Abstract: Gastric restriction device implants and their use in controlling body weight are described. In some embodiments, activation of a shape memory material drives an actuator coupled to an implant, resulting in a conformational change in the implant. In some embodiments latch and ratchet mechanisms operate incrementally to increase or decrease a size of a stomal opening produced by the gastric restriction device. Methods are described by which adjusting the size of the stomal opening is used to restrict the rate at which food passes through the stomach.

Abstract: Implants for treatment of obesity may be placed within the stomach and/or esophagus or around the outside surface of the stomach and/or esophagus. The implants comprise at least a portion constructed of a shape memory material. The implants are thus adapted to be implanted in a deformed shape, and then to be transformed through the application of activation energy into a memorized shape. The shape and/or size transformation induces a change in shape of the stomach and/or esophagus, thus altering the normal digestive path of food entering the patient's gastrointestinal tract.