The U.S. Food and Drug Administration (FDA) approved the MicroTransponder Vivistim Paired VNS System (Vivistim System), a first-of-its-kind, drug-free rehabilitation system intended to treat moderate to severe upper extremity motor deficits associated with chronic ischemic stroke—a stroke caused by a blockage of blood flow to the brain with long-lasting symptoms—using vagus nerve stimulation (VNS) according to the FDA release.
“People who have lost mobility in their hands and arms due to ischemic stroke are often limited in their treatment options for regaining motor function” said Christopher M. Loftus, M.D., acting director of the FDA’s Center for Devices and Radiological Health’s Office of Neurological and Physical Medicine Devices. “Today’s approval of the Vivistim Paired VNS System offers the first stroke rehabilitation option using vagus nerve stimulation. Used alongside rehabilitative exercise, this device may offer benefit to those who have lost function in their upper limbs due to ischemic stroke.”
The Vivistim System is intended to be used, along with post-stroke rehabilitation therapy, in patients who have had ischemic stroke, to electrically stimulate the vagus nerve—a nerve that runs from the brain down to the abdomen—to reduce deficiencies in upper limb and extremity motor function and to improve patients’ ability to move their arms and hands.
To use the Vivistim System, an implantable pulse generator (IPG)—which generates a mild electrical pulse—is implanted just under the skin in the chest of the patient. Attached to the IPG is a lead wire that is implanted under the skin and leads up to electrodes that are placed on the left side of the neck where the vagus nerve is.
Accompanying the implantable components are clinician software preloaded onto a laptop and a wireless transmitter to be used only by a health care provider. The software allows a healthcare provider managing a patient’s rehabilitation to input the appropriate settings on the IPG, including amplitude, frequency and pulse width for the stimulation. It also records stimulation history, movements performed and information about the IPG. The wireless transmitter communicates adjustments to the IPG settings made using the software.
The Vivistim System, a prescription device, may be used in both clinical and at-home settings to provide VNS. If it is to be used during home rehabilitation exercises, the software and the wireless transmitter are not used by the patient. However, the patient is supplied with a magnet that can be passed over the IPG implant site to activate the IPG to begin a 30-minute stimulation session during rehabilitative exercise. When directed by a physician and with appropriate programming to the IPG, patients are trained on how to use the Vivistim System at home, as well as its safety features, to avoid any unwanted electrical stimulation.
Effectiveness for the Vivistim System was measured using the Upper Extremity Fugl-Meyer Assessment (FMA-UE), a stroke specific measure of motor impairment. Progress was measured as an increase in motor function from baseline after six weeks of therapy. Patients in the treatment group had an average score increase of 5 points, whereas patients in the control group had an average score increase of 2.4 points. Additionally, 47.2% of those in the treatment group saw an improvement of 6 or more points in the FMA-UE score 90 days post-therapy as compared with 23.6% in the control group.
The MicroTransponder Vivistim Paired VNS System is manufactured by MicroTransponder Inc.
