Microwave tissue dissection and coagulation

1. A surgical instrument, comprising:

a handle;

a shaft defining a longitudinal axis and extending distally from the handle, the shaft including:

an outer hypotube;

a lumen coaxially-disposed within the hypotube and extending beyond a distal end thereof; and

a coaxial feedline coaxially-disposed within the lumen and having an inner conductor and an outer conductor disposed coaxially about the inner conductor; and

a dissecting head assembly coupled to a distal end of the shaft, the dissecting head assembly including:

a dielectric core having a substantially planar radiating surface and at least one non-radiating surface, the substantially planar radiating surface defining a plane that is substantially parallel to the longitudinal axis, wherein the inner conductor and the outer conductor of the coaxial feedline are disposed within the dielectric core;

a reflective coating disposed on the at least one non-radiating surface of the dielectric core; and

a blade extending from the substantially planar radiating surface.

2. The surgical instrument in accordance with claim 1 , further comprising a coolant tube coaxially-disposed between the lumen and the coaxial feedline to form an inflow conduit and an outflow conduit.

3. The surgical instrument in accordance with claim 2 , wherein a distal opening of at least one of the inflow conduit or the outflow conduit are in fluid communication with a coolant chamber defined within the dissecting head assembly.

4. The surgical instrument in accordance with claim 1 , wherein the dissecting head assembly further includes a lubricious coating disposed on at least one of the reflective coating or the substantially planar radiating surface.

5. The surgical instrument in accordance with claim 1 , wherein the blade is oriented substantially perpendicular to the longitudinal axis of the shaft and the plane of the substantially planar radiating surface.

6. The surgical instrument in accordance with claim 1 , wherein the blade has a cutting edge oriented in a proximal direction toward the handle such that the cutting edge cuts tissue when the dissecting head assembly is drawn in the proximal direction.

7. The surgical instrument in accordance with claim 1 , wherein the dissecting head assembly has a shape selected from the group consisting of a generally wedge-like shape, a generally hemispherical shape, a generally elongated hemispherical shape, a generally clamshell shape, a generally parabolic shape, a generally cylindrical shape, a generally semicylindrical shape, a generally conical shape, a generally discoid shape, and a generally frustoconical shape.

8. The surgical instrument in accordance with claim 2 , wherein a proximal end of the inflow conduit is adapted to operably couple to source of coolant.

9. The surgical instrument in accordance with claim 1 , wherein a proximal end of the coaxial feedline is adapted to operably couple to source of coagulation energy.

10. The surgical instrument in accordance with claim 1 , wherein the blade is electrically isolated from the inner conductor and the outer conductor.

11. A surgical dissection and coagulation system, comprising:

a source of microwave coagulation energy;

a surgical instrument adapted to operably couple to the source of coagulation energy, the surgical instrument comprising:

a handle;

a shaft defining a longitudinal axis and extending distally from the handle, the shaft including:

an outer hypotube;

a lumen coaxially disposed within the hypotube and extending beyond a distal end thereof; and

a coaxial feedline coaxially-disposed within the lumen and having an inner conductor and an outer conductor-disposed coaxially about the inner conductor; and

a dissecting head assembly coupled to a distal end of the shaft, the dissecting head assembly including:

a dielectric core having a substantially planar radiating surface and at least one non-radiating surface, the substantially planar radiating surface defining a plane that is substantially parallel to the longitudinal, wherein the inner conductor and the outer conductor of the coaxial feedline are disposed within the dielectric core;

a reflective coating disposed on the at least one non-radiating surface of the dielectric core; and

a blade extending from the substantially planar radiating surface.

12. The surgical dissection and coagulation system in accordance with claim 11 , further comprising a coolant tube coaxially-disposed between the lumen and the coaxial feedline to form an inflow conduit and an outflow conduit.

13. The surgical dissection and coagulation system in accordance with claim 12 , wherein a distal opening of at least one of the inflow conduit or the outflow conduit are in fluid communication with a coolant chamber defined within the dissecting head assembly.

14. The surgical dissection and coagulation system in accordance with claim 11 , wherein the blade is oriented substantially perpendicular to the longitudinal axis of the shaft and the plane of the substantially planar radiating surface.

15. The surgical dissection and coagulation system in accordance with claim 11 , wherein the blade has a cutting edge oriented in a proximal direction toward the handle such that the cutting edge cuts tissue when the dissection head assembly is drawn in the proximal direction.

16. The surgical dissection and coagulation system in accordance with claim 12 , further comprising a source of coolant.

17. The surgical dissection and coagulation system in accordance with claim 16 , wherein a proximal end of the inflow conduit is adapted to operably couple to the source of coolant.

18. The surgical dissection and coagulation system in accordance with claim 11 , wherein the blade is electrically isolated from the inner conductor and the outer conductor.