The forceps instrument includes a central pull-push member formed by gearing and actuating elements. The central push-pull member opens and closes the branches, and also acts as a tissue abutment that is variable based on the degree of closure of the branches. The variable tissue abutment may be configured as a slider element and is adjustable proportionally to the opening angle of the branches. When grasped, the vessels are brought proximally. The tissue abutment acts as a spacer between the hinge region and the grasped material. While the branches are being closed, the vessel is held stationary and compressed. During compression, expansion of the vessel occurs axially in distal and proximal directions. Due to the receding of the variable tissue abutment during the closing operation, room is created for the grasped material to escape. Tissue accumulations can thus be restricted and overstressing of the tissue can be counteracted.
