Patent Publication Number: US-7708746-B2

Title: Method and apparatus for processing dermal tissue

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. application Ser. No. 10/789,620, filed Feb. 27, 2004, which claims the benefit of U.S. Provisional Patent Application No. 60/450,375, filed Feb. 27, 2003, the disclosure of each is incorporated herein by reference as if set forth in its entirety. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a method and apparatus for processing dermal tissue that has been harvested from a patient and, in particular, relates to a method and apparatus for cutting and mincing dermal tissue into particles suitable for transplantation into a wound on the patient. 
   Skin grafting has traditionally involved the removal of a thin slice of dermal tissue from a donor site on a patient. The slice of tissue is then used to cover the site of a wound, which is typically a non self-healing wound or a burn. In some cases the tissue is processed before it is applied to the recipient wound site. A common process called meshing creates a number of small, non-connected cuts in the slice of tissue. The tissue can then be stretched until it has the appearance of a mesh or net. In this state, it can cover a larger area of a wound. Other methods of processing include cutting the tissue into particles with knives, blades or scissors. 
   The purpose of such processing is to use tissue from a donor site to cover a wound area that is larger than the donor site. The ratio of the wound area to the donor site area is called the expansion ratio. A higher expansion ratio is desirable to minimize the trauma of the donor site, and to aid patients who have only a small amount of dermal tissue available for grafting purposes. 
   Traditional methods of processing dermal tissue have produced low expansion ratios. They have also produced poor cosmetic outcomes in which the healed wound exhibits a rough and uneven surface. 
   Another device utilizes a drum carrying a plurality of parallel blades that is supported above a cutting surface. A strip of tissue is placed on the cutting surface, and the device is activated to rotate the drum and bring the blades into contact with the underlying cutting surface. The tissue is manually translated across the cutting surface to enable the blade to slice the tissue into fine strips. The strips of tissue can then be repositioned on the cutting surface to enable the blades to cut the strips into individual particles. Unfortunately, particles may accumulate in the interstices between adjacent blades and need to be manually removed using a spatula or the like. Furthermore, because the position of the blade is stationary relative to the cutting surface, the cutting operations may be rigid and difficult to perform. 
   It would therefore be desirable to provide a simpler processing device that is inexpensive, disposable and easy to use compared to conventional devices. It would be further desirable to achieve higher expansion ratios than conventionally achieved in order to improve cosmetic outcomes for healed wounds. 
   BRIEF SUMMARY 
   In accordance with a first aspect of the invention, an apparatus for processing harvested dermal tissue supported on a cutting surface includes a housing that presents a handle having a gripping surface and a cutting head attached. A cutting assembly is connected to the cutting head. The cutting assembly includes a plurality of spaced apart blade tips spaced apart a distance between about 100 μm and about 5000 μm and configured to cut through the harvested tissue when the cutting assembly rotates along the cutting surface to produce sliced tissue. A receptacle is disposed downstream of the cutting assembly such that the receptacle receives the sliced tissue from the cutting blades. 
   In some embodiments, the apparatus further includes a base supported by the housing and a plurality of tines extending outwardly from the base, which are configured to interdigitate between adjacent blade tips. The tines remove sliced tissue lodged in the cutting assembly. 
   In some embodiments, the blade tips are spaced apart a distance between about 750 μm and about 850 μm. 
   In some embodiments, the sliced tissue presents an edge dimension between about 500 μm and about 900 μm. In other embodiments, the sliced tissue presents an edge dimension between about 750 μm and about 850 μm. 
   In accordance with a second aspect of the invention, a method for processing harvested dermal tissue supported on a cutting surface using a device having a housing that supports a cutting assembly including a plurality of spaced apart cutting blade tips includes a first step of bringing the blade tips into contact with harvested tissue having a thickness between about 130 μm and about 840 μm, such that the blade tips engage the cutting surface. The method includes a second step of translating the device along the cutting surface in a first direction to cut through the tissue to produce sliced tissue. 
   In some embodiments, the method generates sliced tissue having an edge dimension between about 100 μm and about 5000 μm. In other embodiments, the sliced tissue has an edge dimension between about 200 μm and about 1200 μm. In still other embodiments, the sliced tissue has an edge dimension between about 500 μm and about 900 μm. In preferred embodiments, the sliced tissue has an edge dimension between about 750 μm and about 850 μm. 
   In some embodiments, the method includes additional steps of placing the sliced tissue back onto the cutting surface, of bringing the cutting blades into contact with the sliced tissue such that the cutting blades engage the cutting surface, and of translating the device along the cutting surface in a second direction different than the first direction to cut through the sliced tissue and produce further sliced tissue. 
   In some embodiments, the method employs harvested tissue having a thickness between about 260 μm and about 450 μm (which can be obtained using, e.g., a dermatome), and sliced tissue having an edge dimension (i.e., length or width) each between about 100 μm and about 5000 μm. In other embodiments, the harvested tissue has a thickness between about 260 μm and about 450 μm, and the further sliced tissue has an edge dimension between about 200 μm and about 1200 μm. In still other embodiments, the harvested tissue has a thickness between about 260 μm and about 450 μm, and the further sliced tissue has an edge dimension between about 500 μm and about 900 μm. In preferred embodiments, the harvested tissue has a thickness between about 260 μm and about 450 μm and the further sliced tissue has an edge dimension between about 750 μm and about 850 μm. 
   In accordance with a third aspect of the invention, processed dermal tissue includes sliced dermal tissue having a thickness between about 130 μm and about 840 μm and having an edge dimension between about 100 μm and about 5000 μm. 
   In some embodiments, the processed dermal tissue has a thickness between about 260 μm and about 450 μm and an edge dimension between about 200 μm and about 1200 μm. In other embodiments, the processed dermal tissue has a thickness between about 260 μm and about 450 μm and an edge dimension between about 500 μm and about 900 μm. In preferred embodiments, the processed dermal tissue has a thickness between about 260 μm and about 450 μm and an edge dimension between about 750 μm and about 850 μm. 
   The foregoing and other aspects of the invention will appear from the following description. In the description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration, and not limitation, a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference must therefore be made to the claims herein for interpreting the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view of a harvested dermal tissue processor constructed in accordance with the preferred embodiment of the invention; 
       FIG. 2  is an assembly view of the components of the harvested dermal tissue processor illustrated in  FIG. 1 ; 
       FIG. 3  is a top plan view of the harvested dermal tissue processor illustrated in  FIG. 1 ; 
       FIG. 4  is a bottom plan view of the harvested dermal tissue processor illustrated in  FIG. 1 ; 
       FIG. 5  is a sectional side elevation view of the harvested dermal tissue processor taken along line  5 - 5  of  FIG. 3 ; 
       FIG. 6  is a side elevation view of a cutting assembly forming part of the harvested dermal tissue processor illustrated in  FIG. 1 ; 
       FIG. 7  is a perspective view of the harvested dermal tissue processor illustrated in  FIG. 1  having a portion cut away; 
       FIG. 8  is a sectional side elevation view of the harvested dermal tissue processor illustrated in  FIG. 1  during a forward cutting operation; 
       FIG. 9  is a schematic illustration of the harvested tissue after a first forward cutting operation; 
       FIG. 10  is a sectional side elevation view of the harvested dermal tissue processor illustrated in  FIG. 1  during a backward cutting operation; 
       FIG. 11  is a schematic illustration of the harvested tissue after two cutting operations; 
       FIG. 12  is a perspective view of the harvested dermal tissue processor similar to the processor illustrated in  FIG. 1  but having hinged tissue separators in accordance with an alternate embodiment; 
       FIG. 13  is a perspective view of the harvested dermal tissue processor similar to the processor illustrated in  FIG. 1 , but including a slidable upper tissue separator in a stand-by position in accordance with an alternate embodiment; 
       FIG. 14  is a perspective view of the harvested dermal tissue processor similar to  FIG. 13 , but with the tissue separator in an engaged position; 
       FIG. 15  is a perspective view of the harvested dermal tissue processor similar to the processor illustrated in  FIG. 1 , but including a slidable lower tissue separator in a stand-by position in accordance with an alternate embodiment; 
       FIG. 16  is a perspective view of the harvested dermal tissue processor similar to  FIG. 15 , but with the tissue separator in an engaged position; 
       FIG. 17  is a perspective view of the harvested dermal tissue processor similar to the processor illustrated in  FIG. 1 , but including a second handle in a stand-by position in accordance with an alternate embodiment; and 
       FIG. 18  is a perspective view of the harvested dermal tissue processor similar to  FIG. 17 , but with the second handle in an engaged position. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , a disposable, handheld device  20  for processing harvested dermal tissue includes a housing  21  presenting a substantially horizontally extending handle  22  and an interconnecting cutting head  24  extending forwardly from the handle. Handle  22  and cutting head  24  extend generally in the same plane, and are preferably formed from a plastic that is molded as an integral frame. Unless stated otherwise, device  20  can be formed from any suitable plastic, and is preferably injection or otherwise molded. 
   Handle  22  defines an upper end  26 , a lower end (not shown) opposite the upper end, and opposing sides  28 . Handle  22  defines a necked-down gripping portion  30  at a location proximal the interface with cutting head  24 . A pair of side cutouts  32  are formed in opposing sides  28 , and a third cutout  34  is formed in the upper end  26 . Cutouts  32  and  34  are substantially aligned, and ergonomically sized and shaped to be comfortably engaged by a user&#39;s thumb and other fingers. Advantageously, because gripping portion  30  is symmetrical, device  20  can be equally engaged by a user&#39;s left or right hand in one of several ergonomic positions. 
   Referring also to  FIG. 2 , cutting head  24  is defined at its periphery by a frame that includes a laterally extending rear wall  38  attached to handle  22 , and side walls  40  extending forwardly from opposite ends of rear wall  38 . A collection plate  42  is disposed between side walls  40  and extends forwardly from rear wall  38  a distance less than the total length of side walls  40 . It should be appreciated that plate  42  extends in a plane that is lower than the plane defined by the upper edges of rear and side walls  38  and  40 . Accordingly, a receptacle  44  is formed from plate  42  along with walls  38  and  40  that receives processed tissue, as will be described in more detail below. A laterally extending front wall  46  connects the outer ends of side walls  40 . A void  50  is thus defined at the front of the cutting head  24  by front wall  46 , side walls  40 , and collection plate  42 . 
   Referring also to  FIGS. 5 and 6 , a cutting assembly  60  is disposed within void  50  at a position upstream from collection plate  42  with respect to the direction of processed tissue particle travel during operation. Cutting assembly  60  is formed from a plurality of generally circular metal cutting blades  62  spaced apart by a plurality of washers  64  interposed between adjacent blades  62 . Each blade  62  converges at its periphery to a circular blade tip  63 . Tips  63  can be formed with a double bevel, single bevel, or serrated or jagged edge. Washers  64  have a diameter less than the diameter of cutting blades  62  such that blade tips  63  extend outwardly from adjacent washers  64 . 
   Cutting assembly  60  is rotatably supported by cutting head  24 . In particular, a pair of aligned apertures  54  extends through the side walls  40  and receives a cylindrical axle  56 . Axle  56  extends through the apertures  54 , and receives a hub  58  extending centrally through cutting assembly  60 . In accordance with the preferred embodiment, axle  56  is preferably rotatably fixed in apertures  54 , and each blade  62  and washer  64  rotate independently around the axle  56 . Alternatively still, blades  62  and washers  64  can be interlocked or otherwise fastened to each other such that each cutting blade  62  is rotatably fixed to all other cutting blades of cutting assembly  60 . In this embodiment, the interlocked or fastened blades  62  and washers  64  can collectively rotate about axle  56 , which is fixed within apertures  54 . Alternatively still, the interlocked or fastened blades  62  and  64  can be fixed with respect to rotation about axle  56 , and axle can be inserted into apertures  54  via traditional roller bearings (not shown) that enable axle  56  to rotate with respect to cutting head  22 . 
   Washers  64  can assume any size, and preferably define a thickness between 100 μm and 5000 μm. The distance between adjacent blade tips  63  is limited by the thickness of the corresponding blade  62  and washer  64 , and is preferably within the range of 100 μm and 5000 μm, preferably between 200 μm and 1200 μm, more preferably between 500 μm and 900 μm, and most preferably between 750 μm and 850 μm. 
   While the cutting assembly  60  has been described in accordance with the preferred embodiment, a skilled artisan will appreciate that washers  64  could be eliminated such that blades  62  are disposed immediately adjacent each other, and the blade tips are spaced apart a distance equal to the thickness of each blade  62 . It should be further appreciated that cutting assembly  30  could be formed from a single elongated annular member having a plurality of spaced apart blade tips formed in its outer surface. The present invention is not intended to be limited to any of these embodiments. 
   Cutting head  24  defines a wide V-shaped base  49  that includes the lower surface  51  of plate  42 , and the lower surfaces  53  of side walls  40  at a location forward of plate. Lower surface  51  of plate  42  extends forward from rear wall  38 , and slightly downwardly at an angle between 10 and 50 degrees with respect to the horizontal plane. Lower surface  53  is beveled at a location laterally aligned with void  50 , and connect with lower surface  51 . Lower surface  53  preferably defines an angle in the range of 10 and 50 degrees with respect to the horizontal plane, and preferably 30 degrees. Accordingly, device  20  can be tilted forwards to engage cutting assembly  60  with the harvested tissue that is to be processed. 
   Referring also to  FIG. 7 , an upper and a lower tissue separator  66  and  68 , respectively, are fastened to cutting head  24  and engage cutting assembly  60  to remove tissue that may be disposed between adjacent blades  62  during cutting operations. Separators  66  and  68  are preferably formed from a metal, but could alternatively be formed from a plastic, ceramic, or other suitable material as appreciated by a skilled artisan. 
   Upper separator  66  is a comb-like structure that defines a laterally extending base  70  and a plurality of tines  72  extending forwardly from base  70 . Tines  72  define a thickness that is preferably slightly less than the thickness between adjacent blades  62 . Base  70  is mounted to the upper surface of collection plate  42  at a location such that adjacent tines  72  extend forwardly and interdigitate with corresponding adjacent blade tips  63  in a one-to-one relationship, as illustrated in  FIG. 3 . Tines  72  define distal ends  74  that ride along the outer surface of corresponding washers  64 , preferably between the 12:00 and 2:00 position, and more preferably at approximately the 12:00 position. It should be appreciated that the present invention is not to be construed as limited to the position of tines  72  with respect to washers  64 . Furthermore, if cutting assembly  60  does not include washers  64 , tines would extend between blade tips  63  to a location where sliced particles would tend to accumulate. 
   A mounting flange  76  extends forwardly from lower surface  51  of plate  42 , and slightly upwardly at an angle such that the lower surface of flange  76  extends along a plane that is tangential with respect to the outer periphery of washers  64 . Flange  76  is preferably coplanar with lower surface  53 . Lower separator  68  is a comb-like structure that defines a laterally extending base  78  and a plurality of tines  80  extending forwardly from base  78 . Tines  80  define a thickness that is preferably slightly less than the thickness between adjacent blades  62 . Base  78  is mounted to the lower surface of flange  76  such that adjacent tines  80  extend forwardly and interdigitate with corresponding adjacent blades  62  in a one-to-one relationship, as illustrated in  FIG. 4 . Tines  80  define distal ends  81  that ride along the outer surface of corresponding washers  64 , preferably at a position between 6:00 and 7:00. It should be appreciated that the present invention is not to be construed as limited to the position of tines  80  with respect to washers  64 . Furthermore, if cutting assembly  60  does not include washers  64 , tines  80  would extend between blade tips  63  to a location where sliced particles would tend to accumulate. 
   In accordance with an alternative embodiment, either or both separators  66  and  68  can be actuated between a stand-by position, whereby tines  72  and  80  are removed from the interstices between adjacent blades  62 , and an engaged position whereby tines  72  and  80  interdigitate with blades  62  as described above. For instance, referring to  FIG. 12 , bases  70  and  78  of separators  66  and  68 , respectively, can be attached to cutting head  24  via a hinge (not shown), thus allowing the collection mechanism to be raised to the stand-by position, and lowered to the engaged position. 
   Alternatively still, referring to  FIGS. 13 and 14 , a receptacle can be attached to the upper surface of cutting head  24 . Receptacle  82  includes a pair of opposing side walls  84  joined at their outer ends by a rear end wall  86 . A recessed collection plate  88  extends between side walls  84  and forwardly from end wall  86 , and receives processed tissue during operation of device  20 . Upper separator  66  is coupled to receptacle  82 , and rides along guide rails (not shown) that are carried by side walls  84 . The guide rails are angled such that separator  66  can be translated backwards and forward from the stand-by position illustrated in  FIG. 13  to the engaged position illustrated in  FIG. 14 . One or more detents can be formed in the guide rail and positioned to resist (though not prevent) translation of separator  66  away from both the stand-by and engaged positions. The detents enable a user to lock the separator  66  in the desired position during operation. 
   Referring to  FIGS. 15 and 16 , lower separator  68  can alternatively be mounted onto a ramp  90  that is attached to lower surface  51  of plate  42 . Ramp  90  presents a ramp surface  92  that is angled towards washers  64 . Separator  68  slidably rides along ramp surface  92  via guide rails (not shown) or the like, and can thus be translated from the stand-by position illustrated in  FIG. 15  to the engaged position illustrated in  FIG. 16 . One or more detents can be formed in the guide rail and positioned to resist (though not prevent) translation of separator  68  away from both the stand-by and engaged positions. The detents enable a user to lock the separator  68  in the desired position during operation. 
   Advantageously, because device  20  lacks complex electrical components, it can be manufactured inexpensively compared to conventional dermal tissue processing devices. 
   Operation of dermal tissue processing device  20  will now be described with reference to  FIGS. 8-11 . As will become apparent from the description below, device  20  is capable of performing a forward and backward cutting operations. 
   Referring initially to  FIG. 8 , a sheet of harvested dermal tissue  94  is disposed on a cutting surface  96 . Cutting surface  96  is preferably formed from a rubber, plastic, or other material suitable for supporting tissue  94  to be processed. It is desirable that surface  96  be sterile, sufficiently ductile and tacky to hold the tissue  94  in place and prevent slippage of the cutting blades  62 , and durable to resist being cut by the blades during operation. Separators  66  and  68  (if movable) are then brought into engagement with cutting assembly  60 . 
   With continuing reference to  FIG. 8 , device  20  is tilted up and forward at an angle approximately equal to the angle of beveled surface  53  such that both surfaces  51  and  53  are clear from interference with the cutting surface. Tilting the device  20  provides the user with increased leverage to apply downward force when performing cutting operations. 
   Device  20  is then lowered onto cutting surface  96  at a location immediately behind the tissue  94 . The user applies a sufficient amount of downward force to enable cutting blades  62  to penetrate through tissue  94 , and translates device  20  forward along the direction of Arrow A while maintaining engagement between blades  62  and cutting surface  96 . The forward cutting operation thus ensues, whereby blades  62  thus rotate counterclockwise as indicated by Arrow B as they cut through the tissue  94 . 
   Referring also to  FIG. 9 , the first forward cutting operation slices the tissue  94  into a plurality of adjacent fine strips  98  having a thickness T 1  substantially equal to distance between adjacent cutting blade tips  63 . As blades  62  rotate during the forward cutting operation, sliced tissue  94  tends to become immediately lodged within the interstices between adjacent blades. The lodged strips  98  rotate along with blades  62  towards lower separator  68 , and are brought into contact with the interdigitating tines  80 . The tissue  94  rides along the lower cam surfaces of tines  80 , becomes separated from cutting assembly  60 , and falls back onto cutting surface  96  as substantially parallel strips  98 . Lower separator  68  can be disengaged from cutting assembly  60  after the forward cutting operation, or blade can be rotated further counterclockwise, to force the distal ends of strips  98  onto the cutting surface  96 . Multiple passes may be made if, for instance, the width of the harvested tissue  94  is greater than the distance between outer cutting blades  62 . 
   Once the sheet of tissue  94  has been sliced and separated onto cutting surface  96 , a backward cutting operation can be performed by orienting device  20  in a second direction, such as 90 degrees. A 90 degree orientation is preferred such that the cutting direction extends substantially orthogonal with respect to the strips  98 . 
   In particular, device  20  is positioned in front of strips  94 , and lowered such that cutting assembly engages the front edge of the front-most strip. The user applies a sufficient amount of downward force to enable cutting blades  62  to penetrate through tissue  94 . The backward cutting operation ensues, whereby device  20  is translated backwards along the direction of Arrow C while maintaining engagement between blades  62  and tissue  94 . Blades  62  thus rotate clockwise as indicated by Arrow D. 
   Referring also to  FIG. 11 , if the backward cutting operation is performed immediately after the first forward cutting operation, the tissue  94  is sliced into fine particles  100  defined by two dimensions T 1  and T 2 , each of which being as small as the distance between adjacent blade tips  63 . Particles  100  in  FIG. 11  are illustrated schematically in a grid-like pattern to identify dimensions T 1  and T 2  of substantially square or rectangular particles. The particles  100 , of course, would separate and travel into receptacle  82  after the first backward cutting operation, and may not form a perfect grid on the cutting surface after two sequential forward cutting operations. In this regard, it should be appreciated that multiple cutting operations can be performed, in which case sliced particles can assume any geometric configuration, regular or irregular, such as rectangles, triangles, and trapezoids. Dimensions T 1  and T 2  are therefore intended to be broadly construed to individually define the length of at least one of the edges of a particle of sliced tissue using device  20 . 
   As blades  62  rotate clockwise during the backward cutting operation, particles  100  tend to become immediately lodged within the interstices between adjacent blades. The lodged particles  100  rotate along with blades  62  towards upper separator  66 , and are brought into contact with the interdigitating tines  72 . The lodged particles  100  accumulate on the upper surfaces of tines  72 , and are pushed backwards onto collection plate  42  by incoming particles  100  along the direction of Arrow E. The particles may then be easily inspected by the user using a forceps or the like to determine whether the desired particle sizes have been achieved. 
   Upper separator  68  can be disengaged from cutting assembly  60  after the backward cutting operation to force the remaining particles  100  onto collection plate  42 . Otherwise, if separator  68  is not movable, device  20  can be further translated along cutting surface  96  to ensure that all particles lodged in cutting assembly  60  engage the upper tines  72  and are removed. In rare instances, a tool can be inserted into the interstices between blades  62  and used to force the remaining particles  100  onto collection plate  42 . Multiple backwards passes can be made if, for instance, strips  98  are longer than the distance between outer cutting blades  62 . 
   After the first forward and backward cutting operations have been performed, particles  100  can define dimensions T 1  and T 2  within a range of about 100 μm and about 5000 μm, preferably between about 200 μm and about 1200 μm, more preferably between about 500 μm and about 900 μm, and most preferably between about 750 μm and about 850 μm depending on the distance between adjacent blade tips  63 . In addition, particles  100  can define a thickness of about 130 μm and about 840 μm, and preferably between about 260 μm and about 450 μm. As used herein, “about” means 10% above or below the stated range. 
   In some instances, the user may wish to perform more than one forward and backward cutting operation. In this instance, after the first forward cutting operation has been performed, additional cutting operations in either direction can be performed as desired. A backward cutting operation can then be performed to accumulate the further sliced particles in receptacle  82 . If, upon examination of the accumulated particles, the desired edge dimensions have not yet been achieved, the particles can be poured out of receptacle  82  onto cutting surface  96 , and one or more additional cutting operations can be performed. 
   It has been found that particles  100  having dimensions T 1  and T 2  between 100 μm and 5000 μm and having a thickness between 130 μm and 840 μm, can be prepared using device  20 . Transplanted particles as small as 750 μm, and having a thickness between 260 μm to 450 μm, achieve better results than larger particles, as they enable increased expansion ratios. Particles having a desired particle size can be transplanted into a wound. In the wound, particles  100  having these dimensions curl toward their epidermal side, resulting in a concave appearance that enhances proliferation on the particles&#39;  100  dermal (i.e., convex) side. To facilitate the curling, the particles are maintained in a moist or wet environment. 
   Advantageously, the present invention provides a dermal tissue processing device  20  that is portable, manually operated, and relatively inexpensive, thereby rendering the device  20  disposable after one use. The labor required to clean and sterilize conventional dermal tissue processors is thus avoided. It is further advantageous that the present device  20  can be positioned by the user in any desirable orientation relative to the tissue without having to adjust the position of the tissue. Device  20  thereby provides the user with enhanced cutting operation flexibility with respect to conventional devices. Furthermore, device  20  enables the operator to easily remove finely sliced particles from between adjacent blades  62 . 
   Referring now to  FIGS. 17 and 18 , an alternate embodiment of the present invention provides second handle  102  that can be connected to cutting head  24 . Handle  102  presents a second surface that can be engaged by the user to provide greater leverage when applying downward pressure during cutting operations. Second handle  102 , for instance, can define a gripping surface  104  connected to cutting head  24  via a pair of interconnecting legs  106 . Each leg  106  can define an aperture  108  extending therethrough and aligned with apertures  54 , such that axle  56  extends through both pairs of apertures  54  and  108 . Second handle  102  can thus be pivoted from a flat storage position as illustrated in  FIG. 17 , whereby gripping surface  104  rests against handle  22 , to an engaged position as illustrated in  FIG. 18 , whereby handle  102  extends substantially vertical. A flange  110  extends outwardly from front wall  46  and engages the forward surface of legs  106  when handle  102  is engaged to prevent over-rotation of the handle. 
   Alternatively, flange  110  can be configured to allow handle  102  to pivot to a position between the vertical position illustrated and a horizontal position on the opposite side of cutting head  24  with respect handle  22  to assist during forward cutting operations. Alternatively still, a second flange (not shown) can be provided that is selectively engaged and allows handle  102  to pivot to a position between the vertical and closed positions illustrated to assist during backward cutting operations. 
   The user can grip handle  22  with his or her dominant hand to guide the cutting direction, and engage second handle  102  with the other hand to apply additional downward force during the cutting operation. 
   The invention has been described in connection with what are presently considered to be the most practical and preferred embodiments. However, the present invention has been presented by way of illustration and is not intended to be limited to the disclosed embodiments. Accordingly, those skilled in the art will realize that the invention is intended to encompass all modifications and alternative arrangements included within the spirit and scope of the invention, as set forth by the appended claims.