The present disclosure relates to an anvil assembly, an end effector and/or a surgical stapler suitable for performing curved or circular anastomosis and/or treatment to internal walls of hollow tissue organs wherein the anvil assembly includes an anvil center rod having a proximal end and a distal end, the center rod defining a central longitudinal axis; and an anvil head secured to the distal end of the anvil center rod. The anvil head includes an anvil plate defining a tissue contact surface; and a plurality of staple forming pockets formed in the tissue contact surface of the anvil plate, wherein each of the plurality of staple pockets defines an arcuate longitudinal axis.