Cryoprobe

Abstract

The inventive cryoprobe comprises a head (20) to which a cryogenic fluid is supplied via a capillary (22a). A hose (18) is used for the removal of the cryogenic fluid, wherein the capillary (22a) extends through its lumen (21). The capillary (22a) comprises a flexible section (25) bridged by a pulling element (26). In this way, a well-manipulatable cryoprobe 11 is obtained, which can be bent easily and to a very large extent and still transmits the tension necessary for sample extraction.

Description

Technical Field

[0001] The present invention relates to a cryoprobe which is particularly suitable for tissue probing in highly branched vascular systems, such as for example for obtaining tissue samples in the upper urinary tract, in particular in the renal calyceal system. Background Art

[0002] Cryoprobes for tissue biopsy are known in principle. For example, DE 10 2011 000 004 B4 discloses a flexible cryoprobe with a hose comprising a cavity and a metal head in the form of a cup arranged at its distal end, the diameter of which corresponds to the diameter of the hose and which comprises a round bottom at its distal end. A capillary is arranged in the hose, which extends over the entire length of the hose and terminates inside the head. The capillary is used to introduce a cryogenic fluid into the head for cooling the head.

[0003] Similar cryoprobes are known from EP 2 257 235 B1, EP 2 170 197 and EP 2 114 276 B1.

[0004] During tissue sampling, the distal end of the probe is cooled until the tissue to be sampled is frozen to the head of the probe. The tissue is then separated from the non-frozen tissue, i.e., torn off and guided with the probe out of the patient's cavity. In a branched cavity, it also depends on being able to bend the probe with a small bending radius, where bends significantly greater than 90° may be expected. Summary of the invention

[0005] Based on this, the object of the present invention is to provide a cryoprobe suitable for such demanding applications.

[0006] This object is solved by the cryoprobe according to the invention.

[0007] The cryoprobe of the present invention comprises a flexible tube, which is provided at its end with a head for tissue sampling. A capillary extends through the lumen of the flexible tube to supply the head with a cryogenic fluid. The capillary is a conductor whose pressure resistance matches the cryogenic fluid used.

[0008] In addition, a traction line is arranged in the lumen of the hose, which serves to transmit tension between the proximal end and the head of the cryoprobe. This allows the use of highly flexible capillaries in one or more sections or as a whole, and on the other hand also allows the necessary traction to be transmitted from the proximal end on the head in order to pull the tissue frozen to the head away from the non-frozen tissue and thus perform tissue detection.

[0009] The cryoprobe of the present invention is flexible so that it can be bent at large angles with the application of small forces and it combines this with a high tensile strength.

[0010] The cryoprobe can be constructed in a filamentary manner and can have an outer diameter of less than 1.2 mm, so that it can also be used in very narrow endoscopes. Bending angles (i.e., bending) greater than 150° (preferably greater than 160°) can be achieved with the inventive concept. In doing so, due to the high flexibility of the cryoprobe, the bending can be performed with a small force, which has to be applied by the endoscope.

[0011] Preferably, the capillary is made of a material in which an increase or decrease in its tensile strength can be achieved by an influence (e.g., heat treatment). It is also preferred that the capillary is treated or processed so that it includes at least one section in which the material tensile strength and therefore also the bending resistance of the capillary are reduced compared to the tensile strength and therefore also the bending resistance of the remaining capillaries. This section with reduced tensile strength and reduced bending resistance is preferably arranged in the distal section, which is bent by the endoscope in use. The capillary is composed of, for example, steel or another material with tensile strength and resistance to bending. For example, in a section in which the probe is bent with a small bending radius, the steel can be soft annealed. Alternatively, the section may be formed by a capillary piece of another material (e.g., plastic, copper, etc.).

[0012] The pull line is used to transfer tension from the proximal end of the probe to the head. It is arranged to at least cross the soft section of the capillary. For this purpose, the pull line is connected to the head of the instrument in a tension-resistant manner at the distal end. For this purpose, the pull line can be attached directly to the head, or it can also be attached to the tension-resistant section of the capillary, which in turn is connected to the head.

[0013] The distal end of the pull line can lead to the distal end of the probe or (as preferred) can be connected to the tensile strength distal section of the capillary. Therefore, the pull line at least crosses the capillary section with reduced bending resistance.

[0014] The pull wire can be connected to the capillary in a tensile manner, for example via a solder joint, a weld or other type of connection. Preferably, the pull wire is placed parallel to the capillary, i.e., the connection positions between the pull wire and the capillary are arranged in the same angular position with reference to the capillary cross section. Doing so allows free angular movement of the probe in all radial directions.

[0015] Although it is basically possible to bridge the angularly flexible section of the capillary with a plurality of pull wires, it is preferred to provide only one pull wire. In doing so, the cryoprobe achieves good movability in all directions.

[0016] The diameter of the pull wire is preferably less than the difference between the diameter of the cavity and the outer diameter of the capillary. In doing so, the capillary and the pull wire remain movable in radial and circumferential directions inside the cavity. During the bending of the probe in which the pull wire is positioned radially outward relative to the bending radius, at least the central section of the pull wire can move in the cavity and can reach the opposite side of the cavity. In doing so, in this case, the pull wire also does not provide resistance to bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further details of advantageous embodiments of the invention emerge from the figures and the description. The figures show:

[0018] Figure 1 , which shows in a schematic perspective view an endoscope with an inventive probe,

[0019] Figure 2 , which shows the distal end of the endoscope with the probe in a bent condition,

[0020] Figure 3 , which shows the distal end of the probe in a schematic longitudinal cross-section,

[0021] Figure 4 , which shows a portion of the distal end of the probe in a schematic longitudinal cross-sectional view,

[0022] Figure 5 and Figure 6 , which respectively show the interception along line VV or VI-VI according to Figure 4 A cross-sectional view of the probe,

[0023] Figure 7 , which shows an alternative embodiment of the apparatus,

[0024] Figure 8 , which is shown in cross section according to Figure 7 equipment. DETAILED DESCRIPTION

[0025] Figure 1 An endoscope 10 is shown, into which a cryoprobe 11 is inserted. It extends from a proximal end 12 of the endoscope to a distal end 14, which can be moved by means of an operating element 13. The endoscope 10 comprises a longitudinal shaft 15, through whose passage the cryoprobe 11 is guided. The distal end 16 of the cryoprobe 11 can be retracted into the shaft 15 or moved outside the shaft 15. The outer diameter of the cryoprobe 11 is preferably slightly smaller than the inner diameter of the passage provided in the shaft 15.

[0026] The operating element 13 is used to control the distal end 14 of the shaft 15, in particular to move it relative to the axial direction 17 (such as Figure 2 The angle α achievable thereby is preferably greater than 90°, and also preferably greater than 140°, and in the preferred case greater than 160°. In the case of an outer diameter of the shaft 15 of less than 3.3 mm, the bending radius is thus less than 20 mm, preferably less than 15 mm.

[0027] Figure 3In the figure, the cryoprobe 11 is shown alone in the region of its distal end 16. It comprises a hose 18, to which a head 20 is attached in a fluid-tight manner at the distal end 19 of the hose 18. The hose 18 surrounds a cavity 21 and is at least highly flexible in a section adjacent to the head 20. Figure 3 Schematically shown in FIG is a head 20. It preferably comprises an outer diameter corresponding to the outer diameter of the hose 18. At its distal end, the head 20 is closed by a flat, curved or otherwise configured bottom.

[0028] In addition, the hose is provided with a fluid channel 22, which serves to guide the cooling fluid to or in the head 20. The fluid channel 22 can be formed by a capillary tube 22a, which extends through the cavity 21 of the hose 18. The capillary tube 22a can be connected to the head 20 at its head-side end 23. The connection can be established by a connecting element (not shown in detail) or (e.g. from Figure 3 Obviously) is established directly by weld seams 24, weld points, etc.

[0029] The capillary 22a may be open at its distal end or may be provided with a nozzle. The nozzle may also be formed on the capillary. Preferably, the capillary 22a is composed of tensile steel (e.g. X2CrNiMo 1.4404 or X2CrNiMo 1.4401). Preferably, the material of the capillary 22a has a tensile strength greater than 900 N / mm 2 The capillary tube 22a is used to allow cryogenic fluid to be inserted into the internal space of the head 20 for cooling the head 20 and for transmitting tension during biopsy sampling.

[0030] However, the capillary 22a is not continuously constructed in a tensile manner. Figure 4 In its section 25 shown separately in FIG. 2 , the capillary 22a is reduced in its tensile strength and thus also in its bending resistance by heat treatment (eg by softening). Preferably, the tensile strength in this section is less than 700 N / mm 2 In this way, the capillary tube 22a can also resist the pressure load caused by the cryogenic fluid in the section 25. Figure 2 As indicated in , it is flexible so that the cryoprobe can be bent with a small bending radius. However, section 25 does not have sufficient tensile strength to transmit the tensile force necessary for biopsy sampling.

[0031] The section 25 is bridged by a traction element 26, which in the present embodiment is a traction wire 27. It consists of a tensile material which transmits the tensile force necessary for the biopsy sampling within its elastic stress in relation to the capillary 22a. The traction wire 27 is connected to the capillary 22a at its two ends by welded connections 28, 29 (e.g. welds), which also transmit tensile force within its elastic stress. However, the traction element 26 largely keeps the traction stress away from the softened position of the capillary 22a. However, measured along the length of the capillary 22a, the distance between the welds 28, 29 is greater than the length of the section whose tensile strength and bending resistance are reduced compared to the rest of the capillary 22a.

[0032] This is Figure 5 and Figure 6 It is shown in Figure 5 and Figure 6 It is also made apparent that the welded connections 28, 29 at both ends of the pull wire 27 are arranged at the same radial position of the capillary 22a. Figure 3 As indicated in FIG, between the two welded connections 28, 29, the pull wire 27 is in non-tensioned (relaxed) and laterally movable contact with the capillary 22a, or extends at a short distance from the capillary 22a. In this orientation, the pull wire 27 is oriented largely parallel to the capillary 22a.

[0033] For biopsy sampling, the cryoprobe 11 is inserted into the patient's cavity with the endoscope 10, with the distal end 16 in contact with or penetrating the patient's tissue to be sampled. Inserting the cryoprobe 11 into the endoscope 10 is particularly simplified, wherein the cryoprobe 11 is rigid along almost its entire length - corresponding to the rigidity of the capillary 22a, i.e., more rigid than the section 25. However, the instrument as a whole is flexible. The length portion limited only by the section 25 is less resistant to bending and is more easily bent.

[0034] like Figure 2 As shown in FIG. 1 , if necessary, the endoscope can be bent at an angle of more than 160°. In doing so, the endoscope 10 and the cryoprobe 11 can be inserted into a narrow and highly branched blood vessel of a patient. Thus, the cryoprobe 11 is dimensioned so that the section 25 is located in the region of the bent position of the endoscope. Thus, if the head 20 is still positioned at the opening of the distal end 14 of the shaft 15, and if the head 20 (e.g. Figure 1 and Figure 2The section 25 is preferably long enough to allow bending to be possible, as shown in FIG. 2 . The section 25 is preferably long enough to allow bending to be possible, as shown in FIG. 2 . Preferably, the length of the section 25 has an amount greater than a few centimeters, preferably greater than 10 cm. The bending of the endoscope 10 is only slightly impeded by the rigidity of the capillary 22 a, since the section 25 is constructed in a correspondingly flexible manner. The hose 18 is also made of a flexible material, preferably plastic, preferably PEEK or PA, which only slightly impedes the bending of the endoscope. The tension-resistant traction wire 27 also does not offer any significant resistance to bending due to its small diameter. The diameter of the traction element 26, in particular the traction wire 27, is smaller than the diameter of the capillary 22 a.

[0035] For sampling, the head 20 is supplied at the inside with a cryogenic fluid, which is inserted into the head 20 via the capillary 22a. Due to the cooling of the head 20, the part of the tissue to be sampled is frozen to the head 20.

[0036] For sampling, the cryoprobe 11 is moved in the proximal direction. In doing so, the tissue frozen to the head 20 is pulled away from the remaining tissue. The force required for this is first transmitted via the capillary 22a to the welded connection 29 and from there via the traction wire 27 to the welded connection 28. From there, the flux of force reaches the head 20 via the capillary 22a. The traction wire 27 thus bridges the non-tension-resistant section 25 in terms of force transmission.

[0037] It is also possible to connect the pulling element 26 to the capillary 22a only at the connection point 28 and to guide it through the entire length of the cryoprobe 11 to its proximal end. In this case, the capillary 22a can be constructed completely or in one or more sections from the proximal end to the connection point 28 as a more flexible metal or non-metal material than the rest of the capillary 22a.

[0038] It is also possible to connect the distal end of the pulling element 26 directly to the head 20, while the proximal end of the pulling element is connected to the capillary 22a via a welded connection 29 or another connection. In this case, the capillary 22a can be constructed completely or partially from the welded connection 29 or another connection location to its distal end in a material that is more flexible and less tensile than the remaining capillary 22a.

[0039] It is also possible that the capillary 22a is formed entirely or in one or more sections by a flexible, non-bending and non-tensioning torque-resistant material. In this case, the pulling element 26 is attached to the head 20 or an element connected thereto with its distal end, and its proximal end is connected to the proximal end of the cryoprobe 11.

[0040] Metal strips, wires, ropes, tubes, etc. indicating tensile strength can also be used as traction elements 26 instead of traction wires 27. Non-metal traction elements can also be used instead of metal traction elements 26, the ends of which are also connected to the capillary 22a so as to bridge at least the section 25 or a longer section of the capillary 22a or the entire capillary 22a. The traction element 26 can also be constructed from non-metallic materials or from composite materials (e.g. fiber composite materials) as monofilaments or as ropes.

[0041] In a preferred embodiment, the capillary is flexible only in its section 25. The section 25 typically has a length of 10 cm to 30 cm and is limited to the length obtained by the sum of the length of the actively bendable section of the endoscope and the maximum extension length of the cryoprobe 11 outside the endoscope 10 during use. The length dimension of the pulling element 26 is set so as to bridge at least the entire length of the flexible section 25 of the capillary 22a. In doing so, if the flexible section is not extended until this position, the pulling element 26 is fixed to the capillary 22a proximally and to the head 20 or the capillary 22a distally in a force-transmitting manner. Since the capillary 22a is soft only in the section 25 and is rigid outside there, the cryoprobe 11 can be manipulated in the usual way. It is also ensured that the pulling element 26 only restricts the cross section of the cavity 21 along a short length of the hose 18 and therefore does not significantly increase the flow resistance therein.

[0042] Figure 7 A modified embodiment of the device 11 is shown, to which the above description applies accordingly based on the reference numerals introduced. Figures 3 to 6 Compared with the device 11, according to Figure 7 The device 11 of is modified. Its hose 18 is constructed with two lumens, wherein the fluid channel 22 is arranged parallel to the lumen 21. Figure 8 An exemplary channel arrangement is shown in an enlarged cross section. Although the fluid channel 22 may include, for example, a circular cross section, the cross section of the cavity 21 may deviate from a circular shape (e.g., Figure 8 ) or may be circular.

[0043] In accordance with Figure 7 and Figure 8 In an embodiment of the device 11 of the embodiment of the present invention, the traction element 26 is again assigned to the hose 28, for example in the form of a traction wire 27, which can extend, for example, through the cavity 21 and can be connected with its distal end to the head 20 at the weld 24. The traction wire 27 can extend as far as the proximal end of the hose 18 in order to transmit the tension from there to the head 20.

[0044] Furthermore, the tension-resistant element may be considered as a traction element 26, such as, for example, a ribbon, a profiled wire, a harness, a rope, etc. The material of the traction element 26 may be metal or also non-metal, such as, for example, carbon fiber, aramid fiber, etc. As an alternative, the traction element 26 may be embedded in the wall of the hose 18. However, preferably, the traction element 26 is arranged according to Figures 3 to 8 In all embodiments of the present invention, the traction element 26 is arranged in the longitudinal direction of the instrument 11, whereby the traction element 26 is preferably arranged in a linear orientation. Preferably, the traction element does not surround the cavity 21 or the fluid channel 22, but is arranged essentially parallel thereto.

[0045] The inventive cryoprobe comprises a head 20 to which a cryogenic fluid is supplied via a capillary 22a. A hose 18 is used for the removal of the cryogenic fluid, wherein the capillary 22a extends through its lumen 21. The capillary 22a comprises a flexible section 25 bridged by a pulling element 26. In this way, a well-manipulable cryoprobe 11 is obtained which can be bent easily and to a very large extent and still transmits the tensile forces necessary for sample extraction.

[0046] Reference Mark List

[0047] 10 Endoscopy

[0048] 11 Cryoprobe

[0049] 12 Proximal end of endoscope 10

[0050] 13 Operating elements

[0051] 14 distal end of endoscope 10

[0052] 15 axis

[0053] 16 Distal end of cryoprobe 11

[0054] 17 longitudinal direction of axis 15

[0055] α Angle

[0056] 18 Hose

[0057] 19 18 far end

[0058] 20Head (Kopf)

[0059] 21 cavity of hose 18

[0060] 22 Fluid Channel

[0061] 22a Capillary

[0062] 23 The head side end of the capillary 22a

[0063] 24 Weld

[0064] 25 Segments

[0065] 26 Traction element

[0066] 27 Pull Line

[0067] 28, 29 are welded connection parts.

Claims

1. Cryoprobe (11), A flexible tube (18) is provided, the flexible tube (18) comprising a lumen (21) and the flexible tube (18) is provided at its distal end (19) with a head (20) for tissue sampling, having a fluid channel (22) which is arranged at its distal end (23) in communication with the head (20), having at least one traction element (26) which is assigned to the hose (18) and is arranged to extend over at least a portion of the length of the hose (18), in, The cryoprobe (11) is used to pull tissue frozen to the head (20) away from remaining tissue, wherein the fluid channel (22) is flexible and bendable in at least one section thereof and the cryoprobe is flexible, and wherein the at least one traction element (26) is used to transmit the tension required for sample extraction to the head (20).

2. The cryoprobe according to claim 1, characterized in that: The cryoprobe (11) is used for tissue sampling in the upper urinary tract of a patient.

3. The cryoprobe according to claim 1 or 2, characterized in that: The fluid channel (22) is formed by a capillary (22a) extending through the cavity (21) and arranged to transmit tension in the cavity (21), wherein the capillary (22a) is composed of a material whose tensile strength can be increased or decreased by treatment.

4. The cryoprobe according to claim 3, characterized in that: The capillary (22a) comprises at least one section (25) in which the tensile strength of the material is reduced compared to the tensile strength of the rest of the capillary (22a).

5. The cryoprobe according to claim 4, characterized in that: The capillary (22a) consists of steel and the at least one section (25) is softened.

6. The cryoprobe according to claim 4, characterized in that: The pulling element (26) is arranged across the at least one section (25) of the capillary tube (22a).

7. The cryoprobe according to claim 4, characterized in that: The pulling element (26) is arranged without pre-tension across the at least one section (25) of the capillary tube (22a).

8. The cryoprobe according to claim 4, characterized in that: The pulling element (26) includes two ends, at least one of which is connected to the capillary tube (22a).

9. The cryoprobe according to claim 8, characterized in that: Both ends of the pulling element (26) are connected to the capillary tube (22a) so that the pulling element (26) spans over the at least one section (25).

10. The cryoprobe according to claim 8, characterized in that: Both ends of the pulling element (26) are welded to the capillary (22a) so that the pulling element (26) spans over the at least one section (25).

11. The cryoprobe according to claim 9, characterized in that: Both ends of the pulling element (26) are connected to the capillary (22a) outside the at least one section (25).

12. The cryoprobe according to claim 9, characterized in that: Both ends of the pulling element (26) are connected to the capillary (22a) outside the at least one section (25) via welds (28, 29).

13. The cryoprobe according to claim 12, characterized in that: The weld seams (28, 29) are oriented longitudinally on the capillary (22a).

14. The cryoprobe according to claim 12, characterized in that: With reference to the cross section of the capillary (22a), the weld seams (28, 29) are arranged in the same angular position.

15. The cryoprobe according to any one of the preceding claims 1 to 2, characterized in that The traction element (26) is formed from one or more wires of high-strength steel.

16. The cryoprobe according to any one of the preceding claims 1 to 2, characterized in that The traction element (26) has a force greater than 900 N / mm 2 Formed from one or more wires of tensile strength stainless steel.

17. The cryoprobe according to claim 3, characterized in that: The pulling element (26) is arranged largely parallel to the capillary (22a).

18. The cryoprobe according to any one of the preceding claims 1 to 2, characterized in that Only one traction element (26) is arranged in the cavity (21).

19. The cryoprobe according to claim 3, characterized in that: The diameter of the pulling element (26) is smaller than the difference between the diameter of the cavity (21) and the outer diameter of the capillary (22a).

20. The cryoprobe according to claim 1 or 2, characterized in that: The hose is constructed with two cavities, the two cavities being the cavity (21) and the fluid channel (22), wherein the pulling element (26) extends through the cavity (21) or the fluid channel (22) or through the wall of the hose (18).

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