Devices for attaching a sheet-like implant to a target tissue include a sheath and a staple push rod. The sheath has a distal end configured to be pressed against the target tissue. The staple push rod is disposed within at least a portion of the sheath and is slidable relative thereto. The staple push rod includes a pair of stakes. Each stake is dimensioned to abut a surface of a staple to apply pushing forces thereto. The stakes are biased to assume a bow-like shape such that an intermediate portion of a staple extends tautly between the first stake and the second stake when the stakes are extending beyond the distal end of the tubular member. Methods for attaching a sheet-like implant to a target tissue are also disclosed.