Surgical tissue fusion instrument and support structure having two gripping structures which are movable relative to each other and which are designed to bring together biological tissue sections that are to be connected to each other, with heat-generating means which are assigned to the gripping structures and, during tissue fusion, cause heat to be introduced in the area of a connection site of the biological tissue sections, and also with a support structure which is held between the gripping structures and, during tissue fusion, is operatively connected to the tissue sections. The support structure has at least one additional physical functional structure for aiding or promoting the tissue fusion.