A fluid interface device for delivering fluid to and/or withdrawing fluid from a patient, the device comprises a peripheral base element (2) and a fluid transmission element (4) sealingly connected to the base element and forming a central portion of the device. The fluid transmission element comprises a front platelet (6) with a primary face (8) and a secondary face (10) opposed thereto, the primary face being in contact with a patient's body fluid region (12) when the device is implanted in the patient, the fluid transmission element further comprising a counterplate (14) sealingly stacked against the secondary face of the front platelet and forming a buffer volume (16) therebetween. The front platelet comprises at least one array of microchannels (18) defining a fluid passage between the buffer volume and the primary face, the microchannels having an opening of 0.2 to 10μηι. The counterplate has at least one fluid port (20; 20a, 20b) for fluid delivery to and/or fluid withdrawal from the buffer volume.