Todd Wood, M.D., general surgeon at Memorial Hermann Southwest Hospital in Houston, Texas, explains how an implanted stimulator helps treat chronic nausea and vomiting in patients with a stomach condition that is often a complication of diabetes.
Who is a candidate for this device?
Dr. Todd Wood: A stimulator can help those with diabetic or idiopathic gastroparesis.
These are patients that have a significant dysfunction of the stomach, resulting in chronic nausea and vomiting, caused by either diabetes or by a cause we can't determine.
Is their stomach just not working the way it's supposed to?
Dr. Wood: It just doesn't work.
You eat food, the food sits in your stomach, and when your body gets tired of it sitting there, it tends to come back up, unfortunately.
Chronic intractable nausea and vomiting makes it difficult for these patients to work and maintain a life.
It's a major quality of life issue.
Before this stimulator, what could you offer these patients to treat their
Dr. Wood: There have been surgeries tried in the past with limited success.
The majority of the treatments have been medical, and the medications work in some patients, but not others.
Sometimes the medicines will work for some time until side effects develop.
By the time these patients get to the point where a stimulator would be
appropriate, they are at the end of their rope.
At this point isn't much more that medical science could do for them.
How does this stimulator work?
Dr. Wood: The mechanism of action with the stimulator are believed to be both central and local.
It is believed that stimulating vagal afferents of the stomach helps to disrupt some of the nausea/vomitng signals to the central nervous system.
On the local side, through direct stimulation of the nerves and muscles of the stomach, rhythmicity is being restored to the pacemaker of the stomach which helps with functional emptying.
How do you treat the symptoms in these patients?
Dr. Wood: In general, by the time they come to see me, they've exhausted all the medical treatments.
There really is not much more that medicine has come up with to
help them, so even though their stomach is not going to work much better, by suppressing the nausea,
it will work enough so that they can continue to keep food down.
They can avoid malnutrition and dehydration, and they can get on with their lives.
Is the surgery a non-invasive procedure or is it an open surgery?
Dr. Wood: We actually can do it both ways.
It can be placed either laparoscopically or through a small incision in the middle of the abdomen.
The open versus laparoscopic decision will be based on surgeon and patient preference.
Either way, you end up with about a two inch incision on the right side of the abdomen, were we place the generator.
The generator is then connected to two small wires that we implant on the wall of the stomach.
The generator sends electrical signals down the wires to stimulate the
stomach, resulting in the suppression of the nausea.
What does this mean for these patients?
Dr. Wood: It means a total change in their life. Most of these people, when they come to see me, are at wits' end.
They spend a significant amount of time in the hospital.
It's not uncommon to have one or two hospital admissions per month, and sometimes, they can spend up to 100 to 200 days out of a year in the hospital.
This makes it very difficult for them to work, for them to get out of the house, and for them to go on with their lives.
If the stimulator works for them, then they can get back to their lives, they can more easily maintain a job, and it gives them their life back.
In published, placebo-controlled, randomized study called the WAVESS study in Gastroenterology 2003, we saw roughly 80 percent of patients get a greater than 50 percent reduction in weekly episodes of nausea and vomiting at one year post-implant and significant improvement in gastric emptying at one year.
What causes these stomach problems?
Dr. Wood: Now that we are better looking for gastroparesis, we're starting to identify it more frequently.
In the past, gastroparesis has been under-diagnosed.
In milder cases patients will feel nausea every once in awhile so for the most part they can live their life with only mild inconvenience.
For patients with severe gastroparesis, with severe and
intractable nausea and vomiting, medical therapy cannot help.
For these patients the stimulator can help decrease nausea and vomiting from a diabetic or idiopathic cause.
Once you implant the stimulator, does it stay there for the rest of their life?
Dr. Wood: Generally speaking, yes.
The generator has a battery life of about seven years so it will need to be changed periodically.
I would imagine that the patients are not going to be willing to let you remove it.
Has the FDA approved the stimulator?
Dr. Wood: It has been approved by the FDA as a humanitarian-use device in that we know it can help some patients when nothing else works.
The stimulator is not a cure, but can help give the patients back their lives.