KR20070020380A - Flexible delivery system - Google Patents

Abstract

An articulation device for advancing a medical implant along a catheter includes a plurality of segments (1, 12) arranged side by side, each segment hingedly connected to one adjacent segment if not at the end of the column. In this case, by connecting to two adjacent segments, the medical implant mounted at one end of the device can be advanced through the catheter by pushing the other end of the device, and the hinge connection allows the device to move along a curved path through the catheter. do.

Segment Device, Segment, Medical Implant, Hinge Connection, Catheter

Description

Flexible Delivery System {FLEXIBLE DELIVERY SYSTEM}

The present invention relates to a segmentation device for advancing a medical implant along a catheter. In particular, the present invention relates to a tubular or catheter based flexible delivery system for introducing an implant into a patient through a point remote from the inlet. The present invention is an improvement on the existing delivery system most commonly used to deploy artificial vascular stents in the aorta by placing the artificial vascular stents into the artery using the entry point in the iliac or common femoral arteries.

Artificial vascular stents configured for implantation in the aorta today are radially compressed by 4 times to require a delivery system with a diameter of approximately 7 mm in a transplanted tissue of typically 28 mm in diameter.

This diameter of the delivery system is small enough to allow a physician to make a minimal incision, but it is difficult to achieve the flexibility required to reach the delivery site through the vascular tree.

Zenith, manufactured by Cook Inc., Talent, manufactured by Medtronic Inc. and Anneurx, likewise manufactured by Medtronic. Many artificial vascular stent delivery systems, such as, include the outer shell and inner "retainer" rods as major components. In use, the artificial vessel stent is compressed and inserted into the end of the shell and the retainer rod is inserted from the distal end of the shell until it contacts the artificial vessel stent. The envelope and its contents are introduced through the vascular system by various means until the portion of the envelope containing the artificial vessel stent is positioned at the desired landing site for the artificial vessel stent. The skin is then slowly pulled backwards, but the artificial blood vessel stent is held in place by the retainer rod. As the sheath continues to be pulled backwards, the artificial vessel stent begins to exit from the open end of the sheath, and the deployment operation is completed when the end of the sheath is pulled back to a point that is flush with the end of the retainer rod.

US Pat. No. 6,589,227 (William Cook Europe APS) discloses an endovascular device for delivering expandable prostheses into body lumens. The device is formed of multiple filament groups of individual wire coils.

US Patent No. 6,464,716 (Innercool Therapies, Inc.) discloses an intravascular heat transfer device formed of a plurality of elongated joint segments connected by a flexible joint formed of bellows or a flexible tube. . The device is used to regulate the temperature of the brain in controlling body temperature, especially hypothermia.

Other implant devices are disclosed in US Pat. No. 5,954,729 (Scheneider, USA) and European Patent 0 518 838 (AMS Medinvent SA).

In particular, the retainer rod is flexible enough to allow the delivery system to follow the curvature of the arterial tree. However, the force required to deploy the artificial vessel stent can be quite high and the retainer rod can be compressed axially as the artificial vessel stent is deployed. This compression action is undesirable because it can reduce deployment accuracy and can cause radial expansion of the retainer rods. Such radial expansion can prevent the device from further deployment by locking the retainer rod into the shell.

Another condition for the retainer rod is that it must be able to transfer torsional motion by the handle of the delivery system up to the artificial vessel stent. In a successful delivery system, the position of the device must be precisely controlled so that the shape of the artificial vessel stent on rotation matches the anatomical structure. If the retainer rods are too soft or elastic, the control of the device using the handle is inaccurate, making it difficult to ensure, for example, that the damaged leg of the branched graft tissue lies on a plane parallel to the target vessel.

Thus, flexible conditions suggest the use of soft materials in the retainer rods, while torsion control and incompressible conditions suggest the use of rigid materials.

According to the invention, one partial solution of these contradictory conditions is to use a rigid material for the retainer rods but cut the retainer rods into several short segments which are freely segmented with respect to each other.

This solution is shown in FIG. 1 as two segments of retainer rods segmented with respect to each other to provide a flexible retainer rod that is incompressible.

The solution of the present invention is compromised by relying on the presence of the shell to prevent the segment from moving and also having no mechanism for transmitting torque from one segment to the next. Obviously, the actual device will require various segments of the type shown in FIG.

Another problem with this approach is that its length increases as the composite retainer bar is bent, making this approach useless for applications that require a high degree of flexibility.

An improvement over this first structure is shown in Figure 2, which uses a segment made of hard material as before but chamfers the contact end of the segment so that the segment angle can be increased before the retainer rods are lengthened. )

Further modifications to the contact surface can be devised to provide further features with the retainer rods having a segmented structure and the contact surface set to the principles shown in FIGS. 1 and 2 modified to improve the overall properties. .

According to one aspect of the invention, a segmental device for advancing a medical implant along a catheter, comprising: a plurality of segments arranged side by side, each segment hinged to one adjacent segment when at the end of the column By connecting to two otherwise adjacent segments, the medical implant mounted at one end of the device can be advanced through the catheter by pushing the other end of the device, and the hinged connection allows the device to curve through the catheter. Characterized in that to move along the path.

Providing segments with hinged connections between the segments means that these segments are formed of a relatively rigid material (such as a thermoset plastic material or even a metal or metal alloy), and as a result the device is subjected to medical implants with high torsional forces applied from the collector. That means you can deliver it with water.

In a preferred embodiment, the segment is formed of glass reinforced polyphenylene sulfide (provided under the trade name Fortron® in Ticona). Devices assembled with these segments can deliver moments of 1 Nm and can hold up to 760 N of compression force with little shortening. Thus, in a preferred embodiment, the device may be formed of a material capable of transferring a moment of at least 0.5 Nm, more preferably at least 0.75 Nm and most preferably 1 Nm. The minimum supportable compressive force which hardly causes shortening is preferably 300 N, more preferably 500 N and most preferably 750 N.

Preferably, the segments are detachable so that devices of any length can be assembled by simply increasing the number of segments.

In order to effectively transfer torque from one segment to another, the segment may include at least one side workpiece to engage with the corresponding elongated opening in the contact segment.

Ideally, the contact surface has a partially spherical end to allow maximum bending angle between adjacent contact surfaces.

In a preferred embodiment, each segment has a male part (which may include balls and / or a pair of protrusions) and a female part (which may include a socket and / or a pair of slots). and a male portion of one segment can engage with a female portion of an adjacent segment and a female portion can engage with a male portion of an adjacent segment.

Preferably, the connection structure between each segment is a snap-fit structure that allows straight connection of the segments while preventing the segments from being easily separated in use. For example, the inlet of the slot on the female part may be slightly narrower than the outer diameter of the protrusion on the male part, whereby it is necessary to apply a small force to separate the jaw of the slot so that the protrusion can pass through it. Thereafter, the width of the slot extends slightly above the slot inlet to accommodate the protrusion upon the sliding slide fitting. Segments are relatively rigid as a whole, but in this embodiment the segments should be formed of a material that can be elastically bent to accommodate the protrusions on adjacent segments.

Ideally, the actual structure for a 21 French (7 mm diameter) delivery system uses segments that are 6 mm in diameter and 10.5 mm in length. These dimensions can be adjusted larger or smaller to provide a larger or smaller delivery system. Thus, a 10 French system uses segments that are approximately 3 mm in diameter and a 50 French system requires segments that are 15 mm in diameter. The ratio of the length to the diameter of the segment is preferably 1.75: 1, although the manufacturing is less laborious and improves flexibility if the ratio is limited between 1.5: 1 and 3: 1, the ratio is increased to 5: 1. Machinable designs can be made. At the expense of some reduction in strength, the ratio of length to diameter can be reduced to 1: 1. It is not desirable to make the length of the segment smaller than the width, because such segments are easier to swing in the shell and cause clogging.

The maximum segment angle between any two segments is defined as the angle at which the longitudinal axis of one segment forms with the longitudinal axis of the adjacent segment. This mainly depends on the nature of the hinged connection structure between the two segments. When using a ball and a socket as a preferred embodiment, the segment angle depends on the relative size of the inlet of the socket and the outer diameter of the segment at the segment portion that is aligned with the inlet of the socket when the two segments are connected. In a preferred embodiment, the maximum bending angle is at least 15 ° and preferably at most 25 °.

Segments are configured to be easily manufactured, and injection molding with appropriate hard, sterilizable plastics is a convenient technique. Preferably, one segment is configured such that the features on the first contact surface correspond to the counterfeits of the second contact surface. Although not convenient, it is possible to configure the segments to be joined in pairs. In the case of one segment, although each segment can be made with a single injection molding tool, a plurality of units can be stacked to form an elongated rod-shaped structure.

Preferably, each segment has a central axial hole through which the guide conductor and the surrounding structure can pass. For example, the guide lead (s) may be retained in a tube having an outer wall that smoothly reduces friction between the tube and the segment.

In one embodiment, the tube is attached to both ends of the end segment such that the inner segment is retained therebetween. The advantage of this is that when the segment is separated from the adjacent segment, it is retained on the tube like the pearl of a necklace.

For some applications, there is an advantage, for example, of assembling the device into groups of segments such that the group of segments closest to the handle is less flexible than the segments at the tip. Thus, the apparatus may consist of at least two types of segments in which the first type of segment has different characteristics from the second type of segment.

Preferably, the sidewalls of the segment have some cylindrical shape such that the profile of the shell on top of the segment is smooth and continuous even when the bending angle is excessive.

Positions off the central axis of the segment may be provided with additional lumens in the shape of grooves. It will be apparent to one skilled in the art that another groove may be located at another point around the segment periphery.

Conventional delivery systems may require from 15 to 80 of the aforementioned segments, depending on the length of the device. However, for some embodiments, more (eg 1000) segments may be used to obtain a total length of 2-3 m.

At both ends of the device a modified segment or end segment is used so that an effective interface can be made between the handle part and the segment device at one end and the implant and segment device at the other end. In either case, the end segment may be configured to match the handle and the implanted part, but this feature of the end segment in contact with the segmented device may allow torque and lumen to be transmitted through other components and retain flexibility. Hold all the combined features so that.

According to a second aspect of the invention, there is provided a kit comprising the above-described device and a medical implant mounted on one end of the device.

According to a third aspect of the invention, there is provided a segment for the device described above.

According to a fourth aspect of the invention, there is provided a method of advancing a medical implant along a catheter, the method comprising the steps of: providing a device as described above with an implant mounted on one end, and inserting the end of the device into the catheter And, pushing on the other end of the device.

Hereinafter, various preferred embodiments of the present invention will be described with reference to the drawings.

1 illustrates a basic segmented retainer rod that includes cylindrical segments of a simple planar joint.

FIG. 2 shows an improved form of the retainer bar of FIG. 1 with chamfering to allow greater bending angles without significantly changing the length of the contact surface.

3 shows a segment suitable for an apparatus according to the invention.

4 shows two segments of the type shown in FIG. 3 connected in an apparatus according to the invention.

First, FIG. 3 shows the actual configuration of the segment, including the additional features for transmitting torque, allowing additional longitudinal structures and maximizing the smoothness of the shell when bent while using the features shown in FIGS. 1 and 2. .

Segment 1 comprises an elongate integral member formed of glass reinforced polyphenylene sulfide that is approximately 10.5 mm long and approximately 6 mm wide at its maximum point.

The segment 1 has a male part 2 and a female part 3 which meet at the neck 4, and the male part 2 of one segment is configured to engage the female part 3 of the adjacent segment. Thus, the end portion and the end portion can be connected by connecting the male portion and the female portion corresponding to each other.

In particular, the male part 2 comprises a ball 5 in which a pair of lugs 6 protrude laterally in an axis perpendicular to the longitudinal axis of the segment 1. The female part 3 has a socket joint 9 with a lip 11 and a pair of slots 10 substantially parallel to the longitudinal axis of the segment 1.

The openings of each slot 10 are each bent so that a small force needs to be applied to the lugs 6 in order to allow the lugs 6 to pass through the openings by slightly bending the jaws of each slot 10. It is formed slightly narrower than the width of 6). Thereafter, each slot 10 is slightly widened beyond its opening to accommodate each lug 6 upon sliding.

In use, the lugs 6 of adjacent segments can be slotted into the slot 10 to seat the balls 5 in the socket 9 to form a ball-socket joint.

It is apparent that the female part 3 is laterally wider than the male part 2, which should have a size that can fit into the female part 3. Therefore, the outer surface of the female part 3 is more easily in contact with the inner wall of the catheter into which the segment 1 is inserted, and for this reason, the outer wall 8 of the female part 3 is in contact with the inner wall of the shell even when the bending angle is excessive. It should be curved to provide a smooth surface to support.

The lumen (not shown) is provided along the longitudinal axis of the segment 1 at or near the center, thereby allowing the guide wiring and the surrounding structure to pass through.

Two cutout channels 7 are provided on the outer wall of the female part 3 of the segment 1 so that other guide wires or similar structures can be used.

4, the lugs 6 of the segment 12 are fully inserted into the slots 10 of the segment 1 and the balls 5 (not shown) of the segment 12 have a socket 9 of the segment 1. Two identical segments 1, 12 seated within (not shown) are shown connected.

It can be seen from FIG. 4 that the width of the neck 4 is smaller than the inner diameter of the inlet of the socket joint 9, thus providing sufficient space for the segment 12 to rotate about the axis of the lug 6. Allow segment angle between (1) and segment (12). In FIG. 4, the segments 1, 12 are shown in a fully bent state, in which the segment 12 is such that the outer surface of the neck 4 of the segment 12 abuts the lip 11 of the segment 1. It is rotated about 15 degrees.

In use, between 15 and 80 segments are connected as shown in FIG. 4, the number of which depends on the length of the catheter into which the device is inserted. A medical implant is mounted on the end segment, and the end segment can be modified to receive the implant. A modified segment with handles is used at the end of the device away from the implant, with both handles applying force to the device along the longitudinal axis of the device (rotating the implant through the catheter) and rotating the implant. It is used to rotate the device about its longitudinal axis to apply a torsional force. This torsional force can be applied along the length of the device because there is no play between the lug 6 and the slot 10 of the adjacent segment.

For example, in order to implant the artificial vascular stent in vivo, the artificial vascular stent is mounted on one end of the device according to the invention and then inserted into the envelope and advanced until the artificial vascular stent is positioned at the end of the envelope remote from the operator. do. Thereafter, the envelope itself can be advanced under the catheter, which is inserted into the vascular system. Once the distal end of the envelope is at the target implant site, the envelope is slowly pulled back with the artificial vascular stent held in place by the device of the present invention. The operator can easily rotate the artificial vessel stent to accurately position the artificial vessel stent by rotating the handle at the end of the device. Also, unlike the device according to the prior art, the pressure applied to the sheath to deploy the artificial vessel stent does not compress the device. Thus, the device according to the present invention can be successfully used to implant artificial vascular stents in vivo.

Claims (16)

A segmental device for advancing a medical implant along a catheter, A medical implant mounted at one end of the device, comprising a plurality of segments arranged side by side, each segment hingedly connected to one adjacent segment if at the end of the column, otherwise connected to two adjacent segments Water can be advanced through the catheter by pushing the other end of the device, wherein the hinged connection allows the device to move along a curved path through the catheter. 2. The segmentation device of claim 1, wherein each segment is separable from its adjacent segment. 3. The segment of claim 1 or 2, wherein each segment comprises a male portion and a female portion, wherein the male portion of either segment can engage the female portion of the adjacent segment and the female portion can engage the male portion of the adjacent segment. Segmental device, characterized in that. 4. The articulation device according to claim 3, wherein the male portion includes a pair of protrusions and the female portion includes a slot for receiving the protrusion. 5. The articulation device according to claim 3 or 4, wherein the male portion comprises a ball and the female portion comprises a socket. The segmental device of claim 1, wherein the segment is formed of a material having sufficient rigidity to allow a moment of at least 1 Nm to be transmitted through the device. Segmentation device according to any one of the preceding claims, comprising 15 to 80 segments. 12. The segment of any one of the preceding claims, wherein each segment has a lumen through its body along the longitudinal axis of the segment such that when the device is in use, the plurality of lumens are substantially aligned so that the guide lead can pass therethrough. Segmentation device. The segmental device of claim 1, wherein each segment has a channel provided on its outer wall such that the plurality of channels are substantially aligned so that the guide leads can pass when the device is in use. The segmental device of claim 1, wherein the ratio of length to maximum diameter of each segment is in the range of 1: 1 to 1: 5. The segmentation apparatus of claim 1, wherein the maximum segment angle between the longitudinal axis of one segment and the longitudinal axis of an adjacent segment is at least 15 °. A kit comprising a device according to any one of the preceding claims and a medical implant mounted on one end of the device. The kit of claim 12, wherein the medical implant is a vascular graft tissue. The kit of claim 12 or 13, further comprising a delivery catheter. Segment for an apparatus according to any one of the preceding claims. A method of advancing a medical implant along a catheter, Providing an apparatus according to any one of claims 1 to 11 with an implant mounted on one end, Inserting the end of the device into the catheter; Extruding on the other end of the device.

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