Abstract
A fluid interface device for delivering fluid to and/or withdrawing fluid from a patient, the device comprises a peripheral base element (2) and a fluid transmission element (4) sealingly connected to the base element and forming a central portion of the device. The fluid transmission element comprises a front platelet (6) with a primary face (8) and a secondary face (10) opposed thereto, the primary face being in contact with a patient's body fluid region (12) when the device is implanted in the patient, the fluid transmission element further comprising a counterplate (14) sealingly stacked against the secondary face of the front platelet and forming a buffer volume (16) therebetween. The front platelet comprises at least one array of microchannels (18) defining a fluid passage between the buffer volume and the primary face, the microchannels having an opening of 0.2 to 10 μm. The counterplate has at least one fluid port (20; 20a, 20b) for fluid delivery to and/or fluid withdrawal from the buffer volume.
Claims
1. A fluid interface device for delivering fluid to and/or withdrawing fluid from a patient, the device comprising: a peripheral base element; a fluid transmission element sealingly connected to the peripheral base element and forming a central portion of the device, the fluid transmission element comprising a front platelet with a primary face and a secondary face opposed thereto, the primary face being in contact with a patient's body fluid region when the device is implanted in the patient, the fluid transmission element further comprising a counterplate sealingly stacked against the secondary face of the front platelet and forming a buffer volume therebetween; the front platelet comprising at least one array of microchannels defining a fluid passage between the buffer volume and the primary face, the microchannels having an opening (D.sub.i) of 0.2 to 10 μm; the fluid transmission element having at least one fluid port for fluid delivery to and/or fluid withdrawal from the buffer volume.
2. The fluid interface device according to claim 1, having at least two fluid ports.
3. The fluid interface device according to claim 2, wherein each fluid port is arranged in the counterplate.
4. The fluid interface device according to claim 1, wherein the microchannels have an opening (D.sub.i) of 0.6 to 2 μm and wherein the primary face is provided with guard elements protruding with respect to a plane defined by microchannel exits in the primary face, guard elements being formed in such manner as to define at least one transversal limitation (D.sub.tr) over each microchannel exit, the transversal limitation being larger than the microchannel opening and being in the range of 2 to 4 μm.
5. The fluid interface device according to claim 1, wherein the front platelet is made of Si and/or Si.sub.3N.sub.4, and wherein the counterplate is made of glass.
6. The fluid interface device according to claim 1, wherein the front platelet and the counterplate are joined to each other by anodic bonding.
7. The fluid interface device according to claim 1, wherein the counterplate is substantially planar and wherein the buffer volume is enclosed within a peripheral protrusion zone of the secondary face of the front platelet.
8. The fluid interface device according to claim 1, wherein the buffer volume comprises at least two separate compartments, each one being in connection with a respective microchannels array and at least one fluid port.
9. The fluid interface device according to claim 1, further comprising a spacer element preferably made of a thermoplastic polymer, the spacer element having a first spacer face that is adhesively connected to an external face of the counterplate, the spacer element comprising traversing channels connecting the first spacer face and a second spacer face, each traversing channel being arranged to form a passage between one of the counterplate's fluid ports and a corresponding channel opening at the second spacer face.
10. The fluid interface device according to claim 9, further comprising a fluid supply connector and means for releasably attaching the fluid supply connector to the spacer element, the fluid supply connector comprising connector channels each leading from a lateral entrance port to an exit port coinciding with a channel opening at the second spacer face when the fluid supply connector is attached to the spacer element.
11. The fluid interface device according to claim 10, wherein each one of said connector channels is formed as a pair of grooves in adjacent faces of mutually contacted connector parts.
12. The fluid interface device according to claim 1, wherein the fluid transmission element and the base element are sealingly connected to each other by means of a ridge structure surrounding the fluid transmission element, the ridge structure being made of a biocompatible thermoplastic formed around the fluid transmission element by injection molding.
13. The fluid interface device according to claim 12, wherein the peripheral base element is sealingly connected to the ridge structure by injection molding thereon a covering part or by ultrasonic welding.
14. The fluid interface device according to claim 12, wherein the peripheral base element is formed as a foamed pad of a thermoplastic fluoropolymer which is suitable for implantation in a patient's blood vessel wall, and wherein the injection molded ridge structure is formed as a non-foamed body of said thermoplastic fluoropolymer.
15. The fluid interface device according to claim 1, wherein the peripheral base element is formed as rigid frame structure suitable for fixation to an osseous structure of a patient.
16. The fluid interface device according to claim 9, further comprising a fluid supply connector attached to the spacer element, the fluid supply connector comprising connector channels each leading from an entrance port to an exit port coinciding with a channel opening at the second spacer face, the fluid supply connector being configured as a sealing mass that encapsulates the spacer element and the fluid transmission element and furthermore forms the peripheral base element.
17. The fluid interface device according to claim 1, which is configured as an elongated body having a proximal end, a distal end and a lateral surface therebetween, the front platelet of the fluid transmission element being disposed to form part of the lateral surface.
18. The fluid interface device according to claim 17, wherein the distal end of the elongated body has a pointed shape.
19. The fluid interface device according to claim 17, wherein the elongated body is provided with a longitudinal passage extending from the distal end to the proximal end.
20. The fluid interface device according to claim 16, wherein the peripheral base element forms an outer sheath of the elongated body.
21. The fluid interface device according to claim 17, wherein the front platelet and the counterplate are made of Si and/or Si.sub.3N.sub.4.
22. The fluid interface device according to claim 17, wherein the buffer volume comprises a single compartment being in connection with a respective microchannels array and one fluid port.
23. The fluid interface device according to claim 17, wherein the buffer volume comprises a single compartment being in connection with a respective microchannels array and two fluid ports.
24. The fluid interface device according to claim 17, wherein the buffer volume comprises two separate compartments, each compartment being in connection with a respective microchannels array and a respective fluid port.
25. The fluid interface device according to claim 17, wherein the buffer volume comprises two separate compartments, each compartment being in connection with a respective microchannels array and two fluid ports.
26. The fluid interface device according to claim 24, wherein the two separate compartments are arranged at the same side of the elongated body.
27. The fluid interface device according to claim 17, wherein the elongated body comprises for each fluid port a fluid passage leading to a channel opening at the proximal end of the elongated body.
28. The fluid interface device according to claim 27, wherein said proximal end is provided with means for attaching a fluid supply connector to each one of said corresponding channel openings.
29. The fluid interface device according to claim 1, wherein the peripheral base element is configured as a wall section of a tubular segment suitable for containing a patient's body fluid.
30. The fluid interface device according to claim 29, wherein the fluid transmission element and the base element are sealingly connected to each other by means of a ridge structure surrounding the fluid transmission element, the ridge structure being made of a biocompatible thermoplastic formed around the fluid transmission element by injection molding, and wherein the peripheral base element is integrally formed on the tubular segment which is also made of the biocompatible thermoplastic.
31. The fluid interface device according to claim 29, wherein the tubular segment is provided at both ends thereof with means for connecting to a patient's systemic circuit.
32. A system for delivering fluid to and/or withdrawing fluid from a patient's body region, the system comprising a fluid interface device according to claim 1, fluid storage means and fluid transfer means for controlled fluid delivery to and fluid withdrawal from the buffer volume via the at least one fluid port, the system being configured to be able to perform at least the following steps according to a pre-defined step sequence: a) running flushing medium through the buffer volume; b) running flushing medium through the microchannels array; c) withdrawing patient's body fluid through the microchannels array; and d) delivering a therapeutic agent to the patient.
33. The system according to claim 32, wherein the fluid transfer means are configured as transdermal tubing.
34. The system according to claim 32, wherein the fluid transfer means comprise: a subcutaneously implantable injection port having at least one injection chamber, each injection chamber having an upper inlet opening covered by a pierceable septum and an exit opening; at least one two-ended fluid transfer line connectable at one end thereof to said exit opening and connectable at the other end thereof to a corresponding fluid port of said fluid interface device.
35. The system according to claim 32, further comprising means for establishing a continuous or intermittent flow of supply medium through the buffer volume, whereby a fraction of supply medium is delivered to the patient through the fluid transmission element.
36. (canceled)
37. A method of operating the system according to claim 32, in which method a flushing medium is delivered to the buffer volume so as to maintain an overpressure relative to a base pressure in the patient's body region when the system is not withdrawing patient's body fluid or delivering a therapeutic agent to the patient, thereby preventing any flow from the patient's body region through the microchannels into the buffer volume.
38. A method for delivering fluid to and/or withdrawing fluid from a patient's body region, comprising: providing the fluid interface device of claim 1, which is optionally part of a system also comprising fluid storage means and fluid transfer means for controlled fluid delivery to and fluid withdrawal from the buffer volume via the at least one fluid port, optionally delivering a flushing medium to the buffer volume, whereby an overpressure relative to a base pressure in the patient's body region when the system is not withdrawing patient's body fluid or delivering a therapeutic agent to the patient is maintained and, thereby preventing any flow from the patient's body region through the microchannels into the buffer volume, and withdrawing the fluid/the patient's body fluid from the patient's body region through the microchannels array and/or delivering the fluid/the therapeutic agent to the patient.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The above mentioned and other features and objects of this invention and the manner of achieving them will become more apparent and this invention itself will be better understood by reference to the following description of various embodiments of this invention taken in conjunction with the accompanying drawings, wherein:
[0069] FIG. 1 shows a first embodiment of a fluid interface device, in a sectional view;
[0070] FIG. 2 shows a part of the fluid interface device of FIG. 1 with an attached spacer element, in a sectional view;
[0071] FIG. 3 shows a second embodiment of a fluid interface device, in a schematic sectional view;
[0072] FIG. 4 shows a front platelet of a third embodiment, in a plan view seen from the secondary face;
[0073] FIG. 5 shows the front platelet of FIG. 4 in a perspective view;
[0074] FIG. 6 shows the front platelet of FIG. 4 in a sectional view according to section F-F;
[0075] FIG. 7 shows an enlarged portion G of FIG. 6;
[0076] FIG. 8 shows the front platelet of FIG. 4 with a counterplate attached thereto, in a plan view seen from the secondary face;
[0077] FIG. 9 shows the front platelet and counterplate of FIG. 8 in a sectional view according to section B-B;
[0078] FIG. 10 shows the front platelet and counterplate of FIG. 8 in a sectional view according to section A-A;
[0079] FIG. 11 shows the front platelet and counterplate of FIG. 8 in a perspective view;
[0080] FIG. 12 shows a fluid interface device including the front platelet and counterplate of FIG. 8 and a fluid supply connector attached thereto, in a plan view seen from the primary face;
[0081] FIG. 13 shows the arrangement of FIG. 12 in a sectional view according to section A-A;
[0082] FIG. 14 shows the arrangement of FIG. 12 in a sectional view according to section B-B;
[0083] FIG. 15 shows the arrangement of FIG. 12 in a perspective view;
[0084] FIG. 16 shows the arrangement of FIG. 12 in a plan view seen from the secondary face;
[0085] FIG. 17 shows the arrangement of FIG. 16 in a sectional view according to section C-C;
[0086] FIG. 18 shows the arrangement of FIG. 16 in a sectional view according to section D-D;
[0087] FIG. 19 shows another fluid interface device including the front platelet and counterplate of FIG. 8 and a fluid supply connector attached thereto, in a plan view seen from the side opposite to the primary face;
[0088] FIG. 20 shows the arrangement of FIG. 19 in a sectional view according to section A-A;
[0089] FIG. 21 shows the arrangement of FIG. 19 in a sectional view according to section B-B;
[0090] FIG. 22 shows the arrangement of FIG. 19 in a perspective view;
[0091] FIG. 23 shows a basic part of a further fluid interface device, in a sectional view;
[0092] FIG. 24 shows a fourth embodiment of a fluid interface, in a schematic perspective view;
[0093] FIG. 25 shows an enlarged view of a detail of FIG. 24;
[0094] FIG. 26 shows the fluid interface device of FIG. 24 in a plan view seen from the secondary face;
[0095] FIG. 27 shows the fluid interface device of FIG. 24 in a side elevation view;
[0096] FIG. 28 shows the the fluid interface device of FIG. 24 in a sectional view according to section A-A;
[0097] FIG. 29 shows the the fluid interface device of FIG. 24 in a sectional view according to section B-B;
[0098] FIG. 30 shows an enlarged view of detail C of FIG. 28;
[0099] FIG. 31 shows an enlarged view of detail D of FIG. 28;
[0100] FIG. 32 shows a fifth embodiment of a fluid interface, in a partially cut away perspective view;
[0101] FIG. 33 shows an enlarged view of a detail of FIG. 32;
[0102] FIG. 34 shows the fluid interface device of FIG. 32 in a plan view seen from the secondary faces;
[0103] FIG. 35 shows the fluid interface device of FIG. 32 in a plan view seen from the primary face, with some longitudinal segments cut away;
[0104] FIG. 36 shows the fluid interface device of FIG. 32 in a side elevation view, with some longitudinal segments cut away;
[0105] FIG. 37 shows the fluid interface device of FIG. 32 in an axial view from the proximal end;
[0106] FIG. 38 shows the the fluid interface device of FIG. 32 in a sectional view according to section A-A;
[0107] FIG. 39 shows the the fluid interface device of FIG. 32 in a sectional view according to section B-B;
[0108] FIG. 40 shows an enlarged view of detail C of FIG. 38;
[0109] FIG. 41 shows an enlarged view of detail D of FIG. 38;
[0110] FIG. 42 shows a sixth embodiment of a fluid interface device, in a schematic sectional view;
[0111] FIG. 43 shows the arrangement of FIG. 16 in a sectional view according to section C-C;
[0112] FIG. 44 shows the arrangement of FIG. 16 in a sectional view according to section D-D;
[0113] FIG. 45 shows another fluid interface device with an integrally formed tubular section, including the front platelet and counterplate of FIG. 8 and a fluid supply connector attached thereto, in a side elevation view;
[0114] FIG. 46 shows the arrangement of FIG. 45 in a plan view;
[0115] FIG. 47 shows the arrangement of FIG. 45 in a sectional view according to section A-A;
[0116] FIG. 48 shows the arrangement of FIG. 45 in a perspective view;
[0117] FIG. 49 shows a more detailed rendition of FIG. 47;
[0118] FIG. 50 shows an enlarged view of the portion marked as “B” in FIG. 49; and
[0119] FIG. 51 shows a vertical section through a front platelet provided with guard elements, partially cut away.
DETAILED DESCRIPTION OF THE INVENTION
[0120] In order to better explain the general principle of the present invention, FIGS. 1 and 2 show a basic embodiment of a fluid interface device, in a schematic representation and not to scale. The device comprises a peripheral base element 2, which in the example shown is configured as a simple surrounding piece with an outwardly protruding flange 3. A composite part generally denoted as fluid transmission element 4 is sealingly connected to the base element 2 and forms a central portion of the device. The base element 2 is generally intended to provide some kind of attachment or fixture to a patient's body part and could be integrally formed with the fluid transmission element. The latter comprises a front platelet 6 with a primary face 8 and with a secondary face 10 opposed thereto. The primary face is in contact with a patient's body fluid region generally denoted as 12 when the device is implanted in the patient. The fluid transmission element further comprises a counterplate 14 that is sealingly stacked against the secondary face of the front platelet and forms a buffer volume 16 therebetween. Importantly, the front platelet 6 comprises at least one array of microchannels 18 defining a fluid passage between the buffer volume and the primary face. Depending on the intended use of the device, the microchannels are formed with an opening of 0.2 to 10 μm. The counterplate has two fluid ports 20a; 20b for fluid delivery to and/or fluid withdrawal from the buffer volume.
[0121] In the example shown, the counterplate 10 is substantially planar and is made of glass. In contrast, the front platelet 6 has a peripheral protrusion zone 22 directed towards the counterplate 10 and forming a lateral wall enclosing the buffer volume 16. The front platelet 6 is made of Si and/or Si.sub.3N.sub.4 and is joined to the counterplate 14 by anodic bonding.
[0122] FIG. 2. shows the fluid interface device of FIG. 1, but without peripheral base element 2. A spacer element 24 made of a thermoplastic polymer has a first spacer face 26 that is connected to an external face of the counterplate 14 by means of a suitable adhesive. The spacer element 24 comprises traversing channels 28a; 28b connecting the first spacer face and a second spacer face 30 opposed therefrom. Each traversing channel is arranged to form a passage between one of the counterplate's fluid ports 20a, 20b and a corresponding channel opening 32a 32b at the second spacer face. As will be seen from forthcoming examples, the spacer element 24 is a useful means for coupling with an appropriately configured tubing connector for supply and delivery of fluid from and to an external device.
[0123] The basic structure of a fluid interface device suitable for implantation in a venous wall is further illustrated in FIG. 3. For this purpose the peripheral base element 2 is formed as a foamy pad of a thermoplastic fluoropolymer which is suitable for implantation in a patient's blood vessel wall. Such a materials are commercially available, e.g. as GORE® ACUSEAL Cardiovascular Patch. In order to form a compact, reliable and medium tight connection between the foamy pad 2 and the fluid interface structure 4, an arrangement as shown in FIG. 3 can be used. Such arrangement comprises a ridge structure 34 surrounding the fluid transmission element 4 and sealingly connecting the latter with the base element 2. The ridge structure 34 is made of a biocompatible thermoplastic fluoropolymer formed around the fluid transmission element 4 by injection molding. In order to promote a good adhesion of the ridge structure 34 with the fluid transmission element 4, the front platelet 6 has an outwardly protruding collar 36 provided with a plurality of holes 38. As shown in FIG. 3, the injection molded material of the ridge structure 34 is disposed around the collar 36 and within the holes 38, which provides a form-locking effect. It will be understood that instead of holes the collar could be provided with other types of locking structures such as recesses and protrusions.
[0124] In the example shown in FIG. 3, a covering part 40, which is generally ring-like and made of the same thermoplastic fluoropolymer as the ridge structure 34 surrounds the spacer element 24 and is in contact with the ridge structure 34. The ridge structure 34 and the covering part 40 surround a portion of the peripheral base element 2 in a C-type manner. The C-shaped boundary zone between the peripheral base element 2, the ridge structure 34 and the covering part 40 is connected by ultrasonic welding. It will be understood that this convenient joining method requires that the thermoplastic fluoropolymer of the ridge structure and of the covering part is either the same as or is compatible with the fluoropolymer forming the foamy pad peripheral base element 2. In the example shown, the covering part 40 is formed with an overlap zone 42 extending over the second face 30 of the spacer element 24.
[0125] As also shown in the schematic representation of FIG. 3, the front platelet 6 and the counterplate 14 are joined to each other in a first contacting zone 44 formed by anodic bonding.
[0126] Further, the counterplate 14 and the spacer 24 are joined to each other in a second contacting zone 46 by means of a suitable adhesive.
[0127] A convenient manner of assembling the exemplary device of FIG. 3 may be summarized as follows: [0128] place a previously assembled fluid transmission element 4 onto a corresponding holder with the front platelet 6 downwards [0129] form the peripheral ridge 34 by injection molding around the fluid transmission element 4 [0130] stack the spacer element 24 onto the counterplate 14 and join with suitable adhesive [0131] place a suitably formed peripheral base element 2 made of foamy thermoplastic fluoropolymer on top of the peripheral ridge 34 [0132] separately form the cover part 40 and stack the same on top of the peripheral ridge 34 and spacer element 24 [0133] connect the cover part 40, the peripheral ridge 34 and the peripheral base element 2 sandwiched therebetween by means of ultrasonic welding.
[0134] Further details of an embodiment of the fluid interface device suitable for implantation in a blood vessel are illustrated in FIGS. 4 to 18. Features corresponding to those in the embodiments explained above are generally denoted with the same reference numerals as above.
[0135] As will be seen from FIGS. 4 to 7, the microchannels 18 are positioned in elongated grooves 50 formed in the front platelet 6. The grooves 50 constitute a part of the front platelet having minimal thickness so as to allow formation of the narrow microchannels 18. Also shown in FIGS. 4 to 7 are the holes 38 formed in the collar zone 36. A thicker platelet zone 52 located between a pair of grooves 50 serves as mechanical reinforcement.
[0136] As evident from FIGS. 8 to 11, a counterplate 14 stacked on the secondary side of the front platelet 6 leaves free the collar zone 36. In the example shown there are two separate buffer volumes 16a and 16b, each of which is provided with a pair of fluid ports 20a, 20b or 20c, 20d, respectively.
[0137] FIGS. 12 to 18 show a fluid interface with a fluid supply connector 54 attached thereto. In particular, FIG. 13 shows connector channels 56 each leading from a lateral entrance port 58 to an exit port 60 coinciding with a channel opening 32 at the second spacer face 30. As shown in FIGS. 15, 16 and 18, the arrangement has four hook-like elements 62 for releasably attaching the fluid supply connector 54 to the spacer element 24. In the example shown, the hook-like elements 62 traverse suitable openings 64 provided in the covering part 40 placed on top and around spacer 24. The arrangement shown in these figures comprises two separate compartments each comprising a buffer volume, a fluid transmission element and two fluid ports.
[0138] As illustrated in FIGS. 17 and 18, the ridge structure 34 and the peripheral base element 2 are formed having a concave cross section dimensioned in accordance with the cross section of a blood vessel into which the entire device can be implanted.
[0139] FIG. 18 furthermore shows an advantageous manner of sealingly connecting the peripheral base element 2 and the ridge structure 34 by injection molding thereon thereon the covering part 40, whereby a medium-tight closure is formed between parts 40 and 34 and also with part 2 inserted therebetween.
[0140] A further embodiment suitable for subcutaneous or intramuscular placement is shown in FIGS. 19 to 22. A fluid transmission element generally denoted as 4 is provided with a spacer element 24 in the manner as described further above. Connector channels 56 are provided to form a fluid connection between entrance ports 58 and corresponding spacer channel openings 32. The fluid supply connector (54) is configured as a sealing mass which forms an encapsulation of the spacer element 24 and at the same time forms the peripheral base element 2.
[0141] A further variant of the fluid interface device of the present invention is illustrated in FIG. 23. The device comprises a peripheral base element 2, which in the example shown is configured as a simple surrounding piece with an inwardly protruding flange 3. The counterplate has just one fluid port 20 for fluid delivery to and/or fluid withdrawal from the buffer volume.
[0142] In the example shown, the counterplate 10 is substantially planar. In contrast, the front platelet 6 has a peripheral protrusion zone 22 directed towards the counterplate 10 and forming a lateral wall enclosing the buffer volume 16. Both the front platelet 6 and the counterplate 14 are made of Si and/or Si.sub.3N.sub.4 and are joined to each other e.g. by anodic bonding.
[0143] A third embodiment of a fluid interface device is shown in FIGS. 24 to 31. The device is configured as an elongated body having a proximal end P, a distal end D and a lateral surface S therebetween. The front platelet 6 of the fluid transmission element 4 is disposed to form part of the lateral surface S. The distal end D of the elongated body B has a pointed shape. The embodiment of FIGS. 24 to 31 is a device wherein the buffer volume 16 comprises a single compartment being in connection with a respective microchannels array 18 and one fluid port 20. As will be seen from the figures, the fluid port 20 is arranged at the proximal side of the counterplate 10 and enters into the buffer volume 16 in a substantially longitudinal direction. This allows for a very compact construction with a small overall diameter of only about 5 mm. The front platelet 6 and the counterplate 10 are form a two-plate stack that is surrounded from the peripheral base element 2, which as seen particularly from FIG. 27, forms an outer sheath of the elongated body.
[0144] The elongated body comprises a fluid passage 102 leading from the fluid port 20 to a channel opening 104 at the proximal end of the elongated body. The proximal end is provided with means 106 for attaching a fluid supply connector to the channel opening.
[0145] FIGS. 32 to 41 show a fourth embodiment of the fluid interface device wherein the buffer volume comprises two separate compartments 16a and 16b, each compartment being in connection with a respective microchannels array 18a, 18b and a respective fluid port 20a, 20b. The two compartments are arranged at the same side of the elongated body B. As shown in the figures, this arrangement requires that the fluid passage 102a leading from the more distal compartment 16a to the channel opening 104a passes in a laterally displaced manner along the more proximal compartment 16b.
[0146] In the embodiment shown in FIGS. 32 to 41, the elongated body B is provided with a longitudinal passage 108 extending from the distal end D to the proximal end E. The passage is configured as a smooth channel without sharp bends and has a diameter of typically 0.5 mm suitable for accommodating a guide wire as generally used in catheter type interventions.
[0147] The basic structure of a fluid interface device suitable for implantation in a tubular structure such as an arteriovenous shunt is illustrated in FIG. 42. For this purpose the peripheral base element 2 is formed as a wall section of a tubular segment to be described in more detail further below. In order to form a compact, reliable and medium tight connection between the base element 2 and the fluid interface structure 4, an arrangement as shown in FIG. 42 can be used. Such arrangement comprises a ridge structure 34 surrounding the fluid transmission element 4 and sealingly connecting the latter with the base element 2. The ridge structure 34 is made of a biocompatible thermoplastic polymer formed around the fluid transmission element 4 by injection molding. In order to promote a good adhesion of the ridge structure 34 with the fluid transmission element 4, the front platelet 6 has an outwardly protruding collar 36 provided with a plurality of holes 38. As shown in FIG. 42, the injection molded material of the ridge structure 34 is disposed around the collar 36 and within the holes 38, which provides a form-locking effect. It will be understood that instead of holes the collar could be provided with other types of locking structures such as recesses and protrusions.
[0148] In the example shown in FIG. 42 the peripheral base element 2 is sealingly connected to the ridge structure 34 by a suitable joining method such as ultrasonic welding. It will be understood that this convenient joining method requires that the thermoplastic polymer of the ridge structure 34 and that of the peripheral base element 2 are either the same or compatible to each other.
[0149] However, in other embodiments the ridge structure 34 and the peripheral base element 2 are integrally formed of one and the same thermoplastic polymer.
[0150] As also shown in the schematic representation of FIG. 42, the front platelet 6 and the counterplate 14 are joined to each other in a first contacting zone 44 formed by anodic bonding. Further, the counterplate 14 and the spacer 24 are joined to each other in a second contacting zone 46 by means of a suitable adhesive.
[0151] A convenient manner of assembling the exemplary device of FIG. 42 for the case that the ridge structure 34 and the peripheral base element 2 are integrally formed may be summarized as follows: [0152] place a previously assembled fluid transmission element 4 onto a corresponding holder with the front platelet 6 downwards [0153] stack the spacer element 24 onto the counterplate 14 and join with suitable adhesive 46 [0154] form the ridge structure 34 and peripheral base element 2 by injection molding around the fluid transmission element 4.
[0155] Further details of an embodiment of the fluid interface device suitable for implantation in a blood vessel are illustrated in FIGS. 4 to 16, and in FIGS. 43 and 44. Features corresponding to those in the embodiments explained above are generally denoted with the same reference numerals as above.
[0156] FIGS. 12 to 16 and 43 and 44 show a fluid interface with a fluid supply connector 54 attached thereto. It should be noted particularly in relation to FIGS. 14 and 15 and also FIGS. 43 and 44 that the peripheral base element 2 could also be integrally formed with an entire tubular section of the device. In that case the feature denoted as 2 in the lower part of FIGS. 17 and 18 would actually continue downwards to form a substantially circular closed section.
[0157] As illustrated in FIGS. 43 and 44, the ridge structure 34 and the peripheral base element 2 are formed having a concave cross section dimensioned in accordance with the cross section of a blood vessel into which the entire device can be implanted.
[0158] Comparison of FIG. 44 with FIG. 18 furthermore shows that the peripheral base element 2, the ridge structure 34 and also the covering part 40 which in the embodiment of FIG. 18 is a separate component, are integrally formed in the embodiment of FIG. 44.
[0159] A further embodiment particularly suitable for connection to a tubular structure such as an arteriovenous shunt is shown in FIGS. 45 to 50. The arrangement generally comprises a peripheral base element 2 circumferentially surrounding a fluid transmission element 4 consisting of a front platelet 6 with a primary face 8 and a secondary face 10 opposed thereto, the primary face being in contact with a patient's body fluid region 12 when the device is implanted in the patient. The fluid transmission element further comprises a counterplate 14 sealingly stacked against the secondary face of the front platelet and forming a buffer volume 16 therebetween. The front platelet comprises an array of microchannels 18 defining a fluid passage between the buffer volume and the primary face. The peripheral base element is configured as a wall section of an integrally formed tubular segment 202 which comprises an integrally formed ridge structure 204 providing a sealing lateral closure of the layered fluid transmission element 4.
[0160] The tubular segment 202 is provided at both ends thereof with connecting means 206 for medium tight coupling to correspondingly equipped ends 208 of a tubular structure 210 such as an arteriovenous shunt grafted to a patient. In the example shown the connecting means are configured as end sections of the tubular segment 202 provided with ratchet-like external projections 206 and with a terminal collar 212 for receiving an O-ring 214. As will also be seen from the figures, the ends 208 of the grafted tubular structure 210 are provided with a crimped on ferrule 216 which has an axially forward projecting ring bracket 218 cooperating with the connectors 206 and having a front surface serving to sealingly abut against O-ring 214. In the example shown, the connection can be released by applying a radially outward force on the ring bracket 218.
[0161] FIG. 51 shows a vertical section through a front platelet 6 provided with guard elements 220. As seen from this schematic rendering, two microchannels 18 a fluid communication path between the primary face 8 and the secondary face 10. The channels have an opening with an inner diameter d.sub.i, which is selected in the range of 0.6 to 2 μm. The guard elements are formed in such manner as to define a transversal limitation D.sub.tr over each microchannel exit, the transversal limitation being larger than the microchannel opening and being selected in the range of 2 to 4 μm. The guard elements can be configured as pillars, i.e. as stub-like protrusions with an outer diameter d.sub.o or as mutually parallel ribbons with a width d.sub.o and a length that can extend across the entire primary face. As seen from the figure, the transversal limitation D.sub.tr defined by the guard elements forms a stop for a thrombocyte TH while still allowing fluid to flow through the cavity formed between the thrombocyte and the primary face 8.
