Tissue cushion adjunct with staple leg support features for surgical stapler end effector

A surgical instrument includes an end effector including a first jaw having a plurality of pockets and a second jaw. The first and second jaws are operable to clamp tissue therebetween. The surgical instrument also includes a stapling assembly supported by the second jaw of the end effector. The stapling assembly includes a deck, a plurality of staple openings extending through the deck, and a plurality of staples slidably housed within corresponding staple openings. Each staple has a respective pair of legs configured to be driven into contact with a corresponding pocket. The surgical instrument further includes a plurality of staple leg constraints. Each staple leg constraint is aligned with and extends at least partially across a corresponding staple opening for guiding a respective leg of the corresponding staple toward the corresponding pocket.