Athough, technically, they can't really increase or decrease the the midface height which is the area between the root of the nose ('top' of it near the glabella) and the base of the nose, they can increase the facial height between root of nose and base of chin so you have more 'face space' to better distribute soft tissue. That's done with a 'down graft' put in during the lefort1. The distance increase is seen to the lower '1/3rd' of the face. The lefort 1 can also have other movements in order to accommodate what needs to be done to the lower jaw and also for the front teeth to show in the right place and for the back teeth to meet in the right place.