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Digestive Diseases

Implanted neurostimulator palliates drug-refractory nausea associated with gastroparesis

08/01/2008


© Medtronic 2008
Patients who suffer from refractory gastroparesis often experience persistent nausea and vomiting that does not respond to medications. An implantable device that delivers mild electrical pulses that can reduce these symptoms is available through a humanitarian device exemption from the Food and Drug Administration.

Gastroparesis is a digestive disorder in which food moves through the stomach more slowly than is normal. Diabetes, certain autoimmune disorders and viral infections are known causes of gastroparesis, but in some cases the etiology is never known. Regardless of the cause, the delay in gastric emptying and the resultant nausea and vomiting can lead to unwanted weight loss and malnutrition, and can make it difficult for diabetic patients to maintain normal blood sugar levels.

The implantable device does not treat the delayed stomach emptying, but improves the patient’s symptoms and helps restore appetite. Even when the treatment is successful in palliating symptoms — the device can reduce the number of episodes from dozens per week to only a handful — patients should expect some breakthrough episodes of nausea and vomiting, for which they should seek medical management. This procedure is not a cure for gastroparesis.

Patient selection

Use of this implantable neurostimulator is approved for the treatment of chronic, refractory nausea and vomiting due to gastroparesis not responsive to appropriate diet and/or medical therapy. The key medical advantage of the procedure is that, with the decrease in vomiting, the device improves the reliability of medications reaching the small intestine for absorption. Additional benefits in controlling other gastroparesis symptoms, such as fullness, pain and easy satiety, have not been documented.

Patients with more generalized motility disorders of the gastrointestinal tract, such as chronic pseudo-obstruction syndrome or collagen vascular diseases such as scleroderma should not be considered for this procedure. Patients who have had a prior gastric surgery are also not candidates.

Surgical procedure

The procedure is performed with the patient under general anesthesia and usually takes about two hours. The implantable device consists of a small, programmable neurostimulator and a pair of connecting wires whose ends are placed in the stomach wall muscle. The neurostimulator is implanted under the skin outside the abdominal cavity and is carefully placed to hinder the patient’s movement as little as possible.

UCLA surgeons usually perform the procedure laparoscopically, though the procedure can be converted to an open one if the surgeon encounters reason to do so at the time of the surgery. The small incision size of the laparoscopic procedure promotes rapid recovery.

The risks of the implant include the usual risks inherent to all gastrointestinal surgeries and those associated with the use of anesthesia. Surgical complications can include:

  • erosion of the wires into the stomach, which requires a re-operation to reposition the wires
  • rare cases of bowel obstruction around the wires
  • infection at the site of neurostimulator implant

After the surgery

Following the implantation procedure, physicians use a wireless, handheld controller to program the implanted neurostimulator, adjusting the settings to achieve the best possible control of symptoms. The neurostimulator can also be activated and deactivated with the wireless controller. The outcome of the device implantation may not become apparent for the first six months following surgery, and the setting of the neurostimulator may need to be adjusted over the first year.

Though its exact mechanism is unknown, the device provides most gastroparesis patients with persistent nausea and vomiting relief from their symptoms. Patients eat more regularly and achieve better control of their blood sugar levels.

Device helps control nausea, leads to better nutrition

The implantable neuro-stimulator is used to control the symptoms of nausea and vomiting that can result from the delayed stomach emptying characteristic of gastroparesis. While it can be effective in palliating these symptoms, the device does not treat the underlying condition. “This procedure can be very beneficial — especially for diabetic patients. It is successful in roughly 80 percent of patients about 80 percent of the time. But it is not a cure and patients will have breakthrough symptoms,” explains Darryl T. Hiyama, M.D., F.A.C.S., professor of surgery at UCLA.

When successful, the treatment can significantly improve patients’ appetites and their ability to continue a regular diet. “Patients are able to eat better. The symptom palliation does lead to improved nutritional outcomes and better control of blood sugar for diabetics,” claims Dr. Hiyama.

Participating Physicians
Darryl T. Hiyama, M.D., FACS
Professor of Surgery
Division of General Surgery

Mark Ovsiowitz, M.D.
Assistant Professor of Medicine
Division of Digestive Diseases/Gastroenterology

Bennett Roth, M.D.
Clinical Professor
Division of Digestive Diseases/Gastroenterology

Contact information
Most insurance plans cover the cost of this procedure, though approval may take longer than usual because of the humanitarian device exemption. The exemption requires that the procedure be approved by the hospital’s Institutional Review Board (IRB), which UCLA has already done.
Call for appointments at (310) 825-1597. Fax (310) 794-9718
http://gastro.ucla.edu





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