Electronic Design

The Telemetric Way To Weight Loss

Forget about painful and messy saline solution injections. The EasyBand system uses RF signals to adjust gastric bands and regulate weight loss.

Severe obesity is a major health issue in the Western world, particularly in the U.S. In addition to diet and exercise, the use of laproscopic surgically implanted bariatric bands has experienced a surge in popularity over the last few years. In fact, it's gaining more favor over other drastic stomach bypass procedures. According to the Millennium Research Group, the laproscopic bariatric device market, which includes gastric bands and devices like extended-length hand instruments, is growing. It will reach over $200 million in the U.S. and grow at an annual rate of more than 20% for the next five years.

Nearly all of the current products on the market use adjustable bands filled with an opaque isotonic or saline solution. Doctors place the band at the top of the stomach via laproscopic surgery (usually same-day surgery) to limit food intake (Fig. 1). These bands require an access port where doctors can insert a needle to change the amount of fluid in the belt and periodically adjust the belt's tightness as the patient loses weight.

Yet this port-access method has led to some major complications. Patients have had to endure infections, port-site pain and discomfort, fluid leakage, fluoroscopy for port access, belt migration and erosion, and port-site revision. The EasyBand, though, promises to eliminate these problems.

Developed by Swiss company Endoart, the system uses telemetry signals to adjust the band. The 27-MHz RF signal is based on the company's Flowatch telemetering technology. No battery is required since a remote unit powers, programs, and controls the EasyBand. Band adjustments are enabled by a small internal electric motor.

Measuring just 3 mm thick, the device consists of an antenna, a band, a clip, a sleeve, and a cable (Fig. 2). The antenna is implanted subcutaneously in the body in an 18-mm trocar, which is an instrument passed through the body to allow for the easy exchange of endoscopic instruments during surgery. Adjustments can be made in 0.1-mm increments over a range of 20 to 29 mm.

Physicians can use the handheld control box, which measures 200 by 100 by 65 mm and weighs 750 g without accessories, to adjust the belt (Fig. 3). A 16-bit microcontroller with an MC16 core from Renesas Technology lies at the heart of the control box. The control unit contains 256 kbytes of flash program memory and 20 kbytes of RAM.

Magnetic inductive coupling is used between two antenna loops—one antenna located in the body and the other on the outside. The external antenna, connected to the control unit, transmits commands to and receives information from the implanted antenna connected to the EasyBand gastric belt. The external antenna features a 6-cm diameter inductive loop with a 2-m connection cable and an easylock connector.

A weak electromagnetic field is set up between the two antennas, inducing the electric power needed for band adjustment and information transmission. The magnetic field is 10,000 mV/m when measured at a distance of 3 m, which corresponds to a level of 25 dBmA/m, conforming to the limits set by the U.S. Food and Drug Administration.

EasyBand has been approved for use in Europe since 2005 and has undergone field trials in the U.S. since last year. According to Endoart, it may be a few more years before the FDA approves its use. The company, though, is bullish on getting this approval judging from the positive results it already has obtained from the field trials, both in the U.S. and in Europe.

Two European centers performed detailed performance studies comparing the RF-controlled EasyBand and the fluid-based LapBand, another widely used gastric band. The studies revealed that the EasyBand performs favorably with the LapBand in terms of the percentage of weight loss (Fig. 4).

"Endoart's technology offers significantly higher comfort to patients. Remote adjustment allows precise and painless control of the device, which is key for patient compliance and success of treatment," says Philippe Dro, chairman and CEO of Endoart. "With severe obesity a mounting global concern, Endoart is excited to offer a device to surgeons that helps patients realize their weight loss goals and achieve a healthier quality of life."

A COMPETITIVE FIELD
The EasyBand will face stiff competition from a number of companies using FDA-approved gastric bands in the U.S., the most prominent being the LapBand from Inamed Health (now owned by Botox maker Allergan). MID Medical Innovation Development also supplies the MID Band.

Obtech Medical, now Ethicon and part of Johnson and Johnson, offers the SAGB—Swedish Adjustable Gastric Band. Intrapace provides a different kind of gastric band that keeps pulsing around the stomach, giving patients the illusion that they're sated and full. This device, which is inserted via the throat, is in trials.

Endoart
www.endoart.com

TAGS: Components
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