Power-assisted obturator

A power-assisted obturator system for penetrating a body cavity wall is provided. The system comprises an obturator having main shank with a tip on its distal end. The tip has relatively blunt dull cutting edges which are incapable of readily cutting through bodily tissue except when the tip is vibrated at ultrasonic or near-ultrasonic frequencies. The proximal end of the main shank is connectable to an ultrasonic power source, which provides power to vibrate the obturator tip at ultrasonic or near-ultrasonic frequencies thereby transforming the relatively blunt edges into cutting edges which simultaneously cut and coagulate tissue. In a preferred embodiment, the obturator system includes vibration feedback and control which terminates delivery of energy to the tip when penetration is sensed.