Warning on Diathermy and Implanted Leads
FDA Patient Safety News: Show #13, March 2003

In a previous broadcast, we alerted you to the danger of using diathermy to treat patients who may have metallic leads from neurostimulator devices implanted in their bodies. Two patients with these implanted devices died when they later received diathermy treatments because of the excessive heat generated in the tissue surrounding the metal leads.

We’re now expanding the warning to include any implanted metallic lead in the patient’s body. Among the many implanted devices that may use metallic leads are cardiac pacemakers and defibrillators, cochlear implants, bone growth stimulators, and deep brain, spinal cord, and other nerve stimulators.

The warning covers any form of microwave diathermy or radiofrequency diathermy (which is also called shortwave diathermy). These are widely used by physicians, dentists, physical therapists, chiropractors and sports therapists. The warning does not include ultrasound diathermy.

FDA’s Public Health Notification notes that the danger can occur even when the diathermy device is in the non-heating mode, which you might not expect. Also, the danger exists even when the implanted device isn’t turned on. And it’s still there after the implant has been removed from the patient’s body, as long as the metal leads are left in—which often happens.

The Notification urges health care professionals who implant devices with metallic leads to explain to the patient what diathermy is, and stress that they should not receive shortwave or microwave diathermy.

And it urges health care professionals who administer shortwave or microwave diathermy to always ask the patient about possible implants. If the patient has an implanted lead, diathermy should not be used, even if the implant is turned off. If the patient says that he or she has had an implant that’s been removed, don’t use diathermy unless you’re absolutely certain that any metallic leads have also been removed.

Additional Information:

FDA Public Health Notification: Diathermy Interactions with Implanted Leads and Implanted Systems with Leads.

FDA Patient Safety News is available at www.fda.gov/psn