Abstract:
A dermatome including a battery unit, a handle, and a head portion. The head portion includes guards capable of being adjusted to control the width and the depth of the cut without an interruption in the medical procedure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/766,513, entitled “Dermatome with Adjustable Width and Depth Guards” and filed on Feb. 19, 2013. The complete disclosure of said provisional patent application is hereby incorporated by reference. 
    
    
     STATEMENT REGARDING FEDERALLY FUNDED SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a device for harvesting skin and excising burns, and in particular to a dermatome with adjustable guards to control the width and depth of the cut without interruption of the medical procedure. 
     2. Brief Description of the Related Art 
     A dermatome is a medical instrument that has used since the 1940&#39;s when it was developed for a split thickness skin graft. A skin graft is a patch of healthy skin that is harvested from one area of the body or donor site to cover a damaged or skinless area of the body. Surgeons recently have been using a dermatome for excising burn wounds, especially over relatively flat surfaces such as the back, chest, and lower extremities. 
     Depending on the area of the body, the extent of the damaged tissue, and other factors, the width and depth of the skin being harvested or burned tissue being excised will vary. To allow for this variance, the prior art dermatomes comprise attachable guards that control the portion of the blade that is exposed to the skin. The greater the portion of the blade exposed laterally, the greater the width of the cut. The greater the height of blade exposed from the front edge of the device, the greater the depth of the cut. To adjust the width of the cut during the medical procedure, however, the guard has to be mechanically changed. This changing process consists of stopping the medical procedure, disconnecting the dermatome, detaching the guard (e.g. unscrewing the guard from the dermatome), attaching the new guard (e.g. screwing the guard to the dermatome), and resuming the medical procedure. This process is very time consuming, which wastes valuable operating room time. 
     In addition, prior art dermatomes are not designed for both harvesting skin and excising burned tissue. Thus, in order to excise burns, several runs at the maximum blade depth of the dermatome is often required. This process can also be very time consuming and thus costly to the patient. 
     Many of the prior art dermatomes are air-powered, thus relying on an air connection, which requires a long, heavy tubing that interferes with the surgeon and can clutter the operative field. Because of the pressure exerted on the dermatome, the prior art dermatomes are generally made of steel or other strong materials. As a result, the dermatomes are heavy and often difficult to maneuver. It has also been observed that the blade of the prior art dermatomes often becomes dull very quickly. On average, after four harvests of skin, or two excisions of burns, the blade must be changed. The blade changing process involves disconnecting the dermatome, detaching the guard, changing the blade, reattaching the guard, and then reconnecting the dermatome. 
     Moreover, prior art dermatomes designed to excise burned tissue utilize blades that have been in practice for over 60 years. The blades are known for frequently digging into the skin during excision creating lacerations that must be repaired. In addition, they produce ragged edges that can be cosmetically unsightly. 
     It would therefore be desirable to develop a dermatome with adjustable guards to control both the width and the depth of the cut without interruption of the skin harvesting or burn excision procedure. 
     It would also be desirable to develop a dermatome that is capable of excising damaged tissue with a single pass. 
     It would also be desirable to develop a dermatome that is lighter in weight, battery-powered, and has a blade that will allow multiple harvests and excisions without necessitating a blade change. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is directed to a dermatome comprising a battery, a handle, and a head portion, wherein said head portion comprises guards capable of being adjusted to control the width and the depth of the cut without an interruption in the medical procedure. 
     These and other features, objects and advantages of the present invention will become better understood from consideration of the following detailed description of the preferred embodiments, in conjunction with the drawings as described immediately below. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1A  is a top plan view of the dermatome of the present invention. 
         FIG. 1B  is a right side elevational view of the dermatome of the present invention. 
         FIG. 2  is a front elevational view of the dermatome of the present invention. 
         FIG. 3  is a bottom left perspective view of the head unit of the dermatome of the present invention. 
         FIG. 4  is a top rear perspective view of the head unit of the dermatome of the present invention. 
         FIG. 5  is a sectional perspective view from the top left of the dermatome of the present invention. 
         FIG. 6  is a back view of the dermatome of the present invention. 
         FIG. 7  is a top plan cut-away view of the dermatome of the present invention with internal features shown by broken lines. 
         FIG. 8  is a left top perspective view of the dermatome of the present invention. 
         FIG. 9  is a perspective sectional view from the top left of the dermatome of the present invention. 
         FIG. 10  is a perspective view from the top left of the dermatome of the present invention. 
         FIG. 11  is a bottom left perspective view of the head unit of the dermatome of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIGS. 1-11 , the preferred embodiments of the present invention may be described. The dermatome  10  is comprised of a handle  12 , a battery unit  14 , and a head unit  16 . The handle  12  is attached to the battery unit  14  at one end and the head unit  16  at the other end. As shown in  FIG. 1A  from a top view, the head unit  16  is substantially an irregular hexagon shape. The back end  18  of the head unit  16 , which is the end attached to the handle  12 , is parallel to the front end  20  of the head unit  16 , which is at the opposite end of the head unit  16 . The back end  18  of the head unit  20  is shorter in length than the front end  20  of the head unit  16 . As shown in  FIG. 1B , the head unit  16  slopes from the back end  18  of the head unit  16  to the front end  20  of the head unit  16 . 
     As shown in  FIG. 2  and  FIG. 11 , the front end  20  of head unit  16  comprises a blade  22 , an axle  24 , and two blade guard units  26 . The axle  24  extends across the length of the front end  20  of the head unit  16 , thus between the left side wall  28  and right side wall  28  of the head unit  16 . The axle  24  is preferably cylindrical in shape. Two blade guard units  26  are received by the axle  24 . Each blade guard unit  26  is comprised of a top section  30 , middle section  32 , and bottom section  34 . The middle section  32  is substantially vertical and comprises a circular hole in the middle where the blade guard unit  26  is received by the axle  24 . Attached to the middle section  32  at one end is top section  30 , which is arc-shaped. Attached to the middle section  32  at the opposite end is bottom section  34 . The bottom section  34  extends perpendicularly to the middle section  32 . The bottom sections  34  of the two blade guard units  26  extend away from each other towards the left and right ends  28  of the head unit  16 . The blade  22  abuts the bottom sections  34  of the blade guard units  26 . Thus, the blade edge is only exposed on the portion of the blade between the two blade guard units  26 . Because bottom sections  34  of the blade guard units  26  may contact the skin of the patient when the distance between the blade guard units  26  is maximized for wide cuts, in an alternative embodiment, bottom sections  34  of blade guard units  26  may be curved at their ends to avoid contact with the skin. 
     As shown in  FIG. 8 , the arc-shaped top section  30  allows the medical professional operating the dermatome  10  to easily grab the blade guard unit  26  and move it left or right along the axle  24 . In this regard, the width of the cut can be controlled in real time. For example, as the physician is moving the dermatome across the surface of the patient&#39;s skin, the physician can manually move the blade guard units to increase or decrease the width of the cut of skin or skin tissue being removed from the patient. In addition to moving side-to-side along the axle  24 , in one embodiment, the blade guard units may be rotated on the axle  24  from the front end  20  of the head unit  16  to the back end  18 , and vice versa. While the blade guard units  26  can be manually moved along the axle  24 , in an alternative embodiment, the blade guard units  26  can be moved relative to one another by electronic means. 
     As shown in  FIG. 11 , blade  22  is secured between a blade plate  42  and the bottom surface of head unit  16 . The blade plate  42  and the bottom surface of the head unit  16  are preferably attached via two screws. In the preferred embodiments, however, the blade  22  is not permanently attached to either the head unit  16  or the blade plate  42 . The blade  22  has a sharp blade edge facing outward from the front end  20  of the head unit  16  of the dermatome  10 , which generally defines a plane P that is generally parallel to longitudinal axis L as shown in  FIG. 8 . The axis L is generally defined by the dermatome  10  such that the handle  12  also generally extends along axis L. 
     As shown in  FIG. 7 , a blade driver  44  is in communication with the blade  22 , which allows the blade  22  to oscillate and cut the skin tissue when the sharp blade edge makes contact with the skin tissue. The blade driver is preferably a rotational motor and is of the type well-known to those skilled in the art. The blade  22  can preferably move laterally approximately five millimeters. 
     The dermatome  10  also comprises a depth adjuster system. The depth adjuster allows the surgeon to adjust the depth of the blade  22  that is exposed to the patient&#39;s skin and thus control the depth of the skin harvested or tissue excised during the surgery. As shown in  FIG. 7 , the depth adjuster system is comprised of two stepper motor actuators  36  in communication with means for activating the actuators, preferably a button panel  48 . Two actuators are preferable for safety and stability of the dermatome  10 . By pushing button  50 , the actuator  36  extends the blade  22  in increments (e.g. 2/1000 inch) towards the front end  20  of the head unit  16 . By protracting the blade, the portion of the blade  22  that is exposed is increased. In one embodiment, in addition to moving the blade forward, the blade is also tilted downwardly. Button  50  can subsequently be pushed to further adjust the blade exposure as necessary for the particular medical procedure. In contrast, by pushing button  52 , the blade  22  is retracted away from the front end  20  of the head unit  16  and the exposed blade is decreased by an increment, such as 2/1000 inch. Button  52  can also be pushed again to adjust the blade exposure as necessary for the particular medical procedure. In an alternative embodiment, the blade  22  can be controlled by buttons  50 ,  52  allowing the user of the dermatome to also change the blade angle on the fly (i.e. in real time). The depth adjuster system and blade  22  are configured to cut as small as 30/1,000 inch of skin tissue. 
     In an alternative embodiment, the depth adjuster system can be controlled electronically through use of one or more lasers and one or more sensors in the dermatome  10 . As the dermatome  10  contacts the skin of the patient, the laser (not shown) emits light through the skin. The reflected light is then received by a sensor (not shown). The amount of light received by the sensor will differ depending on the depth of the damaged tissue. The laser and sensor are integrated into a feedback system in which the blade guard units  26  and depth adjuster system can be electronically altered to ensure that only damaged tissue is cut. As an alternative to a laser, a low powered ultrasound (not shown) could also be used in this feedback system. 
     The blade  22  comprises a low friction coating, preferably Teflon® coating or carbon-like diamond coating which allows multiple harvests and/or excisions without the need to lubricate or change the blade. The battery  14  alleviates the need for heavy tubing and an air connection, thus making the dermatome  10  lighter and easier to operate. The dermatome is preferably made of aluminum, magnesium alloys, or other composite materials. These materials are significantly lighter than steel. 
     As shown in  FIGS. 3-4 , the head unit  16  and the handle  12  are attached via complementary connectors found on the back end  18  of head unit  16  and the front end  38  of the handle  12 . By holding the lever  40  on the back end  20  of the head unit  16 , power is supplied from the battery  14  to allow movement of the blade  22 . The lever  40  is in communication with the other portions of the dermatome  10  via a circuit board or processor of the type that is well-known to those skilled in the art. In one embodiment, the dermatome  10  is also comprised of a safety button  54  located on the button panel  48 . In this embodiment, the lever  40  must be held and the safety button  54  pushed before power is supplied from the battery  14 . To stop the motion of the blade  22 , the lever  40  can be released.  FIGS. 5, 7 and 9  show the inner mechanical workings of the power system of the dermatome  10 , including the battery  14  and the power switch  46 , which is in communication with the lever  40 . The battery  14  is preferably a standard non-sterile ortho pack which is well-known to those skilled in the art. 
     The present invention has been described with reference to certain preferred and alternative embodiments that are intended to be exemplary only and not limiting to the full scope of the present invention.