Ultrasonic horn, ultrasonic transducer assembly, and ultrasonic surgical instrument including the same

An ultrasonic transducer assembly of an ultrasonic surgical instrument, comprising:

• a piezoelectric stack defining an outer diameter;
• an ultrasonic horn secured to and extending distally from the piezoelectric stack, the ultrasonic horn including a body and a nose extending distally from the body, the body defining a length, a longitudinal axis extending along the length of the body and a maximum diameter of the ultrasonic horn, the body including a depression formed circumferentially and continuously around the body, the depression including at least one substantially flat portion configured to prevent rotation of the body, the at least one substantially flat portion facing out of the depression along a direction substantially perpendicular to the longitudinal axis of the body;
• and
• an enclosure surrounding the piezoelectric stack and a portion of the ultrasonic horn, the enclosure including at least one protrusion extending inwardly therefrom, the at least one protrusion configured for receipt within the depression of the body to secure the ultrasonic horn within the enclosure,
• wherein an outer surface of the body extends along the maximum diameter of the ultrasonic horn, and
• wherein an uppermost extent of the depression is substantially aligned with the outer surface of the body along the maximum diameter of the ultrasonic horn.

An ultrasonic surgical instrument, comprising:

• a handle assembly, including:
• a housing;
• an ultrasonic transducer assembly supported by the housing, the ultrasonic transducer assembly including:
• a piezoelectric stack defining an outer diameter;
• an ultrasonic horn secured to and extending distally from the piezoelectric stack, the ultrasonic horn including a body and a nose extending distally from the body, the body defining a length, a longitudinal axis extending along the length of the body and a maximum diameter of the ultrasonic horn, the body including a depression formed circumferentially and continuously around the body, the depression including at least one substantially flat portion configured to prevent rotation of the body, the at least one substantially flat portion facing out of the depression along a direction substantially perpendicular to the longitudinal axis of the body,
• wherein an outer surface of the body extends along the maximum diameter of the ultrasonic horn, and
• wherein an uppermost extent of the depression is substantially aligned with the outer surface of the body along the maximum diameter of the ultrasonic horn;
• and
• an enclosure surrounding the piezoelectric stack and a portion of the ultrasonic horn, the enclosure including at least one protrusion extending inwardly therefrom, the at least one protrusion configured for receipt within the depression of the body to secure the ultrasonic horn within the enclosure;
• and
• an elongated assembly extending distally from the handle assembly, the elongated assembly including a waveguide configured to engage the nose of the ultrasonic horn, the waveguide defining a blade at a distal end thereof,
• wherein ultrasonic energy produced by the piezoelectric stack is transmitted along the horn and the waveguide to the blade for treating tissue adjacent the blade.