Adjustable vascular ring and implantable kit comprising such a ring

Abstract

Ring comprising: an outer belt (3) equipped with closing means (7) for closing the ring (1) around a duct (2); an inner chamber (4) that can be inflated and deflated; a flexible inflation/deflation tube (5);
wherein the lips have contact surfaces facing each other, the closing means comprising at least one perforation arranged on the contact surface of a first of the two lips and at least one protrusion protruding from the contact surface of a second of the two lips, the protrusion and the perforation being configured so that the protrusion is retained in the perforation by fitting, the fitting being selected to be released in the event of overpressure in the ring.

Claims

1. A ring with an adjustable inner diameter, intended to be implanted and closed around a biological duct, in order to control a diameter of the biological duct and thus a flow rate and/or pressure of a fluid circulating in the biological duct, this ring comprising: an outer belt with a constant diameter in a closed position; an inner chamber that can be inflated and deflated in the closed position, so as to vary an inner diameter thereof; a flexible inflation/deflation tube, one end of which is connected to the inner chamber and the other end of which is intended to be connected to inflation means; the outer belt and the inner chamber forming open collars, the outer belt being equipped with closing means for closing the ring around the biological duct; wherein the closing means comprise two lips capable of being joined to one another and to be separated from one another, after the ring is implanted and closed around the biological duct, by over-inflation of the inner chamber, wherein the lips have contact surfaces facing each other, the closing means comprising at least one perforation arranged on the contact surface of a first of the two lips and at least one protrusion protruding from the contact surface of a second of the two lips, the protrusion and the at least one perforation being configured so that the protrusion is retained in the at least one perforation by fitting, the fitting being selected to be released in the event of overpressure in the ring.

2. The ring according to claim 1, wherein the inner chamber, at rest and in the closed position, has a reduced inner diameter corresponding to a smallest reduced diameter required when in use for controlling the diameter of the biological duct.

3. The ring according to claim 1, wherein the at least one perforation is a through hole formed in the first lip and the protrusion is a tongue comprising a fitting portion attached to the contact surface of the second lip and sized to be retained in the through hole by friction fitting.

4. The ring according to claim 3, wherein the tongue comprises a grasping portion adjacent the fitting portion opposite the second lip, the grasping portion being sized to pass through the through hole and to be grasped by a user.

5. The ring according to claim 1, wherein the at least one perforation is a through hole formed in the first lip and the protrusion is a tongue, the tongue comprising a fitting portion attached to the contact surface of the second lip and sized to be arranged within the through hole, and an enlarged portion sized to rest on a surface of the first lip opposite a contact face of the first lip.

6. The ring according to claim 5, wherein the tongue comprises a grasping portion adjacent the fitting portion opposite the second lip, the grasping portion being sized to pass through the through hole and to be grasped by a user.

7. The ring according to claim 1, wherein the inner chamber has no invagination at rest and, in the closed position of the ring, an inner edge of the inner chamber intended to be in contact with the duct has a substantially circular shape.

8. The ring according to claim 1, wherein the inner diameter of the inner chamber decreases by inflation and increases by deflation.

9. The ring according to claim 1, wherein the lips extend in the centrifugal direction.

10. The ring according to claim 1, comprising at least one radio-opaque part.

11. The ring according to claim 1, wherein the inner chamber forms, at rest and in a non-closed position of the ring, an open collar on an angular sector less than or equal to 5° and the outer belt forms, at rest and in the non-closed position of the ring, an open collar over an angular sector less than or equal to 10°.

12. A kit that can be implanted by surgical route, allowing an adjustment of an inner diameter of a biological duct and thus a flow rate of a fluid circulating in the biological duct, the kit comprising: * a ring according to claim 1; * an inflation/deflation module intended to be connected to a distal end of the flexible inflation/deflation tube, in order to allow the in situ injection of an inflation/deflation fluid into the inner chamber or the in situ extraction of an inflation/deflation fluid out of the inner chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The following description of a preferred embodiment of the ring according to the invention, will highlight other remarkable features.

(2) This detailed description is given with reference to the attached figures in which:

(3) FIGS. 1A & 1B represent perspective views of the ring according to an embodiment, deflated and in the closed and open positions respectively.

(4) FIGS. 2A, 2B & 2C represent top views of the ring, at rest and respectively in closed (2A) and open positions according to a preferred embodiment (FIG. 2C) and according to an embodiment variant (FIG. 2C), ready to be positioned around the duct.

(5) FIG. 3 is a longitudinal cross-sectional view along the cutting plane III-III of FIG. 2A, 2B or 2C.

(6) FIGS. 4A & 4B are front views of the ring shown in FIGS. 2A & 2B or 2C respectively.

(7) FIG. 4C is a longitudinal cross-sectional view along the cutting plane IV-IV of FIG. 3,

(8) FIGS. 5a and 5b are top views of another embodiment of the ring with closing means capable of being separated from one another, after the ring is implanted and closed around a biological duct, by over-inflation of the inner chamber, lips of closing means being joined to one another by a tongue attached to one of the lips and friction fitted in a through hole of the other lip,

(9) FIG. 5c is a top view of another embodiment of the ring with closing means capable of being separated from one another, after the ring is implanted and closed around a biological duct, by over-inflation of the inner chamber, lips of closing means being joined to one another by a tongue attached to one of the lips and snap fitted in a through hole of the other lip.

(10) As shown in the attached figures the ring (1) according to the invention is a ring that can be inflated and deflated so as to vary its inner diameter (Ø.sub.i) so as to be able to compress and release the segment of biological duct for example of blood vessel such as the portal vein, around which said ring (1) is intended to be implanted and closed for controlling the flow circulating in the duct/vessel (2) represented by dot-and-dash lines in the figures.

(11) The ring (1) comprises: an outer belt (3); an inner chamber (4) that can be inflated and deflated; a flexible inflation/deflation tube (5).

(12) The outer belt (3) has a substantially constant inner diameter and outer diameter. This outer belt (3) is similar to an open collar (FIGS. 1B, 2B, 2C & 4B) the 2 free ends of which have closing means (7) comprising two outer lips (3.sub.1, 3.sub.2) extending in the centrifugal direction and having faces (3.sub.3, 3.sub.4) opposite one another in the open collar (FIGS. 1B, 2B, 2C & 4B) and in contact with one another in the closed collar (FIGS. 1A, 2A & 4A). As shown in FIGS. 2A, 2B, 2C and 3. These lips (3.sub.1, 3.sub.2) each comprise closing means described in greater details later in order to ensure the closing (FIGS. 1A, 2A & 4A) of the ring (I) after implantation around the vessel (2) the flow rate of which is to be regulated.

(13) This outer belt (3) is made of a semi-rigid material of hardness D1 and selected from the group of biocompatible elastomers, comprising or, even better, constituted by silicone elastomers or analogues.

(14) The inner chamber (4) is an inflatable and deflatable balloon having, at rest and in the closed position (FIG. 2A), a diameter (Ø.sub.ir), which may correspond to the minimum diameter value (+/−10%) desired for use, namely a diameter which restricts the diameter Dc of the duct around which it is positioned as soon as it is put in place. In the case of the human portal vein, the normal diameter or maximum value D.sub.vpn before reduction is, for example, comprised between 10 mm and 20 mm. The ring put in place and locked around the portal vein has an inner diameter Ø.sub.ir, which determines a reduction of the portal flow rate preferably by at the most 50%.

(15) Under the effect of the inflation, the inner chamber (4) increases in volume in a centripetal direction, which reduces its inner diameter Ø.sub.i. The deflation produces a reduction in the volume of the inner chamber (4), in centrifugal direction, in order to compress or release respectively the vessel (2) of a patient (e.g. portal vein), around which the ring (1) is put in place and closed using the closing means (7).

(16) In the embodiment shown in FIG. 2B, the open collar constituted by the outer belt (3) has an opening extending along a narrow channel delimited by the parallel faces 3.sub.3 and 3.sub.4 of the outer lips 3.sub.1 & 3.sub.2.

(17) In the preferred embodiment variant shown in FIG. 2C, the open collar constituted by the outer belt (3) has an opening extending over an angular sector α.sub.3 comprised between 1° and 10° and preferably equal to approximately 10° in this example. In this variant, the inner chamber (4) is an open collar the ends of which delimit an opening extending over an angular sector c comprised between 1° and 5° and preferably equal to approximately 5°.

(18) As shown by the figures, in particular FIG. 3, this inner chamber (4) is annular and comprises, in the example shown in the drawings (FIG. 3), an outer wall (4.sub.1) in contact with and/or firmly fixed to the outer belt (3) and a curved inner wall (4.sub.2), the outer wall (4.sub.1) and the inner wall (4.sub.2) being connected to one another by lateral faces that are substantially straight in the example selected, but which could be curved and are denoted by the reference numbers (4.sub.3, 4.sub.4). The inner chamber (4) could be toroid-shaped according to a variant.

(19) The inner wall (4.sub.2) forms the inner edge of this inner chamber (4). This inner edge (4.sub.2) has a circular shape, when the ring is at rest (neither inflated: no internal overpressure, nor deflated: no internal low pressure) in the closed position (FIGS. 1A, 2A & 4A), and not arranged around a duct. According to the invention, this circular shape of the inner edge (4.sub.2), and, more generally, of the inner chamber (4) is maintained once the ring is arranged around a duct (e.g. vein) and during the inflation and deflation operations. This means that the inner chamber (4) forms no invagination, fold or bulge, either in the rest state, in the inflated state, or in the deflated state. The shape of the inner edge (4.sub.2) and, more generally, of the inner chamber (4), remains “substantially” flat and circular, once the ring is arranged around a duct (e.g. vein), from the inflated rest state to a further inflated state and a deflated state corresponding to the requirements of use. In the case of adjustment of the human portal flow rate, these inflated and deflated states are included, for example, within the following inner diameter Ø.sub.i limits (in mm and in increasing order of preference): [5-25]; [6-24]; [7-20].

(20) As shown in FIGS. 2A, 2B, 2C, 3, 4C, a radio-opaque band (4′) may be inserted between the inner chamber (4) and the outer belt (3), in the outer wall (4.sub.2).

(21) The inner chamber (4) is, for example, made of a flexible material of hardness D2 and selected from the group of biocompatible flexible elastomers comprising or, even better, constituted by silicone elastomers or analogues.

(22) According to a preferred feature of the invention, the hardness D1 of the outer belt (3) is greater than the hardness D2 of the inner chamber (4). For example, D1 is comprised between 60 and 100, preferably 70-90, for example of the order of 80 Shore A. According to another preferred feature of the invention, the hardness D2 of the inner belt (4) is comprised between 5 and 40, preferably 10 and 30, and even more preferably of the order of 20 Shore A.

(23) The flexible inflation/deflation tube (5) is connected by its proximal end (5p) to the inside of the inner chamber (4) and by its distal end (5d) to inflation means not shown in FIG. 3. The inflation/deflation tube (5) is diametrically opposite the opening of the ring (1) as can be seen in FIGS. 1A, 1B, 2A, 2B, 2C, 3 and 4C. The outer belt (3) has an end piece (6) which extends towards the outside and which receives the proximal end (5p) of the inflation tube (5). This inflation tube (5) can be equipped with a plastic non-return valve.

(24) The inflation tube (5) can be made of the same material as the inner chamber (4), for example, with a hardness D3 comprised between D1 and D2, e.g. of the order of 60 Shore A.

(25) The inflation/deflation means (not shown in the drawings) are constituted for example by a syringe, preferably a screw syringe making it possible to make precise inflation/deflation adjustments by injection/tapping of the inflation/deflation fluid.

(26) The ring (1) according to the invention can be put in place around the vessel (2) by the standard surgical route (laparotomy) or by the coelioscopic route. The closing of the ring (1) is carried out by closing means (7). The ring (1) thus positioned has a reduced inner diameter (Ø.sub.ir) which restricts the vessel (2) to the smallest reduced diameter required for use (Dvpr) and thus limits the flow rate or pressure, for example blood, to a given level dependent on Ø.sub.ir. The practitioner then proceeds to adjust the flow rate and/or pressure, by inflation/deflation. In the case of hepatectomy or liver transplant, this adjustment aims to maintain an intrahepatic pressure less than or equal to 20 mm Hg, preferably 15 mm Hg. Ø.sub.i is gradually increased by deflation. D.sub.vp and with it the flow rate and/or the blood pressure in the portal vein therefore also increase(s) gradually, until D.sub.vp reaches D.sub.vpn (normal diameter or maximum diameter of the portal vein). The time taken for this rise of D.sub.vpr to D.sub.vpn is that which is necessary for hepatic parenchyma in order to recover a capacity to contain the intrahepatic pressure below 20 mm Hg, preferably below 15 mm Hg, for the pressure and/or the flow rate downstream of the ring, corresponding to a portal diameter equal to D.sub.vpn.

(27) This significantly limits the risks of SFS syndrome for the patient.

(28) The ring according to the invention, once closed by the closing means, can be reopened by over-inflation of the inner chamber, which causes the closing means to be spaced apart from each other. After opening the ring (1), the practitioner can also take advantage of the over-inflation of the ring (1), in order to keep the free ends of the ring (1) apart from each other and thus facilitate its extraction. This has the advantage of avoiding further anaesthesia and its associated risks.

(29) FIGS. 5A, 5B and 5C show embodiments of the ring according to the invention wherein the lips of the closing means are capable of being separated from one another, after the ring is implanted and closed around a biological duct, by over-inflation of the inner chamber.

(30) In the embodiment illustrated on FIGS. 5A and 5B, the closing means comprise one perforation 3.sub.5′ arranged on the face 3.sub.3, forming a contact surface, of a first 3.sub.1 of the lips and one protrusion 8 protruding from the face 3.sub.4, forming a contact surface, of a second 3.sub.2 of the lips. In particular, the perforation 3.sub.5′ is a through hole, for example of circular cross-section, formed in the first lip 3.sub.1 and the protrusion 8 is a tongue extending from the contact surface 3.sub.4 of the second lip 3.sub.2. As previously mentioned, the first 3.sub.1 and second 3.sub.2 lips are formed of deformable material, and especially elastomeric material, such as silicone. The tongue is made in one piece with the second lip 3.sub.2 so as to be elastically deformable. The tongue is for example cylindrical of circular cross-section and has a length measured perpendicularly to the second lip 3.sub.2 from which it extends. The tongue comprise a fitting portion 8a attached to the contact surface face 3.sub.4 of the second lip 3.sub.2 and sized, in terms of diameter and length, to be retained in the through hole of the first lip 3.sub.1 by friction fitting. The friction fitting resulting from the combination of sizes and material is selected to be released in the event of overpressure in the ring.

(31) The tongue is also provided with an extension adjacent the fitting portion 8a opposite the second lip 3.sub.2. The extension has a conical shape with a diameter reducing from the base adjacent the fitting portion 8a to a tip. The extension provides an extra-length able to pass through the perforation 3.sub.5′ and thereby forms a grasping portion 8b enabling the used to grasp the tongue so as to pull the fitting portion 8a within the perforation 3.sub.5′.

(32) The tongue and the through hole could have any other suitable cross section, preferably complementary to one another.

(33) The embodiment illustrated on FIG. 5C differs from that of FIGS. 5A and 5B in that the tongue 8′ comprises an enlarged portion 8a′ sized to rest on a surface of the first lip 3.sub.1 opposite the contact face of the first lip 3.sub.1 when the ring is closed, thereby providing a snap-fitting. The enlarged portion has a transverse dimension greater than that of the through hole and, in particular, a transverse dimension that is 5% to 20% greater than that of the through hole. In the illustrated embodiment, the fitting portion of the tongue 8′ attached to the contact surface of the second lip 3.sub.2 is narrower that the through hole of the first lip 3.sub.1. The fitting portion may then be arranged within in the through hole without contacting walls of the through hole. However, the fitting portion could be otherwise configured so as to provide a friction fitting with the through hole.

(34) As in the embodiment of FIGS. 5A and 5B, the tongue 8′ may comprise a grasping portion adjacent the fitting portion opposite the second lip 3.sub.2.

(35) The invention is not limited to the disclosed tongues and through holes. The closing means could comprise any other kind of protrusion and perforation configured so that the protrusion is retained in the perforation by fitting such as force fitting, friction fitting, snap fitting and others, the fitting being selected to be released in the event of overpressure in the ring.