Abstract:
A wound closure system and a method of closing a wound are disclosed. The disclosure is directed to a wound closure system comprising a skin anchor mechanically attached to external skin tissue on a first side of a generally linear wound, an anchorable tensioning apparatus mechanically attached to external skin tissue on an opposite side of the wound, and a line extending between the skin anchor and the tensioning apparatus to movably connect the anchor to the tensioning apparatus. The line is fixedly engaged with an anchor on one side of the wound while the tensioning apparatus provides tension on the line to draw the skin anchor and the tensioning apparatus toward each other and toward the wound.

Description:
TECHNICAL FIELD 
   The principles disclosed herein relate generally to wound closure by facilitating stretching of skin tissue. More specifically, the disclosure relates to a system and method of facilitating expanding the skin tissue over a wound by use of dynamic force. 
   BACKGROUND 
   Surgical procedures such as tumor removal or fasciotomies can result in large skin wounds. Chronic wounds such as diabetic ulcers frequently do not heal. Techniques have been developed to facilitate the wound closure of large skin defects and chronic wounds. 
   Common methods for closure of wounds and skin defects include split thickness skin grafting, flap closure and gradual closure utilizing tissue expansion. A split thickness skin graft involves removing a partial layer of skin from a donor site, usually an upper leg or thigh, and leaving the dermis at the donor site to re-epithelialize. In this manner, a viable skin repair patch can be transferred or grafted to cover the wound area. The graft is often meshed, (which involves cutting the skin in a series of rows of offset longitudinal interdigitating cuts) allowing the graft to stretch to cover an area two or three times greater than the wound, as well as provide wound drainage while healing. Normal biological function of the skin heals the cuts after the graft has been accepted. A meshed graft of this type requires a smaller donor area than a conventional non-meshed or full thickness skin graft. Flap closure involves transferring skin from an adjacent region to the wound. This technique is only effective in anatomical regions that are amenable to transfer of adjacent skin. It is also a more complex surgical procedure involving increased surgical costs and risks. Both of these methods do not provide optimal cosmesis or quality of skin cover. Other disadvantages of these methods include pain at the donor site, creation of an additional disfiguring wound, and complications associated with incomplete “take” of the graft. In addition, skin grafting often requires immobilization of the limb, which increases the likelihood of contractures. The additional operation and prolongation of hospital stay is an additional economic burden. 
   Gradual, or progressive, closure is another method of wound closure. This technique may involve suturing vessel loops to the wound edge and drawing them together with large sutures in a fashion similar to lacing a shoe. In addition, the wound edges may be progressively approximated with suture or sterile paper tape. The advantages of this gradual, or progressive, technique are numerous: no donor site is required for harvest of a graft; limb mobility is maintained; superior cosmetic result, more durable skin coverage, better protection because skin is full thickness, and maintenance of normal skin sensation may all be achieved. 
   Existing devices for effecting a gradual closure, however, have many disadvantages. Current methods and devices rely on static ribbon or suture material which must be repeatedly readjusted in order to draw wound edges together because a relatively small skin movement substantially eliminates much of the closure force. Even with constant readjustment, maintenance of near constant tension over time is difficult, if not impossible, to achieve. Since widely used existing closure techniques involve use of relatively inelastic materials such as sutures or surgical tape, a substantial amount of tension is put on the wound edges during periodic adjustment to obtain the necessary closure force. Excessive tension may cut the skin or cause necrosis due to point loading of the tissue. 
   What is needed in the art is a gradual wound closure technique that is self-regulating and self-adjusting and uses continuous or dynamic tension to draw the wound edges together, without obstructing the wound, thus eliminating the need for constant readjustment involved with the static systems. 
   SUMMARY 
   The principles disclosed herein relate to wound closure by facilitating stretching of skin tissue. The disclosure relates to a system and method of facilitating expanding the skin tissue over a wound by use of dynamic force. 
   The disclosure is directed to a wound closure system including components adapted to apply a dynamic tension force on a plurality of anchors that are attached to skin tissue surrounding a wound. The dynamic tension force draws the anchors toward the wound facilitating stretching of the skin tissue over the wound area. 
   In one particular aspect, the disclosure is directed to a wound closure system comprising a plurality of skin anchors mechanically attached to external skin tissue around a generally linear wound. The skin anchors are configured to pass a line extending between multiple skin anchors across the wound. A single line or multiple lines may be used. Application of tension to the line(s) draws the skin anchors toward each other and toward the wound. The tension is applied by a tensioning apparatus that is mechanically attached to the external skin tissue. 
   In another particular aspect, the disclosure is directed to a wound closure system comprising a plurality of skin anchors mechanically attached to external skin tissue on opposite sides of a generally linear wound, a line extending between the skin anchors to slidably connect the anchors, the line slidably engaged with at least one skin anchor, and a biasing member that provides tension on the line to draw the connected skin anchors toward each other and toward the wound. 
   In an alternate embodiment, the disclosure is directed to a wound closure system comprising a skin anchor mechanically attached to external skin tissue on a first side of a generally linear wound, an anchorable tensioning apparatus mechanically attached to external skin tissue on an opposite side of the wound, a line extending between the skin anchor and the tensioning apparatus to movably connect the anchor to the tensioning apparatus, the line fixedly engaged with the anchor, with the tensioning apparatus providing tension on the line to draw the skin anchor and the tensioning apparatus toward each other and toward the wound. 
   In yet another particular aspect, the disclosure is directed to a method of closing a wound, the method comprising the steps of mechanically attaching a skin anchor to external tissue on a first side of a generally linear wound, mechanically attaching an anchorable tensioning apparatus to external skin on an opposite side of the wound, extending a line between the skin anchor and the tensioning apparatus to movably connect the anchor to the tensioning apparatus, and providing tension to the line to draw the skin anchor and the tensioning apparatus toward each other and toward the wound. 
   In yet another particular aspect, the disclosure is directed to a wound closure kit comprising a skin anchor adapted for attachment to external skin tissue, a line adapted to be coupled to the skin anchor, an anchorable tensioning apparatus adapted for attachment to external skin tissue and adapted for providing tension on the line. 
   In yet another particular aspect, the disclosure is directed to an alternative use of the wound closure system where the wound closure system may be used for cosmetic purposes to stretch the skin at certain parts of the body that do not include wounds. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top perspective view of a wound closure system in accordance with the principles of the present disclosure, illustrating multiple stretching elements operably positioned in relation to a wound; 
       FIG. 2  is a top perspective view of one stretching element of  FIG. 1  illustrated alone, the stretching element having a skin anchor and an anchorable tensioning apparatus; 
       FIG. 3  is an exploded view of the tensioning apparatus of the stretching element of  FIG. 2 ; 
       FIG. 4  is an enlarged top perspective view of a biasing member of the tensioning apparatus of  FIG. 3 ; 
       FIG. 5A  is a top perspective view of a spool of the tensioning apparatus of  FIG. 3 ; 
       FIG. 5B  is a bottom perspective view of the spool of  FIG. 5A ; 
       FIG. 5C  is another bottom perspective view of the spool of  FIG. 5A ; 
       FIG. 6  is an enlarged top perspective view of a base of the tensioning apparatus of  FIG. 3 ; and 
       FIG. 7  is a top perspective view of an alternative embodiment of a wound closure system in accordance with the principles of the present disclosure, the wound closure system illustrated in combination with a cross-sectional view of the skin. 
   

   DETAILED DESCRIPTION 
   The inventive aspects of the disclosure will now be described by reference to the several drawing figures. The functional features of the inventive aspects can be embodied in any number of specific configurations. It will be appreciated, however, that the illustrated embodiments are provided for descriptive purposes and should not be used to limit the inventions described herein. 
   A. Wound Closure System 
     FIG. 1  illustrates a wound closure system  10  having features that are examples of inventive aspects disclosed herein. The wound closure system  10  illustrated in  FIG. 1  includes a plurality of stretching elements  120  (each individually indicated as  120   a ,  120   b  and  120   c ) generally positioned around the periphery of a wound  12 . Elements  120   a ,  120   b ,  120   c , etc. are attached to the skin surrounding wound  12  by mechanical means (e.g., staples). Each element  120  includes an anchor  125  (each individually indicated as  125   a ,  125   b ,  125   c ) and an anchorable tensioning apparatus  140  (each individually indicated as  140   a ,  140   b ,  140   c ). Anchors  125   a ,  125   b ,  125   c  are connected to anchorable tensioning apparatus  140   a ,  140   b ,  140   c  by a tension line  130  (individually indicated as  130   a ,  130   b ,  130   c ). 
   A single stretching element  120 , having anchor  125 , line  130  and anchorable tensioning apparatus  140 , is illustrated in  FIG. 2 . For ease of understanding, the inventive aspects of the following disclosure will be described with reference to only a single stretching element, it being understood that multiple elements can be utilized for the wound closure system within the spirit of the invention, as illustrated in  FIG. 1 . 
   Referring to  FIG. 2 , anchor  125  is connected to anchorable tensioning apparatus  140  by tension line  130 , which is fixedly attached to anchor  125  and to tensioning apparatus  140  in a manner as to extend across wound  12  (as illustrated in  FIG. 1 ). Anchorable tensioning apparatus  140 , which is attached to skin at the opposite side of the anchor  125 , is adapted to apply tension to line  130  to draw anchor  125  and the tensioning apparatus  140  inwardly toward each other, and, thus, the skin over the wound. Anchor  125  and tensioning apparatus  140  are positioned to generally linearly move toward each other. 
   An inelastic or non-stretchable line  130  is preferably used to draw skin anchor  125  and the tensioning apparatus  140  toward wound  12  since the tensioning apparatus  140  is adapted to provide the dynamic force needed for wound closure. An elastic line  130  can also be used, and may be preferred in some embodiments due to its ability to provide lessened tension and more flexibility. 
   In an alternate embodiment that is within the scope of this disclosure, an elastic line  130  alone that is fixedly attached to two anchors located on opposite sides of a wound can be used to provide the dynamic tension on the skin, without the use of a tensioning apparatus. 
   B. Anchorable Tensioning Apparatus 
   Referring to  FIG. 3 , tensioning apparatus  140  includes a base  160 , a spool  180  that seats on the base  160 , a biasing member  150  that is placed around the spool  180 , a connection rod  190  that extends axially through the tensioning apparatus  140 , and a cover  170  that is placed on the base  160  to enclose the individual components of the tensioning apparatus  140 . 
   Referring to  FIG. 4 , there is generally illustrated therein an enlarged view of the biasing member  150  of the tensioning apparatus  140 . The biasing member  150  is adapted to be mounted within tensioning apparatus  140  to provide the dynamic tension force on the skin anchor  125 . As the skin stretches and grows over wound  12 , anchor  125  moves toward apparatus  140  and toward wound  12 , reducing the tension on line  130  and creating “slack” on tension line  130 . Biasing member  150  provides the tension to take up the slack on line  130 . In certain embodiments, the tension force that is applied to each skin anchor  125  is usually at least 1 oz. and usually no greater than 64 oz., commonly between 4 and 16 oz. 
   The biasing member  150  is depicted essentially as a spring formed from a coiled-up metal band  151 . Although depicted as a coiled spring in  FIGS. 3 and 4 , biasing member  150  may include other structures. For example, biasing member  150  may include a constant-force spring designed to provide a constant level of tension on line  130  when it is in a loaded state. Biasing member  150  may alternatively include a nonconstant-force spring designed to provide varying amounts of force on line  130  depending upon how tightly it is wound. As one skilled in the art will appreciate, the force application characteristics of such springs depend upon factors such as the mechanical properties of the springs, the thickness, the diameter, etc. 
   It will be understood that biasing member may also refer to an elastic tension line that is extended across the wound and coupled to two skin anchors on opposite sides of the wound that is used to draw the anchors toward each other and toward the wound. 
   The band  151  defines an inner hook portion  152  and an outer tab portion  153 . The coiled up band  151  is positioned around an upper spring mount portion  182  of the spool  180  (see  FIGS. 5A-5C ) as will be discussed further below. When positioned as such, a portion of the hook portion  152  of the band  151  is placed within a slot  188  defined on the upper spring mount  182  of the spool  180 . The outer tab  153  of the band  151  cooperates with the cover  170  of the tensioning apparatus  140  to stay fixedly in a wound orientation. 
   Referring to  FIGS. 5A-5C , there is generally illustrated the spool  180  of the tensioning apparatus  140 . The spool  180  includes an upper spring mount portion  182 , a lower tension line mount portion  184 , and a main plate  186  separating the two portions. In this embodiment, all the portions of the spool  180  are depicted as integrally formed from one unitary piece. However, it will be appreciated that in other embodiments, the spool may be formed from multiple separate pieces that are coupled together. 
   The upper spring mount portion  182  has a generally cylindrical shape. The upper mount portion  182  includes a slot  188  adapted to receive the hook portion  152  of the biasing member  150  as discussed above. The spool  180  also includes a throughhole  106  for receiving the connection rod  190  used to couple the spool  180  to the base  160  of the tensioning apparatus  140 . 
   The lower tension line mount portion  184  defines a winding groove  185 . The winding groove  185  is defined between the main plate  186  and a lower seat plate  183 . The lower seat plate  183  provides structure for seating the spool  180  into the base  160  of the tensioning apparatus  140 . The spool  180  also defines a line attachment hole  187  that communicates with the winding groove  185  through a slit  189  defined within the winding groove  185 . Before being wound, one end of the tension line  130  is fed through the slit  189  into the hole  187  and a knot is tied to secure one end of the tension line  130  to the spool  180 , the knot being large enough that the end of the line  130  will not slip through the slit  189 . After being secured to the spool  180 , line  130  is wound around the spool  180  within the winding groove  185 . 
   Referring to  FIG. 6 , there is generally illustrated the base  160  of the tensioning apparatus  140 . Base  160  includes a generally circular main body  161 . Defined within the body  161  is an interior cavity  165  shaped to receive the lower seat plate  183  of the spool  180 . The base  160  includes a hole  164  defined within the interior cavity  165  for receiving the connection rod  190  used to couple the spool  180  to the base  160 . 
   Referring back to  FIG. 3 , there is generally illustrated therein the cover  170  of the tensioning apparatus  140 . The cover  170  generally includes an interior shape configured to fit around the exterior of the base  160 . The cover  170  includes a main body portion  171  and an elongate snout portion  172 . The main body portion  171  fits over the main body portion  161  of the base  160 . 
   The interior of the cover  170  (not shown in the FIGS.) is generally shaped and sized to receive the biasing member  150 . The interior of the cover  170  includes structure (not shown in the FIGS.) that cooperates with the outer tab portion  153  of the biasing member  150  to keep the biasing member wound up within the cover  170 . 
   The snout portion  172  of the cover  170  includes a hole for feeding an end of the tension line  130  out of the cover  170 , the other end of the tension line having been attached to the spool  180  located within the cover  170 . The front of the snout portion  172  includes an extended lip  175  which defines a ramped surface  176 . The ramped surface  176  is configured to cooperate with a tension line tab  128  of a skin anchor  125  to fixedly mount the cover  170  to a skin anchor  125 . As shown in  FIG. 3 , the ramped surface  176  is inserted within a tension line slot  129  defined by the tension line tab  128  of the skin anchor  125  as the tension line tab  128  abuts against the front of the snout  172 . With this feature, the tensioning apparatus  140  can be allowed to move with the anchor  125  as the skin is stretched toward the wound  12 . 
   It will be appreciated that, although the tensioning apparatus is depicted as a unit that is separate from the skin anchor that it is attached to, the tensioning apparatus may include an integrally formed anchoring means adapted to anchor the tensioning apparatus to external skin. 
   C. Skin Anchors 
   As seen in  FIG. 1 , anchors  125   a ,  125   b ,  125   c  are placed around the periphery of wound  12 . Each anchor  125  is mechanically fastened to the skin, such as by conventional medical skin staples. Suturing can also be used to mechanically attach anchors  125  to the skin. 
   Referring to  FIG. 2 , two skin anchors  125  of the stretching element  120  are generally illustrated therein. Each anchor  125  includes a first end  121 , a second opposite end  123 , and a generally rectangular body  124  defined between the first end  121  and the second end  123 . The anchor  125  includes two skin-penetrating barbs  122  proximate the first end  121  for securement to the skin. The barbs  122  preferably have a bearing surface with a large enough width perpendicular to the direction of the tension so that the barbs  122  do not cut through the skin when pulled toward the wound  12  in tension. In this manner, as the barbs  122  move in toward the wound, the skin moves with the barbs  122 . The barbs  122  can be bent at an angle A B  less than about 90 degrees from the skin surface. The barbs  122  can be bent, preferably, at about a 60 degree angle A B  to improve their ability to hold into the skin. The edges of the barbs  122  are sharp to make it easy to penetrate the skin upon insertion. Two pairs of indentations, generally indicated at  126 , are formed on opposite sides of the body  124  of the anchors to help guide where mechanical attachment, such as staples  102 , are to be placed. Two pairs of tabs  127  extending out from the opposing sides of the body  124  are adapted to abut against the staples  102  to pull the skin toward wound  12 . Although the guiding indentations  126  are located forward of the tabs  127 , as anchor  125  is pulled in toward wound  12 , the tabs  127  eventually abut against the staples  102  after initial stretching of the skin around the wound area is achieved. 
   The tension line tab  128  defines the tension line slot  129  formed at the first end  121  of the anchor  125  for receiving tension line  130 . The tension line slot  129  is formed with a wide lead-in area to make it easy to receive tension line  130 . The tension line slot  129  may be sized such that tension line  130  is “snapped-in” past the narrowest point of the slot  129  to prevent the line from accidentally being pulled out. 
   Still referring to  FIG. 2 , anchor  125  includes a length L A . The barbs  122  include a penetration depth D P . The inner edges of the barbs  122  are spaced apart a distance of W B . The dimensions, L A , D P , W B , and A B  can be varied according to desired skin anchor performance in different parts of the human body and for different types and ages of skin. 
   Table 1, below, illustrates two example configurations for the anchor, with two different sets of dimensions that are suitable for use with the stretching element  120 . Anchors with example configuration  1  are preferably retained by two conventional regular size medical skin staples (5.7 mm×3.9 mm). Anchors with example configuration  2  are preferably retained by two wide size medical skin staples (6.9 mm×3.9 mm). 
   
     
       
             
           
             
             
             
             
             
           
             
             
             
             
             
           
         
             
               TABLE 1 
             
           
           
             
                 
             
             
               Anchors (unless otherwise specified, all dimensions are in inches) 
             
           
        
         
             
                 
               L A   
               D P   
               W B   
               A B   
             
             
                 
                 
             
           
        
         
             
               Configuration 1 
               0.739 
               0.158 
               0.186 
               60° 
             
             
               Configuration 2 
               0.607 
               0.115 
               0.206 
               60° 
             
             
                 
             
           
        
       
     
   
   In a preferred embodiment, the anchor  125  is formed from stainless steel sheet such as  302  or  316  containing 8 to 14% nickel content. It will be appreciated that the anchors can be stamped with a progressive die, wire EDM-cut, shaped from metal, shaped from wire, injection molded, or made by other suitable methods. The anchors can also be manufactured from other metals such as titanium. 
   The barbs of the skin anchors described above could optionally include a hollow portion and an exit hole or aperture adapted to be exposed to the undersurface of the skin once the barb penetrates the skin. A medicinal component, such as anesthesia (such as “Lidocaine”) or an anti-bacterial material, may be applied through the hole and thus to the skin. Any such medicinal component may be provided by a continuous source, such as by being connected to an IV drip, or be applied when the anchor is attached to the skin. In this manner, the medicinal component can be supplied around wound area  12  through skin punctures that have been created by the barbs of the skin anchors. 
   D. Tension Line 
   Referring back to  FIG. 1 , tension line  130  of stretching element  120  is illustrated as being coupled to anchor  125  across wound  12 . Suitable examples for tension line  130  include nylon or polypropylene line, suture material, string, a cable, a wire, or other similar item. Line  130  should be sufficiently flexible and bendable to allow attachment to anchor  125 . In a preferred embodiment, tension line  130  is conventional suture material. One preferred line  130  is made from nylon and has a tensile strength of about 6 lbs to 10 lbs. Tension line  130  preferably includes a thread diameter of about 0.5 mm to 0.6 mm. 
   Although depicted as including a separate tensioning apparatus in  FIGS. 1 and 2 , the stretching element  120  may instead utilize a line  130  that includes elastic material to provide the dynamic tension on skin anchors  125 . This elastic line may also be referred to as a biasing member that provides the tension needed to pull the anchors toward each other and the wound. With the use of a tensioning apparatus such as  140 , however, an inelastic line can be utilized to draw skin anchors  125  toward wound  12  since the tensioning apparatus is adapted to provide the dynamic force needed for wound closure. An elastic line can also be used in addition to a separate tensioning apparatus. 
   E. General Use of Wound Closure System 
   General assembly and use of the system will be described with reference to  FIGS. 2 and 3 . In general use, first, the skin anchors  125  are placed at the opposing sides of a generally linear wound (see  FIG. 1  for wound  12 ). After penetrating the skin by pressing the skin engagement barbs  122  of the anchors  125  into the skin, skin anchors  125  may then be further coupled to the skin with the use of, for example, staples  102 . The two pairs of indentations  126  defined on the body  124  of skin anchor  125  serve as target areas for placement of the staples  102 . 
   After one end of the tension line  130  has been secured to the spool  180  and the line wound around the spool, the tensioning mechanism  140  may be assembled with the spool  180  fitting into the base  160 . The free end of the line  130  is guided out of the snout portion  172  of the cover  170 . The biasing member  150  is placed on top of the spool  180 , and the cover  170  is mounted on top of the base  160  enclosing the tensioning apparatus  140 . 
   After assembly of the tensioning apparatus  140 , a loop is tied at the free end of the line  130  that is fed out of the snout portion  172  of the cover  170 . The loop is placed around the tension line tab  128  of the anchor  125  on one side of the wound. Then, the tensioning apparatus  140  may be pulled across the wound and attached to the anchor at the opposite side of the wound, with the biasing member  150  in a wound-up orientation. As anchors  125  move in toward each other and toward the wound by the stretching of the skin, the wound-up biasing member  150  and hence the spool  180  keeps line  130  taut. As mentioned above, depending on the size and shape of the wound, one or more stretching elements may be utilized as part of the wound closure system. 
   The tensioning apparatus  140  may be easily removed from the anchor  125  by holding the line  130  and pulling the tensioning apparatus back away from the anchor that it is attached to. 
   F. Alternative Embodiment of Wound Closure System 
   Referring to  FIG. 7 , in an alternate configuration of a wound closure system  110  according to the present disclosure, skin anchors  225  (including features similar to anchors  125  of  FIGS. 1 and 2 ) can be placed under the dermis  11 . In the configuration of the wound closure system  110 , the edges of a wound, such as wound  12 , would be undermined and then the skin anchors  225  would be inserted between the muscle layer  13  and the subcutaneous fat layer  15 . A line  230  from a tensioning apparatus  240  (line  230  and tensioning apparatus  240  including features similar to line  130  and tensioning apparatus  140  described above, respectively) would be attached to the skin anchors  225 . The tensioning apparatus may include a rigid conduit  261  through which line  230  may pass, the conduit  261  running from a snout portion  272  of a cover  270  of the tensioning apparatus  240  to the middle of the wound  12 . The rigid conduit  261  may be similar to a force guide tube disclosed in pending patent application Ser. No. 10/949,115 filed on Sep. 13, 2004, the disclosure of which is incorporated herein in its entirety. The rigid conduit  261  provides structural support for the line  230  and allows the tensioning apparatus  240  to be positioned at a remote location from the wound  12 . The rigid conduit provides a way to concentrate the pulling force of the tensioning apparatus  240  into a single point at the center of the wound  12 . 
   The sub-dermal skin anchors  225  may be made from any suitable material and may include features similar to skin anchors  125 . A preferred design is to have the skin anchor  225  made from stainless steel and having four skin engagement barbs  222  bent at an angle, such as 60 degrees. 
   In general use, to insert the skin anchors  225 , the physician would undermine the skin along the edge of the wound  12 . The subcutaneous fat layer  15  would be spread from the muscle layer  13  and the skin anchor  225  would be inserted therebetween. The skin engagement barbs  222  would then engage into the subcutaneous fat  15  and the dermis  11 . The skin engagement barbs  222  are preferably angled so that as more force is applied to the tension line  230 , the anchors  225  are pulled further into the dermis  11 . 
   In another embodiment of the skin anchors, the skin engagement barbs can be configured to pivot. The barbs could be configured such that the barbs would go from a flat position to an angled position via a pivoting structure such as a hinge. When first inserted into the skin, the skin engagement barbs would be flat or parallel to the surface of the skin anchors and as the anchors are pulled toward the wound by the tensioning apparatus  240 , the barbs would pivot up and start penetrating the subcutaneous fat layer  15  and the dermis  11 . An advantage of this design would be that it would not be necessary to spread the subcutaneous fat layer  15  from the muscle layer  13  as the skin anchors would be easy to slide in between the two layers. When tension is applied to the tensioner line  230 , the skin engagement barbs would pivot until a stop position is encountered. This stopping position could be provided at such a point that an angle of 60 degrees or a similar angle from parallel is achieved. The skin engagement barbs would then dig into the dermis and start stretching the skin as force is applied to the tension line  230 . 
   In another embodiment of the sub-dermal skin anchors, the skin anchors could be made from an absorbable material, that is, a material that is absorbed by body fluids. Such a design has the advantage of not needing to remove the skin anchors after the skin has stretched adequately to close the wound. The anchors would just be left under the dermis and gradually dissolve. 
   It should be appreciated that the wound closure system  110  utilizing sub-dermal skin anchors  225  can be used with a linear wound closure system such as one described in the present disclosure or could be used with a radial wound closure system such as one described in the pending patent application Ser. No. 10/949,115 filed on Sep. 1, 2004. In a linear system, the line  230  coming out of the tensioning apparatus  240  would be split into two ends, each end being coupled to opposing skin anchors  225  to draw the skin anchors toward each other. In a radial system, a single line in the form of a loop can be coupled to anchors placed around the wound as described in further detail in pending application Ser. No. 10/949,115. 
   G. Alternative Use of Wound Closure System 
   The wound closure system may be used to stretch the skin for purposes other than for wound closure. One such example use of the wound closure system is directed to improving the cosmetic effects of male-pattern baldness. For example, the skin anchors may be placed on the human scalp such that the tension line extends across the so called “bald-spot.” The tensioning apparatus or an elastic tension line, for example, then, may be used to gradually draw the skin anchors toward each other to stretch the skin with the hair follicles surrounding the bald-spot to eventually reduce the size of the bald-spot. 
   From the foregoing detailed description, it will be evident that modifications and variations can be made in the devices of the invention without departing from the spirit or scope of the invention. Therefore, it is intended that all modifications and variations not departing from the spirit of the invention come within the scope of the claims and their equivalents.