| WEIgHTMAnAgEMEnT | OpiniOn
making adjustment easier. The product is CE‑marked, but is not yet approved in the US. Alternative gastric banding systems
include the Midband, manufactured by the French company Médical Innovation Développement; the Bioring, marketed by French firm Cousin Biotech; the MiniMizer Extra, from the Swiss company Bariatric Solutions; and the Heliogast gastric band, which is made by another French firm, Hélioscopie.
Other approaches However, reducing the size of the stomach, or the rate at which food can flow through the digestive tract, is not the only approach to the management of obesity. Some companies, such as the Israeli firm MetaCure, have turned to electrical stimulation as a way of controlling eating habits. MetaCure’s product for the treatment of
obesity, as well as type 2 diabetes, is the Diamond (Tantalus) System, an implantable device that applies automatic electrical gastric stimulation during meal times. The natural activity of the stomach is monitored in real time via sensing electrodes, and non‑excitatory electrical stimulation applied during meals to induce a feeling of satiety. The Tantalus System, which is
CE‑marked in Europe, but not yet approved in the US, comprises a rechargeable,
pacemaker‑like
implantable pulse generator with an external, portable charger, three leads, and external control and monitoring components for the patient and physician. The pulse generator and the leads are implanted laparoscopically during an outpatient procedure. Just approved in Australia and already
available in Chile, germany, the UK and the netherlands (but not in the US) is gI Dynamics’ EndoBarrier gastrointestinal Liner System, which is indicated for 6 months’ use in the treatment of type 2
diabetes and obesity. The EndoBarrier Liner is placed in the small intestine via the transoral route in a brief endoscopic procedure. When in place, it lines the small intestine from just below the pylorus for a distance of approximately 60 cm, creating a physical barrier that prevents food from coming into contact with the intestinal wall. In this regard it achieves the same effect as a Roux‑en‑Y procedure, but without the need for surgery. The presence of the liner appears to alter the activation of hormonal signals that originate in the intestine.
Continuing development In addition to the above, a number of products are still in development. These tend to fall into two categories: those that act via electrical stimulation of the stomach, and those that are designed to reduce the capacity of the stomach. Among the latter is Satiety’s Toga System. With the patient under general anaesthesia, the Toga Sleeve Stapler is inserted through the mouth into the stomach. The stomach tissue is spread and positioned using a retraction device, and suction is used to collect tissue from the anterior and posterior regions of the stomach. The device is then closed, and titanium staples are delivered to create a sleeve at the entry of the stomach. next, the Toga Restrictor is inserted to narrow the bottom of the sleeve. The resulting pouch collects food as it enters the stomach, giving patients a feeling of fullness after a small meal. Satiety, which was founded in 2000
and is located in Palo Alto, California, is currently carrying out a multi‑centre US evaluation of the Toga System. Experimental devices that act via
electrical stimulation of the stomach include IntraPace’s abiliti system, which is implanted laparoscopically, and Silhouette Medical’s nObese device, which is placed in the stomach via the mouth and oesophagus. The abiliti system is designed to detect
when the patient consumes food or drink. When this happens, it delivers a series of low‑energy electrical impulses to the stomach to create a feeling of fullness. During insertion of the system, a lead is attached to the stomach — one end carries the sensor, while the other end attaches to the gastric stimulator, which is implanted under the skin. A couple of weeks after insertion, the device is activated and
programmed to the needs of the individual patient. The system can also record the activity of the stomach in order to provide a picture of food consumption that can be used in patient education. IntraPace was founded in 2001. The
abiliti system is currently undergoing clinical trials in Europe. Silhouette Medical’s nObese device, in
contrast, is inserted transorally. Once in place, it is strategically positioned so that treatment effects can be controlled and targeted to specific areas within the stomach. For example, it can be used to ‘switch off’ those parts of the stomach that produce ghrelin. EnteroMedics, a St Paul, Minnesota
company, is developing its Maestro system, which acts via neuromodulation of the vagus nerve (VBLOC therapy). The vagus regulates much of the activity of the stomach and the pancreas, and is also thought to play a role in the signalling of satiety and hunger. The company is evaluating the system in the US, Australia, Mexico, norway and Switzerland. Preliminary results from the pivotal EMPOWER trial3
showed that use of the
device was associated with clinically meaningful weight loss, although the primary and secondary endpoints were not met. The company is currently carrying out a pivotal trial (the RECHARgE trial4 second‑generation rechargeable device.
) of a
Conclusions Despite the apparent reluctance of some healthcare providers to consider bariatric surgery, the epidemic of obesity means that the demand for new and improved devices to control calorie intake is set to grow. The only question is, will there be enough trained surgeons to use them?
References
1. Unhealthy diets and physical inactivity. World Health Organization. Geneva: 2009. http://tinyurl. com/3tb8g2x (accessed 1August 2011)
2. Buchwald H, Oien D. Metabolic/bariatric surgery Worldwide 2008. Obes Surg 2009; 19(12): 1605–11
3. EMPOWER Clinical Trial: Vagal Blocking for Obesity Control. National Institutes of Health. US: 2008.
http://tinyurl.com/3w9zux9 (accessed 1August 2011)
4. The RECHARGE Low Carbohydrate Diet Trial for Metastatic Cancer. National Institutes for Health. US: 2010.
http://tinyurl.com/3sx4yyw (accessed 2August 2011)
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