Ablation instrument

Abstract

With the concept according to the invention, there is provided a plug (12) for an ablation instrument (11), which is made entirely of plastic, in addition to potential wires (25, 26), and which can be produced in a reasonable manner using an economical manufacturing method, such as using injection molding techniques. In particular, the pin unit (30) contributes to this, on which the pins (31, 32, 33) are arranged and the seat (43) for the fluid line (20) and the connection surface for the gas connection (45) are also made of plastic. In this configuration, the ablation instrument (11) is particularly suited as a disposable instrument, the deposition of which does not require handling or recovery of valuable materials, but requires only reasonably producible plastic portions.

Description

[0001] The present invention relates to an ablation instrument and a therapeutic device comprising such an ablation instrument. The invention thus relates in particular to a CO2-cooled thermal ablation instrument, which inactivates biological living tissue by means of heat or cold. For the heat generation in the tissue, electrodes can be provided on the instrument, which introduce the current into the tissue, but are thereby cooled from the inside in order to keep the electrode-tissue contact moist and conductive. However, the invention can also be used with instruments without electrodes, affecting the tissue by means of cold.

[0002] A cryoprobe is known from CN 1480103 A, which comprises at its distal end an instrument tip which is cooled by means of the Joule-Thomson effect. The instrument comprises an external hose in the lumen of which a fluid line for supplying fluid to the instrument tip is arranged. The hose conveys the fluid supplied to the instrument tip back in the opposite direction. The hose is held in a handle at its (proximal) end which is remote from the patient. A sleeve made of fiber-reinforced plastic is used for this purpose, which is characterized by a low thermal conductivity.

[0003] Furthermore, DE 10 2015 2005 367 A1 uses the thermal insulation properties of fiber-reinforced plastics in so-called cryo-tips.

[0004] An instrument of the type initially mentioned is also known, for example, from EP 2630982 B1. The instrument is equipped at its proximal end with a plug having one or more pins extending in parallel away from the plug housing. They are configured to provide a cooling fluid to the instrument. A cable with an electrical plug for the electrical supply of the instrument extends away from the plug.

[0005] The object of the present invention is to provide an instrument which can be operated with CO 2 and which allows simple production and is thus permanently reliable.

[0006] This object is achieved by an ablation instrument and in particular also by a therapeutic device according to claim 15:

[0007] As mentioned, the ablation instrument according to the invention can be an instrument that affects tissue by means of heat or cold. In both cases, it comprises a hose surrounding an inner cavity, wherein the hose is configured in a closed manner at its distal end and is connected to a plug at its proximal end. The plug is used at least to supply the ablation instrument with liquid, gaseous or also supercritical carbon dioxide (CO2), for which purpose a fluid line originating from the plug extends through the inner cavity of the hose.

[0008] The plug comprises at least one pin connectable to a CO2 source, the pin having an internal channel which can be fluidically connected to a fluid line and which is closed at its outer end located away from the plug. Two annular grooves on the pin arranged at a distance from each other hold seals, in particular annular seals such as O-rings. The seals can be inserted into the annular grooves as separate components or can be connected to the pins in a substance-bond manner. For this purpose, they can be produced together with the pins in a co-extrusion method. Between the two O-rings, a radial opening leading into the channel is formed.

[0009] According to the invention, the pins consist of fiber-reinforced thermoplastics, wherein in particular polycarbonate (PC), polyamide (PA), polybutylene polybutyterephthalate (PBT) or also polyimide (PI) can be considered as plastics. These plastics are preferably reinforced by means of so-called short fibers embedded in the plastic and preferably regularly distributed therein. The fiber percentage can be between 20% and 40% by weight and preferably 30% by weight (wt%). In particular, glass fibers can be considered as fibers, wherein the fiber length is preferably less than 3 mm, further preferably less than 2 mm or also less than 1 mm. Other preferably non-metallic fiber materials that are inert to CO2 and do not absorb CO2 can also be used. In addition, fibers of organic materials can be used, however, preferably fibers from inorganic materials. The thickness of the fibers is preferably between about 5 μm and 10 μm and preferably about 10 μm.

[0010] It has been shown that such fiber-reinforced plastics are also able to withstand long-term effects (longer than 60 minutes) of CO2 at high pressure (more than 50 bar), while the same plastic without fiber reinforcement shows significant strain after a certain duration of effect. Such strain can lead to elongation of the pin and in fact in particular in the area of ​​its (one or more) annular grooves. Due to this elongation, a poor fit of the plug on the corresponding fluid socket may result. This is especially the case if elements such as valves or switches or simple immovable abutment surfaces are provided in the bushing to contact the face of the pin. In addition, in the case of elongation of the pin, it cannot be ruled out that the pin breaks or cracks. The present invention remedies this and allows the use of the plug and the instrument together with the plug throughout several hours of operation. For example, the ablation instrument according to the present invention can be used for tumor ablation, for which it penetrates into the tumor. The electrodes provided on the instrument are used for the supply of current to the tumor and for its cauterization by means of heat buildup. In order to maintain the electrical contact between the tumor tissue and the electrode necessary for this purpose, the electrode is cooled from the inside. For this purpose, carbon dioxide is served which is conveyed under high pressure through a plug which now receives carbon dioxide despite the configuration of its plastic pins.

[0011] An electrical connection means may be provided on the plug for the supply of current to electrodes optionally provided on the ablation instrument. For example, such a connection means may be formed by one or more contacts, which may be provided on one or more pins of the plug. In a preferred embodiment, the connection means is formed by an electric wire with an electric plug. The wire may be a cable extending from a plug establishing a fluid connection with the instrument to another plug with an electrical contact pin, which may be plugged into a generator provided for this purpose.

[0012] Preferably, the plug comprises a plug housing in which the plug unit is arranged. The plug unit is preferably configured as a monolithic injection molded part, which comprises a head arranged in the plug housing and at least one or more pins extending from the head in parallel to each other. If only one pin is present, it can be configured in a stepped manner so as to connect multiple fluid channels. The pin unit is formed integrally with the pin without gaps with the same fiber-reinforced thermoplastic. It unites all necessary functional elements with a gas junction so as to connect the hose and the fluid line in a fluid-tight manner and to guide potentially existing wires out of the inner cavity of the hose in a gas-tight manner. In addition, it redirects the coaxial gas delivery of the instrument to the parallel gas delivery of the pins of the plug.

[0013] The material selection according to the invention allows to provide a particularly small wall thickness, in particular in the region of the slot of the respective pin. This wall thickness can be less than the width of the respective slot measured in the longitudinal direction of the pin. On the other hand, it is facilitated to define a channel diameter in the region of the slot that is greater than the wall thickness. This avoids undesirable throttling effects in the gas path during the gas supply to the instrument and thus has a good cooling effect at its distal end.

[0014] Additional details of advantageous embodiments of the invention are the subject of the figures, drawings and the corresponding description or claims. The drawings show:

[0015] Figure 1 The invention is a treatment device having an ablation instrument, the plug of which is connected to a socket of a supply device, the supply device being connected to a CO2 gas source,

[0016] Figure 2 is based on a single perspective Figure 1 The ablation instrument plug, and

[0017] Figure 3 The longitudinal section view and the partial enlargement view are based on Figure 1 and Figure 2 the pins of the plug.

[0018] exist Figure 1 In FIG. 1 , a treatment device 10 is illustrated, which comprises an ablation instrument 11 having a plug 12 provided at its proximal end. Also part of the treatment device is a gas supply unit 13 which delivers carbon dioxide gas (CO 2 ) from a storage device 14 to a gas socket 15 .

[0019] The ablation instrument is preferably configured as a single-use instrument, which is not provided for multiple use for different patients and is therefore not intended for reconditioning. However, in principle, it can also be designed as a reusable instrument.

[0020] The ablation device 11 comprises a flexible hose 16 which can be introduced into the patient via a working channel of an endoscope, for example, wherein the proximal end 17 of the hose 16 terminates in the plug 12 and is held in a gas-tight manner. The hose surrounds an inner cavity 18 extending from the proximal end 17 to a distal end 19, at which the hose 16 and therefore the inner cavity 18 are closed.

[0021] Inside the lumen 18 is arranged a fluid line 20 for supplying CO2 to a distal section 21 of the instrument 11 and to the hose 16. The proximal end 22 of the fluid line 20 is in turn held in a fluid-tight manner in the plug 12. The fluid line 20 may comprise one or more outlet openings at its end in order to allow the CO2 to escape therefrom, thereby expanding and thereby absorbing heat, which means that it cools.

[0022] In the distal section 21, one or more electrodes 23, 24 may be arranged for supplying current and thus heating biological tissue. They may be connected via corresponding wires 25, 26 to a plug 27, with which they form an electrical connection member 28. The plug 27 may include one, two or more electrical contact pins 29 for supplying current to the electrodes 23, 24 via the wires 25, 26. In addition, one or more contact pins 29 may be configured and used for instrument identification.

[0023] The plug 12 of the instrument 11 according to the present invention comprises a pin unit 30 having at least one pin, but preferably a plurality of pins 31, 32, 33, which extend parallel to each other away from a headpiece 34 and are seamlessly integrally configured with the headpiece 34.

[0024] about Figure 1 and Figure 3 The following description of the pin 32 of the gas socket 15 applies accordingly to the other pins 31, 33. The pin 32 comprises a longitudinal tubular base body, on the outside of which two annular grooves 35, 36 are arranged at an axial distance from each other. The annular grooves 35, 36 are used to position sealing elements therein, such as O-rings 37, 38, with which the pin 32 is positioned in a sealing manner in a corresponding jack 39 of the gas socket 15. The pin 32 surrounds a channel 40, which is closed at an end 41 located away from the plug 12. If the plug 12 is inserted into the gas socket 15, a radial opening 42 connects the channel 40 with the interior of the jack 39. The jack 39 is connected to the gas supply unit 13 via a fluid channel 39a and is supplied with pressurized (for example between 40 and 70 bar) CO2 via the latter.

[0025] The pin 32 has a wall thickness w1 at the annular groove 36 around the channel 40 which is smaller than the wall thickness w2 measured therefrom between the annular grooves 35, 36. Furthermore, the wall thickness w1 is preferably smaller than the groove width b and also smaller than the channel diameter d.

[0026] The channel 40 opens out in a passage of the head piece 34 which also forms a seat 43 for holding in a sealed manner the proximal end 22 of the fluid line 20. The fluid line 20 is held there in a sealed manner against the seat 43 by means of a seal. At the proximal end 22 of the fluid line 20, a holding piece 44 is fixed by means of an adhesive.

[0027] Furthermore, a gas connection 45 is held on the head part 34, which is arranged in a gas-tight manner on the side facing away from the pins 31 to 33, for example on a flat surface of the head part 34, forming a mounting area 50. This mounting area 50 forms a seat for the gas connection point. The gas connection point serves to guide the lines 25, 26 out of the inner cavity 18, redirect the expanded CO2 back to the pins, and at the same time fix the holder 44 inside the seat 43. The holder 44 and the gas connection point 45 can thus be configured integrally. The hose 17 is fixed in the opening of the gas connection point 45 by means of an adhesive 46. The gas connection point 45 comprises a channel, via which the inner cavity 18 is connected to the channel 40' of the pin 33. Furthermore, the gas connection point 45 comprises a seal or a sealing adhesive joint for the lines 25, 26, for contacting the electrodes 23, 24 in order to guide them out of the gas delivery area of ​​the plug 12.

[0028] As in Figure 2 As indicated in FIG. 1 , the plug 12 comprises a plug housing 47 which may be formed by two housing shelves 48, 49, for example made of plastic. The head piece 34 and the gas connection point 45 are mounted in the plug housing 47. The pins 31, 32, 33 project out of the housing 47.

[0029] When using the ablation instrument 11, the treatment device 10 described so far operates as follows:

[0030] For the deactivation of biological tissue, the ablation instrument 11 penetrates with its distal section 21 into the tissue to be deactivated, for example a dense lung tumor, so that both electrodes 23, 24 are located inside the tumor. When the instrument 11 is activated, the gas supply unit 13 delivers carbon dioxide taken from the storage device 14 to the gas socket 15 at a controlled pressure in the range of 40 bar to 70 bar, and there in particular to the central plug hole 39. The corresponding gas delivery channel 39a thus ends inside the plug hole between the two O-rings 37, 38 of the pin 32 inserted into the plug hole 39.

[0031] Through the radial openings 42 and the channel 40, the carbon dioxide now flows to the seat 43 and from there through the fluid line 20 up to the distal section 21 of the instrument in order to cool it and with it the electrodes 23, 24. From there, the CO2 flows out of the fluid line 20 into the lumen 18 and expands therefrom with considerable cold development.

[0032] At the same time, the electrodes 23, 24 are supplied with electric current via the plug 27 or another connecting member 28, the electric current flows through and thus heats the tumor. The cooling of the electrodes 23, 24 thus avoids overheating, so that the maximum local temperature is not provided on the electrodes 23, 24 but at a certain distance from the electrodes 23, 24. This treatment process may require a significant time period of, for example, 15 minutes. In addition, the therapist can combine a plurality of such treatments with each other, because he treats the corresponding tumor several times or treats (ablates) additional tumors accordingly. This means that, for a significant total duration that can significantly exceed one hour, carbon dioxide flows through the channel 40 of the pin 32 at a pressure of approximately 40 bar to 50 bar or more. As a result, carbon dioxide diffuses into the plastic of the pin 32, which can reduce the tensile strength of the plastic. However, due to the presence of fibers, in particular glass fibers, in the plastic, the softening of the plastic and, in particular, the expansion in the region of the annular groove 36 are effectively suppressed. As a result, the pin 32 maintains its length; it neither expands in the pin longitudinal direction (direction of the channel 40 ) nor does it risk breaking in the regions of its small wall thickness (eg in the region of the annular groove 36 ).

[0033] With the concept according to the invention, a plug 12 for an ablation instrument 11 is provided which, apart from the potentially provided electrical wires 25, 26, is made entirely of plastic and can be produced in a reasonable manner by an economical manufacturing method, for example by injection molding technology. In particular, the pin unit 30 contributes to this, on which the pins 31, 32, 33 are formed as well as the seat 43 for the fluid line 20 and the connection surface for the gas connection point 45, which also consists of plastic. In this configuration, the ablation instrument 11 is particularly suitable as a disposable instrument, the deposition of which does not require the disposal or recycling of valuable materials, but only requires a reasonably producible plastic part.

[0034] Reference Symbols:

[0035] 10 Treatment Equipment

[0036] 11 Ablation Instrument

[0037] 12 Plug

[0038] 13 Gas supply unit

[0039] 14 Storage Devices

[0040] 15 Gas socket

[0041] 16 Hose

[0042] 17 Proximal end of hose 16

[0043] 18 Lumen

[0044] 19 Distal end of hose 16

[0045] 20 Fluid lines

[0046] 21 Distal section of hose 16

[0047] 22 Near end of fluid line

[0048] 23, 24 Electrodes

[0049] 25, 26 Wire

[0050] 27 Plug

[0051] 28 Electrical connection components

[0052] 29 electrical contact pins

[0053] 30-pin unit

[0054] 31…33 pins

[0055] 34 Head parts

[0056] 35, 36 Annular groove

[0057] 37, 38 O ring

[0058] 39 Gas socket 15 socket

[0059] 39a Fluid channel

[0060] 40 channels

[0061] 41 End of pin 32

[0062] 42 Radial opening

[0063] w1 Wall thickness at the annular groove 36

[0064] w2 Wall thickness between annular grooves 35 and 36

[0065] b Slot width

[0066] d Channel diameter of channel 40

[0067] 43 seats

[0068] 44 Retaining parts

[0069] 45 Gas Area

[0070] 46 Adhesive

[0071] 47 Housing

[0072] 48, 49 Shell

[0073] 50 Installation area of ​​gas junction 45

Claims

1. An ablation instrument (11): A hose (16) having an inner cavity (18), wherein the hose (16) comprises a distal section (21) and a proximal end (17), and is configured in a closed manner at its distal end (19) and is connected to a plug (12) at its proximal end, having a fluid line (20) extending from the plug (12) through the lumen (18) to the distal section (21), in, The plug (12) includes at least one pin (32) which can be connected to a CO2 gas supply unit (13) and has an internal passage (40) connected to a fluid line (20), The pin (32) comprises two annular grooves (35, 36) arranged at a distance from each other, with sealing rings (37, 38) arranged therein, and a radial opening (42) leading to the channel (40) is formed between the sealing rings (37, 38), It is characterized in that the pin (32) consists of fiber-reinforced thermoplastic.

2. The ablation instrument according to claim 1, characterized in that: At least one electrode (23, 24) is arranged on the hose (16) at its distal end section (21), wherein the at least one electrode (23, 24) is connected to an electrical connection member (28) provided on the plug (12).

3. The ablation instrument according to claim 1 or 2, characterized in that: The plug (12) comprises a plug housing (47) in which a pin unit (30) is arranged.

4. An ablation apparatus according to any one of the preceding claims, characterized in that A plurality of stitches (31, 32, 33) are arranged on a stitch unit (30) extending parallel to each other and are seamlessly integrally made of the same fiber-reinforced thermoplastic.

5. An ablation apparatus according to any one of the preceding claims, characterized in that The channel (40) arranged inside the pin (32) is closed at its free end (41).

6. An ablation apparatus according to any one of the preceding claims, characterized in that The pin (32) has a wall thickness (w1) in the region of the slot (36) that is smaller than a wall thickness (w2) outside the slot (36).

7. An ablation apparatus according to any one of the preceding claims, characterized in that The pin (32) has a wall thickness (w1) in the region of the groove (36) that is less than half the wall thickness (w2) outside the groove (37).

8. An ablation apparatus according to any one of the preceding claims, characterized in that The pin (32) has a wall thickness (w1) in the region of the groove (36) which is smaller than a width (b) of the groove (36) measured in the longitudinal direction of the pin.

9. The ablation apparatus according to any one of claims 3 to 8, characterized in that: The pin unit (30) comprises a seat (43) for mounting the fluid line (20) in a sealed manner.

10. The ablation apparatus according to any one of claims 3 to 9, characterized in that: The pin unit (30) comprises a mounting area (50) for mounting a gas junction element (45), the gas junction element (45) comprising a seat for mounting the proximal end (17) of the hose (16) in a sealing manner.

11. An ablation apparatus according to any one of the preceding claims, characterized in that The plastic is PA, PC or PBT.

12. An ablation apparatus according to any one of the preceding claims, characterized in that The plastic comprises a fibre percentage of 20% by weight to 40% by weight, preferably 30% by weight.

13. An ablation apparatus according to any one of the preceding claims, characterized in that The fibers present in plastics are glass fibers.

14. An ablation apparatus according to any one of the preceding claims, characterized in that The fibers present in the plastic have a length of less than 3 mm, preferably less than 2 mm and further preferably less than 1 mm.

15. A therapeutic instrument (10), comprising an ablation instrument (11) according to any one of the preceding claims, a gas storage device (14) and a CO2 gas supply unit (13), the CO2 gas supply unit (13) having a socket (15) suitable for a plug (12) of the ablation instrument (11), wherein the socket is connected to the CO2 gas supply unit (13) via a fluid channel.

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