A surgical apparatus includes a rotatable shaft and a turbine assembly. The rotatable shaft includes a cutter located thereon. The cutter is configured to cut an object when the shaft is rotating about a rotational axis. The turbine assembly includes a turbine and a turbine housing. The turbine housing is configured to receive a fluid that enters the housing parallel to the rotational axis, and to steer the fluid to impinge on the turbine in a direction that is not parallel to the rotational axis. The turbine is configured to rotate the shaft so as to cut the object by the cutter.