Abstract: An isolating circuit for an electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissues is provided. The generator has an RF channel and a microwave channel which are combined at a signal combiner to enable the RF energy and microwave energy to be delivered into tissues along a common feed path. The isolating circuit includes a tunable wavelength isolator at a junction between the microwave channel and the signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another while providing a high withstanding voltage.

Abstract: A biopsy forceps tool (preferably for endoscopic use) in which microwave energy is used to coagulate bleeding after a biological tissue sample is collected between a pair of jaws. The pair of jaws define an enclosure that is isolated from the microwave energy itself and insulated from any thermal changes that occur due to application of the microwave energy. The tool comprises a pair of jaws connected to a coaxial cable, each of the pair of jaws comprising an electrically conductive shell, the jaw assembly being movable between a closed position in which the electrically conductive shells enclose an internal volume for holding a tissue sample and an open position in which the internal volume is exposed in order to receive the tissue sample. The electrically conductive shells form a Faraday cage around the internal volume when in the closed position.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: The disclosure relates to three enhancements for a surgical snare: an electrosurgical snare in which the loop of snare wire extends from an energy transfer surface which can act both as a physical reaction surface for mechanical cutting using the snare and as a region for emitting electromagnetic energy; a surgical snare having a snare wire having a first end connected to a movable boss that is slidably mounted on a coaxial cable; and a surgical snare having an end cap with a distally facing reaction surface and a pair of channels for guiding a snare wire, where the distally facing reaction surface is arranged to contact the retractable loop when fully retracted.

Abstract: An electrosurgical instrument for delivering microwave energy having a predetermined frequency into biological tissue in contact with the instrument, wherein the instrument comprises a first coaxial transmission line having a second coaxial transmission line connected to the distal end thereof, the second coaxial transmission line having a length and a characteristic impedance that are configured to match the impedance of the first coaxial transmission line to the load impedance at the distal end of the distal coaxial transmission line when the instrument is in contact with the tissue, at the operating frequency.

Abstract: Embodiments of the invention provide a hollow cable for transmitting radiofrequency and/or microwave frequency energy to an electrosurgical instrument, wherein the hollow cable is provided with electrical connectors for forming a bipolar electrical connection with an electrosurgical instrument that fits within, e.g. slides relative to, the hollow cable. The connectors can be conductive protrusions extending in an axial direction on opposite sides of the cable. The protrusions can be tabs, fins, rods, pins, or wires. The protrusions can be strips which engage corresponding terminals on the instrument. The transmission line structure of the invention can have a greater diameter than conventional coaxial cables, which can minimize loss whilst still providing access for control wires and/or fluid to reach a surgical instrument. The cable can be used with multiple instruments.

Abstract: Embodiments of the invention provide a hollow cable for conveying radiofrequency and/or microwave frequency energy to an electrosurgical instrument that can fit within, e.g. slide relative to, the hollow cable. The hollow cable provides a bipolar electrical connection to the electrosurgical instrument that is maintained when the electrosurgical instrument is rotated relative to the hollow cable. The cable may comprise a hollow coaxial transmission line having a rotatable component mounted at its distal end. The rotatable component comprises a longitudinal passageway continuous with the hollow coaxial transmission line. The rotatable component is rotatable relative to the transmission line and comprises a first and second conductive portions that are respectively electrically connected to first and second terminals on the coaxial transmission line and which are configured to maintain an electrical connection with their respective terminal when rotated relative to the coaxial transmission line.

Abstract: Embodiments of the invention provide an energy conveying structure for delivering RF and/or microwave energy to an electrosurgical instrument, where the energy conveying structure is incorporated into an insertion tube of a surgical scoping device (e.g. endoscope, laparoscope or the like). The insertion tube is a flexible conduit that is introduced into a patient's body during an invasive procedure, and can include an instrument channel and an optical channel. The energy conveying structure may be a layered coaxial structure that formed a liner that fits within the scoping device, e.g. within an instrument channel. Alternatively, the energy conveying structure may be a coaxial structure integrally formed as part of the flexible conduit.

Abstract: A surgical snare comprising a means of delivering thermal plasma on to biological tissue encircled by the snare. The snare may be “cold” snare, i.e. formed from insulating material, or active, i.e. connected to receive RF and/or microwave energy to be radiated into the area encircled by the snare. The surgical snare may thus deliver into biological tissue encircled by a retractable loop any one of (i) a plasma to perform surface coagulation, (ii) a non-ionising microwave field (in the absence of plasma) to perform coagulation at a deeper level, and (iii) an RF field to assist with cutting.

Abstract: An isolating circuit for electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissue. The generator has an RF channel and a microwave channel which are combined at signal combiner to enable the RF energy and microwave energy to be delivered into tissue along a common feed path. The isolating circuit comprises a tunable waveguide isolator at a junction between the microwave channel and signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another whilst providing a high withstanding voltage.

Abstract: 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.

Abstract: A calibration method and apparatus for surgical antennas arranged to deliver microwave radiation into biological tissue. An emitting region of the antenna is exposed to a plurality of calibration standards having different complex impedances at the treatment frequency. Calibration standards are created in a short-circuit-terminated waveguide cavity of variable length. In another variation, each calibration standard is a different mixture of liquids. Measurement of the magnitude and phase of signals reflected from the emitting region when exposed to the calibration standard permits calibration of the antenna; Also disclosed is a tissue treatment apparatus having an ablation channel for conveying microwave radiation to a surgical antenna at a high power level, with a separate measurement channel for conveying radiation at a low power level. A surgical antenna having an impedance transformer for matching a coaxial feed structure that terminates in radiating elements with tissue to be treated is also disclosed.

Abstract: An electrosurgical instrument for applying to biological tissue RF electromagnetic energy and/or microwave frequency EM energy, wherein the instrument tip has a protective hull with a smoothly contoured convex undersurface facing away from a planar body, and wherein the planar body has a tapering distal edge, and wherein an underside of the planar body extends beyond the protective hull at the tapering distal edge. Also disclosed herein is an interface joint for integrating into a single cable assembly all of (i) a fluid feed, (ii) a needle movement mechanism, and (iii) an energy feed (e.g. a coaxial cable), and a torque transfer device for permitting controlled rotation of the cable assembly within the instrument channel of an endoscope. The interface joint and torque transfer device may be integrated as a single component.

Abstract: Electrosurgical forceps for delivering microwave energy into biological tissue from a non-resonant unbalanced lossy transmission line structure located within or formed by the jaws of the forceps. The transmission line structure may be formed across the gap between the jaw element by opposed conductive elements, which are respectively electrically connected to inner and outer conductors of a coaxial cable. Alternatively, each jaw element may comprise its own lossy transmission line, whereby a power splitter is used to divide microwave energy from the coaxial cable. The forceps may be used endoscopically in the gastrointestinal tract or laparoscopically or in open surgery.

Abstract: 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.

Abstract: An electrosurgical device that is capable of both generating a plasma to perform surface coagulation and emitting a non-ionising microwave field (in the absence of plasma) to perform coagulation at a deeper level. The device comprises a probe tip that is connected to receive radiofrequency (RF) and/or microwave frequency energy from a generator, and also defines a flow path for a gas. The probe tip is adjustable between a first configuration, in which it defines a bipolar (e.g. coaxial) structure to produce a high electric field from the received RF and/or microwave frequency energy across the flow path for the gas to strike and sustain plasma and a second configuration, in which it defines an antenna structure to emit non-ionising microwave energy into tissue.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: An electrosurgical resection instrument for applying to biological tissue radiofrequency electromagnetic energy has a protective hull comprising a shaped piece of dielectric material mounted to cover an underside of an instrument tip of the instrument. The protective hull acts as a shield to protect tissue that may lie under the instrument tip from damage during treatment. The instrument may be particularly useful in procedures performed in a gastrointestinal tract, where bowel perforation is a concern, or in the pancreas, where damage to the portal vein or the pancreatic duct may occur when a tumour or other abnormality is being resected, dissected or removed.

Abstract: A calibration method and apparatus for surgical antennas arranged to deliver microwave radiation into biological tissue. An emitting region of the antenna is exposed to a plurality of calibration standards having different complex impedances at the treatment frequency. Calibration standards are created in a short-circuit-terminated waveguide cavity of variable length. In another variation, each calibration standard is a different mixture of liquids. Measurement of the magnitude and phase of signals reflected from the emitting region when exposed to the calibration standard permits calibration of the antenna; Also disclosed is a tissue treatment apparatus having an ablation channel for conveying microwave radiation to a surgical antenna at a high power level, with a separate measurement channel for conveying radiation at a low power level. A surgical antenna having an impedance transformer for matching a coaxial feed structure that terminates in radiating elements with tissue to be treated is also disclosed.