An injection port and implantable pump for adding fluid to, or withdrawing fluid from, a surgical implant inside a patient's body is disclosed. Also disclosed is a surgical method for treating diseases using the injection port and pump. The injection port and implantable pump includes a rigid base member and an injection membrane penetrable by an injection needle and attached to the base member. The membrane and base member define a chamber for holding fluid. The membrane is displaceable relative to the base member between a first position in which the volume of the fluid chamber is maximal and a second position, in which the volume of the chamber is minimal. According to the method, the membrane is manually displaced from time to time to distribute fluid between the fluid chamber of the injection port and the implant to operate the implant, which is typically a hydraulic restriction device. The implant can be designed for treating reflux disease, urinary incontinence, impotence, anal incontinence or obesity.
