmer interaction with
other active implanted devices”.
Electrocautery – If electrocautery is used
near an implantable device or contacts a
device or insertion-needle, the following
effects may occur:
• The tissue surrounding the insertionneedle (during placement of a
percutaneous lead) may be damaged.
Electrocautery – Electrocautery can
damage the lead, the extension, or both. It
can also cause temporary suppression of
neurostimulator output and/or
reprogramming of the neurostimulator. If
use of electrocautery is necessary, the
current path (ground plate) should be kept
as far away from the neurostimulator,
Electrocautery –Electrocautery can cause
temporary suppression of neurostimulator
output and/or reprogramming of the
neurostimulator. For more information,
refer to “Cautery Protection” and “Power
ON Reset” below. No electrosurgical tip
should ever be used in the vicinity of an
implanted system. If
Caution: Do not use an electrosurgical tip
in close proximity (closer than 2 inches) to
the neurostimulator or lead.
Electrocautery – Electrocautery can
damage the lead or neurostimulator. It
can also cause temporary suppression of
neurostimulator output and/or reprogram
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•
The insulation on the lead or
extension may be damaged, resulting
in component failure or induced
currents into the patient that may
damage tissue or stimulate or shock
the patient.
• The neurostimulator may be
damaged, output may be temporarily
suppressed or increased, or
stimulation may stop because
parameters were changed to poweron-reset settings (eg, output OFF,
amplitude 0.0V).
When electrocautery is necessary, follow
these precautions:
•
Before using electrocautery, turn
OFF the neurostimulator.
•
Disconnect any cable connecting the
lead or extension to a screener or
external neurostimulator.
•
Use only bipolar cautery.
•
If unipolar cautery is necessary:
•
use only a low-voltage mode.
•
use the lowest possible power
setting.
•
keep the current path (ground
plate) as far from the
neurostimulator, extension, and
lead as possible.
•
do not use full-length operating
room table grounding pads.
After using electrocautery, confirm that
the neurostimulator is functioning as
intended.
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extension, and lead as possible, and use
of bipolar electrocautery is recommended.
use of electrocautery is necessary:
•
Turn off the neurostimulator before
performing electrocautery.
•
Avoid using spray coagulation. If
spray coagulation is necessary, keep
the power setting at less than 50
watts.
•
Keep the current path (ground plate)
as far away from the neurostimulator
as possible.
•
Bipolar cautery is recommended.
Refer to SCS/PNS guidelines, except
for first bulet.
Cautery Protection
Cautery protection is incorporated into the
InterStim Model 3023 Neurostimulator. It
enables the neurostimulator to return to
normal function following electrosurgery.
It is recommended that the electrical
current path between the cautery tip
electrode and the indifferent electrode be
kept as far away from the
neurostimulator/lead system as possible.
The use of bipolar cautery is
recommended.
Caution: Do not use an electrosurgical tip
in close proximity (that is, closer than 2
inches) to the neurostimulator, extension
(if used), or lead.
Power ON Reset
As a safety feature, if the neurostimulator
is subjected to extreme electromagnetic
stress (such as from cautery or
defibrillation procedures), its parameters
will automatically reset to the original
shipping values except for amplitude
resolution set at fine.
Once the neurostimulator is removed from
the interference source, the device must
be reprogrammed to the desired settings.
In addition, the serial number is lost and
cannot be reprogrammed.
Refer to SCS/PNS guidelines.
the neurostimulator to Power ON Reset
parameters (output off, amplitude = 0V),
which requires neurostimulator
reprogramming. Electrocautery may also
cause induced currents in the lead portion
of the neurostimulation system that could
be hazardous or cause further injury.
Follow these precautions when using
electrocautery:
•
Turn off the neurostimulator before
performing electrocautery.
•
Only bipolar cautery is
recommended.
•
If unipolar cautery is necessary:
–
Do not use high voltage modes.
–
Keep the power setting as low
as
possible.
– Keep the current path (ground
plate) as far away from the
neurostimulator and lead as
possible.
•
Confirm the neurostimulator function
after electrocauterization.
Refer to SCS/PNS guidelines, except
for first bulet.
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Electrolysis – Turn OFF the
neurostimulator. Keep the electrolysis
wand at least 15 cm (6 in) away from the
neurostimulator.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Electrolysis – Turn OFF the
neurostimulator, and keep the electrolysis
wand at least 6 in (15 cm) away from the
neurostimulator.
Electromagnetic interference (EMI) –
Electromagnetic interference is a field of
energy generated by equipment found in
the home, work, medical or public
environments that is strong enough to
interfere with neurostimulator function.
Neurostimulators include features that
provide protection from electromagnetic
interference. Most electrical devices and
magnets encountered in a normal day are
unlikely to affect the operation of a
neurostimulator. However, sources of
strong electromagnetic interference can
result in the following:
• Serious patient injury or death,
resulting from heating of the implanted
components of the neurostimulation
system and damage to surrounding
tissue.
• System damage, resulting in a loss of
or change in symptom control and
requiring surgical replacement.
• Operational changes to the
neurostimulator, causing it to turn
ON or OFF (particularly in
neurostimulators enabled for magnet
use), or to reset to power-on-reset
(POR) settings, resulting in loss of
stimulation, return of symptoms, and
in the case of POR, requiring
reprogramming by a clinician.
• Unexpected changes in stimulation,
causing a momentary increase in
stimulation or intermittent stimulation,
which some patients have described
as a jolting or shocking sensation.
Although the unexpected change in
stimulation
Electromagnetic Interference (EMI)
Electromagnetic interference is a field
(electrical, magnetic or a combination of
both) that is generated by various medical
or environmental devices. These medical
and environmental (home, occupational,
and other) devices may generate enough
interference to change the parameters of a
neurostimulator; turn a neurostimulator off
and on, or cause a neurostimulator to
surge, shock, or jolt the patient.
In addition, it is possible for the extension,
lead, or both to “pick up” electromagnetic
interference and deliver an excess voltage,
which can in turn deliver an excessive
amount of heat to the brain. Refer to the
sections that follow for guidelines on the
interaction of electromagnetic interference
and an implanted Activa System.
Electromagnetic Interference – Patients
should exercise reasonable caution in
avoidance of devices which generate a
strong electric or magnetic field. Close
proximity to high levels of electromagnetic
interference (EMI) may cause a
neurostimulator to unexpectedly cease to
function or cause sensitive patients to
experience a momentary increase in their
perceived level of stimulation. Also, severe
EMI can permanently erase the
neurostimulator serial number, causing
“????” to be displayed in place of the serial
number.
Electromagnetic interference (EMI)
Electromagnetic interference is a field of
energy (electric, magnetic, or a
combination of both) generated by
equipment found in the home, work,
medical or public environments that is
strong enough to interfere with
neurostimulator function.
Neurostimulators include features that
provide protection from electromagnetic
interference. Most electrical devices and
magnets encountered in a normal day are
unlikely to affect the operation of a
neurostimulator. However, strong sources
of electromagnetic interference can result
in the following:
• Serious injury or death, resulting from
heating of the implanted
neurostimulation system components,
which can damage surrounding
tissue.
• System damage, requiring surgical
replacement or result in a loss of or
change in symptom control.
• Operational changes to the
neurostimulator, causing it to switch
ON or OFF (particularly in
neurostimulators enabled for magnet
use), or to reset to default factory
settings which may result in loss of
stimulation, return of symptoms, and
require reprogramming by the
physician.
Hospital or Medical Environment Kinetra
neurostimulators have been tested for
electromagnetic compatibility (EMC) in
electrical and magnetic fields that simulate
common sources of EMI found in a
hospital environment. Severe
electromagnetic fields, such as those that
exist near electrocautery equipment, can
reprogram a neurostimulator, temporarily
suppress the output of a neurostimulator,
and cause damage to the implanted
system components.
Telemetry usually continues to function
but may indicate that the neurostimulator
output is On when, in fact, no stimulation
is being delivered because the amplitude
is set to 0.0 V. Kinetra neurostimulators
have a protective circuit to prevent
Refer to SCS/PNS guidelines.
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feel uncomfortable, it does not
damage the device or injure the
patient directly. In rare cases, as a
result of the unexpected change in
stimulation, patients have fallen down
and been injured.
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damage to the circuitry, but a large burst
of electromagnetic energy may
temporarily affect the output and/or the
ability to reprogram the device. Severe
EMI (e.g., electrocautery, defibrillatory
discharge, MRI) can also erase the
neurostimulator serial number.
High-Output Ultrasonics –Use of highoutput ultrasonic devices, such as an
electrohydraulic lithotriptor, is not
recommended for patients with an
implanted neurostimulation system. While
there is no danger to the patient,
exposure to high-output ultrasonic
frequencies may result in damage to the
neurostimulator circuitry. If lithotripsy must
be used, do not focus the beam near the
neurostimulator.
High-output ultrasonics or lithotripsy –
Use of high-output ultrasonic devices,
such as electrohydraulic lithotriptors, is
not recommended for patients who have
an implanted neurostimulation system. If
lithotripsy must be used, do not focus the
beam within 15 cm (6 in) of the
neurostimulator.
Lithotripsy – Use of high output
ultrasonic devices, such as an
electrohydraulic lithotriptor, is not
recommended for patients with an
implanted neurostimulation system. While
there is no danger to the patient,
exposure to high output ultrasonic
frequencies may result in damage to the
neurostimulator circuitry. If lithotripsy must
be used, do not focus the beam near the
neurostimulator.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Electromagnetic field devices –
Patients should exercise care or avoid the
following equipment or environments:
•
Antenna of citizens band (CB) radio
or ham radio
•
Electric arc welding equipment
•
Electric induction heaters used in
industry to bend plastic
•
Electric steel furnaces
•
High-power amateur transmitters
•
High-voltage areas (safe if outside
the fenced area)
•
Linear power amplifiers
•
Magnetic degaussing equipment
•
Magnets or other equipment that
generates strong magnetic fields
•
Microwave communication
transmitters (safe if outside the
fenced area)
•
Perfusion systems
•
Resistance welders
Occupational Environments –
Commercial electrical equipment (arc
welders, induction furnaces, resistance
welders), communication equipment
(microwave transmitters, linear power
amplifiers, high-power amateur
transmitters), and high voltage power
lines may generate enough
electromagnetic interference (EMI) to
interfere with neurostimulator operation if
approached too closely.
Occupational Environments –
Commercial electrical equipment (arc
welders, induction furnaces, resistance
welders), communication equipment
(microwave transmitters, linear power
amplifiers, high-power amateur
transmitters), and high-voltage power
lines may generate enough EMI to
interfere with neurostimulator operation if
approached too closely.
Home or Job Environment
Kinetra neurostimulators should not be
affected by normal operation of electrical
equipment such as household appliances,
electric machine shop tools, microwave
ovens, RF transmitting systems, or
microwave frequency transmitting
systems. A strong magnetic field
(electromagnet or permanent magnet)
can switch the neurostimulator output
Refer to SCS/PNS guidelines.
High-Output Ultrasonics / Lithotripsy –
Use of high-output ultrasonic devices,
such as electrohydraulic lithotriptor, is not
recommended for patients with an
implanted neurostimulation system. If
lithotripsy must be used, do not focus the
beam within 6 inches (15 cm) of the
neurostimulator.
Home, Public, and Occupational
Environment
Exercise care or avoid the following
equipment or environments:
•
Antenna of citizen band (CB) radio or
ham radio
•
Electric arc welding equipment
•
Resistance welders
•
Electric induction heaters used in
industry to bend plastic
•
Electric steel furnaces
•
High voltage (safe if outside the
fenced area)
•
Television and radio transmitting
towers (safe if outside the fenced
area)
•
Microwave communication
transmitters (safe if outside the
fenced area)
•
Linear power amplifiers
•
High power amateur transmitters
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•
Television and radio transmitting
towers (safe if outside the fenced
area)
If patients suspect that equipment is
interfering with neurostimulator function,
they should do the following:
•
Move away from the equipment or
object.
•
If possible, turn OFF the equipment
or object.
•
Then, if necessary, use the control
magnet or patient programmer to
return the neurostimulator to the
desired ON or OFF state.
•
Inform the equipment owner or
operator of the occurrence.
If the above actions do not resolve the
effects of the interference, or the patients
suspect that their therapy is not effective
after exposure to EMI, they should
contact their physician.
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from On to Off or Off to On , but does not
change the programmed parameters. In
addition, theft detectors and airport/security
screening devices can affect the
neurostimulator output and patient
stimulation.
Advise your patients to use care when
approaching theft detectors or
airport/security screening devices. If they
feel unwanted stimulation as they approach
the device, suggest that they request
assistance to bypass the device. Advise
your patients to avoid or to exercise care
when approaching the following:
•
Theft detectors
•
Airport/security screening devices
•
Large stereo speakers with magnets
•
Electric arc welding equipment
•
Electric steel furnaces
•
Electric induction heaters (used in
industry to bend plastic)
•
Power lines
•
Electric substations and power
generators
If your patient suspects an electrical device
or magnet is interfering with the
neurostimulator, advise him/her to move
away from it, or turn the device off. Then,
the patient can use the control magnet or
therapy controller to set the neurostimulator
back to the desired On or Off state. When
switched On, the neurostimulator will
resume stimulation at the previously
programmed level.
1
Unexpected On/Off switching of the
Kinetra Model 7428 Neurostimulator may
be avoided by disabling the magnet control
circuit with the clinician programmer
software. If the magnet control circuit is
disabled, patients will require a Model 7436
Therapy Controller to turn their therapy On
or Off.
1
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•
•
•
Perfusion systems
Magnets or other equipment that
generates strong magnetic fields
Magnetic degaussers
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Household items – Most household
appliances and equipment that are
working properly and grounded properly
will not interfere with the neurostimulation
system. The following equipment is
generally safe if patients follow these
guidelines:
• Freezer, refrigerator, or storm door
magnets that hold the door closed:
Do not lean against the magnetic strip
of the door.
• Radio-frequency sources (AM/FM
radios, analog and digital cellular
telephones, cordless and
conventional telephones): Keep
these items at least 10 cm (4 in)
away from the implanted
neurostimulator.
• Stereo speakers and radios for the
home or car: Do not lift or carry
speakers or radios near the
neurostimulator.
• Sewing machines or salon hair
dryer: Keep the neurostimulator
away from the motors.
• Computer disk drives: Keep the
neurostimulator away from the disk
drives.
• Induction range: Keep the
neurostimulator away from the
burners while the burners are turned
ON.
• Power tools: Keep the motor away
from the neurostimulator, lead, and
extension.
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Home Appliances – Home appliances
that are in good working order and
properly grounded do not usually produce
enough electromagnetic interference (EM
I) to interfere with neurostimulator
operation. However, items with magnets
(e.g., stereo speakers, refrigerators,
freezers, power tools) may cause the
neurostimulator to switch On or Off.
Home Appliances –Home appliances
that are in good working order and
properly grounded do not usually produce
enough electromagnetic interference (EM
I) to interfere with neurostimulator
operation.
Home, Public, and Occupational
Environment
Most household appliances and
equipment that are in good working order
and properly grounded will not interfere
with the
neurostimulation system.
If patients suspect that equipment is
interfering with neurostimulator
function, they should do the following:
1. Move away from the equipment or
object.
2. If possible, turn off the equipment or
object.
3. Inform the equipment owner / operator
of the occurrence.
If the above actions do not resolve the
effects of the interference, or the patients
suspect that their therapy is not effective
after exposure to EMI, they should
contact their physician.
Radio Frequency Sources – Analog and
digital cellular phones, AM/FM radios,
cordless phones, and conventional wired
telephones may contain permanent
magnets. To prevent undesired turning
On or Off of the stimulation, these devices
should be kept at least 4 inches away
from the implanted neurostimulator.
Refer to SCS/PNS guidelines.
Physician Instructions to the Patient
Advise patients to exercise care when
approaching the following:
•
Large stereo speakers (which contain
magnets)
•
Electric arc welding equipment
•
Electric steel furnaces
•
Electric induction heaters used in
industry to bend plastic
•
Power lines
•
Electric substations and power
generators
If a patient suspects an electrical device
or magnet is interfering with his or her
neurostimulator, the patient should move
away from or turn the interfering device
off. If necessary, the patient can use his
or her control magnet or patient
programmer to set the neurostimulator
back to the desired on or off state. (When
switched on, the neurostimulator will
resume stimulation at the previously
programmed level.)
Refer to SCS/PNS guidelines.
Generally Safe if precautions are
followed:
• Freezer, refrigerator, or storm door
magnets that hold the door closed:
Do not lean against the magnetic strip
of the door.
• Radio Frequency Sources: Analog
and digital cellular phones, AM/FM
radios, cordless phones, and
conventional wired telephones, etc.,
should be kept at least 4 in (10 cm)
away from the implanted
neurostimulator.
• Stereo speakers and radios for the
home or car: Do not lift or carry them
so that they are close to or touching
the part of your body where the
neurostimulator is located.
• Sewing machines or salon hair
dryer: Keep the neurostimulator
away from the motors.
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•
•
•
Laser procedures – Turn OFF the
neurostimulator. Keep the laser directed
away from the neurostimulation system.
Magnetic Resonance Imaging
MRI RF transmit body coil – Medtronic
recommends that you do not conduct an
MRI examination using an RF transmit
body coil on a patient with any implanted
neurostimulation system component
because the interaction of the MRI with
the neurostimulation system may lead to
serious injury or death. See the section
“Risks associated with MRI examination”
on page 24.
MRI transmit/receive head coil – An
MRI examination of the head only (no
other part of the body) can be conducted
safely using an RF transmit/receive head
coil when all instructions in “Appendix B:
MRI and neurostimulation therapy for
chronic pain” on pages 23-27 are
followed.
REFER TO MRI APPENDIX FOR SCS/PNS
ON PAGE 23.
Refer to SCS/PNS guidelines.
Contraindication
Patients who will be exposed to Magnetic
Resonance Imaging (MRI) using a full
body transmit radio-frequency (RF) coil, a
receive-only head coil, or a head transmit
coil that extends over the chest area.
Performing MRI with this equipment can
cause tissue lesions from component
heating, especially at the lead electrodes,
resulting in serious and permanent injury
including coma, paralysis or death.
Warnings
Magnetic Resonance Imaging – Do not
conduct an MRI examination on a patient
with any implanted Activa System
component until you read and fully
understand all MRI information in the
Kinetra or Soletra Manual. Do not conduct
an MRI examination at parameters other
than those described in this guideline.
Failure to follow all warnings and
guidelines related to MRI can result in
serious and permanent injury including
coma, paralysis, or death.
REFER TO MRI APPENDIX FOR KINETRA
ON PAGE 18.
Computer disk drives: If repairing or
adding additional components to a
computer, keep the neurostimulator
away from the disk drives.
Induction range: Keep the
neurostimulator away from the burners
while the burners are turned on.
Power tools: Keep the motor away
from the neurostimulator and lead.
Refer to SCS/PNS guidelines.
Laser Procedures – Turn off the
neurostimulator, and keep the laser
directed away from the neurostimulation
system.
Magnetic-Resonance Imaging –
Patients with an implanted device should
not be exposed to the electromagnetic
fields produced by magnetic resonance
imaging (MRI). Use of MRI may
potentially result in system failure or
dislodgement, heating, or induced
voltages in the neurostimulator and/or
lead. An induced voltage through the
neurostimulator or lead may cause
uncomfortable, “jolting,” or “shocking”
levels of stimulation.
Clinicians should carefully weigh the
decision to use MRI in patients with an
implanted neurostimulation system, and
note the following:
• Magnetic and radio-frequency (RF)
fields produced by MRI may change
the neurostimulator settings, activate
the device, and injure the patient.
• Patients treated with MRI should be
closely monitored and programmed
parameters verified upon cessation of
MRI.
Magnetic Resonance Imaging (MRI) –
Patients with an implanted device should
not be exposed to the electromagnetic
fields produced by magnetic resonance
imaging (MRI). Use of MRI may
potentially result in system failure,
dislodgement, heating, or induced
voltages in the neurostimulator and/or
lead. An induced voltage through the
neurostimulator or lead may cause
uncomfortable, “jolting,” or “shocking”
levels of stimulation. Clinicians should
carefully weigh the decision to use MRI in
patients with an implanted
neurostimulation system, and note the
following:
• Magnetic and radio-frequency (RF)
fields produced by MRI may change
the neurostimulator settings and
injure the patient.
• Patients treated with MRI should be
closely monitored and programmed
parameters verified upon cessation of
MRI.
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Other medical procedures – EMI from
the following medical procedures is
unlikely to affect the neurostimulation
system:
•
Computerized Axial Tomography (CT
or CAT) scans
•
Diagnostic ultrasound (eg, carotid
scan, doppler studies)
Note: To minimize potential image
distortion, turn OFF the
neurostimulator and keep the
transducer 15 cm (6 in) away from
the neurostimulation system.
•
Diagnostic x-rays or fluoroscopy
Notes:
ņ To minimize potential image
distortion, turn OFF the
neurostimulator.
ņ Tight pressure such as used during
mammography may damage the
neurostimulator or disconnect the
neurostimulation system
components, which may require
surgery to reconnect or replace
components. During x-ray
procedures that require external
compression around implanted
components, the x-ray equipment
should be adjusted to limit the
amount of pressure exerted on the
neurostimulator.
•
Magnetoencephalography (MEG)
•
Positron Emission Tomography
(PET) scans
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Medical Environment
Most routine diagnostic procedures, such
as fluoroscopy and x-rays, are not
expected to affect system operation.
However, because of higher energy
levels, sources such as transmitting
antennas found on various diagnostic and
therapeutic equipment may interfere with
the Activa System.
Refer to SCS/PNS guidelines.
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Medical Environment
Effects in Monitoring Devices
When using diagnostic monitoring devices
such as an electrocardiogram (ECG),
Holter Monitor, electroencephalogram
(EEG), or implantable heart monitor,
pulses from the neurostimulation system
may be detected as an electrical signal.
When evaluating the diagnostic
information, be sure to identify the
neurostimulator pulses as intrinsic.
Effects from Diagnostic Procedures
Most routine diagnostic procedures, such
as fluoroscopy and x-rays, are not
expected to affect neurostimulation
system operation. However, because of
higher energy levels, sources such as
transmitting antennas may interfere with
the system.
Effects from Diagnostic Procedures
Ultrasound Scanning –Ultrasonic
scanning equipment may cause
mechanical damage to an implanted
neurostimulator or implanted lead if used
directly over the neurostimulator or lead
implant site.
Refer to SCS/PNS guidelines.
Diagnostic Ultrasound (e.g., carotid
scan, doppler studies) –
An implanted neurostimulation system is
unlikely to interfere with diagnostic
ultrasound. To minimize potential image
distortion, turn OFF the neurostimulator
and keep the transducer 15 cm (6 in)
away from the neurostimulation system.
Medical and Hospital Environment
Safe from Electromagnetic Interference
The following medical procedures are not
likely to affect the implanted system:
•
Computerized Axial Tomography (CT
or CAT) Scans
•
Diagnostic X-rays / Fluoroscopy
Note: Tight pressure can affect the
system. Refer to “X-rays Requiring
Tight Enclosure” on page 46.
•
Magnetoencephalography (MEG)
•
Positron Emission Tomography
(PET) Scans
X-rays Requiring Tight Enclosure –
Pressing the neurostimulator too tightly
during X-ray procedures that require
enclosure of the implant area may
damage the neurostimulator or disconnect
the neurostimulation system components,
which may require surgery to fix the
system or replace components. Adjust the
X-ray equipment to limit the amount of
pressure exerted on the neurostimulator
during procedures that require enclosure
of the implant area.
Refer to SCS/PNS guidelines.
Patient activities
Unexpected changes in stimulation –
Electromagnetic interference, postural
changes, and other activities may cause a
perceived increase in stimulation, which
some patients have described as
Patient Activities/Environmental
Precautions – Patients should exercise
reasonable caution in avoidance of
devices which generate a strong electric or
magnetic field. Close proximity to high
levels of electromagnetic interference
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
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uncomfortable stimulation (jolting or
shocking sensation); therefore, patients
should reduce the amplitude to the lowest
setting and turn OFF the neurostimulator
before engaging in activities that could be
unsafe for themselves or others if they
received an unexpected jolt or shock (eg,
driving, operating power tools). Patients
should discuss these activities with their
physician.
(EM I) may cause a neurostimulator to
switch On or Off. The system also may
unexpectedly cease to function due to
battery depletion or other causes. For
these reasons, the patient should be
advised about any activities that would be
potentially unsafe if their symptoms
unexpectedly return. For additional
information about devices which generate
electromagnetic interference, call
Medtronic at 1-800-328-0810.
Psychotherapeutic procedures – Safety
has not been established for
psychotherapeutic procedures using
equipment that generates electromagnetic
interference (eg, electroconvulsive
therapy, transcranial magnetic
stimulation) in patients who have an
implanted neurostimulation system.
Induced electrical currents may cause
heating, especially at the lead electrode
site, resulting in tissue damage.
Psychotherapeutic Procedures – The
safety of psychotherapeutic procedures
using equipment that generates
electromagnetic interference (e.g.,
electroshock therapy, transcranial
magnetic stimulation) has not been
established.
Radiation therapy – Do not direct high
radiation sources such as cobalt 60 or
gamma radiation at the neurostimulation
system. If radiation therapy is required
near the neurostimulation system, place
lead shielding over the device to help
prevent radiation damage.
High Radiation Sources – High radiation
sources, such as cobalt 60 or gamma
radiation, should not be directed at the
neurostimulator. If a patient requires
radiation therapy in the vicinity of the
neurostimulator, place lead shielding over
the device to prevent radiation damage.
High Radiation Sources –High-radiation
sources, such as cobalt 60 or gamma
radiation, should not be directed at the
neurostimulator. If a patient requires
radiation therapy in the vicinity of the
neurostimulator, place lead shielding over
the device to prevent radiation damage.
Radiation Therapy – Do not direct high
radiation sources such as cobalt 60 or
gamma radiation at the neurostimulation
system. If radiation therapy is required in
the vicinity of the neurostimulation
system, place lead shielding over the
device to prevent radiation damage.
Radio-frequency (RF) or microwave
ablation – Safety has not been
established for RF or microwave ablation
in patients who have an implanted
neurostimulation system. Induced
electrical currents may cause heating,
especially at the lead electrode site,
resulting in tissue damage.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Radiofrequency (RF) / Microwave
Ablation – Safety has not been
established for radiofrequency (RF) or
microwave ablation in patients with an
implanted neurostimulation system.
Induced electrical currents from these
procedures to the neurostimulation
system may cause heating, especially at
the lead electrode site, resulting in tissue
damage.
Refer to SCS/PNS guidelines.
Psychotherapeutic Procedures – The
safety of psychotherapeutic procedures
using equipment that generates
electromagnetic interference (e.g.,
electroshock therapy, transcranial
magnetic stimulation) has not been
established in patients with an implanted
neurostimulation system.
Refer to SCS/PNS guidelines.
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Scuba diving or hyperbaric chambers
– Patients should not dive below 10
meters (33 feet) of water or enter
hyperbaric chambers above 2.0
atmospheres absolute (ATA). Pressures
below 10 meters (33 feet) of water (or
above 2.0 ATA) could damage the
neurostimulation system. Before diving or
using a hyperbaric chamber, patients
should discuss the effects of high
pressure with their physician.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Skydiving, skiing, or hiking in the
mountains – High altitudes should not
affect the neurostimulator; however, the
patient should consider the movements
involved in any planned activity and take
precaution to avoid putting undue stress
on the implanted system.
Patients should be aware that during
skydiving, the sudden jerking that occurs
when the parachute opens may cause
lead dislodgment or fractures, which may
require surgery to repair or replace the
lead.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Transcutaneous electrical nerve
stimulation (TENS) – Do not place TENS
electrodes so that the TENS current
passes over any part of the
neurostimulation system. If patients feel
that the TENS may be interfering with the
implanted neurostimulator, patients
should discontinue using the TENS until
they talk with their doctor.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
TENS (Transcutaneous External
Neurostimulator) – Do not place TENS
electrodes so that the TENS current
passes over any part of the
neurostimulator / lead system. If the
patient feels that the TENS unit may be
interfering with the implantable
neurostimulator, the patient should talk
with their doctor.
Theft detectors and security screening
devices – Advise patients to use care
when approaching theft detector and
security screening devices (such as those
found in airports, libraries, and some
department stores). When approaching
Theft Detectors and Screening Devices
Patients should be advised to use care
when approaching security arches or
gates (such as those found in airports,
libraries, and some department stores)
because these devices can turn on or turn
Theft Detectors and Security
Screening Devices –
Patient should be advised to use care
when approaching theft detector and
security screening devices (such as those
found in airports, libraries, and some
Theft Detectors and Security
Screening Devices
Patients should be advised to use care
when approaching theft detector and
security screening devices (such as those
found in airports, libraries, and some
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these devices, patients should do the
following:
1. If possible, request to bypass these
devices. Patients should show the
security personnel their patient
identification card for the neurostimulator
and request a manual search. Security
personnel may use a handheld security
wand but patients should ask the security
personnel not to hold the security wand
near the neurostimulator any longer than
is absolutely necessary. Patients may
wish to ask for another form of personal
search.
2. If patients must pass through the theft
detector or security screening device,
they should turn OFF their
neurostimulator, approach the center of
the device and walk through normally.
a. If two security gates are present, they
should walk through the middle, keeping
as far from each gate as possible.
b. If one gate is present, they should walk
as far from it as possible.
Note: Some theft detectors may not be
visible.
3. Proceed through the security device.
Patients should not linger near or lean on
the screening device.
4. After patients pass through the security
device, they should turn ON their
neurostimulator.
Therapeutic magnets (eg, magnetic
mattresses, blankets, wrist wraps,
elbow wraps) – Keep the magnet at least
25 cm (10 in) away from the
neurostimulator. Magnetic fields of 10
gauss or less will generally not affect the
neurostimulator.
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off their neurostimulator. If an airport
security wand is used, they should ask
the security personnel to avoid placing the
wand over the neurostimulator.
When approaching these devices,
patients should do the following:
1. If security personnel are present, show
them the neurostimulator identification
card and request a hand search.
2. If patients must pass through the
security device, they should approach the
center of the device and walk normally.
a. If two security gates are present, they
should walk through the middle, keeping
as far away as possible from each gate.
b. If one gate is present, they should walk
as far away as possible from it.
Note: Some theft detectors may not be
visible.
3. Proceed through the security arch or
gate. Do not touch, lean on or linger near
the security arch or gate.
4. If patients suspect that their
neurostimulator was turned off, they
should make sure someone is able to turn
on the system again. (This person could
be the patient, if his or her medical
condition allows it. It could also be a
family member or clinician who has been
taught how to use the system.)
department stores). When approaching
these devices, patients should do the
following:
1. If possible, request to bypass these
devices. The patient should show security
personnel their patient identification card
for the neurostimulator and request a
manual search. Security personnel may
use a handheld security wand but the
patient should ask the security personnel
not to hold the security wand near the
neurostimulator any longer than is
absolutely necessary. The patient may
wish to ask for another form of personal
search.
2. If patients must pass through the theft
detector or security screening device,
they should turn their neurostimulator off,
approach the center of the device and
walk through normally.
a. If two security gates are present, they
should walk through the middle, keeping
as far away as possible from each gate.
b. If one gate is present, they should walk
as far away as possible from it.
Note: Some theft detectors may not be
visible.
3. Proceed through the security device.
Do not linger near or lean on the
screening device.
4. After patients pass through the security
device, they should turn their
neurostimulator on again.
DBS
Refer to SCS/PNS guidelines.
Therapeutic Magnets – Therapeutic
magnets (for example, those found in
bracelets, back braces, shoe inserts and
mattress pads) can cause inadvertent on
or off activations of the neurostimulator.
Therefore, patients should be advised not
to use them.
Refer to SCS/PNS guidelines.
department stores). When approaching
these devices, patients should do the
following:
1. If possible, request to bypass these
devices. The patient should show the
security personnel their patient
identification card for the neurostimulator
and request a manual search. Security
personnel may use a handheld security
wand but the patient should ask the
security personnel not to hold the security
wand near the neurostimulator any longer
than is absolutely necessary. The patient
may wish to ask for another form of
personal search.
2. If patients must pass through the theft
detector or security screening device,
they should approach the center of the
device and walk through normally.
a. If two security gates are present, they
should walk through the middle, keeping
as far away as possible from each gate.
b. If one gate is present, they should walk
as far away as possible from it.
Note: Some theft detectors may not be
visible.
3. Proceed through the security device.
Do not linger near or lean on the
screening device.
Therapeutic Magnets – If a
neurostimulator is enabled for magnet use,
therapeutic magnets (e.g., magnetic
mattresses, blankets, wrist wraps, elbow
wraps, etc.), can inadvertently turn the
neurostimulator ON or OFF. Advise
patients to keep their therapeutic magnets
at least 10 in (25 cm) away from their
neurostimulator. Magnetic fields of 10
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Patient control devices may affect
other implanted devices – Radio signals
(telemetry) from the patient programmer
may interfere with the performance of
other implantable devices.
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gauss or less will generally not affect the
neurostimulator.
Patient control devices may affect
other implanted devices – Do not place
the patient control device (ie, patient
programmer, control magnet, radiofrequency transmitter) over another active
implanted medical device (eg,
pacemaker, defibrillator, another
neurostimulator). The patient control
devices could unintentionally change the
operation of the other device.
Refer to SCS/PNS guidelines.
Patient magnet may damage items –
Do not place the patient magnet on or
near computer monitors, magnetic
storage disks or tapes, televisions, credit
cards, or other items affected by strong
magnetic fields. If the patient magnet is
too close, these items may be damaged.
Patient Magnet – The magnet provided
to the patient for device activation and
deactivation may damage televisions,
computer disks, computer monitors, credit
cards, and other items affected by strong
magnetic fields.
Control Magnet –The magnet provided
to the patient for device activation and
deactivation may damage televisions,
computer disks, credit cards, and other
items affected by strong magnetic fields.
N/A
Programmer interaction with a
cochlear implant – When the patient has
a cochlear implant, minimize or eliminate
the potential for unintended audible clicks
during telemetry by keeping the external
portion of the cochlear system as far from
the programming head as possible or by
turning OFF the cochlear implant during
programming.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Programmer interaction with other
active implanted devices – When a
patient has a neurostimulator and another
active implanted device (eg, pacemaker,
defibrillator, neurostimulator):
•
the radio-frequency (RF) signal used
to program these devices may reset
or reprogram the other device.
Inadvertent Programming – If more than
one neurostimulator is implanted, then the
potential for unintentional programming
changes to the other neurostimulator
exists. If two neurostimulators are
implanted, they must be implanted at
least 8 inches apart to minimize
interference. Verify final programmed
Refer to SCS/PNS guidelines.
Inadvertent Programming – To prevent
inadvertent programming or interference
with other implanted devices, follow these
guidelines:
•
If more than one neurostimulator is
implanted, then the potential for
unintentional programming changes
to the other neurostimulator exists. If
Refer to SCS/PNS guidelines.
Patient control devices may affect
other implanted devices – Do not place
the patient control device (ie, patient
programmer, control magnet, radiofrequency transmitter) over another active
implanted medical device (eg,
pacemaker, defibrillator, another
neurostimulator). The patient control
devices could unintentionally change the
operation of the other device.
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• the
magnet in a cardiac programmer
parameters by reviewing both devices at
may activate magnetically controlled
the conclusion of any programming
functions of the neurostimulator.
session.
To verify that inadvertent programming
did not occur, clinicians familiar with each Refer to SCS/PNS guidelines.
device should check the programmed
parameters of each device before the
patient is discharged from the hospital and
after each programming session of either
device (or as soon as possible after these
times).
Also, inform patients to contact their
physician immediately if they experience
symptoms that could be related to either
device or to the medical condition treated
by either device.
Telemetry signal disruption from EMI – Refer to SCS/PNS guidelines.
Do not attempt telemetry near equipment
that may generate electromagnetic
interference (EMI). If EMI disrupts
programming, move the programmer away
from the likely source of EMI. Examples of
sources of EMI are magnetic resonance
imaging (MRI), lithotripsy, computer
monitors, cellular telephones, x - ray
equipment, and other monitoring
equipment.
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two neurostimulators are implanted,
they must be implanted at least 20
cm (8 in) apart to minimize
interference. Verify final programmed
parameters by reviewing both
devices at the conclusion of any
programming session.
Refer to SCS/PNS guidelines.
Refer to SCS/PNS guidelines.
Neurological Patient and Technical Services Department
Device or procedure
November 2005 Page 17 of 27
Table 1. Potential Effects of EMI from Devices or Procedures
Device
Serious
Momentary
damage
patient
increase in
injury
stimulation
Bone growth stimulators
Defibrillation/cardioversion
3
Dental drills and ultrasonic probes
Diathermy, therapeutic
3
Electrocautery
3
Electrolysis
3
3
3
3
Laser procedures
31
3
3
3
3
3
3
3
Radiation therapy
Radio-frequency (RF)/microwave ablation
Theft detector
Transcutaneous electrical nerve stimulation (TENS)
1. DBS Therapy only.
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Therapeutic magnets
Therapeutic ultrasound
Intermittent
Stimulation
3
Household items
Magnetic Resonance Imaging (MRI)
Psychotherapeutic procedures (TMS, ECT)
3
3
3
3
Electromagnetic field devices: (eg, arc welding, power stations)
High-output ultrasonics/lithotripsy
Device turns
OFF/ON
3
3
3
3
3
3
Neurological Patient and Technical Services Department
November 2005 Page 18 of 27
FROM KINETRA DEEP BRAIN STIMULATION APPENDIX, MAGNETIC RESONANCE IMAGING
The Effects of Magnetic Resonance Imaging (MRI) on Deep Brain Stimulation
System (Activa) for Movement Disorders
Models:
Kinetra®: 7428
SoletraTM: 7426
Itrel® II: 7424
MRI and Activa Therapy
Introduction
It is important to read this section in its entirety before conducting an MRI examination on a patient with any implanted Activa System component. Contact
Medtronic Technical Services at 1-800-328-0810 if you have any questions.
Due to the number and variability of parameters that affect MRI compatibility, the safety of patients or continued functioning of Activa Systems exposed to MRI
cannot be absolutely ensured. MRI systems generate powerful electromagnetic fields that can produce a number of interactions with implanted components of the
Activa neurostimulation system. Some of these interactions, especially heating, are potentially hazardous and can lead to serious injury or death. However, with
appropriate control measures, particularly with respect to the selection of MRI parameters and RF coils, it is generally possible to safely perform an MRI head scan on
an Activa patient. In addition, Activa System components can affect the MRI image, potentially impacting the diagnostic use of this modality. The following
information describes the potential interactions and control measures that should be taken to minimize the risks from these interactions.
Contraindication: Implantation of an Activa Brain Stimulation System is contraindicated for patients who will be exposed to Magnetic Resonance Imaging
(MRI) using a full body transmit radio-frequency (RF) coil, a receive only head coil, or a head transmit coil that extends over the chest area. Performing
MRI with this equipment can cause tissue lesions from component heating, especially at the lead electrodes, resulting in serious and permanent injury
including coma, paralysis, or death.
Warnings:
• Do not conduct an MRI examination on a patient with any implanted Activa System component until you read and fully understand all the
information in this section. Failure to follow all warnings and guidelines related to MRI can result in serious and permanent injury including coma,
paralysis, or death.
• In-vitro testing has shown that exposure of the Activa neurostimulator system to MRI at parameters other than those described in this guideline
can induce significant heating at the lead electrodes or at breaks in the lead. Excessive heating may occur even if the lead and/or extension are the
only part of the Activa System that is implanted. Excessive heating can result in serious and permanent injury including coma, paralysis, or
death.
• MRI examinations of patients with an implanted Activa System should only be done if absolutely needed and then only if these guidelines are
followed. MRI should not be considered for Activa patients if other potentially safer diagnostic methods such as CT, X-ray, ultrasound, or other
methods will provide adequate diagnostic information.
• A responsible individual with expert knowledge about MRI, such as an MRI radiologist or MRI physicist, must assure all procedures in this
guidelines are followed and that the MRI scan parameters, especially RF specific absorption rate (SAR) and gradient dB/dt parameters, comply
Neurological Patient and Technical Services Department
•
November 2005 Page 19 of 27
with the recommended settings, both for the pre-scan (tuning) and during the actual MRI examination. The responsible individual must verify that
parameters entered into the MRI system meet the guidelines in this section.
Do not conduct an MRI examination if the patient has any other implants or limiting factors that would prohibit or contraindicate an MRI
examination.
Cautions:
• The neurostimulator, especially those without filtered feedthroughs such as the Itrel II Model 7424, may be reset or potentially damaged when
subjected to an MRI examination. If reset, the neurostimulator must be reprogrammed. If damaged, the neurostimulator must be replaced.
• MRI images may be severely distorted or image target areas can be completely blocked from view near the implanted Activa System components,
especially near the neurostimulator. If the MRI targeted image area is near the neurostimulator, it may be necessary to move the neurostimulator to
obtain an image, or use alternate imaging techniques. Do not remove the neurostimulator and leave the lead system implanted as this can result in
higher than expected lead heating.
• Carefully weigh any decision to perform magnetic resonance imaging (MRI) examinations on patients who require the neurostimulator to control
tremor. Image quality during MRI examinations may be reduced, because the tremor may return when the neurostimulator is turned off.
• If possible, do not sedate the patient so that the patient can provide feedback of any problems during the examination.
• Monitor the patient during the MRI examination. Verify that the patient is feeling normal and is responsive between each individual scan sequence
of the MRI examination. Discontinue the MRI immediately if the patient becomes unresponsive to questions or experiences any heating, pain,
shocking sensations/uncomfortable stimulation, or unusual sensations.
Note: The MRI guidelines provided here may significantly extend the MRI examination time or prevent some types of MRI examinations from being conducted on
Activa patients.
General Information on MRI
An MRI system produces three types of electromagnetic fields that may interact with implanted neurostimulation systems. All three of these fields are necessary to
produce an MRI image. Each of these fields can also produce specific but different types of interactions with implanted neurostimulator systems. These fields
include:
• Static Magnetic Field. This is a steady state non-varying magnetic field that is normally always ON, even when no scan is underway. In a 1.5 Tesla
MRI system, the static magnetic field is approximately 30,000 times greater than the magnetic field of the earth.
• Gradient Magnetic Field. This is a low-frequency pulsed magnetic field that is only present during a scan. The gradient magnetic field can induce
voltages onto the lead system that may result in unintended stimulation or functional interactions with the neurostimulator.
• RF Field. This is a pulsed radio frequency (RF) field that is only present during a scan. It can be produced by a variety of transmission RF coils such
as a whole body transmit coil or an extremity coil such as a transmit/receive head coil. Only a transmit/receive head coil should be used as the other RF
coils can expose more of the lead system to RF energy, thereby increasing the risk of excessive heating and thermal lesions possibly resulting in coma,
paralysis, or death.
MRI Interactions with Implanted Activa Systems
MRI/neurostimulation system interactions are various, and the risk to the patient can range from minimal to severe. These interactions include the following:
Heating – The MRI RF field induces voltages onto the lead system that can produce significant heating effects at the lead electrode-tissue interface or at the
location of any breaks in the neurostimulator lead system. Component heating from the MRI RF field is the most serious risk from MRI exposure. Failure to follow
these MRI recommendations can result in thermal lesions possibly resulting in coma, paralysis, or death.
Neurological Patient and Technical Services Department
November 2005 Page 20 of 27
Magnetic Field Interactions – Magnetic field interactions such as force and torque effects are produced by the static magnetic field. Any magnetic material will be
attracted to the static magnetic field of the MRI. The force and torque effects may produce movement of the neurostimulator that can be uncomfortable to the
patient, open a recent incision, or both. Activa System components are designed with minimal magnetic materials.
Induced Stimulation – Gradient magnetic fields may induce voltages onto the lead system that may cause unintended stimulation. The voltage of the induced
stimulation pulses is proportional to the time rate of change (dB/dt) of the gradient pulses, the effective loop area created by the neurostimulator lead system, and the
location of the lead system with respect to the gradient coils of the MRI.
Effects on Neurostimulator Function – The static, gradient, and RF fields of the MRI may affect the neurostimulator operation and programming. The static
magnetic field may cause the neurostimulator to turn ON or OFF if the neurostimulator uses a magnetically controlled switch that allows the patient to control
stimulation by the application of a handheld magnet. Additionally, the MRI RF, static, and gradient fields may temporarily affect or disable other functions, such as
telemetry or stimulation pulses. Parameters will need to be reprogrammed if the MRI causes a POR (Power On Reset) of the neurostimulator.
Image Artifacts and Distortion – The neurostimulation system components, particularly the neurostimulator, can cause significant imaging artifacts and/or
distortion of the MRI image, particularly if the neurostimulator components contain magnetic material. The neurostimulator can cause the MRI image to be
completely blocked from view (i.e., signal loss or signal "void") or severely distorted within several inches of the neurostimulator.
MRI Procedure
Scope
These MRI/neurostimulator exposure guidelines apply to Activa Systems comprising combinations of the following components:
• Neurostimulator Models: Itrel II 7424, Soletra 7426, Kinetra 7428
• Lead Extension Models: 7495, 7482
• Lead Models: DBS 3387, 3389
Supervision
A responsible individual such as an MRI radiologist or MRI physicist must assure these procedures are followed. If the MRI is operated by an MRI technician, it is
strongly recommended the responsible individual verifies that the MRI recommendations are followed.
Preparation
Do the following prior to performing an MRI examination on an Activa patient:
1. Inform the patient of the risks of undergoing an MRI.
2. Check if the patient has any other implants or conditions that would prohibit or contraindicate an MRI examination. Do not conduct an MRI examination if
any are found.
3. Verify that all proposed MRI examination parameters comply with the “MRI Operation Settings” on Table 12. If not, the parameters must be modified to
meet these requirements. If this cannot be done, do not perform an MRI.
4. If the patient has implanted leads but does not have an implanted neurostimulator, perform the following steps:
a. Wrap the external portion of the leads/percutaneous extensions with insulating material.
b. Keep the external portion of the leads/percutaneous extensions out of contact with the patient.
c. Keep the external leads/percutaneous extensions straight, with no loops, and running down the center of the head coil.
5. If the patient has an implanted neurostimulator, perform the following steps:
a. Review the neurostimulator with a clinician programmer and print out a copy of the programmed parameters for reference.
b. Test for possible open circuits by measuring impedance and battery current on all electrodes in unipolar mode (see Table 11). If an open circuit is
suspected, obtain an x-ray to identify whether the open circuit is caused by a broken lead wire. If a broken lead wire is found, do not perform an MRI.
Neurological Patient and Technical Services Department
November 2005 Page 2 1 of 27
Table 11. Measurement Values Indicating Possible Open Circuits
Neurostimulator
Impedance Battery Current
Itrel II Model 7424
>2000 :
<10 µA
Soletra Model 7426
>2000 :
<10 µA
Kinetra Model 7428
>4000 :
<15 µA
Warning: An MRI procedure should not be performed in a patient with an Activa System that has a broken lead wire because higher than normal
heating may occur at the break or the lead electrodes which can cause thermal lesions. These lesions may result in coma, paralysis, or death.
c. If the Activa System is functioning properly and no broken lead wires are found, program the neurostimulator to the settings provided in Table 12. Table 12.
Recommended Neurostimulator Settings for MRI
Parameter
Stimulation output
Setting
OFF (all programs)
Stimulation mode
Bipolar (all programs)
Amplitude
0 Volts (all programs)
Magnetic (reed) switch
Disabled (Kinetra Model 7428 only)
Other parameters
Do not change
MRI Operation Settings
Prior to the MRI examination, a responsible individual such as an MRI radiologist or MRI physicist must assure the examination will be conducted according to the
following MRI requirements. If standard MRI pulse sequences will be used, they must meet these requirements. If they do not, the pulse parameters must be
adjusted so that they comply with these requirements:
Warning: In-vitro testing has shown that exposure of the Activa System to MRI under conditions other than described in this guideline can induce excessive
heating at the lead electrodes or at breaks in the lead to cause lesions. These lesions may result in coma, paralysis, or death.
•
•
Use only a 1.5 Tesla horizontal bore MRI (do not use open sided or other field strength MRI systems).
Use only a transmit/receive head coil.
•
•
Contraindication: Implantation of an Activa Brain Stimulation System is contraindicated for patients who will be exposed to Magnetic Resonance
Imaging (MRI) using a full body transmit radio-frequency (RF) coil, a receive-only head coil, or a head transmit coil that extends over the chest
area. Performing MRI resulting in serious and permanent injury including coma, paralysis, or death.
Enter the correct patient weight into the MRI console to assure the head SAR is estimated correctly.
Use MRI examination parameters that limit the applied head SAR to 1/10 (0.1) W/kg or less for all RF pulse sequences.
Warnings
• Ensure
the SAR value is the value for head SAR. Some MRI systems may only display SAR, whole body SAR, or local body SAR. Make sure the
value being limited is for head SAR. Excessive heating may occur if the wrong SAR value is used.
Neurological Patient and Technical Services Department
•
November 2005 Page 22 of 27
If MRI parameters must be manually adjusted after the initial automatic MRI prescan, do not make any adjustments that will increase the SAR value.
Some MRI machines may not automatically update the displayed SAR value if manual adjustments are made. This may lead to higher than expected
temperature increases in the Activa System, particularly at the lead electrodes.
• Limit
the gradient dB/dt field to 20 Tesla/second or less.
Note: The recommendations provided are based on in-vitro testing and should result in a safe MRI examination of a patient with an implanted Medtronic Activa
System. However, due to the many variables that affect safety, Medtronic cannot absolutely ensure safety or that the neurostimulator will not be damaged. The user
of this information assumes full responsibility for the consequences of conducting an MRI examination on a patient with an implanted Activa System.
Prior to the MRI Examination
Prior to the scan examination, the responsible individual must verify the MRI examination parameters comply with these guidelines.
• Patients with implanted Activa Systems should be informed of the risks of undergoing an MRI.
• If possible, do not use sedation so the patient can inform the MRI operator of any heating, discomfort, or other problems.
• Instruct the patient to immediately inform the MRI operator if any discomfort, stimulation, shocking, or heating occurs during the examination.
During the MRI Examination
•
•
Monitor the patient both visually and audibly. Check the patient between each imaging sequence. Discontinue the MRI examination immediately if the
patient is unable to respond to questions or reports any problems.
Conduct the examination using only the MRI pulse sequence that the MRI radiologist or physicist has confirmed meets the MRI requirements above.
Post MRI Examination Review
• Verify that the patient is feeling normal.
• Verify that the neurostimulator is functional.
• Reprogram the neurostimulator to pre-MRI settings.
November 2005 Page 23 of 27
Neurological Patient and Technical Services Department
FROM MED TRONIC PAIN THERAPY, INFORMATION FOR PRESCRIBERS, APPENDIX B
MRI and neurostimulation therapy for chronic pain
Introduction
Medtronic recommends that you do not conduct an MRI examination of any part of the body on a patient using a radio-frequency (RF) transmit body coil.
If all of the instructions stated in this Appendix B are followed, MRI examinations of the head only using an RF transmit/receive head coil may be safely
performed.
It is important to read this information in its entirety before conducting an MRI examination on a patient with any implanted component of a Medtronic
neurostimulation system for chronic pain. These instructions do not apply to other implantable products or other devices, products, or items. Contact Medtronic at 800328-0810 if you have any questions.
Due to the number and variability of parameters that affect MRI compatibility, the safety of patients or continued functioning of neurostimulation systems exposed to
MRI cannot be absolutely ensured. MRI systems generate powerful electromagnetic fields that can produce a number of interactions with implanted components of the
neurostimulation system. Some of these interactions, especially heating, are potentially hazardous and can lead to serious injury or death. However, when all
instructions stated in this Appendix B are followed, MRI examinations of the head only may be safely performed. In addition, neurostimulation system components
can affect the MRI image, potentially impacting the diagnostic use of this modality. The following information describes the potential interactions and control
measures that should be taken to minimize the risks from these interactions.
The instructions in this Appendix B describe how to conduct a head-only MRI examination of a patient with a neurostimulation system implanted for chronic pain, using
a transmit/receive head coil of a 1 .5-Tesla horizontal bore MRI. MRI examinations of any other part of the body are not recommended, as these require the use of the
MRI RF transmit body coil, which may produce hazardous temperatures at the location of the implanted lead electrodes.
Warnings
MRI RF transmit body coil – Medtronic recommends that you do not conduct an MRI examination using an RF transmit body coil on a patient with any implanted
neurostimulation system component because the interaction of the MRI with the neurostimulation system may lead to serious injury or death. See the section “Risks
associated with MRI examination” on page 24.
MRI transmit/receive head coil – An MRI examination of the head only (no other part of the body) can be conducted safely using an RF transmit/receive head coil
when all instructions in this Appendix B are followed.
Limitations
• MRI should not be considered for patients with neurostimulation systems if other potentially safer diagnostic methods such as CT, x-ray, ultrasound, or
others will provide adequate diagnostic information.
•
•
These instructions apply only to Medtronic neurostimulation therapies for chronic pain for approved indications.
The instructions in this Appendix B apply to all Medtronic fully implantable neurostimulators, leads, and extensions used for chronic pain therapy.
Note: The instructions contained in this Appendix B are not applicable to MRI examinations of patients with radiofrequency (RF) neurostimulators.
Medtronic recommends physicians not prescribe MRI for a patient who has an implanted Itrel 3 Model 7425 Neurostimulator. The Itrel 3 Neurostimulator is
highly susceptible to reset or damage when subjected to an MRI examination. If reset, the neurostimulator must be reprogrammed. If damaged, the
neurostimulator must be replaced. The Itrel 3 Neurostimulator has an increased risk of induced electrical current, which may stimulate or shock the patient.
Contact Medtronic at 800-328-0810 for information about newer models or any updates.
Neurological Patient and Technical Services Department
November 2005 Page 24 of 27
•
The RF transmit/receive head coil must not cover any implanted system component.
•
If the patient has any other implants or products that prohibit or contraindicate an MRI examination, follow the instructions from the manufacturer. The
instructions in this Appendix B apply only to the Medtronic products listed above.
•
Do not conduct an MRI examination if the patient’s neurostimulation system has a broken lead wire, because higher than normal heating may occur at the
break or lead electrodes. Excessive heating can cause tissue damage and result in severe injury or death.
•
Physicians should not prescribe MRI for patients undergoing trial neurostimulation and having systems that are not fully implanted.
•
If the MRI targeted image area is near the neurostimulator, it may be necessary to move the neurostimulator to obtain an image, or use alternate imaging
techniques. MRI images may be severely distorted or image target areas can be completely blocked from view near the implanted neurostimulation system
components, especially near the neurostimulator.
•
Do not remove the neurostimulator and leave the lead system implanted as this can result in higher than expected lead heating. Excessive heating can
cause tissue damage and result in severe injury or death.
Risks associated with MRI examination – Exposing a patient with an implanted neurostimulation system or component to MRI may potentially injure the patient or
damage the neurostimulator. The known potential risks are as follows:
•
Induced electrical currents from the MRI to the neurostimulation system or component may cause heating, especially at the lead-electrode site, resulting in
tissue damage. Induced electrical currents may also stimulate or shock the patient.
Note: This warning applies even if only a lead or extension is implanted. Factors that increase the risks of heating and patient injury include, but are not
limited to, the following:
•
High MRI specific absorption rate (SAR) RF power levels
•
Low impedance leads or extensions (Medtronic product names or model numbers designated by a “Z,” an “LZ,” or “low impedance”)
•
MRI RF transmit/receive coil that is near or extends over the implanted lead system
•
Implanted lead systems with small surface area electrodes
•
Short distances between lead electrodes and heat-sensitive tissue
•
Exposure to gradients exceeding a dB/dt limit of 20 Tesla per second may result in overstimulation or shocking, particularly for unipolar-capable devices.
•
MRI may permanently damage the neurostimulator, requiring explant or replacement.
•
MRI may affect the operation of the neurostimulator. The MRI may also reset the parameters to power-on-reset settings, requiring reprogramming with the
clinician programmer.
•
The Itrel 3 Model 7425 Neurostimulator is highly susceptible to reset or damage when subjected to an MRI examination. If reset, the neurostimulator must be
reprogrammed. If damaged, the neurostimulator must be replaced. An Itrel 3 Neurostimulator also might exhibit unpredictable behavior if subjected to an
MRI examination.
The neurostimulator may move within the implant pocket and align itself with the MRI field, which may cause patient discomfort or a recent neurostimulator
implant incision to open.
Neurological Patient and Technical Services Department
November 2005 Page 25 of 27
Cautions
Patient interaction during MRI – If possible, do not sedate the patient so that the patient can provide feedback of any problems during the examination.
Monitor the patient during the MRI examination. Verify that the patient is feeling normal and is responsive between each individual scan sequence of the MRI
examination. Discontinue the MRI immediately if the patient becomes unresponsive to questions or experiences any heating, pain, shocking
sensations/uncomfortable stimulation, or unusual sensations.
MRI procedure using an RF transmit/receive head coil
Supervision
If all of the instructions stated in this Appendix B are followed, MRI examinations of the head using an RF transmit/receive head coil may be safely performed.
Prior to the MRI examination, an individual with the proper knowledge of MRI equipment such as an MRI radiologist or MRI physicist must ensure the MRI
examination will be conducted according to the information outlined in this Appendix B.
Note: Due to the additional requirements in these instructions, MRI examination time may be significantly extended.
MRI exposure requirements
Prior to an MRI examination, determine whether the patient has multiple active medical device implants (such as deep-brain stimulation systems, implantable
cardiac defribrillators, and others). The most restrictive MRI exposure requirements must be used if the patient has multiple active medical device implants.
Contact the appropriate manufacturers of the devices if you have questions.
If the following requirements cannot be met, do not proceed with the MRI examination.
•
Use only an RF transmit/receive head coil.*
•
Use only a 1 .5-Tesla horizontal bore MRI (do not use open-sided or other field strength MRI systems).
•
Enter the correct patient weight into the MRI console to ensure the head SAR is estimated correctly.
The MRI scan sequences must meet the following requirements. If they do not, the pulse parameters must be adjusted so that they comply with these
requirements.
•
Use MRI examination parameters that limit the head SAR to 1.5 W/kg or less for all RF pulse sequences.
•
Limit the gradient dB/dt field to 20 Tesla per second or less.
*Important: If you are unsure if your MRI has RF transmit/receive head coil capability or if it displays “head SAR”, check with your MRI manufacturer.
Note: The requirements provided are based on in-vitro testing and should result in a safe MRI examination of a patient with an implanted Medtronic
neurostimulation system when all instructions in this Appendix B are followed. However, due to the many variables that affect safety, the safety of patients or
continued functionality of neurostimulator systems exposed to MRI cannot be absolutely ensured. The user of this information assumes full responsibility for the
consequences of conducting an MRI examination on a patient with an implanted neurostimulation system.
Neurological Patient and Technical Services Department
November 2005 Page 26 of 27
Preparation for the MRI examination
Do the following prior to performing an MRI examination on a patient with an implanted neurostimulation component:
1. Inform the patient of all of the risks of undergoing an MRI examination as stated in this Appendix B.
2. If possible, do not use sedation so the patient can inform the MRI operator of any heating, discomfort, or other problems.
3. Instruct the patient to immediately inform the MRI operator if any discomfort, stimulation, shocking, or heating occurs during the examination.
4. Determine if the patient has any other implants or conditions that would prohibit or contraindicate an MRI examination. If you are unclear what implants
may be present, perform an x-ray to determine implant type and location. Do not conduct an MRI examination if any conditions or implants that would
prohibit or contraindicate an MRI are present.
5. Verify that all proposed MRI examination parameters comply with the “MRI exposure requirements” (refer to page 25). If not, the parameters must be
modified to meet these requirements. If parameters cannot be modified, do not perform an MRI.
6. If the patient has implanted leads but does not have an implanted neurostimulator, perform the following steps:
a. Wrap the external portion of the leads/percutaneous extensions with insulating material, such as dry gauze.
b. Keep the external portion of the leads/percutaneous extensions out of contact with the patient.
c. Keep the external leads/percutaneous extensions straight, with no loops, and running down the center of the head coil.
7. If the patient has an implanted neurostimulator, perform the following steps:
a. Review the neurostimulator with a clinician programmer and print out a copy of the programmed parameters for reference.
b. Test for possible open circuits by measuring impedance on all electrodes. An impedance measurement greater than 4000 ohms for the Synergy Plus+,
Synergy Compact+, Synergy Versitrel, Synergy, or Itrel 3 Neurostimulator indicates a possible open circuit. An impedance measurement greater than
3600 ohms for the Restore Neurostimulator indicates a possible open circuit.
c.
If an open circuit is suspected, obtain an x-ray to identify whether the open circuit is caused by a broken lead wire. If a broken lead wire is found, do
not perform an MRI examination.
Warning: Do not conduct an MRI examination if the patient’s neurostimulation system has a broken lead wire, because higher than normal heating may occur at
the break or lead electrodes. Excessive heating can cause thermal lesions and result in severe injury or death.
8. If the system is functioning properly and no broken lead wires are found, program the neurostimulator to the settings provided in Table 3.
Parameters
Table 3. Recommended neurostimulator settings for MRI examinations
Settings
Stimulation output
OFF (all programs)
Stimulation mode
Bipolar (all programs)
Amplitude
0 Volts (all programs)
Magnetic (reed) switch
Disabled (Itrel 3 Model 7425 only)
Other parameters
Do not change
Neurological Patient and Technical Services Department
November 2005 Page 27 of 27
During the MRI examination
•
Monitor the patient both visually and audibly. Check the patient between each imaging sequence. Discontinue the MRI examination immediately if the
patient is unable to respond to questions or reports any problems.
•
Conduct the examination using only the MRI pulse sequence that the MRI radiologist or physicist has confirmed meets the “MRI exposure requirements”
outlined in this Appendix B.
Post-MRI examination review
•
Verify that the patient feels normal.
•
Verify that the neurostimulator is functional.
•
Reprogram the neurostimulator to pre-MRI settings.