You can make combat maneuvers with spells.
Prerequisite: Base attack bonus +6.
Benefit: Only spells that require an attack roll may be cast as combat spells. A combat spell does not use its normal attack roll, instead making a special combat maneuver check against target’s CMD. You use a bonus equal to your caster level plus your Intelligence, Wisdom, or Charisma modifier (whichever is highest). If you hit the target’s CMD, in addition to the spell’s normal effect you can affect the target with a bull rush, disarm, sunder or trip.
Even if you miss, the target cannot attempt to make a combat maneuver against you for your failed attempt.
A combat spell uses up a spell slot two levels higher than the spell’s actual level.
The Genius Guide To: Feats of Metamagic