This information on MRI pertains to the following Medtronic Neuromodulation products:
InterStim®: model number 3023
InterStim II®: model number 3058

Magnetic resonance imaging (MRI) – MRI is not recommended for a patient who has any implanted component of a neurostimulation system. Exposing a patient with an implanted neurostimulation system or component to MRI may potentially injure the patient or damage the neurostimulator. Clinicians should carefully weigh the decision to use MRI in patients with an implanted neurostimulation system, and note the following:

• 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) Radio Frequency (RF) power levels.
–  MRI RF transmit coil that is near or extends over the implanted lead.
–  Implanted leads with small surface area electrodes.
–  Short distances between lead electrodes and tissue that is sensitive to heat.

• An MRI may permanently damage the neurostimulator, requiring it be removed or replaced.
• An MRI may affect the normal operation of the neurostimulator. An MRI can also reset the neurostimulator to power-on-reset values requiring reprogramming by a trained InterStim clinician.
• The neurostimulator can move within the implant pocket and align with the MRI field, resulting in discomfort or reopening of a recent implant incision.

In addition, the image details from MRI may be degraded, distorted, or blocked from view by the implanted neurostimulation system.

Patients treated with MRI should be closely monitored and programmed parameters verified
upon cessation of MRI.

Effects of 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.

Theft detectors and security screening devices – Theft detectors found in retail stores,
public libraries, etc., and security screening devices found in airports, government buildings,
etc., occasionally may cause intermittent stimulation or a momentary increase in stimulation
intensity. When they pass through these devices, some patients may perceive intermittent
stimulation as switching their neurostimulation system on and off. It is also possible that
patients, especially those with low stimulation thresholds, may experience a momentary
increase in their perceived stimulation when they pass through these devices. Higher levels
of stimulation have been described as uncomfortable (“jolting” or “shocking”) by some
patients. In rare situations, such occurrences have caused patients to fall, potentially causing personal injury.

Rx Only
2006