Electrosurgical Equipment

Abstract

To prevent a radiating tip portion from catching on an instrument channel when a device is inserted into the instrument channel, which may cause damage to the instrument channel and / or radiating tip portion.SOLUTION: An electrosurgical device has a radiating tip portion for delivering electromagnetic energy to biological tissue, where the electrosurgical device is disposed in a catheter. The electrosurgical device is movable relative to the catheter between a deployed position, where the radiating tip portion is exposed, and a retracted position, where the radiating tip portion is contained in the catheter. In this manner, the radiating tip portion may be retracted until the moment it is used. This may facilitate insertion of the device through an instrument channel of a surgical scoping device.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electrosurgical instrument for delivering electromagnetic energy to living tissue to ablate targeted tissue. In particular, the probe is configured to be insertable through a channel of a surgical scope device or catheter that can be introduced to a treatment site in a non-invasive manner. The probe can be positioned to ablate tissue such as tumors, cysts, or other lesions. The probe may be particularly suited for treatment in the pancreas. [Background technology]

[0002] Electromagnetic (EM) energy, and particularly microwave and radio frequency (RF) energy, has been found to be useful in electrosurgery due to its ability to cut, coagulate, and ablate body tissue. Typically, a device for delivering EM energy to living tissue includes a generator containing an EM energy source and an electrosurgical instrument connected to the generator to deliver energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into a patient's body. However, percutaneous placement of the instrument within the body can be difficult, for example, when the target site is in a moving lung or a thin-walled section of the gastrointestinal (GI) tract. Other electrosurgical instruments can be delivered to the target site through a surgical scope device (e.g., an endoscope) that can pass through internal body passages such as the airway or the lumen of the esophagus or colon. This allows for minimally invasive treatment, which can reduce patient mortality and intraoperative and postoperative complications.

[0003] A method for treating pancreatic tissue using endoscopic ultrasound-guided high-frequency ablation is known (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 technique, a small-diameter (e.g., 0.33 mm) conductive wire is inserted through the working channel of an ultrasound-enabled endoscope. RF power is applied to the wire in combination with an external grounded return pad in contact with the patient's skin to coagulate liver and pancreatic tissue. To ablate the lesion, power is applied for 90–120 seconds, and in some cases, the wire must be removed and repositioned. Summary of the Invention

[0004] Most generally, the present invention provides an electrosurgical device having a emitting tip portion for delivering electromagnetic energy to biological tissue, the electrosurgical device being disposed within a catheter. The electrosurgical device is movable relative to the catheter between a deployed position, in which the emitting tip portion is exposed, and a retracted position, in which the emitting tip portion is contained within the catheter. In this manner, the emitting tip portion can be retracted until it is time to use it. This can facilitate insertion of the device through an instrument channel of a surgical scope device. Specifically, when the device is inserted into the instrument channel, the emitting tip portion can be prevented from getting caught in the instrument channel, which could cause damage to the instrument channel and / or the emitting tip portion.

[0005] This configuration may be particularly beneficial for treating tumors of the pancreas, as the device can be positioned adjacent to the duodenal wall with the radiating tip in the retracted position. The radiating tip can then be exposed and penetrated through the duodenal wall to enter the pancreas, where electromagnetic energy can be delivered to ablate the targeted tissue. The radiating tip is sized for insertion into the pancreas. This may provide a fast and accurate alternative to known RF ablation techniques.

[0006] The present invention may be particularly suitable for use in the pancreas, but may also be suitable for use in other difficult treatment sites, such as the lungs and liver.

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

[0008] This configuration allows the radiating tip portion to be retracted into the catheter when not in use. In this manner, the instrument can be manipulated into position with the radiating tip portion in the retracted position to facilitate manipulation of the instrument. Because the radiating tip portion has a smaller outer diameter than the coaxial cable, it is more likely to get caught in the instrument channel of a surgical scope device or in tissue. By keeping the radiating tip portion in the retracted position while the instrument is being manipulated, such snagging of the radiating tip portion can be avoided.

[0009] The electrosurgical device can be moved along the lumen of the catheter using a suitable actuation mechanism. When the electrosurgical device is in the deployed position, all or a portion of the emitting tip portion can protrude beyond the distal end of the catheter. When the electrosurgical device is in the retracted position, the distal needle tip can be positioned within the catheter so that it does not protrude beyond the distal end of the catheter. The electrosurgical device can be moved distally to move the electrosurgical device to the deployed position, and the electrosurgical instrument can be moved proximally to move the electrosurgical device to the retracted position.

[0010] The catheter may be formed by tubing made of 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 polyether block amide (e.g., Pebax®) material. The catheter may be made of or coated with a non-stick material (e.g., PTFE) to prevent tissue from adhering to the catheter. The outer diameter of the catheter may be 2.0 mm or less to fit within the instrument channel of a surgical scope device.

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

[0012] The flexible coaxial cable may be a conventional low-loss coaxial cable connectable at its proximal end to an electrosurgical generator for receiving microwave energy. The coaxial cable may have a center conductor separated from an outer conductor by a dielectric material. The coaxial cable may further include an outer protective sheath to insulate and protect the cable. In some embodiments, the protective sheath is made of 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 coupled to receive microwave energy transmitted along the coaxial cable.

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

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

[0015] The dimensions of the components of the proximal coaxial transmission line may be selected to provide an impedance that is the same as or close to that of the flexible coaxial cable (e.g., about 50 Ω). 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 may facilitate bending of the radiating tip portion.

[0016] The distal needle tip is formed at the distal end of the proximal coaxial transmission line. The distal needle tip may include an emitter structure configured to receive microwave energy from the proximal coaxial transmission line and deliver the energy to the target tissue. The emitter structure may be selected based on the type of energy to be delivered and the desired treatment. For example, the emitter structure may include a monopole or bipole microwave antenna for radiating microwave energy into surrounding tissue to perform tissue ablation. In other examples, the emitter structure may include a pair of RF electrodes configured to deliver radio frequency energy to the target tissue. In such examples, the coaxial cable may be configured to deliver radio frequency (RF) energy to an electrosurgical device, which may enable the electrosurgical device to perform ablation, coagulation, and / or ablation using RF energy. In some examples, the emitter structure may be configured to emit both microwave and radio frequency energy (simultaneously or sequentially).

[0017] As noted above, the outer diameter of the radiating tip portion is smaller than the outer diameter of the coaxial cable. Using a smaller diameter radiating tip portion can reduce the size of the entry hole created when the radiating tip portion is inserted into the target tissue. This can reduce bleeding and speed wound healing. For example, this can reduce the size of the entry hole created in the duodenal wall when the device is inserted into the pancreas. The inventors have also found that such a configuration is beneficial for treating tumors in the liver, where entry hole bleeding can be a problem.

[0018] Additionally, the outer diameter of the radiating tip section may be smaller than that of the coaxial cable, making the radiating tip section more flexible than the coaxial cable. This may make it easier to navigate the distal needle tip to a desired location, for example, when the device needs to be navigated near a sharp bend. Thus, the present invention successfully combines the use of a relatively large outer diameter coaxial cable to reduce the effects of heat loss with the use of a relatively small diameter radiating tip section to improve flexibility and reduce tissue damage during insertion.

[0019] The distal needle tip may be configured to act as a half-wave transformer for delivering microwave energy from the distal needle tip to biological tissue. An advantage of configuring the distal needle tip as a half-wave transformer may be to minimize reflections at interfaces between components, such as between the coaxial cable and the proximal coaxial transmission line, and between the proximal coaxial transmission line and the distal needle tip. The reflection coefficient at the latter interface is typically large due to large impedance variations. The half-wave configuration may minimize these reflections so that the dominant reflection coefficient is that of the interface between the proximal coaxial transmission line and tissue. The impedance of the proximal coaxial transmission line may be selected to be the same as or close to the expected tissue impedance to provide a good match at the frequency of the microwave energy.

[0020] The catheter may include a constricted passage at its distal end, sized to allow passage of the radiating tip portion and prohibit passage of the flexible coaxial cable. In one embodiment, the constricted passage may extend through a plug attached to the distal end of the catheter. The plug may act to prevent tissue and / or fluid from entering the catheter from the treatment site. Additionally, the constricted passage may help guide the radiating tip portion as the device moves between the retracted and deployed positions. This may enable precise positioning of the radiating tip portion, thereby facilitating guidance of the distal needle tip to the target treatment site. The constricted passage may be aligned with the longitudinal axis of the device to center the radiating tip portion about the longitudinal axis. The plug may be made of an insulating material (e.g., PEEK) to avoid short circuits between the plug and the radiating tip portion.

[0021] The plug can cover the opening at the distal end of the catheter; for example, the plug can be a cap at the distal end of the catheter. The constricted passage can be sized to allow the radiating tip portion to pass through but not the larger diameter coaxial cable. In this manner, the constricted passage can act to limit distal movement of the electrosurgical device along the lumen. This can prevent the coaxial cable from being pushed beyond the distal end of the catheter, preventing injury caused by the larger diameter of the coaxial cable.

[0022] In some embodiments, the constricted passageway may include a lip for removing biological tissue from the emitting tip portion as the electrosurgical device moves from the deployed position to the retracted position. For example, the lip may be configured to scrape tissue from the emitting tip portion as the emitting tip portion is retracted into the catheter. This may prevent tissue from becoming entrapped within the catheter, which could contaminate the catheter or cause malfunction of the instrument (e.g., by restricting movement of the electrosurgical device along the lumen). The lip may be located at the distal opening of the passageway, for example, the lip may be located around the distal opening of the passageway. In this manner, tissue may be prevented from entering the passageway. The lip may be a sharp edge around the opening of the passageway.

[0023] The distal surface of the catheter may be rounded. For example, the distal end surface of the plug may be rounded, e.g., hemispherical or dome-shaped. A rounded surface may avoid sharp edges around the distal end of the catheter. This may facilitate insertion of the instrument into the working channel of a surgical scope instrument. In particular, it may facilitate maneuvering the instrument through bends in the working channel.

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

[0025] 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, a lip or step may occur at the interface between the distal needle tip and the proximal coaxial transmission line. By making the constricted passage longer than the distal needle tip, the lip at the interface between the distal needle tip and the proximal coaxial transmission line can be positioned inside the constricted passage when the device is in the retracted position. In this way, the lip is prevented from catching on the proximal opening of the constricted passage when the device is moved from the retracted position to the deployed position.

[0026] The proximal opening of the passageway in the plug may be flared outward, e.g., the diameter of the proximal opening may increase in the proximal direction. In this manner, the proximal opening of the passageway may act as a funnel to guide the emitting tip portion into the passageway. This may facilitate moving the electrosurgical device along the lumen and prevent the emitting tip portion from getting caught in the proximal opening of the passageway.

[0027] In some embodiments, the plug can include a body portion disposed inside the catheter, the body portion including protrusions for securing the plug to the catheter. In this manner, the plug can be attached to the distal end of the catheter without the use of adhesive. However, in some cases, adhesive may be used to more securely secure the plug to the catheter. The protrusions may be, for example, bulges or barbs positioned to press outward against the catheter and hold the plug in place within the catheter. The plug can be attached to the distal end of the catheter by pushing the body portion of the plug into the catheter. In this manner, a "push-fit" connection can be formed between the plug and the distal end of the catheter.

[0028] The distal needle tip may include a sharp point at its distal end. The sharp point may be made of a hard, insulating material such as zirconia or ceramic. Zirconia may be particularly suitable for use as a sharp point because it is a rigid, dielectric material and can be tapered. The sharp point may aid in tissue penetration and facilitate insertion of the emitting tip portion into the target tissue.

[0029] The distal needle tip may include a distal dielectric sleeve around the central conductive element, and the tip may be secured in a lumen at the distal end of the distal dielectric sleeve. The tip may include a body disposed at the distal end of the distal dielectric sleeve, and the tip body may include a protrusion for securing the body within the lumen. In this manner, the tip may be retained within the lumen at the distal end of the distal dielectric sleeve. By providing the tip body in the lumen of the distal dielectric sleeve, the tip can be securely held in place. The protrusion may be, for example, a bulge or barb configured to press outward against the wall of the lumen to hold the body in place within the lumen. The tip can be attached to the distal end of the distal dielectric sleeve by forcing the distal tip body into the lumen. In this manner, a "force-fit" connection may be formed between the tip and the distal dielectric sleeve. This configuration may allow the tip to be attached to the distal dielectric sleeve without adhesive. However, in some cases, adhesive may be used to more securely secure the tip.

[0030] The tip may be made of a dielectric material that has a higher stiffness than the distal dielectric sleeve, which may allow the tip to be sharper and facilitate piercing of tissue.

[0031] The proximal coaxial transmission line can include an inner conductor separated from an outer conductor by a dielectric sleeve, the inner conductor including a distal portion that protrudes beyond the distal end of the outer conductor, and the distal needle tip includes a portion of the distal portion of the inner conductor. Thus, the distal dielectric sleeve can be around the inner conductor forming the central conductive element.

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

[0033] In some embodiments, the tip can have a proximal portion tapered at a first longitudinal angle and a distal portion tapered at a second longitudinal angle, the first angle being less than the second angle. Increasing the angle of taper at the distal portion of the tip can reduce the fragility of the tip, thereby reducing the likelihood of particulates being shed from the tip and remaining in the body.

[0034] The outer conductor of the proximal coaxial transmission line may be made of nitinol. For example, the outer conductor may be formed of a nitinol tube. The inventors have found that nitinol has sufficient longitudinal stiffness to transmit force through the duodenal wall. Furthermore, the flexibility of nitinol can facilitate bending of the radiating tip portion, thereby enabling the device to be guided through narrow, curved passages. Therefore, forming the outer conductor from nitinol may facilitate the use of devices to treat pancreatic tumors.

[0035] The radiating tip portion may be secured to the coaxial cable by a collar attached over the junction therebetween, the collar having a rounded distal surface. The collar may be disposed at the interface between the distal end of the coaxial cable and the proximal end of the proximal coaxial transmission line. The distal surface of the collar may be the forward-facing surface of the collar, i.e., the surface facing toward the distal end of the instrument. By providing a collar with a rounded distal surface, sharp edges may be avoided at the interface between the coaxial cable and the proximal coaxial transmission line. This may reduce friction between the electrosurgical device and the catheter as the electrosurgical device is moved along the lumen. This may facilitate moving the electrosurgical device along the lumen, for example, when the instrument is bowed (e.g., when the catheter has a bend).

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

[0037] The length of the radiating tip section can be 140 mm or more. Coaxial cables commonly used in electrosurgical instruments (e.g., Sucoform 86 coaxial cable) often have a thick, tinned exterior to allow longitudinal movement of the cable. However, this makes the coaxial cable relatively stiff, requiring a large amount of force to bend the coaxial cable. This can create significant friction when moving the device through the bends in the catheter, which can hinder precise control of the device. Because the radiating tip section can have greater flexibility compared to the coaxial cable, having a long radiating tip section can facilitate bending the device near its distal end. Having a radiating tip section of 140 mm or more avoids the need to move the coaxial cable through the bent distal section of the catheter. This may facilitate deployment of the radiating tip portion, for example, if the distal portion of the catheter is deflected. This configuration may be particularly beneficial for use in the pancreas, where the distal portion of the device may need to be deflected.

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

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

[0040] The proximal portion of the coaxial cable can be secured to a rigid stiffening element. The stiffening element can serve to increase the longitudinal stiffness of the proximal portion of the coaxial cable. This can facilitate applying a force (e.g., a pushing or pulling force) to the proximal end of the coaxial cable to move the electrosurgical device along the lumen. This can improve control of the position of the electrosurgical device within the lumen. The stiffening element can be disposed on an outer surface of the proximal portion of the coaxial cable.

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

[0042] The proximal portion of the lumen may have a larger diameter than the distal portion of the lumen to accommodate the proximal portion of the coaxial cable. The outer diameter of the proximal portion of the coaxial cable may be larger than the outer diameter of the distal portion of the coaxial cable due to the stiffening element. Having a catheter with a larger diameter proximal portion may allow the proximal portion of the coaxial cable to slide within the catheter without additional friction caused by the stiffening element.

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

[0044] In some cases, the tapered portion may define the distal opening of the catheter, where the diameter of the distal opening is the second, smaller diameter. In this way, when the electrosurgical device is in the deployed position, the emitting tip portion may protrude through the distal opening of the tapered portion. Thus, the tapered portion may perform a function similar to the plug described above. The tapered portion may be used as a substitute for a plug at the distal end of the catheter, for example, to simplify the structure of the device. In some cases, the plug may be combined with the tapered portion, e.g., a plug. may be attached to the distal opening of the tapered portion.

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

[0046] According to a second aspect of the present invention, there is provided a handpiece for controlling movement of an electrosurgical device along a lumen of a catheter, the handpiece comprising: a first portion having a connector for connecting a distal end of the handpiece to an instrument port of a surgical scope device; a second portion connected to the first portion and movable longitudinally of the first portion, the second portion having a holder for holding a proximal end of the catheter, whereby relative movement between the second portion and the first portion is configured to control the length of the catheter extending from the distal end of the handpiece; and a third portion connected to the second portion and movable longitudinally of the second portion, the third portion having a coaxial connector configured to receive a proximal end of a coaxial cable carried within the lumen of the catheter, whereby relative movement between the third portion and the second portion is configured to control the relative position of the coaxial cable within the catheter.

[0047] The handpiece of the second aspect of the present invention can be used with the electrosurgical instrument of the first aspect of the present invention to control the position of the electrosurgical device within the catheter. An independent aspect of the present invention can provide an electrosurgical apparatus including the electrosurgical instrument of the first aspect and the handpiece of the second aspect configured to control the position of the electrosurgical device within the catheter.

[0048] Advantageously, the handpiece of the second aspect of the present invention allows the length of the catheter to be adjusted independently of the position of the electrosurgical device within the catheter. In this manner, the length of the catheter can be adjusted to fit within the instrument channel of the surgical scope device.

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

[0050] The proximal end of the coaxial cable can be connected to the coaxial connector of the third section. In this manner, the position of the coaxial cable (and therefore the electrosurgical device) can be fixed relative to the third section. For example, the coaxial cable can include a connector at its proximal end configured to mate with the coaxial connector of the third section. Alternatively, the coaxial cable can be directly connected to the coaxial connector of the third section, for example, via a soldered and / or welded electrical connection. The coaxial connector of the third section can be fixed to the body of the third section, for example, via screws or adhesive. The coaxial connector can 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.

[0051] The first part is connected to the input port of the instrument channel of the surgical scope device. The first portion serves to secure the handpiece to the surgical device. The connector of the first portion may be configured to mate with a corresponding connector of the surgical scope device. For example, the connector may be a Luer connector, which may enable a leak-tight connection to be formed between the handpiece and the instrument channel. The connector may include a mechanism for securing the handpiece to the surgical device, for example, via a clamp or threaded connection.

[0052] During use, the second portion can be moved relative to the first portion to adjust the length of the catheter that protrudes from the handpiece. Because the first portion is fixed relative to the instrument channel of the surgical scope device and the catheter is fixed relative to the second portion, moving the second portion relative to the first portion can control the length of the catheter within the instrument channel. In this manner, the length of the catheter can be adjusted to fit the instrument channel.

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

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

[0055] The second section may include a limiter movable in the longitudinal direction of the second section, the limiter configured to limit the movement of the third section relative to the second section. Thus, the position of the limiter can be adjusted to set a desired range of motion of the third section relative to the second section. This can help limit the extent to which the emitting tip section can be exposed beyond the distal end of the catheter. This can prevent the emitting tip section from being accidentally pushed too far and damaging healthy tissue. The limiter may have, for example, a stop surface positioned to abut the third section as the third section moves distally to prevent further distal movement of the third section. The limiter may be a slider provided on the surface of the second section. The limiter may include a fixing mechanism (e.g., a screw or clamp) for fixing the limiter at a desired position along the longitudinal direction of the second section.

[0056] In some embodiments, the second portion may include a first set of markers positioned to indicate the maximum range of motion of the electrosurgical device along the lumen based on the position of the limiter relative to the first set of markers. In this manner, a desired range of motion of the electrosurgical device along the lumen can be set by moving the limiter to a corresponding marker on the second portion. This may facilitate setting the desired range of motion even when the user has difficulty determining the exact position of the emitting tip portion. For example, the markers may indicate the length of the emitting tip portion that protrudes from the catheter when the third portion abuts the limiter.

[0057] In some embodiments, the first portion is a position of the second portion relative to the second marker set. The catheter may include a second set of markers positioned to indicate the length of the catheter within the instrument channel based on the position of the catheter in the first portion. In this manner, a user can adjust the length of the catheter by moving the second portion to a corresponding marker on the first portion. This can facilitate adjusting the length of the catheter to a desired length even when it is difficult to determine the length of the catheter while it is in the instrument channel.

[0058] In some embodiments, the first and second portions may be nested together, with the second portion being slidable longitudinally relative to the first portion. For example, the first and second portions may have concentric tubular bodies, with one portion being slidably disposed within the other. In some cases, the second and third portions may be nested together, with the third portion being slidably disposed longitudinally relative to the second portion. For example, the first and second portions may have concentric tubular bodies, with one portion being slidably disposed within the other. The nested configuration may provide a compact design for the handpiece.

[0059] The electrosurgical instruments and handpieces discussed above may be part of a complete electrosurgical system. For example, the electrosurgical system may include an electrosurgical generator configured to supply microwave and / or radio frequency energy, a surgical scope device having a flexible insertion cord for insertion into a patient's body, the flexible insertion cord having an instrument channel extending the length thereof, an electrosurgical instrument according to a first aspect of the present invention, the electrosurgical instrument being sized to fit within the instrument channel, and a handpiece according to a second aspect of the present invention, the handpiece having a proximal end of a catheter of the electrosurgical instrument held in a holder and a proximal end of a coaxial cable of the electrosurgical instrument received in a coaxial connector that is connected to the electrosurgical generator to receive the microwave and / or radio frequency energy.

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

[0061] As used herein, the term "inner" means radially closer to the center (e.g., axis) of the equipment channel and / or coaxial cable, and the term "outer" means radially farther from the center (axis) of the equipment channel and / or coaxial cable.

[0062] As used herein, the term "conductive" means electrically conductive, unless the context dictates otherwise.

[0063] As used herein, the terms "proximal" and "distal" refer to the ends of an elongate probe. In use, the proximal end is closer to a generator for supplying RF and / or microwave energy, while the distal end is further from the generator.

[0064] As used herein, "microwave" can be used broadly to refer to the frequency range of 400 MHz to 100 GHz, but preferably refers to the range of 1 GHz to 60 GHz. Preferred spot frequencies of microwave EM energy include 915 MHz, 2.45 GHz, 3.3 GHz, 5.8 GHz, 10 GHz, 14.5 GHz, and 24 GHz. z may be preferred. The device may provide energy at more than one of these microwave frequencies.

[0065] The term "radio frequency" or "RF" is sometimes used to refer to frequencies between 300 kHz and 400 MHz.

[0066] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0067] [Figure 1] 1 is a schematic diagram illustrating an electrosurgical system according to an embodiment of the present invention. [Figure 2] 1A and 1B show schematic cross-sectional views of an electrosurgical instrument according to an embodiment of the present invention, where in 1A the electrosurgical device of the instrument is in a retracted position, and in 1B the electrosurgical device of the instrument is in a deployed position. [Figure 3a] FIG. 2c is a perspective view of the electrosurgical instrument of FIGS. 2a and 2b. [Figure 3b] FIG. 2c is a perspective view of the electrosurgical instrument of FIGS. 2a and 2b, with the catheter of the instrument removed to reveal the internal structure of the instrument. [Figure 4] FIG. 2c is a perspective view of the electrosurgical instrument of FIGS. 2a and 2b. [Figure 5] 1 is a schematic side view of an electrosurgical device that is part of an electrosurgical instrument according to an embodiment of the present invention; FIG. [Figure 6] 1 is a schematic side view of an electrosurgical device that is part of an electrosurgical instrument according to an embodiment of the present invention; FIG. [Figure 7] 1 shows a schematic cross-sectional view of a distal needle tip of an electrosurgical instrument according to an embodiment of the present invention. [Figure 8] 1 shows a schematic diagram of a distal needle tip of an electrosurgical instrument according to an embodiment of the present invention. [Figure 9] 10a and 10b are schematic cross-sectional views illustrating the deformation of respective embodiments of an electrosurgical instrument when inserted through a recurved instrument channel. [Figure 10] 1 shows a schematic cross-sectional view of a handpiece according to an embodiment of the present invention. [Figure 11]11 shows a perspective view of the handpiece of FIG. 10, and in FIG. 11 some of the components of the handpiece are omitted to show the internal structure of the handpiece. [Figure 12] FIG. 11 shows a perspective view of the handpiece of FIG. 10. [Figure 13] 11a and 11b show plan views of the handpiece of FIG. 10 with the distal needle in the retracted and extended (deployed) positions, respectively. [Figure 14a] 1 is a cross-sectional view of a catheter that is part of an electrosurgical instrument that is an embodiment of the present invention. [Figure 14b] 1 is a cross-sectional view of a catheter that is part of an electrosurgical instrument that is another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0068] Detailed explanation, further options and preferences FIG. 1 is a schematic diagram of an electrosurgical ablation system 100 capable of supplying microwave and / or radio frequency energy to the distal end of an invasive electrosurgical instrument. The system 100 includes a generator 102 for controllably supplying microwave 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 a received reflected signal returned from the instrument to determine an appropriate power level to supply. For example, the generator may be configured to calculate the expected impedance at the distal end of the instrument to determine the optimal power level to supply.

[0069] The generator 102 is connected to a handpiece 106 by an interface cable 104. In other embodiments (not shown), the handpiece 106 may be connected to a syringe via fluid flow lines, for example, when it is desired to deliver fluid to the distal end of the electrosurgical instrument. It may also be connected to a fluid supply device such as a pump.

[0070] The handpiece 106 houses an instrument control mechanism operable to control longitudinal (back and forth) movement of the electrosurgical instrument. The handpiece 106 may also house a control mechanism (e.g., a trigger) for actuating one or more control wires or push rods, as needed. Examples of handpieces are described in further detail below with reference to FIGS. 10-12. The function of the handpiece is to aggregate inputs from the generator 102 and any other inputs into an integrated flexible instrument cable that exits the distal end of the handpiece 106 and is sized to be transported through the instrument channel of a surgical scope device.

[0071] The handpiece 106 is connected to an input port 128 of a surgical scope device 114. The surgical scope device 114 includes a body 116 having several input ports and an output port from which an instrument cord 120 extends. The instrument cord 120 includes an exterior covering surrounding multiple lumens. The multiple lumens transport various components from the body 116 to the distal end of the instrument cord 120. One of the multiple lumens is an instrument channel through which an instrument cable extends. 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 an ultrasound signal channel for transmitting ultrasound signals. The body 116 may be equipped with an eyepiece 122 or other imaging device that allows viewing of the distal end.

[0072] An ultrasound endoscopic device typically includes an ultrasound transducer at the distal tip of an instrument cord, beyond the exit aperture of an ultrasound signal channel. Signals from the ultrasound transducer may be transmitted by a suitable cable 126 back down the instrument cord to a processor 124, which may generate images in a known manner. The instrument channel may be molded into the instrument cord so that the instrument exiting the instrument channel is directed into the field of view of the ultrasound system, providing information regarding the position of the instrument at the target site.

[0073] An integrated flexible instrument cable exits the distal end of handpiece 106 and is received within an instrument channel in instrument cord 120 of surgical scope device 114. The integrated flexible instrument cable passes through the instrument channel of surgical scope device 114 and has a distal assembly 118 (not drawn to scale in FIG. 1 ) shaped to protrude (e.g., into the patient) at the distal end of instrument cord 120.

[0074] The structure of the distal end assembly 118, described below, may be designed specifically for use with an endoscopic ultrasound (EUS) device, thereby allowing the maximum outer diameter of the distal end assembly 118 to be 1.2 mm or less, e.g., 1.0 mm or less, and the length of the electrosurgical instrument to be 1.2 m or more.

[0075] It is desirable to be able to control the position of at least the distal end of instrument cord 120. Body 116 may include a control actuator mechanically coupled to the distal end of instrument cord 120 by one or more control wires (not shown) extending through instrument cord 120. The control wire may move within the instrument channel or may move within its own dedicated channel. The control actuator may be a lever or rotatable knob, or any other known catheter manipulation device. Manipulation of instrument cord 120 may be software-assisted, for example, using a virtual three-dimensional map combined with computed tomography (CT) images.

[0076] An electrosurgical instrument 200 according to an embodiment of the present invention is illustrated in Figures 2a, 2b, 3a, 3b, and 4. Electrosurgical instrument 200 includes an integrated instrument cable comprising an electrosurgical device 202 disposed within a catheter 204. Catheter 204 is The electrosurgical device 200 defines a lumen in which the electrosurgical device 202 is received and along which the electrosurgical device 202 is movable. The electrosurgical device 202 is movable along the catheter between a retracted position, shown in FIG. 2a, and a deployed position, shown in FIG. 2b. FIGS. 2a and 2b show schematic cross-sectional side views of the electrosurgical device 200. FIG. 3a shows a perspective view of the device 200 with the catheter 204 displayed as transparent for purposes of illustration to show the electrosurgical device 202 inside the catheter 204. FIG. 3b shows a perspective view of the device 200 with the catheter 204 omitted for purposes of illustration. FIG. 4 shows a perspective view of the electrosurgical device 202 in the deployed position.

[0077] Electrosurgical device 202 is shown in further detail in Figures 5 and 6. Electrosurgical device 202 includes a flexible coaxial cable 206 and a radiating tip portion 208 connected to the distal end of coaxial cable 206. Coaxial cable 206 may be a conventional flexible 50 Ω coaxial cable suitable for transmitting microwave and radio frequency energy. The coaxial cable includes a center conductor and an outer conductor separated by a dielectric material. Coaxial cable 206 is connectable at its proximal end to a generator, such as generator 102, for receiving microwave and / or radio frequency energy.

[0078] The radiating tip section 208 includes a proximal coaxial transmission line 210 and a distal needle tip 212 formed at the distal end of the proximal coaxial transmission line 210. The proximal coaxial transmission line 210 is electrically connected to the distal end of the coaxial cable 206 to receive electromagnetic energy from the coaxial cable 206 and transmit the electromagnetic energy to the distal needle tip 212. The distal needle tip 212 is configured to deliver the received electromagnetic energy to the target biological tissue. In the illustrated embodiment, the distal needle tip 212 is configured as a half-wave transformer to deliver microwave energy to the target biological tissue to ablate the target tissue.

[0079] An 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 secured to the coaxial cable 206 via a collar 216 that is attached over the junction between the coaxial cable 206 and the radiating tip portion 208. The collar 216 is made of a conductive material (e.g., brass) and electrically connects the outer conductor of the coaxial cable 206 to the outer conductor 218 of the proximal coaxial transmission line 210. The outer conductor 218 is formed from a nitinol tube.

[0080] Collar 216 includes a substantially cylindrical body 219 that is attached to the distal end of coaxial cable 206 and electrically connected to the outer conductor of coaxial cable 206. Collar 216 further includes a distal portion 220 that extends from body 219 of collar 216 to the proximal end of outer conductor 218 of proximal coaxial transmission line 210. Distal portion 220 of collar 216 includes a rounded distal surface, which may reduce friction between electrosurgical device 202 and catheter 204 as electrosurgical device 202 moves along catheter 204 by eliminating sharp edges at the interface between coaxial cable 206 and radiating tip portion 208. This may also facilitate moving electrosurgical device 202 along catheter 204 when catheter 204 is deflected.

[0081] The radiating tip portion 208 has a smaller outer diameter than the coaxial cable 206. This allows the radiating tip portion 208 to be more flexible than the coaxial cable 206, which may make it easier to bend the radiating tip portion 208 and / or navigate the radiating tip portion to a difficult treatment site. Reducing the outer diameter of the radiating tip portion 208 also reduces the size of the insertion opening created when the radiating tip portion 208 is inserted into tissue, thereby minimizing bleeding and promoting healing. Preferably, the radiating tip portion has an outer diameter of 1.2 mm or less, such as 1.0 mm or 0.9 mm. The coaxial cable 206 may have an outer diameter of approximately 2.0 mm.

[0082] Catheter 204 is a flexible tube made of an insulating material (e.g., PEEK or PTFE). Catheter 204 is sized for insertion into the working channel of a surgical scope instrument. Catheter 204 defines a lumen within which electrosurgical device 202 is received and along which electrosurgical device 202 is movable.

[0083] A plug 222 is attached to the distal end of the catheter 204. The plug 222 has a body portion 224 that is disposed inside the distal end of the catheter 204. The body portion 224 includes barbs (or bulges) 226 disposed on the exterior surface of the body portion 224, which form an interference fit with the catheter 204 to secure the plug 222 to the distal end of the catheter 204. In this manner, the plug 222 can be secured to the distal end of the catheter 204 without the need for adhesive (although adhesive may be used to more securely secure the plug 222 to the catheter 204). The distal surface 228 of the plug 222, i.e., the surface exposed at the distal end of the catheter 204, is rounded. The rounded distal surface 228 of the plug 222 serves to eliminate sharp edges around the distal end of the catheter 204. This may facilitate easier insertion of electrosurgical device 200 along the instrument channel of a surgical scope device by reducing friction between catheter 204 and the instrument channel at the distal end of catheter 204. The plug may be made of PEEK or some other insulating material.

[0084] Plug 222 has a longitudinal passageway 230 defined therethrough. Passageway 230 is sized to allow radiating tip portion 208 to pass through passageway 230 but to prevent coaxial cable 206 from passing through passageway 230. In this manner, electrosurgical device 202 can be advanced along catheter 204 to cause radiating tip portion 208 to pass through the passageway, thereby causing a portion of radiating tip portion 208 to protrude beyond the distal end of catheter 204 (e.g., as shown in FIG. 2b).

[0085] Passageway 230 includes a proximal opening 232 inside catheter 204 at the proximal end of body portion 224. A distal opening 234 of passageway 230 is located on a distal face 228 of plug 222. When electrosurgical device 202 is in the deployed position (e.g., FIG. 2b), emitting tip portion 208 protrudes through distal opening 234 of passageway 230. The length of passageway 230 is greater than the length of distal needle tip 212; i.e., the distance between proximal opening 232 and distal opening 234 of passageway 230 is greater than the length of distal needle tip 212. In this manner, as shown in FIG. 2a, when electrosurgical device 202 is in the retracted position, distal needle tip 212 can be completely housed within passageway 230 of plug 222. Specifically, when electrosurgical device 202 is in the retracted position, a lip 236 formed by the distal end of outer conductor 218 can be located inside passageway 230. This prevents lip 236 from getting caught in proximal opening 232 of passageway 230 as electrosurgical device 202 moves from the retracted position to the deployed position.

[0086] Lip 236 of outer conductor 218 is chamfered, e.g., beveled, to further prevent lip 236 from getting caught in proximal opening 232 of passageway 230. Proximal opening 232 of the passageway 230 flares outward, i.e., the diameter of opening 232 increases in the proximal direction. In this manner, flared proximal opening 232 acts to funnel radiating tip portion 208 into the passageway, preventing radiating tip portion 208 from getting caught in proximal opening 232 and facilitating movement of radiating tip portion 208 within passageway 230.

[0087] The passageway 230 serves to guide the emitting tip portion 208 as the electrosurgical device 202 moves between the retracted and deployed positions. As it is moved within the passage 230 , it is centered about the longitudinal axis of the catheter 204 such that the passage 230 acts to center the radiating tip portion 208 .

[0088] 2a, electrosurgical device 202 is in the retracted position, with distal needle tip 212 located within passageway 230 of plug 222. This means that emitting tip portion 208 does not protrude from catheter 204. Thus, in this configuration, emitting tip portion 208 is protected by catheter 204 and plug 222. Electrosurgical instrument 200 may be inserted into an instrument channel of a surgical scope device and guided into position with electrosurgical device 202 in the retracted position. This may facilitate easier insertion of electrosurgical instrument 200 into the instrument channel, as emitting tip portion 208 will not get caught in the instrument channel.

[0089] Once the electrosurgical instrument 200 has been navigated to the desired location, the electrosurgical device 202 may be moved to a deployed position. This may be accomplished by moving the electrosurgical device 202 distally along the catheter 204 from the retracted position shown in FIG. 2a until the emitting tip portion 208 protrudes from the distal opening 234 of the passageway 230 in the plug 222. The electrosurgical device 202 may be moved until it reaches the deployed position shown in FIG. 2b. Once the electrosurgical device 202 protrudes from the distal opening 234 of the passageway 230, the emitting tip portion 208 may be inserted into biological tissue. Once the distal needle tip 212 reaches the target treatment site (e.g., a tumor), microwave energy may be delivered to the distal needle tip to ablate the target tissue.

[0090] Once the target tissue has been treated, the electrosurgical device 202 may be returned to the retracted position so that the emitting tip portion 208 is no longer exposed. This movement is accomplished by moving the electrosurgical device 202 proximally along the catheter 204.

[0091] A sharpened lip 238 is provided around the distal opening 234 of the passageway 230. The sharpened lip 238 serves to scrape away any tissue or blood adhering to the emitting tip portion 208 as the electrosurgical device 202 is moved from the deployed position to the retracted position, thereby preventing tissue and / or blood from being drawn into the catheter 204 as the emitting tip portion 208 is retracted within the catheter 204, which could contaminate the catheter 204 or interfere with movement of the electrosurgical device 202 within the catheter.

[0092] The structure of the radiating tip portion 208 of the electrosurgical device 202 will now be described in further detail with reference to Figures 5 and 6. For purposes of illustration, the outer conductor 218 has been omitted from Figure 6 to reveal the internal structure of the radiating tip portion 208. Also, for purposes of illustration, a section of the proximal coaxial transmission line 210 has been omitted from Figures 5 and 6, as indicated by dashed line 502.

[0093] The proximal coaxial transmission line 210 includes a proximal dielectric sleeve 504 disposed around the inner conductor 214. The outer conductor 218 is formed on the outer surface of the proximal dielectric sleeve 504. A distal dielectric sleeve 506 is disposed around the distal portion of the inner conductor 214 to form the distal needle tip 212. The distal dielectric sleeve 506 is made of a different dielectric material than the proximal dielectric sleeve 504. In one embodiment, the proximal dielectric sleeve 504 may be made of PTFE (e.g., a PTFE tube), and the distal dielectric sleeve may be made of PEEK. A distal portion of the outer conductor 218 overlaps a proximal portion of the distal dielectric sleeve 506. In this manner, the distal portion of the proximal coaxial transmission line 210 includes the proximal portion of the distal dielectric sleeve 506. The materials of the proximal and distal dielectric sleeves and the length of the overlap between the outer conductor 518 and the distal dielectric sleeve 506 may be selected to adjust the electrical length of the radiating tip portion 208 to assist in impedance matching with the target tissue.

[0094] The outer conductor 218 may be made of nitinol, which is flexible and provides sufficient longitudinal stiffness to penetrate tissue (e.g., the duodenal wall). The inner conductor is a silver-plated stainless steel core. The stainless steel core provides additional stiffness to the radiating tip section 208, while the silver plating may increase the conductivity of the inner conductor 214 to reduce losses in the radiating tip section 208.

[0095] A dielectric spacer 508 is attached to the junction between the radiating tip portion 208 and the coaxial cable 206. The dielectric spacer 508 is disposed inside the collar 216 and is attached around the inner conductor 214. In this manner, the dielectric spacer 508 is disposed between the inner conductor 214 and the collar 216. This increases the breakdown distance between the inner conductor 214 and the collar 216 at the junction between the coaxial cable 206 and the radiating tip portion 208. This may improve the electrical safety of the device at the junction. The dielectric spacer 508 may be, for example, a PTFE washer or a washer made of another suitable insulating material.

[0096] As described above, the distal needle tip 212 is configured as a half-wave transformer for delivering microwave energy to tissue. Therefore, when microwave energy is delivered to the distal needle tip 212, the distal needle tip 212 can radiate the microwave energy into surrounding tissue. The distal needle tip 212 includes a tip 510 at its distal end to facilitate insertion of the radiating tip portion 208 into the target tissue. The tip 510 is made of a dielectric material that has a higher rigidity than the distal dielectric sleeve 506. This may allow the tip 510 to be sharper, and the higher rigidity may facilitate sharpening of the tip 510. For example, the tip 510 may be made of zirconia.

[0097] FIG. 7 shows a more detailed view of the tip 510 attached to the distal end of the distal dielectric sleeve 506. The tip 510 includes a tapered portion 702 that tapers to a fine point and functions to penetrate tissue. The tip also includes a body 704 that extends from the proximal end of the tapered portion 702 and is received within a lumen at the distal end of the distal dielectric sleeve. The body 704 of the tip 510 includes a protrusion (or bulge) 706 that forms an interference fit with the wall of the lumen to retain the body 704 within the lumen. In this manner, a “push-fit” connection may be formed when the body 704 is inserted into the lumen. This may allow the tip 510 to be attached to the distal dielectric sleeve 506 without adhesive. This may also facilitate replacement of the tip 510, for example, if the tip 510 is damaged.

[0098] FIG. 8 illustrates another example of a tip 802 attached to the distal end of the distal dielectric sleeve 506. The tip 802 includes a body 804 disposed within the lumen at the distal end of the distal dielectric sleeve 506. The body 804 includes a protrusion 806 for securing the body 804 within the lumen. The tip 802 further includes a tapered portion 808 that protrudes from the lumen of the distal dielectric sleeve 506 and tapers to a micropoint for penetrating tissue. The tapered portion 808 includes a proximal portion 810 tapered at a first angle relative to the longitudinal direction and a distal portion 812 tapered at a second, larger angle relative to the longitudinal direction. In this manner, the tip 802 can be described as "bi-angled." The micropoint of the tip 802 is formed by the distal portion 812. By making the taper angle of the distal portion 812 greater than the taper angle of the proximal portion 810, the length of the tapered section 808 can be shortened, which makes the tip 802 less likely to break and reduces the risk of breaking off the small point of the tip 802.

[0099] In some embodiments (not shown), the tip may be made of the same material as the distal dielectric sleeve, e.g., the tip may be integrally formed with the distal dielectric sleeve. The concept of using a bi-angled tip can be applied regardless of whether the tip is integrally formed with the distal dielectric sleeve or is separately formed. In some embodiments (not shown), the proximal and distal dielectric sleeves may be replaced by a single dielectric sleeve, e.g., the dielectric material of the proximal coaxial transmission line and the distal needle tip may be the same.

[0100] Figure 9a shows a cross-sectional view of an electrosurgical instrument 900 in accordance with an embodiment of the present invention, with a distal portion of the instrument 900 being deflected. Figure 9b shows a cross-sectional view of an electrosurgical instrument 902 in accordance with another embodiment of the present invention, with a distal portion of the instrument 902 being deflected.

[0101] Electrosurgical instruments 900 and 902 have a configuration similar to electrosurgical instrument 200 described above. Electrosurgical instrument 900 includes a catheter 904 having an electrosurgical device 906 disposed therein. Electrosurgical device 906 includes a coaxial cable 908 having a radiating tip portion 910 disposed at the distal end of coaxial cable 908. Electrosurgical device 906 is movable along catheter 904 between a retracted position, in which radiating tip portion 910 is located within catheter 904, and a deployed position, in which radiating tip portion 910 protrudes from the distal end of catheter 904. In the configuration shown in FIG. 9a, electrosurgical device 906 is in the deployed position.

[0102] Similarly, electrosurgical instrument 902 includes an electrosurgical device 912 disposed within a catheter 914. Electrosurgical device 912 includes a coaxial cable 916 and a radiating tip portion 918 at the distal end of coaxial cable 916. Electrosurgical device 912 is movable along catheter 914 between a retracted position, in which radiating tip portion 918 is located within catheter 914, and a deployed position, in which radiating tip portion 918 protrudes from the distal end of catheter 914. In the configuration shown in FIG. 9b, electrosurgical device 912 is in the deployed position.

[0103] In Figure 9a, the distal portion 920 of the catheter 904 is bowed, i.e., the distal portion 920 of the catheter 904 is curved. As can be seen in Figure 9a, the distal portion of the coaxial cable 908 is located at the distal portion 920 of the catheter 904, and the distal portion of the coaxial cable 908 is also curved. Therefore, to move the electrosurgical device 906 between the retracted position and the deployed position (shown in Figure 9a), the distal portion of the coaxial cable 908 must be bent. For example, when the electrosurgical device 906 is moved from the retracted position to the deployed position, the distal portion of the coaxial cable 908 must be pushed through the curved distal portion 920 of the catheter 904. When the electrosurgical device 906 is moved from the deployed position to the retracted position, the distal portion of the coaxial cable 908 must be straightened as it is withdrawn from the curved distal portion 920 of the catheter 904.

[0104] Bending and straightening the coaxial cable 908 can require a large force due to the stiffness of the coaxial cable 908. Coaxial cables used in conventional electrosurgical devices, such as Sucoform 86 coaxial cable, have a relatively stiff (e.g., heavily tinned) exterior. While such an exterior may facilitate actuation of the instrument along a straight path, a large force may be required to bend the cable. Consequently, when the distal portion of the catheter 904 is deflected, a large force may be required to apply to the electrosurgical device 906 to move the electrosurgical device 906 between the retracted and deployed positions. This can increase friction between the coaxial cable 908 and the catheter 904 at the bend 920, thereby reducing the precision with which the position of the radiating tip section 910 can be controlled.

[0105] The radiating tip portion 918 of the electrosurgical device 912 (FIG. 9b) is longer than the radiating tip portion 910 of the electrosurgical device 906 (FIG. 9a). As a result, if the distal portion 922 of the catheter 914 is curved (e.g., bowed, as shown in FIG. 9b), it may not be necessary to move the coaxial cable 916 through the curved portion 922 of the catheter 914 when moving the electrosurgical device 906 to the deployed position. Because the radiating tip section 918 has a smaller diameter than the coaxial cable and does not have a rigid outer sheath, the radiating tip section 918 may be more flexible than the coaxial cable 916. Therefore, only a relatively small force may be required to bend the radiating tip section 918 when moving the radiating tip section 918 through the curved distal section 922 of the catheter 914.

[0106] 9b, by making the radiating tip portion 918 sufficiently long, the distal end of the coaxial cable 916 does not enter the curved distal section 922 of the catheter 914 when the electrosurgical device 912 is in the deployed position. Therefore, the distal end of the coaxial cable 916 does not need to bend when the electrosurgical device 912 is moved between the retracted position and the deployed position. Preferably, the radiating tip portion may be 140 mm or longer, thereby ensuring that the coaxial cable 916 does not enter the curved portion of the catheter 914 when the electrosurgical device 912 is in the deployed position.

[0107] 9b may therefore reduce friction between the electrosurgical device 912 and the catheter 914 as the electrosurgical device 912 moves along the catheter 914. This may allow for greater control over the position of the emitting tip portion 918.

[0108] The electrosurgical device 912 further includes an outer sheath 924 disposed around a 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 curved distal portion 922 of the catheter 914, which may facilitate moving the electrosurgical device 912 between the retracted position and the deployed position. The outer sheath 924 may also function to reduce lateral movement of the radiating tip portion 918 within the catheter by acting as a spacer between the radiating tip portion 918 and the catheter 914, which may facilitate movement of the radiating tip portion along the curved distal portion 922 of the catheter 914.

[0109] Figure 10 shows a cross-sectional view of a handpiece 1000 in accordance with an embodiment of the present invention. Figure 11 shows a perspective view of handpiece 1000 with some of the components removed to show the internal structure of handpiece 1000. A further perspective view of handpiece 1000 is shown in Figure 12. Handpiece 1000 can be used with electrosurgical instruments of the present invention, such as electrosurgical instruments 200, 900, 902, to move the electrosurgical device of the instrument along the catheter of the instrument between a retracted position and a deployed position.

[0110] The handpiece 1000 includes a first portion 1002 having a generally cylindrical hollow body 1004. A connector 1006 is provided at the distal end of the hollow body 1004, the connector 1006 being adapted to attach the handpiece to an input port of an instrument channel of a surgical scope device. The connector 1006 may be configured to mate with a corresponding connector on the input port. The connector 1006 may include a luer fitting (or other suitable fitting) to provide a leak-tight connection between the handpiece 1000 and the instrument channel of the surgical scope device.

[0111] The handpiece 1000 further includes a second portion 1008. The second portion 1008 is formed of a generally cylindrical hollow body 1010 that is telescopically mounted within the first portion 1002 such that the second portion 1008 is longitudinally slidable over the length of the first portion 1002. The second portion 1008 includes a set screw 1012 for fixing the position of the second portion 1010 relative to the first portion 1002. The set screw 1012 engages a threaded hole in the side wall of the hollow body 1010. Tightening the set screw 1012 into the threaded hole causes the set screw 1012 to engage the body 1004 of the first portion 1002 and secure the first portion 1002 to the body 1004. The second part 1008 is secured in place relative to the first part 1002. Loosening the locking screw 1012 in the screw hole disengages the locking screw from the first part 1002, allowing the second part 1008 to slide relative to the first part 1002.

[0112] The second portion 1008 includes a holder 1014 disposed inside the body 1010 of the second portion 1008. The holder 1014 is configured to hold the proximal end of a catheter of the electrosurgical instrument. The holder 1014 may be, for example, a clip or clamp disposed 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 can be secured (e.g., using an adhesive). In this manner, when the proximal end of the catheter is held in the holder 1014, the position of the catheter is fixed relative to the second portion 1008. Thus, sliding the second portion 1008 relative to the first portion 1002 moves the catheter relative to the first portion 1002.

[0113] The handpiece 1000 further includes a third portion 1016. The third portion 1016 is formed of a generally cylindrical hollow body 1018 that is telescopically mounted within the second portion 1008 such that the third portion 1016 is longitudinally slidable over the length of the second portion 1008. A coaxial connector 1020 is attached to a proximal end 1019 of the body 1018. A proximal end 1022 of the coaxial connector 1020 is exposed outside the body 1018 of the third portion 1016. The proximal end 1022 of the coaxial connector 1020 is connectable to an electrosurgical generator, for example, via a connecting cable (not shown).

[0114] The distal end 1024 of the coaxial connector 1020 is disposed inside the hollow body 1018 of the third section 1016. The distal end 1024 of the coaxial connector 1020 is disposed to receive the proximal end of a coaxial cable of an electrosurgical device. For example, the distal end 1024 of the coaxial connector 1020 may include an inner conductor and an outer conductor, which may be electrically connected to the center conductor and outer conductor, respectively, of the coaxial cable (e.g., via a soldered or welded connection). Alternatively, the distal end 1024 of the coaxial connector 1020 may be adapted to mate with a corresponding connector on the proximal end of the coaxial cable. The coaxial connector 1020 is configured to transmit electromagnetic energy from a cable connected to its proximal end 1022 to a coaxial cable connected to its distal end 1024.

[0115] A sliding limiter 1026 is attached to the outer surface of the body 1010 of the second part 1008. The sliding limiter 1026 is slidable along the outer surface of the body 1010 of the second part 1008. The position of the sliding limiter 1026 can be fixed relative to the second part 1008 via a set screw 1028 that engages a threaded hole in the sliding limiter. The sliding limiter 1026 includes a stop surface 1030 that is positioned to abut a distal surface 1029 of the body 1018 of the third part 1016 to prevent further distal movement of the third part 1016 when the third part is moved distally (i.e., toward the first part 1002). In this manner, by adjusting the position of the sliding limiter 1026 on the second part 1008, the range of motion of the third part 1016 relative to the second part 1008 can be adjusted.

[0116] 10 and 11, the proximal end of an electrosurgical instrument 1031 is attached to a handpiece 1000. The electrosurgical instrument may be, for example, an electrosurgical instrument according to an embodiment of the present invention, such as those described above. The proximal end of a catheter 1032 of the instrument 1031 is held in a holder 1014 in the second portion 1016 of the handpiece 1000. The proximal end of a coaxial cable 1034 of the instrument 1031 is electrically connected to the distal end 1024 of the coaxial connector 1020 in the third portion 1016 of the handpiece 1000. The coaxial cable 1034 is disposed within the catheter 1032 and extends along the catheter 1032. The electrosurgical instrument 1031 extends through the hollow bodies 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.

[0117] A stiffening tube 1036 is provided around the outer surface of the proximal portion of the coaxial cable 1034. The stiffening tube 1036 is fixed to the coaxial connector 1020. The stiffening tube 1036 is made of a rigid material, such as a rigid metal or a rigid plastic. The stiffening tube 1036 increases the longitudinal stiffness of the proximal portion of the coaxial cable 1034, facilitating the transmission of longitudinal forces to the coaxial cable 1034 when the third portion 1016 is moved relative to the second portion 1008. The proximal portion 1038 of the catheter 1032 has an enlarged diameter to allow the coaxial cable 1034 and the proximal portion of the stiffening tube 1036 to slide within the catheter 1032.

[0118] In use, the distal portion of the electrosurgical instrument 1031 exiting the connector 1006 can be inserted into an instrument channel of a surgical scope device. The connector 1006 of the handpiece 1000 can then be connected to a corresponding connector on an input port of the surgical scope device to secure the handpiece 1000 to the surgical scope device. The length of the catheter 1032 within the instrument channel can then be adjusted by sliding the second portion 1008 relative to the first portion 1002. Because the catheter 1032 is secured to the second portion 1008 (via the holder 1014), moving the second portion 1008 relative to the first portion 1002 changes the length of the catheter 1032 exiting the connector 1006, and therefore the length of the catheter 1032 positioned within the instrument channel. A set of markers 1040 are provided on the exterior surface of the body 1004 of the first portion 1002. Each marker in the set of markers 1040 indicates the length of the catheter exiting the handpiece when the distal face 1041 of the second portion 1008 is aligned with that marker. Thus, the second portion 1008 may be moved along the first portion 1002 to the marker on the first portion 1002 that corresponds to the desired length of the catheter 1032 within the instrument channel. Once the desired length is obtained, the position of the second portion 1008 can be fixed relative to the first portion 1002 by tightening the set screw 1012.

[0119] After adjusting the length of the catheter 1032, the coaxial cable 1034 can be moved along the catheter 1032, for example, to expose or retract the radiating tip portion of the device 1031. The coaxial cable 1034 can be moved along the catheter 1032 by sliding the third portion 1016 relative to the second portion 1008. Longitudinal movement of the third portion 1016 relative to the second portion 1008 is transmitted to the distal end of the coaxial cable 1034, which is connected to the coaxial connector 1020 of the third portion 1016. The stiffening tube 1036 prevents the proximal end of the coaxial cable 1034 from bending, allowing longitudinal movement of the third portion 1016 to be transmitted to the coaxial cable 1034. As the third portion 1016 is moved proximally relative to the second portion 1008, the stiffening tube slides into the expanded proximal portion 1038 of the catheter 1032.

[0120] Because the catheter 1032 is fixed relative to the second portion 1008, sliding the third portion 1016 relative to the second portion 1008 causes the coaxial cable 1034 to slide within the catheter 1032. Thus, when the handpiece 1000 is used with an electrosurgical instrument of the present invention (e.g., the electrosurgical instrument 200), the electrosurgical device can be moved between a retracted position and a deployed position by moving the third portion 1016 rearwardly and forwardly relative to the second portion 1008. Specifically, the electrosurgical device can be deployed by moving the third portion 1016 proximally relative to the second portion 1008. The electrosurgical device can be moved to a deployed position by moving third portion 1016 distally relative to second portion 1008, and can be moved to a retracted position by moving third portion 1016 distally relative to second portion 1008.

[0121] A user may adjust the position of the sliding limiter 1026 on the second section 1008 to set the maximum advancement position of the third section 1016 relative to the second section 1008, thereby setting the maximum extension of the radiating tip section beyond the distal end of the catheter 1032 when the electrosurgical device is in the deployed position. In this manner, the sliding limiter 1026 can prevent the radiating tip section from being pushed too far beyond the distal end of the catheter 1032. The outer surface of the body 1010 of the second section 1008 is provided with a set of markers 1042. Each marker in the set of markers 1042 indicates the maximum extension of the radiating tip section beyond the distal end of the catheter 1032 when the sliding limiter 1026 is aligned with that marker and the distal face 1029 of the third section 1016 abuts the stop face 1030 of the sliding limiter 1026. Thus, sliding limiter 1026 can be moved to a corresponding marker in set of markers 1042 to set the desired maximum extension of the radiating tip portion.

[0122] 13a and 13b illustrate the operation of handpiece 1000 to move the electrosurgical device of instrument 1031 between a retracted position and a deployed position. In Fig. 13a, the electrosurgical device of instrument 1031 is in the retracted position, i.e., the emitting tip portion of the electrosurgical device does not protrude beyond the distal end 1044 of the catheter 1032. In Fig. 13b, the electrosurgical device of instrument 1031 is in the deployed position, i.e., the emitting tip portion 1046 of the electrosurgical device protrudes beyond the distal end 1044 of the catheter 1032. In this configuration, electromagnetic energy can be supplied to emitting tip portion 1046 via coaxial connector 1020 to deliver energy to target tissue.

[0123] To transition from the configuration shown in FIG. 13a to the configuration shown in FIG. 13b, first, the limiter 1026 may be moved to a desired position on the body 1010 of the second portion 1008. Next, the third portion 1016 may be slid distally over the second portion 1008. The third portion 1016 may be advanced until the distal face 1029 of the third portion 1016 abuts the sliding limiter 1026, as shown in FIG. 13b. Once treatment of the target tissue is complete, the third portion 1016 may be slid proximally relative to the second portion, thereby retracting the emitting tip portion 1046 into the catheter 1032 and returning to the configuration shown in FIG. 13a. For purposes of illustration, the length of the device 1031 has been omitted from FIGS. 13a and 13b, as indicated by dashed line 1048.

[0124] Figure 14a shows a cross-sectional view of a catheter 1400 that can be used as part of the electrosurgical instrument of the present invention. The catheter 1400 defines a lumen 1402 extending therethrough within which an electrosurgical device is received. The catheter 1400 includes a proximal portion 1404 having a first diameter 1406 and a distal portion 1408 having a second, smaller diameter 1410. Example dimensions of the first and second diameters are 2.70 mm and 2.30 mm, respectively. A stepped portion 1412 connects the proximal and distal portions 1404 and 1408. The larger diameter of the proximal portion 1404 is positioned such that the proximal portion 1404 can receive a proximal portion of an electrosurgical device coaxial cable that includes a reinforcing element (which increases the effective outer diameter of the proximal portion of the coaxial cable).

[0125] 14b shows a cross-sectional view of another catheter 1414 that may be used as part of the electrosurgical instrument of the present invention. The catheter 1414 defines a lumen 1416 extending therethrough within which an electrosurgical device is received. The catheter 1414 has a proximal portion 1418 having a first diameter 1420 and an intermediate portion 1422 having a second, smaller diameter 1424. The larger diameter of the proximal portion 1404 is arranged so that the proximal portion 1404 can receive the proximal portion of a coaxial cable of an electrosurgical device, including a stiffening element. The proximal portion 1418 and the intermediate portion 1422 are joined by a stepped portion 1426.

[0126] A tapered portion 1428 is disposed at the distal end of the catheter 1414. The tapered portion 1428 serves to reduce the diameter of the catheter 1414 at its distal end from a second diameter 1424 to a third, smaller diameter 1430. The tapered portion 1428 defines a distal opening 1432 of the catheter 1414, the diameter of which is a third diameter 1430. The third diameter 1432 is configured to be larger than the outer diameter of the radiating tip portion of the electrosurgical instrument and smaller than the outer diameter of the instrument's coaxial cable. In this manner, the radiating tip portion can protrude through the distal opening 1432 (e.g., when the electrosurgical device is in the deployed position), but the coaxial cable (which has a larger outer diameter than the radiating tip portion) cannot pass through the distal opening 1432. In this manner, the tapered portion 1428 can function similarly to the plug 222 at the end of the catheter 204. Thus, providing tapered portion 1428 at the distal end of catheter 1414 may eliminate the need for a plug at the distal end of catheter 1414, thereby simplifying the construction of the electrosurgical instrument. Example dimensions for the first diameter, second diameter, and third diameter are 2.70 mm, 2.30 mm, and 1.10 mm, respectively.

[0127] The different sections of catheters 1400 and 1414 may be made by joining together tubes of different diameters. Alternatively, catheters 1400 and 1414 may be made from a single tube formed by a multi-diameter extrusion process. This can be done by extruding the tube at a first diameter and then post-processing a portion of the tube to reshape that portion to a different (e.g., larger) diameter.

Claims

1. 1. A handpiece for controlling movement of an electrosurgical device along a lumen of a catheter, comprising: a first portion having a connector for connecting a distal end of the handpiece to an instrument port of a surgical scope device; a second part connected to the first part and movable longitudinally of the first part, the second part having a holder for holding a proximal end of the catheter, the second part being configured such that relative movement between the second part and the first part controls the length of the catheter extending from the distal end of the handpiece; a third portion connected to the second portion and movable longitudinally of the second portion, the third portion having a coaxial connector configured to receive a proximal end of a coaxial cable carried within the lumen of the catheter, the relative movement between the third portion and the second portion configured to control the relative position of the coaxial cable within the catheter; The handpiece.

2. The handpiece of claim 1 , wherein the second portion includes a locking mechanism for locking the position of the second portion relative to the first portion.

3. the second portion includes a limiter movable in a longitudinal direction of the second portion; The handpiece of claim 1 or claim 2, wherein the limiter is configured to limit movement of the third portion relative to the second portion.

4. the first portion and the second portion are nested together, A handpiece according to any one of the preceding claims, wherein the second part is slidable longitudinally of the first part.

5. the second portion and the third portion are nested together, 10. A handpiece according to any one of the preceding claims, wherein the third portion is slidable longitudinally of the second portion.

6. 1. An electrosurgical system for treating living tissue, the system comprising: an electrosurgical generator configured to supply microwave energy; a surgical scope device having a flexible insertion cord for insertion into a patient's body, the flexible insertion cord having an instrument channel extending longitudinally thereof; and an electrosurgical instrument, the electrosurgical instrument comprising: a flexible catheter having a lumen extending therethrough, said catheter being dimensioned to be insertable through an instrument channel of a surgical scope device; an electrosurgical device disposed within the lumen, the electrosurgical device comprising: a flexible coaxial cable configured to transmit microwave energy; a radiating tip portion connected to a distal end of the coaxial cable to receive the microwave energy, the radiating tip portion having an outer diameter smaller than that of the flexible coaxial cable, the radiating tip portion comprising: a proximal coaxial transmission line for transmitting said microwave energy; a distal needle tip at a distal end of the proximal coaxial transmission line, the distal needle tip configured to radiate the microwave energy into biological tissue; the electrosurgical device is longitudinally movable within the lumen between a deployed position in which the distal needle tip protrudes beyond the distal end of the catheter and a retracted position in which the distal needle tip portion is contained within the catheter; The electrosurgical instrument is sized to fit within the instrument channel, and the system further comprises:

6. The electrosurgical system according to claim 1, 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 the microwave energy.

7. The electrosurgical system of claim 6 , wherein the distal needle tip is configured to operate as a half-wave transformer for delivering the microwave energy from the distal needle tip to living tissue.

8. the catheter includes a constricted passageway at its distal end; 8. The electrosurgical system of claim 6 or claim 7, wherein the constricted passage is sized to allow passage of the radiating tip portion and prohibit passage of the flexible coaxial cable.

9. The electrosurgical system of claim 8 , wherein the constricted passage extends through a plug attached to the distal end of the catheter.

10. The electrosurgical system according to any one of claims 6 to 9, wherein the distal surface of the catheter is rounded.

11. The electrosurgical system of any one of claims 8 to 10, wherein the distal needle tip is retained in the constricted passage when in the retracted position.

12. The electrosurgical system according to any one of claims 6 to 11, wherein the distal needle tip comprises a sharp point at its distal end.

13. The electrosurgical system of claim 12 , wherein the tip is made of a hard insulating material.

14. the distal needle tip comprises a distal dielectric sleeve around a central conductive element; The electrosurgical system of claim 12 or claim 13, wherein the tip is fixed in a lumen at the distal end of the distal dielectric sleeve.

15. The electrosurgical system according to any one of claims 12 to 14, wherein the tip is made of zirconia.

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