FDA Warns of Programmable CSF Shunts and Magnetic Field Interference with Implanted Hearing Devices
The U.S. Food and Drug Administration (FDA) has issued a letter to health care professionals to increase awareness about potential complications in patients implanted with both programmable cerebrospinal fluid (CSF) shunt systems and some hearing implants that contain magnets, such as cochlear implants, bone conduction hearing devices, or middle ear hearing devices. Magnetic interactions between these devices may occur when implanted in close proximity to each other. These interactions may lead to unintended changes to the programmable CSF shunt valve settings.
If magnetic interactions inadvertently change the programmable CSF shunt valve settings, then over- or under-drainage of CSF may occur. Patients may experience symptoms such as altered mental status, headaches, lethargy, irritability, vomiting, changes in vision, and difficulty walking. If left untreated, symptoms could progress to include loss of consciousness, seizures, hemorrhage, or even death.
The FDA is recommending the following:
- Educate patients and caregivers about this potential risk and be sure they know when to have their programmable CSF shunt valve checked, what symptoms are associated with potential over- or under-drainage of CSF, and when to contact you.
- Check the programmable CSF shunt valve setting after placement or adjustment of other devices that contain magnets to ensure that the setting has not changed. Only a trained clinician, such as a neurosurgeon, should check the shunt valve setting and adjust the setting, if necessary.
- Consider the location of placement of the programmable CSF shunt valve if the patient has other implanted devices known to contain magnets in close proximity. For example:
- Consider placing the programmable CSF shunt valve on the contralateral side of a cochlear implant or implantable bone conduction hearing device, if the patient's anatomy and clinical picture permit such a strategy.
- For patients requiring bilateral hearing implants, which use magnets and a programmable CSF shunt, the implanting physician should position the CSF shunt valve and the ipsilateral hearing implant at a maximum distance from one another.
- Contact the applicable device manufacturer for further information.
Providers are encouraged to report all adverse events or suspected adverse events experienced with programmable CSF shunts and potential magnetic interference. Voluntary reports can be submitted through the MedWatch, the FDA’s Safety Information and Adverse Event Reporting Program.
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