Electrosurgical forceps in which one or more pairs of non-resonant unbalanced lossy transmission line structures are arranged on the inner surfaces of the jaws of the forceps provide both (i) active and return electrodes for a radiofrequency (RF) signal, and (ii) lossy structures for delivering a microwave signal into biological tissue in conjunction with a mechanical gripping arrangement for applying pressure to material held within the jaws. The location of the pairs of transmission lines on the jaws of the forceps and the selection of the material of the jaws is arranged to ensure that any biological tissue gripped by the jaws become the propagation medium for the RF signal and the medium into which the microwave signal is lost.

Devices and methods for treating tissue with microwave energy used in applications such as destroying a soft tissue by microwave ablation and/or creating point, line, area or volumetric lesions. Various embodiments of flexible, low-profile devices are also disclosed where such device can be inserted non-invasively or minimally invasively near or into the target tissue such as cardiac tissue. The devices disclosed herein comprise antennas wherein the field profile generated by an antenna is tailored and optimized for a particular clinical application. The antennas use unique properties of microwaves such as interaction of a microwave field with one or more conductive or non-conductive shaping elements to shape or redistribute the microwave field.

Microwave antennas and devices incorporating such antennas usable for performing procedures on or within a patient's body using a shaped microwave field.

Devices and methods for treating tissue with microwave energy used in applications such as destroying a soft tissue by microwave ablation and/or creating point, line, area or volumetric lesions. Various embodiments of flexible, low-profile devices are also disclosed where such device can be inserted non-invasively or minimally invasively near or into the target tissue such as cardiac tissue. The devices disclosed herein comprise antennas wherein the field profile generated by an antenna is tailored and optimized for a particular clinical application. The antennas use unique properties of microwaves such as interaction of a microwave field with one or more conductive or non-conductive shaping elements to shape or redistribute the microwave field.

An electrosurgical device (10) is provided that is operable to deliver microwave energy within a controlled angular expanse to cause targeted tissue ablation. The device (10) comprises a blocking or reflecting material such as cylindrical members (34) that are laterally spaced from the antenna (20) that is operable to emit the microwave energy. The reflecting material creates regions in and/or surrounding the device into which sensors (51), such as thermocouple wires, may be placed to monitor a condition associated with the device or the patient's body.

A novel microwave ablation applicator includes a flexible tubular shaft and a partially encapsulated antenna. The applicator is adapted to be used with an endoscope in order to access remote targets deep within an organ of a patient. Microwave power is emitted from the antenna in a desired radiation pattern by circulating an attenuating liquid through the shaft and across a portion of the antenna. Microwave ablation systems and methods are described.

An electrosurgical apparatus for treating fluid-filled biological growths by replacing the fluid within the growth with a substance that assists in delivering treatment energy. The treatment energy may be microwave energy or may be thermal energy derived from microwave energy. The apparatus comprises an instrument having a radiating tip portion, and a fluid delivery mechanism for transporting fluid to and from a treatment zone located around the radiating tip portion. The fluid delivery mechanism comprises a rigid insertion element arranged to extend into the treatment zone, whereby fluid can be aspirated from the treatment zone, and a substance injected into the treatment zone to replace the aspirated fluid. The injected substance has dielectric properties selected to facilitate uniform delivery of treatment energy to biological tissue in the treatment zone.

The invention comprises novel microwave antennas wherein the microwave field profile generated by an antenna is tailored and optimized for a particular clinical application. The antennas disclosed herein incorporate one or more additional elements called shaping elements that use unique properties of microwaves such as interaction of a microwave field with one or more conductive or non-conductive elements to shape or redistribute the microwave field. Such shaping elements may be used to reduce the undesired backward coupling of the emitted microwave field to the transmission line. Such shaping elements may be used to increase the power efficiency of the antenna. The invention also discloses devices and methods for treating tissue with microwave energy emitted from the antennas for use in applications such as destroying a soft tissue by microwave ablation.

A method for forming a resonating structure within a body lumen, the method including advancing a flexible microwave catheter into a body lumen of a patient, the flexible microwave catheter including a radiating portion at the distal end of the flexible microwave catheter, the radiating portion configured to receive microwave energy, and at least one centering device proximate the radiating portion configured to deploy radially outward from the flexible microwave catheter; positioning the radiating portion near tissue of interest; deploying the at least one centering device radially outward from the flexible microwave catheter within the body lumen such that a longitudinal axis of the radiating portion is substantially parallel with and at a fixed distance from a longitudinal axis of the body lumen near the targeted tissue; and delivering microwave energy to the radiating portion such that a circumferentially balanced resonating structure is formed with the body lumen.

An introducer set for a microwave ablation probe is disclosed. The introducer set includes a cannula that is at least partially transparent to microwave energy, and a stylet sized to be received by the lumen of the cannula. Other examples provide a microwave ablation system including a microwave ablation probe having a radiating portion and a cannula that is at least partially transparent to microwave energy. The radiating portion of the probe aligns with the transparent portion of the cannula when the probe is inserted into the cannula lumen. The technology provides a method including introducing a microwave ablation probe into the lumen of a cannula having a cannula body that is at least partially transparent to microwave energy, aligning the transparent portion of the cannula with the radiating portion of the probe, and causing microwave energy to be emitted from the radiating portion of the probe.