Ablation instrument and method of manufacturing same

Abstract

The internally cooled ablation instrument (11) according to the invention comprises a bending section (20) adjoining its distal end (12), in which bending section the ablation instrument (11) bends with respect to its axial direction (A). The amount of angle is preferably defined as one third to two thirds of the maximum measurement angle, preferably as half of the maximum measurement angle. The maximum measurement angle can significantly exceed an absolute value of 140 degrees. Due to the pre-bending in the bending section (20), kink of the hose of the ablation instrument and thus weakening of electrode cooling and the occurrence of high dam pressure can be effectively avoided. When doing so, the ablation instrument (11) according to the invention allows more free work, even more significantly directed to medical aspects and considerations, compared to fully stretched ablation instruments. The treatment safety of a patient is obviously improved.

Description

Technical Field

[0001] The present invention relates to an ablation device, in particular an ablation device for thermally ablating a tissue volume by means of electric current application, and also to a method for producing such an ablation device. Background Art

[0002] EP 3788974 A1 discloses an ablation instrument having a hose-shaped base body, at the distal end of which two ablation electrodes are arranged. The hose is flexible so that the probe can be bent in different directions when inserted into the working channel of an endoscope.

[0003] In addition, US 4,474,174 A discloses a surgical instrument for use in a flexible endoscope. The instrument comprises a catheter in which a surgical tool is arranged. The catheter comprises a defined curvature and an opening in the curvature region, from which a tool guided in the catheter can exit.

[0004] US 6,017,340 A discloses another instrument for endoscopic treatment, in particular endoscopic treatment of the bile duct. The instrument comprises a distal arc-shaped curved end portion traversed by a wire electrode.

[0005] In order to perform operations at difficult-to-access body locations, US Pat. No. 2,022,065 A discloses an instrument having a distal end that is bent backwards to form an acute angle.

[0006] EP 0536440 B1 describes an HF surgical instrument for endoscopic and / or laparoscopic use inside the rectum, wherein the instrument is curved at the distal end. The defined curvature of the instrument facilitates guiding the instrument in the channel of an endoscope, the distal end of the endoscope comprising a rigid curved shape.

[0007] Further prior art is provided by EP 0947171 B1 and EP 1076523 A1.

[0008] For the correct operation of the ablation probe, it is important that the electrodes in contact with the tissue do not get too hot, in order to avoid drying of the tissue in contact with the electrodes. To achieve this, the inner lumen of the hose-like instrument can be used as a cooling channel. However, if the probe is transformed into a curved shape by an endoscope, this cooling channel must additionally be fluid-permeable. Summary of the invention

[0009] The object of the present invention is to provide an ablation device which can be transformed into a curved shape during endoscopic use without restricting its functionality. As a result, particularly large angulations and tight bending radii will be possible. Furthermore, the object of the present invention is to provide a method for producing such an ablation device.

[0010] This object is achieved by means of claims 1 and 15 .

[0011] The ablation device according to the present invention comprises as a base a flexible hose having at least one lumen extending from its proximal end to its distal end. The lumen can be used as a cooling channel to prevent the electrode arranged at the distal end of the hose from being overheated, i.e., to cool the electrode. The electrode can thus be arranged in a section of the hose that does not bend without the application of external forces. In the vicinity of the electrode, the hose comprises a curved section in which the hose is configured to follow an arc without external forces acting on the ablation device. The distal end section of the hose that supports the electrode and is preferably straight, as well as the section that follows the arc direction, and the section adjacent to it in the proximal direction (the latter is also preferably straight) are configured in a flexible manner. Thus, the section that is not curved in the initial state can be curved as required. Conversely, the curved section can be more and more curved or can also be transformed into a straight stretched shape. In doing so, the ablation device can be inserted into or removed from the straight working channel of the endoscope, even if it comprises a curved section. During this process, the curved section is transformed into a non-curved shape.

[0012] The curved segment may have a stiffness that is higher than the stiffness of a segment adjacent to the curved segment of the ablation device in the proximal direction. In addition, the stiffness of the curved segment may be higher than the stiffness of a segment adjacent to the curved segment in the distal direction of the ablation device. However, alternatively, the stiffness of the distal segment of the ablation device may also be higher than the stiffness of the curved segment. In doing so, it may be advantageous to insert the ablation device into rigid tissue (e.g., a solid tumor).

[0013] If the probe is moved with its distal end outside the working channel of the endoscope so that one or more electrodes thereof are inserted into the tissue to be treated, the bending section is preferably arranged in the region of the hose in the bending region of the endoscope. The ablation instrument may also comprise a plurality of bending sections as required.

[0014] The curved section preferably defines a curvature angle of approximately half of the bend provided by the ablation device. For example, if an angulation (i.e., bend) greater than or equal to 145° (e.g., 160°) is desired, the curved section preferably defines an angle of 30° to 70° relative to the longitudinal direction. Other angles are also possible, depending on the needs. On the one hand, the ablation device can be transformed into a stretched shape without damage in order to move through the working channel of the endoscope and into the patient's tissue. On the other hand, the curved section of the ablation device can be bent to an angulation angle of up to 140° to 160° due to a corresponding bend at the distal end of the endoscope, wherein the curvature of the hose in the curved section is increased, however, there is no risk of kinking the hose and thus collapsing its lumen.

[0015] The lumen of the hose is preferably closed at the distal end. Plastics that can be hardened and formed into a plug that closes the end of the hose can be used to close the hose. However, preferably, a closure is inserted into the end of the hose, which closure at least partially consists of an electrically conductive material (e.g., metal). If the closure is provided with a separate electrical connection that can, for example, extend through the lumen of the hose, it can be used as an electrode to simplify the insertion of the instrument into biological tissue and / or to stop bleeding (coagulation). In addition, the closure can be connected to a traction device extending from the distal end of the hose to the proximal end in order to avoid damage to the instrument during retraction from the coagulating tissue.

[0016] The capillary channel may be arranged inside the hose to guide the coolant to the distal end of the ablation device to receive and dissipate the heat originating from the electrode. The capillary channel may be constructed inside the hose itself, for example as a second lumen. Alternatively, the capillary channel may be constructed in a capillary tube that is arranged in the lumen and extends from the proximal end to the distal end. The capillary channel is provided with one or more openings from which the coolant can enter the lumen of the hose near the electrode.

[0017] Preferably, the electrode is designed as a closed hose and in such a way that it has the same effect in all radial directions. For example, the electrode can be designed as a cylindrical electrode or as an electrical conductor wound helically around a hose. The axial orientation of the ablation instrument is therefore irrelevant to the effect on the tissue. If inserted into a stretched straight endoscope that is then bent, the ablation instrument can therefore adopt a rotational position due to the rotation about its axis in which the curvature of the ablation instrument extends in the same direction as the curvature of the endoscope.

[0018] At the distal end of the hose, at least one additional electrode can be arranged on a non-bent section. In this case, the distal end section of the hose, which is located distally with respect to the bent section, supports at least two electrodes, which can be used, for example, for tissue ablation, in particular for tumor ablation, because they are connected to the two poles of the generator. The latter is preferably configured to generate a high-frequency voltage in order to allow a current to flow through the tissue in contact with the two electrodes, thereby causing tissue coagulation. However, it is basically possible to use only one electrode on the ablation instrument, wherein the neutral electrode must be attached to the patient as a counter electrode. However, the configuration with two electrodes has advantages, in particular during use in a high-ohmic environment, for example during the ablation of solid tumors in lung tissue. One or more electrodes can be arranged in whole or in part in the bent section of the instrument.

[0019] In the ablation device according to the invention, the coating is arranged on the hose and forms a gap or a gap-like interspace together with the hose. The coating can extend in particular from the proximal end of the ablation device through the curved section to the electrode or to the insulator adjacent to the electrode. The gap formed between the hose and the coating allows axial relative mobility between the coating and the gap, which supports the flexibility of the ablation device.

[0020] In the curved section, the gap can be filled with plastic, in particular a two-component plastic, so as to provide a rigid connection between the coatings in the hose. The plastic can be used to define the curvature of the ablation device in the curved section. Preferably, the plastic is a flexible plastic so that the curvature can be eliminated or increased due to the application of external forces. Preferably, the plastic is a hardenable plastic, that is, it is inserted into the gap during the manufacture of the ablation device, whereby the curved section is transformed into its curved shape and the plastic is hardened at the same time or subsequently. Thus, the ablation device includes a section with a permanent curvature after the hardening of the plastic. This is the case, although the hose and the coating are indeed flexible, they are straight under unaffected conditions, that is, they are constructed without bending. The plastic filler of the gap produces a hardening of the cross section, so that the lumen is less sensitive to collapse in the area where the plastic filler is provided due to kinking of the ablation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Details of embodiments of the invention and potential additional aspects thereof are derived from the accompanying drawings, the associated description and the claims. In the drawings: Figure 1 A schematic illustration of an ablation instrument inserted into an endoscope and connected to a supply device is shown, Figure 2 The diagram partially shows an ablation device according to the present invention, Figure 3 The enlarged side view shows Figure 2 The distal end of the ablation device, Figure 4 Show according to Figure 3 The distal end of the ablation device, but cut longitudinally, Figure 5 A schematic longitudinal cross-sectional view is shown according to Figures 1 to 4 a portion of a curved section of an ablation device, Figure 6 Show according to Figures 1 to 4 A portion of a curved section of an ablation device is shown, however, in a modified embodiment in a schematic longitudinal section. DETAILED DESCRIPTION

[0022] Figure 11 shows an ablation probe 11 inserted into an endoscope 10, wherein a distal end 12 of the ablation probe 11 protrudes from a working channel of the endoscope 10. However, a proximal end 13 of the ablation probe 11 is connected to a supply device 14 or a device group that supplies the ablation probe 11 with current, voltage and coolant.

[0023] The endoscope 10 comprises a longitudinal straight handle 15 extending in the axial direction A, the distal end 16 of which can be bent more or less by means of an operating element 17 (e.g. an adjusting wheel, an adjusting lever, etc.) arranged on the proximal end of the handle 15. In the vicinity of this operating element 17, depending on the number of working channels present, the endoscope 10 comprises one or more connecting pieces 18, 19, via which probes, instruments, etc. can be inserted into the corresponding working channels of the endoscope 10.

[0024] Preferably, the endoscope 10 is provided for working in tight and angled lumens of the patient's body. For example, it can be used to treat lung tissue, in particular tumors in lung tissue. For this purpose, the distal end 16 of the endoscope 10 can be brought into a straight shape by means of a corresponding actuation of the operating element 17, or also for bending about, for example, up to 140° or more (150°, 160°) relative to the axial direction A. A bending radius of less than 15 mm can thus be produced.

[0025] Figure 2 The ablation probe 11 is illustrated separately based on the distal end 12 of the ablation probe 11 and the segment proximally adjacent thereto. The segment includes a curved segment 20 directly adjacent to the distal end 12, wherein the ablation probe 11 bends without the influence of external forces. In contrast, the distal end 12 and the segment starting at the curved segment 20 and extending up to the proximal end 13 of the probe are preferably straight without the influence of external forces. This straight segment of the ablation probe 11 starting from the curved segment 20 and extending in the proximal direction defines a longitudinal direction, which coincides with the axial direction A of the working channel of the handle 15 if the ablation device 11 is inserted into the working channel. The angle α defined by the curved segment 20 between the distal end 12 and the axial direction A is preferably half of the maximum angulation that must be reached by the distal end 16 of the shaft 15. For example, if a maximum angulation or bending of 150° relative to the axial direction A is to be achieved, the angle α may preferably be between 30° and 70°, preferably about 50° (+ / - 20°). In doing so, the required deformation of the ablation device 11 from the initial shape to the maximum stretched shape or from the initial shape to the maximum bent shape, respectively, is only very small, so that there is no fear of kinking of the ablation probe in the bent position.

[0026] The ablation probe 11 comprises at least one, preferably two electrodes 21, 22 at its distal end 12, which may be rigid or flexible. The electrodes 21, 22 may be configured identically to each other. They have the same electrical activity in each radial direction. In other words, they extend around the entire circumference of the ablation probe 11. As shown in FIG. Figure 3 It is particularly obvious that the electrodes 21 , 22 can be formed by a helically wound electrical conductor. An insulator 23 can be arranged between the electrodes 21 , 22 .

[0027] As in Figure 4 As can be seen in the figure, the two electrodes 21, 22 (preferably also as a sleeve-shaped insulator 23) can be arranged on a hose 24, which extends over the entire length of the ablation device 11 from the proximal end 13 through the electrodes 21, 22 to the instrument tip 25. The instrument tip 25 is formed by an end piece 26, by which a lumen 27 surrounded by the hose 24 is closed. For example, the end piece 26 can consist of metal and can include a cross-shaped end. An insulator element 28 can partially cover the end piece 26 and can extend over the hose 24. The end piece 26 can be connected to the proximal end of the ablation device 11 or to a section of the device that remains outside the endoscope during endoscopic use of the ablation device via a traction device 29, for example in the form of a wire or the like. In addition, a fluid line can be arranged in the lumen 27, which fluid line guides a coolant from the proximal end of the ablation device 11 to the distal end 12 in order to cool the electrodes 21, 22 therewith. The fluid line may include a capillary 30, in particular in the distal region, which may also be used for traction force transmission. The capillary 30 may include one or more coolant outlet openings in the region of the electrodes 21, 22, for example at their distal ends or in their walls, in order to achieve a cooling effect there.

[0028] If Figure 4 and in particular by Figure 5 As shown, the hose 24 is surrounded by a coating 31, which has an inner diameter slightly exceeding the outer diameter of the hose 24, so that a gap 32 is defined between the hose 24 and the coating 31. The coating 31 can thus extend from the proximal end 13 to one of the electrodes 21, 22. Optionally, an insulator ring 33 can be arranged between the distal end of the coating 31 and the electrode 22, adjacent to the electrode 22.

[0029] A special feature of the ablation device 11 according to the invention is a curved section 20 in which the gap 32 is filled with plastic 34. Preferably, however, the plastic filling does not extend along the entire length of the ablation device 11, but is essentially limited to the curved section 20. However, it is also possible to fill a larger area of ​​the gap 32 or the entire gap 32 with plastic 34.

[0030] Instead of the insulator ring 33, a metal or plastic ring 35 can also be provided, which serves in particular as a centering element and from which Figure 6 The ring 35 includes a tubular extension 36 that extends into the gap 32 and centers the coating 31 relative to the hose 24. The plastic 34 that fills the gap 32 in the curved section 20 can extend and seal between the coating 31 and the extension 36.

[0031] The plastic 34 is preferably a curable plastic, for example a two-component plastic, which is inserted into the gap 32, in particular into the curved section 20, in liquid form during the manufacture of the device. In order to form the curved section 20, the curved section 20 is transformed into a curved shape shortly before or shortly after the insertion of the plastic, after which the plastic 34 is cured. For this purpose, the ablation device 11 can be placed in a corresponding holding device, which forces the ablation device 11 in the curved section 20 to assume an arc shape. After the hardening of the plastic, the ablation device 11 can be removed from the curved shape, whereby the region of the ablation device 11 that has been held in the curved shape during the hardening of the plastic 34 forms the curved section 20. However, the remaining section of the ablation device 11 is provided in a stretched form.

[0032] The ablation device 11 described thus far operates as follows: For use on a patient, the endoscope 10 is first inserted into the patient's body, for example into the patient's bronchial system, and placed at the site to be treated. Prior to or at the latest, the ablation instrument 11 is moved via the connection 18 through the working channel of the endoscope 10 to the surgical site. Figure 2 The pre-bent ablation device 11 is elastically transformed into its stretched form and advanced as far as the bent end 16 of the handle 15. As soon as the bent section 20 of the ablation device 11 reaches the bent distal end 16 of the handle 15, due to its tendency to rebound into its pre-bent shape (at least if it accidentally does not have the correct rotational orientation around its axis A), the bent section 20 performs an axial rotational movement. At the same time, with the axial forward movement of the ablation device 11, the ablation device 11 can penetrate or be inserted into the tissue to be treated with its probe tip (i.e. with its end piece 26). For this purpose, where appropriate, the end piece 26 can also be applied with a voltage and a current in order to simplify insertion into denser tissue (e.g. tumor tissue) or in order to coagulate small amounts of bleeding. The current supplied to the end piece 26 can be achieved via the traction device 29 or also via the capillary 30 or a separate conductor.

[0033] Due to the prebend provided by the bending section 20, the distal end 16 of the handle 15 can be bent with a very small bending radius, for example less than 15 mm, but also with a large obtuse angle, for example greater than 145°, relative to the axial direction A, without having to change the kinking of the hose 24 and thus the collapse of the lumen 27. In addition, the hardened adhesive or plastic 34 and the cover 31 have a supporting effect and additionally avoid any kinking tendency of the hose 24. As a result, the coolant supplied via the capillary 30 can flow freely through the lumen 27 back to the device 14 or the outlet arranged near the proximal end 13 without being blocked and thus without reducing the cooling effect on the electrodes 21, 22 or causing a burst in the acute angle state of the ablation device 11. In this way, the device according to the invention also allows the treatment of tumors or other tissue parts that are otherwise difficult to access, which can only be reached by acute angle measurement of the end 16 of the endoscope 10.

[0034] The internally cooled ablation device 11 according to the invention comprises a curved section 20 adjacent to its distal end 12, in which the ablation device 11 is bent relative to its axial direction A. The amount of this angle is preferably limited to one-third to two-thirds of the maximum angulation, preferably half of the maximum angulation. The maximum angulation can significantly exceed an absolute value of 140°. Due to the pre-bend in the curved section 20, kinking of the hose of the ablation device and thus weakening of the electrode cooling and the occurrence of high dam pressures can be effectively avoided. In doing so, the ablation device 11 according to the invention allows freer working, even more significantly oriented to medical aspects and considerations, compared to a fully stretched ablation device. The treatment safety of the patient is significantly improved.

[0035] List of reference numerals: 10. Endoscope 11 Ablation Probe 12 Distal end portion (of ablation probe 11) 13 Proximal end (of ablation probe 11) 14. Device (for operating ablation probe 11) 15 Handle (of endoscope 10) 16 Distal end (of handle 15) 17 Operating element (of endoscope 10) 18, 19 Connecting piece (of endoscope 10) A Axial direction 20 Bending region (of ablation probe 11) α Angle 21,22 Electrodes 23 Insulator 24 Hose 25 Instrument end 26 End pieces 27 Lumen 28 Insulator 29 Traction device 30 Capillary 31 Coating 32 Gap (between coating 31 and hose 24) 33 Insulator 34 Plastic 35 rings 36 Extension.

Claims

1. An ablation device (11), in particular an ablation device (11) for thermally deactivating a tissue volume by means of electric current application, It has a flexible hose (24) comprising at least one lumen (27) extending from a proximal end (13) of the hose (24) to a distal end (12) of the hose (24), It has at least one electrode (21, 22) which is arranged on the distal end (12) of the hose (24), and in, The ablation device (11) includes a curved section (20) in which the hose (24) is configured to follow an arc in the absence of external forces applied to the ablation device (11).

2. The ablation device according to claim 1, characterized in that: The lumen (27) is closed at the end of the distal end (12).

3. The ablation device according to claim 2, characterized in that: In order to close the hose (24), a closing element (26) is provided, which is connected to a traction device (29) extending in the proximal direction from the distal end (12).

4. An ablation device according to any one of the preceding claims, characterized in that A capillary channel is arranged inside the hose (24), and the capillary channel comprises one or more openings near the at least one electrode (21).

5. The ablation device according to claim 4, characterized in that: The capillary channel is formed in a capillary tube (30) extending through the lumen.

6. An ablation device according to any one of the preceding claims, characterized in that The electrode (21) is configured to surround the hose (24), wherein the electrode (21) is formed by an electrical conductor wound helically around the hose (24).

7. An ablation device according to any one of the preceding claims, characterized in that The electrode (22) is arranged outside the curved section (20).

8. An ablation device according to any one of the preceding claims, characterized in that At least one additional electrode (22) is arranged on the hose (24) at its distal end (12) in a non-bent section of the hose (24).

9. The ablation device according to claim 8, characterized in that: The two electrodes (21, 22) are arranged at a distance from each other, however, the two electrodes (21, 22) are configured similarly thereto.

10. An ablation device according to any one of the preceding claims, characterized in that A coating (31) is arranged on the hose (24).

11. The ablation device according to claim 10, characterized in that: A gap (32) is formed between the coating (31) and the hose (24).

12. The ablation device according to claim 11, characterized in that: At least one electrical conductor is arranged inside the gap (32) and extends from the electrode (21) in the proximal direction.

13. The ablation device according to any one of claims 10 or 11, characterized in that: At least in the curved section (20), the gap (32) is filled with plastic (34).

14. The ablation device according to claim 13, characterized in that: The plastic (34) is a flexible plastic.

15. Method for manufacturing an ablation device according to claim 13, characterized in that The plastic (34) is a curable plastic that is inserted into the gap (32), and the ablation instrument (11) is transformed into an arc shape in the curved section, and the plastic (34) is cured.

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