Electrosurgical instruments

Abstract

An electrosurgical device having a radiating tip portion for delivering electromagnetic energy to biological tissue, wherein the electrosurgical device is arranged in a catheter. The electrosurgical device can be moved relative to the catheter between a deployed position in which the radiating tip portion is exposed and a retracted position in which the radiating tip portion is accommodated in the catheter. In this way, the radiating tip portion can be retracted until the moment when it is to be used. This can facilitate the insertion of the device through an instrument channel of a surgical viewing device. In particular, this can prevent the radiating tip portion from getting stuck on the instrument channel when the device is inserted into the instrument channel, which may cause damage to the instrument channel and / or the radiating tip portion.

Description

Technical Field

[0001] The present invention relates to an electrosurgical instrument for delivering electromagnetic energy to biological tissue in order to ablate target tissue. In particular, a probe is configured to be insertable through a passageway of a surgical scope or catheter that can be introduced to a treatment site in a non-invasive manner. The probe can be arranged to ablate tissue, such as a tumor, cyst or other lesion. The probe can be particularly suitable for pancreatic treatment. Background Art

[0002] Electromagnetic (EM) energy and in particular microwave and radio frequency (RF) energy have been found to be useful in electrosurgery because of their ability to cut, coagulate and ablate body tissue. Typically, an apparatus for delivering EM energy to body tissue includes a generator containing an EM energy source and an electrosurgical instrument connected to the generator for delivering energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into the patient's body. However, if, for example, the target site is in a thin-walled section of a moving lung or gastrointestinal (GI) tract, it may be difficult to position the instrument percutaneously in the body. Other electrosurgical instruments can be delivered to the target site by a surgical peep device (e.g., an endoscope) that can extend through a passage in the body, such as an airway or the lumen of the esophagus or colon. This allows minimally invasive treatment, which can reduce the mortality of the patient and reduce intraoperative and postoperative complication rates.

[0003] The technique of using endoscopic ultrasound guided radiofrequency ablation to treat pancreatic tissue is known (Pai, ​​M. et al.: Endoscopic ultrasound guided radiofrequency ablation, for pancreatic cysticneoplasms and neuroendocrine tumors, World J Gastrointest Surg 2015 April 27; 7 (4): 52-59). In this technique, a wire with a small diameter (e.g., 0.33 mm) is inserted through the working channel of an ultrasound-enabled endoscope. RF power is applied to the wire in conjunction with an external grounded return pad that contacts the patient's skin to coagulate tissue in the liver and pancreas. In order to ablate the lesion, it is necessary to energize for 90 to 120 seconds, and in some cases the wire is removed and repositioned. Summary of the invention

[0004] In general, the present invention provides an electrosurgical device having a radiating tip portion for delivering electromagnetic energy to biological tissue, wherein the electrosurgical device is disposed in a catheter. The electrosurgical device can be moved relative to the catheter between a deployed position in which the radiating tip portion is exposed and a retracted position in which the radiating tip portion is accommodated within the catheter. In this way, the radiating tip portion can be retracted until the moment when it is to be used. This can facilitate the insertion of the device through an instrument channel of a surgical viewing device. In particular, this can prevent the radiating tip portion from getting stuck on the instrument channel when the device is inserted into the instrument channel, which may cause damage to the instrument channel and / or the radiating tip portion.

[0005] This configuration may be particularly beneficial for treating tumors in the pancreas because the device can be positioned adjacent to the duodenal wall with the radiating tip portion in the retracted position. The radiating tip portion can then be exposed to pierce the duodenal wall and penetrate the pancreas where it can deliver electromagnetic energy to ablate target tissue. The radiating tip portion can be sized to fit into the pancreas to provide a rapid and precise alternative to known RF ablation techniques.

[0006] Although the present invention may find particular use in the pancreas, it may also be applicable to other difficult treatment sites such as the lungs, liver, etc.

[0007] According to a first aspect of the present invention, there is provided an electrosurgical instrument comprising: a flexible catheter having a lumen extending therethrough, the catheter being sized to be insertable through an instrument channel of a surgical peep device; and an electrosurgical device disposed within the lumen, the electrosurgical device comprising: a flexible coaxial cable configured to transmit microwave energy; and a radiating tip portion connected at a distal end of the coaxial cable to receive the microwave energy, the radiating tip portion having a smaller outer diameter than the flexible coaxial cable, wherein the radiating tip portion comprises: a proximal coaxial transmission line for transmitting the microwave energy; and a distal needle tip at a distal end of the proximal coaxial transmission line, the distal needle tip being configured to radiate the microwave energy into biological tissue, wherein the electrosurgical device is longitudinally movable within the lumen between a deployed position in which the distal needle tip protrudes beyond the distal end of the catheter and a retracted position in which the distal needle tip portion is accommodated within the catheter.

[0008] This configuration enables the radiating tip portion to be retracted into the catheter when not in use. In this way, the instrument can be manipulated into a suitable position with the radiating tip portion in the retracted position to facilitate manipulation of the instrument. Since the radiating tip portion has a smaller outer diameter than the coaxial cable, the radiating tip portion is more likely to get stuck in the instrument channel of the surgical viewing device or on tissue. By keeping the radiating tip portion in the retracted position while manipulating the instrument, such jamming of the radiating tip portion can be avoided.

[0009] The electrosurgical device may be moved along the lumen of the catheter using a suitable actuation mechanism. When the electrosurgical device is in the deployed position, all or a portion of the radiating tip portion may protrude beyond the distal end of the catheter. When the electrosurgical device is in the retracted position, the distal needle tip may be located inside the catheter so that it does not protrude beyond the distal end of the catheter. The electrosurgical device may be moved in a distal direction to move it to the deployed position, and the electrosurgical instrument may be moved in a proximal direction to move it to the retracted position.

[0010] The catheter can be formed by a tube made of a flexible biocompatible material. For example, the catheter can be made of a tube of polyetheretherketone (PEEK) or PTFE. As another example, the catheter can be made of a polyether block amide (e.g., ) material. The catheter can be made of a non-adhesive material (e.g., PTFE) or coated with a non-adhesive material to prevent tissue from adhering to the catheter. In order to fit within the instrument channel of the surgical peep device, the catheter can have an outer diameter equal to or less than 2.0 mm.

[0011] The lumen may be a longitudinal passage extending through the catheter. The lumen may be sized to receive an electrosurgical device and allow the electrosurgical device to pass therethrough.

[0012] The flexible coaxial cable can be a conventional low-loss coaxial cable that can be connected to an electrosurgical generator at a proximal end to receive microwave energy. The coaxial cable can have a center conductor separated from an outer conductor by a dielectric material. The coaxial cable can also include an outer protective sheath for insulating and protecting the cable. In some instances, the protective sheath can be made of or coated with a non-adhesive material to facilitate movement of the coaxial cable along the lumen. The radiating tip portion is located at the distal end of the coaxial cable and is connected to receive microwave energy transmitted along the coaxial cable.

[0013] The proximal coaxial transmission line is connected to the distal end of the coaxial cable to receive microwave energy transmitted by the coaxial cable. The proximal coaxial transmission line may have an inner conductor electrically connected to the center conductor of the coaxial cable. The proximal coaxial transmission line may also have a proximal dielectric sleeve disposed around the inner conductor and an outer conductor formed around the proximal dielectric sleeve. The outer conductor of the proximal coaxial transmission line may be electrically connected to the outer conductor of the coaxial cable.

[0014] The materials used in the proximal coaxial transmission line may be the same as or different from the materials used in the coaxial cable. The materials used in the proximal coaxial transmission line may be selected to provide a desired flexibility and / or impedance of the proximal coaxial transmission line. For example, the dielectric material of the proximal coaxial transmission line may be selected to improve impedance matching with the target tissue.

[0015] The dimensions of the components of the proximal coaxial transmission line may be selected to provide the proximal coaxial transmission line with an impedance that is the same as or similar to the impedance of the flexible coaxial cable (e.g., about 50Ω). The inner conductor may be formed of a material having a high conductivity (e.g., silver or copper). The inner conductor of the proximal coaxial transmission line may have a smaller outer diameter than the center conductor of the coaxial cable. This may facilitate bending of the radiating tip portion.

[0016] The distal needle tip is formed at the distal end of the proximal coaxial transmission line. The distal needle tip may include a transmitter structure that is arranged to receive microwave energy from the proximal coaxial transmission line and deliver the energy to the target tissue. The transmitter structure can be selected based on the type of energy to be delivered and the desired treatment method. For example, the transmitter structure may include a monopolar or bipolar microwave antenna for radiating microwave energy into surrounding tissue to perform tissue ablation. In other examples, the transmitter structure may include a pair of RF electrodes that are arranged to deliver radiofrequency energy to the target tissue. In such examples, the coaxial cable is arranged to deliver radiofrequency (RF) energy to an electrosurgical device that may be capable of performing ablation, coagulation and / or resection using RF energy. In some examples, the transmitter structure may be constructed to transmit both microwave energy and radiofrequency energy (simultaneously or sequentially).

[0017] As mentioned above, the outer diameter of the radiating tip portion is smaller than the outer diameter of the coaxial cable. By using a smaller diameter radiating tip portion, the size of the insertion hole created when the radiating tip portion is inserted into the target tissue can be reduced. This can reduce bleeding and allow the wound to heal faster. For example, when the device is inserted into the pancreas, this can reduce the size of the insertion hole formed in the duodenal wall. The inventors have also found that this configuration is beneficial for treating tumors in the liver, where bleeding from the insertion hole can be a problem.

[0018] In addition, by making the outer diameter of the radiating tip portion smaller than the outer diameter of the coaxial cable, the radiating tip portion can be more flexible than the coaxial cable. This can facilitate guiding the distal needle tip to a desired location, for example, where it is necessary to guide the device around a sharp bend. Thus, the present invention strikes a balance between using a coaxial cable with a relatively larger outer diameter to reduce the effects of heat loss and using a radiating tip portion with a relatively smaller diameter to provide improved flexibility and reduce tissue damage during insertion.

[0019] The distal needle tip is configured to operate as a half-wavelength converter to deliver microwave energy from the distal needle tip to biological tissue. The advantage of configuring the distal needle tip as a half-wavelength converter can be to minimize reflections at the interface between components (e.g., between the coaxial cable and the proximal coaxial transmission line and between the proximal coaxial transmission line and the distal needle tip). Due to the greater change in impedance, the reflection coefficient at the latter interface is generally greater. The half-wavelength configuration can minimize these reflections, so that the main reflection coefficient becomes the reflection coefficient of the interface between the proximal coaxial transmission line and the tissue. The impedance of the proximal coaxial transmission line can be selected to be the same as or close to the expected tissue impedance to provide a good match at the frequency of the microwave energy.

[0020] The catheter may include a constriction passage at its distal end, the constriction passage being sized to allow the radiation tip portion to pass through and prohibit the flexible coaxial cable from passing through. In one example, the constriction passage may extend through a plug mounted at the distal end of the catheter. The plug may be used to prevent tissue and / or fluid from entering the catheter from the treatment site. In addition, the constriction passage may be used to guide the radiation tip portion when the device moves between the retracted position and the deployed position. This can achieve precise positioning of the radiation tip portion, which can facilitate guiding the distal needle tip to the target treatment site. The constriction passage may be aligned with the longitudinal axis of the instrument so that the radiation tip portion is concentrated around the longitudinal axis. The plug may be made of an insulating material (e.g., PEEK) to avoid short circuits between the plug and the radiation tip portion.

[0021] The plug may cover the opening at the distal end of the catheter, for example, the plug may be a cap on the distal end of the catheter. The constricted passage may be sized to allow the radiating tip portion to pass through, but prevent the passage of a larger diameter coaxial cable. In this way, the constricted passage may be used to limit the movement of the electrosurgical device along the lumen in the distal direction. This may prevent the coaxial cable from being pushed out of the distal end of the catheter, thereby preventing injuries due to the larger diameter of the coaxial cable.

[0022] In some embodiments, the constriction passage may include a lip for removing biological tissue from the radiating tip portion when the electrosurgical device moves from the deployed position to the retracted position. For example, when the radiating tip portion is retracted into the catheter, the lip may be arranged to scrape tissue off the radiating tip portion. This prevents tissue from being entrained inside the catheter, which may contaminate the catheter or cause the instrument to malfunction (e.g., by constraining the movement of the electrosurgical device along the lumen). The lip may be disposed at the distal opening of the passage, for example, the lip may be disposed around the distal opening of the passage. In this way, tissue may be prevented from entering the passage. The lip may be a sharp edge surrounding the opening of the passage.

[0023] The distal surface of the catheter may be rounded. For example, the distal end surface of the plug may be rounded, for example, having a hemispherical form or a dome form. The rounded surface may avoid any sharp edges around the distal end of the catheter. This may facilitate inserting the instrument down into the working channel of the surgical peep instrument. In particular, this may facilitate moving the instrument through a bend in the working channel.

[0024] When in the retracted position, the distal needle tip can be retained in the contraction passage. For example, the proximal opening of the contraction passage can be located inside the catheter, and the distance between the proximal opening of the contraction passage and the distal opening of the contraction passage can be greater than the length of the distal needle tip. In other words, the length of the contraction passage can be greater than the length of the distal needle tip. In this way, when the radiating tip portion is in the retracted position, the distal needle tip can be completely contained within the contraction passage. The contraction passage can be defined in a body portion of the plug contained within the distal section of the catheter.

[0025] For example, due to the outer conductor of the proximal coaxial transmission line, the proximal coaxial transmission line can have a larger outer diameter than the distal needle tip. Therefore, there can be a lip or step at the interface between the distal needle tip and the proximal coaxial transmission line. By making the constriction passage longer than the distal needle tip, the lip at the interface between the distal needle tip and the proximal coaxial transmission line can be located within the constriction passage when the device is in the retracted position. In this way, the lip is prevented from getting stuck on the proximal opening of the constriction passage when the device is moved from the retracted position to the deployed position.

[0026] The proximal opening of the passage in the plug may be flared outward, for example, the diameter of the proximal opening may increase in the proximal direction. In this way, the proximal opening of the passage may act as a funnel to guide the radiating tip portion into the passage. This may facilitate movement of the electrosurgical device along the lumen and may prevent the radiating tip portion from getting stuck on the proximal opening of the passage.

[0027] In some embodiments, the stopper may include a main body portion disposed inside the catheter, the main body portion including a projection for fastening the stopper to the catheter. In this way, the stopper may be installed on the distal end of the catheter without the use of an adhesive. However, in some cases, an adhesive may be used to further fasten the stopper to the catheter. The projection may be, for example, a projection or a barb, which is arranged to press against the catheter outwardly to keep the stopper in place in the catheter. The stopper may be installed on the distal end of the catheter by pushing the main body portion of the stopper into the catheter. In this way, a "push fit" connection may be formed between the stopper and the distal end of the catheter.

[0028] The distal needle tip may include a pointed tip at its distal end. The pointed tip may be made of a rigid insulating material such as zirconium oxide or ceramic. Zirconia is a rigid dielectric material that can be sharpened to a fine point and is therefore particularly suitable for use as a pointed tip. The pointed tip may be used to pierce tissue to facilitate insertion of the radiating tip portion into the target tissue.

[0029] The distal needle tip may include a distal dielectric sleeve surrounding the central conductive element, and the pointed tip may be fastened in a hole at the distal end of the distal dielectric sleeve. The pointed tip may include a body disposed at the distal end of the distal dielectric sleeve, wherein the body of the pointed tip may include a protrusion for fastening the body in the hole. In this way, the pointed tip may be retained in the hole at the distal end of the distal dielectric sleeve. By disposing the body of the pointed tip in the hole of the distal dielectric sleeve, the pointed tip may be securely held in place. The protrusion may be, for example, a protrusion or a barb, which is arranged to press outward against the wall of the hole to keep the body in place in the hole. The pointed tip may be mounted on the distal end of the distal dielectric sleeve by pushing the body of the distal tip into the hole. In this way, a "push-fit" connection may be formed between the pointed tip and the distal dielectric sleeve. This configuration may enable the pointed tip to be mounted on the distal dielectric sleeve without an adhesive. However, in some cases, an adhesive may be used to further secure the pointed tip in place.

[0030] The pointed tip can be made of a dielectric material having a higher rigidity than the distal dielectric sleeve. This can make the pointed tip sharper to facilitate the piercing of tissue.

[0031] The proximal coaxial transmission line may include an inner conductor separated from an outer conductor by a dielectric sleeve, wherein the inner conductor includes a distal portion that protrudes beyond the distal end of the outer conductor, and wherein the distal needle tip includes the length of the distal portion of the inner conductor. Thus, the distal dielectric sleeve may surround the inner conductor, the inner conductor forming the central conductive element mentioned above.

[0032] The distal dielectric sleeve may be made of the same or different material than the dielectric material in the proximal coaxial transmission line. The distal dielectric sleeve may have a higher stiffness than the dielectric material of the proximal coaxial transmission line. Providing a higher stiffness to the distal dielectric sleeve may facilitate insertion of the distal needle tip into the target tissue, while having a lower stiffness proximal coaxial transmission line may facilitate bending of the radiating tip portion. This may enable the instrument to be guided through narrow and tortuous pathways while still enabling the instrument to be inserted into the target tissue. For example, the dielectric material of the proximal coaxial transmission line may be made of a flexible dielectric material (e.g., PTFE), and the distal dielectric sleeve may be made of, for example, ceramic, polyetheretherketone (PEEK), or glass-filled PEEK.

[0033] In some embodiments, the pointed tip may have a proximal portion tapered at a first taper angle relative to the longitudinal direction and a distal portion tapered at a second taper angle relative to the longitudinal direction, the first taper angle being less than the second taper angle. By making the distal section of the pointed tip have a larger taper angle, the fragility of the pointed tip may be reduced. This may reduce the likelihood of particles falling off the pointed tip and remaining in the body.

[0034] The outer conductor of the proximal coaxial transmission line can be made of a nickel titanium alloy. For example, the outer conductor can be formed of a nickel titanium alloy tube. The inventors have found that nickel titanium alloys exhibit longitudinal stiffness sufficient to transmit forces capable of penetrating the duodenal wall. In addition, the flexibility of nickel titanium alloys can facilitate bending of the radiating tip portion so that the instrument can be guided through a narrow tortuous passage. Therefore, forming the outer conductor of nickel titanium alloy can facilitate the use of the instrument to treat tumors in the pancreas.

[0035] The radiating tip portion may be secured to the coaxial cable by a collar mounted over a junction between the radiating tip portion and the coaxial cable, the collar having a rounded distal surface. The collar may be located at an interface between the distal end of the coaxial cable and the proximal end of the proximal coaxial transmission line. The distal surface of the collar may be a forward facing surface of the collar, i.e., a surface facing the distal end of the instrument. By providing a collar having a rounded distal surface, sharp edges at the interface between the coaxial cable and the proximal coaxial transmission line may be avoided. This may reduce friction between the electrosurgical device and the catheter as the electrosurgical device moves along the lumen. This may, for example, facilitate movement of the electrosurgical device along the lumen when the instrument is in a retroflexed state (e.g., when there is a bend in the catheter).

[0036] In some embodiments, the collar can be conductive and can electrically connect the outer conductor of the proximal coaxial transmission line to the outer conductor of the coaxial cable, and a dielectric spacer can be installed at the junction between the radiating tip portion and the coaxial cable, the dielectric spacer being disposed between the inner conductor of the proximal coaxial transmission line and the collar. For example, the dielectric spacer can be an insulating washer installed at the interface and disposed around the proximal end of the inner conductor. This can reduce the risk of a short circuit at the interface between the coaxial cable and the radiating tip portion, and improve electrical safety at the junction.

[0037] The length of the radiating tip portion may be equal to or greater than 140 mm. Coaxial cables (e.g., Sucoform 86 coaxial cables) commonly used in electrosurgical instruments typically have a large amount of tinned outer sheaths to enable longitudinal actuation of the cable. However, this results in the coaxial cable being relatively stiff, so that greater force is required to bend the coaxial cable. This may cause a large amount of friction when the device moves through a bend in the catheter, which may hinder precise control of the device. Having a long radiating tip portion may facilitate bending of the device near its distal end because the radiating tip portion may have greater flexibility compared to the coaxial cable. By making the radiating tip portion 140 mm or longer, it is possible to avoid having to move the coaxial cable through the curved distal portion of the catheter. This may, for example, facilitate deployment of the radiating tip portion when the distal portion of the catheter is in a flexed state. This configuration may be particularly beneficial for use in the pancreas, where it may be necessary to flex the distal portion of the instrument in a flexed state.

[0038] The radiation tip portion may have a non-adhesive material on its outer surface. For example, an outer sheath may be disposed on the proximal portion of the radiation tip portion, the outer sheath being made of or coated with a non-adhesive material. This may facilitate movement of the electrosurgical device along the lumen by reducing friction between the lumen and the radiation tip portion. This configuration may be particularly beneficial when combined with a long radiation tip portion (e.g., 140 mm or longer) because it may facilitate movement of the radiation tip portion through the distal portion of the catheter in a flexed state. The outer sheath may also be used to increase the effective outer diameter of the radiation tip portion, thereby reducing lateral movement of the radiation tip portion in the lumen. This may improve the positioning accuracy of the radiation tip portion. In some cases, the outer sheath may extend over all or a portion of the coaxial cable to reduce friction between the coaxial cable and the lumen.

[0039] In some embodiments, the outer sheath can be made of PTFE.For example, the outer sheath can be a PTFE tube disposed around the proximal portion of the radiating tip portion.

[0040] The proximal portion of the coaxial cable may be fastened to a rigid reinforcement element. The reinforcement element may be used to increase the longitudinal stiffness of the proximal portion of the coaxial cable. This may facilitate applying a force (e.g., a push or pull) to the proximal end of the coaxial cable in order to move the electrosurgical device along the lumen. This may improve control of the position of the electrosurgical device in the lumen. The reinforcement element may be disposed on an outer surface of the proximal portion of the coaxial cable.

[0041] In some embodiments, the reinforcing element can be a rigid tube disposed on the outer surface of the proximal portion of the coaxial cable. The rigid tube can have a higher longitudinal stiffness than the coaxial cable. For example, the rigid tube can be a metal (e.g., stainless steel) tube.

[0042] The proximal portion of the lumen may have a larger diameter than the distal portion of the lumen to receive the proximal portion of the coaxial cable. Due to the reinforcement element, the outer diameter of the proximal portion of the coaxial cable may be larger than the outer diameter of the distal portion of the coaxial cable. The catheter with a larger diameter proximal portion may enable the proximal portion of the coaxial cable to slide within the catheter without additional friction caused by the reinforcement element.

[0043] In some embodiments, the catheter may include a tapered portion at its distal end, and the tapered portion may taper from a first diameter at its proximal end to a second, smaller diameter at its distal end, the second diameter being larger than the outer diameter of the radiating tip portion and smaller than the outer diameter of the coaxial cable. In this way, the tapered portion may allow the radiating tip portion to pass through so that the radiating tip portion may protrude beyond the distal end of the catheter. Conversely, the tapered portion may be used to prevent the coaxial cable (which has a larger diameter than the radiating tip portion) from being pushed through the tapered portion, thereby preventing the coaxial cable from being accidentally exposed outside the distal end of the catheter.

[0044] In some cases, the tapered portion may define a distal opening of the catheter, wherein the diameter of the distal opening is the second smaller diameter. In this way, when the electrosurgical device is in the deployed position, the radiating tip portion may protrude through the distal opening in the tapered portion. Thus, the tapered portion may serve a function similar to the plug discussed above. The tapered portion may be used as a replacement for a plug at the distal end of the catheter, for example, to simplify the construction of the instrument. In some cases, the plug may be combined with the tapered portion, for example, the plug may be installed in the distal opening of the tapered portion.

[0045] In some embodiments, the inner conductor of the proximal coaxial transmission line can be formed of an inner core made of a first conductive material and an outer conductive coating made of a second conductive material having a higher conductivity than the first conductive material. The first conductive material can have a higher stiffness than the second conductive material. This can increase the longitudinal stiffness of the radiating tip portion, which can facilitate the transmission of forces along the radiating tip portion, for example, for piercing tissue. For example, the inner core can be made of stainless steel and the outer conductive coating can be made of silver.

[0046] According to a second aspect of the present invention, a handpiece for controlling the movement of an electrosurgical device along the lumen of a catheter is provided, the handpiece comprising: a first section having a connector for connecting the distal end of the handpiece to an instrument port of a surgical peep device; a second section connected to the first section and movable along the length of the first section, the second section having a retainer for retaining the proximal end of the catheter, whereby the relative movement between the second section and the first section is arranged to control the length of the catheter extending from the distal end of the handpiece; and a third section connected to the second section and movable along the length of the second section, the third section having a coaxial connector, the coaxial connector being arranged to receive the proximal end of a coaxial cable transmitted within the lumen of the catheter, whereby the relative movement between the third section and the second section is arranged to control the relative position of the coaxial cable within the catheter.

[0047] The handpiece of the second aspect of the invention may be used with the electrosurgical instrument of the first aspect of the invention to control the position of the electrosurgical device in a catheter. An independent aspect of the invention may provide an electrosurgical apparatus comprising the electrosurgical instrument of the first aspect and the handpiece of the second aspect, the handpiece being arranged to control the position of the electrosurgical device in a catheter.

[0048] Advantageously, the handpiece of the second aspect of the present invention enables the length of the catheter to be adjusted independently of the position of the electrosurgical device in the catheter. In this way, the length of the catheter can be adjusted so that it fits within the instrument channel of the surgical viewing device.

[0049] In use, the proximal end of the catheter of the electrosurgical instrument may be retained in the holder of the second section. In this way, the position of the catheter may be fixed relative to the second section. The second section may include a fixing mechanism for fixing the position of the second section relative to the first section. The fixing mechanism may, for example, include a clip, a clamp, or some other suitable mechanism for holding the proximal end of the catheter and securing it in place.

[0050] The proximal end of the coaxial cable may be connected to the coaxial connector in the third section. In this way, the position of the coaxial cable (and therefore the electrosurgical device) may be fixed relative to the third section. For example, the coaxial cable may include a connector at its proximal end, which is configured to mate with the coaxial connector in the third section. Alternatively, the coaxial cable may be directly connected to the coaxial connector in the third section, for example, by a soldered and / or welded electrical connection. The coaxial connector of the third section may be fastened to the body of the third section, for example, by screws or using an adhesive. The coaxial connector may be connected to an electrosurgical generator, for example, by an interface cable, to receive electromagnetic energy from the generator and transmit the electromagnetic energy to the coaxial cable.

[0051] The first section is used to anchor the handpiece relative to the input port of the instrument channel of the surgical viewing device. The connector on the first section can be configured to mate with a corresponding connector on the surgical viewing device. For example, the connector can be a Luer connector, which can enable a leak-free connection between the handpiece and the instrument channel. The connector may include a mechanism for fastening the handpiece to the surgical device, such as by a clamp or a threaded connection.

[0052] In use, the second section can be moved relative to the first section to adjust the length of the catheter protruding from the handpiece. Since the first section can be fixed relative to the instrument channel of the surgical viewing device, and the catheter can be fixed relative to the second section, moving the second section relative to the first section can control the length of the catheter in the instrument channel. In this way, the length of the catheter can be adjusted so that it fits the instrument channel.

[0053] Once the length of the catheter has been adjusted, the third section can be moved relative to the second section in order to move the electrosurgical device along the lumen of the catheter. Since the position of the catheter can be fixed relative to the second section, and the position of the electrosurgical device can be fixed relative to the third section, moving the third section relative to the second section can move the electrosurgical device along the lumen of the catheter. In this way, the position of the electrosurgical device in the lumen can be controlled by moving the third section relative to the second section.

[0054] As mentioned above, the second section may include a fixing mechanism for fixing the position of the second section relative to the first section. In this way, once the length of the catheter has been adjusted to the desired length, the length of the catheter can be fixed by fixing the position of the second section relative to the first section using the fixing mechanism. The fixing mechanism can be any suitable mechanism for reversibly fixing the position of the second section relative to the first section. For example, the fixing mechanism can include a screw for fixing the second section to the first section, or a clamp for fixing the second section to the first section.

[0055] The second section may include a limiter that can be moved along the length of the second section, and wherein the limiter is arranged to constrain the movement of the third section relative to the second section. Therefore, the position of the limiter can be adjusted to set the desired range of motion of the third section relative to the second section. This can be used to limit the extent to which the radiation tip portion can be exposed outside the distal end of the catheter. This can avoid accidentally pushing the radiation tip portion too far and possibly damaging healthy tissue. The limiter may, for example, have a stop surface that is arranged to abut against the third section when the third section moves in the distal direction to prevent the third section from moving further in the distal direction. The limiter may be a sliding member disposed on the surface of the second section. The limiter may include a fixing mechanism (e.g., a screw or a clamp) for fixing it in a desired position along the length of the second section.

[0056] In some embodiments, the second segment may include a first set of markings arranged to indicate a maximum range of motion of the electrosurgical device along the lumen based on the position of the limiter relative to the first set of markings. In this way, a desired range of motion of the electrosurgical device along the lumen may be set by moving the limiter to a corresponding marking on the second segment. This may be helpful in setting the desired range of motion because otherwise it may be difficult for a user to determine the exact position of the radiating tip portion. For example, the marking may indicate the length of the radiating tip portion protruding from the catheter when the third segment abuts the limiter.

[0057] In some embodiments, the first segment may include a second set of markings arranged to indicate the length of the catheter in the instrument channel based on the position of the second segment relative to the second set of markings. In this way, the user can adjust the length of the catheter by moving the second segment to a corresponding mark on the first segment. This can be helpful in adjusting the length of the catheter to a desired length, as it may otherwise be difficult to determine the length of the catheter when the catheter is in the instrument channel.

[0058] In some embodiments, the first section and the second section are telescopically arranged, and the second section can slide along the length of the first section. For example, the first section and the second section can have tubular concentric bodies, wherein one section is arranged to slide into the other section. In some cases, the second section and the third section are telescopically arranged, and the third section can slide along the length of the second section. For example, the first section and the second section can have tubular concentric bodies, wherein one section is arranged to slide into the other section. The telescopic configuration can provide a compact design of the handpiece.

[0059] The electrosurgical instruments and handpieces discussed above may form part of a complete electrosurgical system. For example, the electrosurgical system may include: an electrosurgical generator arranged to supply microwave energy and / or radiofrequency energy; a surgical scope having a flexible insertion cord for insertion into a patient, wherein the flexible insertion cord has an instrument channel extending along its length; an electrosurgical instrument according to the first aspect of the invention, wherein the electrosurgical instrument is sized to fit within the instrument channel; and a handpiece according to the second aspect of the invention, wherein the proximal end of the conduit of the electrosurgical instrument is retained in a holder, the proximal end of the coaxial cable of the electrosurgical instrument is received in the coaxial connector, and the coaxial connector is connected to the electrosurgical generator to receive the microwave energy and / or radiofrequency energy.

[0060] The term "surgical viewing device" may be used herein to refer to any surgical device having an insertion tube, which is a rigid or flexible (e.g., steerable) catheter introduced into a patient during an invasive procedure. The insertion tube may include an instrument channel and an optical channel (e.g., for transmitting light to illuminate and / or capture an image of the treatment site at the distal end of the insertion tube. The instrument channel may have a diameter suitable for receiving an invasive surgical tool. The diameter of the instrument channel may be 5 mm or less. In an embodiment of the present invention, the surgical viewing device may be an ultrasound-enabled endoscope.

[0061] Herein, the term "inner" means radially closer to the center (eg, axis) of the instrument channel and / or coaxial cable. The term "outer" means radially farther from the center (axis) of the instrument channel and / or coaxial cable.

[0062] Unless the context indicates otherwise, the term "conductive" is used herein to mean conductive.

[0063] In this document, the terms "proximal" and "distal" refer to the ends of the elongated probe. In use, the proximal end is closer to a generator for providing RF and / or microwave energy, while the distal end is farther away from the generator.

[0064] In this specification, "microwave" may be used broadly to indicate a frequency range of 400 MHz to 100 GHz, but preferably in the range of 1 GHz to 60 GHz. Preferred spot frequencies for microwave EM energy include: 915 MHz, 2.45 GHz, 3.3 GHz, 5.8 GHz, 10 GHz, 14.5 GHz, and 24 GHz. 5.8 GHz may be preferred. The device may deliver energy at more than one of these microwave frequencies.

[0065] The term "radio frequency" or "RF" may be used to indicate frequencies between 300 kHz and 400 MHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Embodiments of the present invention are discussed below with reference to the accompanying drawings, in which:

[0067] Figure 1 is a schematic diagram of an electrosurgical system as an embodiment of the present invention;

[0068] Figure 2a and Figure 2b A schematic cross-sectional view of an electrosurgical instrument as an embodiment of the present invention is shown, wherein Figure 2a The electrosurgical device of the instrument is in a retracted position and Figure 2b The electrosurgical device of the instrument is in a deployed position;

[0069] Figure 3a yes Figure 2a and Figure 2b A perspective view of an electrosurgical instrument;

[0070] Figure 3b yes Figure 2a and Figure 2b A perspective view of an electrosurgical instrument of , wherein a guide tube of the instrument is omitted to reveal the internal structure of the instrument;

[0071] Figure 4 yes Figure 2a and Figure 2b A perspective view of an electrosurgical instrument;

[0072] Figure 5 and Figure 6 is a schematic side view of an electrosurgical device as part of an electrosurgical instrument of an embodiment of the present invention;

[0073] Figure 7 A schematic cross-sectional view showing a distal needle tip of an electrosurgical instrument as an embodiment of the present invention;

[0074] Figure 8 A schematic diagram showing a distal needle tip of an electrosurgical instrument as an embodiment of the present invention;

[0075] Figure 9a and Figure 9b is a schematic cross-sectional view depicting deformation of a corresponding example of an electrosurgical instrument when inserted through an instrument channel in reflexion;

[0076] Fig.10 is a schematic cross-sectional view of a handpiece as an embodiment of the present invention;

[0077] Fig.11 and Fig.12 Show Fig.10 A perspective view of a handpiece, wherein the Fig.11 Parts of the components of the handpiece have been omitted to reveal the internal structure of the handpiece;

[0078] Fig.13a and Fig.13b Show Fig.10 A plan view of a handpiece of , wherein the distal needle is in a retracted and extended (deployed) position, respectively;

[0079] Fig.14a is a cross-sectional view of a catheter that is part of an electrosurgical instrument of an embodiment of the present invention; and

[0080] Fig.14b A cross-sectional view of a catheter that is part of an electrosurgical instrument of another embodiment of the present invention is shown.

[0081] Specific implementation method; other options and preferences

[0082] Figure 1 Schematic diagram of an electrosurgical ablation device 100 capable of supplying microwave energy and / or radiofrequency energy to the distal end of an invasive electrosurgical instrument. The system 100 includes a generator 102 for controllably supplying microwave energy and radiofrequency energy. Suitable generators for this purpose are described in WO 2012 / 076844, which is incorporated herein by reference. The generator may be arranged to monitor the reflected signal received back from the instrument to determine the appropriate power level for delivery. For example, the generator may be arranged to calculate the impedance observed at the distal end of the instrument to determine the optimal delivery power level.

[0083] The generator 102 is connected to the handpiece 106 via an interface cable 104. In other examples (not shown), the handpiece 106 may also be connected to a fluid delivery device such as a syringe via a fluid flow line, for example, where it is desired to deliver fluid to the distal end of the electrosurgical instrument.

[0084] The handpiece 106 houses an instrument control mechanism that is operable to control the longitudinal (back and forth) movement of the electrosurgical instrument. If necessary, the handpiece 106 may also house a control mechanism (e.g., a trigger) for actuating one or more control wires or push rods. Figures 10 to 12 An exemplary handpiece is described in more detail. The function of the handpiece is to combine the input from the generator 102 and any other input into an integrated flexible instrument cable that extends from the distal end of the handpiece 106 and is sized to be transmitted through an instrument channel of a surgical scope.

[0085] The handpiece 106 is connected to an input port 128 of a surgical viewing device 114. The surgical viewing device 114 includes a body 116 having a plurality of input ports and an output port from which an instrument cord 120 extends. The instrument cord 120 includes an outer sheath surrounding a plurality of lumens. The plurality of lumens transmit various things from the body 116 to the distal end of the instrument cord 120. One of the plurality of lumens is an instrument channel through which the instrument cable extends. Other lumens may include channels for transmitting optical radiation, for example, channels for providing illumination at the distal end or collecting images from the distal end, and ultrasound signal channels for transmitting ultrasound signals. The body 116 may include an eyepiece 122 or other imaging device capable of observing the distal end.

[0086] Endoscopic ultrasound devices typically include an ultrasound transducer at the distal tip of the instrument cord beyond the exit hole of the ultrasound signal channel. The signal from the ultrasound transducer can be transmitted along the instrument cord by a suitable cable 126 back to the processor 124, which can generate an image in a known manner. The instrument channel can be formed within the instrument cord to guide an instrument that exits the instrument channel through the field of view of the ultrasound system, thereby providing information about the position of the instrument at the target site.

[0087] The integrated flexible instrument cable extends from the distal end of the handpiece 106 and is received in an instrument channel in the instrument cord 120 of the surgical scope 114. The integrated flexible instrument cable has a distal assembly 118 (at Figure 1 ), the distal assembly 118 is shaped to pass through an instrument channel of the surgical peep device 114 and protrude at the distal end of the instrument cord 120 (eg, within a patient's body).

[0088] The structure of the distal assembly 118 discussed below can be specifically designed for use with an endoscopic ultrasound (EUS) device, wherein the maximum outer diameter of the distal end assembly 118 is equal to or less than 1.2 mm (e.g., less than 1.0 mm) and the length of the electrosurgical instrument can be equal to or greater than 1.2 m.

[0089] It may be desirable to be able to control the position of at least the distal end of the instrument cord 120. The body 116 may include a control actuator that is mechanically coupled to the distal end of the instrument cord 120 by one or more control wires (not shown) extending through the instrument cord 120. The control wires may travel within the instrument channel or within their own dedicated channel. The control actuator may be a lever or a rotatable knob, or any other known catheter manipulation device. Manipulation of the instrument cord 120 may be software-assisted, for example, using a virtual three-dimensional map assembled from a computed tomography (CT) image.

[0090] Figure 2a , Figure 2b , Figure 3a , Figure 3b and Figure 4 An electrosurgical instrument 200 is shown in accordance with an embodiment of the present invention. The electrosurgical instrument 200 includes an integrated instrument cable including an electrosurgical device 202 disposed in a catheter 204. The catheter 204 defines a lumen in which the electrosurgical device 202 is received and along which the electrosurgical device 202 is movable. The electrosurgical device 202 is movable along the catheter in a retracted position ( Figure 2a shown) and deployment location ( Figure 2b shown). Figure 2a and Figure 2b shows a schematic cross-sectional side view of an electrosurgical instrument 200; Figure 3a shows a perspective view of the instrument 200, wherein for illustrative purposes, the catheter 204 is shown as transparent to reveal the electrosurgical device 202 inside the catheter 204; and Figure 3b A perspective view of the instrument 200 is shown with the catheter 204 omitted for purposes of illustration. Figure 4 A perspective view of an electrosurgical instrument is shown with electrosurgical device 202 in a deployed position.

[0091] The electrosurgical device 202 is Figure 5 and Figure 6 206 and 208. The electrosurgical device 202 includes a flexible coaxial cable 206 and a radiating tip portion 208 connected at the distal end of the coaxial cable 206. The coaxial cable 206 may be a conventional flexible 50Ω coaxial cable suitable for transmitting microwave and radio frequency energy. The coaxial cable includes a center conductor and an outer conductor separated by a dielectric material. The coaxial cable 206 may be connected to a generator (e.g., the generator 102) at a proximal end to receive microwave and / or radio frequency energy.

[0092] The radiating tip portion 208 includes a proximal coaxial transmission line 210 and a distal needle tip 212 formed at the distal end of the proximal coaxial transmission line 210. The proximal coaxial transmission line 210 is electrically connected to the distal end of the coaxial cable 206 to receive electromagnetic energy from the coaxial cable 206 and transmit it to the distal needle tip 212. The distal needle tip 212 is configured to deliver the received electromagnetic energy into the target biological tissue. In the example shown, the distal needle tip 212 is configured as a half-wavelength transformer to deliver microwave energy into the target biological tissue to ablate the target tissue.

[0093] The inner conductor 214 of the proximal coaxial transmission line 210 is electrically connected to the center conductor of the coaxial cable 206. The radiating tip portion 208 is fastened to the coaxial cable 206 by a ferrule 216 installed over the joint between the coaxial cable 206 and the radiating tip portion 208. The ferrule 216 is made of a conductive material (e.g., brass) and electrically connects the outer conductor of the coaxial cable 206 to the outer conductor 218 of the proximal coaxial transmission line 210. The outer conductor 218 is formed of a nickel-titanium alloy tube.

[0094] The collar 216 includes a substantially cylindrical body 219 that is mounted on the distal end of the coaxial cable 206 and electrically connected to the outer conductor of the coaxial cable 206. The collar 216 also includes a distal portion 220 that extends from the body 219 of the collar 216 to the proximal end of the outer conductor 218 of the proximal coaxial transmission line 210. The distal portion 220 of the collar 216 includes a rounded distal surface. By avoiding sharp edges at the interface between the coaxial cable 206 and the radiating tip portion 208, this can reduce friction between the electrosurgical device 202 and the catheter 204 when the electrosurgical device 202 moves along the catheter 204. This can also facilitate movement of the electrosurgical device 202 along the catheter 204 when the catheter 204 is in a reflexed state.

[0095] The radiating tip portion 208 has a smaller outer diameter than the coaxial cable 206. This can make the radiating tip portion 208 more flexible than the coaxial cable 206, which can facilitate bending of the radiating tip portion 208 and / or guiding the radiating tip portion to a difficult treatment site. Making the outer diameter of the radiating tip portion 208 smaller can also reduce the size of the insertion hole formed when the radiating tip portion 208 is inserted into the tissue, which can minimize bleeding and facilitate healing. Preferably, the radiating tip portion can have an outer diameter of 1.2 mm or less, for example, 1.0 mm or 0.9 mm. The coaxial cable 206 can have an outer diameter of about 2.0 mm.

[0096] The catheter 204 is a flexible tube made of an insulating material (e.g., PEEK or PTFE). The catheter 204 is sized to be inserted into a working channel of a surgical peep instrument. The catheter 204 defines a lumen in which the electrosurgical device 202 is received and along which the electrosurgical device 202 can move.

[0097] The plug 222 is mounted at the distal end of the catheter 204. The plug 222 has a body portion 224, which is disposed inside the distal end of the catheter 204. The body portion 224 includes a barb (or protrusion) 226 disposed on the outer surface of the body portion 224, and the barb (or protrusion) 226 forms an interference fit with the catheter 204 so as to fasten the plug 222 at the distal end of the catheter 204. In this way, the plug 222 can be fastened at the distal end of the catheter 204 without using an adhesive (although an adhesive can be used to further fasten the plug 222 to the catheter 204). The distal surface 228 of the plug 222 (i.e., the surface exposed at the distal end of the catheter 204) is rounded. The rounded distal surface 228 of the plug 222 is used to avoid sharp edges around the distal end of the catheter 204. This may facilitate insertion of the electrosurgical device 200 along the instrument channel of the surgical scope by reducing friction between the catheter 204 and the instrument channel at the distal end of the catheter 204. The plug may be made of PEEK or some other insulating material.

[0098] The plug 222 has a longitudinal passage 230 defined therethrough. The passage 230 is sized to allow the radiating tip portion 208 to pass therethrough, but to prevent the coaxial cable 206 from passing therethrough. In this manner, the electrosurgical device 202 can be advanced along the catheter 204 such that the radiating tip portion 208 passes through the passage such that the length of the radiating tip portion 208 protrudes beyond the distal end of the catheter 204 (e.g., as shown in FIG. 1 ). Figure 2b shown).

[0099] The passage 230 includes a proximal opening 232 located within the catheter 204 at the proximal end of the body portion 224. The distal opening 234 of the passage 230 is located in the distal surface 228 of the plug 222. When the electrosurgical device 202 is in the deployed position (e.g., Figure 2b ), the radiating tip portion 208 protrudes through the distal opening 234 of the passage 230. The length of the passage 230 is greater than the length of the distal needle tip 212, that is, the distance between the proximal opening 232 and the distal opening 234 of the passage 230 is greater than the length of the distal needle tip 212. In this way, as Figure 2a As shown, when the electrosurgical device 202 is in the retracted position, the distal needle tip 212 can be completely contained within the passage 230 in the plug 222. In particular, when the electrosurgical device 202 is in the retracted position, the lip 236 formed by the distal end of the outer conductor 218 can be located inside the passage 230. This can prevent the lip 236 from getting stuck on the proximal opening 232 of the passage 230 when the electrosurgical device 202 moves from the retracted position to the deployed position.

[0100] The lip 236 of the outer conductor 218 is chamfered (e.g., beveled) to further prevent the lip 236 from getting stuck on the proximal opening 232 of the passage 230. The proximal opening 232 of the passage flares outward, i.e., the diameter of the opening 232 increases in the proximal direction. In this way, the flared proximal opening 232 is used to guide the radiating tip portion 208 into the passage to avoid the radiating tip portion 208 getting stuck on the proximal opening 232 and to facilitate the movement of the radiating tip portion 208 through the passage 230.

[0101] Passageway 230 is used to guide radiating tip portion 208 as electrosurgical device 202 moves between the retracted position and the deployed position. Passageway 230 is centered about the longitudinal axis of catheter 204 so that passageway 230 serves to focus radiating tip portion 208 as it moves through passageway 230.

[0102] exist Figure 2a 2, the electrosurgical device 202 is in a retracted position, wherein the distal needle tip 212 is located within the passage 230 in the plug 222. This means that the radiating tip portion 208 does not protrude from the catheter 204. Thus, in this configuration, the radiating tip portion 208 is protected by the catheter 204 and the plug 222. The electrosurgical instrument 200 can be inserted into the instrument channel of the surgical viewing device and guided into position with the electrosurgical instrument 202 in the retracted position. This can facilitate the insertion of the electrosurgical instrument 200 into the instrument channel, as it prevents the radiating tip portion 208 from getting stuck in the instrument channel.

[0103] Once the electrosurgical instrument 200 has been guided to the desired position, the electrosurgical device 202 may be moved into the deployed position. Figure 2a The retracted position shown may be achieved by moving the electrosurgical device 202 in a distal direction along the catheter 204 so that the radiating tip portion 208 protrudes through the distal opening 234 of the passage 230 in the plug 222. The electrosurgical device 202 may be moved until it reaches the Figure 2b When the electrosurgical device 202 protrudes from the distal opening 234 of the passage 230, the radiating tip portion 208 can be inserted into biological tissue. Once the distal needle tip 212 reaches the target treatment site (e.g., a tumor), microwave energy can be delivered to the distal needle tip to ablate the target tissue.

[0104] Once the target tissue has been treated, the electrosurgical device 202 may be moved back to the retracted position so that the radiating tip portion 208 is no longer exposed. This is accomplished by moving the electrosurgical device 202 along the catheter 204 in a proximal direction.

[0105] A sharp lip 238 is disposed around the distal opening 234 of the passageway 230. When the electrosurgical device 202 is moved from the deployed position to the retracted position, the sharp lip 238 is used to scrape any tissue or blood adhered to the radiating tip portion 208. This prevents tissue and / or blood from being dragged into the catheter 204 when the radiating tip portion 208 is pulled back into the catheter 204, which could contaminate the catheter 204 or impede movement of the electrosurgical device 202 within the catheter.

[0106] Now refer to Figure 5 and Figure 6 The structure of the radiating tip portion 208 of the electrosurgical device 202 is described in more detail. Figure 6 The outer conductor 218 is omitted in order to expose the inner structure of the radiating tip portion 208. Also for the purpose of illustration, Figure 5 and Figure 6 A section of the proximal coaxial transmission line 210 has been omitted in FIG. 5 , as indicated by dashed line 502 .

[0107] The proximal coaxial transmission line 210 includes a proximal dielectric sleeve 504 disposed around the inner conductor 214. The outer conductor 218 is formed on the outer surface of the proximal dielectric sleeve 504. The distal dielectric sleeve 506 is disposed around the distal portion of the inner conductor 214 to form the distal needle tip 212. The distal dielectric sleeve 506 is made of a different dielectric material than the proximal dielectric sleeve 504. In one example, the proximal dielectric sleeve 504 can be made of PTFE (for example, it can be a PTFE tube), and the distal dielectric sleeve can be made of PEEK. The distal portion of the outer conductor 218 overlies the proximal portion of the distal dielectric sleeve 506. In this way, the distal portion of the proximal coaxial transmission line 210 includes the proximal portion of the distal dielectric sleeve 506. The materials of the proximal and distal dielectric sleeves and the overlap length between the outer conductor 518 and the distal dielectric sleeve 506 may be selected to adjust the electrical length of the radiating tip portion 208 to assist in impedance matching with the target tissue.

[0108] The outer conductor 218 may be made of a nickel-titanium alloy that is flexible and provides sufficient longitudinal stiffness to penetrate tissue (e.g., the duodenal wall). The inner conductor is made of a stainless steel core coated with a silver coating. The stainless steel core provides additional stiffness to the radiating tip portion 208, while the silver coating may increase the conductivity of the inner conductor 214 to reduce losses in the radiating tip portion 208.

[0109] The dielectric spacer 508 is installed at the joint between the radiating tip portion 208 and the coaxial cable 206. The dielectric spacer 508 is disposed inside the collar 216 and is installed around the inner conductor 214. In this way, the dielectric spacer 508 is disposed between the inner conductor 214 and the collar 216. This can increase the breakdown distance between the inner conductor 214 and the collar 216 at the joint between the coaxial cable 206 and the radiating tip portion 208. This can improve the electrical safety of the device at the joint. The dielectric spacer 508 can be, for example, a PTFE gasket or a gasket made of another suitable insulating material.

[0110] As mentioned above, the distal needle tip 212 is configured as a half-wavelength converter for delivering microwave energy into tissue. Therefore, when microwave energy is delivered to the distal needle tip 212, the distal needle tip 212 can radiate microwave energy into the surrounding tissue. The distal needle tip 212 includes a pointed tip 510 at its distal end to facilitate insertion of the radiating tip portion 208 into the target tissue. The pointed tip 510 is made of a dielectric material having a higher rigidity than the distal dielectric sleeve 506. This can make the pointed tip 510 sharper and can facilitate sharpening of the pointed tip 510. For example, the pointed tip 510 can be made of zirconium oxide.

[0111] Figure 7 A more detailed view of the pointed tip 510 mounted at the distal end of the distal dielectric sleeve 506 is shown. The pointed tip 510 includes a tapered portion 702 that tapers to a fine point and is used to pierce tissue. The pointed tip also includes a body 704 that extends from the proximal end of the tapered portion 702 and is received in the hole at the distal end of the distal dielectric sleeve. The body 704 of the pointed tip 510 includes a protrusion (or protrusion) 706 that forms an interference fit with the wall of the hole so as to keep the body 704 in the hole. In this way, when the body 704 is inserted into the hole, a "push fit" connection can be formed. This can enable the pointed tip 510 to be installed in the distal dielectric sleeve 506 without adhesive. This can also facilitate the replacement of the pointed tip 510, for example, when the pointed tip 510 is damaged.

[0112] Figure 8An example of a different pointed tip 802 mounted at the distal end of the distal dielectric sleeve 506 is shown. The pointed tip 802 includes a body 804 disposed in a hole at the distal end of the distal dielectric sleeve 506. The body 804 includes a protrusion 806 for fastening the body 804 in the hole. The pointed tip 802 also includes a tapered portion 808 that protrudes from the hole in the distal dielectric sleeve 506 and tapers to a fine point for piercing tissue. The tapered portion 808 includes a proximal portion 810 that tapers at a first angle relative to the longitudinal direction, and a distal portion 812 that tapers at a second, greater angle relative to the longitudinal direction. In this manner, the pointed tip 802 can be said to be "double-angled". The fine point of the pointed tip 802 is formed by the distal portion 812. By making the taper angle of the distal portion 812 greater than the taper angle of the proximal portion 810, the length of the tapered portion 808 can be reduced. This may make the pointed tip 802 less fragile and reduce the risk of the fine point of the pointed tip 802 breaking off.

[0113] In some embodiments (not shown), the pointed tip may be made of the same material as the distal dielectric sleeve, for example, the pointed tip may be integrally formed with the distal dielectric sleeve. The concept of using a double-angled pointed tip may be applied regardless of whether the pointed tip is integrally formed with the distal dielectric sleeve or formed separately from the distal dielectric sleeve. In some embodiments (not shown), a single dielectric sleeve may be provided in place of the proximal and distal dielectric sleeves, for example, the dielectric material in the proximal coaxial transmission line and the distal needle tip may be the same.

[0114] Figure 9a A cross-sectional view of an electrosurgical instrument 900 is shown with a distal portion of the instrument 900 in reflexion, in accordance with an embodiment of the present invention. Figure 9b A cross-sectional view of an electrosurgical instrument 902 is shown with a distal portion of the instrument 902 in reflexion, according to another embodiment of the present invention.

[0115] Electrosurgical instruments 900 and 902 have a similar configuration as electrosurgical instrument 200 described above. Electrosurgical instrument 900 includes a catheter 904 in which an electrosurgical device 906 is disposed. Electrosurgical device 906 includes a coaxial cable 908 having a radiating tip portion 910 disposed at a distal end of coaxial cable 908. Electrosurgical device 906 is movable along catheter 904 between a retracted position in which radiating tip portion 910 is located within catheter 904 and a deployed position in which radiating tip portion 910 protrudes from the distal end of catheter 904. Figure 9a In the illustrated configuration, electrosurgical device 906 is in a deployed position.

[0116] Similarly, electrosurgical instrument 902 includes an electrosurgical device 912 disposed in a catheter 914. Electrosurgical device 912 includes a coaxial cable 916 and a radiating tip portion 918 located at the distal end of coaxial cable 916. Electrosurgical device 912 is movable along catheter 914 between a retracted position in which radiating tip portion 918 is located within catheter 914 and a deployed position in which radiating tip portion 918 protrudes from the distal end of catheter 914. Figure 9b In the illustrated configuration, electrosurgical device 912 is in a deployed position.

[0117] exist Figure 9a In the embodiment, the distal portion 920 of the catheter 904 is in a backward flexion, that is, the distal portion 920 of the catheter 904 is curved. Figure 9a It can be seen that the distal portion of the coaxial cable 908 is located in the distal portion 920 of the catheter 904 and is also curved. Therefore, in order to move the electrosurgical device 906 between the retracted position and the deployed position ( Figure 9a 920 of the catheter 904), it is necessary to bend the distal portion of the coaxial cable 908. For example, when the electrosurgical device 906 is moved from the retracted position to the deployed position, the distal portion of the coaxial cable 908 must be pushed through the curved distal portion 920 of the catheter 904. When the electrosurgical device 906 is moved from the deployed position to the retracted position, the distal portion of the coaxial cable 908 must be unbent when being pulled out of the curved distal portion 920 of the catheter 904.

[0118] Due to the stiffness of the coaxial cable 908, bending and straightening of the coaxial cable 908 may require a large force. Coaxial cables conventionally used in electrosurgical devices, such as Sucoform 86 coaxial cables, have a relatively stiff (e.g., heavily tinned) outer sheath. Although such an outer sheath may facilitate actuation of the device along a straight path, a large force may be required to bend the cable. Therefore, when the distal portion of the catheter 904 is in flexion, it may be necessary to apply a large force to the electrosurgical device 906 in order to move it between the retracted position and the deployed position. This may result in a large amount of friction between the coaxial cable 908 and the curved portion 920 of the catheter 904, which may reduce the accuracy with which the position of the radiating tip portion 910 can be controlled.

[0119] The radiating tip portion 918 ( Figure 9b ) than the radiating tip portion 910 of the electrosurgical device 906 ( Figure 9a ) is longer. Thus, when the distal portion 922 of the catheter 914 is bent (e.g., Figure 9b914 ), it may not be necessary to move the coaxial cable 916 through the curved portion 922 of the catheter 914 when the electrosurgical device 906 is moved to the deployed position. The radiating tip portion 918 may be more flexible than the coaxial cable 916 because the radiating tip portion 918 has a smaller diameter than the coaxial cable and does not have a rigid outer sheath. Therefore, when the radiating tip portion 918 is moved through the curved distal portion 922 of the catheter 914, only a relatively small force may be required to bend the radiating tip portion 918.

[0120] like Figure 9b As shown, by making the radiating tip portion 918 long enough, when the electrosurgical device 912 is in the deployed position, the distal end of the coaxial cable 916 does not enter the curved distal portion 922 of the catheter 914, so that when the electrosurgical device 912 is moved between the retracted position and the deployed position, the distal end of the coaxial cable 916 does not need to be bent. Preferably, the radiating tip portion can be 140 mm or longer. This ensures that when the electrosurgical device 912 is in the deployed position, the coaxial cable 916 does not enter the back-bend portion of the catheter 914.

[0121] Thus, as the electrosurgical device 912 moves along the guide tube 914, Figure 9b The configuration shown can reduce friction between the electrosurgical device 912 and the catheter 914. This can improve control over the position of the radiating tip portion 918.

[0122] The electrosurgical device 912 also includes an outer sheath 924 disposed around the proximal portion of the radiation tip portion 918. The outer sheath 924 is made of or coated with a non-adhesive material, for example, the outer sheath 924 may be a PTFE tube. The outer sheath 924 may be used to reduce friction between the radiation tip portion 918 and the curved distal portion 922 of the catheter 914. This may be beneficial in moving the electrosurgical device 912 between the retracted position and the deployed position. The outer sheath 924 may also reduce lateral movement of the radiation tip portion 918 within the catheter by acting as a spacer between the radiation tip portion 918 and the catheter 914. This may be beneficial in moving the radiation tip portion along the curved distal portion 922 of the catheter 914.

[0123] Fig.10 A cross-sectional view of a handpiece 1000 is shown in accordance with an embodiment of the present invention. A perspective view of the handpiece 1000 is shown in Fig.11 , where portions of the components of the handpiece 1000 have been removed to reveal the internal structure of the handpiece 1000. Additional perspective views of the handpiece 1000 are shown in Fig.12Handpiece 1000 may be used with an electrosurgical instrument of the present invention (eg, electrosurgical instruments 200, 900, 902) to move an electrosurgical device of the instrument along a guide tube of the instrument between a retracted position and a deployed position.

[0124] The handpiece 1000 includes a first section 1002 having a generally cylindrical hollow body 1004. A connector 1006 is provided at the distal end of the hollow body 1004, the connector 1006 being adapted to mount the handpiece to an input port of an instrument channel of a surgical viewing device. The connector 1006 may be configured to mate with a corresponding connector on the input port. The connector 1006 may include a Luer fitting (or some other suitable fitting) to provide a leak-free connection between the handpiece 1000 and the instrument channel of the surgical viewing device.

[0125] The handpiece 1000 also includes a second section 1008. The second section 1008 is formed by a generally cylindrical hollow body 1010 telescopically mounted on the first section 1002 such that the second section 1008 can slide longitudinally over the length of the first section 1002. The second section 1008 includes a set screw 1012 for fixing the position of the second section 1010 relative to the first section 1002. The set screw 1012 engages in a threaded hole in the side wall of the hollow body 1010. Tightening the set screw 1012 in the threaded hole causes the set screw 1012 to engage the body 1004 of the first section 1002 to fix the position of the second section 1010 relative to the first section 1002. Loosening the set screw 1012 in the threaded hole disengages the set screw from the first section 1002 such that the second section 1008 can slide relative to the first section 1002.

[0126] The second section 1008 includes a retainer 1014 disposed on the interior of the body 1010 of the second section 1008. The retainer 1014 is configured to retain the proximal end of the catheter of the electrosurgical instrument. The retainer 1014 may, for example, be a clip or a clamp arranged to retain the proximal end of the catheter. In another example, the retainer 1014 may be a surface to which the proximal end of the catheter can be fastened (e.g., using an adhesive). In this way, when the proximal end of the catheter is retained in the retainer 1014, the position of the catheter is fixed relative to the second section 1008. Therefore, sliding the second section 1008 relative to the first section 1002 causes the catheter to move relative to the first section 1002.

[0127] The handpiece 1000 also includes a third section 1016. The third section 1016 is formed by a generally cylindrical hollow body 1018 telescopically mounted on the second section 1008 such that the third section 1016 can slide longitudinally over the length of the second section 1008. A coaxial connector 1020 is mounted on a proximal end 1019 of the body 1018. A proximal end 1022 of the coaxial connector 1020 is exposed outside the body 1018 of the third section 1016. The proximal end 1022 of the coaxial connector 1020 can be connected to an electrosurgical generator, for example, via a connecting cable (not shown).

[0128] The distal end 1024 of the coaxial connector 1020 is disposed within the hollow body 1018 of the third section 1016. The distal end 1024 of the coaxial connector 1020 is arranged to receive the proximal end of the coaxial cable of the electrosurgical device. For example, the distal end 1024 of the coaxial connector 1020 may include an inner conductor and an outer conductor, which may be electrically connected to the center conductor and the outer conductor of the coaxial cable, respectively (e.g., by soldering or welding). Alternatively, the distal end 1024 of the coaxial connector 1020 may be adapted to mate with a corresponding connector on the proximal end of the coaxial cable. The coaxial connector 1020 is arranged to transmit electromagnetic energy from a cable connected to its proximal end 1022 to a coaxial cable connected to its distal end 1024.

[0129] A slidable limiter 1026 is mounted on the outer surface of the body 1010 of the second segment 1008. The slidable limiter 1026 can slide along the outer surface of the body 1010 of the second segment 1008. The position of the slidable limiter 1026 can be fixed relative to the second segment 1008 by a fixing screw 1028, which is engaged in the threaded hole of the slidable limiter. The slidable limiter 1026 includes a stop surface 1030, which is arranged to abut against a distal surface 1029 of the body 1018 of the third segment 1016 when the third segment moves in the distal direction (i.e., toward the first segment 1002) to prevent further movement of the third segment 1016 in the distal direction. In this way, the range of motion of the third segment 1016 relative to the second segment 1008 can be adjusted by adjusting the position of the slidable limiter 1026 on the second segment 1008.

[0130] exist Fig.10 and Fig.11In the example shown, the proximal end of an electrosurgical instrument 1031 is mounted in the handpiece 1000. The electrosurgical instrument can be, for example, an electrosurgical instrument according to an embodiment of the present invention as described above. The proximal end of a guide tube 1032 of the instrument 1031 is held in a holder 1014 in the second section 1016 of the handpiece 1000. The proximal end of a coaxial cable 1034 of the instrument 1031 is electrically connected to a distal end 1024 of a coaxial connector 1020 in the third section 1016 of the handpiece 1000. The coaxial cable 1034 is disposed in the guide tube 1032 and can slide along the guide tube 1032. The electrosurgical instrument 1031 extends within the hollow bodies of the first section, the second section, and the third section of the handpiece 1000. The distal portion of the electrosurgical instrument 1031 extends from the handpiece through the connector 1006 at the distal end of the first section 1002.

[0131] The reinforcement tube 1036 is disposed around the outer surface of the proximal portion of the coaxial cable 1034. The reinforcement tube 1036 is fastened to the coaxial connector 1020. The reinforcement tube 1036 is made of a rigid material (e.g., a rigid metal or plastic). The reinforcement tube 1036 is used to increase the longitudinal rigidity of the proximal portion of the coaxial cable 1034 to facilitate the transmission of longitudinal forces to the coaxial cable 1034 when the third section 1016 moves relative to the second section 1008. The proximal portion 1038 of the catheter 1032 has an expanded diameter so that the proximal portion of the coaxial cable 1034 and the reinforcement tube 1036 can slide within the catheter 1032.

[0132] In use, the distal portion of the electrosurgical instrument 1031 extending from the connector 1006 can be inserted into the instrument channel of the surgical peep device. Then, the connector 1006 of the handpiece 1000 can be connected to the corresponding connector on the input port of the surgical peep device to fasten the handpiece 1000 to the surgical peep device. Subsequently, the length of the catheter 1032 in the instrument channel can be adjusted by sliding the second section 1008 relative to the first section 1002. Since the catheter 1032 is fixed relative to the second section 1008 (through the retainer 1014), moving the second section 1008 relative to the first section 1002 will change the length of the catheter 1032 extending from the connector 1006, and thus change the length of the catheter 1032 located in the instrument channel. A set of markings 1040 is provided on the outer surface of the body 1004 of the first section 1002. Each mark in the set of markings 1040 indicates the length of the catheter extending from the handpiece when the distal surface 1041 of the second section 1008 is aligned with the mark. Thus, the second section 1008 can be moved along the first section 1002 to a mark on the first section 1002 that corresponds to the desired length of the catheter 1032 in the instrument channel. When the desired length is achieved, the position of the second section 1008 can be fixed relative to the first section 1002 by tightening the set screw 1012.

[0133] After adjusting the length of the catheter 1032, the coaxial cable 1034 can be moved along the catheter 1032, for example, to expose or retract the radiating tip portion of the instrument 1031. The coaxial cable 1034 can be moved along the catheter 1032 by sliding the third section 1016 relative to the second section 1008. The longitudinal movement of the third section 1016 relative to the second section 1008 is transmitted to the distal end of the coaxial cable 1034, which is connected to the coaxial connector 1020 in the third section 1016. The reinforcing tube 1036 prevents the proximal end of the coaxial cable 1034 from bending, so that the longitudinal movement of the third section 1016 is transmitted to the coaxial cable 1034. When the third section 1016 moves in the proximal direction relative to the second section 1008, the reinforcing tube slides into the expanded proximal portion 1038 of the catheter 1032.

[0134] Since the guide tube 1032 is fixed relative to the second section 1008, sliding the third section 1016 relative to the second section 1008 causes the coaxial cable 1034 to slide within the guide tube 1032. Therefore, when the handpiece 1000 is used with the electrosurgical instrument of the present invention (e.g., electrosurgical instrument 200), the electrosurgical device can be moved between the retracted position and the deployed position by moving the third section 1016 forward and backward relative to the second section 1008. Specifically, the electrosurgical device can be moved to the deployed position by moving the third section 1016 in the proximal direction relative to the second section 1008, and can be moved to the retracted position by moving the third section 1016 in the distal direction relative to the second section 1008.

[0135] The user can adjust the position of the slidable limiter 1026 on the second section 1008 to set the maximum forward position of the third section 1016 relative to the second section 1008. This can set the maximum extension of the radiating tip portion beyond the distal end of the catheter 1032 when the electrosurgical device is in the deployed position. In this way, the slidable limiter 1026 can prevent the radiating tip portion from being pushed too far beyond the distal end of the catheter 1032. A set of markings 1042 is provided on the outer surface of the body 1010 of the second section 1008. Each mark in the set of markings 1042 indicates the maximum extension of the radiating tip portion beyond the distal end of the catheter 1032 when the slidable limiter 1026 is aligned with the mark and the distal surface 1029 of the third section 1016 abuts against the stop surface 1030 of the slidable limiter 1026. The slidable limiter 1026 can therefore be moved to a corresponding mark in the set of markings 1042 to set the desired maximum extension of the radiating tip portion.

[0136] Fig.13a and Fig.13b The operation of hand piece 1000 to move the electrosurgical device of instrument 1031 between a retracted position and a deployed position is shown. Fig.13a In the embodiment, the electrosurgical device of the instrument 1031 is in a retracted position, i.e., the radiating tip portion of the electrosurgical device does not protrude beyond the distal end 1044 of the catheter 1032. Fig.13b 1031, the electrosurgical device of the instrument 1031 is in a deployed position, i.e., the radiating tip portion 1046 of the electrosurgical device protrudes beyond the distal end 1044 of the catheter 1032. In this configuration, electromagnetic energy can be delivered to the radiating tip portion 1046 through the coaxial connector 1020 to deliver energy to the target tissue.

[0137] In order to Fig.13a The configuration shown goes to Fig.13bIn the configuration shown, first, the limiter 1026 can be moved to a desired position on the body 1010 of the second segment 1008. Next, the third segment 1016 can be slid over the second segment 1008 in the distal direction. The third segment 1016 can be advanced until the distal surface 1029 of the third segment 1016 abuts against the slidable limiter 1026, as shown in FIG. Fig.13b Once treatment of the target tissue is completed, the third segment 1016 can be returned to the proximal side by sliding it in the proximal direction relative to the second segment. Fig.13a The configuration shown is used to retract the radiating tip portion 1046 into the catheter 1032. For illustrative purposes, Fig.13a and Fig.13b The length of the instrument 1031 is omitted, as indicated by the dashed line 1048.

[0138] Fig.14a A cross-sectional view of a catheter 1400 that can be used as part of the electrosurgical instrument of the present invention is shown. The catheter 1400 defines a lumen 1402 extending therethrough and in which an electrosurgical device can be received. The catheter 1400 includes a proximal section 1404 having a first diameter 1406 and a distal section 1408 having a second, smaller diameter 1410. Exemplary sizes for the first and second diameters are 2.70 mm and 2.30 mm, respectively. A stepped section 1412 connects the proximal section 1404 and the distal section 1408. The larger diameter of the proximal section 1404 is arranged so that the proximal section 1404 can receive a proximal section of a coaxial cable of an electrosurgical device that includes a reinforcement element that increases the effective outer diameter of the proximal section of the coaxial cable.

[0139] Fig.14b A cross-sectional view of another catheter 1414 that can be used as part of the electrosurgical instrument of the present invention is shown. The catheter 1414 defines a lumen 1416 extending therethrough and in which an electrosurgical device can be received. The catheter 1414 includes a proximal section 1418 having a first diameter 1420 and an intermediate section 1422 having a second, smaller diameter 1424. The larger diameter of the proximal section 1404 is arranged so that the proximal section 1404 can receive a proximal section of a coaxial cable of the electrosurgical device including a reinforcement element. The proximal section 1418 and the intermediate section 1422 are connected by a step section 1426.

[0140] The tapered section 1428 is located at the distal end of the catheter 1414. The tapered section 1428 is used to reduce the diameter of the catheter 1414 at the distal end of the catheter from the second diameter 1424 to a third smaller diameter 1430. The tapered section 1428 defines a distal opening 1432 of the catheter 1414, the diameter of which is the third diameter 1430. The third diameter 1432 is set so that it is larger than the outer diameter of the radiating tip portion of the electrosurgical instrument and smaller than the outer diameter of the coaxial cable of the instrument. In this way, the radiating tip portion can protrude through the distal opening 1432 (for example, when the electrosurgical device is in the deployed position), but the coaxial cable (which has a larger outer diameter than the radiating tip portion) can be prevented from passing through the distal opening 1432. In this way, the tapered section 1428 can achieve a function similar to the plug 222 at the end of the catheter 204. By providing a tapered section 1428 at the distal end of the conduit 1414, it may not be necessary to provide a plug at the distal end of the conduit 1414. This may simplify the construction of the electrosurgical instrument. Exemplary sizes for the first diameter, the second diameter, and the third diameter are 2.70 mm, 2.30 mm, and 1.10 mm, respectively.

[0141] Different sections of the conduits 1400 and 1414 can be made by bonding together tubes of different diameters. Alternatively, the conduits 1400 and 1414 can be made from a single tube formed by a multi-diameter extrusion process. This can be done by extruding the tube to a first diameter and then post-processing a portion of the tube to re-mold the portion to a different (e.g., larger) diameter.

Claims

1. An electrosurgical instrument, comprising: a flexible catheter having a lumen extending therethrough, the catheter being sized to be inserted through an instrument channel of a surgical scoping device; as well as An electrosurgical device, the electrosurgical device is disposed in the lumen, the electrosurgical device comprising: a flexible coaxial cable configured to transmit microwave energy; and a radiation tip portion connected at a distal end of the coaxial cable to receive the microwave energy, the radiation tip portion having a smaller outer diameter than the flexible coaxial cable, wherein the radiation tip portion comprises: a proximal coaxial transmission line for transmitting the microwave energy; and a distal needle tip at a distal end of the proximal coaxial transmission line, the distal needle tip being configured to radiate the microwave energy into biological tissue, The electrosurgical device is longitudinally movable within the lumen between a deployed position in which the distal needle tip protrudes beyond the distal end of the catheter and a retracted position in which the distal needle tip is partially received within the catheter.

2. An electrosurgical instrument according to claim 1, wherein the distal needle tip is configured to operate as a half-wavelength transformer to deliver the microwave energy from the distal needle tip into biological tissue.

3. An electrosurgical instrument according to claim 1 or 2, wherein the guide tube includes a constricted passage at its distal end, the constricted passage being sized to allow the radiating tip portion to pass therethrough and to inhibit the flexible coaxial cable from passing therethrough.

4. An electrosurgical instrument according to claim 3, wherein the constriction passage extends through a plug mounted at the distal end of the conduit.

5. An electrosurgical instrument according to claim 1, wherein the distal surface of the guide tube is rounded.

6. An electrosurgical instrument as recited in claim 3, wherein said distal needle tip remains in said retracted passageway when in said retracted position.

7. An electrosurgical instrument as recited in claim 1, wherein the distal needle tip comprises a pointed tip at a distal end thereof.

8. An electrosurgical instrument according to claim 7, wherein the pointed tip is made of a rigid insulating material.

9. An electrosurgical instrument according to claim 7 or 8, wherein the distal needle tip comprises a distal dielectric sleeve surrounding a central conductive element, and wherein the pointed tip is secured in a hole at a distal end of the distal dielectric sleeve.

10. The electrosurgical instrument of claim 7, wherein the pointed tip is made of zirconium oxide.

11. An electrosurgical instrument according to claim 1, wherein the proximal coaxial transmission line includes an inner conductor separated from an outer conductor by a dielectric sleeve, wherein the inner conductor includes a distal portion that protrudes beyond the distal end of the outer conductor, and wherein the distal needle tip includes the length of the distal portion of the inner conductor.

12. An electrosurgical instrument as claimed in claim 11, wherein the outer conductor of the proximal coaxial transmission line is made of nickel titanium alloy.

13. An electrosurgical instrument according to claim 1, wherein the radiating tip portion is secured to the coaxial cable by a collar mounted over a junction between the radiating tip portion and the coaxial cable, the collar having a rounded distal surface.

14. An electrosurgical instrument according to claim 1, wherein the length of the radiating tip portion is equal to or greater than 140 mm.

15. The electrosurgical instrument of claim 1, wherein the radiating tip portion has a non-adhesive material on an outer surface thereof.

16. An electrosurgical instrument as recited in claim 1, wherein a proximal portion of the coaxial cable is secured to a rigid reinforcement element.

17. An electrosurgical instrument as recited in claim 16, wherein a proximal portion of the lumen has a larger diameter than a distal portion of the lumen to receive the proximal portion of the coaxial cable.

18. An electrosurgical instrument according to claim 1, wherein the inner conductor of the proximal coaxial transmission line is formed by an inner core and an outer conductive coating, wherein the inner core is made of a first conductive material and the outer conductive coating is made of a second conductive material having a higher conductivity than the first conductive material.

19. A handpiece for controlling movement of an electrosurgical instrument along a lumen of a catheter, the handpiece comprising: a first section having a connector for connecting a distal end of the handpiece to an instrument port of a surgical scoping device; a second section connected to the first section and movable along a length of the first section, the second section having a retainer for retaining a proximal end of the catheter, whereby relative movement between the second section and the first section is arranged to control the length of the catheter extending from the distal end of the handpiece; as well as A third section is connected to the second section and can move along the length of the second section, the third section has a coaxial connector, and the coaxial connector is arranged to receive the proximal end of the coaxial cable transmitted in the lumen of the catheter, whereby the relative movement between the third section and the second section is arranged to control the relative position of the coaxial cable in the catheter.

20. The handpiece of claim 19, wherein the second section has a fixing mechanism for fixing the position of the second section relative to the first section.

21. A handpiece according to claim 19 or 20, wherein the second section includes a limiter movable along the length of the second section, and wherein the limiter is arranged to constrain movement of the third section relative to the second section.

22. The handpiece of claim 19, wherein the first section and the second section are telescopically arranged, the second section being slidable along a length of the first section.

23. The handpiece of claim 19, wherein the second section and the third section are telescopically arranged, the third section being slidable along a length of the second section.

24. An electrosurgical system for treating biological tissue, the system comprising: an electrosurgical generator arranged to supply microwave energy; A surgical peep device having a flexible insertion cord for insertion into a patient, wherein the flexible insertion cord has an instrument channel extending along its length; An electrosurgical instrument according to any one of claims 1 to 18, wherein the electrosurgical instrument is sized to fit within the instrument channel; and A handpiece according to any one of claims 19 to 23, wherein the proximal end of the conduit of the electrosurgical instrument is retained in a holder, the proximal end of the coaxial cable of the electrosurgical instrument is received in the coaxial connector, and the coaxial connector is connected to the electrosurgical generator to receive the microwave energy.

Images