Plasma probe and system

Abstract

The invention relates to a plasma probe and system. The plasma probe (11) is used to generate plasma for medical applications, in particular for the treatment of tissue by coagulation. The probe (11) has a probe body (15) extending from a proximal probe end (13) to a distal probe end (14) and comprises at least one lumen (27) for gas conduction. At the distal probe end (14) at least one electrode (36) and at least one gas outlet opening (35) are provided. The electrode (36) comprises a flow guide (25) at least partially protruding distally from the probe body (15) and is provided with at least one guide surface (32) which is skewed with respect to the longitudinal axis (L). The guide surface (32) is configured to superimpose a lateral flow component on the outgoing gas flow (30) to achieve a targeted shaping and widening of the plasma zone. This improves the ignition stability and effectiveness in lateral applications in particular. The invention also relates to a system (10) comprising the plasma probe (11) and a supply unit (12) with a high-frequency generator (17) and a gas source (20) for plasma generation.

Description

Technical Field

[0001] This invention relates to a plasma probe for generating plasma, particularly useful in medical applications. The plasma can be used, for example, for surface treatment of human tissue, and preferably for the coagulation of human tissue in a patient. Furthermore, this invention relates to a system comprising such a plasma probe and an associated supply unit. Background Technology

[0002] In the medical field, plasma probes used to generate plasma and apply plasma to tissue surfaces are known in different configurations in the prior art.

[0003] EP 1682023 B1 describes a probe for coagulating tissue, configured to feed argon gas into the space between an electrode and the tissue inside the probe. In this probe, the electrode protrudes from the probe at its distal end. At the distal end, a guiding device is further arranged for directing and guiding the gas or plasma, such that at least a portion of the flowing gas or plasma is deflected in a predetermined direction.

[0004] JP 2002-301088 A describes a plasma probe in which a fluid-conducting lumen is guided to a distal electrode. Within the plasma probe, plasma is generated by a combination of fluid flow and high-frequency current. The plasma is then discharged through a nozzle opening at the distal end of the probe.

[0005] WO 2017 / 198869 A1 discloses a plasma system in which two electrodes are helically wound around a dielectric body. Specifically, these electrodes are flat, strip-shaped electrodes resting against the circumferential surface of the dielectric body. An opening is provided in the dielectric body through which a gas for plasma generation can escape into a region between the electrodes where an electric field exists.

[0006] DE 69633182 T2 also discloses a catheter having a flat strip electrode that extends in a spiral manner.

[0007] DE 112022000926 T5 describes an electrosurgical device having a counter electrode and an active electrode having a hydrophobic or superhydrophobic surface. This surface is designed to retain a portion of the gas from a vapor bag when the active electrode is in a conductive liquid solution and has transitioned to a non-active state.

[0008] DE 10030111 A1 discloses a probe for electrosurgical treatment of tissue, comprising a tubular or flexible feeder for delivering inert gas from the surface to a distal end, and electrodes arranged with discharge sections and an electrical feeder for supplying HF current.

[0009] In certain medical applications, such as plasma coagulation in hard-to-reach and convoluted areas (e.g., the stomach), positioning and aligning the plasma probe relative to the patient's tissue remains challenging.

[0010] In particular, in the monopolar operation of plasma probes—meaning the probe has an active electrode and the counter electrode is attached to the patient's body at a distance—a precise distance must be maintained between the probe and the tissue to be treated. Only under these conditions can a high-frequency current (HF current) flow or ignite within the gas flow between the active electrode and the tissue, thereby generating plasma. Too large a distance makes it difficult for the HF current to ignite or flow between the active electrode and the tissue, resulting in no plasma generation and no therapeutic effect. On the other hand, too small a distance increases the risk of accidental contact between the tissue and the active electrode, which could lead to unintended tissue damage. In most known plasma probes, the main gas flow occurs in the axial direction, which makes lateral treatment difficult because relatively less plasma tends to be generated in this region. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide an improved plasma probe that can be used to treat large tissue areas with plasma. In particular, improved ignition behavior of the plasma probe at different distances and at different angles between the plasma probe and the tissue will be achieved.

[0012] This objective is achieved by a plasma probe having the features of claim 1 and the associated system according to claim 15.

[0013] The plasma probe according to the invention has a probe body extending from the proximal probe end toward the distal probe end. The probe body is preferably configured as a flexible hose or flexible tube.

[0014] At least one cavity is formed in the probe body, configured to conduct a gas such as argon. At least one electrode is arranged at the distal probe tip of the plasma probe. Furthermore, at least one gas outlet opening is formed at the distal probe tip. At least one cavity leads to this gas outlet opening, allowing gas flow to exit from the probe.

[0015] In the context of this invention, plasma is understood to be a conductive ionized gas generated, specifically, at atmospheric pressure by applying a high-frequency field. Preferably, the gas used is argon, causing the plasma probe to generate argon plasma.

[0016] Specifically, the at least one electrode has a flow guide that extends along a longitudinal axis and at least partially protrudes distally from the probe body. The flow guide is preferably made of a conductive material. For example, the flow guide can be made of metals such as stainless steel, tungsten, aluminum, copper, silver, etc., or carbon fibers, or other carbon elements such as graphite, graphene, etc. The flow guide may also be provided with a thermally conductive and / or conductive coating, such as silver. At least partially, the flow guide can form at least one electrode. The electrode configured as a flow guide can be used both to shape a gas or plasma flow and to generate the plasma itself.

[0017] The flow guide has at least one guide surface extending along an extension direction. The guide surface is configured to specifically deflect and shape the gas flow. Preferably, the guide surface extends along an extension direction skewed relative to the longitudinal axis. In a particularly preferred embodiment, the extension direction is skewed at each point. The extension direction is defined as the direction in which the (outermost radial) edge of the guide surface continues in a side projection obtained radially relative to the longitudinal axis. Preferably, the extension direction of the guide surface is skewed relative to the longitudinal axis at each point of the guide surface, i.e., the extension direction does not intersect the longitudinal axis. The guide surface extends, in particular, helically around the longitudinal axis of the flow guide. The radial distance between the guide surface and the longitudinal axis can remain at least substantially constant in the distal direction, or can continuously decrease or increase. The extension direction of the guide surface is, in particular (at each location), at an angle to the longitudinal axis of the flow guide. This geometry enables targeted deflection and shaping of the existing gas flow. In particular, the guide surface extends from a section of the flow guide located inside the probe body to a section of the flow guide located outside the probe body.

[0018] Before the gas flow impinges on one or more guide surfaces of the flow guide, the gas flow moves at least substantially axially (i.e., parallel to the longitudinal axis) from proximal to distal. Positioning the electrode as a flow guide allows for the superposition of a lateral component on the gas flow in addition to the axial component, deflecting it outward and thus expanding it. As a result, a spray cone is formed, the diameter of which can vary depending on the (axial) velocity of the gas or plasma flow. At lower velocities, the spray cone diameter is larger than at higher velocities. If a larger treatment area is required, the diameter of an existing gas cone (spray cone) can be increased by reducing the gas flow rate.

[0019] In a preferred embodiment, the flow guide has at least one guiding surface that extends in a helical or screw-like manner and winds around the longitudinal axis of the flow guide. Therefore, the external shape of the flow guide resembles a thread or the cutting edge of a drill bit. With this configuration, the exhaust gas flow is specifically deflected and expanded outwards, thereby forming a spray cone whose diameter can vary depending on the flow velocity.

[0020] A key feature of this invention is the provision of at least one guiding surface by which a lateral flow component, in addition to the axial flow component, is superimposed on the exhaust gas flow. This can be achieved, in particular, by an oblique arrangement of the guiding surface. Due to the oblique arrangement, the gas flow extends laterally, thereby generating a wider plasma formation.

[0021] This is particularly advantageous for handling large tissue areas or lateral applications. Furthermore, the gas flow passes through the (radial outer) edge of the guiding surface where the high-frequency field strength is concentrated. As a result, improved lateral plasma generation can be achieved at the (outer) edge of the guiding surface. In this way, the lateral ignition stability of the plasma can be improved.

[0022] The flow guide preferably has at least one (threaded) flow groove. Specifically, the (threaded) flow groove has at least partially a constant, increasing, and / or decreasing winding radius relative to the longitudinal axis in the distal direction. Preferably, the winding radius of the flow groove decreases from the proximal end of the flow guide toward the distal end. The (multiple) guide surfaces are preferably formed by the sidewalls of the respective flow grooves (on which the (axial) gas flow impinges), i.e., by the sidewalls facing the gas flow. The flow grooves preferably form a corresponding gas outlet opening together with the probe body (i.e., the sheath of the hose or tube).

[0023] The edges of the flow groove (particularly at the transition between the sidewall of the flow groove and the remaining outer surface of the flow guide) are preferably configured as sharp edges or acute-angled edges. These sharp-edge and / or acute-angled edge regions result in a local increase in the electric HF field strength, thereby selectively initiating plasma ignition at these locations.

[0024] After ignition, the plasma discharge is guided and maintained along the corresponding guiding surface, i.e., along the sidewall of the flow groove facing the gas flow. Since the flow guide is also configured as an electrode, the plasma flowing along the sidewall is continuously supplied with a high-frequency current, thereby stabilizing and prolonging the plasma discharge.

[0025] In a preferred embodiment, two, three, or more gas outlet openings are formed at the distal probe tip of the plasma probe. Therefore, in this embodiment, the flow guide has two, three, or more guiding surfaces, each assigned to a corresponding gas outlet opening and arranged such that the gas flow impinges on the corresponding guiding surface. As a result, a more uniform gas distribution can be achieved.

[0026] In cases with multiple gas outlet openings, the flow guide correspondingly has multiple flow grooves, such as two, three, or more, which can be formed in the outer surface of the flow guide. These flow grooves preferably extend helically or in a screw-like manner around the longitudinal axis of the flow guide. In this case, the flow grooves can form multiple gas outlet openings together with the sheath of the probe body.

[0027] The flow guide has a first section disposed inside the probe body and a second section disposed outside the probe body. Multiple guide surfaces or multiple flow grooves may extend along the sub-sections, preferably along most or all of the outer surface of the flow guide. They may extend in the first section, in the second section, or in both sections.

[0028] The cross-sectional shape of the flow groove can be asymmetrical or symmetrical, such as trough, elliptical, circular, or kidney-shaped. The cross-sectional plane extends laterally, that is, at least substantially orthogonal to the extension direction of the guide surface.

[0029] The probe body is preferably configured as a flexible hose. During the fabrication of the plasma probe, a flow guide can be introduced into the hose, and the gas outlet opening is formed by the wall of the probe body and flow grooves. This enables simple and cost-effective fabrication of the distal structure of the plasma probe.

[0030] The guiding surfaces preferably extend helically around the longitudinal axis of the flow guide. When multiple guiding surfaces are provided, they are preferably uniformly distributed and helically extended around a circumferential surface. This results in a uniform lateral widening of the gas jet upon exit.

[0031] The geometry of the flow guide can be substantially cylindrical, truncated conical, or semi-ellipsoidal. This allows for application-specific optimization of flow and plasma parameters.

[0032] The flow guide preferably forms electrodes in at least some regions, such that the electrodes can be used both to broaden the gas flow and to provide high-frequency current in the gas flow for plasma generation.

[0033] In a preferred embodiment, the plasma probe is further configured to dispense jet-forming fluid. For this purpose, the plasma probe may have a jet-forming device for dispensing the jet-forming fluid, the device including at least one jet-forming opening through which the jet-forming fluid can be dispensed at the distal probe tip. This jet-forming device may be a water jet-forming device. This makes it possible to inject the patient's tissue (submucosal injection) with the plasma probe before and / or after plasma treatment, i.e., selectively introducing the jet-forming fluid into or below the tissue layer. As a result, the tissue to be treated may be locally raised or separated from deeper layers. Injections are particularly useful for protecting sensitive structures during intervention, improving the visibility and accessibility of the surgical field, or supporting targeted application of energy, such as plasma or high-frequency treatment. The jet-forming fluid can preferably be dispensed at the distal probe tip in the form of a jet of jet-forming fluid. This jet-forming fluid can be dispensed at pressures up to 80 bar, preferably between 20 and 60 bar. The resulting jet can include velocities in the range of 35 m / s to 72 m / s.

[0034] In one embodiment, the jet forming apparatus may include a central channel formed in a flow guide and configured to conduct jet forming fluid. The channel preferably extends along the longitudinal axis of the flow guide and leads to one or more jet forming openings at the nozzle. For this purpose, the channel connects to a separate lumen of the probe, such that jet forming fluid can be delivered independently of the gas flow from the proximal probe tip to the distal probe tip.

[0035] In a preferred embodiment, the jet forming apparatus has a nozzle element that is at least partially disposed within a through-channel of the flow guide. The through-channel extends along a longitudinal axis from a distal region to a proximal region of the flow guide. The outer diameter of the nozzle element may be smaller than the inner diameter of the through-channel, or may at least substantially correspond to the inner diameter of the through-channel. In particular, the nozzle element may be cylindrical, preferably hollow cylindrical.

[0036] A nozzle channel may be provided in the nozzle element, extending along a longitudinal axis from the proximal end to the distal end of the nozzle element. One or more jet forming openings are arranged at the distal end of the nozzle element. The nozzle channel preferably narrows toward the jet forming openings.

[0037] The nozzle element is preferably fluidly connected to a capillary at its proximal end, allowing the nozzle element to be supplied with a jet of fluid via the capillary. The capillary preferably extends from the proximal probe end to the distal probe end. The capillary is, for example, made of stainless steel.

[0038] Using a dedicated nozzle element can significantly reduce assembly work and simplify the fabrication of plasma probes. The nozzle element can be initially connected to a capillary. For this purpose, for example, the capillary can be widened at its distal end so that the nozzle element can be inserted into the capillary from the distal end. The nozzle element is preferably positioned in the capillary without clearance. Alternatively, the nozzle element may have a widened opening at its proximal end into which the distal end of the capillary can be received, allowing the nozzle element to fit onto the capillary without clearance at the distal end. To achieve a fluid-tight connection between the nozzle element and the capillary, they are connected to each other using a suitable joining technique, such as by creating a circumferential weld by laser welding or a similar method.

[0039] After the nozzle element has been fluidly connected to the capillary, a flow guide can be fitted onto the distal end of the nozzle element, such that the nozzle element and, for example, a sub-section of the capillary are arranged in the through-channel of the flow guide. The flow guide can then be fastened to the capillary in its desired fixed position, for example, by one or more spot welds.

[0040] In a preferred embodiment, the nozzle element may be at least partially arranged in the through channel. The capillary may also be partially arranged in the through channel of the flow guide, such that the connection point between the nozzle element and the capillary is located within the through channel. The jet-forming fluid may be, for example, a NaCl solution, a Ringer's solution, or distilled water.

[0041] In a preferred embodiment, the nozzle element is also configured as an electrode. It is made of a conductive material (particularly a metal such as tungsten or stainless steel). Preferably, the nozzle element is formed as a single piece. In this embodiment, the capillary can also be made of a conductive material (particularly a metal such as stainless steel). Preferably, in this embodiment, the flow guide is in electrical contact with the nozzle element, such that the flow guide can be supplied with a high-frequency voltage via the nozzle element and the capillary. In this way, the nozzle element can perform a combined function of fluid dispensing and as an electrode. Preferably, the nozzle element has higher heat resistance than the capillary and / or the flow guide. Preferably, the nozzle element is made of a material such as tungsten, which is more heat-resistant than the material of the capillary and / or the flow guide. Because the nozzle element is configured as a separate component, it can have higher heat resistance. Thus, the nozzle element remains dimensionally stable even during long processing times. Therefore, in particular, the nozzle opening can maintain its shape even during long processing times. Alternatively or additionally, the nozzle element may also be provided with a coating to increase the heat resistance of the nozzle element. In this embodiment, the coating is made of a material that has higher heat resistance than the material of the nozzle element. For example, the coating may be made of tungsten.

[0042] At the distal end of the flow guide, the nozzle element can be specifically arranged such that it protrudes distally from the through channel, which can improve injection, for example, in terms of achievable precision and maneuverability.

[0043] The plasma probe may also have at least one fixing element disposed proximal to the gas outlet opening inside the probe hose. The fixing element is preferably configured to keep the capillary centered within the probe hose and simultaneously ensure axial fixation between the capillary and the probe hose. For this purpose, the fixing element may include, for example, one or more support plates extending radially between the inner walls of the capillary and the probe hose. The support plates may be welded or crimped to the capillary. Protrusions may be provided on the outer side of the support plates, supporting against the inner wall of the probe hose and thereby reinforcing the connection between the capillary and the probe hose, thus preventing axial displacement of the capillary and nozzle elements and / or flow guides relative to the probe hose. This configuration achieves centeredness and axial fixation of the probe hose to the capillary, ensuring a reliable and long-term stable arrangement.

[0044] The fixing element can be configured as a separate component. Alternatively or additionally, the fixing element can also be directly disposed on the flow guide, for example, through geometric features such as protrusions or barbs (fir tree-shaped) structures on the outer circumference. These features are preferably arranged in a section of the flow guide that is circumferentially closed by the probe tubing in the assembled state. The fixing element prevents the electrode-forming components—i.e., the nozzle element, capillary, and flow guide—from being pulled out of the probe tubing during use.

[0045] The surface of the flow guide preferably has recesses. Preferably, the recesses are configured as multiple grooves or notches. The depth of the recesses is preferably (substantially) less than the depth of the flow grooves. The recesses result in additional edges on the surface of the electrode or flow guide, leading to local field enhancement and thus improving plasma ignition behavior. The recesses can be formed across the entire surface or selectively, particularly in regions outside the probe body. However, preferably, the recesses are formed only on the surface of the flow guide and not in the flow grooves.

[0046] One or more guide surfaces extend in a predetermined angle relative to the longitudinal axis. The angle is particularly between 90° and 0°, preferably between 65° and 15°, and particularly preferably between 65° and 35°.

[0047] Furthermore, in the longitudinal section, the guiding surface may have a tangent arranged at a predetermined angle of attack relative to the radial direction of the flow guide, at least in the central region of the guiding surface. The longitudinal section is a section passing through the flow guide along the longitudinal axis. The guiding surface may be at least partially planar or at least partially curved. In the longitudinal section, the guiding surface may be linear or at least partially curved, for example, convexly curved. The angle of attack may be particularly between 0° and 90°, preferably between 30° and 70°. This arrangement can selectively influence the direction of gas deflection and improve the lateral plasma distribution. Thus, gas forced laterally away from the flow groove can flow through the edge of the flow groove, where the HF electric field strength increases, thereby improving the plasma ignition behavior.

[0048] The object of the present invention is further achieved by a system comprising a supply unit and a plasma probe of the type described above. The features and advantages previously described also apply to the system according to the present invention.

[0049] The supply unit includes an HF generator for supplying HF current to the electrodes and a gas source for supplying plasma gas, preferably an inert gas such as argon. The gas flow rate is preferably adjustable. In the context of this application, the term "HF current" refers to an alternating current having a frequency in the range of about 4 kHz to 500 kHz, preferably between 300 kHz and 500 kHz. The gas is preferably an inert gas such as argon. The flow rate of the gas source supplying the gas flow is preferably variable.

[0050] The plasma probe is connected to the supply unit such that at least one lumen fluid is connected to a gas source, and the gas flow exits from at least one gas outlet opening. If the plasma probe is also configured to dispense jet-forming fluid at the distal probe tip, the supply unit can be additionally configured to supply jet-forming fluid to the plasma probe. The jet-forming fluid is delivered from the proximal probe tip through a capillary to the jet-forming opening at the distal probe tip. Electrodes are electrically connected to an HF generator and can therefore be supplied with HF current.

[0051] The plasma probe is specifically configured for monopolar operation. In this case, an HF generator is configured for monopolar operation, wherein the electrodes of the plasma probe form an active electrode and provide a counter electrode to be attached to the patient's body. The active and counter electrodes are electrically connected to the HF generator. Attached Figure Description

[0052] In the attached diagram: Figure 1 An embodiment of the system according to the present invention is shown; Figures 2 to 6Examples of the distal probe tip of a plasma probe are shown in partial cross-sectional side views, including embodiments having cylindrical, truncated conical, and semi-ellipsoidal flow guides partially arranged inside the probe body, and embodiments having cylindrical flow guides completely arranged outside the probe body. Figures 7 to 9 Different configurations of the flow grooves and corresponding detailed views are shown, including U-shaped, rectangular, and V-shaped cross-sectional shapes; Figure 10 A cross-section through the probe body is shown; Figure 11 , Figure 12 An exemplary configuration of the distal probe tip of a plasma probe is shown in perspective. Figure 13 The flow profile at high flow rates is shown; Figure 14 The flow profile at low flow rates is shown. Figure 15 An example of the assembly of a flow guide at the distal probe tip is shown; Figure 16 An embodiment of the distal probe tip of a plasma probe is shown in longitudinal section; Figure 17 A detailed view of the fixing element is shown in longitudinal section; Figure 18 A detailed view of the fixing element is shown in cross-section.

[0053] Figure label: 10. A system including a supply unit and a plasma solidification probe. 11 Plasma Probe 12 Supply Units 13 Proximal probe tip 14. Distal probe tip 15. Probe Body 16 HF units 17 HF Current Generator 18 pairs of electrodes 19 Feed lines for active electrodes 20 Gas Source 21. Jet Formation Fluid Source 22. The wall of the probe body 23 Electricity feeder 24 channels 25 Flow guide 26. Jet Forming Device 27. Lumen 28 Part One 29 Part Two 30 Gas Flow 31 Flow groove 32 Guiding Surface 33. Extension direction 34 Inclination Angle 35 Gas outlet opening 36 electrodes 37. Depression 38 Relative surface sections 39 Angle of Attack 40 Radial direction 41. Partial Gas Flow 42. Diameter of the exit plasma 43. Central area of ​​the guiding surface 44 Tangents 45 Fixing elements 46 Capillary 47 Support plate 48 Nozzle element 49-point connection 50 jet forming opening 51. Tapered section of the nozzle element 52 Through Passage 53 Stopping surface 54. Protrusion L is the longitudinal axis. Detailed Implementation

[0054] Figure 1 An example of a system 10 according to the invention is shown, which includes a plasma probe 11 and a supply unit 12. The plasma probe 11 extends from a proximal probe end 13 to a distal probe end 14. It has a probe body 15 formed of a flexible tube or hose.

[0055] At the proximal probe tip 13, the plasma probe 11 has multiple connectors through which the plasma probe 11 can be connected to the supply unit 12.

[0056] Supply unit 12 has an HF unit 16 with an HF current generator 17. HF unit 16 has a connector for electrically connecting a counter electrode 18 that can be attached to a body part of the patient. Additionally, a connector is provided for the plasma probe 11, via which a feed line 19 can be connected to an active electrode. Feed line 19 conducts HF current from the proximal probe tip 13 to the distal probe tip 14, where HF current is supplied to the electrode. The illustrated system 10 is configured for unipolar operation, wherein the electrode of the plasma probe 11 serves as the active electrode, and the circuit is closed via the counter electrode 18.

[0057] Furthermore, the supply unit 12 includes a gas source 20 for supplying plasma-generating gas (e.g., argon). The gas source 20 is preferably configured such that the exhaust flow rate is adjustable. The plasma probe 11 is fluidly connected to the gas source 20 via a proximal probe tip 13.

[0058] Optionally, the plasma probe 11 can also be configured to output a jet-forming fluid at the distal probe tip 14. For this purpose, the supply unit 12 can have a jet-forming fluid source 21. The jet-forming fluid source 21 in Figure 1 The dashed line indicates that it is purely optional. The jet-forming fluid source 21 can provide a jet-forming fluid, which can be, for example, a sodium chloride solution, distilled water, or Ringer's solution.

[0059] HF unit 16, gas source 20 and jet forming fluid source 21 can be configured as individual units or as a combination of units.

[0060] Figure 2 An example configuration of the distal probe tip 14 of the plasma probe 11 is shown in a partial cross-sectional side view. In the illustrated example, the probe body 15 of the plasma probe 11 is configured as a flexible tube or tubing with a wall 22. The wall 22 of the plasma probe 11 can be made of a flexible plastic material. Similarly, the wall 22 can have a reinforcing structure; however, this structure... Figures 2 to 6 Not shown in the image. Figures 2 to 6 In the example shown, the electrical feeder 23 is arranged centered relative to the wall 22.

[0061] exist Figures 2 to 6 In the illustrated embodiment, the electrical feed line 23 includes a channel 24 extending from the proximal probe tip 13 to the distal probe tip 14 and leading to a flow guide 25 at the distal probe tip 14. The flow guide 25 continues the channel 24 to a jet forming device 26 disposed distally from which jet forming fluid can be discharged.

[0062] A cavity 27 is formed around the electrical feed line 23, through which gas flow 30 is guided from the proximal probe tip 13 to the distal probe tip 14. Figures 2 to 6 As shown in the diagram, multiple cavities can also be formed around the electrical feed line 23, through which multiple gas streams can be transported from the proximal probe tip to the distal probe tip.

[0063] In this example, the flow guide 25 is cylindrical. It has a first section 28 located inside the probe body 15 and a second section 29 projecting distally from the probe body 15. The flow guide 25 extends along a longitudinal axis L. On the surface of the flow guide 25, there is a flow groove 31 that deflects the gas flow 30 impinging on the flow guide 25. The flow groove 31 has a guide surface 32 extending along an inclined extension direction 33. The inclination relative to the longitudinal axis L is defined by an inclination angle 34.

[0064] The flow groove 31, together with the wall 22 of the probe body 15, forms a gas outlet opening 35 through which the gas flow 30 exits. The outlet direction follows the extension direction 33 of the corresponding guide surface 32. As a result, the gas flow can diffuse laterally according to its velocity.

[0065] The flow guide 25 forms the electrode 36. HF current is supplied to it via the electrical feed line 23. The surface of the flow guide 25 may additionally have multiple recesses 37, for example, in the form of transverse grooves extending transversely to the extension direction 33 of the flow groove 31. The recesses 37 create additional edges, which can lead to local field enhancement and thus improve ignition behavior. The recesses 37 are preferably formed only in the section 29 (exposed section) located outside the probe body 15.

[0066] exist Figures 3 to 6 Another embodiment of the flow guide 25 is shown in the figure. Figure 3 In the middle, the flow guide 25 is a truncated cone shape, and... Figure 4 In this context, the flow guide 25 is semi-ellipsoidal. Figure 3 and Figure 4 In the example shown, the winding radius of the flow groove 31 decreases from its axial height at the gas outlet opening toward the distal end of the flow guide 25. Figure 5 In, such as in Figure 2 In this design, the flow guide is cylindrical but completely positioned outside the probe body 15. Around the opening region where the gas outlet opening 35 is formed, features such as... Figure 5 The sleeve, schematically shown, insulates the electrical feeder from the gas flow. The sleeve is specifically constructed of a non-conductive material such as ceramic. Figure 6 The flow guide 25 is shown as a truncated cone with its diameter increasing in the distal direction.

[0067] Figures 7 to 9 Different cross sections of the flow groove 31 passing through the flow guide 25 are shown in detailed view. Figure 7A U-shaped groove is shown, having a bottom section at the top of the flow groove 31 and opposing sidewalls 38. In this example, the guide surface 32 is concave and curved. In particular, in the central region 43 that does not include either the edge or the top of the flow groove 31, the guide surface 32 has a tangent 44 arranged at an angle of attack 39 relative to the radial direction 40. Figure 8 A rectangular groove is shown. In this example, the guide surface 32 is planar. In the longitudinal section shown, the guide surface 32 extends parallel to the radial direction 40. Therefore, in this example, the angle of attack is at least substantially zero. Figure 9 The example shows a V-shaped groove without a bottom section. In this example, the guide surface 32 is also at least substantially planar.

[0068] Figure 10 A cross-section through the distal probe tip 14 is shown. The wall 22 of the plasma probe 11 is, in particular, a flexible tube wall with a circular (perfectly circular) or elliptical cross-section. The gas outlet openings 35 are asymmetrical and arranged at a distance from the longitudinal axis L. They are formed by the flow guide 25 and the wall 22 of the probe body 15. The flow guide 25 is frictionally held (clamped) against the wall 22 and has a diameter larger than the inner diameter of the wall 22. A channel 24 is also formed in the flow guide 25, which extends along the longitudinal axis L from the proximal end of the flow guide 25 to the distal end of the flow guide 25 and can lead thereto to the jet forming device 26.

[0069] Figure 11 and Figure 12 A perspective view of the flow guide 25 is shown. Figure 11 The image shows a spiral guide surface 32 and a plurality of recesses 37 on the surface. Figure 12 In the middle, the recessed portion 37 is formed by a transverse groove. Furthermore, the channel 24 may also be formed in... Figure 11 and Figure 12 In the flow guide 25 shown, the flow guide 25 leads to the jet forming device 26 at the distal end of the flow guide.

[0070] Figure 13 The flow profile of gas flow 30 at high velocities is shown. Gas flow 30 impinges on the first section 28 of flow guide 25 and is divided into multiple partial gas flows 41, which are guided along a helical path along flow groove 31. The gas flow exits from the probe via gas outlet opening 35. The diameter 42 of the spray cone is relatively small.

[0071] Figure 14 The flow conditions of gas flow 30 at low velocities are shown. The spray cone diameter 42 here is larger than that in... Figure 13 Sun Yat-sen University.

[0072] Figure 15 An example of the assembly of a flow guide 25 at the distal probe tip 14 of a plasma probe 11 is shown. Figure 15 In the example shown, the fixing element 45 is first attached to the capillary tube 46. The fixing element 45 is specifically secured in place on the capillary tube 46. For example, the fixing element 45 can be welded or crimped (press-fitted) to the capillary tube 46. The fixing element 45 may include, for example, one or more support plates 47. The support plates 47 may be rectangular or rhomboid or have a similar shape. Figure 15 In the example shown, the fixing element 45, as an example, has two support plates 47 extending radially relative to the capillary 46. By means of the fixing element 45, the wall 22 of the probe hose 15 is axially fixed to the capillary 46. Furthermore, the capillary 46 is thus centered within the probe hose 15.

[0073] and Figure 15 As shown, the fixing element 45 can also be configured as a separate component. As described above, the fixing element 45 can be additionally or alternatively disposed directly on the flow guide 25, for example, by means of geometric features such as protrusions or barbs (fir tree-like) structures on the outer circumference. These geometric features are arranged in the section of the flow guide that is circumferentially closed by the probe hose in the assembled state.

[0074] At the distal probe tip 14, a capillary 46 protrudes from the probe tubing 15. Figure 15 In the example shown, the capillary 46 has been widened in its distal section, allowing the nozzle element 48 to be inserted distally into the capillary 46. The nozzle element 48 is positioned within the widened section of the capillary 46 without clearance. Furthermore, the nozzle element 48 is secured to the capillary 46 by a circumferential connection 49, such that the jet-forming cavity formed by the capillary 46 is sealed and fluidly connected to the nozzle element 48. Conversely, only a point connection, such as a spot weld, is required between the capillary and the flow guide.

[0075] In the nozzle element 48, a channel 24 formed in the capillary 46 continuously passes through it. At the distal end of the nozzle element 48, a jet forming opening 50 is also arranged through which the jet forming fluid can be discharged. The nozzle element 48 also has a tapered section 51 that leads to the jet forming opening 50 of the nozzle element 48.

[0076] exist Figure 15 The diagram shows a flow guide 25, which is pushed onto the nozzle element 48 from its distal end. For this purpose, the flow guide 25 has... Figure 15 The through channel 52, shown in dashed lines, extends from the proximal end of the flow guide 25 to the distal end of the flow guide 25. Figure 15Unlike other shapes, the flow guide 25 can have another shape, such as Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, it is sufficient as long as it has a through passage 52.

[0077] In the proximal end region of the flow guide 25, a radially extending stop surface 53 is formed on the outer side of the flow guide 25, which serves as a retaining axial stop for the probe hose 15. In the fully assembled state, the end of the probe hose rests against the stop surface 53. The stop surface 53 defines the distance at which the flow guide 25 can be inserted into the distal probe end 14 of the probe hose 15.

[0078] Figure 16 It shows passing through in the assembled state Figure 15 The longitudinal section of an example plasma probe is shown. A stop surface 53 defines the axial length of a first segment 28, which, in the assembled state, is located inside the probe hose 15. The statements above regarding the reference numerals apply accordingly. Figure 16 The longitudinal section shown.

[0079] In the assembled state, the nozzle element 48 protrudes distally beyond the flow guide 25, such that the jet forming opening 50 is arranged spaced apart from the flow guide 25.

[0080] Figure 17 A detailed view of the fixing element 45 is shown. The fixing element 45 has two radially extending support plates 47 fixed in place on the capillary tube 46. At the outer edge of the support plates 47, these support plates 47 additionally have a plurality of protrusions 54, which are configured to improve the mechanical connection between the support plates 47 and the wall 22 of the plasma hose 15.

[0081] Figure 18 A cross-section of the fixing element 45 is shown. (Compared to...) Figure 18Unlike the example shown, the fixing element 45 may also have three, four, five or more support plates 47, each of which extends radially outward from the capillary 46. The support plates 47 may have protrusions 54 at their outer edges, or they may be configured to be smooth. Unlike the example shown, the fixing element 45 illustrated herein may also be configured as a separate component, for example, as a sleeve disposed on and connected to the outer circumference of the capillary. The sleeve may have at least one support plate extending radially outward. Additionally or alternatively, the fixing element 45 may also be disposed directly on the flow guide as described above, for example, by geometric features such as the protrusions 54 shown on the outer circumference of the flow guide 25 or a barbed (fir-like) structure.

[0082] This invention relates to a plasma probe 11 for generating plasma for medical applications, particularly for treating tissues by coagulation. The probe 11 has a probe body 15 extending from a proximal probe end 13 to a distal probe end 14, and includes at least one lumen 27 configured for gas conduction. At the distal probe end 14, at least one electrode 36 and at least one gas outlet opening 35 are provided. The electrode 36 includes a flow guide 25 that at least partially protrudes distally from the probe body 15 and is provided with at least one guiding surface 32 deflected relative to a longitudinal axis L. The guiding surface 32 is configured such that a lateral flow component superimposed on the exiting gas flow 30, thereby enabling targeted shaping and broadening of the plasma region. This particularly improves ignition stability and effectiveness in lateral applications. The invention also relates to a system 10 comprising the plasma probe 11 and a supply unit 12 having a high-frequency generator 17 and a gas source 20 for plasma generation.

Claims

1. A plasma probe (11) having a probe body (15) extending from a proximal probe end (13) toward a distal probe end (14), and having at least one cavity (27) configured for gas conduction, wherein, At the distal probe tip (14) The lumen (27) has at least one gas outlet opening (35), the lumen (27) is connected to the at least one gas outlet opening (35), and a gas flow (30) can be discharged from the at least one gas outlet opening (35). At least one electrode (36) having a flow guide (25) extending along a longitudinal axis (L) and at least partially protruding distally from the probe body (15), The flow guide (25) has at least one guide surface (32) disposed in the gas flow (30), the guide surface extending along an extension direction (33) which is obliquely disposed relative to the longitudinal axis (L) and configured to deflect the gas flow (30) such that the gas flow (30) is discharged with an additional lateral flow component and forms a plasma region widened in the lateral direction.

2. The plasma probe (11) according to claim 1, characterized in that, The plasma region has a variable diameter (42) that depends on the flow rate of the gas flow (30).

3. The plasma probe (11) according to claim 1 or 2, characterized in that, The flow guide (25) has at least one flow groove (31), wherein the guide surface (32) is formed by the sidewall (38) of the flow groove (31) facing the gas flow (30).

4. The plasma probe (11) according to any one of claims 1 to 3, characterized in that, The flow guide (25) has a first section (28) disposed inside the probe body (15) and a second section (29) disposed outside the probe body (15).

5. The plasma probe (11) according to any one of the preceding claims, characterized in that, The probe body (15) is preferably formed as a flexible hose, wherein the first segment (28) of the flow guide (25) together with the wall (22) of the hose forms the at least one gas outlet opening (35).

6. The plasma probe (11) according to any one of the preceding claims, characterized in that, The at least one guide surface (32) extends in a helical path around the longitudinal axis (L) of the flow guide (25).

7. The plasma probe (11) according to any one of the preceding claims, characterized in that, The flow guide (25) is made of a conductive material, wherein the flow guide (25) preferably forms at least a portion of the electrode (36).

8. The plasma probe (11) according to any one of the preceding claims, characterized in that, The plasma probe (11) has a jet forming device (26) for distributing jet forming fluid, the jet forming device (26) including at least one jet forming opening (50) through which jet forming fluid can be distributed at the distal probe tip (14).

9. The plasma probe (11) according to claim 8, characterized in that, The jet forming device (26) has a nozzle element (48) which is at least partially arranged in the through hole (52) of the flow guide (25).

10. The plasma probe (11) according to claim 9, characterized in that, The nozzle element (48) is fluidly connected to a capillary (46) extending from the proximal probe end (13) to the distal probe end (14), in which a channel for jet-forming fluid is formed.

11. The plasma probe (11) according to claim 9 or 10, characterized in that, The nozzle element is made of a conductive material and together with the flow guide (25) forms the electrode (36).

12. The plasma probe (11) according to any one of the preceding claims, characterized in that, Multiple recesses (37) are formed on the surface (25) of the flow guide.

13. The plasma probe (11) according to any one of the preceding claims, characterized in that, The extending direction (33) of the guide surface (32) is arranged at a predetermined tilt angle (34) relative to the longitudinal axis (L).

14. The plasma probe (11) according to any one of the preceding claims, characterized in that, In the longitudinal section, the guide surface (32) has a tangent (44) in at least the central region (43) of the guide surface (32), the tangent (44) being arranged at a predetermined angle of attack (39) relative to the radial direction (40) of the flow guide (25).

15. A system (10) comprising a supply unit (12) and a plasma probe (11) according to any one of the preceding claims, wherein, The supply unit (12) has: - HF generator (17), which is used to supply HF current to the electrode (36), and - A gas source (20) for providing gas for plasma generation, wherein the flow rate is preferably variable. Its features The plasma probe (11) is connected to the supply unit (12) such that the at least one cavity (27) is fluidly connected to the gas source (20), and the gas flow (30) can be discharged from the at least one gas outlet opening (35). The electrode (36) is electrically connected to the HF generator (17) and is configured to be supplied with HF current.

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