DE102022101284A1 - feeding system - Google Patents

Abstract

The invention relates to a delivery system for an expandable medical functional element (10), in particular a stent, flow diverter or thrombectomy device, with at least two tubes (11, 12) and a transport wire (13), with a first inner tube (11) being arranged coaxially in a second outer tube (12) and both tubes (11, 12) being movable in the longitudinal direction relative to one another, the first inner tube (11) with the functional element (10) in front is charged, the functional element (10) being arranged in the lumen of the first inner tube (11), the transport wire (13) being connected to the functional element (10) and the inner tube (11) being fixable in at least one axial direction in order to transmit an axial force between the two tubes (11, 12) in order to release the functional element (10).

Description

The invention relates to a delivery system for an expandable medical functional element, in particular a stent, flow diverter or thrombectomy device, according to the preamble of patent claim 1.

In general, delivery systems are used to guide an expandable medical functional element, such as a stent, flow diverter or thrombectomy device, in the compressed state to a designated location in the vascular system, with the aim of inserting the functional element there after it has been released in the expanded state.

Delivery systems usually include a catheter and a transport wire on which the functional element is arranged. In use, the distal end of the catheter is first guided to the intended location in the vascular system. In order to deliver the functional element, the functional element is then advanced in the compressed state through the lumen of the catheter to the intended location with the aid of the transport wire. The catheter counteracts the expanding property of the functional element and thereby keeps the functional element in the compressed state. As soon as the functional element is in the intended location, the catheter is pulled in the proximal direction and the functional element is released.

Such delivery systems have disadvantages. The catheter must have increased rigidity in order to keep the functional element in the compressed state against its expansion force. For this reason, conventional catheters are made up of a number of functional layers, in particular a reinforcing mesh, which require an increased wall thickness. The increased rigidity and wall thickness of the catheter makes it difficult to navigate the delivery system to its intended location in the vasculature. An application of these delivery systems in vascular areas with narrow lumens, in particular in distal regions of the intracranial vascular system, is therefore restricted.

U.S. 5,690,644 A describes a generic delivery system with two mutually coaxially arranged catheters. In this delivery system, an expandable medical functional element is arranged between the outer wall of a first inner catheter and the inner wall of a second outer catheter, with the inner catheter serving as a carrier for the functional element and the outer catheter holding the functional element in the compressed state. In use, both catheters, together with the preloaded functional element, are guided as a unit over a previously positioned guide wire to the intended location, with the guide wire running through the lumen of the inner catheter. The disadvantage of this delivery system is the increased rigidity of the outer catheter, which is required to maintain the compressed state of the functional element and which is additionally reinforced by its being preloaded with the functional element. This makes navigation along the guide wire more difficult and restricts its use in vascular areas with narrow lumens, particularly in distal regions of the intracranial vascular system.

It is the object of the present invention to improve a delivery system of the type mentioned at the outset in such a way that handling during navigation of the delivery system and during delivery and release of the functional element in vascular areas with narrow lumens, in particular in the intracranial vascular system, is simplified.

According to the invention, the object is achieved by a feed system having the features of claim 1.

The invention is based on the idea of specifying a delivery system for an expandable medical functional element, in particular a stent or thrombectomy device, with at least two tubes and a transport wire. In use, a first inner tube is coaxially disposed within a second outer tube, both tubes being longitudinally movable relative to one another. According to the invention it is provided that the first inner tube is preloaded with the functional element, the functional element being arranged in the lumen of the first inner tube and the transport wire being connected to the functional element. Furthermore, the inner hose can be fixed in at least one axial direction in order to transmit an axial force between the two hoses in order to release the functional element.

The invention has the advantage that the navigation of the delivery system and the delivery of the functional element are structurally decoupled. The delivery system navigates to the intended site through the outer tube. The inner hose is provided for the supply of the functional element, in the lumen of which the functional element is preloaded.

In use, ie during the operation, the distal end of the outer hose is first guided to the intended location in the vascular system. In order to supply the functional element, the inner hose preloaded with the functional element is then inserted through the lumen of the outer advanced hose to the intended point. The inner tube counteracts the expanding property of the functional element, ie counteracts the expansion force, and thereby keeps the functional element in the compressed state. As soon as the distal ends of both tubes are flush, the inner tube is fixed and the functional element is released using the transport wire.

The resulting separation of functions enables the function of each component to be optimized independently of the function of the other component. Since the outer hose guides the inner hose to the intended location, while the inner hose keeps the functional element in the compressed state independently of the outer hose, both the navigation of the outer hose and the feeding of the functional element through the inner hose are facilitated.

The present invention therefore takes a different approach than the prior art, which further develops special catheters that are designed both for navigating the delivery system and for delivering the functional element. Rather, in a delivery system according to the invention, these two tasks are divided between at least two simple hoses which are arranged coaxially and are longitudinally movable with respect to one another. This simple design has the further advantage that a delivery system according to the invention can be designed to be more compact compared to the prior art. This further facilitates use in vascular areas with narrow lumens, particularly in distal regions of the intracranial vascular system.

The invention is therefore not about two separate catheters that are used together and are each designed to be guided in the vessel lumen. The delivery system according to the invention forms a multi-tube catheter that can be handled as a unit, in particular a two-tube catheter. The inner tube is not designed to be routed directly into a vessel lumen. The inner tube is designed to be routed within the lumen of the outer tube to the distal end of the outer tube.

The inner hose acts as a transport hose for the functional element. The possibility of fixing the inner hose in order to transmit an axial force between the two hoses means that the functional element can be released at the desired point in the vessel to be treated by the interaction of the two hoses. Release usually occurs immediately following the distal end of the outer tube.

The constructive decoupling of the navigation of the feed system and the feed of the functional element has further advantages. Because the inner tube is preloaded with the functional element, the functional element does not have to be advanced along the entire length of the delivery tube. This makes feeding easier and creates more freedom in the design of the functional element. Furthermore, different materials can be used for the outer and inner tubes to accommodate the different requirements of the two tubes. However, the same materials can also be used. Furthermore, as a result of the easier navigation, potential sources of error when navigating the feed system are reduced. In addition, the duration of the intervention and thus the risk of medical interventions is reduced.

A preferred embodiment of the invention provides that a radial gap is formed between the first inner hose and the second outer hose. In this way, on the one hand, an essentially smooth, but at least low-friction, longitudinal mobility of the two hoses relative to one another is achieved. In addition, this additionally supports the advantageous decoupling of the navigation of the feed system and the feed of the functional element.

In a further preferred embodiment, the transport wire has a connection means for connection, in particular a positive connection, to the functional means. This connecting means is used to transmit a movement or force from the transport wire to the functional element, for example in order to release the functional element. The connection between transport wire and functional element realized by the connecting means can be designed to be detachable, preferably for medical treatment devices that remain permanently in the vascular system, such as stents or flow diverters, or fixed, preferably for medical treatment devices that temporarily remain in the vascular system, such as thrombectomy devices.

Preferably, the first inner tube has an equal or greater axial stiffness than the second outer tube. Such a design of the two hoses ensures good navigability of the outer hose with good feedability of the inner hose. This will enable the advantageous decoupling of Naviga tion of the feed system and feed of the functional element further improved.

In a preferred embodiment, the first inner tube is longer than the second outer tube. In this way it can be ensured that the second outer tube does not come into contact with elements that are arranged in the lumen of the first inner tube, in particular the functional element and transport wire. The second outer hose can thus be designed free of requirements that would result from contact with these elements, for example with regard to compatibility or strength.

The first inner hose is preferably shorter than the transport wire. In this way it can be ensured that both ends of a transport wire arranged in the lumen of the first inner tube can protrude from the first inner tube. For example, the treating physician can grip the transport wire at the proximal end, while the distal end of the transport wire projects out of the first inner tube to release the functional element.

It is furthermore preferred that the first inner tube has at least two layers, in particular a sliding layer and a reinforcing layer. In one embodiment, the first inner hose has exactly two layers, in particular a sliding layer and a reinforcing layer.

In order to ensure high axial rigidity, it is preferably provided that the reinforcement layer of the first inner tube has a polyimide layer. This facilitates the advancement of the first inner tube, in the lumen of which the functional element is preloaded, through the second outer tube.

For good sliding properties it is advantageous if the sliding layer of the first inner hose has a PTFE layer, an FEP layer or an HDPE layer. This reduces frictional forces between the functional element and the inner hose, such as can occur when the functional element is preloaded and released, for example.

The second outer hose preferably has at least two layers, in particular a reinforcement layer and an outer layer. In one embodiment, the second outer hose has exactly two layers, in particular a reinforcement layer and an outer layer.

In order to achieve high strength with low rigidity, the reinforcement layer of the second outer hose preferably has a slotted hypotube.

The outer layer of the second outer tube preferably comprises at least peba, polyurethane or polyamide.

Furthermore, in one embodiment of the invention it can be provided that the second outer hose comprises a third layer, in particular a biocompatible inner layer. As a result, the biocompatibility can be additionally improved.

A further preferred embodiment of the invention provides that the two hoses can be connected to one another in order to fix the first inner hose. Such a connection, in particular a form-fitting connection, can prevent the mobility of the inner hose relative to the outer hose, at least in the distal direction or in the distal and proximal directions. This creates the possibility of exerting a relative movement between the two hoses and the transport wire in order to release the functional element.

In this case, the second outer hose preferably has a stop means which interacts with the first inner hose to release the functional element. In this way, the functional element can be released as a unit in the proximal direction by advancing the transport wire in the distal direction and/or pulling back both hoses. The first inner hose can also have a stop means which interacts with the second outer hose to release the functional element.

• 1 einen Längsschnitt eines Zuführsystems nach einem erfindungsgemäßen Ausführungsbeispiel;
• 2 eine Detaildarstellung der Verbindung zwischen Transportdraht und Funktionselement des Zuführsystems aus 1;
• 3 eine Detaildarstellung des Transportdrahtes, des Funktionselementes und der beiden Schläuche des Zuführsystems aus 1;
• 4 einen Längsschnitt des Zuführsystems aus 1 im Ausgangszustand vor der Operation;
• 5 einen Längsschnitt des Zuführsystems während der Operation bei teilweiser Freisetzung des Funktionselements;

The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying schematic drawings. Show in it:

• 1 a longitudinal section of a delivery system according to an embodiment of the invention;
• 2 shows a detailed representation of the connection between the transport wire and the functional element of the delivery system 1 ;
• 3 a detailed view of the transport wire, the functional element and the two hoses of the delivery system 1 ;
• 4 a longitudinal section of the delivery system 1 in the initial state before the operation;
• 5 a longitudinal section of the delivery system during the operation with partial release of the functional element;

A preferred embodiment of a delivery system is shown in the accompanying figures. The delivery system is used to guide an expandable medical functional element 10 in the compressed state to a designated location in the vascular system, with the aim of using the functional element 10 there after being released in the expanded state.

The functional element 10 is tubular and has a latticework. The lattice mesh can have wire braided meshes or a cut web structure. The functional element is made from a self-expanding material. It can include different treatment devices, such as a stent or flow diverter that remains permanently in the vascular system, or a thrombectomy device that remains temporarily in the vascular system and is removed after the treatment. Flow diverters are also referred to as embolization devices, which are used, for example, to treat aneurysms. Other treatment facilities are possible.

The delivery system shown in the attached figures comprises two hoses 11, 12 and a transport wire 13.

1 shows an arrangement of the delivery system in use, ie during the operation. The hoses 11, 12 are arranged coaxially. The inner tube 11 is located in the lumen of the outer tube 12 . The inner tube 11 is preloaded with the functional element 10 , with the functional element 10 being arranged in the lumen of the inner tube 11 . The expandable functional element 10 is surrounded by the inner wall of the inner hose 11 and is therefore in a compressed state.

The inner tube 11 is designed to absorb the radial expansion force of the functional element 10 and to keep it in the compressed state. Due to the separation of functions, it is not necessary to design the outer tube 12 accordingly, since it does not have to absorb any expansion forces of the functional element.

Both hoses 11, 12 can be moved relative to one another in the longitudinal direction. Thus, during the operation, the inner tube 11 preloaded with the functional element 10 can be guided through the lumen of the previously positioned outer tube 12 to the treatment site. The inner hose 11 keeps the expandable functional element 10 in the compressed state independently of the outer hose 12 . This ensures that the hoses 11, 12 can move in the longitudinal direction relative to one another.

In order to further increase the mobility of the hoses 11, 12 in the longitudinal direction relative to one another, a radial gap 14 is formed between the inner hose 11 and the outer hose 12. It is harmless if the two hoses 11, 12 touch each other in places during use, since overall the contact surface between the two hoses 11, 12 is reduced by the radial gap 14. It goes without saying that the radial gap 14 does not run symmetrically like an annular gap between the two hoses 11, 12 during use, but can vary depending on the relative position of the two hoses 11, 12 to one another.

The width of the gap 14 results from the difference between the outside diameter of the inner hose 11 and the inside diameter of the outer hose 12. The gap 14 has a width of at least 25.4 μm, in particular at least 30 μm, in particular at least 35 μm. The width of the gap 14 is at most 50.8 μm, in particular at most 45 μm, in particular at most 40 μm. The combinations of the above lower and upper limits are disclosed.

The transport wire 13 is permanently or detachably connected to the functional element 10 . The functional element 10 is arranged on the transport wire 13 and is fixed in the longitudinal direction relative to the transport wire 13 by a connecting element 15 attached to the transport wire 13 .

The inner tube 11 can be fixed in at least one axial direction in order to transmit an axial force between the two tubes 11, 12. In other words, both hoses 11, 12 can be fixed in a desired position relative to one another, so that at least the inner hose 11 is prevented from escaping from the outer hose 12 in the distal direction.

The inner tube 11 can be fixed relative to the outer tube 12 in the distal direction, for example in the form of a stop means on the outer tube 12 which interacts with the inner tube 11 (not shown). The stop means can be attached, for example, to the inner circumference of the outer tube 12 and protrude into its lumen.

The inner hose 11 has a counterpart, for example the face of the distal end of the hose or another counterpart, which strikes the stop means in the desired position and prevents the inner tube 11 from being moved beyond the desired position. The desired position is preferably the substantially flush position of the distal tube ends of the inner and outer tube 11, 12. In other words, the stop means causes the distal tube ends of the inner and outer tube 11, 12 to be approximately or exactly at the same height at least in an axial direction can be fixed.

It is also possible for the outer circumference of the inner hose 11 to have a stop means, which interacts with the outer hose 12, in order to fix the inner hose 11 in place. Instead of a stop means, the outer tube 12 can also have a taper in order to fix the inner tube 11 relative to the outer tube 12 in the distal direction. In addition, it is also possible for the two hoses 11 , 12 to be able to be connected to one another in order to fix the first inner hose 11 . Other versions of the fixation of the inner hose 11 are possible.

The fixability of the inner hose 11 relative to the outer hose 12 makes it possible to prevent a movement of the two hoses 11, 12 relative to one another. The fixability serves not only to prevent the inner tube 11 from escaping from the outer tube 12 in the distal direction, but also to enable or control the release of the functional element through axial force transmission between the tubes 11, 12.

In this way, the functional element 10 can be moved in the longitudinal direction relative to the two hoses 11, 12 by means of the connected transport wire 13, without the inner hose 11 also being moved. In other words, the two hoses 11, 12 fixed in the desired position relative to one another can be moved or pulled back as a unit relative to the functional element 10 in the proximal direction.

If, for example, the outer tube 12 is moved in the proximal direction relative to the transport wire 13, the inner tube 11 is also moved by the movement of the outer tube 12 as a result of the fixation. The functional element 10, which is connected to the transport wire 13 and held stationary, is thereby moved in the distal direction relative to the inner tube 11 and can thus be released.

If a stop means is used for axial fixing, the stop means acts as an abutment in order to bring about the transmission of force, in particular the frictional forces, from the functional element 10 to the two hoses 11, 12.

The inner tube 11 is longer than the outer tube 12. In addition, the inner tube 11 has a length that is smaller than the length of the transport wire 13. The difference in length between the inner tube 11 and the outer tube 12 is at least 1 cm. The upper limit of the length difference is a maximum of 15 cm, in particular a maximum of 5 cm.

This design of the tubes 11, 12 can prevent contact between the elements that are arranged in the lumen of the inner tube 11 and the outer tube 12 during the operation. A transport wire 13 that is longer than the inner tube 11 ensures that, for example, the attending physician can grasp the transport wire 13 at the proximal end in order to release the functional element 10 by means of the transport wire 13 at the distal end of the inner tube 11 .

An X-ray marker (not shown) can also be attached to the distal end of the inner tube 11 and/or outer tube 12 in order to identify the position of the inner tube 11 and/or outer tube 12 during the operation.

2 shows a sectional view of the connection of functional element 10 and transport wire 13. The connecting element 15 is designed as a ring with a profiled outer circumference, in particular a tooth-like profiled outer circumference. The ring-shaped connecting element 15 is fixed coaxially to the outer circumference of the transport wire 13 so that the profiled outer circumference of the connecting element 15 points radially outwards, starting from the outer circumference of the transport wire 13 . The functional element 10 encloses the transport wire 13 and lies against the transport wire 13 as a result of its compressed state. The profiled outer circumference of the connecting element 15 , for example in the form of teeth, engages in the mesh or lattice structure of the functional element 10 . As a result, the transport wire 13 is positively connected to the functional element 10 and fixed relative to the functional element 10 in the axial direction.

In 3 is a longitudinal section of the delivery system 1 shown in detail. The inner tube 11 consists of two layers, an inner layer 16 and an outer layer 17. The inner layer 16 represents the contact surface between the expandable functional element 10 and the inner tube 11, which holds the functional element 10 in the compressed state To achieve an exercise-free or low-friction relative movement between the functional element 10 and the inner tube 11, for example when the functional element 10 is released, the inner layer 16 is designed as a sliding layer. The inner layer 16 can be made of PTFE, for example, in order to ensure good sliding properties. In order to facilitate guiding of the inner tube 11 through the lumen of the outer tube 12, the outer layer 17 of the inner tube 11 is designed as a reinforcement layer. The outer layer 17 can have a polyimide layer, for example, in order to increase its tensile strength. The inner layer 16 and the outer layer 17 have an identical wall thickness. However, the wall thicknesses can also be different.

The outer tube 12 can have two or more layers. A thin-walled reinforcement layer, for example designed as a slotted hypotube, can be encased by an outer layer that can consist of one or more materials, for example Peba, polyurethane and polyamide. The biocompatibility of the outer hose 12 can be improved by means of a further inner layer.

Both hoses 11, 12 are free of reinforcement braids.

In order to further facilitate the guiding of the inner tube 11 through the lumen of the outer tube 12 , the inner tube 11 preferably has an equal or greater axial rigidity than the outer tube 12 .

In 3 it becomes clear that a gap 14 is formed between the inner tube 11 and the outer tube 12 . The inner tube 11, which holds the expandable functional element 10 in the compressed state, and the outer tube 12 are structurally separated from one another by the gap 14. This design measure increases the mobility of the hoses 11, 12 in the longitudinal direction relative to one another.

In 4 is a longitudinal section of the same delivery system as 1 presented in an arrangement that is present before use, ie before the operation. The two hoses 11, 12 are separate from each other and are in 4 shown side by side. The inner tube 11 is preloaded with the functional element 10 , the functional element 10 being arranged in the lumen of the inner tube 11 . The functional element 10 is attached to the transport wire 13 and is positively connected to the transport wire 13 via the connecting element 15 .

In order to carry out a medical surgical intervention using the delivery system, the outer tube 12 is first guided to the point to be treated in the vascular system with the aid of a guide wire (not shown). Once the outer tube 12 is in place, the guidewire is removed. The inner tube 11 preloaded with the functional element 10 is then guided through the lumen of the outer tube 12 until the distal end of the inner tube 11 is flush with the distal end of the outer tube 12 . As soon as the distal ends of both hoses 11, 12 are flush, the inner hose 11 is fixed relative to the outer hose 12. A stop means, which is attached to the inner circumference of the outer tube 12, can, for example, prevent the inner tube 11 from exiting in the distal direction by transmission of axial force and thus fix it.

5 shows the same delivery system during the operation with partial release of the functional element. The distal ends of both hoses 11, 12 are arranged flush. The inner tube 11 is fixed relative to the outer tube.

An axial movement of the two hoses 11, 12 fixed to one another as a unit in the proximal direction moves the functional element 10 connected to the transport wire 13 in the distal direction relative to the two hoses 11, 12 and is thereby released. The released part of the functional element 10 assumes an expanded state. As long as the connecting element 15 is in the lumen of the inner tube 11, the functional element 10 is connected to the transport wire 13. The part of the functional element 10 that has already been released can be pulled back into the lumen of the inner hose 11 because of the existing connection. If the connecting element 15 is located outside of the inner hose 11, the connection between the transport wire 13 and the functional element 10 is released and the functional element 10 is released irreversibly.

Reference List

10

functional element

11

inner tube

12

Outer hose

13

transport wire

14

gap

15

fastener

16

Inner layer of the inner tube

17

Outer layer of the inner tube

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US5690644A [0005]

Claims (15)

Delivery system for an expandable medical functional element (10), in particular a stent, flow diverter or thrombectomy device, with at least two tubes (11, 12) and a transport wire (13), with a first inner tube (11) being held in a second outer hose (12) is arranged coaxially and both hoses (11, 12) can be moved relative to one another in the longitudinal direction, characterized in that the first inner hose (11) is preloaded with the functional element (10), the functional element (10) being in lumen of the first inner tube (11), the transport wire (13) is connected to the functional element (10) and the inner tube (11) can be fixed in at least one axial direction in order to release the functional element (10) by exerting an axial force between to transfer the two hoses (11, 12). feeding system after claim 1 characterized in that a radial gap (14) is formed between the first inner tube (11) and the second outer tube (12). feeding system after claim 1 or 2 characterized in that the transport wire (13) has a connecting means (15) for connection, in particular a positive connection, to the functional means (10). Delivery system according to one of the preceding claims, characterized in that the first inner tube (11) has an equal or greater axial rigidity than the second outer tube (12). Delivery system according to one of the preceding claims, characterized in that the first inner tube (11) is longer than the second outer tube (12). Delivery system according to one of the preceding claims, characterized in that the first inner tube (11) is shorter than the transport wire (13). Delivery system according to one of the preceding claims, characterized in that the first inner tube (11) has at least two layers, in particular a sliding layer and a reinforcing layer. feeding system after claim 7 characterized in that the reinforcement layer comprises a polyimide layer. feeding system after claim 7 or 8th characterized in that the sliding layer has a PTFE layer, an FEP layer or an HDPE layer. Delivery system according to one of the preceding claims, characterized in that the second outer tube (12) has at least two layers, in particular a reinforcement layer and an outer layer. feeding system after claim 10 characterized in that the reinforcement layer comprises a slotted hypotube. feeding system after claim 10 or 11 characterized in that the outer layer comprises at least peba, polyurethane or polyamide. Feeding system according to one of Claims 10 until 12 characterized in that the second outer tube (12) comprises a third layer, in particular a biocompatible inner layer. Delivery system according to one of the preceding claims, characterized in that the two hoses (11, 12) can be connected to one another in order to fix the first inner hose (11). feeding system after Claim 14 characterized in that the second outer tube (12) has a stop means which interacts with the first inner tube (11) to release the functional element (10).

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