Flexible instruments and associated systems and methods are disclosed herein. In some embodiments, a flexible instrument comprises an elongate device having an inner conductor, an outer conductor surrounding the inner conductor, and a dielectric layer insulating the inner conductor from the outer conductor. The flexible instrument further includes a recess formed in the outer conductor. An insert is positioned within the recess and about the inner conductor.

An electrosurgical device (10) operable to deliver microwave energy to cause targeted tissue ablation is provided. The electrosurgical device (10) comprises an antenna (26), a reflector (30), and a dielectric material (34) disposed therebetween. The selection of the dielectric material (30) and the relative positioning of the antenna (26) and the reflector (30) provide impedance matching between the antenna (26) and a transmission line (12) so as to minimize heating along the length of the device (10) during use.

An ablation device includes a feedline including an inner conductor having a distal end, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween, an elongated electrically-conductive member longitudinally disposed at the distal end of the inner conductor and having a proximal end, a first balun structure disposed over a first portion of the outer conductor and positioned so that a distal end of the first balun structure is located at a first distance from the proximal end of the electrically-conductive member and a second balun structure disposed over a second portion of the outer conductor and positioned so that a distal end of the second balun structure is located at a second distance from the proximal end of the electrically-conductive member.

An electrosurgical device (10) operable to deliver microwave energy to cause targeted tissue ablation is provided. The electrosurgical device (10) comprises an antenna (26), a reflector (30), and a dielectric material (34) disposed therebetween. The selection of the dielectric material (30) and the relative positioning of the antenna (26) and the reflector (30) provide impedance matching between the antenna (26) and a transmission line (12) so as to minimize heating along the length of the device (10) during use.

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.

An electrosurgical device having a radiating tip portion for delivering electromagnetic energy to biological tissue, where the electrosurgical device is disposed in a catheter. The electrosurgical device is movable relative to the catheter between a deployed position where the radiating tip portion is exposed and a retracted position where the radiating tip portion is contained within the catheter. In this manner, the radiating tip portion may be retracted until the moment when it is to be used. This may facilitate insertion of the device through an instrument channel of a surgical scoping device. In particular, this may prevent the radiating tip portion from catching on the instrument channel when the device is inserted into the instrument channel, which could cause damage to the instrument channel and/or radiating tip portion.

An electrosurgical system for treating biological tissue that comprises: an electrosurgical generator to supply microwave energy; a surgical scoping device having a steerable insertion cord for insertion to a treatment site; and an electrosurgical instrument dimensioned to fit within an instrument channel that is located within the insertion cord. The electrosurgical instrument comprises: a flexible coaxial cable arranged to convey the microwave energy; and a radiating tip portion connected at an end of the coaxial cable and configured to receive microwave energy. The radiating tip portion comprises: a coaxial transmission line for conveying the microwave energy; and a needle tip mounted at an end of the proximal coaxial transmission line, wherein the electrosurgical instrument is slidable within the instrument channel to extend the needle tip beyond an end of the instrument channel to puncture biological tissue; the needle tip is arranged to deliver the microwave energy into biological tissue.

A microwave apparatus comprises: a microwave feed line configured to deliver microwave energy having a selected operational frequency or range of frequencies to a radiating element extending from or coupled to a distal end of the microwave feed line; the radiating element; and a reactive element formed in or on the microwave feed line; wherein the operational frequency or range of frequencies is selected such that the reactive element both provides a desired degree of match between an impedance of the radiating element and an impedance of the microwave feed line, and reduces or eliminates surface currents flowing on a ground of the feed line.

An electrosurgical snare, e.g. suitably sized for insertion down the instrument channel of an endoscope, arranged to radiate microwave frequency energy (e.g. having a frequency greater than 1 GHz) from an elongate conductive element within an area encircled by a retractable loop. The elongate conductive element and retractable loop may be independently slidable relative to a snare base at a distal end of a sleeve to provide an appropriate device configuration. By controlling the shape of the emitted microwave field, the risk of collateral thermal damage can be reduced.

A microwave ablation device including a cable assembly configured to connect a microwave ablation device to an energy source and a feedline in electrical communication with the cable assembly. The microwave ablation device further includes a balun on an outer conductor of the feedline, and a temperature sensor on the balun sensing the temperature of the balun.