Microwave ablation system
A microwave ablation catheter assembly is provided. A coaxial cable configured to connect to a microwave energy source at its proximal end and at its distal end to a distal radiating section. The coaxial cable includes inner and outer conductors and a dielectric positioned therebetween. An extended working channel is configured to receive the coaxial cable for positioning the coaxial cable adjacent target tissue. At least a portion of an inner surface of the extended working channel is electrically conductive. The electrically conductive inner surface of the extended working channel may function as a balun to maintain a balanced signal between the inner and outer conductors of the coaxial cable when the distal radiating section of the coaxial cable is energized.
1. A microwave ablation catheter assembly comprising:
an un-choked ablation catheter including:
a coaxial cable having a proximal portion and a distal portion, the proximal portion capable of being operatively connected to a microwave energy source, the coaxial cable including an inner conductor and an outer conductor; and
a radiator disposed at the distal portion of the coaxial cable; and
a flexible extended working channel configured to receive the ablation catheter for positioning the radiator adjacent target tissue, the flexible extended working channel having a balun, the balun including:
an outer insulating layer; and
a braided electrically conductive inner surface extending an entire length of the flexible extended working channel,
wherein the un-choked ablation catheter is selectively receivable through the flexible extended working channel to adjust an amount of energy transmitted to tissue and, upon application of microwave energy to the un-choked ablation catheter, energy conducted along the outer conductor of the coaxial cable is captured within the conductive inner surface of the flexible extended working channel and prevented from affecting tissue adjacent the flexible extended working channel.
2. The microwave ablation catheter assembly according to claim 1 , further comprising a location sensing system, wherein the un-choked ablation catheter and flexible extended working channel are configured to be placed within a patient using the location sensing system.
3. The microwave ablation catheter assembly according to claim 1 , wherein the flexible extended working channel includes a slot at its proximal end configured to releasably engage with a corresponding mechanical interface positioned on the un-choked ablation catheter.
4. The microwave ablation catheter assembly according to claim 3 , wherein the mechanical interface is moveable within the slot to lock the distal portion of the coaxial cable into at least one of a plurality of positions defined within the slot.
5. The microwave ablation catheter assembly according to claim 4 , wherein indicia is provided along the slot.
6. The microwave ablation catheter assembly according to claim 5 , wherein the indicia represents quarter-wavelength increments.
7. The microwave ablation catheter assembly according to claim 1 , wherein the outer insulating layer is configured to separate the electrically conductive inner surface from tissue adjacent the flexible extended working channel.
8. The microwave ablation catheter assembly according to claim 1 , wherein the inner conductor of the coaxial cable extends distally past the outer conductor of the coaxial cable and is in sealed engagement with the distal portion of the coaxial cable.
9. The microwave ablation catheter assembly according to claim 1 , wherein the un-choked ablation catheter further includes one or more cooling catheters surrounding the coaxial cable and radiator to provide a pathway for a cooling medium.
10. The microwave ablation catheter assembly according to claim 9 , wherein the cooling medium is a liquid or gas.
11. The microwave ablation catheter assembly according to claim 1 , wherein the flexible extended working channel provides a closed pathway for a cooling medium to circulate within the flexible extended working channel.
12. The microwave ablation catheter assembly according to claim 1 , wherein the flexible extended working channel provides an open pathway for a cooling medium to pass through the flexible extended working channel.
13. A microwave ablation system comprising:
a microwave energy source;
an un-choked ablation catheter including:
a coaxial cable having a proximal portion and a distal portion, the proximal portion being operatively connected to the microwave energy source, the coaxial cable including an inner conductor and an outer conductor; and
a radiator disposed at the distal portion of the coaxial cable; and
a flexible extended working channel configured to receive the un-choked ablation catheter for positioning the radiator adjacent target tissue, the flexible extended working channel having a balun, the balun including:
an outer insulating layer; and
a braided electrically conductive inner surface extending an entire length of the extended working channel,
wherein the un-choked ablation catheter is selectively receivable through the flexible extended working channel to adjust an amount of energy transmitted to tissue and, upon application of microwave energy to the un-choked ablation catheter, energy conducted along the outer conductor of the coaxial cable is captured within the conductive inner surface of the flexible extended working channel and prevented from affecting tissue adjacent the flexible extended working channel.
14. A microwave ablation catheter assembly, comprising:
an ablation catheter including:
a coaxial cable including an inner conductor and an outer conductor; and
a radiator disposed at a distal portion of the coaxial cable; and
a flexible extended working channel configured to receive the ablation catheter, the flexible extended working channel having a balun, the balun including:
an outer insulating layer; and
a braided electrically conductive inner surface that extends an entire length of the flexible extended working channel, wherein upon delivery of microwave energy to the ablation catheter while the ablation catheter is received within the flexible extended working channel, energy conducted along the outer conductor of the coaxial cable is captured within the braided electrically conductive inner surface of the flexible extended working channel and prevented from affecting tissue adjacent the flexible extended working channel.