Energy-delivery devices with flexible fluid-cooled shaft, inflow/outflow junctions suitable for use with same, and systems including same

1. An ablation device, comprising:

a feedline including an inner conductor having a distal end, an outer conductor coaxially-disposed around the inner conductor and having a distal end, and a dielectric material disposed therebetween; and

an antenna assembly including:

an electrically-conductive proximal arm having a proximal end and a distal end, the proximal end electrically coupled to and coaxially-disposed about the distal end of the outer conductor;

an electrically-conductive distal arm including a proximal portion having an outer diameter and a distal portion having an outer diameter less than the outer diameter of the proximal portion; and

a junction member, wherein the electrically conductive proximal arm and the electrically-conductive distal arm align at the junction member and are spaced apart a length by the junction member, thereby defining a feed gap therebetween.

2. The ablation device of claim 1 , wherein the electrically-conductive proximal arm defines a first cavity therein extending from the distal end of the outer conductor to the distal end of the proximal arm.

3. The ablation device of claim 2 , wherein the proximal portion of the distal arm defines a second cavity therein.

4. The ablation device of claim 3 , wherein the junction member is at least partially disposed within the first and second cavities.

5. The ablation device of claim 4 , wherein a portion of the inner conductor of the feedline extends beyond the outer conductor and the dielectric material at a distal end of the feedline.

6. The ablation device of claim 5 , wherein the portion of the inner conductor that extends beyond the outer conductor and the dielectric material at a distal end of the feedline extends longitudinally through the junction member.

7. The ablation device of claim 6 , wherein the distal portion of the electrically-conductive distal arm of the antenna assembly defines a third cavity therein.

8. The ablation device of claim 7 , wherein the portion of the inner conductor further extends at least partially into the third cavity.

9. The ablation device of claim 1 , further comprising a balun structure disposed proximal to the antenna assembly.

10. The ablation device of claim 9 , wherein the balun structure is a quarter-wave sleeve balun.

11. A system, comprising:

an electrosurgical energy source; and

an ablation device operably associated with the electrosurgical energy source, the ablation device including:

a feedline including an inner conductor having a distal end, an outer conductor coaxially-disposed around the inner conductor and having a distal end, and a dielectric material disposed therebetween; and

an antenna assembly operatively coupled to the feedline, the antenna assembly including:

an electrically-conductive proximal arm having a proximal end and a distal end, the proximal end electrically coupled to and coaxially-disposed about the distal end of the outer conductor, wherein the electrically-conductive proximal arm defines a first cavity therein extending from the distal end of the outer conductor to the distal end of the electrically-conductive proximal arm; an electrically-conductive distal arm including a proximal portion having an outer diameter and a distal portion having an outer diameter less than the outer diameter of the proximal portion, wherein the proximal portion defines a second cavity therein; and

a junction member at least partially disposed in the first and second cavities, wherein the electrically-conductive proximal arm and the electrically-conductive distal arm align at the junction member and are spaced apart a length by the junction member, thereby defining a feed gap therebetween.

12. The system of claim 11 , further comprising an end-cap assembly, including a connector portion defining an interior lumen therein, the interior lumen configured to contain at least a portion of the antenna assembly therein.

13. The system of claim 12 , wherein the end-cap assembly further includes an end cap disposed at a distal end of the connector portion and coupled thereto.

14. The system of claim 13 , wherein the end cap is configured to define a proximal chamber portion therein, the proximal chamber portion configured to contain the proximal portion of the electrically-conductive distal arm of the antenna assembly therein.

15. The system of claim 14 , wherein the proximal chamber portion is disposed in fluid communication with the interior lumen and configured to circulate coolant fluid around the proximal portion of the electrically-conductive distal arm of the antenna assembly.

16. The system of claim 15 , wherein the end cap is further configured to define a distal chamber portion therein, the distal chamber portion configured to contain the distal portion of the electrically-conductive distal arm of the antenna assembly therein.

17. The system of claim 16 , wherein the distal chamber portion is disposed in fluid communication with the proximal chamber portion and configured to circulate the coolant fluid around the distal portion of the electrically-conductive distal arm of the antenna assembly.

18. The system of claim 12 , further comprising a coolant supply system in fluid communication with the interior lumen.

19. The system of claim 18 , further comprising a flexible, fluid-cooled shaft including an outer tubular member sealingly connected to a proximal portion of the connector portion and fluidly coupled to the interior lumen.

20. The system of claim 19 , further comprising an inflow/outflow junction adapted to be coupled in fluid communication with the coolant supply system and adapted to be coupled in fluid communication with the flexible, fluid-cooled shaft.