Abstract:
Stitching apparatus and methods are provided for placing a stitch through a layer of material such as tissue. Preferred methods include piercing a needle element through tissue, engaging a thread with the needle, and pulling the thread through the tissue. The needle suitably releasably engages the thread, e.g. magnetic engagement of the needle and thread.

Description:
[0001]    The present application claims the benefit of U.S. provisional application number 61/922,595, filed Dec. 31, 2013, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    (a) Technical Field 
         [0003]    The present invention relates to a stitching apparatus for placing a stitch through a layer of material such as tissue. In particular aspects, the present invention relates to stitching apparatus and methods that pierce through a layer of material such as tissue, engages a thread, and pulls the thread through the layer of material. 
         [0004]    (b) Background Art 
         [0005]    Stitches are often used in a myriad of industries to bind two pieces of material together. For example, the medical industry often uses stitches to suture layers of tissue together during surgical procedures, thereby allowing the layers of tissue to fuse while healing. A suture needle is typically used to force a suture thread through the separate layers of tissue to allow the suture thread to bind the tissue layers. 
         [0006]      FIGS. 1-3B  illustrate the configuration of a traditional suture needle used during medical procedures. As shown in  FIG. 1 , a typical suture needle  100  includes a needle body  102  having a needle point  104  on one end and a suture connection point  106  on the opposite end. Suture connection point  106  connects suture needle  100  to a suture thread and may be of an eyeless configuration. For example, suture connection point  106  may be swaged to an end of the suture thread. Generally, suture needles are classified based on their length, diameter and percentage of curvature relative to a center location. As shown, for example, suture needle  100  has a needle length  112 , a diameter  110 , and is a “half circle” type of suture needle since its length  112  extends along exactly half the perimeter of a circle having center  114  and radius  116 . Other common types of suture needles (not shown) include “quarter circle,” “three eights circle,” and “five eights circle” suture needles. Typically, longer suture needles (e.g., three eights circle needles) are used for large or superficial wounds while shorter suture needles (e.g., half circle or five eights circle needles) are used for cases in which access or room for manipulation is limited, such as in small and deep spaces. 
         [0007]      FIGS. 2A-2B  depict the use of a suture needle  200  coupled with a suture thread  206  to first layer of material  208 . As shown in  FIG. 2A , needle point  202  of suture needle  200  is inserted through material  208  at puncture point  212  by applying an insertion force to suture needle  200 , thereby penetrating material  208 . Additional insertion force may then be used to drive the remainder of suture needle  200  through material  208 , as shown in  FIG. 2B . Suture thread  206 , which is coupled to suture needle at connection point  204 , is pulled along when the insertion force is applied to suture needle  200 , thereby pulling suture thread  206  through puncture point  212  and to the opposite side of material  208 . This process may then be repeated with a second layer of material  210  to bind materials  208 ,  210  together using suture thread  206 . 
         [0008]      FIGS. 3A-3B  illustrate the use of surgical tools that are commonly used in conjunction with a suture needle, when a medical procedure is performed. As shown in  FIG. 3A , a suture needle  300  attached to a suture thread  302  may be gripped using a needle holder  304 . A user operating needle holder  304  grasps one end of needle holder  304  to apply a compressive force to suture needle  300  that allows suture needle  300  to be manipulated using needle holder  304 . In  FIG. 3B , a vessel anastomosis procedure is illustrated in which suture thread  302  has been threaded through a first vessel wall  308  and is in the process of being threaded through a second vessel wall  310 . By manipulating needle holder  304 , the user is able to apply an insertion force to suture needle  300  to pierce vessel wall  310  and insert suture needle  300  through vessel wall  310 . Typically, the user also uses a pair of tweezers  306  to grip the portion of suture needle  300  that has protrudes from vessel wall  310  after insertion of suture needle  300  through vessel wall  310 . The user may then continue applying an insertion force to suture needle  300  by continuing to push suture needle  300  through vessel wall  310  and/or by pulling suture needle  300  through vessel wall  310  using tweezers  306 . As a result of this process, suture thread  302  will eventually extend through both vessel walls  308 ,  310 . The process is then repeated any number of times in an alternating manner between vessel walls  308 ,  310  to form stitches using suture thread  302 , thereby binding vessel walls  308 ,  310  together. 
         [0009]    In the stitching process described above, a traditional suture needle is required to have at least minimum length due to the use of a needle holder and tweezers. In other words, a traditional suture needle must be long enough to allow it to be gripped by both the needle holder and tweezers simultaneously, while still accounting for the thickness of the tissue. In addition, 3-4 times the amount of needle length space is needed in a traditional suture needle to prevent the needle from accidentally puncturing neighboring tissue. However, the size constraints on traditional suture needles also prevent them from accessing certain angles or surgical fields. For example, a traditional suture needle may be too large to access certain deep, small, narrow, or serpentine working spaces. 
       SUMMARY 
       [0010]    We now provide systems and methods for passing a thread element through a material, particularly a suture through tissue of a subject that includes (a) piercing a needle element through tissue; (b) engaging a suture with the needle; and (c) pulling the suture through the tissue. Preferably, the needle element releasably engages the suture element e.g. the reliable engagement may be magnetic, mechanical or adhesive or other chemical releasable engagement. Magnetic releasable engagement of the needle and suture elements is particularly suitable for many systems. 
         [0011]    We have found that the systems and methods of the invention can utilize a needle of particularly short dimensions (length) in comparison to traditional stitching tools. In the present methods, the needle element first pierces through tissue and then couples with and withdraws the suture element through the tissue puncture point already established by the first piercing of the needle. This can enable use of a needle element of comparatively small dimensions and suturing can be accomplished within confined spaces relative to prior approaches where a suture material and needle element are initially coupled together and that suture/needle assembly is advanced together for the first time through tissue. Additionally, by first establishing a puncture point in accordance with the present methods, the suture material can be advanced through the puncture point in the tissue with little resistance. 
         [0012]    In preferred system, a needle element may comprise a thread extractor which engages an end of the thread element such as a suture. An end portion of the needle element may comprise an enclosure that houses a thread extractor element and at least partially encases an end of the suture when the suture is engaged to the thread extractor element. In particular preferred systems, the thread extractor may comprise a magnet that engages a thread end portion by magnetically coupling the thread end portion to the thread extractor. 
         [0013]    In additional preferred systems, the stitching apparatus includes a handle portion configured to be gripped by a user and an insertion portion coupled to the handle portion that is configured to be inserted through a layer of material. The insertion portion may include a needle tip configured to pierce through the layer of material when an insertion force is applied to the needle tip. The insertion portion also may include an elongated base coupling the needle tip to the handle portion and configured to transfer the insertion force from the handle portion to the needle tip. The insertion portion may further include a thread extractor configured to engage a thread tip when the insertion portion has been inserted through the layer of material and further configured to transfer an extraction force from the handle portion to the thread tip to pull the thread tip through the layer of material. 
         [0014]    In one embodiment, the needle tip and elongated base may define a hollow enclosure that houses the thread extractor and enshrouds the thread tip when the thread tip is engaged to the thread extractor. The elongated base and needle tip may also extend along an axis radial to the handle portion. Alternatively, the elongated base may extend from the handle portion along a curved path. 
         [0015]    According to various embodiments, the thread extractor may include an adhesive material that adheres the thread tip to the thread extractor, a magnet (e.g., a permanent magnet, an electromagnet, etc.) that engages the thread tip by magnetically coupling the thread tip to the thread extractor, one or more apertures that engage the thread tip, or one or more protrusions that engage the thread tip. In embodiments that include an electromagnet, the handle of the stitching apparatus may also include electronics configured to provide electrical power to the electromagnet. The electronics may further include a battery housed by the handle portion that supplies power to the electromagnet or an electronic switch configured to control the supply of power to the electromagnet when activated by the user. 
         [0016]    In another preferred embodiment, stitching methods are provided that include transferring an insertion force from a handle to a needle tip and piercing through a layer of material using the needle tip to insert an insertion portion through the layer of material. The method also may include engaging a thread extractor of the insertion portion to a tip of a thread while the insertion portion is inserted through the layer of material. The method may further include transferring an extraction force from the handle to the tip of the thread. The method additionally may include pulling the thread through the layer of material by extracting the insertion portion from the layer of material. 
         [0017]    In yet a further embodiment, stitching apparatus are provided that that includes means for transferring an insertion force from a handle to a needle tip. The stitching apparatus also may include means for piercing through a layer of material using the needle tip to insert an insertion portion through the layer of material. The stitching apparatus may further include means for engaging a thread extractor of the insertion portion to a tip of a thread while the insertion portion is inserted through the layer of material. The stitching apparatus additionally may include means for transferring an extraction force from the handle to the tip of the thread. The stitching apparatus also may include means for pulling the thread through the layer of material by extracting the insertion portion from the layer of material. 
         [0018]    A variety of configurations of the disclosed stitching apparatus and methods will be suitable and preferred for many applications. 
         [0019]    For instance, a magnet or other gripping force element may be molded or otherwise produced as a single unit with a needle element. 
         [0020]    Alternatively, a magnet or other gripping force element may be separated (spaced and/or no physical attachment) to a needle element. In one preferred embodiment, the needle element suitably is within the magnetic field of the unattached magnet or within the attractive field of other gripping force element (such as a vacuum). In such systems, the needle element itself suitably would not need to be magnetized. 
         [0021]    In other preferred embodiments, the needle element in whole or part may be magnetized. In such embodiments, with use of a hollow needle, the hollow needle lumen may serve as a path for entry of the thread element. 
         [0022]    Needle elements of a variety of designs and configurations suitably can be employed. For instance, in addition to a hollow needle element, a needle element without a lumen suitably may be utilized. Both sharp and blunt-ended needles may be suitably employed. 
         [0023]    Also, as mentioned, a thread element may be engaged to a needle element through one or more of a variety of attractive forces. In many embodiments, use of a magnetic to engage the tread and needle elements will be preferred. Use of a vacuum also could be employed to engage the thread and needle elements. Mechanical and adhesive engagement of thread and needle elements also suitably can be utilized. 
         [0024]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given herein by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0026]      FIG. 1  is an illustration of a suture needle. 
           [0027]      FIG. 2A  is an image depicting a suture needle being inserted through a layer of material. 
           [0028]      FIG. 2B  is an image depicting the suture needle of  FIG. 2A  having been pulled entirely through the layer of material. 
           [0029]      FIG. 3A  is an illustration of a needle holder grasping a suture needle. 
           [0030]      FIG. 3B  is an illustration of a vessel anastomosis procedure being performed using the needle holder and suture needle of  FIG. 3A  with a pair of tweezers. 
           [0031]      FIG. 4  is an image depicting a stitching apparatus, according to one exemplary embodiment. 
           [0032]      FIG. 5  is an image depicting the insertion portion of a stitching apparatus in greater detail. 
           [0033]      FIG. 6A  is an image depicting an insertion force being applied to a stitching apparatus to puncture a layer of material. 
           [0034]      FIG. 6B  is an image showing a thread tip in close proximity to the stitching apparatus of  FIG. 6A . 
           [0035]      FIG. 6C  is an image of the thread tip of  FIG. 6B  engaging a thread extractor of the stitching apparatus of  FIGS. 6A-6B . 
           [0036]      FIG. 6D  is an image depicting an extraction force being applied to the stitching apparatus of  FIGS. 6A-6C  to pull the thread tip through the layer of material. 
           [0037]      FIG. 7  is a schematic diagram of a stitching apparatus that uses an electromagnetic thread extractor. 
           [0038]      FIG. 8  is a schematic diagram of a stitching apparatus having a curved insertion portion. 
           [0039]      FIG. 9A  is a cross-sectional view of the insertion portion of a stitching apparatus having locking protrusions. 
           [0040]      FIG. 9B  is a cross sectional view of a thread tip having apertures that engage the locking protrusions of  FIG. 9A . 
       
    
    
       [0041]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0042]    In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
       DETAILED DESCRIPTION 
       [0043]    The present stitching apparatus and methods can provide numerous advantages. For instance, as discussed, the insertion portion of the stitching apparatus may be much shorter than that of traditional needles, such as suture needles. This can allow a user to be able to place stitches in traditionally inaccessible places. Additionally, the short insertion portion of the stitching apparatus can have less of a chance of accidentally puncturing neighboring tissue than traditional needles, when used in a surgical procedure. 
         [0044]    Referring now to  FIG. 4  of the drawings, a preferred stitching apparatus  400  is shown, according to an exemplary embodiment. Stitching apparatus  400  includes a handle portion  402  that can be gripped by either hand of a user to manipulate stitching apparatus  400 . Stitching apparatus  400  also includes an insertion portion  404  that can be at least partially inserted through a layer of material by manipulation of handle portion  402  by a user. 
         [0045]    Handle portion  402  of stitching apparatus  400  may be of any size or shape, according to various embodiments. In some cases, handle portion  402  may be ergonomically shaped to fit one or both hands of a user. The width of handle portion  402  may also be uniform or may vary along the length of handle portion  402 . For example, the width of handle portion  402  may be tapered closest to the junction between handle portion  402  and insertion portion  404 , thereby minimizing the size of stitching apparatus  400  in the work area. 
         [0046]    Insertion portion  404  of stitching apparatus  400  may be permanently affixed to handle portion  402  or may be detachable. In various embodiments, handle portion  402  and insertion portion  404  may be forged from a single piece of metal, insertion portion  404  may be welded or otherwise adhered to handle portion  402 , or insertion portion  404  may engage an internal latching mechanism of handle portion  402  that prevents detachment of insertion portion  404  once latched to handle portion  402 . In other embodiments, insertion portion  404  may releasably engage handle portion  402  via threading (e.g., insertion portion  404  may include threading and can be screwed into handle portion  402 ), a latching mechanism that can be actuated to release insertion portion  404  from handle portion  402  (e.g., via the push of a button, the movement of a switch, etc.), or any other mechanism that allows insertion portion  404  to be separated from handle portion  402 . 
         [0047]    Insertion portion  404  includes an elongated base  406  that extends radially from handle portion  402  at a substantially perpendicular angle, in one embodiment, or in other embodiments any other angle may be utilized including acute or obtuse angles. Elongated base  406  may generally be of a cylindrical shape with a circular or ovoid diameter. In other embodiments, elongated base  406  may extend from handle portion  402  along a curved path, as shown in greater detail in  FIG. 8 . Elongated base  406  may be solid or may include a hollow portion that partially or fully extends along the length of elongated base  406 . Any length can be selected for elongated base  406 . Preferably, a minimal length for elongated base  406  is selected such that elongated base  406  is able to extend through the width of a layer of material while still allowing the greatest degree of movement for the operator. 
         [0048]    At the end of insertion portion  404  opposite the junction between handle portion  402  and insertion portion  404  is a needle tip  408 . Needle tip  408  is formed by tapering or beveling elongated base  406  in a direction away from handle portion  402  and is driven by elongated base  406  to pierce through a layer of material. The edge of such a bevel may be entirely blunt, entirely sharp, or only partially sharp. Additionally, as discussed above, insertion portion  404  need not comprise a lumen. 
         [0049]    Referring now to  FIG. 5 , the insertion portion  404  of stitching apparatus  400  is shown in greater detail. As shown, elongated base  406  may be of a hollow, cylindrical shape having an unbeveled portion  414  and a beveled portion  412  that exposes interior  416  of the hollow base  406 . In some cases, the length and location of beveled portion  412  along elongated base  406  may be selected to increase the user&#39;s vision of interior  416  of insertion portion  404 . For example, beveled portion  412  may extend along a greater length of elongated base  406  than that of unbeveled portion  414 . In one embodiment, unbeveled portion  414  has a length that corresponds to the width of the tissue through which a thread is to extend as part of a stitch. The diameter of interior  416  can be selected to be slightly greater than the diameter of a thread tip affixed to the end of a thread such that the thread tip may be partially or fully inserted into interior  416  of elongated base  406 . 
         [0050]    In various embodiments, insertion portion  404  includes a thread extractor that engages a thread tip after insertion portion  404  has been driven through a layer of material. In configurations in which elongated base  406  is hollow, the thread extractor may be located within the hollow interior  406 . In configurations in which elongated base  406  has a curved shape, the thread extractor may be located at any along the peripheral of elongated base  406  such that the thread extractor may engage the thread tip via a scooping action. The thread extractor may be located within unbeveled portion  414  along interior  416  and/or may extend from elongated base  406  into handle portion  402 . 
         [0051]    Referring now generally to  FIGS. 6A-6D , the operation of stitching apparatus  400  is shown threading a piece of thread through a layer of material. As shown, one or more stitches can be applied between two layers of material  602 ,  604  using stitching apparatus  400 , to bind materials  602 ,  604  together. Materials  602 ,  604  may be, but are not limited to, living tissues, fabrics, polymers, combinations thereof, or the like. Thus, stitching apparatus can be adapted for use with any number of different materials having varying thicknesses and durabilities. 
         [0052]    In  FIG. 6A , stitching apparatus  400  is manipulated by a user via handle portion  402  to drive at least a portion of insertion portion  404  through material  602  at puncture point  606 . An insertion force (F) applied by the user via handle portion  402  is transferred through elongated base  406  to needle tip  408 . For example, the insertion force may be applied to needle tip  408  along an axis that extends through elongated base  406  and needle tip  408  radially from handle portion  402 . When the insertion force is applied to needle tip  408 , needle tip pierces material  602  at puncture point  606 . Additional application of the insertion force causes insertion portion  404  to be driven through the material  602 . 
         [0053]    In  FIG. 6B , a thread  612  is moved within proximity of insertion portion  406  of stitching apparatus  400 . Thread  612  may be any form of thread (e.g., wire, fiber, etc.) suitable for binding materials  602 ,  604  together. In surgical applications, thread  612  may be a suture thread designed for use with organic tissue and may be composed of an absorbable or non-absorbable material. For example, thread  612  may be composed of an absorbable material such as catgut, polyglycolic acid, polyactic acid, polydioxanone, caprolactone, or the like. Exemplary non-absorbable materials include polypropylene, polyester, nylon, metallic wires, and the like. In some cases, thread  612  may be coated with a compound that reduces friction during the stitching process, has antibacterial properties, and/or produces a biological reaction in the subject of the procedure (e.g., acts as an anti-inflammatory, etc.). 
         [0054]    At one end of thread  610  suitably is a thread tip  610  that has a diameter equal to or greater than that of thread  610 . As shown, thread tip  610  may be sized appropriately for insertion into interior  416  of elongated base  406 , if elongated base  406  has a hollow configuration. In such a case, the bevel of elongated base  406  used to form needle tip  408  may be used to visually align thread tip  610  with interior  416  thread tip  610  to be inserted into elongated base  406 . Thread tip  610  may be swaged or otherwise coupled to the end of thread  610  such that movement of thread tip  610  transfers a corresponding force to thread  610 . 
         [0055]    In  FIG. 6C , thread tip  610  has been partially inserted into interior  416  of elongated base  406 . The bevel of elongated base  406  acts to help retain thread tip  610  during insertion into stitching apparatus  400  and to provide the user with a visual indication of its progress. At full insertion into elongated base  406 , thread tip  610  engages a thread extractor (not shown) that is located within interior  416  and couples thread tip  610  to stitching apparatus  400 . 
         [0056]    The internal thread extractor of stitching apparatus  400  may be of various configurations that permanently or releasably couple thread tip  610  to stitching apparatus  400 . In one embodiment, the internal thread extractor may be a magnet and thread tip  610  may be composed of an oppositely polarized magnet or other material that exhibits magnetic properties when in the presence of a magnetic field. Thus, the thread extractor may exert a magnetic force that magnetically couples thread tip  610  to the thread extractor. The magnet of the thread extractor may be a permanent magnet or an electromagnet that is selectably powered to generate a magnetic field, in various embodiments. Thus, thread tip  610  may be released from the electromagnet at a later time either by removing the power to the electromagnet (e.g., to removing the magnetic force applied to thread tip  610 ) or by reversing the polarity of the magnetic field (e.g., by creating a magnetic force in the opposite direction, thereby forcing thread tip  610  out of extended base  406 ). 
         [0057]    In cases in which a magnetic force is used to couple thread tip  610  and stitching apparatus  400 , extended base  406  and/or thread  612  may be formed using non-magnetic material to prevent misalignment of thread tip  610  during use. For example, extended base  406  may be constructed using ceramics, carbon fiber, or another such material that does not react to the magnetic field of the thread extractor and retains its rigidity enough to pierce through material  602 . Similarly, thread  612  may be constructed using a non-magnetic material, such as nylon, to prevent thread  612  from accidentally being attracted to stitching apparatus  400 . 
         [0058]    In another embodiment, the thread extractor may be an adhesive material applied within interior  416  of elongated base  406 . For example, interior  416  may be coated with a glue that adheres thread tip  610  to interior  416 . In another example, both interior  416  and thread tip  610  may be coated with compounds that chemically react to form a bond (e.g., a polyurethane resin/polyester resin pair or the like). 
         [0059]    In yet further embodiments, the thread extractor may correspond to protrusions and/or apertures located within interior  416  of extended base  406 . For example, hook and loop fasteners may be affixed to the exterior of thread tip  610  and to interior  416  of extended base  406  to engage thread tip  610  to stitching apparatus  400 . In another example, one or more protrusions may be located within interior  416  that engage one or more slots located on thread tip  610  or vice-versa, as shown in more detail in  FIGS. 9A-9B . 
         [0060]    In  FIG. 6D , an extraction force (F e ) is shown being applied to thread tip  610  to pull thread tip  610  and thread  612  through puncture point  606 . The extraction force may be applied in substantially the opposite direction as the insertion force used to drive insertion portion  404  through material  602 . During extraction, thread extractor transfers the extraction force exerted by the user on handle portion  402  to thread tip  610 . Since the binding force exerted by thread extractor on thread tip  610  is greater than the extraction force, thread tip  610  is forced to move with insertion portion  404  back through puncture point  606 , thereby extending thread  606  through material  602 . After thread  612  has been threaded through puncture point  606 , thread tip  610  may be decoupled from the thread extractor (e.g., by manually breaking the bond, by deactivating a magnetic bond, etc.). The steps depicted in  FIGS. 6A-6D  can then be repeated any number of times in an alternating fashion between materials  602 ,  604  to form stitches between the two using thread  606 . 
         [0061]    Notably, compared to traditional methods, there would be little resistance for thread to go through the puncture point  660 , to another side of  602 , since the puncture point  606  was pierced previously by the needle element, and the thread is now inside the hollow space  610 ′. 
         [0062]    Referring now to  FIG. 7 , a schematic diagram of a stitching apparatus  700  is shown that uses an electromagnetic thread extractor. Similar to stitching apparatus  400 , stitching apparatus  700  includes a handle portion  702  and an insertion portion  704  that includes a beveled needle tip  706 . Insertion portion  704  defines a hollow space through which thread tip  710  has been inserted. Thread tip  710  is coupled to thread  708  such that movement of either thread tip  710  or thread  708  causes the other to move. 
         [0063]    In various embodiments, insertion portion  704  includes an electromagnet  712  that exerts a magnetic force on thread tip  710  when active. The polarity of electromagnet  712  may be selected such that, when current is supplied to electromagnet  712 , the resulting magnetic field draws thread tip  710  towards electromagnet  712  and couples thread tip  710  to electromagnet  712 . In one embodiment, electromagnet  712  is a solenoid having windings along the interior of insertion portion  704  and extending radially away from handle portion  702 . In another embodiment, electromagnet  712  is located partially or fully outside of the interior of insertion portion  704 . In such a case, electromagnet  712  may be configured such that the flux path of its resulting magnetic field passes through at least a portion of the interior of insertion portion  704 , thereby exerting a magnetic force on thread tip  710 . 
         [0064]    Stitching apparatus  700  may include power electronics  716  that provide current to the windings of electromagnet  712  from a power supply  718  via wires  714 , to induce a magnetic field. Power electronics  716  and/or power supply  718  may be housed within handle portion. For example, power supply  718  may include one or more batteries (e.g., storage cells, supercapacitors, etc.) that allow stitching apparatus  700  to be fully portable. In another example, power supply  718  may be external to stitching apparatus  700  (e.g., power supply  718  may be an external battery, a wall socket, etc. coupled to power electronics  716 ). 
         [0065]    Power electronics  716  operate to control the flow of current to electromagnet  712  in one or more directions. For example, power electronics  716  may have two or three modes of operation. In a dual mode configuration, power electronics  716  may induce an attractive magnetic field when active (e.g., forcing thread tip  710  toward stitching apparatus  400 ) and remove the magnetic field when deactivated. In a tri-mode configuration, power electronics  716  may induce an attractive magnetic field, induce a repulsive magnetic field by reversing the polarity to electromagnet  712  (e.g., forcing thread tip  710  away from stitching apparatus  400 ), or remove the current to electromagnet  712  completely to deactivate the magnetic field. In one embodiment, power electronics  716  includes a switch  720  located on the exterior or handle portion  702  that controls the mode of operation of power electronics  716 . 
         [0066]    Referring now to  FIG. 8 , a stitching apparatus  800  is shown, according to an exemplary embodiment. Stitching apparatus  800  includes a handle portion  802  that is grasped by a user to manipulate stitching apparatus  800 . Stitching apparatus  800  also includes a curved insertion portion  804  connected to handle portion  802 . At the end of insertion portion  804  opposite handle portion  802  is a needle tip  812  used to puncture through a layer of material in response to the user applying a force to handle portion  802 . Such an insertion force may be at least semicircular in direction, allowing the user to “hook” insertion portion  804  through the layer of material. 
         [0067]    As discussed above, a variety of other systems may be used to engage thread element and needle elements, including a vacuum system, for example where the needle element would exert a vacuum force to attract and engage the thread portion to the needle element. 
         [0068]    At the base of insertion portion  804  is a thread extractor  806  that engages a thread tip  808  connected to thread  810 . Thread extractor  806  may extend outward from handle portion  802  or may be located at least a fraction of the way into the interior of handle portion  802 . In one embodiment, thread extractor  806  includes a magnet that attracts thread tip  808 , thereby coupling thread tip  808  to stitching apparatus  800 . In some cases, insertion portion  804  and/or handle portion  802  may define a hollow space that shrouds thread tip  808  when coupled to thread extractor  806 . When thread tip  808  is coupled to thread extractor  806 , an extraction force may be transferred from handle portion  802  to thread tip  808  to pull thread  810  through the puncture point created by needle tip  812  in the layer of material. 
         [0069]    Referring now to  FIGS. 9A-9B , cross sectional views of an insertion portion  900  of a stitching apparatus and a thread tip  910  are shown, respectively. In  FIG. 9A , insertion portion  900  defines a hollow space  902  having a diameter slightly larger than that of thread tip  910 , allowing thread tip  910  to be inserted into insertion portion  900 . Protruding radially inward from the periphery of hollow space  902  is a plurality of locking protrusions  904 . One or more locking protrusions  904  may be used, in various embodiments. 
         [0070]    Thread tip  910  may include any number of apertures  912  that correspond to protrusions  904  of insertion portion  900 . Apertures  912  may extend radially inward from the perimeter of thread tip  910  relative to an axis  914  that passes through the center of thread tip  910 . Apertures  912  may be shaped such that two or more motions of insertion portion  900  and/or thread tip  910  causes protrusions  904  to engage apertures  912 , thereby locking thread tip  910  into insertion portion  900 . In some embodiments, apertures  912  of thread tip  910  may be of an “L” or “J” shape such that a first motion is used to insert protrusions  904  into apertures  912  and a second or subsequent motion is used to lock protrusions  904  into place. For example, thread tip  910  may be inserted into hollow space  902  of insertion portion  900  along axis  914 , to first engage protrusions  904  with apertures  912 . Thread tip  912  and/or insertion portion  900  may then be rotated about axis  914  to lock protrusions  904  into place on thread tip  910 . Once locked into place, protrusions  904  transfer any subsequent force exerted to thread tip  910  along axis  914 , such as an extraction force used to pull thread tip  910  through a layer of material. 
         [0071]    In an alternate embodiment, apertures  912  may be located within hollow space  902  of insertion portion  900  and protrusions  904  may extend radially outward from thread tip  910 . In yet another embodiment, apertures  912  and corresponding protrusions  904  may be distributed among thread tip  910  and insertion portion  900  such that each has at least one aperture and at least one protrusion. 
         [0072]    The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.