A surgical instrument includes an end effector having a clevis and first and second jaws mutually rotatable between open and closed positions. The jaws are proximally directed and laterally displaced relative to a longitudinal axis of a control shaft of the instrument. The jaws hold first and second parts of a fastener, respectively. The first part includes a base having upstanding tissue piercing posts, and the second part includes another base defining apertures for receiving the posts, as well as a portion movable relative to the second base. When the upstanding posts are inserted into the apertures, the movable portion can be moved into a second configuration to lock the parts of the fastener together. The instrument is adapted to move the second part into the second configuration. A method for using the apparatus and fastener are also provided.