An ultrasonic surgical instrument includes at least two tools each having a respective operating head with an operative surface or edge. At least one source of ultrasonic mechanical vibratory energy is provided which produces at least two vibration modes out of phase with one another. The tools are each connected to the source of ultrasonic mechanical vibratory energy for enabling transmission of a respective one of the vibration modes into the respective tool so that the tools are driven out of phase with one another.
