The present invention relates to method for implanting a medical device for controlling a flow of fluid in a lumen formed by a tissue wall of a patient's urethra. The method is performed by: cutting the skin of the patient, inserting a dissecting tool and dissecting an area of at least one portion of the tissue wall of the urethra, placing an adjustable constriction device in the dissected area in operative engagement with the urethra, placing an operation device configured to operate the adjustable constriction device to control the flow of urine in the urethra in the patient's body, placing a sensor configured to sense a temperature of the medical device in the patient's body, and placing a control unit in the patient's body configured to control the operation device based on information from the sensor.