Abstract:
A method of suture welding is disclosed which includes: receiving suture segments between first and second jaw members, the first and second jaw members being in an open state. closing the first and second jaw members to captively hold and position the suture segments between the first and second jaw members; selectively applying an elongated joiner element to the suture segments where the joiner element has a selectively operative heating element facing the suture segments; and applying energy to the heating element to weld the suture segments-to-be-welded, whereby the heating element has a temperature above a predetermined threshold adapted to at least partially melt the suture segments.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. application Ser. No. 11/959,908, filed Dec. 19, 2007, which claims priority from U.S. Provisional Application Ser. No. 60/876,458 filed Dec. 20, 2006 and U.S. Provisional Application Ser. No. 60/876,196 filed Dec. 20, 2006, each of which are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND 
       [0002]    The invention relates generally to improvements in suturing apparatus and suturing techniques, and more particularly to devices for making thermal suture welds during surgical procedures. 
         [0003]    In surgical procedures, it is important to be able to form and secure sutures in place at the situs of surgery. The suture generally is directed through the portions of the tissue to be joined and formed into one or more single loops or stitches which then are knotted or otherwise secured to maintain the wound edges in the appropriate relationship to each other to facilitate proper healing. During surgical procedures involving delicate organs or tissues, or when the surgical site is relatively small or restricted, such as during endoscopic surgery, the formation of knots is cumbersome and often impractical. In such instances, a fused suture loop may be used to provide the appropriate tension on the tissue to be repaired and the appropriate strength to maintain the tissue repair as desired to allow proper healing to occur. 
         [0004]    One method of forming suture loops often used during such surgeries is suture welding, whereby adjacent segments of the sutures are fused together upon the application of sufficient heat to the suture segments to cause partial melting and fusion of the suture segments, followed by cooling and fusion, to form one or more closed suture loops. 
         [0005]    Such welding can occur, for example, due to direct application of ultrasonic energy to one or more of the suture segments-to-be-joined, so that vibratory motion between the suture segments causes frictional heating and consequent melting and fusion of the suture segments. Existing devices for forming welded sutures often produce undesirable heating of the surrounding tissue caused by the direct application of heat. As a result, other methods of suture welding, including ultrasonic energy-driven have increasingly been used for such endoscopic suture welding. However, ultrasonic suture welding is difficult with monofilament suture, and requires expensive metal jaws to isolate the ultrasonic energy. It is desirable to utilize thermal forms of suture welding to provide a cost-effective method of welding multifilament suture. 
         [0006]    In the surgical procedures that are complicated, e.g., in procedures involving suturing multiple arteries, muscles, veins, and the like, in an endoscopic environment, it remains a desire to produce the welded sutures in a short time frame currently unavailable using existing apparatus and methods. For these reasons, there remains a need in the surgical field for a suture welding apparatus and methods directed to thermal suture welding to produce suture welds of improved strength and reliability for use with multifilament suture materials, in both open and restricted (e.g. endoscopic) surgical fields. 
       SUMMARY 
       [0007]    The present disclosure is directed to a method and devices for providing strong, reliable thermal welded sutures, particularly suited for use in endoscopic surgery, but is suitable also for use in an open surgical field. The invention is applicable to both monofilament suture materials and multifilament suture materials. 
         [0008]    In one aspect, a suture welding device is disclosed which includes: an elongated tube extending along a central axis between a proximal end and a distal end, and a suture positioning assembly affixed to the distal end of the tube. The suture positioning assembly includes a first jaw member extending along a first jaw axis from a proximal end and a distal end, and a second jaw member extending along a second jaw axis from a proximal end and a distal end. At least one of the first and second jaw member includes an anvil portion at a distal end extending transverse to its respective jaw axis. The suture positioning assembly also includes a grasp assembly adapted to position the first jaw member opposite the second jaw member, the grasp assembly being selectively operative to position the first and second jaw members between two states: a first state where the first jaw member and the second jaw member are relatively divergent at the distal ends of the jaw members; and a second state where the first jaw member and the second jaw member are relatively non-divergent at the distal ends of the jaw members. The jaw members are adapted to captively hold and position suture segments-to-be-welded between the first and second jaw members when the grasp assembly is in the second state. 
         [0009]    The suture welding device also includes an elongated joiner element extending along the central axis between a proximal end and a distal end, the joiner element having a selectively operative heating element disposed at the distal end of the joiner element; a compression and weld assembly operative to translate the joiner element along the central axis whereby in a first preparatory state, the distal end of the joiner element is relatively far from the anvil portion of the at least one jaw, and in a weld state, is relatively near and biased toward the anvil portion of the at least one jaw; and a weld controller selectively operative when the grasp assembly is in the second state and the compression and weld assembly is in the weld state, to apply energy to the heating element, whereby the heating element has a temperature above a predetermined threshold adapted to at least partially melt the suture segments captively held between the jaws. 
         [0010]    In some embodiments, the first jaw member includes an anvil portion at the distal end extending transverse to the first jaw axis, and the second jaw member includes an anvil portion at the distal end extending transverse to the second jaw axis. 
         [0011]    In some embodiments, the jaw members are adapted to position two suture segments of diameter D held therein in the second state with the suture segments being side-by-side transverse to the central axis, being side-by-side along the central axis, or being side-by-side along an axis oblique with respect to the central axis. 
         [0012]    In some embodiments, the elongated tube is flexible. In some embodiments, the elongated tube is rigid. 
         [0013]    In some embodiments, the suture segments are manufactured from materials that enable welding of such suture segments 
         [0014]    In some embodiments, the joiner element remains within the suture positioning assembly during welding. In some embodiments, the joiner element extends beyond the suture positioning assembly during welding. 
         [0015]    Some embodiments include an elongated sleeve member extending along the central axis. The sleeve member may include: a first hook member extending along the central axis and adjacent one side of the suture positioning assembly; having an inner surface thereof positioned transverse to the suture segments when the suture segments are captively held between the first and second jaw members; and a second hook member extending along the central axis and adjacent to a side of the suture position assembly opposite the first hook member, and having an inner surface thereof positioned transverse to the suture segments when the suture segments are captively held between the first and second jaw members. The suture positioning assembly is slidably engaged within the sleeve member to selectively cut the suture segments. In some embodiments, the first and second hook members are positioned downward relative to the central axis. 
         [0016]    Some embodiments include an elongated sleeve member extending along the central axis from a distal end to a proximal end, where the sleeve member further includes a cutting edge along a portion of the proximal end; where the suture positioning assembly is slidably engaged within the sleeve member to selectively cut the suture segments. 
         [0017]    In some embodiments the first jaw member extends along the first jaw axis without a flange, and the second jaw member includes a flange extending transverse to the second jaw axis in a direction at least partially towards the first jaw member. In some embodiments, the flange extends beyond a distal end of the first jaw, and, when the grasp assembly is in the second state, the distal end of the first jaw rests against a surface of the flange facing the distal end of the first jaw member. In some embodiments, when the grasp assembly is in the second state, an end of the flange distal from the second jaw axis rests against a surface of the distal end of the first jaw member facing the second jaw member. 
         [0018]    In some embodiments, the grasp assembly includes an anchor adapted to receive the suture segments, the jaw members are adapted to captively hold and position the suture segments and the anchor between the first and second jaw members when the grasp assembly is in the second state; and the weld controller is selectively operative when the grasp assembly is in the second state and the compression and weld assembly is in the weld state, to apply energy to the heating element, whereby the heating element has a temperature above a predetermined threshold adapted to at least partially melt the anchor captively held between the jaws. In some embodiments, the anchor is a bone anchor. 
         [0019]    In some embodiments, the elongated tube is adapted to be received in an endoscopic surgical field. 
         [0020]    In another aspect, disclosed is a suture welding device, including an elongated tube extending along a central axis between a proximal end and a distal end, a suture positioning assembly affixed to the distal end of the tube. The suture positioning assembly includes: a hooked jaw member extending along a jaw axis from a proximal end and a distal end, and including a hooked flange portion at the distal end extending transverse to the jaw axis, the hooked flange portion being substantially curved and of sufficient length to provide a welding surface against which suture segments-to-be-welded may be compressed during welding. The hooked jaw member is adapted to captively hold and position the suture segments-to-be-welded against the welding surface. The device also includes an elongated joiner element extending along the central axis between a proximal end and a distal end, the joiner element having a selectively operative heating element disposed at the distal end of the joiner element; a compression and weld assembly operative to translate the joiner element along the central axis whereby in a first preparatory state, the distal end of the joiner element is relatively far from the welding surface, and in a weld state, is relatively near and biased toward the welding surface; and a weld controller selectively operative when the compression and weld assembly is in the weld state, to apply energy to the heating element, whereby the heating element has a temperature above a predetermined threshold adapted to at least partially melt the suture segments captively held against the welding surface. 
         [0021]    In another aspect, a method of suture welding is disclosed which includes: receiving suture segments between first and second jaw members, the first and second jaw members being in an open state. closing the first and second jaw members to captively hold and position the suture segments between the first and second jaw members; selectively applying an elongated joiner element to the suture segments where the joiner element has a selectively operative heating element facing the suture segments; and applying energy to the heating element to weld the suture segments-to-be-welded, whereby the heating element has a temperature above a predetermined threshold adapted to at least partially melt the suture segments. 
         [0022]    Some embodiments include aligning two or more of the suture segments side by side. In some embodiments, the first and second jaws are disposed at an end of an elongated tube having a central axis; the suture segments comprise two suture segments; and the closing the first and second jaw members to captively hold and position the suture segments between the first and second jaw members includes positioning the two suture segments with the two suture segments being side-by-side transverse the central axis, side-by-side along the central axis, or side-by-side along an axis oblique with respect to the central axis. 
         [0023]    Some embodiments include, after closing said first and second jaw members to captively hold and position the suture segments between said first and second jaw members, tensioning one or more of the suture segments. 
         [0024]    Some embodiments include, after applying energy to said heating element to weld the suture segments, cutting a portion of one or more of the suture segments. 
         [0025]    In some embodiments, selectively applying a joiner element to the suture segments includes compressing the suture segments between said joiner element and a surface of said jaw members 
         [0026]    Various embodiments may include any of the above described features, alone or in any combination. These and other features will be more fully appreciated with reference to the following detailed description which is to be read in conjunction with the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Embodiments are further described by the following description and figures, in which: 
           [0028]      FIG. 1  is a schematic view of an exemplary thermal suture welding apparatus of the present invention; 
           [0029]      FIG. 1A  is a schematic view of the distal end of the compression and weld assembly of the thermal suture welding apparatus of  FIG. 1 ; 
           [0030]      FIG. 2  is a perspective view of an embodiment of the jaw assembly portion of the thermal welding suture apparatus of  FIG. 1   
           [0031]      FIG. 2A  is a side plan view of the jaw assembly of  FIG. 2  in a first, load position; 
           [0032]      FIG. 2B  is a side plan view of the jaw assembly of  FIG. 2  in a second, tension position; 
           [0033]      FIG. 2C  is a side plan view of the jaw assembly of  FIG. 2  in a third, companion weld position; and 
           [0034]      FIG. 2D  is a side plan view of the jaw assembly of  FIG. 2  in a fourth, cutting position. 
           [0035]      FIGS. 3-7  are side plan views of alternative embodiments of the jaw members; 
           [0036]      FIG. 8A  is a cross-sectional side view of two suture segments-to-be-joined, aligned adjacent each other within the suture positioning assembly of the apparatus of  FIG. 1  where the two suture segments are disposed along the central axis of the elongate tube of the thermal welding suture apparatus; 
           [0037]      FIG. 8B  is a cross-sectional side view of two suture segments-to-be-joined, aligned adjacent each other within the suture positioning assembly of the apparatus of  FIG. 1  where the two suture segments are disposed along an axis transverse to the central axis of the elongate tube of the thermal welding suture apparatus; and 
           [0038]      FIG. 8C  is a cross-sectional side view of two suture segments-to-be-joined, aligned adjacent each other within the suture positioning assembly of the apparatus of FIG.  1 , where the two suture segments are disposed along an axis oblique with respect to the central axis of the elongate tube of the thermal welding suture apparatus. 
           [0039]      FIG. 9A  is a schematic view of an alternative embodiment of the thermal suture welding apparatus, having a bone anchor held within the grasper assembly. 
           [0040]      FIG. 9B  is a schematic view of the embodiment of the thermal suture welding apparatus, having a bone anchor held within the grasper assembly and beyond the end of the jaws. 
           [0041]      FIG. 9C  is a schematic view of the thermal suture welding apparatus, having a bone anchor held within the grasper assembly and for use with a single suture segment. 
           [0042]      FIG. 10A  is a schematic view of the thermal suture welding apparatus, having hook elements in an extended, deployed position. 
           [0043]      FIG. 10B  is a schematic view of the thermal suture welding apparatus as shown in  FIG. 10A , having hook elements in a retracted position. 
           [0044]      FIG. 11A  is a schematic view of the thermal suture welding, having an outer sleeve rotary cutter in its retracted position. 
           [0045]      FIG. 11B  is a schematic view of the thermal suture welding apparatus as shown in  FIG. 11A , showing the rotary cutter in its extended position. 
           [0046]      FIG. 11C  is a schematic view of the thermal suture welding apparatus as shown in  FIG. 11B , showing the rotary cutter in its extended position and rotated approximately 45 degrees about the central axis to cut a suture extending laterally between the jaw. 
       
    
    
       [0047]    Like reference numerals refer to like elements throughout the figures. 
       DETAILED DESCRIPTION 
       [0048]    As shown in  FIGS. 1 ,  1 A, and  2 , an exemplary thermal suture welding apparatus  10  includes an elongate tube  12  extending from a proximal end PE T  to a distal end DE T  along a central axis A. The tube  12  contains therewithin a portion of a compression and weld assembly  14  (not shown in  FIG. 1 ) and is coupled to a suture positioning assembly  16  at the distal end DE T  of tube  12 . A user activation/handle activation assembly  11  is affixed to the proximal end PE T , of tube  12 . The tube  12  may be substantially rigid or flexible, depending upon the anticipated surgical use of the apparatus  10 . Many biocompatible materials, or materials coated with a biocompatible coating may be used to manufacture the tube  12  and suture positioning assembly  16 , including, for example polyetheretherketone, polyphenylene sulfide, polyetherimide, and other polymers. Coatings may contain PTFE, polyimide, epoxies, alumina, silicon carbide, ceramics, and gold, titanium, or other metalized coatings. In an embodiment, the tube  12  is manufactured from stainless steel for a rigid tube  12 , or from nitinol or thermoplastics for a flexible tube. 
         [0049]    In an embodiment, the compression and weld assembly  14  comprises an actuation lever  11 A (and associated mechanical coupling, not shown on the activation assembly  11 ), and elongate tube  12  (including therein, a joiner element  18  and a heater  26 ). As shown in  FIG. 1A , the joiner element  18  is an elongated rod which may have a heater  26  supported thereon at its distal end. The joiner element  18  is slidably movable along the central axis A of the tube  12  within a channel  13  in tube  12  in response to user-applied forces (via lever  11 A of actuation assembly  11 ). The joiner element  18  is adapted to be selectively driven toward distal end DE T  of tube  12  to compress and weld (via heater  26 ) suture segments (not shown) held in place near the distal end DE T  by the suture positioning assembly  16 , as described in detail below. 
         [0050]    The joiner element  18  preferably is manufactured from stainless steel hypodermic tubing, but may be manufactured from any material that provides sufficient strength to bias the heating element  26  against the suture segments-to-be-welded (not shown) as supported by an anvil-like surface (not shown) created by jaw flanges, as described in further detail below. Typically, the range of compression is between 1500 psi and 6000 psi of clamping pressure against the suture segments. 
         [0051]    In an embodiment, and as shown in  FIG. 2 , the joiner element  18  includes heater  26  positioned on a heater substrate  28 . In this embodiment, heater  26  is resistively heated by electrical current driven therethrough, applied via wires (not shown) extending from proximal end PE T  of tube  12 . The voltage used for driving the current is controlled by an external heater controller  20  that may be user controlled or computer controlled. Alternatively, the voltage may be controlled using a switched internal current source (such as a battery). 
         [0052]    The heater element  26  preferably is manufactured from a biocompatible material (or material coated with a biocompatible material). Preferably, heater  26  has a positive thermal coefficient of resistivity (TCR). A suitable material is, for example, gold, or gold plated silver, but alternative materials may include silver, copper, platinum, nickel, or nickel iron. With that configuration, the heater  26  may be used as a heat source (to effect the thermal weld) and at the same time be used as a temperature sensor. The temperature sensor aspect of heater  26  has a resistance value which is fed back to the controller  20  (for example, in a bridge network), where it is used to control the current applied to heater  26 , so that a desired temperature-over-time profile may be provided with high precision, in a closed loop manner. The substrate  28  may be a ceramic material, such as alumina (A 2 O 3 ) that acts to thermally isolate the heater  26  so that precise temperature control can be attained. In some embodiments, the substrate  28  may be a polyimide. 
         [0053]    In response to user action on lever  11 A, the joiner element  18  may be slidably positioned within the elongate tube  12  for selectively and compressively driving the heater  26  against the suture segments-to-be-welded once such segments are positioned in the suture positioning assembly  16 , as described further below. In alternative embodiments, one or more heaters may be disposed on various surfaces of the suture positioning assembly, rather than on the distal end of joiner element  18 . Positioning of the joiner element  18  will vary depending on the configuration of the suture positioning assembly, the anticipated use of the apparatus  10 , and other similar variables. 
         [0054]    As shown in the illustrated embodiment of  FIGS. 1 and 2 , a suture cutting assembly  22  is disposed near distal end DE T  of tube  12 . Suture cutting assembly  22  includes movable (along axis A) blades  34 A and  34 B disposed on opposite sides of tube  12 . The blades are operable in conjunction with associated blade windows  40 A (only one window shown) near the distal end DE T  of tube  12 . 
         [0055]    The blades  34 A,  34 B are movable along axis A in response to user force applied to cutter control  22 A on activation assembly  11 . For deployment to a cutting position, the user applies a force to cutter control  22 A toward the distal end DE T  and along beveled surfaces  43 A (and  43 B) in tube  12  to a cutting position as shown in  FIG. 2D . 
         [0056]    As described in further detail below, when the suture segments-to-be-welded  51 ,  52  are securely positioned in the suture positioning assembly  16 , and then welded together, the cutting edge  42 A,  42 B of blades  34 A,  34 B trim off excess suture material from the welded suture loop (not shown). 
         [0057]    The joiner element  18  is used as a compression element, such that the compression of the suture segments-to-be-welded  51 ,  52  against an anvil-like surface  48  (as shown in  FIGS. 2B and 2C ) occurs while the heating element  26  is positioned against the suture segments-to-be-welded  51 ,  52  in a manner that simultaneously applies pressure and heat to the target suture segments. As melting begins to occur (as a result of the applied heat), the compressive force biases the melting suture segments  51 ,  52  toward each other, co-mingling the adjacent segments, to effect an optimum geometry of the ultimately welded suture segments. 
         [0058]    The suture positioning assembly  16  is affixed to the distal end DE T  of the elongate tube  12 , and generally comprises a pair of opposing jaws  32 ,  33 , and a grasp assembly  44  (internal to tube  12 ) for selectively moving the jaws  32 ,  33  in scissors-like opposition to each other for captively positioning and holding the suture segments-to-be-welded  51 ,  52  between the jaws (or at least against an anvil-like surface formed by the jaw flanges  46 ,  47 , as discussed in further detail below), in a position for welding. The jaws  32 ,  33  preferably are manufactured from a rigid biocompatible, material such as polyetheretherketone, polyphenylene sulfide, polyetherimide, and other polymers. In alternative embodiments, one or more of the jaws  32 ,  33  may be manufactured from a biocompatible plastic or metallic resilient material coated with an insulator, such as an elastomer of sufficient rigidity to enable a desired compression during the application of the heat necessary for satisfactory suture welding. The jaws  32 ,  33  extend along respective ones of jaw axes  32 A and  33 A. In some embodiments, jaws  32 ,  33  are rigid and in other embodiments, one or both jaws  32 ,  33  are flexible. 
         [0059]    In an embodiment, and as shown in  FIG. 2 , the jaws  32  and  33  are split anvil shaped, each jaw having a flange  46 ,  47 , respectively, extending transverse to jaw axes  32 A,  33 A for both securing the suture segments-to-be-welded  51 ,  52  and for providing, when in a closed position, a surface (or “anvil”  48 ) against which the compression joiner element  18  may compress the suture segments-to-be-welded  51 ,  52  during welding. In the illustrated embodiment, the flanges  46 ,  47  are extend perpendicular to the jaw axes  32 A,  33 A and are integral with and rigidly attached to the jaws. 
         [0060]    Alternative embodiments of the jaws  32 ,  33  are shown in  FIGS. 3-7 . In  FIG. 3 , the flanges  46 ,  47  are similar to those shown in  FIG. 2  except that they are at oblique angles to jaw axes  32 A and  33 A. When positioned in a closed position, the flanges  46  and  47  form an angled anvil surface (not shown) against which the suture segments-to-be-welded are compressed during welding. In an alternative embodiment, shown in  FIG. 4 , the jaws  32 ,  33  do not have flanges, but are curved in a bow-like manner toward each other, such that when closed, the distal ends of the jaws  32 ,  33  close to form the anvil surface  48  against which the sutures-to-be-welded are compressed during welding. In this embodiment, the jaws material preferably is of a rigid material to ensure that the jaws remain securely closed during welding and are not pushed apart during compression of the suture segments-to-be-welded. 
         [0061]      FIGS. 5 and 6  show alternative embodiments of the jaws  32 ,  33  whereby the bottom jaw  33  extends along the jaw axis  33 A without a flange, and the upper jaw  32  includes a flange  46 . In the illustrated embodiment of  FIG. 5 , the flange  42  extends beyond the distal end of the bottom jaw  33  such that the flange  46  forms the anvil surface against which the suture segments-to-be-welded are compressed during welding. In the illustrated embodiment of  FIG. 6 , the distal end of the flange  46  rests against the inner surface of the distal end of the bottom jaw  33 , again forming the anvil surface  48  against which the suture segments-to-be welded are compressed during welding. Although the illustrated embodiments of  FIGS. 5 and 6  show the bottom jaw  33  without a flange and the upper jaw  32  having a flange  46 , the inverse configuration also may be used. That is, the bottom jaw  33  may include a flange  47  while the upper jaw  32  is a straight jaw extending in the direction of the central axis A without a flange. 
         [0062]    In yet another embodiment of the suture positioning assembly  16 , as shown in  FIG. 7 , only a single jaw  32  is used. This illustrated jaw  32  has a flange  46  positioned integral to or attached to the distal end of the jaw  32 . This illustrated flange  46  is substantially curved and of sufficient length to provide the surface against which the suture segments-to-be-welded are compressed during welding. 
         [0063]    Each of these suture positioning assemblies  16  may be used together with the compression and weld assembly  14  to form the apparatus  10  of the present invention, and may be manufactured using the materials described above. 
         [0064]    The grasper assembly  44  of the apparatus  10  comprises lever  11 A, jaws  32  and  33  and an intermediate mechanical linkage (for example of a conventional type). In the configuration of  FIGS. 1 and 2 , the grasper assembly  44  is responsive to user control (via lever  11 A) at activation assembly  11  to selectively control jaws  32 ,  33  to be between open and closed positions. With lever  11 A in a first position (POS 1  in  FIG. 1 ), the jaws are in an “open” position, jaws  32 ,  33  are in a relatively divergent first state with their distal ends (and respective axes  32 A,  33 A) separated as shown in  FIG. 1 . Position POS 1  is referred to as a “load” position where suture segments-to-be-welded can be loaded between jaws  32 ,  33  for subsequent welding. POS 1  is illustrated in  FIG. 2A . 
         [0065]    With lever  11 A in a second position (POS 2  in  FIG. 1 ), the jaws are in a “closed” position wherein, jaws  32 ,  33  are in a relatively non-divergent second state with their distal ends close or touching POS 2  is referred to as a tension position wherein the suture segments-to-be-welded (not shown) can be tensioned by drawing the ends thereof around cleats  11 B using a rapid advance tensioning central  11 C on assembly POS 2  is illustrated in  FIG. 2B . 
         [0066]    With lever  11 A in a third position (POS 3  in  FIG. 1 ) the jaws  32 ,  33  are also in their closed position, and the joiner element  18  (and heater  26 ) are maximally displaced toward distal end DE T  and biased against the anvil-like surface  48  of the closed jaws  32 ,  33 . 
         [0067]    POS 3  is referred to as the “compression/weld/cut” position. In this position, suture segments-to-be-welded, which have been loaded and captured between jaws  32 ,  33 , are compressed and welded by joiner element (illustrated in  FIG. 2C ) and subsequently, the excess suture material is cut via cutter  22 ′ (illustrated in  FIG. 2D ). 
         [0068]    In an embodiment, the grasper assembly  44  and suture positioning assembly  16  are movable along central axis A, so that when the jaws  32 ,  33  are in their open position (as shown in  FIG. 1 ), the jaws  32 ,  33  are almost entirely beyond the distal end DE T  of tube  12  and when the jaws  32 ,  33  are in their closed position, the jaws  32 ,  33  are retracted and are almost entirely within the tube  12 . 
         [0069]    Also, when the distal end, DE T  of tube  12  is deployed to a surgical site, the jaws  32 ,  33  can be in their retracted position so as to minimize the cross-sectional dimensions of suture positioning assembly  16  at the distal end DE T  of tube  12 . 
         [0070]    In an embodiment of the invention, the suture segments-to-be-welded are manufactured from materials that enable the segments to be welded together. These materials may include polyester, Kevlar, nylon or polyethylene, by way of example. In an alternative embodiment, the suture segments may be welded to a surface treated with a material that enables the suture segments to be welded thereto. In practicing that embodiment, and by way of example, the suture segments may be welded to the surface of a bone anchor, which surface is treated with a material that enables such welding. Examples of materials that may be used in this embodiment include polyester, Kevlar, nylon or polyethylene. 
         [0071]    In practicing the present invention, the surgeon prepares the suture segments-to-be-welded either by knotting or merely overlapping such suture segments. The sutures may be prepared so that the segments-to-be-welded may be readily aligned with their respective central axes parallel. In practice, for example, following such preparation, the user would use the apparatus  10  of the invention to initially grasp and captively hold the aligned (and adjacent) suture segments-to-be-welded  51 ,  52  between jaws  32 ,  33  so as to be in one of many orientations. For example, the aligned suture segments may be disposed with their central axes  51 A,  52 A along an axis A 1  parallel to central axis A of tube  12 , as shown in  FIG. 8A . Alternatively, as shown in  FIG. 8B , two segments of suture may be aligned with their central axes  51 A,  52 A disposed along an axis A 2  which is transverse to the central axis A or, as shown in  FIG. 8C , with their central axes  51 A,  52 A disposed along an axis A 3  which is oblique with respect to the central axis A. The specific alignment of the suture segments  51 ,  52  may depend on user preference or constraints imposed during surgery. In various embodiments, the heater element  26  may be disposed on the distal end of the tube  12  as shown in  FIGS. 1 ,  1 A and  2 , or there may be heater elements on various interior surfaces of the jaws  32 ,  33 . 
         [0072]    Once the suture segments-to-be-welded  51 ,  52  are prepared for alignment (for example, by ensuring the segments-to-be-welded  51 ,  52  are in the desired general vicinity and with appropriate length and tension), the thermal welding apparatus  10  is moved into position in close proximity and adjacent to the suture segments  51 ,  52 . As shown in  FIG. 2A , the grasp assembly  44  is activated to position the jaw members  32 ,  33  in a first state wherein the distal ends of each jaw member  32 ,  33  are spaced apart sufficient to allow the introduction of the suture segments  51 ,  52  between the jaws  32 ,  33 . Once the sutures segments-to-be welded  51 ,  52  are positioned between the jaws  32 ,  33 , the jaws are positioned to their second state, wherein the distal ends of the jaws  32 ,  33  are close together to position and captively hold the suture segments  51 ,  52 , as shown in  FIG. 26 . Once in this position, with the suture segments-to-be-welded  51 ,  52  captively held, the user can draw on the respective ends of the suture to effect a desired tension, for example, using one or more cleats  11 B and tension control  11 C. 
         [0073]    In another embodiment, as shown in  FIG. 9A , an anchor  60  is placed in the grasper assembly  44 . The suture segments-to-be-welded  51 ,  52  are threaded through an aperture  62  in the proximal end of the anchor  60 , holding the segments  51 ,  52  in position. The anchor  60 , which may be a bone anchor, preferably is manufactured from a material that has material properties similar to the suture segments-to-be-welded  51 ,  52 . Such properties would allow the suture segments-to-be-welded  51 ,  52  to be positioned relative to and welded to the anchor  60  upon deployment of the heating element  26 . In this embodiment, the heating element  26  is mounted on the distal end of the joiner element  18  such that heat from the heater element  18  can be used to melt the top portion of the anchor member  60  into and around the suture segments  51 ,  52  to effect suture welding. The grasper assembly  44  is positioned to allow jaw members  32 ,  33  to contain the suture segments-to-be-welded  51 ,  52  and to fit the anchor  60  in close proximity to the segments  51 ,  52 . The external heater controller  20  then is selectively activated to heat the heating element  26  while the suture segments-to-be-welded  51 ,  52  are compressed against the anchor  60 . 
         [0074]    In another embodiment, the suture segments-to-be-welded  51 ,  52  may be threaded through an aperture  62  in the body of the anchor  60  prior to the introduction of the heating element  26 . In this embodiment, the grasper assembly  44  is positioned to allow jaw members  32 ,  33  to extend beyond the end of the jaw members  32 ,  33  to secure the anchor  60  in, for example, bone. Thus, the heater element  26  on the joiner element  18  is used to compress the suture segments-to-be-welded  51 ,  52 , using the bone into which the anchor  60  is secured to create the opposing force allowing compression without the use of jaw members  32 ,  33 . Once the anchor  60  is in position, and the suture segments-to-be-welded are sufficiently compressed, the external heater controller  20  is selectively activated to heat the heater element  26 , thus welding the suture segments  51 ,  52  to the anchor  60 . 
         [0075]    In yet another embodiment, and as shown in  FIG. 9C , the jaws  32 ,  33  hold an anchor  60  in place and a single suture  50  is positioned against the proximal surface of the anchor  60 . The anchor  60  is positioned in, for example bone, and the heater joiner element  18  is deployed against the suture  50  to melt the suture  50  against the proximal surface of the anchor  60 . 
         [0076]    As illustrated in  FIG. 2C , while the sutures are captively positioned in the suture positioning assembly  16 , the compression and weld assembly  14  is activated to slidably position the joiner element  18  such that the heater  26  is in contact with and biased against the outer surface of at least one of the suture segments  51 ,  52 . The weld controller  20  then is selectively activated to heat the heater  26  while the suture segments  51 ,  52  are compressed between the joiner element  18  and the opposing, interior surfaces of jaws  32 ,  33 . 
         [0077]    The welding is caused by heating heater  26  with a desired temperature-over-time profile, to a predetermined threshold temperature and for a threshold time that is sufficient to at least partially melt the portion of one suture segment that lies adjacent to another suture segment. This time and temperature profile will depend upon the type of suture used, including the diameter and materials of the particular suture. Other factors that may affect the time and temperature profile include the amount of moisture and body fluids present at the weld site. 
         [0078]    In practicing the present invention, the elongated material of the type used in surgical sutures can be a single filament, or substantially monofilamentous, and preferably polymeric. Typically, such sutures are manufactured from, but are not limited to, polymers, especially thermoplastic materials such as nylon, polypropylene, polyester (such as Dacron®), polyglycolic acid, polyglyconate, and polydioxanone. Alternatively, the suture may include multifilament forms, preferably braided, or may be of the type described and claimed in U.S. patent application Ser. No. 11/405,754. 
         [0079]    As shown in  FIG. 2D , after the suture segments  51 ,  52  are welded, the cutting element  22  is deployed. In an embodiment, the blades  34 A,  34 B are manually slid along the blade channels  36 A,  36 B by the user to move the sharp distal end of the blades  34 A,  34 B through the welded segments (not shown) at a point proximal to the welded suture joint. The apparatus  10  then may be retracted from the situs of surgery. 
         [0080]    In another embodiment, as shown in  FIG. 10A , the blades  35 A,  35 B may have a hook configuration, which may either upward (not shown) or downward (as shown in  FIG. 10A ). As shown, the hook blades  35 A,  35 B may be integral with or connected to the elongate tube  12 . In either configuration, the sharpened, cutting surface  38 A,  38 B of the blades  35 A,  35 B of this embodiment is located on the interior surface of the blades. Once the suture segments  51 ,  52  are welded as described above, the hook-shaped blades  35 A,  35 B may be distally deployed, thus capturing, the suture segments  51 ,  52  by the blades  35 A,  35 B as the hook travels over the extended suture segments. Then, by drawing the hook-shaped blades  35 A,  35 B back along the central axis A, the suture is pulled backward and cut as the sharpened interior surface  38 A,  38 B passes over the suture that is being held at the weld joint (not shown) within the joiner element and by the hook blades  35 A,  35 B.  FIG. 10B  shows the hook-shaped blades  35 A,  35 B in the retracted position. 
         [0081]    In another embodiment, as shown in  FIG. 10 , the cutting element  22  may be a portion of the distal end of a tube  62  which has a sharpened edge. Once the welding process is finished, the tube  62  is rotated, cleaving the suture between the sharpened edge of the tube and the suture positioning assembly  16 . 
         [0082]    In another embodiment of the invention, as shown in  FIG. 11A , an elongate sleeve  70  may be positioned over the elongate tube  12 . The sleeve  70  is configured such that a portion of the surface of proximal end of the sleeve is a sharpened edge  72 .  FIG. 11A  shows the jaws  32 ,  33  in a closed position as typical following suture welding. Once the suture welding is complete, the sleeve  70  is slidably positioned toward the proximal end of the apparatus  10 . In the illustrated embodiment of  FIG. 11B , the sleeve  70  is shaped such that when the sleeve  70  is fully deployed proximal to the grasper assembly  44 , the sharpened edge  72  is positioned above the ends of the suture (not shown) that extend from the grasper assembly  44 . The sleeve  70  then is rotated some degrees about central axis A, as shown in  FIG. 11C , to engage the sharpened edge  72  across the suture ends, thus severing the suture as the sleeve  70  rotates. The sleeve  70  may be moved into position prior to or following formation of the suture weld. 
         [0083]    In some embodiments, the welding apparatus  10  may include heating elements of the type described in U.S. Provisional Application Ser. No. 60/876,458, which incorporated above by reference in its entirety, or in U.S. patent application Ser. No. ______, entitled Heater Assembly For Suture Welder, and filed Dec. ______, 2007, which is incorporated herein by reference in its entirety. 
         [0084]    The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of the equivalency of the claims are therefore intended to be embraced therein.