Ultrasonic transducer assembly and ultrasonic surgical instrument incorporating the same

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

a piezoelectric stack;

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;

an overmold seal about the body of the ultrasonic horn; and

a casing disposed about the piezoelectric stack, the body of the ultrasonic horn, and the overmold seal, the casing defining a distal opening through which the nose of the ultrasonic horn extends, the overmold seal establishing a hermetic seal with the casing to define a hermetically sealed interior enclosing the piezoelectric stack and the body of the ultrasonic horn therein, wherein the casing is configured to be arranged in a housing of a surgical instrument, wherein the body of the ultrasonic horn defines at least one radially-facing recess, and wherein the overmold seal is arranged about and within the at least one radially-facing recess and includes at least one pass-through electrical connector extending therethrough.

2. The ultrasonic transducer assembly according to claim 1 , wherein the body of the ultrasonic horn includes first and second body portions joined to one another at a seam.

3. The ultrasonic transducer assembly according to claim 2 , wherein the first and second body portions are joined to one another at the seam via welding.

4. The ultrasonic transducer assembly according to claim 2 , wherein the seam is disposed near a node location along the ultrasonic horn.

5. The ultrasonic transducer assembly according to claim 2 , wherein the first and second body portions include complementary opposing faces to facilitate joining.

6. The ultrasonic transducer assembly according to claim 1 , wherein the body of the ultrasonic horn defines a plurality of radially-facing recesses.

7. The ultrasonic transducer assembly according to claim 1 , wherein the at least one radially-facing recess of the body of the ultrasonic horn is discontinuous.

8. The ultrasonic transducer assembly according to claim 1 , further comprising first and second electrode assemblies disposed within the hermetically sealed interior and associated with the piezoelectric stack, the first and second electrode assemblies electrically coupled to first and second pass-through electrical connectors of the at least one pass-through electrical connector.

9. The ultrasonic transducer assembly according to claim 1 , wherein the casing includes a plurality of casing components joined to one another at hermetically sealed seams.

10. An ultrasonic surgical instrument, comprising:

a handle assembly, including:

a housing; and

an ultrasonic transducer assembly supported by the housing, including:

a piezoelectric stack;

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;

an overmold seal about the body of the ultrasonic horn; and

a casing disposed about the piezoelectric stack, the body of the ultrasonic horn, and the overmold seal, the casing defining a distal opening through which the nose of the ultrasonic horn extends, the overmold seal establishing a hermetic seal with the casing to define a hermetically sealed interior enclosing the piezoelectric stack and the body of the ultrasonic horn therein, wherein the casing is arranged in the housing of the handle assembly, wherein the body of the ultrasonic horn defines at least one radially-facing recess, and wherein the overmold seal is arranged about and within the at least one radially-facing recess and includes at least one pass-through electrical connector extending therethrough; 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 ultrasonic horn and the waveguide to the blade for treating tissue adjacent the blade.

11. The ultrasonic surgical instrument according to claim 10 , wherein the body of the ultrasonic horn includes first and second body portions joined to one another at a seam.

12. The ultrasonic surgical instrument according to claim 11 , wherein the first and second body portions are joined to one another at the seam via welding.

13. The ultrasonic surgical instrument according to claim 11 , wherein the seam is disposed near a node location along the ultrasonic horn.

14. The ultrasonic surgical instrument according to claim 11 , wherein the first and second body portions include complementary opposing faces to facilitate joining.

15. The ultrasonic surgical instrument according to claim 10 , wherein the body of the ultrasonic horn defines a plurality of radially-facing recesses.

16. The ultrasonic surgical instrument according to claim 10 , wherein the at least one radially-facing recess of the body of the ultrasonic horn is discontinuous.

17. The ultrasonic surgical instrument according to claim 10 , further comprising first and second electrode assembles disposed within the hermetically sealed interior and associated with the piezoelectric stack, the first and second electrode assemblies electrically coupled to first and second pass-through electrical connectors of the at least one pass-through electrical connector.

18. The ultrasonic surgical instrument according to claim 10 , wherein the casing includes a plurality of casing components joined to one another at hermetically sealed seams.