Patent Publication Number: US-2023146318-A1

Title: Multi-blade dermatome blade assembly and dermatome comprising the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to the field of dermatomes for surgically harvesting skin grafts. More particularly, the disclosure is directed to dermatome blade assemblies. 
     BACKGROUND 
     Dermatomes are devices used for cutting skin tissue to obtain skin grafts for transplantation. Typically, a dermatome has a vibrating or oscillating blade attached to a front end of a main body, which pushes the cutting blade in front of it like a reverse cheese slicer. The oscillation of the blade in a reciprocating side-to-side motion to create a slicing action can be powered either by an electric motor or compressed air. The dermatome currently dominant on the market is of such a design and made by Zimmer Inc., see e.g. EP 2 484 298 A1, US 2013/0018390 A1, U.S. Pat. No. 5,873,881 A1. One known disclosure of a blade assembly for conventional dermatomes is shown in EP 2 545 869 A1. 
     Recent studies have shown that improved results in skin grafting can be achieved by taking multiple thin skin grafts from the same donor site, so-called laminated grafts, instead of the conventional split-thickness of full-thickness skin grafts. According to this technique, the top skin layer (epidermis) is not cut off, but replaced to the original location at the donor site to close the wound after harvesting and allowed to heal again. This leads to substantially reduced healing problems and scarring will be significantly less, i.e. improved results at the donor site. 
     The second, and possibly third and fourth, layer(s) that is harvested will contain substantially more dermis components, which both provide better mechanical properties at the receiving area, but also contributes more stem cells, which have a higher long-term healing potential as they can divide more times and give rise to new cells than the more superficially located skin cells in the epidermis. This or these layer(s) is/are then used on the injured area. Possibly, the harvested skin layers also contain hair follicles and sebaceous gland cells, which improve the cosmetic appearance of the healed skin long-term and additionally obviates the need for daily rubbing or moisturising the transplanted skin surfaces, as is the case with conventional skin transplants. WO 2017/188888 A1 discloses a novel dermatome comprising multiple blades for simultaneously cutting separate skin grafts at different depths from a donor site. 
     One problem associated with combining this new technique of cutting multiple skin grafts with conventional dermatomes is that the drive mechanism to oscillate the blade is commonly located in the centre of the head in the form of a drive pin which extends through the blade assembly. As such, there is a risk that the drive pin interferes with or blocks passage of one or more of the cut skin grafts onto respective specially designed collection surfaces of the dermatome. 
     Hence, there is a need to further develop improved devices and implements for harvesting laminated skin transplants. 
     SUMMARY 
     An objective of at least some implementations of the present disclosure is to provide an improved device which enables simultaneous cutting of separate skin grafts at different depths from a donor site. This objective is achieved by providing a dermatome blade assembly according to a first aspect of the present disclosure, comprising: at least two blades, each including a cutting edge, a rear edge spaced from the cutting edge, and two side edges joining the cutting edge and the rear edge, wherein at least one of the blades comprises at least one throughgoing aperture; and a blade carrier including a main body extending in a transverse direction and means for connecting each of the at least two blades to the blade carrier; wherein the blade carrier comprises a recess arranged to receive a drive pin of a dermatome such that oscillating motion of the drive pin causes reciprocating motion of the dermatome blade assembly. 
     By means of the dermatome blade assembly, it is possible to connect two or more dermatome blades to the same blade carrier, directly or indirectly. The blade carrier in turn is arranged to be driven by the drive mechanism of a dermatome. Thereby, the reciprocating motion of the blade carrier is conveyed to the at least two blades which enables simultaneous cutting of skin grafts by each of the blades. 
     In one embodiment, blade connecting means extend from the main body in alignment with the at least one aperture on at least one of the blades, wherein the blade connecting means are arranged to be engaged with said at least one aperture for connecting said least one blade to the blade carrier. The blade connecting means engaged with the aperture provides a simple and reliable connection between the blade and the blade carrier which enables transmitting the transverse reciprocating motion from the blade carrier to the blade. 
     In one embodiment, the blade connecting means of the blade carrier are in alignment with apertures on each of the at least two blades, wherein the blade connecting means are arranged to be engaged with the respective apertures on each of the at least two blades for connecting each of the at least two blades to the blade carrier. This configuration allows for a direct connection of each of the blades to the blade carrier. 
     In one embodiment, the at least one blade connecting portion comprises at least one projection arranged to be received in the through-going aperture on each of the at least two blades. The projections allow for a simple, compact and reliable connection between the blades and the blade carrier when the dermatome blade assembly is mounted on a dermatome. 
     In one embodiment, at least one of the blades is integrally formed with or joined to the blade carrier by means of an adhesive, welding, crimping, moulding, soldering, brazing, or a combination thereof. In this way, a compact, preformed configuration for the connection between the blade and the blade carrier is achieved, requiring fewer assembly steps. 
     In one embodiment, the dermatome blade assembly further comprises at least one spacer element arranged to be mounted to the dermatome blade assembly in a position between each of the at least two blades to regulate a thickness of a skin graft cut by one of the at least two blades. The spacer element ensures that the thickness of the skin graft cut by lower blade(s) is limited to a desirable thickness instead of taking up all the available space between adjacent blades. Preferably, the dimensions of the spacer element may be varied in accordance with the desired thickness of the skin grafts to be cut. Preferably, the spacer element is adjustable. 
     In one embodiment, a first, upper blade is arranged offset from a second, lower blade in a cutting direction of the dermatome blade assembly. The offset configuration allows the blades to be brought into action in a staggered manner and enables the operator to maintain the position and inclination of the dermatome during the harvesting operation. 
     In one embodiment, the recess of the blade carrier is a slot or a through-going aperture arranged in a central position on the main body. The shape of the recess may be adapted to the design of the drive mechanism of the dermatome such that the drive pin is accommodated in the recess in an optimal manner for driving the dermatome blade assembly. 
     In one embodiment, each of the at least two blades are attached to a bottom side of the blade carrier. This configuration of the blades is adapted to dermatomes of the type having a dedicated space in the head of the main body for accommodating the blade carrier. Dermatomes manufactured by e.g. Nouvag AG are examples of such dermatomes. 
     In an alternative embodiment, at least a first, upper blade is attached to a top side of the blade carrier and at least a second, lower blade is attached to a bottom side of the blade carrier. This configuration offers a compact solution adapted to dermatomes of the type without a dedicated space in the head of the main body for accommodating the blade carrier. Dermatomes manufactured by e.g. Zimmer Surgical, Inc. are examples of such dermatomes. 
     In one embodiment, the dermatome blade assembly further comprises at least one intermediate plate, arranged between each of the at least two blades of the dermatome blade assembly and one bottom plate arranged below the lowermost blade of the dermatome blade assembly. The intermediate and bottom plates make up the surrounding structure of the dermatome blade assembly such that only the cutting edges of the two or more blades are exposed. The remaining parts of the blades are protected by the plates whilst allowing for reciprocating motion there within. 
     In one embodiment, a forward-facing lower surface of the at least one intermediate plate and the bottom plate comprises a central recess, wherein an extension of the recess in the transverse direction is shorter on the bottom plate than on the at least one intermediate plate. By providing a recess of smaller width in the bottom plate, the cutting width of the associated blade is limited such that this blade will not cut into the edges of the groove formed by the preceding blade. 
     In one embodiment, the recess in the at least one intermediate plate extends from a front end to a rear end of the at least one intermediate plate to form a cavity arranged to allow passage of a skin graft cut by a blade arranged below the at least one intermediate plate. This solution ensures that the cut skin graft by the lower blade(s) can be collected. 
     In a second aspect of the present disclosure, there is provided a dermatome comprising a dermatome blade assembly according to the first aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure is now described, by way of example, with reference to the accompanying drawings, in which: 
         FIGS.  1   a  and  1   b    show perspective views from below of a dermatome with a dermatome blade assembly according to one embodiment of the present disclosure mounted thereon; 
         FIG.  2    shows an exploded perspective view of a dermatome with a dermatome blade assembly according to one embodiment of the present disclosure; 
         FIG.  3    shows an exploded front view of a dermatome with a dermatome blade assembly according to one embodiment of the present disclosure; 
         FIG.  4   a    shows an exploded perspective view of a dermatome blade assembly according to one embodiment of the present disclosure; 
         FIG.  4   b    shows a perspective view of a dermatome blade assembly according to one embodiment of the present disclosure in an assembled state; 
         FIG.  5   a    shows an exploded perspective view of a dermatome blade assembly according to another embodiment of the present disclosure; and 
         FIG.  5   b    shows a perspective view of a dermatome blade assembly according to another embodiment of the present disclosure in an assembled state. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, a detailed description of a dermatome blade assembly according to the present disclosure is presented. In the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and do not in any way restrict the scope of the disclosure. 
     In  FIGS.  1   a    and  1   b,  there is shown an exemplary dermatome  10  comprising a dermatome blade assembly  100  according to one embodiment of the present disclosure mounted thereon. As mentioned above, the dermatome blade assembly  100  may be adapted to the type of dermatome with which it is intended to be used. The dermatome  10  shown in  FIGS.  1   a  and  1   b    should therefore not be construed as limiting in any way, but merely seen as one example, among others. 
     The dermatome  10  comprises a main body  12  with a head portion  14  connected to a handle  16 . The handle  16  may in turn be connected to an external power source (not shown) to oscillate the dermatome blade assembly  100  via a suitable drive mechanism. Alternatively, a motor may be accommodated within the head portion  14  for a standalone dermatome device. Further, the dermatome  10  comprises a thickness regulator in the form of an adjustable bracket  18  mounted on the head portion which may be adjusted by means of a wheel  20  on the side of the head portion. The bracket  18  regulates the thickness of the skin graft through variation of the space between the bracket  18  and a collection surface  22  on the front end of the head portion  14 . Typically, the thickness may be regulated in an interval of 0.05-1.0 mm. 
     Referring now to  FIGS.  2  and  3   , the dermatome blade assembly  100  according to one embodiment of the present disclosure is shown in an exploded view below the head portion  14  of the dermatome  10  to better illustrate the individual components. From top to bottom in  FIGS.  2  and  3   , there is shown a blade carrier  110 , a first blade  120 , an intermediate plate  130 , a spacer element  140 , a second blade  150  and a bottom plate  160 . Additionally, a pair of blade connecting means  115  according to one embodiment are shown, to connect the blades  120 ;  150  to the blade carrier  110 . 
     Referring now to  FIGS.  4   a  and  4   b   , blade carrier  110  has a main body  111  which extends in a transverse direction, perpendicular to the cutting direction of the dermatome. On opposite ends of the main body  111 , blade connecting means  115  extend downwardly from the main body  111 . In one embodiment, the blade connecting means comprises a cylindrical projection  115  which may be formed integrally with or separate from the main body  111 . Optionally, the cylindrical projection  115  may be tubular and a pin or screw (not shown) may be inserted through the tubular projection for connecting the blades  120 ;  150  to the blade carrier  110 . The first, upper blade  120  has been omitted in  FIGS.  4   a  and  4   b    for clarity, but should be thought of as being arranged between the blade carrier  110  and the intermediate plate  130  as shown in  FIGS.  2  and  3   . Other suitable cross-sectional shapes of the projections  115  are also encompassed in the present disclosure. Preferably, the blade carrier  110  is manufactured from a suitable plastic material with appropriate characteristics (lightweight, sufficiently rigid) to be used in conjunction with a dermatome. However, other medically acceptable materials such as metals or composites are also encompassed in the present disclosure. 
     Located centrally on the main body  111 , on the side facing away from the blade connecting means  115 , there is arranged a recess  112 . In one embodiment, the recess  112  is shaped like a slot or fork with two leg portions  113  extending from the main body  111  and arranged to receive a drive pin of the drive mechanism of the dermatome  10 . For instance, the drive pin may be arranged eccentrically in relation to a rotation axis such that the rotational motion of the drive pin is translated to a linear reciprocating motion of the blade carrier  110 . The main body  111  of the blade carrier  110  is shaped and dimensioned to be accommodated in a space in the head portion  14  of the dermatome  10 , as seen in  FIG.  1     a,  to allow for the reciprocating motion of the blade carrier  110 . 
     The blades  120 ;  150  shown in  FIGS.  2 ,  3  and  4     a - b  are conventional, rectangular metal blades as known in the art with a cutting front edge  122 ;  152 , a rear edge  124 ;  154  spaced from the cutting edge and two side edges  126 ,  128 ;  156 ,  158  joining the cutting edge  122 ;  152  and the rear edge  124 ;  154 . The first, upper blade  120  has been omitted in  FIGS.  3   a - 3   b    for improved clarity, but it is understood the dermatome blade assembly includes at least two blades. Other shapes of the blades  120 ;  150  are also foreseen within the scope of the present disclosure. 
     Each blade  120 ;  150  comprises at least one throughgoing aperture  121 ;  151 , which may be located adjacent each of the side edges  126 ,  128 ;  156 ,  158 , between the cutting edge  122 ;  152  and the rear edge  124 ;  154 , so as not to interfere with or block the central portion of the blade  120 ;  150 . However, at least on the first, upper blade  120 , other positions along the length of the blade  120  may also be foreseen within the scope of the present disclosure. In the present example, the first blade  120  has one aperture  121  near each side edge  126 ,  128  whereas the second blade  150  has two apertures  151  adjacent each side edge  156 ;  158 . The additional apertures on the second blade  150  allow for an offset or staggered configuration of the blades  120 ;  150 , as will be further explained below. The apertures  121 ;  151  may be circular to fit the cylindrical projections  115  of the blade carrier  110 . In one embodiment, at least one of the apertures  121 ;  151  has an oval shape to allow a certain play between the projection  115  and the aperture  121 ;  151 . Other suitable shapes of the apertures  121 ;  151  are also are also encompassed in the present disclosure. 
     Alternatively, the first, upper blade  120  may be attached or fastened to the blade carrier  110  using any suitable means, e.g. adhesive, welding, crimping, moulding, soldering, brazing etc. Such a configuration may be preformed to facilitate mounting of the dermatome blade assembly to the dermatome, reducing the number of steps. As an alternative, the blade  120  may be integrally formed with the blade carrier  110 . 
     When attaching or mounting the blades  120 ;  150  on the blade carrier  110 , the blade connecting means  115  are aligned with the apertures  121 ;  151  on each of the blades  120 ;  150  and brought into engagement therewith. To this end, there is provided an intermediate plate  130  to be positioned between the two blades  120 ;  150 , and a bottom plate  160  to be positioned beneath the second blade  150 . As will be understood, embodiments comprising three or more blades will similarly be provided with two or more intermediate plates, one positioned between adjacent blades of the dermatome blade assembly. The intermediate plate  130  and the bottom plate  160  are fastened to the head portion  14  of the dermatome  10 , e.g. by means of screws (not shown), to form a surrounding structure for the dermatome blade assembly  100 . 
     The upper and/or lower surfaces of the intermediate plate  130  and bottom plate  160  facing the respective blades are machined to form indentations in the surface to accommodate the blades  120 ;  150  and allow the reciprocating motion when the plates  130 ;  160  are fastened tightly together. The intermediate plate  130  and the bottom plate  160  also comprise lateral fully or partially cut-out portions  132 ;  162 , respectively, aligned with the projections  115  of the blade carrier  110  to allow the reciprocating motion of the blade carrier  110  in relation to the intermediate plate  130  and the bottom plate  160 . The forward-facing lower surface  134 ;  164  of the intermediate plate  130  and the bottom plate  160  is bevelled to provide an inclined working position of the dermatome  10  in order to minimise the area of contact with the skin and reduce friction. To this end, the length from the front to the rear end of the bottom plate  160  is adapted to the end point of the bevelled surface  134  on the intermediate plate  130  to create a smooth transition of the bevelled surfaces  134 ;  164 , as may be seen more clearly in  FIGS.  1   a    and  1   b.    
     As mentioned above, an offset configuration of the blades  120 ;  150  on the blade carrier  110  is used in conjunction with the bevelled surfaces  134 ;  164  of the intermediate plate  130  and bottom plate  160 . To this end, the projections  115  of the blade carrier  110  are aligned with the apertures  121  on the first, upper blade, which are located adjacent the rear edge  124 , and the front apertures  151  of the second, lower blade  150 , which are located adjacent the cutting edge  152 . 
     Additionally, the central portion of the forward-facing lower surface of each of the intermediate plate  130  and the bottom plate  160  comprises a recess  136 ;  166  which delimits the cutting width of the dermatome  10 . Different intermediate and bottom plates may have recesses  136 ;  166  of different widths to provide varying cutting widths by exchanging the plates. Preferably, the width of the recess  166  in the bottom plate  160  is smaller than the recess  136  in the intermediate plate  130 . This is to ensure that the cutting action of the second, lower blade  150  is limited to a smaller width than the groove cut by the first, upper blade  120 , i.e. the second blade will not cut into the edges of the groove. In this way, the second skin graft cut by the second blade  150  will be contained to the dermis layer of the skin to achieve a skin graft with the desired optimal properties as described above. 
     The recess  136 ;  166  may be inclined at an angle equal to or different from the bevelled forward-facing lower surfaces  134 ;  164 . On the bottom plate  160 , the central recess  166  is limited to the front portion of the lower surface, adjacent the bevelled surfaces  164 . However, the skin graft cut by the second, lower blade  150  needs to pass between the intermediate plate  130  and the bottom plate  160 . To this end, the central recess  136  in the lower surface of the intermediate plate  130  extends the entire length of the intermediate plate  130 , from the front to the rear, to form a cavity which allows passage of the cut skin graft there through. The height of this central recess  136  delimits the available space, and thus, the thickness of the skin graft cut by the second, lower blade  150 . 
     In order to regulate the thickness of the skin graft cut by the second, lower blade  150 , there is provided a spacer element  140  arranged to be positioned in the central recess  136  of the intermediate plate  130  when the dermatome blade assembly  100  is mounted on a dermatome  10 . The spacer element  140  extends over the full width of the central recess  136  and may be secured to the intermediate plate  130  by means of any suitable fasteners, such as e.g. screws. Different spacer elements  140  may have different shapes and/or dimensions to provide different thicknesses of the cut skin grafts by exchanging the spacer element  140 . The forward-facing surface of the spacer element  140  may be shaped to promote passage of the skin graft, e.g. bevelled or rounded. 
     In one embodiment, the spacer element  140  is adjustable to regulate the available height of the central recess  136 . This may be achieved by means of e.g. springs in the mounting between the spacer element  140  and the intermediate plate  130  and an actuating element. 
     Referring now to  FIG.  4   b   , the dermatome blade assembly  100  is shown in an assembled state, ready to be mounted on the head portion  14  of the dermatome  10 . In this view, it may be seen that the cut-out portions  132 ;  162  form a slot for receiving the projections  115  of the blade carrier  110  extending through the apertures  121 ;  151  in the blades  120 ;  150 , and allowing the transverse reciprocating motion of the blade carrier  110 . 
     Referring now to  FIGS.  5   a  and  5   b   , there is shown a second embodiment of a dermatome blade assembly  200  according to the present disclosure. Identical or similar features to the ones disclosed in conjunction with the dermatome blade assembly  100  according to the first embodiment, have corresponding reference signs beginning with the numeral “ 2 ” instead of “ 1 ”. Similar to the embodiment illustrated in  FIGS.  2 - 5   , the dermatome blade assembly  200  comprises a blade carrier  210 , a first blade  220 , an intermediate plate  230 , a spacer element  240 , a second blade  250  and a bottom plate  260 . The blade carrier  210  differs from the blade carrier  110  in that the blade connecting means  215  comprise ledges  216  on opposite ends of the main body  211  extending in a forward direction. This configuration allows for a more compact dermatome blade assembly  200 , suitable to be used with dermatomes which do not have a space for accommodating the blade carrier  210 . It is understood that the blade connecting means  215  may extend in a rearward direction as an alternative within the scope of the present disclosure. 
     On an upward-facing surface of the ledges  216 , there is provided a projection  217  which is arranged to be brought into engagement with the apertures  221  in the first, upper blade  220 . The upward-facing surface of the ledges  216  may be slightly indented in relation to an upper surface of the main body  211 , corresponding to the thickness of the blade  220 , such that the upper surface of the blade  220  is substantially flush with the main  211  body of the blade carrier  210  when resting on the ledges  216 . As may be seen in  FIGS.  5   a  and  5   b   , the first, upper blade  220  is mounted to the blade carrier  210  from above, whereas the second, lower blade  250  is mounted from below. To this end, blade connecting means in the form of projections (not shown) similar to the projections  217  are provided on a downward-facing side of the blade carrier  210 , which engage with the apertures  251  in the second, lower blade  250 . 
     Located centrally on the main body  211  there is arranged a recess  212 . In one embodiment, the recess  212  comprises a throughgoing aperture arranged to receive a drive pin of the drive mechanism of the dermatome  20 . For instance, the drive pin may be driven in a transverse reciprocating motion in relation to the dermatome, which is then translated to the blade carrier  210  via the throughgoing aperture  212 . 
     The blades  220 ;  250  shown in  FIGS.  5   a  and  5   b    are similar to the blades  120 ;  150  discussed in conjunction with  FIGS.  2 ,  4     a  and  4   b  above. Other shapes of the blades  220 ;  250  are also foreseen within the scope of the present disclosure. Each blade  220 ;  250  comprises at least one throughgoing aperture  221 ;  251  located adjacent each of the side edges  226 ,  228 ;  256 ,  258 , between the cutting edge  222 ;  252  and the rear edge  224 ;  254 . In the present example, the first blade  220  has one aperture  221  near each side edge  226 ,  228  whereas the second blade  250  has two apertures  251  adjacent each side edge  256 ;  258 . The additional apertures on the second blade  250  allow for an offset or staggered configuration of the blades  220 ;  250 , as will be further explained below. The apertures  221 ;  251  may be circular to fit the cylindrical projections  217  of the blade carrier  210 . In one embodiment, at least one of the apertures  221 ;  251  has an oval shape to allow a certain play between the projection  215  and the aperture  221 ;  251 . Other suitable shapes of the apertures  221 ;  251  are also encompassed in the present disclosure. 
     When attaching or mounting the blades  220 ;  250  on the blade carrier  210 , the blade connecting means  215  are aligned with the apertures  221 ;  251  on each of the blades  220 ;  250  and brought into engagement therewith. To this end, there is provided an intermediate plate  230  to be positioned between the two blades  220 ;  250 , and a bottom plate  260  to be positioned beneath the second blade  250 . As will be understood, embodiments comprising three or more blades will similarly be provided with two or more intermediate plates, one positioned between adjacent blades of the dermatome blade assembly. The intermediate plate  230  and the bottom plate  260  are fastened to the head portion of a suitable dermatome, e.g. by means of screws (not shown), to form a surrounding structure for the dermatome blade assembly  200 . 
     The upper and/or lower surfaces of the intermediate plate  230  and bottom plate  260  facing the respective blades are machined to form indentations in the surface to accommodate the blades  220 ;  250  and allow the reciprocating motion when the plates  230 ;  260  are fastened tightly together. The intermediate plate  230  also comprises a central fully cut-out portion  238 , arranged to receive the blade carrier  210  therein and to allow the reciprocating motion of the blade carrier  210  in relation to the intermediate plate  230 . As explained above, this embodiment is suitable to be used with dermatomes which do not have a space to accommodate the blade carrier  210 . 
     The bottom plate  260  comprises a transverse groove  262  arranged to receive the downward-facing projections of the blade carrier  210  to allow the reciprocating motion thereof. 
     The forward-facing lower surface  234 ;  264  of the intermediate plate  230  and the bottom plate  260  is bevelled to provide an inclined working position of the dermatome in order to minimise the area of contact with the skin and reduce friction. To this end, the length from the front to the rear end of the bottom plate  260  is adapted to the end point of the bevelled surface  234  on the intermediate plate  230  to create a smooth transition of the bevelled surfaces  234 ;  264 . 
     As mentioned above, an offset configuration of the blades  220 ;  250  on the blade carrier  210  is used in conjunction with the bevelled surfaces  234 ;  264  of the intermediate plate  230  and bottom plate  260 . To this end, the upper projections  217  of the blade carrier  210  are aligned with the apertures  221  on the first, upper blade, which are located adjacent the rear edge  224 , and the lower projections (not shown) engage with the front apertures  251  of the second, lower blade  250 , which are located adjacent the cutting edge  252 . 
     In one embodiment, it is foreseen that the blade carrier  210  is directly connected only to the first, upper blade  220  via the upper projections  217 . The first blade  220  is then in turn connected to the second blade  250  via separate connecting means through the apertures  221 ;  251 . In this case, the reciprocating motion of the drive pin is transmitted to the blade carrier  210 , which drives the first blade  220 , which in turn drives the second blade  250 . 
     Additionally, the central portion of the forward-facing lower surface of each of the intermediate plate  230  and the bottom plate  260  comprises a recess  236 ;  266  which delimits the cutting width of the dermatome  20 . Different intermediate and bottom plates may have recesses  236 ;  266  of different widths to provide varying cutting widths by exchanging the plates. Preferably, the width of the recess  266  in the bottom plate  260  is smaller than the recess  236  in the intermediate plate  230 . This is to ensure that the cutting action of the second, lower blade  250  is limited to a smaller width than the groove cut by the first, upper blade  220 , i.e. the second blade will not cut into the edges of the groove. In this way, the second skin graft cut by the second blade  250  will be contained to the dermis layer of the skin to achieve a skin graft with the desired optimal properties as described above. 
     The recess  236 ;  266  may be inclined at an angle equal to or different from the bevelled forward-facing lower surfaces  234 ;  264 . On the bottom plate  260 , the central recess  266  is limited to the front portion of the lower surface, adjacent the bevelled surfaces  264 . However, the skin graft cut by the second, lower blade  250  needs to pass between the intermediate plate  230  and the bottom plate  260 . To this end, the central recess  236  in the lower surface of the intermediate plate  230  extends the entire length of the intermediate plate  230 , from the front to the rear, to form a cavity which allows passage of the cut skin graft there through. The height of this central recess  236  delimits the available space, and thus, the thickness of the skin graft cut by the second, lower blade  250 . 
     In order to regulate the thickness of the skin graft cut by the second, lower blade  250 , there is provided a spacer element  240  arranged to be positioned in the central recess  236  of the intermediate plate  230  when the dermatome blade assembly  200  is mounted on a dermatome  20 . The spacer element  240  extends over the full width of the central recess  236  and may be secured to the intermediate plate  230  by means of any suitable fasteners, such as e.g. screws. Different spacer elements  240  may have different shapes and/or dimensions to provide different thicknesses of the cut skin grafts by exchanging the spacer element  240 . The forward-facing surface of the spacer element  240  may be shaped to promote passage of the skin graft, e.g. bevelled or rounded. 
     In one embodiment, the spacer element  240  is adjustable to regulate the available height of the central recess  236 . This may be achieved by means of e.g. springs in the mounting between the spacer element  240  and the intermediate plate  230  and an actuating element. 
     Referring now to  FIG.  5   b   , the dermatome blade assembly  200  is shown in an assembled state, ready to be mounted on the head portion of a suitable dermatome. 
     Preferred embodiments of a dermatome blade assembly have been disclosed above. However, a person skilled in the art realises that this can be varied within the scope of the appended claims without departing from the idea. 
     All the described alternative embodiments above or parts of an embodiment can be freely combined or employed separately from each other without departing from the idea as long as the combination is not contradictory. 
     Certain embodiments or components or features of components have been noted herein as being “preferred” and some options as being “preferable” or the like and such indications are to be understood as relating to a preference of the applicant at the time this application was filed. Such embodiments, components or features noted as being “preferred” or “preferable” or the like are optional and are not required for implementation of the innovations disclosed herein unless otherwise indicated as being required, or specifically included within the claims that follow.