Wireless gastric stimulators

Gastric dysmotility disorders including gastroparesis cause chronic debilitating symptoms. Gastric electrical stimulation (GES) has shown to be effective in stomach pacing, gastric emptying and treating gastric dysrhythmia. However, the current battery-based GES devices are bulky yet with limited lifetime. The device implantation requires a major surgery. In this paper, we present miniature wireless gastric electrical stimulators to overcome the existing shortcomings. Rechargeable battery based and batteryless stimulators were tested in benchtop experiments and live porcine animal models. The battery-based system utilizes wireless charging while the batteryless device harvests electromagnetic energy to power a microcontroller that delivers electrical pulses to tissues. Both prototypes were tested at three different stimulation settings for demonstration. Recorded electrogastrograms (EGG) in stomach were analyzed in terms of signal amplitude, frequency, stimulation power and energy. EGG frequency variations, amplitude ratios, and gastric rhythmic activities during GES were analyzed. The results showed that the wireless miniature stimulators modified gastric rhythmic activities. Utilization of these miniature devices may eliminate the need of repeated surgeries for battery replacement. The small size of the stimulators also makes it feasible to implant them through endoscopic surgeries.