New Implant No Longer Dangerous in MRI

3D rendering of an MRI machine.
MRIs are medical imaging systems used to diagnose health conditions. (Image credit: MRI scan via Shutterstock)

For patients suffering intense pain that isn't helped by the use of drugs or other treatments, a new device that can be surgically implanted near the spinal cord may offer relief.

Doctors have been implanting such spinal cord stimulators for years, but the new device has a unique feature — unlike most other metal devices, it can safely be used in an MRI machine, which means that people with the implant who need to also undergo MRI scans (which is not uncommon for patients with disabling pain) — can do so.

Last week, one of the first patients in the United States to have the device implanted since it was approved by the Food and Drug Administration underwent surgery at the Ohio State University Wexner Medical Center.

Neurosurgeons Dr. Ali Rezai and Dr. Milind Deogaonkar performed the surgery on a 78-year-old patient who suffered from intense foot pain on Aug. 5.

"The new system has eliminated hazards of MRI; it's an exciting development that we have been waiting for a long time," Rezai said. [10 Science Discoveries to Be Thankful for ]

Patients with the new generation of spinal cord stimulators can undergo MRI scans. (Image credit: © 2013 Medtronic, Inc.)

The surgeons implanted the device just outside the spinal cord, where it sends tiny electrical pulses to block the pain signals to the brain. Instead of pain, patients feel a tingling sensation from the neurostimulation in the areas of the body where they used to feel pain.

Most other electronic and metal devices, such as brain stimulators or cochlear implants, are dangerous to use in an MRI machine, since the devices can heat up, move and tear the tissue when placed in the strong magnetic field that MRI machines induce.

"MRI examinations are necessary and routinely performed for diagnosis and clinical care. It's very likely that a patient with chronic pain, spinal disease, neurological and orthopedic disorders will require an MRI scan," Rezai said.

People who have spinal cord implants that are not MRI-compatible can get CT scans instead of MRIs, but getting too many CT scans can be dangerous because of the radiation exposure.

The new implants, called SureScan neurostimulation systems, have a shield layer that catches the energy of the MRI machine and disperses it along the length of the device, reducing the risk of the device overheating, according to the manufacturer Medtronic Inc.

"The main concern is the radiofrequency pulses induced by the MRI machine, which are absorbed by the wiring and are concentrated at the electrodes," said Steve Manker, who was involved in the development of the technology at Medtronic. "This could cause the electrodes to heat up and damage the tissue."

The stimulator is also built using minimal magnetic material, so it is less likely to be pulled on by the MRI machine's magnetism.

Once implanted in the body, patients can control the device remotely to adjust the electrical stimulation in a way that is most comfortable for them. Doctors can also use the remote control to turn off the device before taking an MRI scan, so the machine does not cause irregular signaling in the device.

Medtronic said it doesn't discuss costs of their devices for competitive reasons. However, the total payment Medicare allows ranges from $25,000 to $34,000, depending on the system selected by the physician based on the patient's needs, a representative for the company said. This cost includes the hospital and physician payments for both the test stimulation and implantation procedures.

Email Bahar Gholipour. Follow LiveScience @livescienceFacebook & Google+. Original article on Live Science.

Bahar Gholipour
Staff Writer
Bahar Gholipour is a staff reporter for Live Science covering neuroscience, odd medical cases and all things health. She holds a Master of Science degree in neuroscience from the École Normale Supérieure (ENS) in Paris, and has done graduate-level work in science journalism at the State University of New York at Stony Brook. She has worked as a research assistant at the Laboratoire de Neurosciences Cognitives at ENS.