Device for connection of a cannula made from a flexible material to a tube

The invention relates to a device for connecting a flexible tube (or tube) comprising a tube according to the preamble of claim 1.

Devices for connecting cannulae and tubes are known, for example from <patcit id="pcit0001" dnum="DE4129397"><text>DE 4 129 397</text></patcit>. Thus, transfer nuts are frequently used to achieve a connection between tubes or cannulas. In this case, the coupling nut is combined with a clamping forceps or an olive (joint connection) in order to connect tubes or cannulas. When tightening the nut, a radial force is transmitted to the cannula. An axial securing and a radial seal are achieved with the coupling nut. This connection technique is currently being used in particular to connect implantable blood pumps, in which connections between a generally metallic tube with a flexible material consisting of flexible material are required.

This type of known connections between blood pump and cannula and tube has the following disadvantages:<ul><li>A thread requires larger wall thicknesses. This results in a larger diameter at the connection. Furthermore, a weight gain through more material is unavoidable.</li><li>There are no reproducible and continuous connection conditions over a long period of time. A defined tightening torque is only possible to a limited extent. The necessary use of a torque wrench would have the disadvantage that the surgeon needs a further tool for implantation and explantation. An undefined tightening torque can lead to damage to the material (silicone flows at high forces and polyester fabric as well as Dacron or PTFE can tear) or on the other hand, the nut is too loose.</li><li>In the absence of an anti-twist device, the coupling nut can be released by vibrations. This would necessarily lead to a life-threatening leak because the nut can no longer maintain the axial safety and radial seal.</li><li>The union nut usually has a fine thread. This results in a long insertion length. This means difficult handling and thus a high time expenditure for the surgeon.</li><li>The transfer nut technology has undefined and bloody transitions. There is a risk of hemolysis and thrombi.</li><li>Union nut technology is always adapted to a particular cannula material (titanium, polyester fabric PTFE, Dacron, silicone or polyurethane). Other cannula materials require other constructions.</li><li>In the currently known systems, the length adjustment of the outlet cannula to the patient anatomy can only take place at the distal end (aortic side). The free design possibility of the head of the outlet cannula is therefore no longer possible. As a result, an undefined and bloody transition can occur, for example, in the mainly used outlet cannulas of polyester fabric. Furthermore, these outlet cannulas can kinking and lead to a flow reduction in the delivery of the blood.</li></ul>

The invention is based on the object of providing a device for connecting flexible materials consisting of flexible materials with tubes which provide uncomplicated, fast, safe and reproducible conditions for connecting and uncoupling the cannula and tube, in particular under the conditions of an operative procedure Connect a heart-assisting or heart-replacing blood pump.

The object is achieved by the features of claim 1.

Thus, the device according to the invention is for connecting a cannula consisting of flexible material to a tube, wherein a tube stub attached to the tube, for example, is inserted into the cannula, characterized in that a claw ring arranged on a cannula end is slidable and rotatable Can be connected to a latching ring, which is fastened on a pipe end, by axial displacement and engagement with the latching ring.

A tensioning ring, which is fixedly connected to the cannula, is arranged on the cannula end. The claw ring is displaceable and rotatable on this clamping ring. Advantageous further developments are specified in the subclaims. The shaping and the material selection of the clamping ring advantageously make it possible to support the radial seal by generating additional radial sealing forces.

Thus, it is possible to manufacture the tensioning ring from elastic material, such as silicone, or from inflexible material, such as metal. In particular, clamping rings made of metal can also be designed as a slotted sleeve.

In a further embodiment of the invention, the stop is designed as a terminal collar at the end of the cannula so that, when the claw ring engages, the terminal collar presses against the latching ring and thus establishes a tight connection.

In a further embodiment of the invention, it is provided to arrange a spacer ring between the collar and the claw ring which presses against the collar during the latching process. When the collar is made of flexible material, a better pressure distribution is achieved by means of the spacer ring. The spacer ring can be installed both slidably and rotatably as well as fixedly connected to the claw ring.

In a further embodiment of the invention, a reinforcing part, which is fixedly connected to the cannula and on which the claw ring is arranged displaceably and rotatably, is located on the cannula end. Advantageously, the reinforcing part combines the clamping ring with the collar.

In a further embodiment of the invention, a groove is provided between the clamping ring and the collar, which groove accommodates the spacer ring. The spacer ring can have different shapes, which can result in particular from the design requirements. It is pressed into the groove by deformation of the flexible collar. Since the claw ring presses against the spacer ring and which again against the collar during the engagement process of the claw ring, the radial seal is produced by the elastically expanded cannula and the clamping ring, in this case by the axial seal with the aid of the Sealing surfaces at the collar.

It is also possible to axially seal only on the end face of the collar. The tube neck protruding into the cannula, for example an olive, can then be extremely short or can be omitted completely, so that the overall length of the heart support system can advantageously be reduced.

In a further advantageous embodiment of the invention, the claw ring has a base ring on which claws, which have claw holding surfaces, are arranged on the base ring via spring joints. The base ring may also be fixedly connected to the spacer ring.

In a development of the invention, the detent ring has retaining surfaces against which the claw holding surfaces of the claw ring abut.

In a further embodiment of the invention, the reinforcing part is made of a flexible material, preferably of the same material, from which the cannula is also made, preferably silicone.

In a further embodiment, the reinforcing part is an integral part of the cannula end, which is produced, for example, by injection molding, so that the cannula and reinforcing part are made of the same material.

In a further embodiment, the catch ring has rising surfaces which lead to spreading of the claws relative to the catch ring when the claw ring is rotated, so that the claw ring can be pulled off the catch ring after the claws have left the catch ring surface areas. The connection is unlocked.

In a further embodiment, the detent ring has a rotation limiter on which, when the claw ring is rotated relative to the detent ring, a non-expanded claw strikes and thus prevents the claw ring from being rotated beyond the unlocking position. A further identical stop can be arranged mirror-symmetrically so that the rotation in the unlocking position is limited independently of the direction of rotation of the claw ring.

In a further advantageous embodiment of the invention, the cannula has two or more reinforcing elements arranged one behind the other. This has the advantage that the cannula can be shortened during the implantation process of the pump without a further reinforcing part having to be pushed onto the cannula end.

The invention has the following advantages:<ul><li>It is possible to make a simple, quicker and more secure connection of a flexible cannula to a metal tube under the conditions of an implantation of a blood pump, this connection being releasable by rotation of the claw ring and the axial withdrawal of the claw ring and the cannula.</li><li>There is only a small increase in the outer diameter at the connection point between the cannula and the tube, compared to the outer diameter of the cannula or the tube, which is associated with a lesser weight.</li><li>There are reproducible connection conditions.</li><li>A separation of the axial securing and the radial and / or axial seal takes place in comparison to a coupling nut connection. The axial securing against separation of the connection is ensured by the claw ring. The radial or axial seal is achieved by means of optimized diameter ratios or thickness ratios at the pipe connection (olive) and at the cannula. As a result, no undefined axial or radial force is applied to the cannula, ie there is no additional negative influence on the cannula material. Furthermore, an additional anti-rotation device is eliminated, since the claw ring would have to be twisted in order to release the connection, which would require a torque which could cause spreading of the claws by sliding on the rising surfaces of the latching ring. This torque would only be applied by the surgeon if required. There is therefore self-assurance.</li><li>The snap-in connection according to the invention makes it possible to achieve an ideal, and thereby blood-chilling, transition from cannula to tube. The connection between the pipe stub, which is designed as an olive, usually made of titanium, and the cannula has practically no flow impediments.</li><li>The device according to the invention functions in any known cannula material without the need for major structural changes.</li><li>No special tool is required for the connection and uncoupling of the device according to the invention.</li><li>The length adjustment of the outlet cannula is effected at the pump-side end by cutting off the unnecessary reinforcing formations. The claw ring is then pushed back onto the cannula and the spacer is knotted into the groove closest to the cannula end. This makes possible a free design possibility of the outlet end of the outlet cannula.</li></ul>

The invention is explained in more detail by means of an exemplary embodiment and drawings.

Show it<dl id="dl0001"><dt>FIG</dt><dd>A schematic axial sectional view of a cannula end before the joining, </dd><dt>FIG</dt><dd>A schematic axial sectional view of the pipe end before the joining,</dd><dt>1c</dt><dd>A schematic, axial sectional view of the assembly according to the invention of the cannula end with the tube end,</dd><dt>FIG</dt><dd>A claw ring in a perspective view,</dd><dt>3 a</dt><dd>An axial sectional representation of a cannula end with a spacer ring,</dd><dt>FIG. 3 b</dt><dd>An axial representation of a cannula end with cannula reinforcement without spacer,</dd><dt>FIG. 3 c</dt><dd>An axial sectional representation of a spacer ring,</dd><dt>FIG. 4 a</dt><dd>A locking ring in a perspective view in the direction of the tube end,</dd><dt>FIG. 4 b</dt><dd>A locking ring in a perspective view in the direction of the end of the cannula,</dd><dt>FIG. 5 a</dt><dd>An axially cut claw ring,</dd><dt>FIG. 5 b</dt><dd>An axially cut detent ring,</dd><dt>FIG. 5 c</dt><dd>An axially cut claw ring and latching ring in the locked state,</dd><dt>FIG. 6 a</dt><dd>An arrangement of the claws when pushed onto the latching ring (latching position),</dd><dt>FIG. 6 b</dt><dd>The arrangement of the claws on the detent ring after a rotary movement of the claw ring in the unlocking position, a claw not spreading being applied to the rotation limiter and thus defining the unlocked position, </dd><dt>7a</dt><dd>An arrangement of a plurality of cannula reinforcements on a cannula,</dd><dt>7b</dt><dd>An embodiment of a cannula with reinforcing form integrally connected to the cannula by injection molding,</dd><dt>8a</dt><dd>A representation of the cannula end with collar and claw ring,</dd><dt>FIG. 8b</dt><dd>A representation of the pipe end with latching ring,</dd><dt>8c</dt><dd>3 shows a representation of the connection of a cannula end with a tube end with a stop at the cannula end, FIG.</dd><dt>9a</dt><dd>A representation of a cannula end with collar and tensioning ring as well as spacer ring,</dd><dt>9b</dt><dd>A representation of a pipe end with latching ring,</dd><dt>9c</dt><dd>A representation of the connection between the cannula end and the tube end with collar, clamping ring and spacer ring,</dd><dt>10a</dt><dd>A representation of a cannula end with a narrow collar and claw ring,</dd><dt>10b</dt><dd>A representation of a pipe end with a shortened pipe connection,</dd><dt>10c</dt><dd>An arrangement of the connection between the end of the cannula and the tube end with a shortened tube connection,</dd><dt>11a</dt><dd>7 shows a schematic representation of a heart support pump with the connection positions according to the invention with outlet manifolds and FIG </dd><dt>11b</dt><dd>A heart support pump with connection positions and an outlet cannula with several reinforcing elements.</dd></dl>

FIGS. 1a, 1b, 1c show, by way of example, a device according to the invention which establishes a connection between a cannula 7 and a tube 5. A pipe socket, in this case designed as an olive 4, is inserted into a cannula end 71 (FIG. 1c). A reinforcing part 6 is fixedly connected to the cannula end 71 on the cannula end 71. A spacer ring 2 is arranged in a groove 61 of the reinforcing part 6. A claw ring 1 with its claws 11 attached to a base ring 15 (see FIG. 2) is latched on the detent ring 3. The claw ring 1 in this case presses on the spacer ring 2 and this on a collar 62 of the reinforcing part 6 so that a tight connection is produced with an annular end face 36 of the catch ring 3. The sealing of the cannula 7 against the olive 4 takes place by the elastic expansion of the cannula end 71 when it is pushed onto the olive 4, as a result of which radial sealing forces are produced which press the inner surface of the cannula end 71 onto the olive 4. The radial sealing force is further increased by the clamping ring 63 of the reinforcing part 6.

The device according to the invention is a snap connection in its principal function. The claws 11 attached to the base ring 15 are pushed over the latching ring 3 and snap into place again releasably (see FIG. 2, FIG. 5 and FIG. 6).

The end face 36 extends radially outwards into a rising surface 31 and radially inwards into an opening 35. This serves to receive the cannula projection 72, possibly occurring during the implantation, when the cannula is shortened in front of the collar (FIG. 7). Behind the end face 36 are holding surfaces 32 and rising surfaces 33 into which the claw ring 1 located on the cannula 1 snaps with the claws 11 and thus connects the cannula 7 with the tube 5. The spacer ring 2 and the claw ring 1 for the connection of the cannula 7 can already be pre-mounted on the cannula 7 in the delivered state, or can be mounted on the cannula 7 during the operation. The cannula 7 is pushed onto the olive 4, the inner diameter of the cannula 7 being expanded elastically. The claw ring 1 is rotated so far, (FIG. 6a) and then axially displaced in the direction of the detent ring 3. In the embodiment shown in FIG. The claws 11 are splayed on the snap ring surface surfaces 31 of the snap ring 3 when pushed on and snap into the snap ring holding surfaces 32 with claw holding surfaces 12 (FIGS. 5 a, 5 b, 5 c).

In the perspective view of the claw ring 1 according to FIG. 2, six claws 11 are arranged on a base ring 15. At the end of the claws 11, the claw holding surface 12 and a claw surface 14 are provided. These are provided for secure engagement in the detent ring 3, as shown in FIGS. 5 a, 5 b and 5 c. Spring joints 13 of the claw ring 1 permit the spreading apart of the claws 11 on the catch ring 3 during the snap action.

The cannula end 71 of the cannula 7 is shown in FIGS. 3a, 3b and 3c. 3a, the reinforcing part 6 is applied to the cannula end 71 and the spacer ring 2 is seated in the groove 61 of the reinforcing part 6. FIG. 3b shows the cannula end 71 without spacer ring 2 but with reinforcing part 6 with the formed clamping ring 63, collar 62 and groove 61. FIG. 3c shows the spacer ring 2, which can be positively inserted into the groove 61 of the reinforcing part 6.

FIGS. 4a and 4b show a single detent ring 3, on which detent ring surfaces 31, detent ring holding surface 32, unlocking platform surfaces 33, a rotational limit 34, an opening 35 and an end face 36, which can serve as an axial sealing surface. FIG. 4a shows the view in the direction of the tube 5 and FIG. 4b the view in the direction of the cannula 7.

5a, 5b and 5c, a claw ring 1 and a detent ring 3 are shown once in the non-engaged or non-disengaged state (FIGS. 5a and 5b) and once in the locked-in or snapped-in state (FIG. 5c). The cooperation between the spring joint 13 of the claw holding surface 12 and the claw climbing surface 14 of the claw ring 1 with the climbing surface 31, the retaining surface 32, the climbing surface for unlocking 33 and the release 35 can be seen here again.

FIG. 6a shows the locked-in state (latching state) after the claw ring 1 has been pushed onto the catch ring 3. By rotating the claw ring 1 up to a rotation limit 34, the unlocking position is reached, the claws 11 being spread by sliding on the unlocking surface surfaces 33 of the detent ring 3 (FIG. 6b). The claw ring 1 can now be withdrawn axially from the detent ring 3 and the cannula 7 from the olive, thus releasing the connection.

FIGS. 7a and 7b show the arrangement of a plurality of reinforcing parts 6 on the cannula 7 for the advantageous adjustment of the length during implantation. Depending on the anatomical situation, the length of the cannula 7 is shortened by cutting off a certain number of the reinforcing parts 6 during the operation. 7b shows a cannula, the reinforcing parts 6 of which are an integral component of the cannula (injection-molding production). The cannula projection 72, which may be formed in this case, protrudes when the cannula 7 and the tube 5 are inserted into the opening 35.

The possible interfaces for adapting to the size ratios during implantation are indicated by AB and CD.

FIGS. 8 a, 8 b and 8 c show a further variant of the device according to the invention. FIG. 8a shows the cannula end 71 of the cannula 7 with latching ring 1 and the collar 62, which is formed here directly at the cannula end 71. In this variant, a reinforcing part 6 is not provided.

FIG. 8b shows the pipe end 51 of the pipe 5, which has the catch ring 3 and the olive 4. By inserting the olive 4 into the cannula end 71, a tight connection between the two is produced by the latching of the claw ring 1 on the latching ring 3. The collar 62 is here relatively wide, so that at the same time a reinforcement of the radial sealing forces takes place in conjunction with the axial sealing on the contact surfaces of the ends.

FIGS. 9a, 9b and 9c show a further embodiment of the device according to the invention. Instead of a closed reinforcing part 6, the arrangement of a separate collar 62, clamping ring 63 and spacer ring 2 is provided here. Also with this variant, a tight connection and sealing is achieved.

FIGS. 10 a, 10 b and 10 c show a further embodiment of the device according to the invention. In this case, the olive 4 is clearly shortened, while the catch ring 3 has a wider shape.

FIGS. 11a and 11b schematically illustrate the use of the device according to the invention on an implantable blood pump.

Thus, FIG. 11a shows a blood pump 8 which has the olives 4 at its outlets and inlets. A fixed connection can be established by means of the device according to the invention by the latching of the claw ring 1 on the catch ring 3 to the outlet manifold 83. On the other side of the pump 8, an inlet cannula can also be connected to the pump by engaging the claw ring 1 on the detent ring 3. In addition, it is possible to connect the outlet manifold at its other end to a so-called outlet cannula 81, in particular the great advantage of the device can be seen in the illustration according to FIG. 11a. The optimum position can be achieved by twisting the elbows without the connectivity with the pump 8 being impaired in any way.

FIG. 11b shows the connection of the pump 8 to the olives 4 with the outlet cannula 81 and the inlet cannula 82 without outlet manifold 83. The outlet cannula 81 has a plurality of reinforcing parts 6 arranged one behind the other at the cannula end 71 (FIGS. 7a and 7b).

The application advantageously takes place, in particular, in the case of a blood pump 8 which is implanted in the body and which must be connected with inlet and outlet cannulas 82 and 81. Both inlet and outlet cannulas 82 and 81 are connected to the pumping system via the snap connector according to the invention. The blood coming from the heart is supplied via the inlet cannula 82 to the blood pump 8 and fed from the blood pump 8 via the outlet cannula 81 to the aorta, which is not shown here. Inlet and outlet cannulas 82 and 81 are connected to the blood pump 8 via the device according to the invention. The outlet manifold 83 can alternatively be inserted between the blood pump 8 and the outlet cannula 81. Its inlet is designed like a cannula end 71 and can thus also be fastened to the pump outlet with a snap-on connector.

During the implantation of the cardiac support system, it is possible to achieve an adaptation of the system to the respective physical size ratios by cutting off at least one reinforcing part 6, as shown in FIG. 7a. The claw ring 1 and the spacer ring 2 (FIG. 1) can be easily pushed onto the subsequent reinforcing molding part 6 by appropriately deforming the elastic material.

Reference list

<dl id="dl0002" compact="compact"><dt>1</dt><dd>Claw ring</dd><dt>11</dt><dd>claw</dd><dt>12</dt><dd>Claw holding surface</dd><dt>13</dt><dd>Spring joint</dd><dt>14</dt><dd>Claw surface</dd><dt>15</dt><dd>Basic ring</dd></dl><dl id="dl0003" compact="compact"><dt>2</dt><dd>Spacer ring</dd></dl><dl id="dl0004" compact="compact"><dt>3</dt><dd>Locking ring</dd><dt>31</dt><dd>Resting ring surface</dd><dt>32</dt><dd>Restraining surface</dd><dt>33</dt><dd>Unlocking platforms</dd><dt>34</dt><dd>Limitation of rotation</dd><dt>35</dt><dd>Franking</dd><dt>36</dt><dd>End face</dd></dl><dl id="dl0005" compact="compact"><dt>4</dt><dd>olive</dd></dl><dl id="dl0006" compact="compact"><dt>5</dt><dd>pipe</dd><dt>51</dt><dd>Pipe end</dd></dl><dl id="dl0007" compact="compact"><dt>6</dt><dd>Reinforcing part</dd><dt>61</dt><dd>Nut</dd><dt>62</dt><dd>Federation</dd><dt>63</dt><dd>Clamping ring</dd><dt>64</dt><dd>Waist area</dd></dl><dl id="dl0008" compact="compact"><dt>7</dt><dd>Cannula</dd><dt>71</dt><dd>End of cannula</dd><dt>72</dt><dd>Cannula neck</dd><dt>73</dt><dd>Disconnection point</dd></dl><dl id="dl0009" compact="compact"><dt>8th</dt><dd>Blood pump</dd><dt>81</dt><dd>Outlet cannula</dd><dt>82</dt><dd>Inlet cannula</dd><dt>83</dt><dd>Exhaust manifold</dd></dl>