RU2779032C1 - Electrosurgical instrument - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: electrosurgical apparatus has an emitting tip for delivering electromagnetic energy to biological tissues and is located in a catheter. The electrosurgical apparatus is configured to move relative to the catheter between the working position, wherein the emitting part of the tip is extended, and the retracted position, wherein the emitting part is located inside the catheter. Thus, the emitting tip part can be retracted until use. This can facilitate the insertion of the apparatus through the instrument channel of the surgical vision apparatus. In particular, this can prevent the engagement of the emitting tip part of the instrument channel when the apparatus is inserted into the instrument channel, which can damage the instrument channel and/or the emitting tip part.

EFFECT: reduced risk of damaging the instrument channel and/or the emitting tip part when inserting the apparatus.

24 cl, 14 dwg

Description

FIELD OF THE INVENTION

The present invention relates to an electrosurgical instrument for delivering electromagnetic energy to biological tissues in order to ablate target tissues. In particular, the probe is adapted to be inserted through the channel of a surgical viewing device or catheter, which can be introduced into the treated area in a non-invasive manner. The probe may be configured to ablate tissue such as a tumor, cyst, or other lesion. The probe may be particularly suitable for treating the pancreas.

BACKGROUND OF THE INVENTION

Electromagnetic (EM) energy, and in particular microwave and radio frequency (RF) energy, has been found to have therapeutic efficacy in electrosurgery due to its ability to cut, coagulate, and ablate body tissue. Typically, a device for delivering EM energy to body tissues comprises a generator containing an EM energy source and an electrosurgical instrument connected to the generator to deliver energy to the tissues. Standard electrosurgical instruments in most cases are designed for percutaneous insertion into the patient's body. However, it can be difficult to percutaneously position an instrument in the body, for example, if the target area is in a moving lung or in a thin walled region of the gastrointestinal (GI) tract. Other electrosurgical instruments may be delivered to the target area using a surgical viewing device (eg, endoscope) which may be passed through channels in the body such as the airway or lumen of the esophagus or colon. This allows the use of minimally invasive treatments that can reduce patient mortality and reduce the incidence of intraoperative as well as postoperative complications.

A known method of treating tissue in the pancreas using radiofrequency ablation under endoscopic ultrasound guidance (Pai, M., et al., Endoscopic ultrasound guided radiofrequency ablation, for pancreatic cystic neoplasms and neuroendocrine tumors , World J Gastrointest Surg 2015 April 27; 7(4 ): 52-59). In this method, a conductive wire having a small diameter (eg 0.33 mm) is inserted through the working channel of an ultrasonic endoscope. RF power is applied to the wire along with an external grounded return electrode in contact with the patient's skin to coagulate tissues in the liver and pancreas. To ablate the lesions, it is necessary to apply power for 90-120 seconds and, in some cases, remove the wire and reposition it.

SUMMARY OF THE INVENTION

In its most general form, the present invention provides an electrosurgical device having a radiating tip portion for delivering electromagnetic energy to biological tissues, the electrosurgical device being located in a catheter. The electrosurgical device is configured to move relative to the catheter between the operating position, in which the radiating tip part is extended, and the retracted position, in which the radiating tip part is inside the catheter. Thus, the radiating tip portion can be retracted until it is to be used. This may facilitate insertion of the device through the instrument channel of the surgical viewing device. In particular, this can prevent the radiating tip portion of the instrument channel from getting caught when the device is inserted into the instrument channel, which may cause damage to the instrument channel and/or the radiant tip portion.

This configuration may be particularly advantageous when treating tumors in the pancreas since the device can be positioned adjacent to the wall of the duodenum with the radiating tip in a retracted position. The radiating tip can then be extended to pierce the duodenal wall and penetrate the pancreas where it can deliver electromagnetic energy to ablate target tissues. The emitting tip may be sized to fit into the pancreas to provide a fast and accurate alternative to known RF ablation techniques.

While the present invention may be particularly suitable for use in the pancreas, it may also be suitable for use in other hard-to-treat areas such as lungs, liver, and the like.

According to a first aspect of the present invention, an electrosurgical instrument is provided, comprising: a flexible catheter having a lumen extending through it, the catheter sized to be inserted through the instrument channel of a surgical viewing device; and an electrosurgical device located in the lumen, the electrosurgical device comprising: a flexible coaxial cable configured to transmit microwave energy; and a radiating tip attached to a distal end of the coaxial cable for receiving microwave energy, the radiating tip having a smaller outer diameter than the flexible coaxial cable, the radiating tip including: a proximal coaxial transmission line for transmitting microwave energy; and a distal needle tip at the distal end of the proximal coaxial transmission line, wherein the distal needle tip is configured to radiate microwave energy into biological tissues, the electrosurgical device being longitudinally movable in the lumen between an operating position in which the distal needle tip protrudes beyond the distal end catheter, and a retracted position in which a portion of the distal needle tip is in the catheter.

This configuration allows the radiating tip to be retracted into the catheter when not in use. Thus, the tool can be moved to a position in which the radiating tip is in a retracted position to facilitate the tool's maneuvering. Because the radiating tip has a smaller outside diameter than the coaxial cable, it becomes more likely to snag in the instrument channel of the surgical viewing device or with tissues. By holding the radiating tip portion in a retracted position while maneuvering the tool, such engagement of the radiating tip portion can be avoided.

The electrosurgical device can be moved along the lumen of the catheter using a suitable drive mechanism. When the electrosurgical device is in the operating position, the entire radiating tip portion or portion thereof may protrude beyond the distal end of the catheter. When the electrosurgical device is in the retracted position, the distal needle tip may be positioned within the catheter such that it does not protrude beyond the distal end of the catheter. The electrosurgical device can be moved distally to move it to the operating position, and the electrosurgical instrument can be moved proximally to move it to the retracted position.

The catheter may be made from a tube made from a flexible biocompatible material. For example, the catheter may be made of polyetheretherketone (PEEK) or PTFE tubing. As another example, the catheter may be made of a polyester blockamide material (eg Pebax®). The catheter may be made of or coated with a non-stick material (eg, PTFE) to prevent tissue from sticking to the catheter. For placement within the instrument channel of a surgical viewing device, the catheter may have an outer diameter equal to or less than 2.0 mm.

The lumen may be a longitudinal passage through the catheter. The lumen may be sized to receive and pass an electrosurgical device.

The flexible coaxial cable may be a conventional low loss coaxial cable that can be connected at the proximal end to an electrosurgical generator to receive microwave energy. A coaxial cable may have a center conductor separated from the outer conductor by a dielectric material. The coaxial cable may further comprise an outer protective sheath to insulate and protect the cable. In some examples, the protective sheath may be made of or coated with a non-stick 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 over the coaxial cable.

The proximal coaxial transmission line is connected to the distal end of the coaxial cable to receive microwave energy transmitted over the coaxial cable. The proximal coaxial transmission line may have an inner conductor that is electrically connected to the center conductor of the coaxial cable. The proximal coaxial transmission line may further have a proximal dielectric sleeve located 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.

The materials used in the proximal coaxial transmission line may be the same as or different from those used in the coaxial cable. The materials used in the proximal coaxial transmission line may be selected to provide the required 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 target tissues.

The dimensions of the components of the proximal coaxial transmission line can be chosen so that its impedance is identical to or close to the impedance of the flexible coaxial cable (for example, approximately 50 ohms). The inner conductor may be formed from a highly conductive material such as 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 can make it easier to bend the radiating tip portion.

The distal needle tip is formed at the distal end of the proximal coaxial transmission line. The distal needle tip may comprise a radiating structure that is configured to receive microwave energy from the proximal coaxial transmission line and deliver the energy to target tissues. The emitting structure may be selected based on the type of energy delivered and the desired processing mode. For example, the radiating structure may include a monopolar or bipolar microwave antenna for radiating microwave energy into surrounding tissues to perform tissue ablation. In other examples, the radiating structure may include a pair of RF electrodes that are designed to deliver RF energy to target tissues. In such examples, the coaxial cable is configured to deliver radio frequency (RF) energy to an electrosurgical device, which may be capable of performing ablation, coagulation, and/or resection using RF energy. In some examples, the radiating structure may be configured to emit both microwave and RF energy (either simultaneously or sequentially).

As mentioned above, the outer diameter of the radiating tip is smaller than the outer diameter of the coaxial cable. By using a smaller diameter radiating tip, the size of the entry hole formed when the radiating tip is inserted into target tissues can be reduced. This can reduce bleeding and speed up wound healing. For example, it can reduce the size of the insertion hole made in the wall of the duodenum when inserting the device into the pancreas. The present inventors have also found that this configuration is advantageous for treating tumors in the liver, where bleeding from the inlet can be a problem.

Further, by making the outer diameter of the radiating tip smaller than that of the coaxial cable, the radiating tip can be more flexible than the coaxial cable. This can make it easier to guide the distal needle tip to the desired location, for example if it is necessary to guide the device around a severe bend. The present invention thus strikes a balance between using a relatively large outer diameter coaxial cable to reduce the effect of heat loss and a relatively small diameter radiating tip to provide improved flexibility and reduce tissue damage during insertion.

The distal needle tip may be configured to operate as a half-wave transformer to deliver microwave energy from the distal needle tip to biological tissues. The advantage of making the distal needle tip as a half-wave transformer can be to minimize reflections at the interface between the components, for example, between the coaxial cable and the proximal coaxial transmission line, and between the proximal coaxial transmission line and the distal needle tip. The reflectance at the last contact surface is generally larger due to the large impedance difference. The half-wave configuration can minimize these reflections, whereby the coefficient of the contact surface between the proximal coaxial transmission line and tissues becomes the dominant reflectance. The impedance of the proximal coaxial transmission line can be chosen to be identical or close to the expected tissue impedance to ensure proper matching at the frequency of the microwave energy.

The catheter may include a restricted passage at its distal end, the restricted passage being sized to allow passage of the radiating tip portion and impede passage of the flexible coaxial cable. In one example, the restricted passage may pass through a plug placed at the distal end of the catheter. The plug may prevent tissue and/or fluid from entering the catheter from the treated area. Moreover, the restricted passage may assist in guiding the radiating tip portion as the device moves between the retracted position and the operating position. This may allow precise placement of the radiating tip portion, which may facilitate guiding the distal needle tip to the target area to be treated. The limited passage can be aligned with the longitudinal axis of the tool to center the radiating tip portion with respect to the longitudinal axis. The plug may be made of an insulating material (eg PEEK) to avoid a short circuit between the plug and the radiating tip.

The plug may cover the opening at the distal end of the catheter, for example it may be a cap at the distal end of the catheter. The restricted passage may be sized so that the radiating tip can pass through, but to prevent the passage of a larger diameter coaxial cable. Thus, the restricted passage may restrict movement of the electrosurgical device along the lumen in a distal direction. This may prevent the coaxial cable from being pushed past the distal end of the catheter, which may prevent damage due to the larger diameter of the coaxial cable.

In some embodiments, the limited passageway may include a lip for removing biological tissue from the radiating tip portion when the electrosurgical device is moved from an operating position to a retracted position. For example, the edge may be configured to scrape tissue from the radiating tip portion while retracting the radiant tip portion into the catheter. This may prevent tissue from entering the catheter that could contaminate the catheter or cause instrument failure (eg, limited movement of the electrosurgical device along the lumen). The rim may be located at the distal opening of the passage, for example, the rim may be located around the distal opening of the passage. Thus, tissue can be prevented from entering the passage. The edge may be a sharp edge around the opening of the passage.

The distal surface of the catheter may be rounded. For example, the distal end surface of the plug may be rounded, such as hemispherical or domed. The rounded surface avoids sharp edges around the distal end of the catheter. This may facilitate the insertion of the instrument through the working channel of the surgical viewing instrument. In particular, this can make it easier to move the tool through a bend in the working channel.

The distal needle tip can be held in the restricted passage in a retracted position. For example, the proximal orifice of the restricted passage may be located within the catheter, and the distance between the proximal orifice of the restricted passage and the distal opening of the restricted passage may be greater than the length of the distal needle tip. In other words, the length of the restricted passage may be greater than the length of the distal needle tip. Thus, the distal needle tip can be completely within the restricted passage when the radiating tip portion is in the retracted position. A limited passage may be formed in the main part of the plug, which is located in the distal section of the catheter.

The proximal coaxial transmission line may have a larger outer diameter than the distal needle tip, for example, due to the outer conductor of the proximal coaxial transmission line. As a result, an edge or step may be located on the contact surface between the distal needle tip and the proximal coaxial transmission line. By making the restricted passage longer than the distal needle tip, the lip on the interface between the distal needle tip and the proximal coaxial transmission line can be positioned within the restricted passage when the device is in the retracted position. Thus, the edge is prevented from snagging on the proximal orifice of the limited passage when the device is moved from the retracted position to the operating position.

The proximal opening of the passage in the plug may expand outwardly, for example, the diameter of the proximal opening may increase in the proximal direction. Thus, the proximal opening of the passage can act as a bell that guides the radiating tip into the passage. This may facilitate movement of the electrosurgical device along the lumen and may prevent the radiating tip portion from snagging on the proximal orifice of the passageway.

In some embodiments, the plug may include a body located inside the catheter, and the main part contains a protrusion for attaching the plug to the catheter. Thus, the plug can be installed at the distal end of the catheter without the use of adhesive. However, in some cases, adhesive may be used to further secure the plug to the catheter. The protrusion may, for example, be a bulge or spike that can be pressed outward against the catheter to hold the plug in place in the catheter. The plug can be installed at the distal end of the catheter by pushing the main part of the plug into the catheter. Thus, a "tight fit" connection can be formed between the plug and the distal end of the catheter.

The distal needle tip may include a pointed tip at its distal end. The pointed tip can be made from a rigid insulating material such as zirconia or ceramic. Zirconia is a rigid dielectric material that can be tapered to a sharp point and therefore may be particularly suitable for use as a pointed tip. The pointed tip can aid in tissue piercing to facilitate insertion of the radiating tip portion into target tissues.

The distal needle tip may comprise a distal dielectric sleeve around the central conductive member, and the pointed tip may be secured in an opening at the distal end of the distal dielectric sleeve. The pointed tip may include a body that is located at the distal end of the distal dielectric sleeve, and the main part of the pointed tip may include a protrusion for securing the body in the opening. Thus, the pointed tip can be held in the opening at the distal end of the distal dielectric sleeve. By placing the main portion of the pointed tip in the opening on the distal dielectric sleeve, the pointed tip can be firmly held in place. The protrusion may, for example, be a bulge or tenon that can be pressed outwardly against the wall of the opening to hold the body in place in the opening. The pointed tip can be positioned at the distal end of the distal dielectric sleeve by pushing the main portion of the distal tip into the opening. Thus, a "tight fit" connection can be formed between the pointed tip and the distal dielectric sleeve. This configuration may allow the tapered tip to be mounted on a distal dielectric sleeve without adhesive. However, in some cases, glue can be used to further secure the pointed tip in place.

The pointed tip may be made of a dielectric material having a higher rigidity than the distal dielectric sleeve. Due to this, the pointed tip can be sharper, which makes it easier to pierce tissue.

The proximal coaxial transmission line may comprise an inner conductor separated from the outer conductor by a dielectric sleeve, the inner conductor having a distal portion that protrudes beyond the distal end of the outer conductor, and the distal needle tip having the length of the distal portion of the inner conductor. The distal dielectric sleeve can thus be positioned around the inner conductor which forms the central conductive element mentioned above.

The distal dielectric sleeve may be made from the same material as the dielectric material in the proximal coaxial transmission line or from a different material. The distal dielectric sleeve may have a higher rigidity than the dielectric material of the proximal coaxial transmission line. Giving more rigidity to the distal dielectric sleeve can facilitate the insertion of the distal needle tip into target tissues, while having a less rigid proximal coaxial transmission line can make it easier to bend the radiating tip portion. This may allow the instrument to be guided through narrow and tortuous passages while still being able to be inserted into target tissues. For example, the dielectric material of the proximal coaxial transmission line may be made of a flexible dielectric material (eg, PTFE), and the distal dielectric sleeve may be made of, for example, ceramic, polyetheretherketone (PEEK), or glass-filled PEEK.

In some embodiments, the pointed tip may have a proximal portion that tapers at a first taper angle with respect to the longitudinal direction and a distal section that tapers at a second taper angle with respect to the longitudinal direction, the first taper angle being less than the second taper angle. Due to the greater taper angle in the distal section of the pointed tip, brittleness of the pointed tip can be reduced. This can reduce the chance that particles will break off from the pointed tip and remain in the body.

The outer conductor of the proximal coaxial transmission line may be made of nitinol. For example, the outer conductor may be made of nitinol tubing. The inventors of the present invention have found that nitinol exhibits sufficient longitudinal rigidity to transmit a force suitable for penetrating the duodenal wall. Additionally, due to the flexibility of the nitinol, bending of the radiating tip portion can be facilitated so that the instrument can be guided through narrow, curved passages. Making the outer guidewire from nitinol can thus simplify the use of the instrument for treating tumors in the pancreas.

The radiating tip portion may be attached to the coaxial cable by means of a sleeve mounted over the joint therebetween, the sleeve having a distal surface that is rounded. The sleeve may be located on the contact surface between the distal end of the coaxial cable and the proximal end of the proximal coaxial transmission line. The distal surface of the sleeve may be a forward facing surface of the sleeve, i. e. the surface that faces the distal end of the instrument. By providing a sleeve with a rounded distal surface, sharp edges on the contact surface between the coaxial cable and the proximal coaxial transmission line can be avoided. This can reduce friction between the electrosurgical device and the catheter as the electrosurgical device moves along the lumen. This may, for example, make it easier to move the electrosurgical device along the lumen when the instrument is bent backwards (eg, when a fold is provided in the catheter).

In some embodiments, the sleeve may be conductive and may electrically connect the outer conductor of the proximal coaxial transmission line to the outer conductor of the coaxial cable, and a dielectric separator may be installed at the junction between the radiating tip portion and the coaxial cable, the dielectric separator being located between the inner conductor of the proximal coaxial line transmission and bushing. For example, the dielectric spacer may be an insulating washer mounted on the contact surface and located around the proximal end of the inner conductor. This can reduce the risk of a short circuit at the contact surface between the coaxial cable and the radiating tip, as well as improve the electrical safety of the joint.

The length of the radiating tip portion may be equal to or greater than 140 mm. Coaxial cables commonly used in electrosurgical instruments (such as Sucoform 86 coaxial cable) often have a heavily tinned outer sheath to allow longitudinal movement of the cable. However, this causes the coaxial cable to become relatively rigid, so that a considerable force is required to bend the coaxial cable. This can result in a significant amount of friction when moving the device through the fold in the catheter, which can prevent precise control of the device. Having a long radiating tip can make it easier to bend the instrument near its distal end, since the radiating tip can be more flexible than coaxial cable. By making the radiating tip portion 140 mm or more in length, the need to move the coaxial cable through the fold of the distal portion of the catheter can be avoided. This may, for example, facilitate the use of the radiating tip portion where the distal portion of the catheter is bent backwards. This configuration may be particularly advantageous for use in the pancreas where it is desirable that the distal portion of the instrument be curved backwards.

The radiating tip portion may have a non-stick material on its outer surface. For example, an outer sheath may be positioned over the proximal portion of the radiating tip portion, the outer sheath being made of or lined with a non-stick material. This may facilitate movement of the electrosurgical device along the lumen by reducing friction between the lumen and the radiating handpiece. This configuration may be particularly advantageous in combination with a long radiating tip (eg, 140 mm or longer) as this can facilitate movement of the radiating tip through a distal catheter that is curved backwards. The outer sheath may also increase the effective outer diameter of the radiating tip, which may reduce lateral movement of the radiant tip in the lumen. This can improve the positioning accuracy of the emitting tip portion. In some cases, the outer jacket may extend over all or part of the coaxial cable to reduce friction between the coaxial cable and the lumen.

In some embodiments, the outer sheath may be made from PTFE. For example, the outer sheath may be a PTFE tube located around the proximal portion of the radiating tip portion.

The proximal part of the coaxial cable may be attached to a rigid reinforcing element. The reinforcing element can help increase the longitudinal stiffness of the proximal part of the coaxial cable. This may facilitate the application of a force (eg, a push force or a pull force) to the proximal end of the coaxial cable to move the electrosurgical device along the lumen. This can improve the control of the position of the electrosurgical device in the lumen. The reinforcing element may be located on the outer surface of the proximal part of the coaxial cable.

In some embodiments, the implementation of the reinforcing element may be a rigid tube located on the outer surface of the proximal part of the coaxial cable. A rigid tube may have a higher longitudinal rigidity than a coaxial cable. For example, the rigid tube may be a metal tube (eg, stainless steel).

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. The outer diameter of the proximal part of the coaxial cable may be larger than the outer diameter of the distal part of the coaxial cable due to the presence of the reinforcing element. The presence of a catheter with a larger diameter proximal part can allow the proximal part of the coaxial cable to slide within the catheter without additional friction caused by the presence of the reinforcing element.

In some embodiments, the catheter may comprise a conical portion at its distal end, and the conical portion may taper from a first diameter at its proximal end to a second, smaller diameter at its distal end, the second diameter being greater than the outer diameter of the radiating tip portion and less than the outer diameter. coaxial cable diameter. Thus, the conical portion may allow the radiating tip portion to pass so that the radiant tip portion can protrude beyond the distal end of the catheter. In contrast, the conical portion may be configured to prevent the coaxial cable (which has a larger diameter than the radiating tip portion) from being pushed out through the conical portion, which may prevent the coaxial cable from being accidentally extended beyond the distal end of the catheter.

In some cases, the conical portion may define the distal opening of the catheter, with the distal opening diameter being the second, smaller diameter. Thus, when the electrosurgical device is in the operating position, the radiating tip portion can protrude through the distal opening in the conical portion. Thus, the conical part can perform a function similar to that of the plug described above. The conical part can be used as an alternative to the plug at the distal end of the catheter, for example, to simplify the design of the instrument. In some cases, the plug may be integrated with the conical part, for example, the plug may be installed in the distal opening of the conical part.

In some embodiments, the inner conductor of the proximal coaxial transmission line may be formed from an inner core made from a first conductive material and an outer conductive sheath made from a second conductive material having a higher conductivity than the first conductive material. The first conductive material may have a higher rigidity than the second conductive material. This may increase the longitudinal rigidity of the radiating tip portion, which may facilitate the transfer of force along the radiant tip portion, for example, to pierce tissue. For example, the inner core may be made of stainless steel and the outer conductive coating may be made of silver.

According to a second aspect of the present invention, there is provided a nozzle for controlling movement of an electrosurgical device along a catheter lumen, the nozzle comprising: a first section having a connector for connecting the distal end of the nozzle to an instrument port of a surgical viewing device; a second section connected to the first section and movable along the length of the first section, wherein the second section has a holder for holding the proximal end of the catheter, while the relative movement between the second section and the first section is intended to regulate the length of the catheter that protrudes from the distal end of the nozzle ; and a third section connected to the second section and configured to move along the length of the second section, wherein the third section has a coaxial connector configured to receive the proximal end of the coaxial cable that passes in the lumen of the catheter, while the relative movement between the third section and the second section designed to control the relative position of the coaxial cable in the catheter.

The nozzle according to the second aspect of the present invention can be used with the electrosurgical instrument according to the first aspect of the present invention to control the position of the electrosurgical device in the catheter. In an independent aspect of the present invention, an electrosurgical apparatus may be provided, comprising an electrosurgical instrument according to the first aspect and a handpiece according to the second aspect, which is configured to control the position of the electrosurgical device in the catheter.

Advantageously, the nozzle according to the second aspect of the present invention allows the length of the catheter to be adjusted independently of the position of the electrosurgical device in the catheter. Thus, the length of the catheter can be adjusted so that it is placed in the instrument channel of the surgical viewing device.

In use, the proximal end of the catheter of the electrosurgical instrument may be held in the holder of the second section. Thus, the position of the catheter can be fixed with respect to the second section. The second section may include a locking mechanism for fixing the position of the second section relative to the first section. The locking mechanism may, for example, include a latch, clip, or some other suitable mechanism for holding the proximal end of the catheter and securing it in place.

The proximal end of the coaxial cable may be connected to the coaxial connector in the third section. Thus, the position of the coaxial cable (and hence the electrosurgical device) can be fixed with respect to the third section. For example, the coaxial cable may include a connector at its proximal end that is configured to mate with the coaxial connector in the third section. Alternatively, the coaxial cable may be connected directly to the coaxial connector in the third section, for example by soldered and/or welded electrical connections. The coaxial connector of the third section can be attached to the main part of the third section, for example, with screws or with glue. The coaxial connector may be connected to the electrosurgical generator, for example via an interface cable, to receive electromagnetic energy from the generator and transmit it to the coaxial cable.

The first section facilitates attachment of the nozzle relative to the inlet port of the instrumental channel of the surgical viewing device. The connector on the first section may be configured to mate with a corresponding connector on the surgical viewing device. For example, the connector may be a Luer connector, which may provide a seal between the nozzle and the instrument channel. The connector may include a mechanism for attaching the nozzle to the surgical device, for example, by means of a clip or threaded connection.

In use, the second section is movable relative to the first section to adjust the length of the catheter protruding from the nozzle. 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, by moving the second section relative to the first section, the length of the catheter in the instrument channel can be adjusted. Thus, the length of the catheter can be adjusted so that it fits into the instrumental channel.

After adjusting the length of the catheter, the third section is movable relative to the second section to move the electrosurgical device along the lumen of the catheter. Since the position of the catheter may be fixed relative to the second section and the position of the electrosurgical device may be fixed relative to the third section, movement of the third section relative to the second section may move the electrosurgical device along the lumen of the catheter. Thus, the regulation of the position of the electrosurgical device in the lumen can be carried out by moving the third section relative to the second section.

As mentioned above, the second section may include a locking mechanism for fixing the position of the second section relative to the first section. Thus, after adjusting the length of the catheter to the desired length, the length of the catheter can be fixed by using a locking mechanism to lock the position of the second section relative to the first section. The locking mechanism may be any suitable mechanism for releasing the position of the second section relative to the first section. For example, the locking mechanism may include a screw to secure the second section to the first section, or a clip to clamp the second section to the first section.

The second section may include a stopper that is movable along the length of the second section, and wherein the stopper is configured to restrict movement of the third section relative to the second section. The position of the limiter can thus be adjusted to set the desired range of movement of the third section relative to the second section. This may limit the amount by which the radiating tip portion can be extended beyond the distal end of the catheter. This can prevent accidental extrusion of the radiating tip part too far, which may cause damage to healthy tissue. The stop may, for example, have a stop surface that is configured to abut against the third section when the third section is moved distally to prevent further movement of the third section in the distal direction. The limiter may be a slider located on the surface of the second section. The stop may include a locking mechanism (eg, screw or clip) to lock it in position along the length of the second section.

In some embodiments, the second section may comprise a first set of indicators configured to indicate the maximum range of movement of the electrosurgical device along the lumen based on the position of the stop relative to the first set of indicators. Thus, the desired range of movement of the electrosurgical device along the lumen can be set by moving the limiter to the corresponding pointer on the second section. This may make it easier to set the desired range of motion, since otherwise it may be difficult for the user to determine the exact position of the radiating tip portion. For example, the pointers may indicate the length of the radiating tip portion that protrudes from the catheter when the third section abuts against the stopper.

In some embodiments, the first section may include a second set of indicators for indicating the length of the catheter in the instrumental channel based on the position of the second section relative to the second set of indicators. Thus, the user can adjust the length of the catheter by moving the second section to the appropriate pointer on the first section. This may make it easier to adjust the length of the catheter to the desired length, since it may otherwise be difficult to determine the length of the catheter when it is in the instrument channel.

In some embodiments, the first section and the second section may be arranged telescopically, with the second section being slidable along the length of the first section. For example, the first and second sections may have tubular concentric body parts, one of which is slidably inserted into the other. In some cases, the second section and the third section may be arranged telescopically, with the third section being slidable along the length of the second section. For example, the first and second sections may have tubular concentric body parts, one of which is slidably inserted into the other. The telescoping configuration can provide a compact nozzle design.

The electrosurgical instrument and handpiece described above may form part of a complete electrosurgical system. For example, the electrosurgical system may include an electrosurgical generator configured to deliver microwave energy and/or radio frequency energy; a surgical viewing device having a flexible insertion shaft for insertion into a patient's body, the flexible insertion shaft having an instrumental channel extending along its length; an electrosurgical instrument according to the first aspect of the present invention, wherein the electrosurgical instrument is sized to fit within an instrument channel; and a handpiece according to the second aspect of the present invention, wherein the proximal end of the catheter of the electrosurgical instrument is held in the 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 for receiving microwave energy and/or radio frequency energy.

The term "surgical viewing device" may be used herein to refer to any surgical device equipped with an insertion tube, which is a rigid or flexible (eg, steerable) conduit that is inserted into a patient's body during an invasive procedure. The insertion tube may comprise an instrument channel and an optical channel (for example, for transmitting light for illumination and/or capturing images of the area being treated at the distal end of the insertion tube. The instrument channel may have a diameter suitable for receiving invasive surgical instruments. Instrument channel diameter may be 5 mm or less In embodiments of the present invention, the surgical viewing device may be an ultrasonic endoscope.

In this document, the term "internal" means located closer in the radial direction to the center (eg, axis) of the tool channel and/or coaxial cable. The term "outer" means located further in the radial direction from the center (eg, axis) of the tool channel and/or coaxial cable.

In this document, the term "conductive" is used to mean electrical conductivity, unless otherwise specified in the context.

As used herein, the terms "proximal" and "distal" refer to the ends of an elongated probe. In use, the proximal end is positioned closer to the RF and/or microwave energy delivery generator, while the distal end is positioned further away from the generator.

In the present description, the term "microwave" can be used in a broad sense to indicate the frequency range from 400 MHz to 100 GHz, but preferably the range from 1 GHz to 60 GHz. Preferred fixed frequencies for microwave EM 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 preferable.

The device can deliver power at more than one of these microwave frequencies.

The term "radio frequency" or "RF" may be used to indicate a frequency in the range of 300 kHz to 400 MHz.

BRIEF DESCRIPTION OF GRAPHICS

Embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which:

in fig. 1 is a schematic representation of an electrosurgical system which is an embodiment of the present invention;

in fig. 2a and 2b are schematic sectional views of an electrosurgical instrument which is an embodiment of the present invention, wherein FIG. 2a, the electrosurgical device of the instrument is in the retracted position, and in FIG. 2b the electrosurgical device of the instrument is in working position;

in fig. 3a is a perspective view of the electrosurgical instrument of FIG. 2a and 2b;

in fig. 3b is a perspective view of the electrosurgical instrument of FIG. 2a and 2b with the instrument catheter omitted to show the internal construction of the instrument;

in fig. 4 is a perspective view of the electrosurgical instrument of FIG. 2A and 2b;

in fig. 5 and 6 are schematic side views of an electrosurgical device that is part of an electrosurgical instrument according to an embodiment of the present invention;

in fig. 7 is a schematic sectional view of a distal needle tip of an electrosurgical instrument which is an embodiment of the present invention;

in fig. 8 is a schematic view of a distal needle tip of an electrosurgical instrument which is an embodiment of the present invention;

in fig. 9a and 9b are schematic sectional views showing the deformation of respective examples of an electrosurgical instrument when it is inserted through an instrument channel that is curved backwards;

in fig. 10 is a schematic sectional view of a nozzle which is an embodiment of the present invention;

in fig. 11 and 12 are perspective views of the nozzle shown in FIG. 10, and in FIG. 11 parts of the nozzle components have been omitted to show the internal construction of the nozzle;

in fig. 13a and 13b are plan views of the nozzle shown in FIG. 10, with the distal needle in the retracted and extended (working) positions, respectively;

in fig. 14a is a sectional view of a catheter that is part of an electrosurgical instrument that is an embodiment of the present invention; and

in fig. 14b is a sectional view of a catheter that is part of an electrosurgical instrument that is another embodiment of the present invention.

DETAILED DESCRIPTION; ADDITIONAL OPTIONS AND PREFERRED OPTIONS

In FIG. 1 is a schematic representation of an electrosurgical ablation device 100 capable of delivering microwave energy and/or radio frequency energy to the distal end of an invasive electrosurgical instrument. System 100 includes a generator 102 for controlled delivery of microwave energy and radio frequency energy. A suitable generator for this purpose is described in WO 2012/076844, which is incorporated herein by reference. The generator may be configured to monitor the reflected signals received back from the tool to determine an appropriate power level for delivery. For example, the generator may be configured to calculate the impedance received at the distal end of the instrument to determine the optimal delivery power level.

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 via a fluid flow line to a fluid delivery device such as a syringe, for example, if fluid is to be transferred to the distal end of an electrosurgical instrument. .

The nozzle 106 houses an instrument control mechanism that is used to control the longitudinal movement (back and forth) of the electrosurgical instrument. Nozzle 106 may also contain control mechanisms (eg triggers) to actuate one or more control wires or pushers, as needed. An example of a nozzle is described in more detail below with reference to FIG. 10-12. The function of the tip is to feed the input from the generator 102 and any other inputs into an integral flexible instrument cable that exits the distal end of the tip 106 and is sized to fit through the instrument channel of the surgical viewing device.

The nozzle 106 is connected to the input port 128 of the surgical viewing device 114. The surgical viewing device 114 includes a main body 116 having several input ports and an output port from which the shaft 120 of the instrument extends. The barrel 120 of the tool includes an outer shell that surrounds a plurality of gaps. Through a plurality of gaps, various parts are brought from the main body 116 to the distal end of the barrel 120 of the tool. One of the many gaps is an instrumental channel through which the instrumental cable passes. Other lumens may include a channel for transmitting optical radiation, for example, to provide illumination at the distal end or to collect images from the distal end, and a channel for ultrasonic signals for transmitting an ultrasonic signal. The main body 116 may include an eyepiece 122 or other imaging device that provides a view of the distal end.

The viewing ultrasonic device typically contains an ultrasonic transducer at the distal tip of the instrument shaft, outside the outlet of the channel for ultrasonic signals. Signals from the ultrasonic transducer may be transmitted via a suitable cable 126 back down the tool shaft to a processor 124 which may generate images in known manner. The instrument channel may be shaped in the instrument shaft to guide the instrument emerging from the instrument channel through the field of view of the ultrasound system to provide information about the location of the instrument in the target area.

An integral flexible instrument cable emerges from the distal end of the handpiece 106 and is received in an instrument channel in the instrument shaft 120 of the surgical viewing device 114. The integral flexible instrument cable has a distal end assembly 118 (not illustrated to scale in FIG. 1) shaped to allow it to pass through the instrument channel of the surgical viewing device 114 and protrude outward (eg, inside the patient) at the distal end of the instrument shaft 120.

The design of the distal end assembly 118 described below can be specifically designed for use with an EUS endoscopic ultrasound device where the maximum outer diameter of the distal end assembly 118 is equal to or less than 1.2 mm, such as less than 1 .0 mm, and the length of the electrosurgical instrument can be equal to or greater than 1.2 m.

It may be necessary to control the position of at least the distal end of the tool barrel 120. The main body 116 may include a control actuator that is mechanically connected to the distal end of the tool barrel 120 by one or more control wires (not illustrated) that extend through the tool barrel 120 . The control wires can run inside the channel of the instrument or inside their own dedicated channels. The operating mechanism may be a lever or rotary knob, or any other known device for manipulating a catheter. Manipulation of the instrument shaft 120 may be performed using software, such as using a virtual 3D map assembled from computed tomography (CT) images.

An electrosurgical instrument 200 according to an embodiment of the present invention is illustrated in FIG. 2a, 2b, 3a, 3b, and 4. The electrosurgical instrument 200 includes an integral instrument cable containing an electrosurgical device 202 located 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 can be moved. 202 is movable along the catheter between a retracted position as shown in FIG. 2a and the operating position as shown in FIG. 2b. In FIG. 2a and 2b are schematic side sectional views of an electrosurgical instrument 200; in fig. 3a is a perspective view of instrument 200 showing catheter 204 transparent for illustrative purposes to show electrosurgical device 202 within catheter 204; and in fig. 3b is a perspective view of instrument 200 with catheter 204 omitted for illustrative purposes. In FIG. 4 is a perspective view of an electrosurgical instrument with the electrosurgical device 202 in an operating position.

The electrosurgical device 202 is shown in more detail in FIG. 5 and 6. The electrosurgical device 202 includes a flexible coaxial cable 206 and a radiating tip portion 208 that is attached at the distal end of the coaxial cable 206. The coaxial cable 206 may be a conventional 50 ohm flexible coaxial cable suitable for transmitting microwave and RF energy. A coaxial cable contains a center conductor and an outer conductor, which are separated by a dielectric material. Coaxial cable 206 may be connected at its proximal end to a generator, such as generator 102, to receive microwave and/or radio frequency energy.

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 coupled 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 to target biological tissues. In the example shown, the distal needle tip 212 is configured as a half-wave transformer for delivering microwave energy to target biological tissues to ablate the target tissues.

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 attached to the coaxial cable 206 by a sleeve 216 installed over the junction between the coaxial cable 206 and the radiating tip portion 208. The sleeve 216 is made of a conductive material ( for example, brass) and electrically connects the outer conductor of the coaxial cable 206 with the outer conductor 218 of the proximal coaxial line 210 transmission. The outer conductor 218 is made of a nitinol tube.

Sleeve 216 includes a substantially cylindrical body 219 that is mounted on the distal end of coaxial cable 206 and which is electrically connected to the outer conductor of the coaxial cable 206. Sleeve 216 further includes a distal portion 220 that extends from the body 219 of sleeve 216 to the proximal end of the outer conductor 218 of the proximal coaxial transmission line 210. The distal portion 220 of the sleeve 216 includes a distal surface that is rounded. This can reduce friction between the electrosurgical device 202 and the catheter 204 as the electrosurgical device 202 is moved along the catheter 204 by avoiding sharp edges on the contact surface between the coaxial cable 206 and the radiating tip portion 208. It can also make it easier to move the electrosurgical device 202 along the catheter 204 when catheter 204 is bent backwards.

The radiant tip portion 208 has a smaller outer diameter than the coaxial cable 206. As a result, the radiant tip portion 208 can be more flexible than the coaxial cable 206, which can make it easier to bend the radiant tip portion 208 and/or guide the radiant tip portion to a hard-to-reach area to be treated. By making the outer diameter of the radiant tip portion 208 smaller, it is also possible to reduce the size of the insertion hole made when the radiant tip portion 208 is inserted into tissues, which can minimize bleeding and facilitate healing. Preferably, the radiating tip portion may have an outer diameter that is 1.2 mm or less, such as 1.0 mm or 0.9 mm. The coaxial cable 206 may have an outer diameter that is approximately 2.0 mm.

The catheter 204 is a flexible tube made of an insulating material (eg, PEEK or PTFE). The catheter 204 is sized to fit into the working channel of a surgical viewing instrument. The catheter 204 defines a lumen in which the electrosurgical device 202 is received and along which the electrosurgical device 202 can be moved.

The plug 222 is mounted on the distal end of the catheter 204. The plug 222 has a body 224 that is located within the distal end of the catheter 204. The body 224 includes a spike (or bulge) 226 located on the outer surface of the body 224 that forms an interference fit with the catheter 204 to secure plug 222 to the distal end of catheter 204. Thus, plug 222 can be attached to the distal end of catheter 204 without the need for adhesive (although glue can be used to further attach plug 222 to 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 presence of the rounded distal surface 228 of the plug 222 helps to avoid sharp edges around the distal end of the catheter 204. This can facilitate insertion of the electrosurgical device 200 along the instrument channel of the surgical viewing device by reducing friction between the catheter 204 and the instrument channel at the distal end of the catheter 204. The plug can be manufactured PEEK or some other insulating material.

The plug 222 has a longitudinal passage 230 passing through it. The passage 230 is sized so that the radiating tip portion 208 can pass through it, but to prevent the coaxial cable 206 from passing through it. Thus, the electrosurgical device 202 may be advanced along the catheter 204 to allow the radiant tip portion 208 to pass through the passage, whereby the length of the radiant tip portion 208 protrudes beyond the distal end of the catheter 204 (eg, as shown in FIG. 2b).

The passage 230 includes a proximal opening 232 located at the proximal end of the body 224 within the catheter 204. The distal opening 234 of the passage 230 is located in the distal surface 228 of the plug 222. portion 208 protrudes through distal opening 234 of port 230. Port 230 is longer than distal needle tip 212, i. the distance between the proximal opening 232 and the distal opening 234 of passage 230 is greater than the length of the distal needle tip 212. Thus, as shown in FIG. 2a, when the electrosurgical device 202 is in the retracted position, the distal needle tip 212 may be located entirely in the passage 230 in the plug 222. in a retracted position. This can prevent the edge 236 from engaging with the proximal opening 232 of the passageway 230 when the electrosurgical device 202 is moved from the retracted position to the operating position.

Edge 236 of outer conductor 218 is chamfered, such as beveled, to further prevent edge 236 from snagging on proximal opening 232 of passage 230. Proximal opening 232 of passage flares outward, i. the diameter of the opening 232 increases in the proximal direction. Thus, the flared proximal opening 232 facilitates the insertion of the radiating tip portion 208 into the passage to prevent the radiating tip portion 208 from snagging on the proximal opening 232 and to facilitate the movement of the radiating tip portion 208 through the passage 230.

The passageway 230 assists in guiding the radiating tip portion 208 as the electrosurgical device 202 is moved between the retracted and operating positions. Port 230 is centered relative to the longitudinal axis of catheter 204, whereby passage 230 assists in centering radiant tip 208 as radiant tip 208 moves through passage 230.

In FIG. 2a, the electrosurgical device 202 is in a retracted position with the distal needle tip 212 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 plug 222. The electrosurgical instrument 200 can be inserted into the instrument channel of the surgical viewing device and guided to a desired position when the electrosurgical device 202 is in a retracted position. This may make it easier to insert the electrosurgical instrument 200 into the instrument channel because it prevents the radiating tip portion 208 from getting caught in the instrument channel.

After directing the electrosurgical instrument 200 to the desired position, the electrosurgical device 202 can be moved to the operating position. From the retracted position shown in FIG. 2a, this can 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 can be moved to reach the operating position shown in FIG. 2b. Since the electrosurgical device 202 protrudes from the distal opening 234 of the passage 230, the radiating tip portion 208 can be inserted into biological tissues. Once the distal needle tip 212 has reached the target area to be treated (eg, tumors), microwave energy can be delivered to the distal needle tip to ablate the target tissues.

After treating the target tissues, the electrosurgical device 202 can be moved back to a retracted position so that the radiating tip portion 208 is no longer extended. This is achieved by moving the electrosurgical device 202 along the catheter 204 in the proximal direction.

A sharp edge 238 is provided around the distal opening 234 of the passageway 230. The sharp edge 238 assists in scraping away tissue or blood adhering to the radiating tip portion 208 as the electrosurgical device 202 is moved from the operating position to the retracted position. This may prevent tissue and/or blood from entering the catheter when the radiating tip portion 208 is drawn back into the catheter 204, which may contaminate the catheter 204 or interfere with the movement of the electrosurgical device 202 in the catheter.

Next, the structure of the radiating tip portion 208 of the electrosurgical device 202 will be described in more detail with reference to FIG. 5 and 6. For illustrative purposes, outer conductor 218 is omitted from FIG. 6 to show the internal construction of the radiating tip portion 208. Also for illustrative purposes, the section of the proximal coaxial transmission line 210 has been omitted from FIG. 5 and 6 as indicated by broken lines 502.

The proximal coaxial transmission line 210 includes a proximal dielectric sleeve 504 that is located 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 located around the distal portion of the inner conductor 214 to form the distal needle tip 212. The distal dielectric the sleeve 506 is made of a different dielectric material than the dielectric material of the proximal dielectric sleeve 504. In one example, the proximal dielectric sleeve 504 may be made of PTFE (for example, it may be a PTFE tube) and the distal dielectric sleeve may be made of PEEK. The distal portion of the outer conductor 218 overlaps the proximal portion of the distal dielectric sleeve 506. Thus, the distal portion of the proximal coaxial transmission line 210 comprises the proximal portion of the distal dielectric sleeve 506. The materials of the proximal and distal dielectric sleeves and the length of overlap between the outer conductor 518 and the distal dielectric sleeve 506 may be chosen to adjust the electrical length of the radiating tip portion 208 to match the impedance to the target tissues.

Outer conductor 218 may be made of nitinol, which is flexible and provides sufficient longitudinal rigidity to puncture tissue (eg, duodenal wall). The inner conductor is made of a silver-plated stainless steel core. The stainless steel core provides additional rigidity to the radiant tip 208, while the silver plating can increase the conductivity of the inner conductor 214 to reduce losses in the radiant tip 208.

A dielectric spacer 508 is installed at the interface between the radiating tip portion 208 and the coaxial cable 206. The dielectric spacer 508 is located inside the sleeve 216 and is installed around the inner conductor 214. Thus, the dielectric separator 508 is located between the inner conductor 214 and the sleeve 216. This can increase the penetration distance between the inner conductor 214 and the sleeve 216 at the junction between the coaxial cable 206 and the radiating ferrule 208. This can improve the electrical safety of the device at the junction. The dielectric separator 508 may, for example, be a PTFE washer or a washer made from other suitable insulating material.

As mentioned above, the distal needle tip 212 is configured as a half-wave transformer for delivering microwave energy to tissue. Thus, when delivering microwave energy to the distal needle tip 212, the distal needle tip 212 can radiate microwave energy to surrounding tissue. The distal needle tip 212 includes a pointed tip 510 at its distal end to facilitate insertion of the emitting tip portion 208 into target tissues. The pointed tip 510 is made of a dielectric material having a higher rigidity than the distal dielectric sleeve 506. This may make the pointed tip 510 sharper and may make it easier to sharpen the pointed tip 510. For example, the pointed tip 510 may be made of zirconia.

In FIG. 7 is a more detailed view of the pointed tip 510 mounted on the distal end of the distal dielectric sleeve 506. The pointed tip 510 includes a tapered portion 702 that tapers to a sharp end and assists in puncturing tissue. The tapered tip also includes a main portion 704 which extends from the proximal end of the conical portion 702 and which is received in an opening at the distal end of the distal dielectric sleeve. The main body 704 of the pointed tip 510 includes a protrusion (or bulge) 706 that forms an interference fit with the wall of the opening to hold the main body 704 in the opening. Thus, when the body 704 is inserted into the opening, a "tight fit" connection can be formed. This may allow the pointed tip 510 to be installed in the distal dielectric sleeve 506 without adhesive. This may also make it easier to replace the pointed tip 510, for example, if the pointed tip 510 is damaged.

In FIG. 8 shows an example of another pointed tip 802 mounted on the distal end of the distal dielectric sleeve 506. The pointed tip 802 includes a main body 804 that is located in an opening at the distal end of the distal dielectric sleeve 506. The main body 804 includes a protrusion 806 for securing the main body 804 in the opening. . The pointed tip 802 further includes a tapered portion 808 that protrudes from an opening in the distal dielectric sleeve 506 and tapers to a tissue piercing point. The conical 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, higher angle relative to the longitudinal direction. Thus, the pointed tip 802 can be said to be "biangular". The sharp end of the pointed tip 802 is defined 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 conical portion 808 can be reduced. This can reduce the brittleness of the pointed tip 802 and reduce the likelihood of the sharp end of the pointed tip 802 breaking off.

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

In FIG. 9a is a sectional view of an electrosurgical instrument 900 according to an embodiment of the present invention, in which the distal portion of the instrument 900 is curved backwards. In FIG. 9b is a sectional view of an electrosurgical instrument 902 according to another embodiment of the present invention, in which the distal portion of the instrument 902 is curved backwards.

The electrosurgical instruments 900 and 902 have a similar configuration to the electrosurgical instrument 200 described above. The electrosurgical instrument 900 includes a catheter 904 in which an electrosurgical device 906 is located. The electrosurgical device 906 includes a coaxial cable 908 having a radiating tip portion 910 located at the distal end of the coaxial cable 908. The electrosurgical device 906 is movable along the catheter 904 between a retracted position, in which the radiating tip portion 910 is located in the catheter 904, and the operating position in which the radiating tip portion 910 protrudes from the distal end of the catheter 904. In the configuration shown in FIG. 9a, the electrosurgical device 906 is in an operating position.

Similarly, the electrosurgical instrument 902 includes an electrosurgical device 912 located in the catheter 914. The electrosurgical device 912 includes a coaxial cable 916 and a radiating tip portion 918 at the distal end of the coaxial cable 916. The electrosurgical device 912 is movable along the catheter 914 between a retracted position in which the radiating tip portion 918 is located in the catheter 914, and the operating position in which the radiating tip portion 918 protrudes from the distal end of the catheter 914. In the configuration shown in FIG. 9b, the electrosurgical device 912 is in an operating position.

In FIG. 9a, the distal portion 920 of the catheter 904 is curved backwards, i. the distal portion 920 of the catheter 904 is bent. As can be seen in FIG. 9a, the distal portion of the coaxial cable 908 is located in the distal portion 920 of the catheter 904 and is also bent. Thus, in order to move the electrosurgical device 906 between the retracted position and the operating position (shown in Fig. 9a), the distal portion of the coaxial cable 908 must be bent. through the flexed distal portion 920 of the catheter 904. When the electrosurgical device 906 is moved from the operating position to the retracted position, the distal portion of the coaxial cable 908 must be unfolded as it is pulled out of the folded distal portion 920 of the catheter 904.

Bending and unbending coaxial cable 908 may require significant force due to the rigidity of coaxial cable 908. Coaxial cables commonly used in electrosurgical devices, such as Sucoform 86 coaxial cable, have a relatively rigid (eg, heavily tinned) outer sheath. While the presence of such an outer sheath may make it easier to drive the device in a straight path, it may require significant force to bend the cable. As a result, when the distal portion of the catheter 904 is curved backward, significant force may be required on the electrosurgical device 906 to move it between the retracted and operating positions. This can result in a significant amount of friction between the coaxial cable 908 and the catheter 904 in the bent portion 920, which can reduce the accuracy of the position control of the radiating tip portion 910.

The emitting tip portion 918 of the electrosurgical device 912 (FIG. 9b) is longer than the emitting tip portion 910 of the electrosurgical device 906 (FIG. 9a). As a result, when the distal portion 922 of the catheter 914 is bent (eg, bent backwards, as shown in FIG. 9b), it may not be necessary to move the coaxial cable 916 through the bent portion 922 of the catheter 914 when moving the electrosurgical device 906 into operating position. The radiant tip 918 can be more flexible than the coaxial cable 916 because the radiant tip 918 has a smaller diameter than the coaxial cable and does not have a rigid outer jacket. Thus, only a relatively small force may be required to bend the radiating tip portion 918 as it moves through the folded distal portion 922 of the catheter 914.

As shown in FIG. 9b, by making the radiating tip portion 918 long enough, the distal end of the coaxial cable 916 does not enter the bent distal portion 922 of the catheter 914 when the electrosurgical device 912 is in the operating position, so that the distal end of the coaxial cable 916 does not need to be bent when the electrosurgical device is moved. 912 between retracted and working positions. Preferably, the radiating tip portion may be 140 mm or more in length. This may ensure that the coaxial cable 916 does not enter the backward curved portion of the catheter 914 when the electrosurgical device 912 is in the operating position.

The configuration shown in Fig. 9b can thus reduce friction between the electrosurgical device 912 and the catheter 914 as the electrosurgical device 912 is moved along the catheter 914. This can improve the position control of the radiating tip portion 918.

The electrosurgical device 912 further includes an outer sheath 924 located around the proximal portion of the radiating tip portion 918. The outer sheath 924 is made of or coated with a non-stick material, for example, the outer sheath 924 may be a PTFE tube. The outer sheath 924 may help reduce friction between the radiating tip portion 918 and the bent distal portion 922 of the catheter 914. This may facilitate movement of the electrosurgical device 912 between the retracted and operating positions. The outer sheath 924 may also help reduce lateral movement of the radiant tip portion 918 in the catheter by acting as a spacer between the radiant tip portion 918 and the catheter 914. This may facilitate movement of the radiant tip portion along the folded distal portion 922 of the catheter 914.

In FIG. 10 is a schematic sectional view of a nozzle 1000 according to an embodiment of the present invention. A perspective view of the nozzle 1000 is shown in FIG. 11, where portions of the components of nozzle 1000 have been removed to show the internal construction of nozzle 1000. An additional perspective view of nozzle 1000 is shown in FIG. 12. The handpiece 1000 may be used with an electrosurgical instrument of the present invention, such as electrosurgical instrument 200, 900, 902, to move the instrument's electrosurgical device along the instrument's catheter between a retracted position and an operating position.

The nozzle 1000 includes a first section 1002 that has a generally cylindrical hollow body 1004. A connector 1006 is provided at the distal end of the hollow body 1004, the connector 1006 being configured to mount the nozzle to the inlet port of the instrument channel of the surgical viewing device. Connector 1006 may be configured to pair with a corresponding connector at the input port. The connector 1006 may include a Luer fitting (or some other suitable fitting) to provide a leak-tight connection between the nozzle 1000 and the instrument channel of the surgical viewing device.

The nozzle 1000 further comprises a second section 1008. The second section 1008 is formed from a generally cylindrical hollow body 1010 that is telescopically mounted on the first section 1002, whereby the second section 1008 is slidable longitudinally along the length of the first section 1002. The second section 1008 includes a locking screw 1012 for fixing the position of the second section 1010 relative to the first section 1002. The locking screw 1012 engages in a threaded hole in the side wall of the hollow body 1010. By tightening the locking screw 1012 in the threaded hole, the locking screw 1012 engages with the base part 1004 of the first section 1002 to fix the position of the second section 1010 relative to the first section 1002. By loosening the locking screw 1012 in the threaded hole, the locking screw disengages from the first section 1002, whereby the second section 1008 can slide relative to regarding the first section 1002.

The second section 1008 includes a holder 1014 located on the inside of the main body 1010 of the second section 1008. The holder 1014 is configured to hold the proximal end of the catheter of the electrosurgical instrument. Holder 1014 may, for example, be a latch or clip configured to hold the proximal end of the catheter. In another example, the holder 1014 may be a surface to which the proximal end of the catheter may be attached (eg, with adhesive). Thus, when the proximal end of the catheter is held in the holder 1014, the position of the catheter is fixed relative to the second section 1008. Thus, sliding movement of the second section 1008 relative to the first section 1002 results in movement of the catheter relative to the first section 1002.

The nozzle 1000 further comprises a third section 1016. The third section 1016 is formed from a generally cylindrical hollow body 1018, which is telescopically mounted on the second section 1008, whereby the third section 1016 is slidable longitudinally along the length of the second section 1008. Coaxial connector 1020 is mounted on the proximal end 1019 of the main body 1018. The proximal end 1022 of the coaxial connector 1020 is open on the outside of the body 1018 of the third section 1016. The proximal end 1022 of the coaxial connector 1020 may be connected to an electrosurgical generator, for example, via a connecting cable (not shown).

The distal end 1024 of the coaxial connector 1020 is located within the hollow body 1018 of the third section 1016. The distal end 1024 of the coaxial connector 1020 is configured 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 that may be electrically connected to the center conductor and outer conductor of the coaxial cable, respectively (eg, via soldered or welded joints). Alternatively, the distal end 1024 of the coaxial connector 1020 may be adapted to mate with a corresponding connector at the proximal end of the coaxial cable. The coaxial connector 1020 is configured to transmit electromagnetic energy from a cable connected to its proximal end 1022 to a coaxial cable connected to its distal end 1024.

The sliding stop 1026 is mounted on the outer surface of the main body 1010 of the second section 1008. The sliding stop 1026 is slidable along the outer surface of the main part 1010 of the second section 1008. engaged in the threaded hole in the sliding stop. The sliding stop 1026 includes a stop surface 1030 that is configured to abut against the distal surface 1029 of the main body 1018 of the third section 1016 when the third section moves distally (i.e., towards the first section 1002) to prevent further movement of the third section 1016 in the distal direction. Thus, the range of motion of the third section 1016 relative to the second section 1008 can be adjusted by adjusting the position of the sliding stop 1026 on the second section 1008.

In the examples shown in FIG. 10 and 11, the proximal end of the electrosurgical instrument 1031 is mounted in the handpiece 1000. The electrosurgical instrument may be an electrosurgical instrument according to an embodiment of the present invention, for example, as described above. The proximal end of the catheter 1032 of the instrument 1031 is held in the holder 1014 in the second section 1016 of the nozzle 1000. sliding along the catheter 1032. The electrosurgical instrument 1031 passes through the hollow main portions of the first, second, and third sections of the handpiece 1000. The distal portion of the electrosurgical instrument 1031 exits the handpiece through a connector 1006 at the distal end of the first section 1002.

Reinforcing tube 1036 is provided around the outer surface of the proximal portion of coaxial cable 1034. Reinforcing tube 1036 is attached to coaxial connector 1020. Reinforcing tube 1036 is made of a rigid material such as a hard metal or plastic. The reinforcing tube 1036 helps increase the longitudinal stiffness of the proximal portion of the coaxial cable 1034 to facilitate the transfer of longitudinal force to the coaxial cable 1034 when the third section 1016 is moved relative to the second section 1008. 1036 could slide inside the catheter 1032.

In use, the distal portion of the electrosurgical instrument 1031 that exits the connector 1006 may be inserted into the instrument channel of the surgical viewing device. The connector 1006 of the nozzle 1000 can then be connected to a corresponding connector on the input port of the surgical viewing device to attach the nozzle 1000 to the surgical viewing device. The length of the catheter 1032 in the instrument channel can then 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 (via the holder 1014), moving the second section 1008 relative to the first section 1002 changes the length of the catheter 1032 , which exits the connector 1006, and hence the length of the catheter 1032 located in the instrument channel. A set of indicators 1040 is provided on the outer surface of the main body 1004 of the first section 1002. Each indicator of the set of indicators 1040 indicates the length of the catheter exiting the nozzle when the distal surface 1041 of the second section 1008 is aligned with that indicator. Thus, the second section 1008 can move along the first section 1002 to the pointer on the first section 1002 corresponding to the desired length of the catheter 1032 in the instrument channel. Once the desired length is obtained, the position of the second section 1008 can be fixed relative to the first section 1002 by tightening the locking screw 1012.

After adjusting the length of the catheter 1032, the coaxial cable 1034 can be moved along the catheter 1032, for example, to extend 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 third section 1016 relative to the second section 1008 is transferred 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, as a result of which the longitudinal movement of the third section 1016 is transmitted to the coaxial cable 1034. When moving the third section 1016 in the proximal direction relative to the second section 1008, the reinforcing tube slides into the expanded proximal portion 1038 of the catheter 1032.

Because catheter 1032 is fixed relative to second section 1008, sliding movement of third section 1016 relative to second section 1008 results in sliding movement of coaxial cable 1034 in catheter 1032. Thus, when handpiece 1000 is used with an electrosurgical instrument of the present invention (e.g., electrosurgical instrument 200), the electrosurgical device can be moved between the retracted and operating positions by moving the third section 1016 back and forth relative to the second section 1008. can be moved to a retracted position by moving the third section 1016 in a distal direction relative to the second section 1008.

The user can adjust the position of the slide stop 1026 on the second section 1008 to set the maximum anterior 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 operating position. Thus, the sliding stopper 1026 can prevent the radiating tip portion from being pushed too far beyond the distal end of the catheter 1032. A set of indicators 1042 is provided on the outer surface of the body 1010 of the second section 1008. Each indicator from the set of indicators 1042 indicates the maximum extension of the radiating tip portion beyond the distal the end of the catheter 1032 when the sliding stop 1026 is aligned with this index and the distal surface 1029 of the third section 1016 abuts against the stop surface 1030 of the sliding stop 1026. The sliding stop 1026 can thus be moved to the appropriate index of the set of indexes 1042 to set the desired maximum extension radiating tip.

In FIG. 13a and 13b depict the use of a handpiece 1000 to move the electrosurgical device of the instrument 1031 between a retracted position and an operating position. In FIG. 13a, the electrosurgical device of the instrument 1031 is in the retracted position, i. the radiating tip portion of the electrosurgical device does not protrude beyond the distal end 1044 of the catheter 1032. FIG. 13b, the electrosurgical device of the instrument 1031 is in the operating position, i. e. the radiating tip portion 1046 of the electrosurgical device extends beyond the distal end 1044 of the catheter 1032. In this configuration, electromagnetic energy can be delivered to the radiant tip portion 1046 via a coaxial connector 1020 to deliver energy to target tissues.

To change from the configuration shown in FIG. 13A to the configuration shown in FIG. 13b, the stopper 1026 may first be moved to a desired position on the body 1010 of the second section 1008. The third section 1016 may then be slid over the second section 1008 in a distal direction. The third section 1016 can be advanced until the distal surface 1029 of the third section 1016 abuts the sliding stop 1026 as shown in FIG. 13b. After target tissue treatment is completed, the radiating tip portion 1046 can be retracted into the catheter 1032 by sliding the third section 1016 proximal to the second section to return to the configuration shown in FIG. 13a. For illustrative purposes, the length of tool 1031 is not shown in FIG. 13a and 13b as indicated by dotted lines 1048.

In FIG. 14a is a sectional view of a catheter 1400 that can be used as part of an electrosurgical instrument of the present invention. The catheter 1400 defines a lumen 1402 that passes through it 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 dimensions for the first and second diameters are 2.70 mm and 2.30 mm, respectively. The stepped section 1412 connects the proximal section 1404 and the distal section 1408. The larger diameter of the proximal section 1404 is provided such that the proximal section 1404 can receive the proximal section of the coaxial cable of the electrosurgical device, which contains a reinforcing element (which increases the effective outer diameter of the proximal section of the coaxial cable).

In FIG. 14b is a sectional view of another catheter 1414 that may be used as part of an electrosurgical instrument of the present invention. The catheter 1414 defines a lumen 1416 that passes through it 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 provided such that the proximal section 1404 can receive the proximal section of the coaxial cable of the electrosurgical device, which contains a reinforcing element . The proximal section 1418 and the intermediate section 1422 are connected via a stepped section 1426.

The tapered section 1428 is located at the distal end of the catheter 1414. The tapered section 1428 assists in reducing the diameter of the catheter 1414 at the distal end of the catheter from a second diameter 1424 to a third, smaller diameter 1430. third diameter 1430. The third diameter 1432 is set to be 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. Thus, the radiating tip can protrude through the distal opening 1432 (for example, when the electrosurgical device is in the operating position), but the coaxial cable (which has a larger outer diameter than the radiating tip) can be prevented from passing through the distal opening 1432. Thus, the conical section 1428 can perform a similar function to the plug 222 at the end of the catheter 204. By providing a conical section 1428 at the distal end of the catheter 1414, a plug at the distal end of the catheter 1414 may not be needed. This can simplify the design of the electrosurgical instrument. Exemplary dimensions for the first, second, and third diameters are 2.70 mm, 2.30 mm, and 1.10 mm, respectively.

Different sections of catheters 1400 and 1414 can be made by connecting tubes of different diameters to each other. Alternatively, catheters 1400 and 1414 may be formed from a single tube that is extruded to provide multiple diameters. This can be done by extruding a tube of a first diameter and then working a portion of the tube to reshape that portion to a different (eg larger) diameter.

Claims (38)

1. An electrosurgical instrument for delivering microwave energy for ablation of target biological tissues, comprising: a flexible catheter having a lumen through it, the catheter sized to be inserted through the instrument channel of the surgical viewing device; and an electrosurgical device located in said catheter lumen, the electrosurgical device comprising: a flexible coaxial cable configured to transmit microwave energy; and a radiating tip connected to the distal end of the coaxial cable for receiving microwave energy, and the radiating tip has a smaller outer diameter than the flexible coaxial cable, while the radiating tip contains: a proximal coaxial transmission line for microwave energy; and a distal needle tip in contact with the distal end of the proximal coaxial transmission line, wherein the distal needle tip is configured to radiate microwave energy into biological tissues, wherein the electrosurgical device is made with the possibility of longitudinal movement in the specified lumen between the operating position, in which the distal needle tip protrudes beyond the distal end of the catheter, and the retracted position, in which a part of the distal needle tip is in the catheter. 2. An electrosurgical instrument according to claim. 1, characterized in that the distal needle tip is configured to operate as a half-wave transformer for delivering microwave energy from the distal needle tip to biological tissues. 3. Electrosurgical instrument according to claim. 1 or 2, characterized in that the catheter contains a limited passage at its distal end, and the limited passage is sized to allow the passage of the radiating tip part and prevent the passage of a flexible coaxial cable. 4. Electrosurgical instrument according to claim. 3, characterized in that the limited passage passes through the plug installed at the distal end of the catheter. 5. Electrosurgical instrument according to any of the preceding claims, characterized in that the distal surface of the catheter is rounded. 6. Electrosurgical instrument according to any one of paragraphs. 3-5, characterized in that the distal needle tip is held in a limited passage in a retracted position. 7. An electrosurgical instrument according to any one of the preceding claims, characterized in that the distal needle tip comprises a pointed tip at its distal end. 8. Electrosurgical instrument according to claim 7, characterized in that the pointed tip is made of a rigid insulating material. 9. Electrosurgical instrument according to claim 7 or 8, characterized in that the distal needle tip includes a distal dielectric sleeve around the central conductive element, and wherein the pointed tip is fixed in the opening at the distal end of the distal dielectric sleeve. 10. Electrosurgical instrument according to any one of paragraphs. 7-9, characterized in that the pointed tip is made of zirconium dioxide. 11. An electrosurgical instrument according to any one of the preceding claims, characterized in that the proximal coaxial transmission line comprises an inner conductor separated from the outer conductor by a dielectric sleeve, the inner conductor comprising a distal portion that protrudes beyond the distal end of the outer conductor, and wherein the distal needle is the tip has the length of the distal part of the inner conductor. 12. An electrosurgical instrument according to claim 11, characterized in that the outer conductor of the proximal coaxial transmission line is made of nitinol. 13. An electrosurgical instrument according to any one of the preceding claims, characterized in that the radiating tip portion is attached to the coaxial cable by means of a sleeve mounted over the junction therebetween, the sleeve having a distal surface that is rounded. 14. An electrosurgical instrument according to any one of the preceding claims, characterized in that the length of the radiating tip portion is equal to or greater than 140 mm. 15. An electrosurgical instrument according to any one of the preceding claims, characterized in that the radiating tip portion has a non-stick material on its outer surface. 16. Electrosurgical instrument according to any of the preceding claims, characterized in that the proximal part of the coaxial cable is attached to a rigid reinforcing element. 17. An electrosurgical instrument according to claim 16, characterized in that the proximal part of the lumen has a larger diameter than the distal part of the lumen to receive the proximal part of the coaxial cable. 18. An electrosurgical instrument according to any of the preceding claims, characterized in that the inner conductor of the proximal coaxial transmission line is formed from 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. 19. A nozzle for controlling the movement of an electrosurgical device along the lumen of the catheter, containing: a first section having a connector for connecting the distal end of the handpiece to an instrument port of the surgical viewing device; a second section connected to the first section and configured to move along the length of the first section, and the second section has a holder for holding the proximal end of the catheter, while the relative movement of the second section and the first section is designed to control the length of the catheter that protrudes from the distal end of the nozzle; and a third section connected to the second section and configured to move along the length of the second section, wherein the third section has a coaxial connector configured to receive the proximal end of the coaxial cable, which is passed in the lumen of the catheter, while the relative movement of the third section and the second section is intended to control of the relative position of the coaxial cable in the catheter. 20. The nozzle according to claim 19, characterized in that the second section has a locking mechanism for fixing the position of the second section relative to the first section. 21. The nozzle according to claim. 19 or 20, characterized in that the second section contains a limiter, which is configured to move along the length of the second section, and moreover, the limiter is configured to limit the movement of the third section relative to the second section. 22. Nozzle according to any one of paragraphs. 19-21, characterized in that the first section and the second section are arranged telescopically, and the second section is slidable along the length of the first section. 23. The nozzle according to any one of paragraphs. 19-22, characterized in that the second section and the third section are arranged telescopically, and the third section is slidable along the length of the second section. 24. An electrosurgical system for delivering microwave energy for ablation of target biological tissues, comprising: an electrosurgical generator configured to supply microwave energy; a surgical viewing device having a flexible insertion cord for insertion into a patient's body, the flexible insertion cord having an instrumental channel extending along its length; electrosurgical instrument according to any one of paragraphs. 1-18, wherein the electrosurgical instrument is sized to fit within the instrument channel; and nozzle according to any one of paragraphs. 19-23, wherein the proximal end of the catheter of the electrosurgical instrument is held in the 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 microwave energy.

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