A detection method of a slow leak in a hydraulic occlusive system implantable in an animal or human body to occlude a natural conduit. The system includes a hydraulic circuit with an inflatable occlusive cuff containing a variable volume of fluid, surrounding a part of the natural conduit, a reservoir containing fluid, and a fluidic connection between the cuff and the reservoir. An activation device is coupled to a mobile element of the hydraulic circuit to transfer a determined volume of fluid from the reservoir to the cuff or from the cuff to the reservoir. A control unit urges the activation device to exert determined compression on the conduit. A variation of the compression exerted by the cuff on the conduit is created by transfer of an adjustable volume of said fluid between the reservoir and the cuff by measuring the evolution of the pressure in the hydraulic circuit.
