Abstract:
A complex coil and a fixture for forming same configured such that loops are formed having various configurations relative to each other. The configurations provide improved thrombus formation and reduced rotation or tumbling once implanted. The complex coil is formed of a material that may deformed for purposes of placing the complex coil into a catheter and returns to a complex shape that includes said loops once deployed.

Description:
CROSS-REFERENCE TO RELATED DOCUMENTS 
     This application claims priority from, and incorporates by reference herein in their entireties U.S. Provisional Patent Application Ser. No. 60/738,087, filed Nov. 17, 2005, by Monetti et al. entitled Three Dimensional Complex Coil and U.S. Provisional Patent Application Ser. No. 60/822,656, filed Aug. 17, 2006, by Monetti et al. entitled Three Dimensional Complex Coil. 
    
    
     BACKGROUND OF THE INVENTION 
     The prior art contemplates a number of methods and devices for treating a body aneurysm using three-dimensional (3-D) shaped coils, sometimes referred to as “complex” coils. For example, Horton U.S. Pat. No. 5,766,219, the contents of which are incorporated by reference, shows a hollow structure. Phelps U.S. Pat. No. 5,382,259 and Ritchart U.S. Pat. No. 4,994,069, the contents of which are incorporated by reference, show other 3-D coil designs. Teoh U.S. Pat. No. 6,635,069, the contents of which are incorporated by reference, teaches a series of non-overlapping loops. Wallace U.S. Pat. No. 6,860,893, the contents of which are incorporated by reference, shows complex coils. Ferrera U.S. Pat. No. 6,638,291, the contents of which are incorporated by reference, shows a device similar to Teoh&#39;s and Wallace&#39;s except that a J-shaped proximal segment extends away from the complex portion of the device. 
     The following patents provide further background and are also incorporated herein by reference: Guglielmi U.S. Pat. No. 6,010,498; Gandhi U.S. Pat. No. 6,478,773; Schaefer 2002/0107534; Mariant U.S. Pat. No. 5,957,948; Pham U.S. Pat. No. 5,911,731; Lahille U.S. Pat. No. 4,957,501; Porter 2005/0192618; Wallace 2005/0192621. 
     There is, however an ongoing need to provide more advanced and improved complex coils so as to provide better treatment of an aneurysm. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide improved devices and methods for treating an aneurysm over the prior art. 
     This object and other objects not specifically enumerated here are addressed by the invention, at least one embodiment of which includes a toroid-shaped device wound around a fixture such that portions of the device&#39;s length meet or overlap in the center of the toroid. This allows the outer portion of the device to form a scaffold while the interior portion of the device provides occlusion to prevent the influx of blood and promote thrombus formation. 
     One embodiment includes a strand of material that self-forms into a toroid-shaped series of loops and is designed to provide a stable structure within the body cavity, allowing for occlusion of the cavity and serving as a framework to hold additional treatment devices. 
     Another embodiment of the present invention provides a strand of material that self-forms into a cruciform series of loops and is designed to provide a stable structure within the body cavity, allowing for occlusion of the cavity and serving as a framework to hold additional treatment devices. 
     In another aspect, the invention includes tools and methods of manufacture to make the aforementioned embodiments of the invention. 
     In yet another aspect of the present invention, an embodiment includes a cruciform device wound around a fixture comprising at least two parallel pins disposed at an angle to at least one additional pin. This construction allows the outer portion of the device to form a scaffold while the interior portion of the device provides occlusion to prevent the influx of blood and promote thrombus formation. This embodiment also advantageously resists rotating or tumbling during deployment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a fixture and a complex coil of the present invention; 
         FIG. 2  is a perspective view of an embodiment of a complex coil of the present invention; 
         FIG. 3  is a perspective view of an embodiment of a fixture and a complex coil of the present invention; 
         FIG. 4  is a perspective view of a complex coil of the present invention; 
         FIGS. 5-8  are photographs of a complex coils around various fixtures of the present invention; 
         FIGS. 9-10  are photographs of complex coils formed according to one of the methods of the present invention; 
         FIG. 11  is a perspective view of an embodiment of a complex coil of the present invention formed around an embodiment of a fixture of the present invention shown in phantom lines; 
         FIG. 12  is a perspective view of an embodiment of a complex coil of the present invention; 
         FIG. 13  is a perspective view of an embodiment of a complex coil of the present invention; 
         FIG. 14  is a perspective view of an embodiment of a fixture of the present invention; 
         FIG. 15  is a front elevation of the fixture shown in  FIG. 14 ; and, 
         FIGS. 16-19  are photographs of several complex coils formed using methods and fixtures according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Toroid Three-Dimensional Coil 
     Referring now to the figures and first to  FIGS. 1-6 , a coil or complex coil  10  is described that is shaped using a toroid-shaped fixture  12 . The coil  10  has been wrapped around the fixture  12  four times in  FIG. 1  such that four loops  14  are formed, each loop being positioned approximately 90 degrees from the adjacent loops. Wrapping the coil  10  around the fixture  12  causes the coil  10  to form into a complex shape when deployed into a body cavity such as a blood vessel or aneurysm. The device may be made from a length of wire that has been helically wound to form an elongate coil wire. Alternatively, the wire may be braided or knitted by methods known in the art to form a secondary shape. The wire is preferably a memory metal, such as Nitinol, but may be platinum, tantalum, tungsten, stainless steel, or other biocompatible material. Other materials, such as Dacron or Nylon fibers, biodegradable polymers such as polylactic or polyglycolic acid, and expansible or non-expansible hydrogel materials may be placed inside or outside the coil or braid structure to enhance the performance of the device. 
     For purposes of description only, an observation may be made regarding the shape of the complex coil  10  that results from wrapping the coiled wire around the toroid-shaped fixture  12 . As illustrated in  FIG. 2 , each of the loops  14   a - d  is roughly contained within respective planes  16   a - d . The planes intersect with each other at approximately a common intersection axis  18  near the center of the complex coil  10 . As one skilled in the art will realize, any loops formed around the toroid fixture  12  will only approximately be contained within such planes and the degree to which they are contained within these planes is only a function of how they are wound around the toroid and has little or no effect on their performance. 
     As shown in  FIGS. 3 and 4 , any number of loops may be used in forming a complex coil of the present invention. In  FIG. 3 , a complex coil  20  is formed by wrapping eight loops  22  around the toroid-shaped fixture  12 . The loops  22  are relatively evenly spaced around the toroid  12  but may be spaced in any number of configurations. The result is the eight-looped complex coil  20  shown in  FIG. 4 . 
       FIGS. 5 and 6  show complex coils  30  being formed around a toroid fixture  12  using  16  loops  32 . The loops  32  are grouped in sets of two such that only eight distinct loops appear. 
     One example used to treat conditions, such as cerebral aneurysms, includes a platinum/tungsten alloy complex coil (92% Pt, 8% W available from Sigmund Cohn Mount Vernon, N.Y.) with a diameter in the range of about 0.125 mm to about 0.625 mm and a length of about 5 mm to about 1000 mm. The complex coil is formed around a ceramic or metallic toroid-shaped fixture similar to the fixtures  12  shown in  FIGS. 1 ,  3 ,  5 , and  6 . The winding pattern shown in  FIGS. 1-2  forms a first loop  14   a  around the toroid  12 , then a second loop  14   b  approximately 180° around the toroid from the first loop. In this example, a figure 8 pattern is used to wind the first and second loops. A third loop  14   c  is then formed at an angle around the center of the toroid, typically 5° to 175°, to the second loop. A fourth loop  14   d  is formed using a figure 8 pattern from the third loop  14   c . More loops  14  may be added depending on the desired device size. 
     Those skilled in the art will appreciate that one advantage to the toroid complex coil configuration is that it may be scaled to the size of the treatment site by changing the number of loops. For example, very small (0.5-3 mm) lesions may be treated with 2 to 4 loop configurations, medium sized (4-10 mm) with 4-12 loop configurations, large (over 10 mm) with 8-36 loop configurations, and so on. The loops can form a closed structure such as an “O” shape (e.g. circle, oval, square, ellipse, star, etc.) or can be open such as a “C” or “U” shape. The loops may be of any dimension and are typically scaled to the approximate size of the treatment site. In the previous example, the loops may range from 0.5 mm diameter to 50 mm diameter. In this regard, “diameter” should not be narrowly construed to imply a circular dimension. Rather, “diameter” is used broadly to encompass the approximate size and shape of a loop. 
     After winding, the fixture and complex coil are heat-set by methods known in the art. For example, a typical annealing step for platinum complex coils is approximately 1100° F. for 5-40 minutes. 
     Once annealed, the complex coil will approximately retain the wound shape when substantially unconstrained or in its minimum energy state. The complex coil may then be subject to further processing such as forming a tip, adding a coupling mechanism for attachment to a delivery system, placing hydrogel or fibers onto or within the complex coil, placing a stretch resistant member inside or outside the complex coil, etc. The complex coil can then be attached to a delivery system, which is well known in the art, such as those disclosed in U.S. patent application Ser. No. 11/212,830, entitled Thermal Detachment System for Implantable Devices, the entirety of which is incorporated by reference hererin. Other examples of delivery systems are disclosed in Guglielmi U.S. Pat. No. 6,010,498 or Gandhi U.S. Pat. No. 6,478,773. Once attached to the delivery pusher, the complex coil is placed in a substantially linear configuration within a tube for delivery to the treatment site. 
     In a typical procedure, the linear complex coil is fed through a conduit such as a microcatheter by advancing it through the conduit with the delivery pusher. Upon exiting the microcatheter, the complex coil then self-forms into a structure within the treatment site that approximates its annealed shape. 
     The fixture  12  used to create the implant is shown as a closed circular toroid. However, other non-circular shapes such as elliptical, square, and star-shaped patterns may be used. In addition, the toroid does not need to be a closed structure. In fact, it may be easier to wind if a gap is left within the structure so that tension can be kept on the complex coil by hanging a weight. 
     Cruciform Three-Dimensional Coil 
     Referring now to  FIGS. 7-12 , the production of complex coils  40  are shown using a fixture  42  that includes a plurality of pins  44  arranged at right angles to each other. Like the embodiments shown in  FIGS. 1-6 , the embodiments of the complex coils  40  formed using the fixture  42  in  FIGS. 7-12  may be made from a length of wire that has been helically wound to form a coiled wire. Alternatively, the wire may be braided or knitted by methods known in the art to form a secondary shape. The wire may be platinum, tantalum, tungsten, stainless steel, Nitinol, or other biocompatible material. Other materials, such as Dacron or Nylon fibers, biodegradable polymers such as polylactic or polyglycolic acid, and expansible or non-expansible hydrogel materials may be placed inside or outside the complex coil or braid structure to enhance the performance of the device. By way of example only, one embodiment might be used to treat such conditions as cerebral aneurysms, employs a platinum/tungsten alloy complex coil  10  (92% PT, 8% W available from Sigmund Cohn Mount Vernon, N.Y.) with a diameter in the range of about 0.125 mm to about 0.625 mm and a length of about 5 mm to about 1000 mm. 
     The complex coil  40  is formed by wrapping a coiled wire around the fixture  42 , as shown in  FIGS. 7-8 . The fixture  42  is preferably a ceramic or metallic cruciform fixture and includes a plurality of pins  44  arranged at right angles to each other along axes x, y, and z. More specifically, the fixture  42  includes two pins  44   x  that are parallel to the x-axis, two pins  44   y  that are parallel to the y-axis, and two pins  44   z  that are parallel to the z-axis. 
     An example of a complex coil  40  that can be made using the fixture  42  of  FIGS. 7-8  is shown in  FIGS. 9-12 . The winding pattern in this embodiment, shown most clearly in  FIGS. 11-12 , forms a first loop  46   a  around a first pin  44   y   1 , then a second loop  46   b  around a second pin  44   x   1  that is disposed at an angle to the first pin  44   y   1 . In this embodiment the angle between the loops  46   a  and  46   b  is approximately 45°-135°. A third loop  46   c  is then formed in approximately the same plane as the second loop  46   b . In this example, the third loop  46   c  is formed around pin  44   x   2  in a figure 8 pattern with the second loop  46   b . A fourth loop  46   d  is then formed at an angle with the third loop  46   c . In this example, the fourth loop  46   d  is approximately 45°-135° to the third loop and is formed around pin  44   y   2  and is also approximately coplanar to the first loop  46   a . A fifth loop  46   e  is then formed at an angle to the fourth loop  46   d  by wrapping the wire around pin  44   x   1  spaced apart from loop  46   b , also formed around pin  44   x   1 . A sixth loop  46   f  lies in approximately the same plane as the fifth loop  46   e  in a figure 8 pattern with the fifth loop  46   e . The sixth loop  46   f  is formed by wrapping the wire around pin  44   x   2  spaced apart from loop  46   c , which is also formed around pin  44   x   2 . In this example, the fifth loop  46   e  and the sixth loop  46   f  are approximately concentric with the second loop  46   b  and the third loop  46   c , respectively. 
     Fewer than six loops may be used to form shorter complex coils, while additional loops may be wound to make a longer device. For example, the pins  44   z  shown in  FIGS. 7-8  extend through the pins  44   x  and  44   y  and are thus being used to hold the pins  44   x  and  44   y  in place. However, if a longer device is desired, loops could be formed by wrapping wire around the portions of the pins  44   z  extending from the pins  44   y.    
     Furthermore, those skilled in the art will appreciate that the same final result could be obtained by reversing the just-described winding pattern: i.e. winding a first loop around a first pin, winding a second loop in approximately the same plane as the first loop, winding a third loop at an angle to the second loop, winding a fourth loop at an angle to the third loop, winding a fifth loop in approximately the same plane as the fourth loop, winding a sixth loop at an angle to the fifth loop, and so on. 
     The loops can form a closed structure such as an “O” shape (e.g. circle, oval, square, ellipse, star, etc.) or can be open such as a “C” or “U” shape. The loops may be of any dimension and are typically scaled to the approximate size of the treatment site. In the previous example, the loops may range from 0.5 mm diameter to 50 mm diameter. In this regard, “diameter” should not be narrowly construed to imply a circular dimension. Rather, diameter is used broadly to encompass the approximate size and shape of a loop. 
     For example, the coil  50  shown in  FIG. 13  has loops  52  that are open and closed. The open loops are formed by wrapping a wire around a pin but transitioning to an adjacent pin prior to completing an overlapping loop. More specifically, the complex coil  50  of  FIG. 13  has six loops  52   a - f  formed using the fixture  42  of  FIGS. 7 and 8 . Loop  52   a  is a complete loop formed around one of the pins  44   y . The wire is then wrapped in a figure 8 pattern around two adjacent pins  44   x  to form open loops  52   b  and  52   c . The wire is next wrapped completely around the other y pin,  44   y  to form complete loop  52   d . Next, the wire is wrapped in a figure 8 pattern around the two pins  44   y  on the opposite side of pins  44   x  to form loops  52   e  and  52   f . The loop  52   e  is open but the loop  52   f  is closed, being the last loop. 
     Further complexity may be introduced using the fixture  60  shown in  FIGS. 14-15 . The fixture  60  in  FIGS. 14-15  also has a plurality of pins  62  but differs from the fixture  42  in  FIGS. 7 and 8  in three substantive ways. First, the pins  62  extend in directions parallel with x- and y-axes, but there are no pins that extend parallel to a z-axis. Rather, rectangular blocks  64  extend along the z-axis. Second, there are only two concentric pins,  62   x   1  and  62   x   2  that extend parallel to the x-axis. Third, there are four pins  62   y   1-4 , each having independent longitudinal axes. Winding using the fixture  60  results in complex coils  70  such as those shown in  FIGS. 16-19 . These figures show a complex coil  70  with first and second loops,  74   a  and  74   b , that are substantially coplanar and arranged in a figure 8 pattern, as well as third and forth loops,  74   c  and  74   d  that are similarly substantially coplanar and arranged in a figure 8 pattern that is rotated from the figure 8 pattern of the first and second loops,  74   a  and  74   b . The examples shown in  FIGS. 16-19  show the two figure 8 patterns rotated 90 degrees relative to each other. Additionally, the complex coils  70  include fifth and sixth loops,  74   e  and  74   f , which are relatively concentric. 
     After winding, the fixture and complex coil are heat-set by methods known in the art. For example, a typical annealing step for platinum complex coils is approximately 1100° F. for 5-60 minutes. 
     Once annealed, the complex coil will approximately retain the wound shape when substantially in a minimal energy state. The complex coil may then be subject to further processing such as forming a tip, adding a coupling mechanism for attachment to a delivery system, placing hydrogel or fibers onto or within the complex coil, placing a stretch resistant member inside or outside the complex coil, etc. The complex coil can then be attached to a delivery system, which is well known in the art, such as those disclosed in U.S. patent application Ser. No. 11/212,830, entitled Thermal Detachment System for Implantable Devices, the entirety of which is incorporated by reference hererin. Other examples of delivery systems are disclosed in Guglielmi U.S. Pat. No. 6,010,498 or Gandhi U.S. Pat. No. 6,478,773. Once attached to the delivery pusher, the complex coil  10  is placed in a substantially linear configuration within a tube for delivery to the treatment site. 
     In the typical procedure, the linear complex coil is fed through a conduit such as a microcatheter by advancing it through the conduit with the delivery pusher. Upon exiting the microcatheter, the complex coil then self-forms into a structure within the treatment site that approximates its annealed shape. 
     Although the invention has been described in terms of particular embodiments and applications, one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.