Axonics MRI Patient Guidelines User Guide

Axonics MRI Patient Guidelines

GLOSSARY

• For MRI Examinations Using a Whole-Body RF Transmit CoilMR Conditional – an item with demonstrated safety in the MR environment within defined conditions, including conditions of the static magnetic field, the switched gradient magnetic field and the radio frequency fields. Additional conditions, including specific configurations of the item, may be required.
• MR Unsafe – an item which poses unacceptable risks to the patient, medical staff, or other persons within the MR environment.
• – For USA audiences only.
• ACR Zone – zones of an MR site that denote areas with various MR safety levels, as defined by the American College of Radiology
• MRI – Magnetic Resonance Imaging.
• Sacral Neuromodulation (SNM) – a type of electrical stimulation therapy that uses mild electrical pulses to stimulate the sacral nerve located in the pelvic region.

Product Information

Axonics SNM System
The Axonics Sacral Neuromodulation (SNM) System is a medical device that helps treat overactive bladder, fecal incontinence, and urinary retention. It is an MR Conditional device, which means that patients with the Axonics SNM System can safely have MRI examinations of any body part under certain conditions.

What is Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) is a technique used to create pictures of the internal structures of the body. Unlike an X-ray exam, it does not use radiation. Instead, it uses a large magnet, radio waves, and a computer to create pictures of body structures and organs.

CAN I HAVE AN MRI

Patients with an implanted Axonics Sacral Neuromodulation (SNM) System may have an MRI scan of any body part under certain conditions. Consult with your doctor to determine if you are eligible for MRI examination. You are required to discuss with your doctor if you have any other device(s) implanted. Possible implanted devices include:

• Pacemaker or implantable cardioverter-defibrillator (ICD)
• Some aneurysm clips
• Cochlear implants
• Orthopedic prostheses (e.g., hip implant)
• Other neurostimulators
• Stents
• Metal plates, pins, or screws
• Dental implants

An MRI requires the patient to lie still during the exam. You should inform the MRI technologist before the MRI procedure:

• If you are pregnant or suspect you are pregnant
• If you are breast feeding at the time of the scheduled procedure
• If you are having a fever

MRI SAFETY INFORMATION

The Axonics SNM System is an MR Conditional device. This means that patients with the Axonics SNM System can safely have MRI examinations of any body part under certain conditions. The conditions for MRI scans will vary with the type of transmit coil. Always obtain the latest MRI guidelines. Refer to the contact information on the last page of this manual, or go to www.axonics.com/patients/mri.

MR Conditional Devices
Non-clinical testing has demonstrated that the Axonics SNM System implant, i.e., the Neurostimulator (Model 1101) and Tined Lead (Model 1201/2201), is MR Conditional. A patient with this device can be safely scanned in an MR system meeting the following conditions:

• Static Magnetic Field Strength (B0)
• Type of Nuclei
• MR Scanner Type
• B0 Field Orientation
• Maximum Spatial Field Gradient
• Maximum Slew Rate
• RF Transmit Coil Type
• RF Receive Coil Type

A patient implanted with the Axonics SNM System may be safely scanned at any body part, including the head and extremities, at 1.5T or 3T MRI using a whole-body RF transmit coil under these conditions. Failure to follow these conditions may result in injury to the patient.

For MRI Examinations Using a Whole-Body RF Transmit Coil
A patient implanted with the Axonics SNM System may be safely scanned at any body part, including head and extremities, at 1.5T or 3T MRI using a whole- body RF transmit coil under the following conditions. Failure to follow these conditions may result in injury to the patient.

Stimulation OFF, and Specified implant locations only
Static Magnetic Field Strength (B0)| 1.5T and 3T
Type of Nuclei| Hydrogen/Proton Only
MR Scanner Type| Cylindrical
B0 Field Orientation| Horizontal
Maximum Spatial Field Gradient| 2500 gauss/cm (25 T/m)
Maximum Slew Rate| 200 T/m/s per axis
RF Transmit Coil Type| Whole-Body
RF Receive Coil Type| Any type (e.g., surface array coil, head receive only coil, knee receive only coil)
Operating Mode| Normal Operating Mode
RF Conditions| For 1.5T Scanner : Whole-body SAR ≤ 2 W/kg

RF Excitation: Circularly Polarized (CP)

For 3T Scanner : B1+rms ≤ 2 μT; for MRI scanners that do not report B1+rms, limit Whole-body SAR ≤ 1.6 W/kg

RF Excitation: Circularly Polarized (CP) or Multichannel-2 (MC-2)

Scan Duration and Wait Time| Maximum 30 minutes of continuous scan time is allowed, followed by a wait time of 5 minutes if this limit is reached.
Scan Regions| Any body part is acceptable (e.g., head, extremities, stomach, pelvic region)
Image Artifact| The presence of the Axonics SNM System may produce an image artifact. Some manipulation of scan parameters may be required to compensate for the artifact.

Please consult with your Healthcare Provider (HCP) and the MRI technologist to make sure that the specific conditions above are met before MRI examination.

For MRI Examinations Using a Detachable Head, Upper Extremity, or Lower Extremity RF Transmit/Receive Volume Coil
A patient implanted with the Axonics SNM System may be safely scanned at the head or upper/lower extremity at 1.5T or 3T MRI under the following conditions. Failure to follow these conditions may result in injury to the patient.

–   Detachable Upper Extremity RF Transmit/Receive Volume Coil

–   Detachable Lower Extremity RF Transmit/Receive Volume Coil

Operating Mode| Normal Operating Mode or First Level Controlled Operating Mode
Scan Duration| There is no limit on scan duration
Scan Regions| Head, Upper or Lower Extremity
Image Artifact| No image artifact should be seen from a head or extremity MRI scan.

Illustrated in Figure 3-3 are typical use scenarios of detachable RF transmit/receive volume coil. Other scanning scenarios are also permissible according to MR scanner/coil manuals. For example, an MRI scan of the ankle with a detachable lower extremity RF transmit/receive volume coil or an MRI scan of the upper arm with a detachable lower extremity RF transmit/receive volume coil in the superman posture is permissible given the aforementioned scan conditions are met. Please consult with your Healthcare Provider (HCP) and the MRI technologist to make sure that the specific conditions above are met before MRI examination.

MR Unsafe Devices
The external components of the Axonics SNM System, including the Clinician Programmer, Remote Control, Charger and Dock, and External Trial System (External Pulse Generator and percutaneous leads and cables) are MR Unsafe (Figure 3-4). These devices must NOT be brought into the MR scanner room (ACR Zone IV).

POSSIBLE RISKS OF MRI WITH THE AXONICS SNM SYSTEM

While the Axonics SNM System is designed to be MR Conditional, there are still some risks associated with MRI scans. These risks include:

• Injury to the patient due to improper positioning in the MRI scanner
• Overheating of the device during the MRI scan
• Disruption of the device’s function during the MRI scan

Non-clinical testing has shown that patients with the Axonics SNM System can safely have MRI when the conditions for safe MRI described in this document are followed. However, there may be some risks of performing MRI when you have an implanted SNM System. Possible risks include:

• Heating of the implant
• Unintended stimulation
• Image distortion and artifacts
• Magnetic field interactions
• Device malfunction or damage

1. Heating of the Implant
   MRI may cause the implant to become hot. However, if the conditions for safe MRI are followed, this heating is minimal. If the specific MRI conditions are not followed, heating of the implant could damage the sacral nerve and/or surrounding structures. If the site of your implant feels hot during MRI, inform the MRI technologist immediately and then contact your doctor.

2. Unintended Stimulation
   MRI may cause unintended stimulation from the implant. This unintended stimulation may be uncomfortable (e.g., tingling, shocking, or jolting). However, if the conditions for safe MRI are followed, such stimulations may not happen. If you feel any uncomfortable stimulations during MRI, inform the MRI technologist immediately and then contact your doctor.

3. Image Distortion and Artifacts
   Some level of image distortion and artifacts can result from an MRI scan at the site of the device. The MRI technologist will select MRI settings that minimize these effects. However, there should be minimal image distortion when taking MR images of areas away from the device. No image distortion or artifacts should be seen from an MRI head and extremity scans.

4. Magnetic Field Interactions
   The magnets used in MRI may cause the Neurostimulator to shift or move slightly within the implant pocket. This may cause stress to tissues and/or the lead. As a result, you may feel a slight tugging sensation at the site of your implant. If you feel uncomfortable while in the MRI, inform the MRI technologist immediately.

5. Device Malfunction or Damage
   Tests in various MRI systems were conducted. These tests did not cause any damage to, or malfunction of, the implant. If the implant malfunctions or becomes damaged, it may result in nerve damage and other associated problems. If you feel any stimulation or discomfort during MRI, inform the MRI technologist immediately and then contact your doctor.

Product Usage Instructions

If you have an implanted Axonics SNM System and need an MRI scan, consult with your doctor to determine if you are eligible for MRI examination. You are required to discuss with your doctor if you have any other device(s) implanted.
Before the MRI procedure, inform the MRI technologist that you have an implanted Axonics SNM System. The Axonics SNM System product manuals provide detailed information about non-MRI aspects of implantation, programming, charging, and use of the components of the Axonics SNM System.
Always obtain the latest MRI guidelines for safe use of the Axonics SNM System during an MRI scan. Refer to the contact information on the last page of the product manual, or visit www.axonics.com/patients/mri for more information.

MRI GUIDELINES

The guidelines for MRI scans are based on non-clinical tests conducted on the implantable Axonics SNM System. Precautions are to be taken before, during, and after MRI scan. Talk to your MRI technologist or your doctor should you have any questions or concerns.

Before Starting MRI Scan

• Consult your doctor and MRI technologist to determine if you are eligible for MRI scan.

• Inform your doctor and MRI technologist if you have multiple Axonics SNM devices or any other medical device(s) implanted, such as a pacemaker, drug pump, hip prosthesis, stent, etc.

• Inform your doctor and MRI technologist if you think you have any the following conditions with your device: a broken lead, lead disconnection from the neurostimulator, a partially implanted lead, a malfunctioning neurostimulator, a neurostimulator implanted at an area other than posterior hip or upper buttock, or a neurostimulator with open or low impedances (indicating a short circuit) on any electrodes. Do not perform MRI body scan if any of these conditions apply.

• Your MRI technologist may also give you MRI Patient Guides and Instructions. Make sure that you fully comply with those. Discuss with your MRI technologist or your doctor if you have any concerns.

• Bring the most up-to-date patient ID card to all MRI appointments.

• Bring your patient Remote Control to all MRI appointments. Do not bring the patient Remote Control into the MR scanner room.

• For MRI using detachable head, upper extremity, or lower extremity RF transmit/receive volume coils, make sure that the Neurostimulator stimulation is turned OFF. Refer to your Remote Control Manual on how to turn your stimulation off.

• For MRI using whole-body RF transmit coil, check the device to confirm it is ready for MRI body scan with the following steps:
  Note: If you have a patient Remote Control manufactured before May 1st, 2020, whole-body MRI readiness check will need to be performed by the doctor or MRI technologist using the Clinician Programmer.

  1. Push “Connect” on the patient Remote Control to connect to Neurostimulator.
     Note: The Stimulation Level lights will show the current stimulation amplitude.

  2. Turn stimulation OFF by pressing and releasing the down arrow until all Stimulation Level lights are off.
     Note: Check that the Stimulator Battery Status light is green prior to the MRI scan. If the Stimulator Battery Status light is flashing orange or is solid orange, charge the Neurostimulator so the battery light is green prior to the MRI scan. Refer to the Charging System manual for charging instructions.
     Note: If the red System Error light is on and solid (not flashing), the System needs to be checked prior to an MRI scan.

  3. To check MRI readiness, press and hold the down arrow for 5 seconds.
     Note: The Active Program lights will flash back and forth, indicating MRI readiness check is in progress. It is normal for a sensitive patient to experience mild stimulation during the check. Once the check is complete, the patient Remote Control will vibrate.

  • a. If Stimulation Level lights #3, 4, and 5 are ON, the SNM device is ready for whole-body MRI.
  • b. If the System Error light is red, the SNM device is NOT eligible for whole-body MRI.

• Make sure you remove any external metallic objects before entering the MRI room.

• Do not carry any external devices associated with the Axonics SNM System, such as the Remote Control, Charger or Dock etc., into the MR Scanner room.

During MRI Scan

• You may feel slight tugging, vibration, warming, and/or tapping in the area where the Neurostimulator is located during the MRI scan. If those feelings cause discomfort, you should let the MRI technologist know immediately.
• If you are not feeling well for any other reasons prior to or at the time of MRI scanning, please inform your MRI technologist.

After MRI Scan

• After the MRI scan, turn the stimulation back on with the Remote Control. Refer to your Remote Control Manual on how to turn your stimulation back on.
• If you feel any changes in stimulation after an MRI, you should contact your doctor and turn the stimulation off, if uncomfortable.

Axonics, Inc.
Irvine, CA 92618 (USA)
www.axonics.com
Tel. +1-877-9AXONICS (+1-877-929-6642)
Fax +1-949 396-6321

For USA audiences only
(01/13/2022)
All Rights Reserved. Copyright © 2022.
Axonics, Inc.
110-0093-001rW

References

• Axonics® Therapy | Get Your Bladder Back
• Axonics® Systems Sacral Neuromodulation MRI Device Safety
• Patient Tools, Resources, & Guides | Axonics®
• Axonics® Therapy | Get Your Bladder Back
• Patient Tools, Resources, & Guides | Axonics®

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