Patent ID: 12256932

For a thorough understanding of the present disclosure, reference should be made to the following detailed description, including the appended claims, in connection with the above-described drawings. Although the present disclosure is described in connection with exemplary embodiments, the disclosure is not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient.

DETAILED DESCRIPTION

The invention includes self-opening and self-closing polygonal magnetic devices that couple to each other with substantial compressive magnetic force. The invention makes it possible to create surgical anastomoses in tissue quickly with minimally-invasive techniques such as endoscopy and laparoscopy. Once the devices have are placed and mated, the compressive forces cause the vasculature of the tissue to collapse and fluids to extrude from the tissues, reducing the distance between the devices and increasing the magnetic attraction. With time, the coupled devices eventually mate completely, form an opening, and fall away from the tissue, leaving an anastomosis. The magnetic devices can, thus, be used to create surgical-quality anastomosis without the need to create an open surgical field.

With the described technique it is simpler to create openings between tissues that traditionally required open surgery or the use of complicated cutting and suturing devices. Most procedures are reduced to simply delivering a first magnetic compression device to a first tissue and then delivering a second magnetic compression device to a second tissue, and then bringing the two devices together. For example, it is straightforward to create a gastric bypass by delivering first and second magnetic devices, in the form of octagons, to the stomach and the small intestine. The magnetic force of the two devices eventually creates an anastomosis that leads from the stomach to the small intestine, reducing the working volume of the stomach.

The devices of the invention generally comprise magnetic segments that can assume a delivery conformation and a deployed configuration. The delivery configuration is typically linear so that the device can be delivered to a tissue via a laparoscopic “keyhole” incision or with delivery via a natural pathway, e.g., via the esophagus, with an endoscope or similar device. Additionally, the delivery conformation is typically somewhat flexible so that the device can be guided through various curves in the body. Once the device is delivered, the device will assume a deployed configuration of the desired shape and size by converting from the delivery configuration to the deployed configuration automatically. The self-conversion from the delivery configuration to the deployment configuration is directed by coupling structures that cause the magnetic segments to move in the desired way without intervention.

As shown inFIG.1two devices10and20are brought to opposite sides of tissues30and40, in which an anastomosis is to be formed. Once the two devices10and20are brought into proximity, the devices10and20mate and bring the tissues30and40together. With time, an anastomosis of the size and shape of the devices10and20will form and the devices will fall away from the tissue. Alternatively, because the mated devices10and20create enough compressive force to stop the blood flow to the tissues30and40trapped between the devices, a surgeon may create an anastomosis, by making an incision in the tissues30and40circumscribed by the devices. In yet another embodiment, a surgeon may first cut into the tissue, e.g., tissue30, and then deliver the device10around the incision and then couple the second device20to the first device so that the devices10and20circumscribes the incision. As before, once the devices mate, the blood flow to the incision is quickly cut off. The mating device20may be delivered in the same way, e.g., through an incision, or the mating device20can be delivered via a different surgical route, e.g., via an endoscope.

During the procedure, the position of the two devices10and20can be visualized directly, e.g., using an endoscopic or laparoscopic camera. In other instances, the two devices10and20can be monitored with ultrasound or another medical imaging technique, such as fluoroscopy. In some embodiments, the visualization will be provided with the delivery device. In some embodiments, the visualization will be achieved with a separate device. Other techniques, known in the art, such as dyes, contrast, and gas delivery may also be used to assist visualization of the mating devices.

As described in greater detail below, the design of the devices10and20can be customized depending upon the surgical techniques that will be used and the specific needs of the patient. The design specifications may include: required capture range, desired effective inner and outer diameters of the magnetic device (e.g., as defined by the desired anastomosis size and instrument passage), thickness of the target tissue, and the inner diameter of the guiding channel and the smallest radius of curvature to which the guiding channel may be bent and through which the magnets must pass. Once the design specifications are chosen, corresponding magnetic device designs can be determined, such as polygon-side-count and length, and the maximum lateral dimensions of the flexible linear magnetic structure that will be deployed through the delivery instrument. Additionally, as described below, the arrangements of the magnetic segments that make up the device may be altered to customize the amount of force between the devices10and20at a distance, e.g., at 1 cm or further apart.

Using the techniques outlined above, it is possible to create anastomoses between a variety of tissues and organs in the gastrointestinal tract, as depicted inFIG.2. For example, anastomoses may be formed between the stomach, small intestine, gall bladder, and colon, as shown inFIG.2. Such techniques can be used for management of disease, such as obesity and diabetes, or such techniques can be used to improve function in the wake of disease, such as cancer. Such techniques can also be used for repair, for example, to connect portions of healthy colon after a portion of diseased colon has been removed. Such procedures can be accomplished endoscopically, laparoscopically, with an open surgical field, or with some combination of these techniques.

A device of the invention, generally, includes a plurality of magnetic segments that assume the shape of a polygon once deployed in a patient. The magnetic segments are typically formed from rare earth magnets. The magnetic segments may be mitered. The magnetic segments may be coated with gold or plastic to improve their performance. A general depiction of an octagonal device is shown inFIG.3, however it is to be understood that a variety of deployed shapes are feasible using the same construction, such as squares, hexagons, decagons, dodecagons, tetradecagons, hexadecagons, octodecagons, and icosagons. As shown inFIG.3, each magnetic segment of the device has at least at least two poles, north “N” and south “S,” with the poles oriented normal to the face of the polygon. For convention, the north magnetic poles of the segments of the application are sometimes cross-hatched, while the south magnetic poles are solid (or not cross-hatched). As shown inFIG.3, an out of plane axis can be defined that runs through the center of the polygon and normal to the face of the polygon, defining a “TOP” and a “BOTTOM” of the device. (It is understood that “TOP” and “BOTTOM” are arbitrary, but correspond to different sides of the polygon.)

Because each magnetic segment has at least one north pole and at least one south pole, it is possible to create devices of the invention with a variety of magnetic polar configurations. For example, the device shown inFIG.3includes four magnetic segments arranged toward the top of the polygon, and four magnetic segments arranged toward the bottom of the polygon. Furthermore, as show inFIG.3, the four magnetic segments arranged toward the top of the polygon are all adjacent each other. Such a configuration may be written N/N/N/N/S/S/S/S or NNNNSSSS, or N4/S4. Other arrangements of the magnetic poles are possible in an octagonal device, such as shown inFIG.4. For example, all of the poles can be arranged in the same direction, i.e., N/N/N/N/N/N/N/N or N8 (top left ofFIG.4), or the magnetic poles can be alternated in each segment. i.e., N/S/N/S/N/S/N/S or NSNSNSNS (bottom ofFIG.4). Other configurations of the magnetic poles are also available, such as N/S/N/SS/N/S/N or N2SNS2NS, or N/SS/NN/SS/N or N2S2N2S2, or NN/SSSS/NN or N2S4N2, all shown inFIG.4.

The variety in magnetic polar configuration can be extended to other geometries with fewer or greater numbers of magnetic segments. For example, as shown inFIG.5, a device with 12 segments can be arranged with N12, N6S6, N3S3N3S3, N2SNSNS2NSNS, N2SN2S4N2S, or NSNSNSNSNSNS. Of course, the mirror images are also possible, such as S2NS2N4S2N, however such configurations are actually identical when viewed from the other side. The same principles can be used for devices that have fewer segments, for example, four segments (N4, N2S2, and NSNS), or six segments (N6, N3S3, N2S2NS, and NSNSNS). The same principles can be used for devices that include more than twelve segments, for example, sixteen segments (N16, N8S8, N6SNS6NS, N4S4N4S4, N4S2N2S4N2S2, N4SNSNS4NSNS, N3SN3SNS3NS3, N2S2N2S2N2S2N2S2, N2S2NSNSN2S2N2S2, N2S2NSN2S2NSN2S2, and NSNSNSNSNSNSNSNS).

The benefits of differing magnetic polar configurations are illustrated inFIG.6. As depicted in the graph ofFIG.6, the relative attractive force between two octagons of identical magnetic polar configuration, as the devices are brought closer together, is a function of magnetic polar configuration. However, the total attractive force when devices of the same number of segments are brought into contact should be roughly the same. (The units on both axes are arbitrary, as is the variation between the curves.) In general, two devices having the magnetic poles of all of the magnetic segments arranged in the same direction with respect to top of the polygon experience the greatest amount of magnetic attraction at a distance (N8; solid line), while two devices having alternating magnetic poles in the magnetic segments have the least amount of magnetic attraction at a distance (NSNSNSNS; dot-dashed line). Intermediate to these two extremes are configurations in which the similarly-aligned magnetic segments are next to each other but not all poles are arranged in the same direction, i.e., N4S4 (long dashed line) and staggered configurations such as N2SNS2NS (short dashed line). Other configurations, not shown in the graph ofFIG.6, such as N7S, N5SNS, etc., would also have curves somewhere between the N8 curve and the NSNSNSNS curve.FIG.7shows actual force measurements made by securing magnetic arrangements in epoxy and bringing them toward each other with a dynamometer. As can be seen inFIG.7, there is marginal difference in force at a distance between N8 and N4S4 octagons. It should be noted that, as shown inFIG.7, there is a wide variation of force at a distance of approximately 1 cm (10 mm).

Accordingly, by selecting a particular configuration, a surgeon can “tune” the interaction between devices for the desired performance. Thus, if it is necessary to maximize force at a distance to facilitate bringing tissues together, a surgeon can use two devices with all of the poles arranged in the same direction, i.e., N8. If, on the other hand, the placement of the devices was critical, and the surgeon wanted to minimize the chance that the devices mated before necessary, the surgeon could use a configuration with alternating magnetic poles, i.e., NSNSNSNS. In fact, for some procedures, it may be useful to provide a kit of matched devices with varying magnetic polar configurations, such as shown inFIG.8. Such a kit would allow a surgeon to choose a desired configuration during the procedure, based upon visualization of the surgical field after the procedure has started. Alternatively, such a kit could provide “back-up.” in the form of stronger-attracting devices, if the surgeon encountered difficulties joining the tissues during the procedure.

While not wishing to be limited by theory, it is believed that the variability between different magnetic polar configurations is a function of how much interaction a given magnetic pole has with segments of the same polarity on the mating device. That is, at intermediate distances, i.e., between no interaction and touching, each magnetic pole is interacting with multiple magnetic segments on the mating device. In the instance where mating devices comprise segments with alternating poles, a magnetic segment from a first device interacts with at least one opposite pole and two same poles on a nearby mating device. The same pole repulsions cancel out a good portion of the opposite pole attraction, resulting in less aggregate attraction at distances of about 1 cm or more. In the other extreme, a segment of a device having all of the poles arranged in the same direction would only experience attractive forces between it and the segments of the mating device.

Nonetheless, regardless of magnetic polar arrangements, once the two devices are brought together, most of the interaction is between a segment of the first device and the corresponding segment on the mating device. Accordingly, the total attractive force between devices of different configurations is about the same once the devices are joined.

In a similar fashion, devices of differing numbers of segments, i.e., squares, hexagons, octagons, decagons, dodecagons, tetradecagons, hexadecagons, octodecagons, and icosagons can be tuned by selecting particular arrangements of magnetic poles. There are also additional reasons that a particular configuration of magnetic poles may be chosen, for example, to cause the devices to overlap correctly, or to cause the devices to connect in a way that insures that the devices cannot revert to their delivery configuration. See e.g., US 2013/0253550, incorporated herein by reference in its entirety.

The variability in magnetic polar orientation, described above, can be used in a variety of deployable magnetic devices, including both self-opening and self-closing devices, as described below. For example, self-opening devices may be constructed having a variety of magnetic polar arrangements, as shown inFIGS.9A-10B. Additionally, self-closing devices may be constructed having a variety of magnetic polar arrangements, as shown inFIGS.12-15. As shown inFIGS.11and16, the two configurations (self-opening and self-closing) lend themselves to deployment with different methods, i.e., laparoscopy and endoscopy, respectively. Accordingly, various combinations of devices can be selected, as required, based upon the surgical approach, and the requirements of the anatomy of the patient.

In some embodiments of the invention, the deployable magnetic device is self-opening, i.e., as shown inFIGS.9A-10B. Each device comprises a number of magnetic segments810, wherein two pairs of magnetic segments are linked together at each end with a connection member830, such as a hinge. The magnetic segments810between the connection members830are linked together with additional connection members850, which are configured to direct the device to self-convert from a delivery870to a deployed890configuration. It should be noted that the term “connection member” may be used herein to refer to a hinge or a polygon-opening member, depending on the application. For example, connection member830may be referred to herein as a “hinge”, which connection member850may be referred to herein as a “polygon-opening member”.

While the polygon-opening members850are shown coupled to the exterior of the magnetic segments inFIGS.9A-10B, the polygon-opening members may also be coupled to the interior of the magnetic segments. In some instances, the polygon-opening members form an exoskeleton over the magnetic segments. The polygon-opening members may be bonded or fastened to the magnetic segments or the polygon-opening members can crimp or grab the magnetic segments.

While each self-opening device comprises two hinges, the number of polygon-opening members850depends upon the total number of magnetic segments in the device. For example, for a device that takes the configuration of a square upon deployment, the device will comprise four magnetic segments810, two hinges830, and two polygon-opening members850. As shown inFIGS.9A-10B, an octagonal self-opening device may include eight magnetic segments810, two hinges830, and six polygon-opening members850. In alternate embodiments, a singular polygon opening member may span two or more magnetic segments810(shown inFIG.10B). In alternative embodiments, as shown inFIG.9B, a quadrupolar magnetic segment can be used at the hinge end to improve opening. Quadrupolar segments are not limited to octagonal configurations, and can be used with any of the configurations described herein. Thus, it is possible to construct a self-opening octagonal device with eight magnetic segments810, two hinges830, and two polygon-opening members (seeFIG.10B). Using the same techniques it is possible to construct deployable self-opening devices having different numbers of magnetic segments that deploy as, e.g., squares, hexagons, decagons, dodecagons, tetradecagons, hexadecagons, octodecagons, or icosagons.

The self-opening devices of the invention can incorporate a variety of magnetic polar configurations, as shown inFIGS.9A-10B. However, because of the devices need to self-convert between a side-by-side arrangement and an open polygon, it is beneficial to place the hinges such that similarly-aligned magnetic poles are next to each other in the delivery configuration. For example, as shown inFIG.10A, each segment in the delivery configuration is next to a segment of the same magnetic orientation so that, upon delivery, the magnetic repulsions between segments drives the device into the open (deployed) configuration. In such a configuration, the primary role of the polygon-opening member is to insure that the device opens in the plane of the polygon; i.e., that out-of-plane motion of the magnetic segments is limited. The hinges of the self-opening devices may be constructed from metal (stainless steel, nickel, or nitinol) or plastic, and the hinges may be passive or active, i.e., configured to provide an opening force. In some instances, the hinges are springs. The polygon-opening members may be constructed from constructed from metal (stainless steel, nickel, or nitinol) or plastic. The polygon opening members are typically active in that they provide a force to drive the device from a delivery configuration to a deployment configuration.

An alternate construction of an eight segment, self-opening device of the invention is shown inFIG.10B. In the embodiment ofFIG.10B, only two polygon-opening members850are needed to direct the device to open properly. Like other self-opening devices, the device includes two hinges830that help the device transform from a delivery configuration (bottom left) to a deployed configuration (bottom right). The device shown inFIG.10Bmay be constructed by first coupling two pairs of magnetic segments810with hinges830, and then arranging the remaining magnetic segments810in a deployed configuration. Each polygon opening member850can then be coupled to four segments, including one segment of each hinged pair, to complete the assembly (top ofFIG.10B). The polygon opening members850may be bound, coupled, or attached to the magnetic segments. Alternatively, as shown inFIG.10B, the polygon opening members850may envelop the magnetic segments, e.g., as an exoskeleton. While it is not shown inFIG.10B, it is understood that the polarities of the magnetic segments810can be configured as desired to achieve specific performance at a distance, i.e., as discussed above with respect toFIGS.3-6. Additionally, the construction shown inFIG.10Bis not limited to eight magnetic segments, as a polygon-opening member850can be coupled to many magnetic segments, such as two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, or fifteen magnetic segments.

The self-opening devices of the invention are designed to be delivered in a side-by-side configuration as shown inFIG.11. In this configuration, a self-opening device can be inserted through a trocar1100or other cannula to a location within a patient where the device will be deployed and coupled to a mating device. Typically, a pusher1130will be used to extract the self-opening device from the trocar1100. Once the device is pushed from the trocar1100, the device will spontaneously open to form a polygon, as shown inFIGS.9A-10A. The trocar1100may be round in cross-section, or the trocar1100may be rectangular in cross-section to help the self-opening device to remain in a flat delivery configuration while it is delivered. (See right side ofFIG.11.) In other embodiments, non-magnetic inserts1150, or extruded shaped tubing, may be used to facilitate delivery of a self-opening device. Other configurations of self-opening devices, i.e., squares, hexagons, decagons, dodecagons, tetradecagons, hexadecagons, octodecagons, and icosagons, can also be delivered in a similar manner. In some instances, the pusher may have a lumen for a guide element as discussed below. In some instances, a laparoscopic manipulator (not shown) will be used to facilitate placement of the deployed device.

Because of the construction, the magnetic devices of the invention are relatively smooth and flat and present essentially uninterrupted annular faces. Because of this design, the devices do not cut or perforate tissue(s), but rather achieve anastomosis by providing steady necrotizing pressure across the contact surface between mating deployed devices. These features also reduce the risks associated with surgical access and ensure that the anastomosis is formed with the correct geometric attributes. Overall, the design ensures the patency of the anastomosis.

Like the self-opening devices ofFIGS.9A-10B, the self-closing devices of the invention can incorporate a variety of magnetic polar configurations, as shown inFIGS.12-15. As shown inFIG.12, a self-closing magnetic compression device100can be formed by delivering a polygon-closing assembly120to a set of magnetic segments140. The polygon-closing assembly120may be made from a resilient material that will retain its shape after deformation, such as a polymer or metal alloy. In some embodiments, the metal alloy will comprise nickel, such as nitinol. The magnetic segments140may be comprised of any strongly-magnetic material, such as rare earth magnetics, comprising materials such as neodymium, samarium, erbium, yttrium, ytterbium, and cobalt. In some embodiments, the magnetic segments may be coated, e.g., with gold or Teflon, to improve durability or biocompatibility. Once assembled, the resulting self-assembling magnetic anastomosis device can be intentionally deformed into a semi-linear shape, but will form a polygon when released, as shown inFIG.12.

During deployment, the polygon-closing assembly120acts as a hinge between magnetic segments140while coupling the structural rigidity of individual segments140similar to a cantilevered beam. In other words, the tensile modulus of the polygon-closing assembly120and the polygon-closing assembly's resistance to out-of-plane bending allow the forces on the distal end of the structure to be distributed across the magnetic segments140. The design allows a pushing force on the proximal end of the device in a delivery configuration to reliably move the distal end of the device, e.g., out of a deployment lumen such as the working channel of an endoscope. Because the polygon-closing assembly120is thin, and in close contact with the magnetic segments that are long relative to the length of their miter joints, the polygon-closing assembly120can bend to accommodate miter closure with relatively small strain. However, the breadth of the polygon-closing assembly120produces a high moment of inertia (stiffness) against out-of-polygonal-plane bending, thereby giving good guidance of the growing ring and providing lateral resistance to deflection during closure. Finally, the polygon-closing assembly120also provides a tensile coupling between the magnetic segments, assuring that the segments do not go past the closure point and collapse inward or over top of one-another.

As show inFIG.12, two self-assembling magnetic compression devices100can be associated as a matched set180. As described above, tissues that are trapped between the matched set180will be compressed, and eventually grow together, leaving an opening160in the tissue. As shown inFIG.12, each magnetic segment of the matched set180, has at least at least two poles183and185, with the poles oriented normal to the face of the polygon. When assembled, the poles of the segments in adjoining devices are arranged N/S/N/S or S/N/S/N. The aligned and matching poles in the matched set180form a very strong coupling between the two elements. Additionally, the attractive forces between opposing poles of nearby magnetic segments facilitates assembly of matched set180. Typically, the two elements of the matched set180need only to be placed in proximity to each other and the magnetic segments will self-align in the preferred configuration. In some instances, it is necessary to pre-align the complimentary devices, however, in other instances the devices self-align by undergoing fast in-plane rotation with respect to one another.

Additionally, like the self-opening devices ofFIGS.9A-10B, the self-closing devices ofFIGS.12-15can have a variety of magnetic polar arrangements, giving a user the ability to tune the amount of attractive force between devices at a distance. Typically, the arrangement of the magnetic segments is preset prior to attachment of the polygon-closing assembly120, as shown inFIGS.12-15. Because the polygon-closing assembly is non-magnetic, the completed self-closing device will have segments with polarities dictated by the polarities of the underlying magnetic segments140, as shown inFIGS.13-15. Again, the octagonal structures ofFIGS.12-15are illustrative, and should not be seen as limiting. In other words, self-closing structures that create squares, hexagons, decagons, dodecagons, tetradecagons, hexadecagons, octodecagons, or icosagons can be formed in a similar manner. Additionally, self-closing magnets may be constructed from an odd number of magnetic segments, including magnetic bipoles, as shown in the drawings, or magnetic quadrupoles, hexapoles, or octapoles, as may be required. It is not necessary that each magnetic segment is the same size or length.

Accordingly, the self-closing devices, constructed from linked magnetic multipole segments140, will form a polygon when extruded from the end of a delivery lumen, e.g., through a trocar or a working channel of an endoscope200, as shown inFIG.16. As each successive magnetic segment140emerges from the end of the working channel200into the surgical field, the polygon-closing assembly120constrains the segment against out-of-polygonal plane deflection and the segments' mutual attractions close each miter joint260in the correct inward direction, sequentially correct and, as the last segment is extruded, to close the polygonal magnetic ring. Furthermore, when the devices are constructed with symmetric miter joints and have their magnetic poles aligned with the annular axis of the polygon, the total magnetic force normal to the mating surfaces is maximized. The magnetic forces increase the mechanical stability of a set of coupled magnets while speeding anastomosis formation due to the intense compressive force on the trapped tissues.

In many instances, it is beneficial to be able to manipulate the location of a device after it has been delivered to a tissue. While the device can be manipulated with conventional tools such as forceps, it is often simpler to manipulate the location of the deployed device with a guide element220, such as a suture or wire. As shown inFIGS.17,18A-18D,19A-19D,20A-20D,21A-21D, and22, a variety of attachment points can be used to provide control over the location and deployment of a self-opening or a self-closing magnetic anastomosis device. The guide element220may extend proximally away from the surgical field and emerge, e.g., from a port or from the proximal end of the working channel of an endoscope.

For example, as shown inFIGS.18A-18D and22, the guide element220may be coupled to a single distal segment such that, upon deployment, the single distal segment results in an attachment point that provides translational freedom of movement. It is also notable that in the self-closing configuration shown inFIG.22, the guide element220allows a closing force to be applied to the distal-most segment. That is, in the event that one or more segments should become entangled with tissue, or otherwise prevented from closing, a proximal pulling force with the guide element220can help the device to complete self-assembly. Furthermore, once the device has achieved its deployed configuration, the device can be positioned with the guide element220to be mated with another device (not shown inFIGS.18A-18D and22) as described above. While it is not shown inFIG.22, it is envisioned that additional structures, such as a pusher1130, shown inFIGS.18A-18D and19A-19Dmay be used to deploy the device at the desired location. The pusher will typically be formed from a rigid non-interactive material, such as Teflon″″ or other polymer approved for surgical applications.

The guide element220can be fabricated from a variety of materials to achieve the desired mechanical properties and bio-compatibility. The guide element220may be constructed from metal, e.g., wire, e.g., stainless steel wire, or nickel alloy wire. The guide element may be constructed from natural fibers, such as cotton or an animal product. The guide element may be constructed from polymers, such as biodegradable polymers, such as polymers including repeating lactic acid, lactone, or glycolic acid units, such as polylactic acid (PLA). The guide element may also be constructed from high-tensile strength polymers, such as Tyvek™ (high-density polyethylene fibers) or Kevlar™ (para-aramid fibers). In an embodiment, guide element220is constructed from biodegradable suture, such as VICRYL™ (polyglactin910) suture available from Ethicon Corp., Somerville, NJ.

The guide element220can be coupled to the self-closing or self-opening device with a number of different configurations and attachment mechanisms. Additionally, the guide elements can be used in the same configurations regardless of the magnetic polar configuration of the devices. The guide element may be simply tied to the device, or the guide element220can be attached to the device with an adhesive, e.g., acrylate glue, or with a fastener, such as a clip, screw, or rivet.

In other embodiments, such as shown inFIGS.19A-19D and23, the guide element220may be attached to, or configured to interact with, more than one part of the device. For example,FIGS.19A-19Dshow a self-opening device, wherein a guide element220is coupled to the distal-most segment of a self-opening device, and configured to interact with radial members510that facilitate assembly and placement of the device. Alternatively, as shown inFIGS.20A-20D, two guide elements220may be coupled to the hinges to facilitate conversion from a delivery configuration to a deployed configuration. It should be noted that the guide elements220shown inFIGS.20A-20Dwould be on top of each other and taught when pulled, but have been shown apart for ease of viewing. Additionally inFIGS.20A-20D, the pusher1130can be used to manipulate the device once it has achieved a deployed configuration. Also, as shown inFIG.23, a guide element220may be coupled to the distal-most segment of a self-closing device, and configured to interact with radial members510that facilitate assembly and placement of the device. Furthermore, as shown inFIG.23, proximal force on the guide element220helps the device to close. As shown inFIGS.19A-19D and23, the radial members510also establish a center530of the device, which is coupled to the guide element220when the device has achieved a deployment configuration and the guide element220is pulled taut. The center530of the device can then be delivered to a desired location, e.g., opposite a mating device on the other side of a tissue.

FIGS.21A-21Dshow a different delivery technique, in which a guidewire1250is delivered to the area where an anastomosis is to be formed, after which a self-opening device can be delivered to the location using a pusher1130(motion shown with hashed arrow) while a sheath1220(motion shown with black arrow) is used to keep the self-opening device in a delivery configuration. Once the device has been delivered to the area, the sheath1220can be removed proximally, thereby allowing the self-opening device to transform to a deployment configuration. Once the sheath1220has been retracted suitably, the pusher1130can be used to place the device or help it to mate with a joining device. The delivery and deployment may be visualized, e.g., with fluoroscopy or ultrasound, and the device and the pusher1130may include markers, such as radiopaque markers, to facilitate visualization. Additionally, while not shown inFIGS.21A-21D, the device may include one or more guide elements220to improve deployment or to facilitate placement.

Like the guide elements220, the radial members510can be fabricated from a variety of materials to achieve the desired mechanical properties and bio-compatibility. The radial members510may be constructed from metal, e.g., wire, e.g., stainless steel wire, or nickel alloy wire. The guide element may be constructed from natural fibers, such as cotton or an animal product. The guide element may be constructed from polymers, such as biodegradable polymers, such as polymers including repeating lactic acid, lactone, or glycolic acid units, such as polylactic acid (PLA). The guide element may also be constructed from high-tensile strength polymers, such as Tyvek™ (high-density polyethylene fibers) or Kevlar™ (para-aramid fibers).

In an embodiment, the radial members510are constructed from biodegradable suture, such as VICRYL™ (polyglactin910) suture available from Ethicon Corp., Somerville, NJ

Additionally, the radial members510can be used in the same configurations regardless of the magnetic polar configuration of the devices.

EXAMPLES

Example 1: Calculation of Azimuthal Potentials

Azimuthal patterns were calculated for each of the self-opening configurations shown inFIGS.24-29.

The calculations begin with the assumption of perfect repulsive symmetry across the centerline of the self-opening rings, the line between the two internal hinges at either end of the delivery configuration and its two parallel rows of four magnet segments. With this assumed symmetry we need only enumerate the possible combinations of N's and S's along one of the four-segment ‘sides.’ There are only 16 such arrangements, 24, which can be easily spelled out:

1)NNNN2)NNNS3)NNSN4)NSNN5)SNNN6)NNSS7)NSSN8)SSNN9)SNNS10)SNSN11)NSNS12)NSSS13)SNSS14)SSNS15)SSSN16)SSSS

Because of centerline mirror symmetry, it can't matter from which end we start with the calculation. A pattern left-to-right must be the same entity as the same pattern from right-to-left, as well as being the same as the ‘reverse pattern (N/S swap equivalent to a ring flip)’ in either direction. So 1=16, 2=15=5=12, 3=14=4=13, 6=8.7=9, 10=11 and there are only 6 distinct patterns: 1, 2, 3, 6, 7, 10Configuration 1=16)=FIGS.9A,9B, and24.Configuration 2=5)=12)=15)=FIG.25.Configuration 3=4)=13)=14)=FIG.26.Configuration 6=8)=FIGS.9C and27.Configuration 7=9)=FIGS.9D and28.Configuration 10=11)=FIGS.10A and29.

The azimuthal properties of each pattern were calculated by drawing each octagonal magnet pattern onto duplicate mylar sheets. The potential energy of each segment's interaction with its mating neighbor is either −1, +1 or 0, attractive-repulsive-neutral. [As an approximation, each of the two inserted quadrupolar segments are deemed to have no interaction with any dipole segment; however a full interaction when one quadrupolar segment aligns with other quadrupole.] After the initial calculation, one of the mylar sheets is rotated 45 degrees and the new potential energy tabulated. Repeating this rotation and calculation step eight times results in a list of 8 numbers that describe the rings' interaction through one complete in-plane revolution relative to the other. Additional details of the calculations are presented below.

The numbers from the calculation are tabulated in an octagonal array (i.e., 12,1:30,3,4:30,6.7:30,9,10:30 on a clockface) where an adjacent number represents the potential energy of the rings after 45 degree rotation of one of the rings. The potential energy of the ring-pair is actually a smooth curve connecting these most easily calculated locations. Using this presentation, we can tabulate the azimuthal behavior of the six distinct patterns shown inFIGS.24-29(2Q versions thereof) as well as the potential energy of a closed ring (on the right), the sum of the miter interactions (compared with −8 of the earlier, completely self-assembling rings).

(1) −8 −8 −8 −8 −8 −8 −8 −88 repel (R)+8(2) −8 −2 0 −2 0 −2 0 −24 attract (A)/4 repel (R)0(3) −8 +2 0 −2 0 −2 0 +26A2R−4(6) −8 0 0 0 +8 0 0 04A4R0(7) −8 0 +4 0 −8 0 +4 06A2R−4(10) −8 +4 0 −4 +8 −4 0 +48R+8
Upon making the calculations, the following trends are noted:Configuration 1 (FIG.24) is unique in the absence of variation of attractive force with rotation. While there is no azimuthal variation, the lack of rotational force could potentially lead to mismatched devices and deviation in size and shape of the anastomosis. However, with proper placement, it is unlikely that the lack of rotational wells will be problematic. It is noteworthy that all of the mitered joints are repulsive in Configuration 1 (or almost all, if quadrupole segments are used at the end). For this reason, it may be beneficial to deploy self-opening devices of configuration 1 using guide elements, e.g., as discussed above.Configuration 2 (FIG.25) Numerous attractive wells, only one full depth.Configuration 3 (FIG.26) Numerous attractive wells, only one full depth, surrounded by 25% repulsive barriers.Configuration 6 (FIG.27) Good potential. While Configuration 6 has rotational potential wells, the wells are well-defined and aid alignment of the devices. Additionally, the force at a distance is almost as strong as Configuration 1. See, e.g.,FIG.7.Configuration 7 (FIG.28) Good potential. Slightly less force at a distance, rotational wells facilitate alignment, but provide more maneuverability because there are two equal wells with 180° of rotation of one device.Configuration 10 (FIG.29) Numerous potential wells, only one full depth, flanked by 50% repulsive barriers; the multiple rotational wells may make alignment more difficult.

Calculation of the repulsive and attractive forces for each self-opening configuration, with and without quadrupole end segments, is calculated as detailed, below. Each configuration, i.e., as shown inFIGS.24-29, has multiple diagrams, noted i, ii, iii, . . . viii. (Cross-hatched is N, solid is S.) Diagrams i, ii, and iii depict the configuration without quadrupolar segments, i.e., “nonQ” versions, whereas iv, v, and viii represent the configuration with the addition of one quadrupolar magnetic segment at each end, i.e., the “2Q” versions.

Because there is repulsion across each inner hinge, there is some advantage of adding an additional reversal, a quadrupole segment, that allows for attraction across what is otherwise repulsive miter. (No short range loss of force; some loss on long range interaction.) This 2Q version, with one for each inner hinge, is depicted in diagrams iv, v, and viii. (There are actually two ways to introduce the Q's, mirror images across the centerline. They are non-superimposable mirror images with equivalent behavior.)

Separately, each configuration includes a diagram vi that is a depiction of the ring's rotational interaction (nonQ numbers outside, 2Q numbers inside). With both rings perfectly aligned there is a maximal 8 units of attraction between all mated segments, depicted as −8 implying a potential energy well. As one magnet is held fixed and the other is rotated to one of the other 7 aligned positions the new potential energy of the ring couple is displayed there accordingly. +8 represents a condition of complete repulsion between all 8 pairs and 0 a balance between 4 attractive and 4 repulsive segment pairs. −2 slight attraction. +2 slight repulsion. The lower the number the greater the rings' total attractive force in that orientation. Additionally, there is an applied torque proportional to the change in energy as function of azimuthal angle. Configuration 1, diagram vi shows that coupling of these ‘unipolar rings’ would not require rotation, nor could coupling induce rotation. Configuration 2, diagram vi shows that the 2Q (inner) version would have distracting weak minima at 4:30 and 7:30 from the real direction. Configuration 3, diagram vi shows strong ‘half-deep’ wells in the nonQ configuration may make alignment tricky during a procedure. Configuration 6, diagram vi suggests beneficial properties both in terms of alignment and closing, and has favorable long-distance properties, as discussed above. Configuration 7, diagram vi suggests that configuration 7 doesn't have to rotate as far as configuration 6, but has slightly inferior long distance interactions. Configuration 10, diagram vi, suggests a variety of local minima, which may result in disfavored performance. Configuration 10 additionally experiences less attractive force at a distance, which may make coupling more difficult through. e.g., thick tissues.

INCORPORATION BY REFERENCE

References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.

EQUIVALENTS

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.