Vaso-occlusive coils with non-overlapping sections

<u style="single">Technical field to which the invention belongs</u> The present invention generally relates to vascular occlusion devices, in particular vascular occlusion implants having a primary shape of a spiral coil and a secondary shape with non-overlapping portions.

<u style="single">Background of the invention</u> A vascular occlusion device is an implant placed in a cavity within a patient's vascular structure, for example, within an aneurysm located in the vascular structure of the brain. The device is usually implanted with a delivery catheter that advances through the cavity to the treatment site.

An example of a well-known vaso-occlusive device is a "primary shape" that, when confined within a delivery catheter, is wound into an elongated spiral and is slightly opened at the implant site, which remains unfolded from the catheter. , Has a three-dimensional "secondary shape". Due to their helical primary shape, these devices are commonly referred to as vascular obstruction devices. The coil is typically made of a very flexible and flexible metal, such as a platinum alloy. Depending on the size and / or shape of the aneurysm, one or more occlusion coils are implanted to reduce the risk of the aneurysm growing and / or rupturing. The vascular occlusion coil also promotes embolization of the aneurysm.

In order to manufacture a vascular occlusion coil, first, a wire made of a coil material is wound around a first mandrel having a small diameter and heated to form a spiral primary shape. Next, this primary shape coil is wound around a second mandrel having a larger diameter, heated, and the secondary shape is set in the primary shape coil.

One drawback of this process is that when winding the primary coil over or around the secondary mandrel, the secondary windings (larger loops formed by the elongated primary coil) often overlap each other. Is. In particular, overlapping windings around the secondary mandrel can result in kinks and sharp bends in the coil that can be "programmed" into the secondary shape of the coil during the heat treatment. These twists and bends increase the frictional resistance of the coil as it advances through the delivery catheter, requiring more force to deploy the coil into the aneurysm cavity. Twisting and bending also cause problems when a partially unfolded coil needs to be removed from the body, as it is easily entangled with another unfolded coil at that site. In addition, the non-uniform or overlapping secondary windings cause the coil to stress the aneurysm wall more, increasing the chances of the aneurysm wall being damaged or destroyed.

<u style="single">Outline of the invention</u> According to one embodiment, the vascular obstruction coil comprises an elongated, spiral primary shape that defines the spindle and a three-dimensional secondary shape that has a nearly spiral first and second section. .. The second section has multiple non-overlapping loops. Each loop defines a surface along the main axis that makes an angle of about 30 to about 150 degrees with respect to the surface defined by the immediately preceding or immediately following loop.

According to another embodiment, the vascular obstruction coil has a nearly spiral primary shape that defines the spindle, and this primary shape is wound into a three-dimensional secondary shape. The secondary shape comprises a nearly spiral first section and a second section that immediately follows this first section along the main axis. The second section has multiple non-overlapping loops. This loop comprises a first loop, a second loop that immediately follows the first loop along the main axis, and a third loop that immediately follows the second loop along the main axis. The first loop defines a surface that forms an angle of at least about 30 degrees with respect to the surface defined by the second loop. The second loop defines a surface that forms an angle of at least about 30 degrees with respect to the surface defined by the third loop.

<u style="single">Detailed description of the examples</u> In the following description, the accompanying drawings are referred to, which illustrate a special embodiment of the present invention. It should be understood that other examples are also available.

Generally, a vascular obstruction coil is made by winding an elongated coil with a spiral primary shape to define a spindle around a secondary mandrel. The secondary mandrel and the wound primary shape coil are heated to program or set the 3D secondary shape. The secondary shape has a nearly spiral first section and a second section with multiple non-overlapping loops. The coil also has a smooth surface. Each loop defines a plane along the main axis that is oriented at an angle (eg, 30-150 degrees) with respect to the plane defined by the immediately preceding or immediately preceding loop.

In particular, referring to FIG. 1, the wire or coil material 100 is processed into a primary structure or shape 110 that defines the spindle 120. The primary coil shape 110 may be an elongated spiral primary coil shape, and can be set by using a known manufacturing method. The axial length of the coil material 100 having the primary shape 110 may be, for example, between about 0.5 and 100 cm, preferably between about 2 and 40 cm. The primary coil shape 110 is, for example, about 10 to 75 turns per cm, preferably 10 to 40 turns per cm. The coil material 100 having the primary shape 110 is further processed to take a secondary shape.

With reference to FIG. 2, after the primary shape 110 is set, the primary shape 110 coil can be wound around the secondary mandrel 200. The coil of the primary shape 110 wound with the secondary mandrel 200 can be heat treated to form or be programmed into the primary shape 110 coil having the secondary shape 210.

An exemplary secondary mandrel 200 has a shaft 220 and one or more posts 230a-d (generally 230). The post 230 can extend from the shaft 220 in various angles and directions. The "post" may be the "shaft" and the "shaft" may be the "post" by repositioning the secondary mandrel 200. However, for illustration and illustration, this specification sets a reference point by referring to "shaft" 220 to one or more "posts" 230.

The secondary mandrel 200 can be made of a variety of known materials that can be heated during the manufacture of the coil, eg, when the coil material or wire 100 is heat treated. Exemplary secondary mandrel 200 materials include, but are not limited to, ceramics, or other heat resistant materials, including alumina or zirconia.

The secondary mandrel 200 provides a support around which the primary shape 110 coil is wound, and also provides a particular secondary shape 210 when heating the secondary mandrel 200 and the primary shape 110 coil. For example, a primary shape 110 coil material made of a platinum / tungsten alloy and wound around a secondary mandrel 200 is heated to about 1100 degrees Fahrenheit for about 15-20 minutes to program the secondary shape 210, or Can be set.

The heating temperature and duration will vary for different materials. For example, the heating temperature and duration are not made entirely of metal and can be lowered when heating coil materials containing, for example, one or more metal components and non-metal components such as molten plastics.

The primary shape 110 coil can be wound around the shaft 220 and / or the post 230 one or more times at various angles to form the secondary shape 210 coil. As shown in FIG. 2, the secondary shape 210 has two sections, a substantially spiral first section 211 and a second section 212. The Hobonichi first section 211 is formed around the shaft 230. The second section 212 is formed on top of the first section 211, around one or more posts 230. In the illustrated embodiment, the first section 211 is below the second section 212, but the first section 211 can also be formed above the second section 212.

The first section 211 comprises a plurality of spiral windings wound around the post 220. The second section 212 has a plurality of non-overlapping loops. Each loop in Section 212 defines a plane along the spindle 120 that is angled (30-150 degrees) with respect to the plane defined by the immediately preceding or immediately following loop. The angle between the faces defined by this loop varies depending on the number and placement of posts 220 in the secondary mandrel 200.

The primary shape 110 coil can be wound around the shaft 220 and / or one or more posts 230 at various angles. For example, depending on the required secondary coil shape 210 and the number and placement of non-overlapping loops, the angles are less than about 360 °, no more than 270 °, and no more than 180 °. After setting or programming the secondary shape 210, this shape can be cut from the secondary mandrel 200. For example, the secondary shape 210 coil can be cut between the first spiral section 211 and the second section or loop section 212, or at other locations as needed.

The sequence and pattern of the non-overlapping primary shape 110 coils wound over the secondary mandrel 200 will vary depending on the desired secondary shape 220. The primary shape 110 coil can be wound at various angles both above, below or above and below the post 230 or shaft 220. In some cases, the primary 110 coil is not wound over the shaft 220, only over some posts 230.

FIG. 3 is a diagram showing an alternative embodiment, in which the secondary shape 310 has three sections. A nearly spiral first section 311 is formed around the shaft 220, and a second or intermediate section 312 is formed around one or more posts 230 above the first section 311. A spiral third section 313 is formed over the second section 312 around the shaft 220. In this embodiment, a second or intermediate section 312 is formed around the post 230, between two nearly spiral sections 311 and 313. The secondary shape 310 coil can be cut between the first and second sections 311 and 312 and between the second and third sections 312 and 313 or at other positions as needed.

Figures 4 and 5 show exemplary loop structures in the second sections 212 and 312 (generally 212) of the secondary shapes 210 and 310 (generally 210). However, FIGS. 4 and 5 show a second section 212 that is separated from one or more of the above substantially spiral sections. Further, considering that the coil is flexible when a force is applied, FIGS. 4 and 5 show an initial, unforced, relaxed coil.

Referring to FIG. 4, one embodiment of the secondary shape 210 coil comprises a plurality of non-overlapping loops. This loop is generally smooth and has no sharp or twisted sections. In particular, this embodiment of second section 212 comprises five nearly circular loops or loop sections 410a-e (generally 410) defining each surface. The first loop 410a is directly connected to the second loop 410b. Loop 410b is directly connected to third loop 410c. Loop 410c is directly connected to fourth loop 410d. The loop 410d is directly connected to the fifth loop 410e. FIG. 5 is a diagram illustrating an example of an alternative second section 212, which includes six loops 510a-f defining each face. The loops in Figures 4 and 5 are shown to be approximately the same size and shape, but with shafts or posts of other sizes and / or smooth shapes, if desired, other sizes. And shapes can be used. Therefore, the secondary coil section 212 shown in FIGS. 4 and 5 is an example of other possible coils and winding patterns.

For example, coil loops or loop sections 410 and 510 (typically 410) of various lengths can be formed around the axis in the secondary shape 210. The loop of coil section 212 or loop section 410 can extend around the axis at less than about 360 °. For example, loop 410, shown in the figure, is a partial loop that typically has coil windings below about 360 °. Other angles of winding are also available. For example, less than 270 °, less than 180 °, and so on. In fact, different coil structures require different angles of winding around the secondary mandrel 200, forming different loops or loop section structures.

The relationship from one loop to the other loop of the second coil section 212 also varies depending on the special non-overlapping winding pattern and the secondary coil shape 210. For example, the individual adjacent loops 410 form faces oriented at various angles related to each other, for example, about 30 degrees or about 150 degrees. For example, an angle of about 30 degrees is the result of having more winding posts, and a larger angle is the result of using fewer posts.

As shown in the embodiment shown in the figure, each surface defined by the loop 410 of the second coil section 212 is substantially orthogonal to the surface defined by the adjacent loop. For example, in FIG. 4, the surface defined by loop 410a (coil side) is approximately orthogonal to the surface defined by loop 410b (coil front) and loop 410c (coil bottom). doing. Similarly, the planes defined by loops 410a and 410b are approximately parallel to the planes defined by loops 410d and 410e, respectively. Therefore, depending on the configuration of the windings and coils, the surfaces defined by the various numbers of loops may be approximately parallel to the opposite opposing surfaces and orthogonal to the adjacent surfaces. It may be at various angles depending on the specific structure.

Different numbers of loops make different coil shapes, and this loop can be made using different winding mechanisms. For example, the second coil section 212 may include various numbers of loops, such as loops of about 15 or less. FIG. 4 is a diagram showing a second coil section 212 having five loops or loop sections, and FIG. 5 is a diagram showing a second coil section having six loops or loop sections. Depending on the number of loops and / or non-overlapping coil patterns, the coil sections may or may not be in contact with each other. Further, as in the embodiment shown in the figure, the ends of the coils can be placed at various positions, for example, in opposite loops, in adjacent loops, in adjacent loops that are approximately orthogonal to each other, and so on. ..

Vascular obstruction coils with non-overlapping coil sections can be made of a variety of materials, depending on the particular application. For example, the coil may be made of metal, polymer, alloy, or a composite of these. The coil preferably comprises a material compatible with magnetic resonance imaging.

In addition, the coil may include a radiation opaque material such as metal, alloy, or polymer. Suitable metals and alloys for the wires defining the coil include tungsten, gold, silver, tantalum, and alloys of these metals, as well as platinum group metals, in particular platinum, rhodium, palladium, and renium. These materials have significant radiation impermeability and these alloys can be adjusted to combine flexibility and rigidity for the coil. These materials are also generally biologically inert. The platinum / tungsten alloy is most preferably accompanied by an iron material mixed with this alloy or an iron material carrying this alloy.

Alternatively or additionally, the coil may be a radiation permeable fiber such as Dacron (polyester), polyglycolic acid, polylactic acid, fluoropolymer (polytetrafluoroethylene), Nylon (polyamide) and / or silk. It may be composed of a polymer (or a metal thread coated with a radiation-permeable or radiation-impermeable fiber), or may be provided with this fiber or polymer. If the polymer is used as the main component of a vascular obstruction device, the device may be supplemented with some amount of radiation opaque material such as powdered tantalum, tungsten, bismuth oxide, barium sulfide and others. .. Further, iron materials such as iron particles, filaments, etc. may be mixed with the polymer and / or embedded in the polymer.

If the coil is made of a platinum alloy or a superelastic alloy such as nitinol, or any other material, the diameter of the wire defining the coil is approximately 0.0005 to 0.006 inches (0.012-0.15 mm). The wire may be wound around a primary coil having a primary diameter of about 0.005 to 0.035 inches (0.125-0.625 mm), preferably about 0.010 to 0.018 inches (0.25-0.45 mm). Such wires provide sufficient hoop strength and cause the vascular obstruction device to occur at appropriate locations within the selected body cavity, without inflating the walls of the cavity, and / or within the vasculature system. It is made of an appropriate diameter so as to hold it without substantially moving out of the cavity as a result of each liquid pulse.

In addition, various secondary mandrel 200 shapes can be used to make various secondary shapes 210. For example, FIG. 6 is a plan view of a secondary mandrel 600 having three posts 630a-c arranged in a "T" shape around a shaft 620. FIG. 7 is a plan view of the secondary mandrel 700, with three post groups 730a-c arranged in a triangle around the shaft 720. Thus, a group of posts can be arranged squarely or orthogonally (ie, Figure 2-3), T-shaped (eg, Figure 6), triangular (eg, Figure 7), and various diagonal shapes or needs. It can be offset shape accordingly. Thus, the figure generally means that all posts arranged in a crossing direction, various non-crossing directions, or offset directions with respect to the shaft can be used.

Other post groups and a plurality of post groups can also be used depending on a specific application. For example, 2, 5, 6, 7, 8, 8, 9, 10, and other numbers of posts can be used as needed. For purposes of illustration and without limitation, this specification is described primarily with reference to a secondary mandrel 200 having three or four posts extending from the shaft.

In addition to using different numbers of posts, other structures and orientations of the posts can be used for non-overlapping windings. Non-overlapping winding technology can be used with posts that have a smooth shape other than the general circular shape. For example, with reference to FIGS. 8 and 9, the shapes of smooth oval shafts 820, 920 and / or posts 830, 930 can be used. Other shapes such as trapezoidal, pear, dumbbell, and other smooth shapes can also be used as needed.

Further, for example, different sizes of shaft 220 and post 230 can be selected depending on the length of the coil material wrapped around the desired secondary coil shape 210 and secondary mandrel 200 in a non-overlapping manner. it can. For example, the shaft / post of one example is cylindrical and has a diameter of about 1 mm to 40 mm, preferably about 2 mm to 20 mm. Other post and shaft diameters and sizes can be used depending on the particular application and device to be made.

In use, the product has the coil confined within the primary shape 110 and is biased to take the three-dimensional secondary shape 210 in the relaxed state. Therefore, if the coil is not restricted by external force or barrier, the coil takes a relaxed, three-dimensional secondary shape 210. Further information on suitable methods for manufacturing vasculature devices can be found in US Pat. No. 6,322,576.

The coil takes its primary shape (elongated spiral coil) 110 when it is placed within the catheter or other delivery device used to deliver into the patient's body. As is well known in the past, catheters are generally introduced into the patient's body from a percutaneous portal site, for example into peripheral arteries such as the femoral or cervical arteries (not shown). To. The catheter may be advanced by placing it on a guide wire or other rail pre-located within the patient's vessel using a known method. The catheter is advanced through the patient's vessel until the distal end is placed in a blood vessel near the aneurysm.

When the catheter is placed correctly, a vascular occlusion coil in primary shape 110 is advanced into the aneurysm through the lumen of the catheter. When the vascular obstruction coil unfolds and expands or relaxes, it takes a three-dimensional secondary shape 210, as described above. Preferably, the secondary shape is selected such that the vascular occlusion coil substantially fills the aneurysm.

<figref num="1">FIG. 1 is a diagram showing a part of a coil material having an elongated spiral primary shape that generally defines a spindle.</figref><figref num="2">FIG. 2 is a diagram illustrating an embodiment of a vascular occlusion coil having a three-dimensional secondary shape, having a substantially spiral first section and a second section having a plurality of non-overlapping loops.</figref><figref num="3">FIG. 3 is a diagram illustrating an embodiment of a vascular obstruction coil having a substantially spiral first section, a second section having a plurality of non-overlapping loops, and a nearly spiral third section.</figref><figref num="4">FIG. 4 shows an example of a second or central section of a vascular obstruction coil with a secondary shape removed from the mandrel.</figref><figref num="5">FIG. 5 shows another embodiment of a second or central section of a vascular obstruction coil with a secondary shape removed from the mandrel.</figref><figref num="6">FIG. 6 is a plan view showing an alternative mandrel structure with three posts arranged in a T structure.</figref><figref num="7">FIG. 7 is a plan view showing another alternative mandrel structure with three posts arranged in a common triangle.</figref><figref num="8">FIG. 8 is a partial side view showing an alternative mandrel structure with an elliptical position.</figref><figref num="9">FIG. 9 is a partial side view showing another alternative mandrel structure with elliptical posts in different directions.</figref>