Internal Gastric stimulator or gastric pacing

back to Obesitysurgery-info.com       V-Bloc... gastric pacing with a couple of improvements

In 2003 when large numbers of gastric bypasses were being done and consequently, a high incidence of complications were being observed, a much higher complication rate than formerly thought, the IGS, a pacemaker like device seemed to hold great hope for obesity surgery.

Pacemakers for the stomach are not new.  They have been used for a condition known as gastroparesis (stomach does not empty) for at least a few years with a modicum of success (apparently not enough to make it the standard treatment however).  And of course we are all familiar with heart pacemakers.

The IGS procedure was invented by Dr Valerio Cigaina, a Italian surgeon and his first patient was his secretary who had about 40 lbs to lose and did it successfully, he claims with the IGS. Her smiling face was one often seen in the promos for this device.

Unfortunately after many unsuccessful trials in the USA, the hope for the IGS has somewhat died.  Americans CAN go to Europe to get one but it's expensive ($50,000) and follow up might be difficult to obtain in the USA.

What the IGS was supposed to do is stimulate the nerves of the stomach to prevent or slow the stomach from emptying after eating, causing patients feel "full" for longer and thus eat less.

The great advantage of it was the no "messing" with the digestive system at all (i.e. no stomach stapling or rearrangment of the bowels or even banding) which sounded good after more and more gastric bypass horror stories emerged (and even some not so nice stories about the adjustable lap band which is the safest obesity surgery available at present).

Trouble is, the IGS does NOT work for most people.  In the trials the average weight loss was 10-25 lbs, some did not lose any weight at all and only a very few, about 3 patients lost a significant amount of weight (and one of the significant weight losers lost weight by becoming ill with cancer and complications of the IGS).  Most of the patients in the trials converted to other procedures to lose their weight.

The poor track record in weight loss is not the only problem with the IGS.  There are several repercussions which can make the patients very uncomfortable.  For one, it can cause a medically induced case of GERD, causing patients to suffer heartburn, and acid reflux (which if happens at night and it gets into the lungs, it not only can really HURT but can in the most severe cases, cause a type of pneumonia).  It also raised the risk for Barrett's esophagus.

Like pacemaker patients, IGS patients must follow certain restrictions with MRIs and scans (i.e. have the pacer turned off before they have any type of radiographic testing done).

The pacemaker used in the IGS carries the same risks as the heart pacemaker, some of which are

  • Inflammation in the tissues surrounding the pacemaker
  • the pacemaker traveling to other parts of the body - this actually happens more with the IGS than the heart pacemaker because of where the IGS is placed

No one likes to even mention this but of course, anything with a battery runs a small risk of battery related problems i.e. leakage etc.  These are very rare but can, I suspect, be nasty when they happen.

There are some additional issues with the IGS which do NOT exist with the heart pacemaker. The electrical current generated by the IGS is significantly greater than that provided by a heart pacemaker i.e. 10 times the intensity or more.  Besides sometimes causing the patient discomfort when the pacer is stimulating, (patients complained of numbing or strange feelings in their arms), this also means that the IGS burns batteries a lot faster than heart pacemakers do.  IGS batteries need to be replaced every 9-12 months - this requires a small surgery.

Also patients and providers complained that the IGS was much more difficult to program than the heart pacemaker (it's programmed with a device which which lies on top of the skin).  If it was programmed to release too little current, it had no effect on the patient but programming it to release a lot of current caused discomfort in other areas when the IGS was stimulating the stomach.  The happy medium apparently was never reached in many patients.

Surgeons were warned in the instructions for doing the surgery, that the leads must be placed very carefully or else, perforation of the stomach can occur. They also were told to immediately scope for gastric perforation after placing each lead.

The companies manufacturing the IGS components tried hard to create a public need by media spin, but the ongoing poor results in the trials caused the media to greatly lose interest in the device.  Most of the WLS surgeons who were involved in the trials, lost interest as well, except for one who runs most of the trials going on now and gets many customers for gastric bypass and adjustable lap band from dissatisfied IGS patients.

Media coverage of the trials portrayed them as promising:

The first gastric stimulator for the treatment of morbid obesity was implanted by Dr. Valerio Cigaina in 1995. That patient lost 80% of her excess weight over the first 21 months of treatment. A second study was initiated by Cigaina in 1998, involving 10 patients who received Transneuronix’ first-generation Prelude® IGS. The 1998 patient group has lost a mean of 25% of its excess weight at nearly three years after initiation of gastric stimulation as shown in the graphic below.

Food intake was reduced due to an early and increased satiety reported by the patients. In conclusion, long-term studies continue to show that gastric pacing can be a safe and effective procedure to treat morbid obesity.

Here is a study which appeared in Obesity Surgery Journal in April of 2002 - the inventor of the IGS was the author of this article.  Last I heard he was still offering them in his practice in Switzerland for $50,000 per patient placement:

Gastric pacing as therapy for morbid obesity: preliminary results.
Cigaina V
Obes Surg 2002 Apr 12 Suppl 1:12S-16S

Abstract
BACKGROUND: A novel method to treat morbid obesity is presented--gastric electrical pacing. Following animal research, human investigation in a total of 24 patients in three cohorts began in 1995. METHODS: Morbidly obese subjects (BMI > or = 40) received electrical stimulation devices in 1995/6 (n = 4), 1998 (n = 10) and 2000 (n = 10). Electrodes were positioned intramuscularly on the anterior gastric wall at the lesser curvature. BMI = body mass index; %EBL = % excess BMI (> 25) lost. RESULTS: Patients reported satiety for food with less food. The 2 patients from the first study followed for > 5 years have achieved 38 and 67 %EBL. In the second study, every patient lost weight. At 36 months follow-up, the mean %EBL was 24 +/- 10 SD (n = 10). CONCLUSIONS: Implantable gastric pacing is a safe procedure and causes changes in eating habits in morbidly obese humans, resulting in decreased food intake and weight loss.
 

Notice that the cohort reported on in these two articles, was very small and the follow up was less than 3 years.

Like so many other things, the reality is considerably less exciting than the promos were. 

According to the Medtronic site, no new trials are being started in the USA at present.  (The Transneuronix website is apparently down and "transneuronix.com" is being forwarded to Medtronic now). The Medtronic focus is on many other types of electronic devices although people can still obtain information on the IGS for obesity (which Medtronic calls the "GES"  or Gastric Electrical Stimulator)

http://www.medtronic.com/obesity/ 

Articles in peer reviewed journals about IGS/GES