A new therapy involving vagus nerve stimulation (VNS) combined with rehabilitation has been approved to treat chronic moderate to severe upper limb motor deficits after ischemic stroke, the FDA said Friday.
“Today’s approval of the Vivistim Paired VNS System provides the first option for stroke rehabilitation using vagus nerve stimulation,” said Christopher Loftus, MD, acting director of the FDA’s Center for Devices and of the office of neurological and physical medical devices of radiological health. “Used alongside rehabilitation exercises, this device may be of benefit to those who have lost upper limb function due to ischemic stroke. “
Vivistim is the first system of its kind approved to help stroke patients move their arms and hands. It stimulates the vagus nerve with an implantable pulse generator placed just under the skin in the chest. Attached to the pulse generator is a wire that leads to electrodes placed on the left side of the neck.
The FDA decision was based on the pivotal VNS-REHAB trial of 108 patients with moderate to severe arm weakness at least 9 months after ischemic stroke. Participants were randomized to a study (53 patients) or control (55 patients) group; each was instructed to perform 300-400 physiotherapy exercises for 90 minutes a day, three times a week for 6 weeks.
The control group received a very low level of VNS for the first five of the 300-400 exercises and no stimulation for the remainder of each session. The treatment group received the appropriate amount of VNS throughout all of the 90-minute sessions.
At 6 weeks, the treatment group showed an increase in mean score of 5 points on the Fugl-Meyer Upper Limb Assessment (FMA-EU), a measure of stroke-specific motor impairment. The control group had an average score increase of 2.4 points. 90 days after in-clinic treatment, 47.2% of the treatment group saw an improvement of 6 points or more on the FMA-UE, compared to 23.6% of controls.
Adverse events included dysphonia, bruising, falls, general hoarseness, general pain, hoarseness after surgery, bad mood, muscle pain, fractures, headache, rash, dizziness, throat irritation, urinary tract infections and fatigue, the FDA said.
Patients should discuss their medical history with their health care provider: other concomitant forms of brain stimulation; treatment of current diathermy, depression or suicidality; schizophrenia, schizoaffective disorder or delusional disorder; rapid cycling bipolar disorder; previous brain surgery or central nervous system injury; progressive neurological diseases other than stroke; heart abnormalities; respiratory illnesses or disorders; ulcers; vasovagal syncope; and pre-existing hoarseness.
The implantable components of the Vivistim system come with preloaded clinician software on a laptop computer and a wireless transmitter for use only by a healthcare provider. The system can also be used at home with a magnet that can be passed over an implanted pulse generator.
Vivistim, a prescription device, is not approved for any other use, the FDA added, and should not be used in patients with vagotomy. The system is manufactured by MicroTransponder.