Microwave surface coagulator with retractable blade

1. A surgical instrument, comprising:

a housing having an actuator operatively associated therewith;

a shaft extending distally from the housing, the shaft including:

a feedline having an inner conductor;

an outer conductor disposed coaxially about the inner conductor;

a wire conduit disposed along a longitudinal axis of the shaft; and

a pull wire disposed within the wire conduit and having a proximal and a distal end, wherein a proximal end of the pull wire is operably coupled to the actuator; and

an aperture assembly coupled to a distal end of the shaft, the aperture assembly including:

a reflector operably coupled to the outer conductor and having a closed hemispherical shaped upper portion and an open lower portion;

an antenna disposed within the reflector and operably coupled to the inner conductor;

a blade mounted within the reflector and pivotable between at least a closed position and an open position, wherein a distal end of the pull wire is operably coupled to the blade; and

a bottom cover enclosing the open lower portion of the reflector.

2. The surgical instrument in accordance with claim 1 , wherein the wire conduit is disposed within the shaft.

3. The surgical instrument in accordance with claim 1 , wherein the wire conduit is disposed on an outer surface of the shaft.

4. The surgical instrument in accordance with claim 1 , further comprising a biasing member configured to bias the blade toward the closed position.

5. The surgical instrument in accordance with claim 1 , wherein the bottom cover is constructed from radiofrequency-transparent material.

6. The surgical instrument in accordance with claim 1 , the housing further comprising a rotating assembly operably coupled to a proximal end of the shaft and configured to facilitate the rotation of the shaft about a longitudinal axis thereof.

7. The surgical instrument in accordance with claim 1 , further comprising a lubricious coating disposed on at least one of an outer surface of the shaft or an outer surface of the closed upper portion of the reflector.

8. The surgical instrument in accordance with claim 7 , wherein the lubricious coating is formed from material selected from the group consisting of polytetrafluoroethylene, polyethylene tephthalate, and parylene.

9. The surgical instrument in accordance with claim 1 , further comprising a dielectric region disposed between an inner surface of the reflector and the antenna.

10. The surgical instrument in accordance with claim 1 , wherein the shaft further includes a tubular divider concentrically disposed between the inner conductor and the outer conductor to form an inflow conduit and an outflow conduit.

11. The surgical instrument in accordance with claim 10 , wherein a distal opening of at least one of the inflow conduit and the outflow conduit are in fluid communication with an internal volume of the reflector.

12. The surgical instrument in accordance with claim 10 , wherein a proximal end of the inflow conduit is adapted to operably couple to source of coolant.

13. The surgical instrument according to claim 1 , wherein the blade is disposed within the open lower portion when the blade in the closed position and extends at least partially from the open lower portion when the blade is in the open position.

14. The surgical instrument according to claim 1 , wherein the inner conductor is operably coupled to a radiating section disposed within the reflector.

15. The surgical instrument according to claim 14 , wherein the blade is disposed within a cavity defined within the radiating section when the blade is in the closed position.

16. A surgical ablation system, comprising:

a source of microwave ablation energy;

a surgical instrument operably coupled to the source of ablation energy, the instrument comprising:

a housing having an actuator operatively associated therewith;

a shaft extending distally from the housing, the shaft including:

a feedline having an inner conductor;

an outer conductor disposed coaxially about the inner conductor;

a wire conduit disposed along a longitudinal axis of the shaft; and

a pull wire disposed within the wire conduit and having a proximal and a distal end, wherein a proximal end of the pull wire is operably coupled to the actuator; and

an aperture assembly coupled to a distal end of the shaft, the aperture assembly including:

a reflector operably coupled to the outer conductor and having a closed hemispherical shaped upper portion and an open lower portion;

an antenna disposed within the reflector and operably coupled to the inner conductor;

a blade mounted within the reflector and pivotable between at least a closed position and an open position, wherein a distal end of the pull wire is operably coupled to the blade; and

a bottom cover enclosing the open lower portion of the reflector.

17. The surgical ablation system in accordance with claim 16 , wherein the instrument housing further comprises a rotating assembly operably coupled to a proximal end of the shaft and configured to facilitate the rotation of the shaft about a longitudinal axis defined by the shaft.

18. The surgical ablation system in accordance with claim 16 , wherein the shaft further includes a tubular divider concentrically disposed between the inner conductor and the outer conductor to form an inflow conduit and an outflow conduit.

19. The surgical ablation system in accordance with claim 18 , further comprising a source of coolant adapted to operably couple to the inflow conduit.

20. The surgical ablation system in accordance with claim 18 , further comprising a fluid evacuation pump operably coupled to the outflow conduit.