Patent Publication Number: US-2006015128-A1

Title: Surgical devices and method for skin removal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      The present application claims the benefit of priority from co-pending provisional application 60/587,055, filed on Jul. 13, 2004, and the complete contents thereof is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to surgical cutting devices and scalpels. More particularly, the present invention relates to a cutting device for removing a strip of skin while minimizing damage to underlying vascular or nerve tissue.  
     BACKGROUND OF THE INVENTION  
      Certain surgical operations require the removal of a patch or strip of a top layer of skin (the epithelium). For example, breast reduction surgery, skin grafts, and certain cosmetic or reconstruction surgical procedures require epithelium removal.  
      Conventionally, scalpel or scissors are commonly used to remove the epithelium layer. The scalpel or scissors are typically held at a shallow angle, separating the skin from the underlying tissue by cutting. A problem with this conventional technique is that the depth of cut is difficult to control by the surgeon. Often when using a scalpel or scissors to remove epithelium, the blade has a tendency to dig into vascular tissue, causing unnecessary tissue or nerve damage. When removing epithelium, the depth of cut should be accurate and controllable to ensure adequate removal of the epithelium and simultaneously avoid damage to deeper vascular tissue or nerve endings.  
      Due to these difficulties, proper epithelium removal tends to be time-consuming and difficult for the surgeon and risky for the patient. Damage to vascular tissue increases the risk of complications.  
      It would be an advance in the art of surgery to provide a simple and effective device and method for epithelium removal causing minimal damage to underlying tissue, and providing a constant and easily controllable depth of cut. It would also be beneficial to have devices and new methods which make epithelium removal faster and easier for the surgeon. Such a device and method could be widely applicable in many surgical procedures.  
     SUMMARY OF THE INVENTION  
      An exemplary embodiment of the invention is to provide a cutting tool with a cutting edge designed to collect and cut epithelium tissue which has been lifted using tweezers or similar devices. Preferably the cutting area is in the shape of V, and the edges of the cutting area are sharpened so as to cut through the epithelium. The device allows removing strips of epithelium simply by applying a slight pushing pressure in the direction of the uplifted section of skin.  
      Another exemplary embodiment of the invention is to provide a kit which includes both a scoring tool and a cutting tool, wherein the scoring tool provides lines of cut epithelium tissue which can be lifted with tweezers or similar devices, and wherein the cutting tool can cut these lines of epithelium from the surface of the patient&#39;s skin simply by pushing a blade along the edge of the skin.  
      The present invention includes an epithelium cutting device for removing epithelium. The epithelium cutter has a handle for grasping, and a V-shaped blade attached to one end of the handle. The V-shaped blade has sharp inner edges that face away from the handle. Cutting action is provided by moving the handle and blade in a forward direction.  
      The handle may have a curved shape to accommodate a surgeon&#39;s fingers when the handle is placed against a relatively flat surface (e.g. a patients skin surface). The curved shape extends in a vertical direction. The V-shape blade is disposed in a substantially horizontal plane.  
      The handle may include a flat head portion, also disposed in the horizontal plane, parallel with the V-shaped blade.  
      The V-shaped blade preferably may have upwardly angled end portions. The end portions may each have an outside surface that is not sharp, thereby avoiding a digging action that might otherwise accompany a generally forward movement of the blade.  
      The V-shaped blade may comprise two separately fabricated (i.e. sharpened) blades that are butted together (unattached). Alternatively, the separate blades may be attached by welding or soldering, for example, or, the V-shaped blade can be molded, or punched from a single piece of metal, or otherwise formed such that the ends of the V-shape are integral with one another.  
      The V-shaped blade may be attached to the handle by set screws.  
      The present invention also includes a rake cutter for creating multiple, parallel cuts in the skin (these being akin to scoring lines). The parallel cuts prepare the skin for removal by the epithelium cutter. The rake cutter preferably comprises a handle for grasping and a plurality of spaced apart, parallel blades attached to one end of the handle. A sheath is disposed on the handle. The sheath can be moved along the handle to cover and uncover varying lengths of the parallel blades so that a depth of cut can be controlled. In addition, the sheath might selectively cover the entire length of the blade when the rake cutter is being stored or shipped.  
      In use, the uncovered length of the blades is preferably equal among the blades. Also, the sheath preferably has beveled surfaces. The sheath preferably can be locked in position, to fix the length of the exposed blades.  
      The present invention also encompasses a kit for epithelium removal which includes both the epithelium cutter and the rake cutter. The epithelium cutter preferably has a cutting width (i.e. the width of skin that can be removed by the epithelium cutter in one pass) that is substantially equal to (although being slightly larger (more preferred) or slightly smaller are also acceptable) the spacing between adjacent blades of the rake cutter. This allows the epithelium cutter to completely remove a strip of skin cut by the rake cutter. For example, the spacing between adjacent blades of the rake cutter can be 0-20% more or less than the cutting width of the epithelium cutter.  
      The present invention also includes a method for skin or epithelium removal. The method includes the steps of cutting multiple parallel cuts with the rake cutter, thereby defining at least one skin strip, and then lifting one end of a skin strip. Then, the V-shaped blade of the epithelium cutter is moved under the skin strip, between the skin and underlying vascular tissue. The epithelium cutter cuts away the skin strip from the vascular tissue, with minimal damage to the vascular tissue. However, due to the ease of use of the epithelium cutter, it is also possible to practice the invention simply by lifting a portion of the skin and cutting the epithelium with the epithelium cutter. 
    
    
     DESCRIPTION OF THE DRAWING FIGURES  
       FIG. 1  shows a perspective view of the epithelium cutter device of the present invention.  
       FIG. 2  shows a side view of the V-shaped blade of the epithelium cutter.  
       FIG. 3  shows a top view of the V-shaped blade.  
       FIGS. 4 and 5  show cross sectional views of two different embodiments of the V-shaped blade.  
       FIG. 6  shows a perspective view of the V-shaped blade.  
       FIG. 7  shows the epithelium cutter in operation beginning an incision.  
       FIG. 8  shows a side view of the epithelium cutter separating a strip of skin from underlying tissue (vascular tissue).  
       FIGS. 9A-9C  illustrate alternative embodiments of the V-shaped blade.  
       FIG. 10  shows a perspective view of a rake cutter for making multiple, parallel cuts.  
       FIG. 11  shows a top view of the present rake cutter.  
       FIG. 12  shows a side view of the rake cutter in operation.  
       FIG. 13  shows a top view of the epithelium cutter removing strips of skin between parallel cuts made by the rake cutter.  
       FIG. 14  shows a flow diagram describing the method of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION  
      The present invention provides devices and a method for removing epithelium in an easily controlled manner that minimizes damage to underlying tissue. The present epithelium cutter does not dig into vascular tissue, and reduces the time required for epithelium removal. The present epithelium cutter and method reduce surgery time, reduce surgeon fatigue, and improve patient safety and surgical outcome.  
      The present epithelium cutter has a handle and a V-shaped blade, with sharpened inner edges. The ends of the V-shaped blade are preferably angled upwardly, away from the skin when cutting. In operation, the skin is grasped with forceps or tweezers, and pulled upwardly, thereby creating a skin mound. The V-shaped blade is then positioned around the skin mound, and the skin mound is cut away by pushing the V-shaped blade into the skin. Continued pulling by the tweezers and cutting by the V-shaped blade removes a strip of skin, with a controlled depth of cut, and minimal damage to underlying vascular tissue and nerve endings.  
      Optionally, the skin can be pre-cut with a rake cutter according to the present invention. The rake cutter comprises 2, 3 or more parallel scalpel blades. When the skin is pre-cut with the rake, the V-shaped blade of the epithelium cutter does not need to cut through the skin; the epithelium cutter only separates the skin from the underlying tissue. Cuts made by the rake cutter improve the performance of the epithelium cutter.  
       FIG. 1  shows the epithelium cutter according to the present invention. The epithelium cutter has a handle  20  for grasping, and a V-shaped blade  24 . The handle  20  is preferably curved in an upward, vertical direction  21  as illustrated. The upward curve in the handle provides a space  28  (e.g., for a surgeons fingers) when the cutter is disposed on a flat surface  29  (e.g., the surface of a patient&#39;s skin). The V-shaped blade  24  is disposed in a horizontal plane, orthogonal to the vertical direction  21 . The handle  20  may include an optional head portion  22  that is flat and generally planar or parallel with the V-shaped blade  24 . The V-shaped blade  24  has sharp inner edges  26  for cutting. The V-shaped blade is attached to the handle so that the sharp edges  26  face away from the handle (i.e., such that the base of the V-shape is attached to the handle  20 ).  
      The handle  20  and head portion  22  can be injection molded and made of plastic or made of stainless steel, for example. The handle  20  and head portion  22  can be monolithic. The V-shaped blade  24  can be made of surgical steel, carbide, ceramics, or any other material used for surgical cutting devices.  
       FIG. 2  shows a close-up side view of the V-shaped blade  24 . Preferably, end portions  30  of the V-shaped blade  24  are angled upwardly (i.e., in the vertical direction  21 ). The angle  32  of the end portions  30  can be in the range of about 0-30 degrees, or 5-15 degrees, for example. The upward angle  32  tends to prevent the V-shaped blade  24  from digging or cutting into vascular tissue, and makes the cutting action more stable and controllable.  
      The V-shaped blade  24  may be bonded to the handle  20  by molding the handle  20  around the blade  24  (e.g., in an insert molding process). Alternatively, a set screw  34  or adhesive can be used to attach the V-shaped blade  24  to the handle  20 .  
       FIG. 3  shows a close-up top view of the V-shaped blade  24 . In one embodiment, the V-shaped blade  24  comprises two blades  24   a    24   b  butted together at boundary  36 . The two blades  24   a    24   b  may be welded or soldered together at the boundary  36 , or may be unbonded, and held in position by the handle  20 . Fabricating the V-shaped blade  24  from two separate blades  24   a    24   b  allows each blade  24   a    24   b  to be machined and sharpened individually, which is helpful for achieving sharp cutting edges close to the corner  33  of the V-shaped blade  24 .  
      The sharp inner edges  26  define an inner angle  38 . The inner angle  38  can be in the range of about 10-60 degrees, or, more typically, in the range of 20-30 degrees. The inner angle  38  can be selected to be wider or narrower depending on the type of tissue to be cut, the preference of the surgeon, or depending on other reasons. Typically, the inner angle  38  is fixed in an individual device, but it may be adjustable.  
      The V-shaped blade  24  has a cutting width  40 . The cutting width is the width of the sharp edges  26  as seen in the forward direction (in the plane of the page). The cutting width will typically be in the range of about ⅛-1 inch, or, more typically, in the range of about ¼-½ inch.  
      Typically, the sharp edges  26  terminate at point  31 , on the inside surface of the upwardly angled end portions  30 , as shown. In this case, the outside surfaces  42  of the end portions  30  are smooth and rounded, and are not cutting surfaces. Alternatively, portions of the outside surfaces  42  are sharpened.  
       FIG. 4  shows a cross sectional view of the V-shaped blade  24 , cut across line  43 . Preferably, the sharp edges  26  are on the bottom of the blade  24  as illustrated.  
       FIG. 5  shows a cross sectional view of an alternative embodiment in which the sharp edges  26  are disposed on a top surface of the V-shaped blade.  
      Alternatively, the sharp edges  26  can be located between the top and bottom surfaces of the blades  24 .  
       FIG. 6  shows a close-up perspective view of the V-shaped blade  24 .  
       FIG. 7  illustrates the epithelium cutter beginning an incision to remove skin  50 . to begin the incision, tweezer or forceps tips  52  are used to grasp the skin  50 . The tips are pulled upwardly  54  and lift the skin  50 , forming a mound. The V-shaped blade  24  is disposed around the skin mound, and pushed in a forward direction  56  so that the sharp edges  26  cut into the skin  50 .  
       FIG. 8  illustrates the operation of the epithelium cutter after the initial incision of  FIG. 7 . In  FIG. 8 , the tweezer tips  52  grasp a strip of removed skin  55  and pull upwardly and to the right so that the removed skin strip  55  is under tension. The V-shaped blade  24  is pushed to the left, so that the skin  50  is separated from underlying vascular tissue  58 . The present epithelium cutter can remove an arbitrarily long section of skin by the technique shown in  FIG. 8 . The upwardly angled end portions  30  help to prevent the V-shaped blade  24  from digging into the vascular tissue and cutting too deeply. The upwardly angled end portions  30  also help to stabilize the cutting action, so that the depth and location of the incision can be easily and accurately controlled by the surgeon. Further, the upwardly angled end portions  30  prevent the V-shaped blade  24  from digging into the vascular tissue.  
       FIGS. 9A-9C  illustrate alternative embodiments of the V-shaped blade. It should be understood from these figures that the “V” shape can encompass “U” shapes, or possibly even semicircular shapes. What is requires is that the epithelium is collected within a confined area and cut by the blade edges.  
       FIG. 9A : The sharp inner edges  26  have a convex shape. The end portions  30  do not have any sharp cutting edges.  
       FIG. 9B : The outside surfaces  42  are sharp and provide cutting action.  
       FIG. 9C : The sharp inner edges  26  have a concave shape.  
      The present invention may also include a rake cutter for use in combination with the present epithelium cutter (although it will be clear to those skilled in the art that the epithelium cutter might be used without the rake cutter). An exemplary rake cutter  59  is shown in  FIG. 10 . The rake cutter  59  comprises a handle  60 , a movable sheath  62 , and three parallel, spaced apart cutting blades  64   a    64   b    64   c . The blades  64   a    64   b    64   c  are attached to the end of the handle  60 . The sheath is movable along the handle  60  in direction  63 . The blades  64  can be covered or uncovered by the sheath  62  by moving the sheath along the handle.  
      Preferably, the sheath comprises beveled surfaces  66   a    66   b . The beveled surfaces can be placed against the skin during cutting so that the rake cutter is stabilized (e.g., so that the blades are maintained perpendicular to the skin during cutting). The rake cutter sheath  62  can have 3, 4 or more beveled surfaces  66 . Each beveled surface  66  can have a different angle. Preferably, the beveled surfaces of the sheath are aligned with the blades so that the blades are perpendicular to the skin surface when one of the beveled surfaces  66  is placed against the skin surface.  
       FIG. 11  shows a top view of the rake cutter. The blades  64  are preferably equally spaced as shown. The spacing  68  between the blades  64  can be in the range of about ⅛-1 inch, or, more typically, in the range of about ¼-½ inch. Preferably, in one embodiment of the invention, the spacing  68  between the blades  64  is equal to or slightly less than or slightly more than the cutting width  40  of the epithelium cutter (see  FIG. 3 ).  
       FIG. 12  shows a side view of the operation of the rake cutter. In operation, the position of the sheath  62  is adjusted for a desired cutting depth. The blades  64  are pushed into or against a skin surface  70  until a beveled surface is in contact with the skin. Each of the blades  64  will produce a cut having a constant and accurate depth  72 .  
       FIG. 13  shows a top view of the epithelium cutter illustrating how the epithelium cutter is used in combination with the rake cutter. The skin surface  70  has three parallel cuts  76   a    76   b    76   c  made by the rake cutter  59 . The three parallel cuts  76  define two adjacent skin strips  77   a    77   b  that remain attached to underlying vascular tissue. To remove the skin strip  77   a  the V-shaped blade  24  is moved under the skin strip  77   a  so that it is cut away from the vascular tissue. Tweezer tips  52  grasp the skin strip  77   a  and apply tension as it is cut. In order to remove skin from an entire area, many parallel, adjacent skin strips can be removed.  
       FIG. 14  shows a flow chart describing a method for skin removal according to the present invention. Preferably, the cutting width  40  of the V-shaped blade  24  is equal to or slightly greater (e.g. 5-25% greater) than the blade spacing  68  and distance between the cuts  76 . An adequate cutting width  40  ensures that the skin strip  77   a  is completely removed.  
      The cuts  76  made by the rake cutter make it unnecessary for the V-shaped blade  24  to cut through the skin (except at the start of cutting). The V-shaped blade  24  only needs to cut through underlying tissue, which makes the procedure faster and more controllable.  
      In the preferred commercial embodiment, the epithelium cutter will be a single use product, as will the rake blade cutter. The V-shaped blade of the epithelium cutter will be insert molded into a plastic handpiece, and it will preferably be packed and sold sterile. The rake blade cutter might also be packed together with the epithelium cutter, or, alternatively, it can be separately packed and sold separately.  
      It will be clear to one skilled in the art that the above embodiment may be altered in many ways without departing from the scope of the invention. Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents.