A surgical implant includes an inflatable element that is inflatable responsive to fluid pressure; a tank for fluid under pressure in communication with the inflatable element to regulate the pressure of the element; a manually controlled pump in communication firstly with the inflatable element via a one-way check valve, and secondly with the tank via a one-way check valve; and a control unit incorporating the tank and the manual pump. The control unit presents a through opening for the fluid, the opening being in communication firstly on the inside of the control unit with the tank and the manual pump, and secondly on the outside of the control unit solely with the inflatable elements via a catheter mounted between the inflatable element and the control unit. The tank is formed by a leaktight chamber of fluid under pressure defined by a movable piston elastically biased by a spring.