Abstract:
A method and a device for mixing at least two liquid components of different viscosities of a multi-component material, such as a tissue adhesive, during application thereof, are disclosed, the components being pressed out of separate containers, mixed, and applied by aid of an application part, e.g. a cannula, the less viscous component being directly pressed into the flow of at least one other, more viscous component.

Description:
FIELD OF INVENTION 
     The invention relates to a method for mixing at least two liquid components of different viscosities of a multi-component material, such as a tissue adhesive, during application thereof, the components being pressed out of separate containers, mixed, and applied by aid of an application part, e.g. a cannula. 
     Furthermore, the invention also relates to a device for mixing at least two liquid components of different viscosities of a multi-component material, such as a tissue adhesive, during application thereof, said device comprising separate component entrances provided in spaced relationship from each other, a mixing region, and an exit. 
     BACKGROUND 
     From AT 379 311 B, a device for applying a tissue adhesive is known in which the two components of the tissue adhesive, i.e. thrombin, on the one hand, and fibrinogen, on the other hand (or, strictly speaking, solutions thereof), by means of a double-syringe reach a device designed as a one-piece collecting head or connecting head, where the two components are supplied to a mixing cannula, or a mixing catheter via separate channels, together with a gas used for mixing. In the mixing cannula, or mixing catheter, respectively, thus the two components are mixed if required; in doing so, the gas is continuously supplied so as to keep clear the individual conveying channels whenever the tissue adhesive components are not being supplied. 
     A device for applying a multi-component tissue adhesive which is similar as regards mixing of the components by using a gas furthermore is known from EP 669 100 A, that device being provided for spray application of the tissue adhesive. To this end, the components are mixed immediately downstream of the front side of the connecting body designed with various channels, and atomized by aid of a medicinal gas. 
     In contrast to these known devices, more and more often a mixture of the components without the assistance of a medicinal gas is desired. Thorough mixing of the components without an early clot formation causing blocking of the passages poses substantial problems. From U.S. Pat. No. 5,116,315 A, a double syringe is known which has a connecting head having entrances connected to the delivery ends of the syringes and having a forward end side facing away from the syringes provided with a conical spray top latchingly engaging with the connecting body and in which a flat, disk-shaped mixing space is formed into which the conveying channels for the tissue adhesive components end at the outer periphery thereof, and from which centrally an axial exit leads away. On this top, a cannula, e.g., can be put. The design of this device may allow formation of clot within the device which would lead to clogging. 
     It is now an object of the invention to eliminate these problems and to provide a method and an arrangement, respectively, of the initially defined kind with which a reliable mixing of the components of a multi-component material is obtained without premature solidification, wherein also the supply of a medicinal gas is no longer necessary. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The method according to the present invention is characterized in that the less viscous component is directly pressed into the jet or flow of at least one other component having a higher viscosity. 
     In corresponding manner, the device of the present invention is characterized in that the entrance for the less viscous component is followed by a guiding part for pressing the less viscous component directly into a flow passage for the more viscous component, which flow passage leads from the entrance to the exit. 
     According to the present invention, thus, the less viscous component is actively pressed into the other, more viscous component, e.g. by injecting a jet of the less viscous component directly into the jet or flow of the more viscous component. This ensures good mixing of the two components, the more viscous component being entrained by the less viscous component—which preferably is pressed in at an approximately right angle to the flow direction of the more viscous component. Since subsequently the component jet or flow may immediately be supplied to the exit or to the applicator tip respectively, with dead spaces being avoidable without any problem, undesired clot formation is avoided. Before the less viscous component is pressed into the jet or flow of the more viscous component, the less viscous component may deliberately be delayed so that the two components will arrive practically simultaneously in the mixing region despite the higher flow rate of the less viscous component due to its lower viscosity. This delay could as such be attained by a delayed supply of the component to the entrance, e.g. by a delayed pressing out of a syringe body as compared to the other, more viscous component. As regards the device itself, an embodiment of the device according to the invention which is particularly advantageous as regards such a delay is characterized in that the guiding part simultaneously defines a delaying path for the less viscous component. Here, the guiding part will guide the less viscous component on a longer path, the delaying path, as far as to the flow passage for the highly viscous component, i.e. the flow paths for the different components of the multi-component material are differently configured. 
     In connection with the delay of the less viscous component, it may also be suitable if the entrance for the less viscous component has a smaller passage cross-section than the entrance for the more viscous component. Namely, if the piston paths from the commonly used syringe bodies are equal at a simultaneous actuation of the syringe pistons and corresponding component amounts are pressed out, by the narrowing of the entry channel for the less viscous component, i.e. the smaller passage cross-section, a higher velocity and thus energy of the less viscous component can be attained so that the latter, despite a longer flow time caused by the delay on or in the guiding part, respectively, nevertheless will enter into the jet or flow of the highly viscous component with a sufficiently high energy so as to ensure thorough mixing. 
     Preferably, the less viscous component is delayed as mentioned before, by being detoured, or deflected, respectively, so as to compensate the lower flow velocity of the other component given on account of its higher viscosity. Preferably, the jet of the less viscous component can be deflected on a guiding surface or impacting surface for the purpose of retarding it. In doing so, the jet of the less viscous component impacts on the guiding or impacting surface and is deflected by the latter to the preferably substantially straight-line jet or flow of the more viscous component. 
     On the other hand, however, it is also possible to attain the delay by pressing the jet of the less viscous component into a blind tube arranged adjacent the jet or flow of the more viscous component and having at least one lateral nozzle opening at a distance from the forward, closed end face and through at least one lateral nozzle opening into the jet or flow of the more viscous component. The less viscous component enters the blind tube, passes as far as to the closed forward end face and only then emerges through at least one lateral nozzle opening so as to get into the jet or flow of the more viscous component. By the length of the blind portion of the tube, i.e. the distance of the nozzle opening(s) from the forward, closed end face, the time of the delay can be fixed. 
     An advantageous embodiment of the device according to the invention is characterized in that the guiding part defines an angularly arranged, optionally curved guiding face for deflecting the jet of the less viscous component towards the flow passage for the more viscous component. On the other hand, in terms of construction, it may advantageously be provided that a blind tube is provided as a guide part adjacent the flow passage for the more viscous component, which blind tube, at a distance from its forward, closed end face, has at least one nozzle opening ending in the flow passage for the more viscous component, the blind tube being connected with the inlet for the less viscous component. The flow passage for the more viscous component may also be formed by a cannula or a cannula holder, by a flexible tube or also by a channel in a connecting head. 
     The device according to the present invention may advantageously comprise a one-piece collecting or connecting head with a connecting part for a cannula or a catheter, in particular a double lumen catheter, the guiding part being provided in the region of the connecting part. For a simple production it is particularly advantageous if the guiding face is moulded to the forward end face of the connecting head and opens towards the mixing region which is outwardly delimited by a cannula holder slipped thereto. For completing the application device, preferably the entrances of the device moreover are connected with discharge parts of syringe bodies; in this case, the syringe bodies contain the different components of the multi-component material. 
    
    
     In the following, the invention will be explained in more detail by way of advantageous exemplary embodiments illustrated in the drawings, to which, however, it shall not be restricted. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an exploded view of a device for mixing the components of a tissue adhesive, comprising a one-piece connecting head and a cannula holder which can be slipped thereto and includes a cannula, these two parts being illustrated in section; in addition, in FIG. 1 the ends of syringe bodies in which the tissue adhesive components are contained are shown in dot-and-dash lines; 
     FIG. 2 shows a top view onto the connecting head according to line II of FIG. 1; 
     FIG. 3 shows a side view of a front-side end region of the connecting head according to line III in FIG. 1, to illustrate the conical, roof-shaped guiding part at the end side of the connecting head; 
     FIG. 4 shows the region of the connecting head with the guiding part and the slipped-on cannula holder in section, to illustrate the mode of action of the present device; 
     FIG. 5 shows a section of a further mixing device including a connecting head and a cannula holder; 
     FIG. 6 shows yet another, present particulary preferred mixing device, in this instance with a slipped-on catheter in a comparable sectional representation; 
     FIG. 7 shows a cross-section through a fourth embodiment of the present mixing device, according to line VII—VII of FIG. 8; and 
     FIG. 8 shows an axial section through the essential part of this mixing device of FIG. 7, in accordance with line VIII—VIII of FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As an essential element, the mixing device according to FIG. 1 comprises a one-piece, synthetic material injection-moulded connecting head  1  which has a joining part  2  with plug-in coni  3  which are, or will be, put on Luer-type coni  4  of first syringe body  5  or second syringe body  6 , respectively. The connecting head  1  is provided with first channel  7 , and second channel  8  in the form of channels leading away from plug-in coni  3  and provided for the different components contained in the first syringe body  5 , and second syringe body  6  to be mixed with each other; in particular, the components are tissue adhesive components, i.e. a fibrinogen component which has a relatively high viscosity and is contained in second syringe body  6 , and from there gets to second channel  8 , and a thrombin component of relatively low viscosity which is contained in first syringe body  5  and is pressed via first channel  7  through the connecting head  1 . 
     The first and second channels  7  and  8 , respectively, continue through the connecting head  1  as far as to its connecting part  9 , which, on its outer side, is slightly conically designed and acts as a slip-on conus for the inner conus  10  of a cannula holder  11 . The cannula holder  11  in a per se common manner carries a cannula  12  only partly illustrated in FIG.  1 . Just like the connecting head  1 , the cannula holder  11  may also be made in one piece of a synthetic material conventionally used in medicine, such as, e.g., a polyolefin (polyethylene, polypropylene), polyurethane, PVC or ABS (acrylonitrile-butadiene-styrene). These parts  1 ,  11  preferably may be injection moulded. 
     To the end side of the connecting head  1 , following the end face  13 , where first and second channels  7 ,  8  have their exits, a guiding part  14  is moulded which has the shape of a cut-off cone, its inner side constituting a guiding face  15  to the thrombin component jet emerging from first channel  7 . The cut-out of the conical guiding part  14  which has the shape of a quarter-circle sector, is particularly visible from FIG. 2 in top view at  16 , cf. also FIGS. 1 and 3. 
     In FIG. 4, that region of the present device which is essential for mixing of the two components is illustrated in the instance of operation. Through second channel  8 , the fibrinogen component is forced, and through first channel  7 , the thrombin component is forced, in conventional manner by inward movement of syringe pistons not illustrated in FIG. 1 into first and second syringe bodies  5 ,  6 . In FIG. 4, the jet of the thrombin component, in general the less viscous component, is illustrated at  17 , and the jet or flow of the fibrinogen component is illustrated at  18 . In a mixing region  19 , these two components are mixed, i.e. by deflecting the comparatively less viscous component  17  on the guiding face  15  of the guiding part  14  and actively introducing or pressing it with a certain energy into the jet of flow  18  of the more viscous component. By this deflection or detour of jet  17  on the guiding face  15 , a delaying path is obtained so that the less viscous component is also somewhat delayed, whereby the flow velocity of the less viscous component, which is higher as compared to the more viscous component  18  is equalized; accordingly, at the onset of the mixing procedure, both components  17 ,  18 , can practically arrive simultaneously in the mixing region  19 . From the mixing region  19 , a flow  20  of the mixed components then will extend through the interior of the cannula holder  11  towards the cannula  12 , as is apparent from FIG.  4 . 
     Thus, in the exemplary embodiment according to FIGS. 1 to  4 , the cannula holder  11  with its inner wall defines a flow passage  21  for the mixing region  19 , which is provided on the other side, adjacent the guiding part  14 . In an alternate embodiment it would, of course, also be possible to entirely accommodate the mixing region  19  within the connecting head  1 , e.g. by providing a wall at the side of the connecting head opposite the guiding part  14  as indicated in dashed lines at  22  in FIG. 1, in which case the upper opening remaining between the guiding part  14  and this wall  22  will define an alternate exit  23 . In the embodiment according to FIG. 4, the cannula  12  de facto forms the exit. 
     In the embodiment according to FIG. 5, again a cannula holder  11  delimits the mixing region  19  or an alternate flow passage  24  for the more viscous component, respectively, cf. arrow  18 , into which the less viscous component is pressed in. Again, a connecting head  1 ′ is provided which has first and second channels  7 ,  8  for the two components. The first channel  7  for the less viscous component (thrombin) is followed by a tube  25  which is closed at its forward end  26  so that a blind tube portion  27  is provided as guiding part for the less viscous component. This blind tube portion  27  forms a dam-up portion extending from nozzle openings  28  in the tube  25  to the closed forward end  26 ; through the nozzle openings  28 , the less viscous component is pressed out after the blind tube portion  27  has been filled, cf. also the transversely extending arrows in FIG.  5 . In this manner, again the less viscous component is actively pressed with a delay, caused by filling of the blind tube portion  27 , into the flow of the more viscous component indicated by arrow  18  in the flow passage  21  within the cannula holder  11 . Otherwise, the embodiment of the mixing device according to FIG. 5 corresponds to the embodiment according to FIGS. 1 to  4 , primarily as regards the connecting part  2  of the connecting head  1 ′ for connection with first and second syringe bodies  5 ,  6 , as well as for applying the mixed components through the cannula  12 . 
     The device according to FIG. 6 is similar to that according to FIG. 5 as regards the provision of a blind tube portion  27 , yet it differs from that according to FIG. 5 in that instead of a synthetic material connecting head, first and second ducts  7 ′,  8 ′ for the two components are provided which are guided one within the other, the first duct  7 ′ merging into the blind tube portion  27 , with nozzle openings  28  being provided in the preceding region. The two ducts  7 ′,  8 ′ are slipped onto the Luer-type coni of syringe bodies  5 ,  6 , and a catheter tube  29 , e.g., is put on second duct  8 ′ which is provided for the highly viscous component. This catheter tube  29  forms the flow passage for the highly viscous component following second duct  8 ′, and in combination with the latter it also defines the mixing region  19 , where the less viscous component, after a time delay caused by filling of the blind tube portion  27 , is pressed into the flow  18  of the more viscous component through the nozzle openings  28 . 
     Also in the embodiment according to FIGS. 7 and 8, a blind tube portion  27 ′ is provided to delay the less-viscous component (cf. arrow  17 ) relative to the more viscous component  18 . In detail, in this embodiment a tube-shaped part  30 , e.g. of synthetic material, is provided which may, e.g., form an extension of a connecting head  1  or  1 ′ according to FIGS. 1 to  4  or  5 , and which inwardly is subdivided as far as to the closed end  32  of the blind tube portion  27 ′ by a separating wall  31  so as to form separate flow passages for the two components of different viscosities, cf. arrows  17  and  18 . In the separating wall  31 , again nozzle openings  28  are provided at a distance in front of the closed end  32 , through which the less viscous component  17 , after having been delayed, e.g. after filling of the blind tube portion  27 ′, is pressed out and actively pressed into the flow  18  of the more viscous liquid; the mixing region therefor again is indicated by  19 . Subsequently, the component mixture continues to flow at  20  in tube-shaped part  30 , e.g. to a cannula not illustrated in detail or to a catheter not illustrated in detail, either. 
     Further modifications for pressing the less viscous component with delay into the jet of the more viscous component are conceivable, such as particularly that such pressing in is effected directly in the interior of a collecting head; in this case it is also conceivable that the collecting head provides for a spray application of the mixture at its end side (instead of application via a cannula or a catheter). Moreover, it is also conceivable to provide the mixing space  19  directly within a cannula, e.g. by lengthening the second duct  8 ′ to a cannula in the embodiment according to FIG.  6 . 
     In a further embodiment, pressing in of the less viscous component into the more viscous component is effected in the application part itself, i.e., e.g., in a cannula or needle, in particular in such an exchangeable part. This means that within the application part itself, a means for pressing in, e.g. a deflection means, may be provided. After a single use of the device, the respective application part may simply be exchanged and replaced by a new part. 
     In a further embodiment, the device comprises at least one further channel. The latter may, e.g., be used for supplying a gas, e.g. air or CO 2 , or for cleaning the device or the application part, respectively. The device may also comprise two further channels, wherein one channel serves to supply a gas and the second channel serves for cleaning the device. By supplying a gas, in particular the components to be mixed are sprayed, e.g. directly onto the wound area to be treated. 
     For special embodiments of the device, such as e.g., that of a catheter, also a pressure regulating means may be provided for the gas supply. Cleaning of the device from contaminations or deposits that have formed, such as, e.g., clot formations which form by mixing thrombin and fibrinogen, may, e.g., be effected by simple sucking off by means of a vacuum in the additional channel. Cleaning may also be effected by other methods known from the prior art.