The invention relates to a device for delicate treatment within a closed chamber, comprising a chamber connected to the closed chamber by means of a duct. The housing contains a piston, driven by a motor, with a layout permitting contact with an external fluid reservoir when said piston is in a certain position within the chamber such as to generate a sudden release of pressure. The device comprises an outlet valve which remains closed when the piston increases the volume of the chamber such as to generate the drop in pressure within the chambers.