Abstract
In various exemplary embodiments, a modular cannula device is provided that has an external, tubular cannula, a first tubular guide part which has a tapering distal end and can be inserted into the cannula so that its outer wall rests tightly against the inner wall of the cannula, and a second tubular guide part, which has a tapering, pointed distal end and can be inserted into the first guide part so that its outer wall rests tightly against the inner wall of the first guide part.
Claims
1. Modular cannula device comprising: an external tubular cannula; a first tubular guide part that has a tapering distal end and can be inserted into the cannula so that its outer wall rests tightly against the inner wall of the cannula, and a second tubular guide part which has a tapering, narrowing distal end and can be inserted into the first guide part so that its outer wall rests tightly against the inner wall of the first guide part.
2. Modular cannula device according to claim 1, wherein the opening angle of the tapering distal end of the first guide part is greater than the opening angle of the tapering distal end of the second guide part.
3. Modular cannula device according to claim 1 or 2, wherein the first tubular guide part has an enlarged region at the proximal end with an external diameter that is greater than the internal diameter of the tubular cannula.
4. Modular cannula device according to any one of claims 1 to 3, wherein the first and second guide parts each have a part of a fixing device at the proximal end, by means of which the second guide part can be fastened to the first guide part relative thereto.
5. Modular cannula device according to claim 4, wherein the fixing device comprises a female thread arranged in the first guide part and a matching male thread arranged on the second guide part.
6. Modular cannula device according to any one of claims 1 to 5, wherein, when the modular cannula device is in an assembled state, it may have a tapering distal end formed at least by the tapering ends of the first and second guide parts.
7. Modular cannula device according to any one of claims 1 to 6, wherein a radiopaque marker is arranged in the region of the distal end of the tubular cannula, which is preferably designed as a completely circumferential ring in the lateral surface of the cannula.
8. Modular cannula device according to any one of claims 1 to 7, wherein the distal end region of the cannula, which is preferably at least 2 cm long, is made of a softer material than the remaining part of the cannula.
9. Modular cannula device according to any one of claims 1 to 8, wherein the cannula is made of a softer material than the first guide part.
10. Modular cannula device according to any one of claims 1 to 9, wherein the material is provided with a pretensioning in at least one part in the distal region of the cannula so that the corresponding part of the cannula has an arcuate shape without an external force being applied.
Description
[0029] The figures show schematically:
[0030] FIG. 1 a perspective side view of an exemplary embodiment of the distal end of the external cannula,
[0031] FIG. 2 a perspective side view of an exemplary embodiment of the distal end of the first guide part,
[0032] FIG. 3 a perspective side view of an exemplary embodiment of the distal end of the second guide part,
[0033] FIG. 4 a perspective side view of the distal end of the cannula device in the assembled state,
[0034] FIG. 5 a side view showing the proximal end region of the external cannula into which the first guide part is inserted,
[0035] FIG. 6 a perspective side view of the proximal end of the second guide part of the cannula device,
[0036] FIG. 7 a representation of an exemplary position of the cannula device in a ventricle of the heart,
[0037] FIG. 8 a diagram illustrating the pretensioning of the cannula,
[0038] FIG. 9 a diagram in which an exemplary location is illustrated of the cannula device with a balloon catheter that has been guided through during implantation.
[0039] FIG. 1 shows a perspective side view of an exemplary embodiment of the distal end of the exterior cannula of the cannula device 10. In the example shown, the cannula 10 has a cylindrical or tubular basic shape 11 and has an opening 15 at the distal end. The round cross-section of the cannula 10 may generally have a different geometric shape and may be round or oval, for example, or resemble a regular polygon (e.g., pentagon, hexagon, octagon, etc.). Rings 12 of radiopaque material are arranged in the wall of the cannula 10. One of the rings is located directly at the distal end of the cannula 10 so as to define the opening 15 in the cannula 10. The other ring 12 is arranged at a distance from the opening 15. Provided in the wall of the cannula 10 are lateral holes 14, the position, number and size of which can be selected depending on the intended use of the cannula device according to the invention. Furthermore, a coil 13 is provided around the outer wall of the cannula 10 and assumes the function of a reinforcing or stiffening structure. The material from which the coil 13 is made may preferably be stiffer than the material from which the wall of the cannula 10 is made. A distal region of the cannula 10 extending between the distal end of the coil 13 and the distal opening 15 of the cannula 10 is not reinforced/stiffened and is therefore more flexible/pliable than the part of the cannula 10 reinforced by the coil 13. Furthermore, a flow sensor 16 is mounted in the distal region of the cannula 10 by means of which a fluid flow present on the distal wall of the cannula can be examined. Data are transmitted and power is supplied to the flow sensor 16 by means of (at least) one line 17 running on the outer wall (or even within the outer wall).
[0040] FIG. 2 shows a perspective side view of an exemplary embodiment of the distal end of the first guide part 20. The first guide part 20 has a substantially cylindrical basic shape narrowing or tapering in the distal region 21 toward the distal end 22. Just as in the case of the exterior cannula (see FIG. 1), an opening is also provided here at the distal end 22. In other words, the first guide part 20 (just like the exterior cannula 10 shown in FIG. 1) is hollow in the interior. The first guide part 20 is dimensioned such that it can be inserted into the cannula 10 shown in FIG. 1. By adapting the dimensions of the two modules to one another, the contact surface between the two modules is tight, so that no fluid (in particular blood) can pass therethrough. The internal diameter of the cannula 10 and the geometric shape of its cross-section therefore correspond to the external diameter or geometric shape of the cross-section of the first guide part 20. In addition, a top view of the distal region 21 of the first guide part 20 is illustrated at top right in FIG. 2.
[0041] FIG. 3 illustrates the distal end region of the second guide part 30. The second guide part 30 has a structure that is basically similar to the first guide part 10 (while initially ignoring the smaller diameter). That is to say, the second guide part 30 also has a substantially cylindrical basic shape that narrows or tapers in the distal region 31 toward the distal end 32. The distal end 32 terminates with an opening located at the distal end of the hollow channel extending through the interior of the second guide part 30. Analogously to the configuration of the first guide part 20 with respect to the cannula 10, the second guide part 30 is dimensioned such that it can be inserted into the first guide part 20 shown in FIG. 2. The contact area between these two modules is also tight so that no fluid (in particular blood) can pass therethrough. This can be slid on a guide wire through the opening at the distal end 32 of the second guide part.
[0042] In FIG. 4, a perspective side view is shown of an exemplary embodiment of the distal end of the modular cannula device 40. In the assembled state which corresponds to the implantation state, the second guide part 30 is arranged within the first guide part 20, and the first guide part 20 is in turn arranged within the cannula 10 as the outermost module of the cannula assembly 40. In the assembled, ready-to-use state, the modules are arranged relative to one another such that the distal end region 21 of the first guide part protrudes out of the opening 15 at the distal end of the cannula 10 and, at the same time, the distal end region 31 of the second guide part protrudes out of the opening at the distal end of the first guide part 20. By means of corresponding fixing or locking mechanisms, such a configuration of the modules of the cannula assembly 40 can be fixed so that it is automatic, i.e., without a physician having to hold the modules relative to each other. That is to say, the modules in each case in contact with each other can be connected to each other in pairs so that during a surgery, this configuration is maintained and the entire cannula device 40 can be moved as a unit. A fixing or locking mechanism independent of the other mechanism can be provided in each case between two of the three components. In particular, in the assembled state, the modules can be positioned relative to one another in such a way that the distal end regions 21, 31 of the first and second guide parts 20, 30 merge into one another smoothly and “gradually”, in particular step-free or edge-free. In other words, a continuously smooth surface may result from the edge of the opening 15 at the distal end of the cannula 10 up to the opening at the distal end of the second guide part 30. As shown in FIG. 4, the slopes of the lateral surfaces of the conically narrowing distal end regions 21, 31 of the guide parts 20, 30 may be different. In particular, these production parameters can be optimized/adapted for the particular type of operation in which the cannula device according to the invention is to be used. In addition, a connecting line between a first point 41 at the edge of the opening 15 and a second point 42 at the opening at the distal end of the second guide part 30, when viewing the cannula device 40 in a longitudinal cross-section, need not necessarily be straight, but may have a curvature. For example, the connecting line between the two points 41 42 may have a concave or convex curvature.
[0043] FIG. 5 shows a side view in which the proximal end region of the external cannula 10 with a first guide part 20 inserted therein is illustrated. At its proximal end, the first guide part 20 has a thickened region 23 with an outer diameter which is greater than the diameter of the hollow channel in the interior of the cannula 10. The thickened region 23 is formed as a radial projection 24 which can project over the entire circumference or only segmentally from the outer wall of the first guide part 20. The projection 24, which lies against the edge of the proximal end of the cannula 10, prevents the first guide part 20 from being inserted too deeply into the cannula 10. In the present case, the projection 24 has an indentation 25 at its distal end (or the segments arranged along the circumference of the first guide part 20 have corresponding indentations) which receives the edge region of the proximal end of the cannula 10. The length of the first guide part 20 can be selected such that, upon the engagement of the edge region of the proximal end of the cannula 10 in the indentation 25, the first guide part 20 assumes a position opposite the cannula 10 as shown in FIG. 4. In addition, the first guide part 20 has a female thread 26 which is arranged at the proximal end of the first guide part 20.
[0044] In FIG. 6, a perspective side view of the proximal end region of the second guide part 30 of the cannula device 40 is shown. At the proximal end, a grip region 34 is provided, which is mounted upstream of a male thread 33. The male thread 33 is formed such that when the second guide part 30 is pushed into the first guide part 20, it can be screwed into the female thread 26 of the first guide part 20. The male thread 33 and the female thread 26 provide two parts of a fixing device by means of which the two guide parts can be connected to one another. At the same time, the maximum insertion depth of the second guide part 30 into the first guide part 20 can be defined. In the lower right corner of FIG. 6, an underside view of the proximal end of the second guide part 30 is additionally shown. The proximal end has an opening 35 which preferably has the same diameter as the opening at the distal end 31 of the second guide part 30.
[0045] The fixing device, designed as a threaded device by way of example, represents only one of many possibilities of how the two guide parts 20, 30 can be connected to one another. For example, a latch-turn lock may also be used. In general, the fixing device represents an optional feature which can also be omitted entirely. Instead, the grip region, which represents a thickened region in relation to the remaining part of the second guide part 30, can function as a limit for the insertion depth of the second guide part 10 into the first guide part 20. At a maximum insertion or push-in depth of the second guide part 30 into the first guide part 20, the guide parts 20, 30 can assume the position shown in FIG. 4 relative to one another.
[0046] In the representation in FIG. 7, an exemplary location is illustrated of the cannula device 40 during a percutaneous implantation process through the right ventricle 70 of the heart. As shown, the cannula device 40 extends arcuately between the tricuspid valve 71 and the pulmonary valve 72. During the operation in which the cannula device 40 is advanced through the corresponding veins and through the two heart valves 71, 72 of the right ventricle 70 into the right ventricular outflow tract, the placed guide wire or balloon catheter predefines the shape of the cannula device 40 according to the invention. In other words, when the cannula device 40 is advanced along the guide wire or balloon catheter, its shape follows the course of the guide wire. After the cannula device 40 has assumed its final position at which the external cannula 40 is to remain, the two-part guide part 20, 30 (or even only the first guide part 20 still remaining in the cannula 10) is withdrawn from the cannula 10. In this case, the cannula 10 can assume its native shape and curve, for example, as shown in FIG. 8, arcuately to conform to the anatomy of the right ventricle 70. The angle 18 between the legs of the arcuate or round V-shape may lie within a range from about 10° to about 25°, preferably within a range from about 10° to about 15°. The arcuate shape can be produced by a material pretensioning introduced during production, in that the cannula 10 is made of a shape-memory polymer at least in the relevant sub-region. As a result, the solitary cannula 10 automatically assumes the arcuate shape provided for it and exerts no or only minimal pressure on the inner wall of the heart. Discomfort to the patient during the time the cannula 10 is in place can thus be prevented or at least greatly reduced.
[0047] FIG. 9 shows a diagram illustrating an exemplary location of the cannula device 40 with a through-guided balloon catheter 42 during implantation. In the exemplary scenario shown, the second guide part 30 has been removed from the cannula device 40 and a balloon catheter 42 has been inserted instead, with which a guide path can be created out of the right ventricle 70 upward to and through the pulmonary valve 72 into the right ventricular outflow tract 73. The cannula device 40 can then be slid out of the right ventricle 70 along this guide path and into the right ventricular outflow tract 73.
[0048] In conclusion, it should be noted that the present description has only been formulated by way of example in light of the right ventricular assist device as a primary example of the use of the cannula device according to the invention. This exemplary application by no means constitutes a limitation on the intended use of the cannula device according to the invention. Rather, the use of the modular cannula device according to the invention is advantageously possible in all operations in which a cannula is to be placed in a vessel and/or organ of the patient.
