WO1991007918A1

WO1991007918A1 - Implantable occluder

Info

Publication number: WO1991007918A1
Application number: PCT/EP1990/002062
Authority: WO
Inventors: Zeljko MILOS^²EVIC^´; Renate MILOS^²EVIC^´; Helmut Witzigmann
Original assignee: Milos Evic Zeljko
Priority date: 1989-12-01
Filing date: 1990-11-30
Publication date: 1991-06-13
Also published as: DE3939840A1

Abstract

The implantable occluder is designed for the temporary closure of arteries, especially the hepatic artery, for temporary liver de-arterialisation. It comprises a diaphragm securable to the artery which limits a chamber (2) and can be deformed by the supply of pressurised fluid via a catheter (9) connected to the chamber (2) with the aim of reducing the cross-section of the artery to zero by exerting pressure. A particularly delicate application defined in relation to the pressure can be obtained by making the deformable diaphragm as the inner limiting wall of a chamber (2) forming a hollow cylindrical body (1); in addition, the body is fitted with an axis-parallel separating slit (8) facilitating its application to the artery. Moreover there is, when the chamber (2) is under pressure, a virtually unexpandable but flexible limiting wall connected to the inner limiting wall along the separating slit (8) and closing the chamber (2) in the region of the frontal edges of the body. After the application of the body to the artery, the edges of the separating slit may be joined together.

Description

Implantable oecluder

The invention relates to an implantable ocluder for the temporary occlusion of arteries, in particular the hepatic artery for the purpose of temporary hepatic desarterialization, with a membrane which can be fixed to the artery and delimits a chamber, and can be deformed by supplying pressure fluid via a catheter connected to the chamber and serves to reduce the arterial cross-section to zero when pressurized.

In addition to the medicinal treatment of the colonization of cancerous tumors in organs, preferably in the liver, oecluder of the aforementioned type can be found in the fight against the

REPLACEMENT LEAF Use of metastases, especially if it involves extensive colonization of colon cancer or carcinoid of the gastrointestinal tract, which can no longer be removed by surgery. With the help of such an occluder, the blood supply via the artery (arteria hepatis) and thus the supply of nutrients and oxygen to the liver deposits of malignant tumors can be prevented, with the result that there is necrosis of the tumor tissue. This interruption of the arteries is therefore not associated with an impairment of the healthy liver tissue, because the latter is normally supplied in equal parts via the artery and the portal vein (vena portae), in contrast to the tumor tissue, the supply of which is over 90% via the artery he follows.

In the known oecluder mentioned, the membrane which can be expanded by applying pressure is formed by a small balloon. This is firmly fixed on one side of a cuff formed by a silicone band, which is placed around the artery in this way and is firmly connected to the latter by sewing the ends of the silicone band by means of a non-absorbable thread, so that the balloon comes to rest on one side of the artery. The balloon is connected to the chamber of a so-called port, which is implanted in the subcutaneous tissue of the patient, via a catheter and can be punctured by puncturing a silicone membrane delimiting the port chamber with a sterile saline solution until the artery is completely occluded with a corresponding seal Expansion filled and emptied again.

This known ocluder is associated with the essential disadvantage that when the balloon is filled up, due to the production-related, unavoidable differences in wall thickness, there is an uneven expansion both radially and inwards

ERSATZBLA7T Axial direction with respect to the axial direction of the artery and thus a sliding of parts of the balloon along the artery, with the result that the artery can not be completely closed even with maximum balloon filling. As a result, the amount of compression fluid, usually saline solution, which is necessary in order to compress the artery sufficiently, but not too strongly, cannot be precisely predetermined. As a result of the balloon being pressurized differently with regard to the direction as well as the strength of the different pressurization at the different locations of the artery, the artery is "pinched" and in the long term the artery wall is damaged. The balloon itself is also subject to material fatigue in a relatively short time, with the result that the elasticity of the balloon wall changes. The need to produce a technically difficult suture in the area of the silicone band ends has also proven to be disadvantageous, since care must be taken to ensure that the artery is not damaged.

Proceeding from this, the invention is based on the object of further developing the oecluder of the type mentioned at the outset in such a way that the aforementioned disadvantages of the conventional design are eliminated and the artery is acted upon uniformly and practically exclusively radially.

The ocluder according to the invention, in which this object is achieved, is essentially characterized in that the deformable membrane is designed as an inner boundary wall of the chamber formed in a hollow cylindrical body, that the body enables it to be applied to the artery Separation gap parallel to the axis and an outer boundary wall which is practically not expandable when the chamber is pressurized, but which can be bent, which is connected to the inner

REPLACEMENT LEAF Boundary wall is connected along the separation gap and in the area of the front body edges at the end of the chamber and that the separation gap edges can be connected to one another after the body has been applied to the artery.

Since the body of this thus cylindrical occluder consists of bendable or elastically resilient material, it can be elastically expanded in the area of the separating gap edge and placed around the artery against which the inner boundary wall of its chamber comes to rest. After the separation gap edges have been connected, the non-expandable outer boundary wall, when the chamber is pressurized, ensures that only the inner boundary wall of the chamber formed in the body, which is in contact with the artery, is deformed inward towards the artery, and in this case two opposite wall regions move towards each other until they finally act on both sides of the artery and stop the blood supply through the artery. Since the forces act perpendicular to the longitudinal axis of the arteries, this advantageously results in a uniform application. Forces acting in the longitudinal direction are absorbed by the non-expandable outer boundary wall and consequently cannot act on the artery. Due to the. The relationship between the amount of compression fluid supplied, usually saline, and the resulting deformation of the inner boundary wall and thus the pressure on the artery, can be used to clearly determine the compression forces by appropriately measuring the amount of fluid during the operation. A very stable construction of the occluder can thus be created without having to accept any functional disadvantages. Even arterial pressures above the norm and greater resistance of the arterial walls can be overcome and material fatigue can be prevented too quickly. The light and the diameter of the artery can be easily adjusted

EF.SETZBLATT create suitable ocluder, ie oecluder that have different lengths and diameters according to the respective needs.

A particularly simple embodiment of the occluder according to the invention is distinguished by the fact that the outer boundary wall is secured against radial and axial expansion by stronger dimensions in comparison to the inner boundary wall. A wall / thickness ratio of approximately 2: 1 is expediently chosen.

If the body and thus the outer boundary wall as well as the inner boundary wall consist of elastically flexible material, certain, if small, widenings can still occur in the outer wall area despite different wall thickness measurements. In order to practically completely eliminate this possibility, and even to achieve a reduction in wall thickness, it has proven to be advantageous if a casing in the form of an inextensible sleeve is assigned to the outer boundary wall. It has been shown that in this way the oecluder can be dimensioned much smaller, in particular with regard to its diameter.

In a further embodiment, it is the same

Objective, namely reduction in size, is advantageous if a resistance-resistant material preventing the expansion is integrated in the outer boundary wall. It is particularly favorable if the resistant material is formed by a fabric.

In a further embodiment it has turned out to be very advantageous with regard to a simple structure and nevertheless easy handling if threads or tapes are around the

^' outer boundary wall are laid around or inserted into it, the ends of which are located in the region of the separating gap can be knotted together. With the help of these threads or tapes, the separation gap can be secured against undesired expansion. If it is an oecluder in which a resistance-resistant material in the form of tissue is incorporated in the outer boundary wall, it is advantageous if at least some threads of this tissue are led out to connect the separating gap edges and can be knotted together are. In this case, it therefore does not require the ^'arrangement of additional threads or bands, the separation gap edges are connected with the help of each other.

It has proven to be very advantageous if the separating gap edges interact with eyelets and hooks or

Hinges are assigned. The eyelets or hooks are expediently attached to the threads of the cuff or the inserted tissue that run out in the separating gap area.

Further details, advantages and features emerge from the following description with reference to the drawing, in which an embodiment of the occluder, for example, i.e. is illustrated in a non-restrictive, schematic and perspective manner.

As can be seen from the drawing, the illustrated ocluder comprises a hollow cylindrical body 1 made of elastically flexible, non-absorbable material, preferably silicone rubber, with a pressurizable chamber 2 between an inner boundary wall 3 and an outer boundary wall 4. Die inner boundary wall 3 is designed as a bare membrane deformability, while the outer B ^{'egrenzungswand} 4 Although bendable, but substantially non-expandable forms

REPLACEMENT LEAF is. The outer boundary wall 4 is with the inner boundary wall 3 in the region of the front, expediently rounded body edges 5, of which only the rear is indicated in the drawing, as well as along the edges 6 and 7 of a separation gap 8 to form the chamber 2 connected. The inside diameter of the body 1 corresponds approximately to the outside diameter of the artery which is to be temporarily closed with the aid of the occluder. The axially parallel separation gap 8 is used to apply it to the artery. The pressurizable chamber 2 extends practically over the entire axial and circumferential extent of the body 1. In the region of the front body edges 5 and the separation gap 8, the chamber 2 is, of course, closed to the outside. Pressure chamber, preferably a sterile saline solution, can be supplied to the chamber 2 via a catheter 9 which, in the exemplary embodiment shown, is fixed approximately in the central region of the hollow cylindrical body 1 and extends radially away from it and does not become clearer in FIG Subcutaneous tissue of a patient leads implanted ports. If necessary, the catheter 9 can also be fixed at another point on the outer boundary wall 4, for example also at one of the two front body edges 5, and in such a way that it encloses an acute angle with the axis of the hollow cylindrical body 1. The port can be filled by puncturing a silicone membrane delimiting the port chamber with the sterile saline solution up to the complete closure of the artery with appropriate expansion and also emptied again. In order to ensure that the outer boundary wall 4 does not deform as well and expand radially and axially as the inner boundary wall 3 when the chamber 2 is pressurized, in the illustrated example it is made sufficiently stronger than the latter, preferably twice as strong. Instead or additionally, a sheathing with an inextensible man

REPLACEMENT LEAF be provided. It is also possible, as in the

Drawing schematically indicated in dashed lines to store a resistance-resistant material, for example a fabric 10 in the outer boundary wall 4.

In order that the body 1 expands when the inner boundary wall 3 is pressurized and deformed in the region of the edges 6 and 7 of the separation gap 8, threads or bands are placed around the outer boundary wall 4, the ends of which are knotted together in the region of the separation gap 8. Instead, the threads or strips can also be embedded in the material of the outer boundary wall 4 and can be led out in the region of the separating gap 8. The drawing schematically indicates the possibility of leading some of the threads 11 of the embedded fabric 10 that extend around the chamber 2 to the outside in order to avoid widening by knotting their ends.

Instead, it is also possible to provide eyelets and hooks, hinges or the like interacting on the edges 6 and 7 of the separating gap 8, which serve as a separating gap closure, or also to use clamps with the aid of which the separating gap edges are connected to one another. If the outer boundary wall 4 is assigned a sleeve preventing its expansion, it can be very advantageous if the threads running out in the gap area are firmly connected to form a unit with elastic plastic eyelets or hooks in order to avoid knotting.

: RSATΣBLATT

Claims

1. Implantable ocluder for the temporary occlusion of arteries, in particular the hepatic artery for the purpose of temporary hepatic desarterialization, with a membrane that can be attached to the artery and delimits a chamber (2) by supplying pressure fluid to the chamber (2) - εclosed catheter (9) is deformable and serves to reduce the arterial cross-section to zero when pressure is applied, characterized in that the deformable membrane is an inner boundary wall (3) of the chamber formed in a hollow cylindrical body (1) (2) that the body has an axially parallel separating gap (8) which enables it to be applied to the artery and an outer boundary wall (4) which is practically non-expandable when the chamber (2) is pressurized, but which bends with the inner boundary wall (3) along the separating gap 8) and in the region of the front body edges (5) at the end of the chamber (2) is connected and that the separating gap edges (6, 7) can be connected to one another after the body (1) has been applied to the artery.

2. Oecluder according to claim 1, characterized in that the outer boundary wall (4) is secured by stronger dimensions compared to the inner boundary wall (3) against radial and axial expansion.

3. Oecluder according to claim 2, characterized by a wall thickness ratio of 2: 1.

4. Oecluder according to any one of claims 1 to 3, characterized in that a jacket in the form of an inextensible sleeve is assigned to reduce the wall thickness of the outer boundary wall (4).

5. Oecluder according to one of claims 1 to 4, characterized in that in the outer boundary wall (4) an expansion-preventing resistant material is integrated.

6. Oecluder according to claim 5, characterized in that the resistant material is formed by a fabric (10).

7. Oecluder according to one of claims 1 to 6, characterized in that threads or tapes are placed around or inserted into the outer boundary wall (4), the ends of which in the region of the separating gap (8) link to one another are noticeable.

8. Oecluder according to claims 5 and 6, characterized in that at least some threads of the fabric (10) embedded in the outer boundary wall (4) for connecting the separating gap edges (6 and 7) are led out and can be knotted together .

9. Oecluder according to one of claims 1 to 8, characterized in that the separating gap edges (6, 7) are associated with eyelets and hooks or hinges which act towards one another.

10. Oecluder according to claims 4 or 8 and 9, da¬ characterized in that the eyelets or hooks are fixed to the threads of the cuff or the embedded tissue that run out in the separating gap area.