A method of joining together two tissue layers includes positioning a tissue anchor over a first tissue layer. The tissue anchor includes a plate having top and bottom surfaces, an array of first pins projecting from the bottom surface of the plate that oppose the first tissue layer, and an array of second pins projecting from the top surface of the plate that face away from the first tissue layer. A second tissue layer is placed over the first tissue layer and the tissue anchor so that the second pins oppose the second tissue layer. The second tissue layer is pressed onto the tissue anchor and toward the first tissue layer so that the first pins advance into the first tissue layer and the second pins advance into the second tissue layer for joining together the first and second tissue layers. The plate has second pin apertures and the second pins are free to slide and move independently of one another within the second pin apertures.
