Patent ID: 12214157

DETAILED DESCRIPTION OF THE INVENTION

In order to better explain the general principle of the present invention,FIGS.1and2show a basic embodiment of a fluid interface device, in a schematic representation and not to scale. The device comprises a peripheral base element2, which in the example shown is configured as a simple surrounding piece with an outwardly protruding flange3. A composite part generally denoted as fluid transmission element4is sealingly connected to the base element2and forms a central portion of the device. The base element2is 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 platelet6with a primary face8and with a secondary face10opposed thereto. The primary face is in contact with a patient's body fluid region generally denoted as12when the device is implanted in the patient. The fluid transmission element further comprises a counterplate14that is sealingly stacked against the secondary face of the front platelet and forms a buffer volume16therebetween. Importantly, the front platelet6comprises at least one array of microchannels18defining 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 ports20a;20bfor fluid delivery to and/or fluid withdrawal from the buffer volume.

In the example shown, the counterplate10is substantially planar and is made of glass. In contrast, the front platelet6has a peripheral protrusion zone22directed towards the counterplate10and forming a lateral wall enclosing the buffer volume16. The front platelet6is made of Si and/or Si3N4and is joined to the counterplate14by anodic bonding.

FIG.2. shows the fluid interface device ofFIG.1, but without peripheral base element2. A spacer element24made of a thermoplastic polymer has a first spacer face26that is connected to an external face of the counterplate14by means of a suitable adhesive. The spacer element24comprises traversing channels28a;28bconnecting the first spacer face and a second spacer face30opposed therefrom. Each traversing channel is arranged to form a passage between one of the counterplate's fluid ports20a,20band a corresponding channel opening32a32bat the second spacer face. As will be seen from forthcoming examples, the spacer element24is a useful means for coupling with an appropriately configured tubing connector for supply and delivery of fluid from and to an external device.

The basic structure of a fluid interface device suitable for implantation in a venous wall is further illustrated inFIG.3. For this purpose the peripheral base element2is 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 pad2and the fluid interface structure4, an arrangement as shown inFIG.3can be used. Such arrangement comprises a ridge structure34surrounding the fluid transmission element4and sealingly connecting the latter with the base element2. The ridge structure34is made of a biocompatible thermoplastic fluoropolymer formed around the fluid transmission element4by injection molding. In order to promote a good adhesion of the ridge structure34with the fluid transmission element4, the front platelet6has an outwardly protruding collar36provided with a plurality of holes38. As shown inFIG.3, the injection molded material of the ridge structure34is disposed around the collar36and within the holes38, 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.

In the example shown inFIG.3, a covering part40, which is generally ring-like and made of the same thermoplastic fluoropolymer as the ridge structure34surrounds the spacer element24and is in contact with the ridge structure34. The ridge structure34and the covering part40surround a portion of the peripheral base element2in a C-type manner. The C-shaped boundary zone between the peripheral base element2, the ridge structure34and the covering part40is 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 element2. In the example shown, the covering part40is formed with an overlap zone42extending over the second face30of the spacer element24.

As also shown in the schematic representation ofFIG.3, the front platelet6and the counterplate14are joined to each other in a first contacting zone44formed by anodic bonding.

Further, the counterplate14and the spacer24are joined to each other in a second contacting zone46by means of a suitable adhesive.

A convenient manner of assembling the exemplary device ofFIG.3may be summarized as follows:place a previously assembled fluid transmission element4onto a corresponding holder with the front platelet6downwardsform the peripheral ridge34by injection molding around the fluid transmission element4stack the spacer element24onto the counterplate14and join with suitable adhesiveplace a suitably formed peripheral base element2made of foamy thermoplastic fluoropolymer on top of the peripheral ridge34separately form the cover part40and stack the same on top of the peripheral ridge34and spacer element24connect the cover part40, the peripheral ridge34and the peripheral base element2sandwiched therebetween by means of ultrasonic welding.

Further details of an embodiment of the fluid interface device suitable for implantation in a blood vessel are illustrated inFIGS.4to18. Features corresponding to those in the embodiments explained above are generally denoted with the same reference numerals as above.

As will be seen fromFIGS.4to7, the microchannels18are positioned in elongated grooves50formed in the front platelet6. The grooves50constitute a part of the front platelet having minimal thickness so as to allow formation of the narrow microchannels18. Also shown inFIGS.4to7are the holes38formed in the collar zone36. A thicker platelet zone52located between a pair of grooves50serves as mechanical reinforcement.

As evident fromFIGS.8to11, a counterplate14stacked on the secondary side of the front platelet6leaves free the collar zone36. In the example shown there are two separate buffer volumes16aand16b, each of which is provided with a pair of fluid ports20a,20bor20c,20d, respectively.

FIGS.12to18show a fluid interface with a fluid supply connector54attached thereto. In particular,FIG.13shows connector channels56each leading from a lateral entrance port58to an exit port60coinciding with a channel opening32at the second spacer face30. As shown inFIGS.15,16and18, the arrangement has four hook-like elements62for releasably attaching the fluid supply connector54to the spacer element24. In the example shown, the hook-like elements62traverse suitable openings64provided in the covering part40placed on top and around spacer24. The arrangement shown in these figures comprises two separate compartments each comprising a buffer volume, a fluid transmission element and two fluid ports.

As illustrated inFIGS.17and18, the ridge structure34and the peripheral base element2are 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.

FIG.18furthermore shows an advantageous manner of sealingly connecting the peripheral base element2and the ridge structure34by injection molding thereon thereon the covering part40, whereby a medium-tight closure is formed between parts40and34and also with part2inserted therebetween.

A further embodiment suitable for subcutaneous or intramuscular placement is shown inFIGS.19to22. A fluid transmission element generally denoted as4is provided with a spacer element24in the manner as described further above. Connector channels56are provided to form a fluid connection between entrance ports58and corresponding spacer channel openings32. The fluid supply connector (54) is configured as a sealing mass which forms an encapsulation of the spacer element24and at the same time forms the peripheral base element2.

A further variant of the fluid interface device of the present invention is illustrated inFIG.23. The device comprises a peripheral base element2, which in the example shown is configured as a simple surrounding piece with an inwardly protruding flange3. The counterplate has just one fluid port20for fluid delivery to and/or fluid withdrawal from the buffer volume.

In the example shown, the counterplate10is substantially planar. In contrast, the front platelet6has a peripheral protrusion zone22directed towards the counterplate10and forming a lateral wall enclosing the buffer volume16. Both the front platelet6and the counterplate14are made of Si and/or Si3N4and are joined to each other e.g. by anodic bonding.

A third embodiment of a fluid interface device is shown inFIGS.24to31. 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 platelet6of the fluid transmission element4is disposed to form part of the lateral surface S. The distal end D of the elongated body B has a pointed shape. The embodiment ofFIGS.24to31is a device wherein the buffer volume16comprises a single compartment being in connection with a respective microchannels array18and one fluid port20. As will be seen from the figures, the fluid port20is arranged at the proximal side of the counterplate10and enters into the buffer volume16in a substantially longitudinal direction. This allows for a very compact construction with a small overall diameter of only about 5 mm. The front platelet6and the counterplate10are form a two-plate stack that is surrounded from the peripheral base element2, which as seen particularly fromFIG.27, forms an outer sheath of the elongated body.

The elongated body comprises a fluid passage102leading from the fluid port20to a channel opening104at the proximal end of the elongated body. The proximal end is provided with means106for attaching a fluid supply connector to the channel opening.

FIGS.32to41show a fourth embodiment of the fluid interface device wherein the buffer volume comprises two separate compartments16aand16b, each compartment being in connection with a respective microchannels array18a,18band a respective fluid port20a,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 passage102aleading from the more distal compartment16ato the channel opening104apasses in a laterally displaced manner along the more proximal compartment16b.

In the embodiment shown inFIGS.32to41, the elongated body B is provided with a longitudinal passage108extending 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.

The basic structure of a fluid interface device suitable for implantation in a tubular structure such as an arteriovenous shunt is illustrated inFIG.42. For this purpose the peripheral base element2is 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 element2and the fluid interface structure4, an arrangement as shown inFIG.42can be used. Such arrangement comprises a ridge structure34surrounding the fluid transmission element4and sealingly connecting the latter with the base element2. The ridge structure34is made of a biocompatible thermoplastic polymer formed around the fluid transmission element4by injection molding. In order to promote a good adhesion of the ridge structure34with the fluid transmission element4, the front platelet6has an outwardly protruding collar36provided with a plurality of holes38. As shown inFIG.42, the injection molded material of the ridge structure34is disposed around the collar36and within the holes38, 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.

In the example shown inFIG.42the peripheral base element2is sealingly connected to the ridge structure34by 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 structure34and that of the peripheral base element2are either the same or compatible to each other.

However, in other embodiments the ridge structure34and the peripheral base element2are integrally formed of one and the same thermoplastic polymer.

As also shown in the schematic representation ofFIG.42, the front platelet6and the counterplate14are joined to each other in a first contacting zone44formed by anodic bonding. Further, the counterplate14and the spacer24are joined to each other in a second contacting zone46by means of a suitable adhesive.

A convenient manner of assembling the exemplary device ofFIG.42for the case that the ridge structure34and the peripheral base element2are integrally formed may be summarized as follows:place a previously assembled fluid transmission element4onto a corresponding holder with the front platelet6downwardsstack the spacer element24onto the counterplate14and join with suitable adhesive46form the ridge structure34and peripheral base element2by injection molding around the fluid transmission element4.

Further details of an embodiment of the fluid interface device suitable for implantation in a blood vessel are illustrated inFIGS.4to16, and inFIGS.43and44. Features corresponding to those in the embodiments explained above are generally denoted with the same reference numerals as above.

FIGS.12to16and43and44show a fluid interface with a fluid supply connector54attached thereto. It should be noted particularly in relation toFIGS.14and15and alsoFIGS.43and44that the peripheral base element2could also be integrally formed with an entire tubular section of the device. In that case the feature denoted as2in the lower part ofFIGS.17and18would actually continue downwards to form a substantially circular closed section.

As illustrated inFIGS.43and44, the ridge structure34and the peripheral base element2are 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.

Comparison ofFIG.44withFIG.18furthermore shows that the peripheral base element2, the ridge structure34and also the covering part40which in the embodiment ofFIG.18is a separate component, are integrally formed in the embodiment ofFIG.44.

A further embodiment particularly suitable for connection to a tubular structure such as an arteriovenous shunt is shown inFIGS.45to50. The arrangement generally comprises a peripheral base element2circumferentially surrounding a fluid transmission element4consisting of a front platelet6with a primary face8and a secondary face10opposed thereto, the primary face being in contact with a patient's body fluid region12when the device is implanted in the patient. The fluid transmission element further comprises a counterplate14sealingly stacked against the secondary face of the front platelet and forming a buffer volume16therebetween. The front platelet comprises an array of microchannels18defining 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 segment202which comprises an integrally formed ridge structure204providing a sealing lateral closure of the layered fluid transmission element4.

The tubular segment202is provided at both ends thereof with connecting means206for medium tight coupling to correspondingly equipped ends208of a tubular structure210such as an arteriovenous shunt grafted to a patient. In the example shown the connecting means are configured as end sections of the tubular segment202provided with ratchet-like external projections206and with a terminal collar212for receiving an O-ring214. As will also be seen from the figures, the ends208of the grafted tubular structure210are provided with a crimped on ferrule216which has an axially forward projecting ring bracket218cooperating with the connectors206and having a front surface serving to sealingly abut against O-ring214. In the example shown, the connection can be released by applying a radially outward force on the ring bracket218.

FIG.51shows a vertical section through a front platelet6provided with guard elements220. As seen from this schematic rendering, two microchannels18a fluid communication path between the primary face8and the secondary face10. The channels have an opening with an inner diameter di, 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 Dtrover 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 door as mutually parallel ribbons with a width doand a length that can extend across the entire primary face. As seen from the figure, the transversal limitation Dtrdefined 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 face8.