Abstract: Disclosed is a percutaneous access device (PAD) for long-term skin penetration and use as an access port in the body of a patient. The buttonlike device includes a flat skirt for subdermal anchoring of the PAD and a neck through which a tube may extend for transmission of materials to or from the body. A two-stage porous bed covering the skirt and at least a portion of the neck promotes formation of a tight, infection-free barrier between the percutaneous access device and adjacent tissues, stabilizing the device for long-term use. The first stage of the bed retards downgrowth of epidermal cells for a time sufficient for mature collagen to form in the second stage, thereby permitting the tight dermal/biomaterial interface or barrier to form at a location near the junction of the two stages.