Staggering Strike

 
Prerequisite(s): Sneak Attack, Base Attack Bonus 6+
 
Benefit: If you deal damage with a melee sneak attack, you can also deliver a wound that limits your foe’s mobility. For 1 round (or until the target is the beneficiary of a DC15 heal check or magical healing), your target is treated as if it were staggered. This effect can be resisted by a Fortitude save vs DC= Damage Dealt. This feat has no effect on creatures immune to sneak attack.
 
Source: Complete Adventurer