An end effector includes first and second jaws, first and second buttresses, and an ultrasonic blade. The first jaw includes a fastener cartridge having a first tissue contacting surface and a plurality of fasteners arranged in rows parallel to a longitudinal axis of the first jaw. The first buttress is attached to the first tissue contacting surface and the second buttress is attached to a second tissue contracting surface of the second jaw. The first and second jaws are movable relative to one another and are configured to grasp tissue therebetween. The ultrasonic is activatable to weld the first buttress to the second buttress and to subsequently cut the welded first and second buttresses and tissue grasped between the first and second jaws.
