[Ultrasonic skull trepanation].

Experimental ultrasonic cranial trepanation was performed on 60 albino rats by means of a semi-automatic device, Y3T-1. The trepanation is altraumatic and does not need any considerable physical effort. A histological examination showed that the zone of bone necrosis along the edge of the cut surface was one third to one half that developing with the use of electric and pneumatic surgical instruments.