A laparoscopic scissor instrument can include a scissor assembly pivotally coupled to an elongate shaft. The scissor assembly can be formed of scissor blades having apertures. A rivet or pivot pin can couple the scissor blades to the elongate shaft. The scissor blades can also include actuation posts thereon. An actuation mechanism slidable within the elongate shaft can include a slot to engage the actuation posts and open or close the blades of the scissor assembly. The elongate shaft can include a longitudinal guide to stabilize the motion of the actuation mechanism. The actuation mechanism can have a forked end including projections to flexibly maintain the spacing of the forked end.