How Does the Vivistim System Work? Learn About the New Stroke Rehabilitation Device Approved By the FDA
Key takeaways:
The Vivistem System is a prescription medical device that may help improve arm and hand movements in certain people who have had an ischemic stroke.
This device works by using vagus nerve stimulation (VNS) alongside physical therapy exercises.
The FDA designated the Vivistim System as a breakthrough device.
In late August 2021, the FDA approved a medical device called the MicroTransponder Vivistim Paired VNS System — also known simply as the Vivistim System. Using a new technique, this device may help improve arm and hand movement in people who have had a stroke.
Strokes are common: about 800,000 people experience them in the U.S. every year. Ischemic strokes, which account for close to 90% of all strokes, occur when an artery (blood vessel) is blocked and cuts off part of the brain’s supply of blood and oxygen. A hemorrhagic stroke is when blood spills out of an artery into surrounding brain tissue.
Stroke complications are different for everyone, but they can lead to physical impairments, communication difficulties, brain damage, and death. Although many effects can be permanent, some can be improved through physical therapy exercises (also called stroke rehabilitation). The Vivistim System supplements these exercises and may help a person regain upper limb function after having an ischemic stroke.
Here, we’ll discuss what the Vivistim System is, how it works, and why its FDA approval is noteworthy.
What is the vagus nerve?
The Vivistim System works by stimulating — or interacting with — the vagus nerve. All nerves are important, and the vagus nerve is no exception.
The vagus nerve is the 10th of 12 different cranial nerves — nerves that link your body to your brain. It’s the longest cranial nerve, and it runs down to your gastrointestinal (GI) tract. Because the vagus nerve goes through so many areas of the body, it impacts many body functions. These include:
Tongue movement and speech
Swallowing and taste
Being able to feel sensations on certain parts of your skin
Involuntary (automatic) movements of the esophagus, lung, heart, and GI tract
Research has also shown that the vagus nerve can impact certain brain chemicals, like acetylcholine and norepinephrine. Alterations of these brain chemicals in the cortex — a portion of the brain — may help improve physical movements in the post-stroke recovery process. More on this next.
What is the Vivistim System?
The Vivistim System isn’t a medication — it’s a prescription-only medical device. A medical device is a piece of technology or equipment that can be used to diagnose, prevent, or treat a disease, condition, or injury.
The Vivistem System contains four parts — an implant (implantable pulse generator), a silicone wire (lead) that connects the implant to the vagus nerve, a wireless transmitter, and computer software.
The implant is rather small — it’s 48 millimeters (mm) wide, 62 mm tall, and 12 mm thick — and it’s put in the body through a minor surgical procedure (For reference, 25 mm equals about 1 inch.). The implant is placed under the skin in the chest, the wire runs under the skin from the chest to the neck, and the wire attaches onto the vagus nerve. The wireless transmitter helps with system communication, and the computer software tells the implant when it should and shouldn’t work.
The Vivistem System may help improve the recovery process for people who have had an ischemic stroke, and it’s intended to be used in combination with stroke rehabilitation exercises. These exercises can be different for everyone, and they can occur in a variety of places, such as a hospital, long-term care facility, or your home. No matter the location, this device may help promote the intended benefits of these exercises.
The Vivistem System is also considered to be a digital medicine — a treatment category that uses software to help improve healthcare.
How does it work?
The Vivistem System works by using vagus nerve stimulation (VNS). VNS isn’t a new technology, but this is the first time it’s been approved to help treat people who have had a stroke.
For stroke recovery purposes, VNS works by sending mild electrical impulses to the vagus nerve to help improve muscle plasticity, or the muscle’s ability to change its structure or function if it’s exposed to something, such as electric impulses. In other words, VNS can help “retrain” a muscle to function more ideally.
More specifically, VNS raises the amount of chemicals like acetylcholine and norepinephrine in the brain. When the amount of these brain chemicals are higher while performing physical therapy exercises, the muscles undergoing the exercises may be more likely to remember the specific training being performed.
Computer software, controlled by a healthcare professional, tells the Vivistim System when it should send these electrical impulses. It’s usually used under the direct supervision of a healthcare professional, but some people can be trained to use it at home as well.
Why is it important?
This is the first time that VNS has been FDA-approved to help people who have experienced an ischemic stroke. Since strokes affect so many people, any opportunity to better improve the lives of those who have had a stroke is highly desirable. Because of this, the FDA designated the Vivistem System as a breakthrough device to help speed up its review process.
Currently, it’s estimated that 40% of people experience moderate-to-severe limitations caused by their stroke. Also, about 60% of people have difficulty with arm and hand movement that lasts more than 6 months after their stroke. There’s hope that this device may help alleviate limitations like these.
Aside from stroke, VNS has been FDA-approved for more than 20 years to help treat people with conditions like epilepsy (seizures) and treatment-resistant depression. This approval helps show how VNS may be useful for multiple possible health conditions.
When will it be available?
In some parts of the U.S., the Vivistem System will likely be available by the end of 2021. But it will take a little longer for the device to become available more widely across the nation. It’s expected that it will be available in most U.S. markets by the end of 2022.
If you or a loved one had an ischemic stroke and have questions about the Vivistem System or its availability, please reach out to your healthcare provider.
Does it work for everyone who’s had a stroke?
The Vivistem system can’t be used by everybody, but it can still be used by many people who have had a stroke.
The FDA’s decision to approve the Vivistem System came from one main study — fittingly called the VNS-REHAB trial. The study was rather small, including 108 people from the U.S. and U.K. About half received VNS as intended (study group), and the other half received very low amounts of it (control group). Both groups also received physical therapy at the same time.
The initial study was conducted over a period of 6 weeks, and everyone was monitored routinely afterwards for 3 months. Using a specific measurement tool that shows how severe arm and hand impairments are after a stroke, the study found that about 47% of people who received VNS as intended saw a clinical benefit after 3 months, compared to almost 24% in the control group.
Of note, the Vivistim System is only intended to be used by people who have developed moderate-to-severe physical limitations from an ischemic stroke. It shouldn’t be used to treat mild physical limitations. It also cannot be used to treat people who have had a hemorrhagic stroke.
The bottom line
The Vivistem System was recently FDA-approved to help improve arm and hand movements in people who have had an ischemic stroke. It’s a medical device designed and intended to be used alongside physical therapy exercises.
It’s not available quite yet, but it’ll likely be available in parts of the U.S. later this year. If you have any questions or concerns about the Vivistem System, please reach out to your healthcare provider.
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