Apparatus and methods are provided comprising an implantable non-hydraulic
ring that encircles and provides a controllable degree of constriction to
an organ or duct and an external control that powers and controls
operation of the ring. The ring includes a rigid dorsal periphery that
maintains a constant exterior diameter, and a compliant constriction
system that reduces intolerance phenomena. A high precision, energy
efficient mechanical actuator is employed that is telemetrically powered
and controlled, and maintains the ring at a selected diameter when the
device is unpowered, even for extended periods. The actuator provides a
reversible degree of constriction of the organ or duct, which is readily
ascertainable without the need for radiographic imaging. Methods of use
and implantation also are provided.
