Brief Answer:
The Vagus N. and VNS implants

Detailed Answer:
Hi, Thanks for coming to HealthCareMagic. I would be happy to help you learn about the Vagus Nerve and Vagal Nerve stimulators. Lets start with the Vagus nerve.

Now to understand the Vagus nerve, you've first got to know a few terms. The first is "Parasympathetic nervous system"

Now what does that mean.. Well, our Nervous system is divided into different parts, There is the Central... (the brain and spinal cord).... the Peripheral.... (all the nerves that snakes through our bodies supplying information to the brain and carrying orders to our muscles and glands.

And finally the Autonomic Nervous System (ANS). As the name implies, This part of the nervous system works on its own. It works on its own and it controls basic functions like the movement of food through the digestive system, regulation of heart rate and breathing, sweating etc. Stuff that is NOT under conscious control.

Now the ANS is further subdivided into the SYMPATHETIC and the PARASYMPATHTIC nervous systems. I'm not going to go into to much of what is going on in this system, but suffice to say that they Balance each other out. The Sympathetic system works in balanced opposition to the parasympathetic for the most part (very Yin XXXXXXX type stuff). So for example if the Sympathtic system makes you break out into a sweat and increases your heart rate.. the Parasymp system will stop the sweating and calm your heart down.

The Vagus nerve is the Primary conveyance of PARASYMPATHTIC system information to the body and the the brain. Its the nerve which slows things down, decreases muscle tone, slows digestion and basically helps your body go into a low energy self repair state.

The ascending fibers of the Vagus nerve are what your surgeon would be interested in because that's what the stimulation device has to get wired too. I'm really sorry but i have no way of sending you pictures. The system does not allow that. If you google for the branches of the vagus nerve you should get the right pictures though.

Now on to Vagus Nerve stimulation:

What we are trying to do here is use the effects of the Parasympathetic system and calm the brain down.. ie decrease the seizure stimuli being generated in the brain.

If you are looking for a more technical answer I would say that stimulation of the Vagus is thought to cause alteration of norepinephrine (a neurotransmitter) release by projections of solitary tract (a part of the brain the vagus nerve is wired up to) to the locus coeruleus (A switching station in the brain).

Another theory is that the stimulation causes elevated levels of inhibitory GABA (another neurotransmitter) will cause inhibition of aberrant cortical activity by reticular system activation (a part of the brain which keeps us awake, but also seems to causes seizures in some people).

You may have noticed how I keep saying things like "thought to" and "theory"... That's because the exact mechanism of how VNS works is still not perfectly understood. There is a huge amount of evidence that IT DOES WORK. But to be completely honest.. we don't know the ins and outs of WHY.. I don't think we really will until we understand the ins and outs of Seizures completely and also the Brain for that matter.

But I've done this procedure before. i know it works on the majority of patients we select for it. But that's the thing, we have to select them well. Your neurologist and neurosurgeon have to work together on that one.

Now there are side effects, as you seem to be aware of already. The ones I want you to be damn sure you know about are.

1) Cardiac arrhythmia... this nerve also supplies the heart.. sometime we have to take the stim out because of this side effect.

2) Sleep Apnea: Intermittent decrease in respiratory flow during sleep has consistently been demonstrated in patients with VNS implants. Again, it has to do with the fact that the Vagus nerve controls the pathways that regulate this system.

3) You already mentioned the recurrent laryngeal nerve issues and so on so i won;t belabor this.

Now, these side effects don't necessarily HAVE to happen in everyone and even if they do, there are ways to mitigate them. getting an implant like this is a process.. not a one time event. So I want you to realize that until things settle down you will be in and out of the hospital getting the thing checked and tweaked for many many months.

Pain is not an issue i have come across except for the surgical implantation pain.. that can be handled with short term narcotics or other pain killers and generally drops to acceptable levels within a week or two and disappears in the weeks after that.

I wish I could tell you that this is an established procedure with 100 years of history behind it.. but it's not. So do we know everything there is to know about what will happen for you.. NO! You need to find a doctor you can put your trust in and work with them to see this through.

I hope this information helps. I hope things work out well for you. You can always come back and let me know whats going on if you want and I will help walk you through it. Feel free to follow up anytime. Take Care

Vinay

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