Abstract:
Disclosed herein is a surgical instrument having a cylindrical tube affixed thereto. The axis of the cylindrical tube is aligned with a central axis of the surgical instrument so it can be advanced along a guidewire.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Application No. 61/601,701, filed Feb. 22, 2012, the entire content of which is incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention is directed to a surgical instrument having a cylindrical tube for accommodating a guidewire therein. 
     BACKGROUND OF THE INVENTION 
     Surgical instruments, such as scalpels, are used to make an incision in the skin, enabling insertion of devices whose purpose is to deliver various substances to the body. In order to minimize the size of the incision, a guidewire is inserted into the body cavity and instruments can be reliably advanced over the guidewire and into the body cavity for proper placement. This method is known as the “Seldinger Technique.” In many circumstances, the guidewire incision needs to be widened in order to accommodate larger medical devices such as a trocar or catheter. The enlargement is typically done by hand which may lead to an imprecise or larger than needed cut. Therefore, a need clearly exists for a surgical instrument capable of using the guidewire to aid a surgical device, such as a scalpel, in making a more precise incision 
     SUMMARY OF THE INVENTION 
     The present invention provides a surgical instrument with a cylindrical tube affixed thereto. Preferably, the cylindrical tube is affixed to a top edge of the surgical instrument. However, the cylindrical tube may be affixed to any side (e.g., side or bottom) depending upon the intended use of the surgical instrument. 
     The cylindrical tube is affixed close to the tip of the surgical instrument to minimize the distance between the tip of the surgical instrument and the edge and the guidewire. This allows a user, for example, to minimize the size of an incision and to eliminate the potential for inadvertent skin nicks. In some embodiments, the surgical instrument can also be housed in a sheath. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of the surgical instrument having a cylindrical tube attached thereto. 
         FIG. 2  is a view of the surgical instrument of  FIG. 1  with a guidewire inserted through the cylindrical tube. 
         FIGS. 3-5  are views of an alternate embodiment of the surgical instrument encased in a sheath. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best mode or modes of the invention presently contemplated. Such description is not intended to be understood in a limiting sense, but to be an example of the invention presented solely for illustration thereof, and by reference to which in connection with the following description and the accompanying drawings one skilled in the art may be advised of the advantages and construction of the invention. In the various views of the drawings, like reference characters designate like or similar parts. 
     With reference to  FIG. 1 , depicted in surgical instrument  100  having proximal end  102  and distal end  104 . Distal end  104  has cylindrical tube  106  affixed to the edge of the surgical instrument  100  for accommodating a guidewire. As shown, cylindrical tube  106  is affixed to the top edge of the surgical instrument  100 . However, cylindrical tube  106  may be affixed to any side (e.g., sides or bottom) depending upon the intended use of surgical instrument  100 . Proximal end  102  preferably comprises a handle to allow a user to operate surgical device  100 . 
     In a preferred embodiment, surgical instrument  100  is a scalpel having cutting edge  108  for cutting a skin surface. Cutting edge  108  may comprise a cap or cover in order to protect a user and prevent cutting edge  108  from dulling. Cylindrical tube  106  is affixed close to tip  110  of surgical instrument  100  to minimize the distance between tip  110  and the edge and a guidewire inserted through cylindrical tube  106 . 
     To use surgical instrument  100 , guidewire  112  is threaded through cylindrical tube  106  as depicted in  FIG. 2 . Surgical instrument  100  can then be advanced over guidewire  112  to a skin surface (not shown). An incision can then be made using cutting edge  108 . The incision is precise because cylindrical tube  106  limits the range of movement of surgical instrument  100 , thereby avoiding any inadvertent skin nicks to the skin surface. Additionally, the cylindrical tube  106  allows for precise movement of surgical instrument  100 , thereby eliminating residual skin tags after incision that may prevent smooth advancement of catheters or devices over the guidewire  112 . 
     An alternate embodiment of surgical instrument  100  is depicted in  FIGS. 3-5 . As shown, surgical instrument  100  can be encased in sheath  200 . Sheath  200  has a first channel  202  for accommodating the connection between button  204  and surgical instrument  100 . Button  204  is used to move surgical instrument  100  from a closed position ( FIG. 4 ) to an open position ( FIG. 3 ). In some embodiments, the surgical instrument is maintained in the open and/or closed position by a locking mechanism, similar to that of a utility knife. Sheath  200  further comprises a second channel  206  for accommodating cylindrical tube  106  when surgical instrument  100  is in a closed position. 
     Sheath  200  protects an operator from lacerations while threading guidewire  106  through cylindrical tube  106 . For example, during threading, surgical instrument  100  remains in a closed position ( FIG. 4 ). Surgical instrument  100  can then be advanced to an open position ( FIG. 3 ) when surgical instrument  100  is close to the desired incision location. 
     While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto.