Abstract:
A single tool penetrates a target vessel and cuts an incision of a known length in the vessel. The tool is easily held by the user in one hand and actuated with that single hand. The tool has features to allow for easy penetration of the target vessel as well as safety features integrated within the tool itself. User input features are located conveniently on the exterior of the tool.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to surgery, and more specifically to creating an accurate-length incision in the wall of a tubular structure such as a coronary blood vessel. 
     BACKGROUND 
     Anastomosis is a procedure where two separate tubular or hollow organs are surgically grafted together to form a flexible conduit. In a coronary artery bypass graft (CABG) procedure, one end of the graft vessel is usually attached to the aorta and the other to the coronary artery to bypass the blocked area and reroute blood flow to the heart. Prior to an anastomotic procedure between the coronary artery and the graft vessel, a surgeon usually creates an incision in the coronary artery before the graft vessel is attached. This incision is known as an arteriotomy. Currently, creating an arteriotomy requires the use of separate tools to penetrate the vessel and create the incision. The use of multiple tools to complete a simple task such as creating an arteriotomy can lengthen the amount of time a patient spends in the operating room. Accordingly, a need exists for a tool that is capable of performing both functions of puncturing the vessel and creating the incision within the same vessel. 
     SUMMARY 
     An integrated tool for preparing a target vessel such as the coronary artery prior to an anastomotic procedure includes features for puncturing the target vessel and creating an incision therein. 
     In one aspect of the invention, a needle with a sharpened endpoint is combined with a cutting member into a single tool having a housing structure. The cutting member is slidable relative to the needle. The needle and the cutting member are both held by the housing structure such that the needle is fixed at the distal end of the tool but the cutting member can travel linearly to create the incision. 
     In another aspect of the invention, the tip of the needle serves to penetrate the target vessel at the intended anastomosis site. The puncture serves as a first end of the incision to be created. 
     In another aspect of the invention, a slot in the needle guides the cutting member as it cuts through the vessel wall. The cutting member includes a nose to guide the cutting member through the vessel beginning at the point where the needle has penetrated the vessel. The translational motion of the cutting member creates an incision in the wall of the vessel as it moves through the slot in the needle. 
     In another aspect of the invention, the needle has a lumen that houses a tip protector. After the needle penetrates the wall of the vessel, the tip protector is extended past the tip of the needle to blunt the end of the needle. By protruding past the sharp tip of the needle, the tip protector protects the back wall of the vessel from accidental damage due to excessive advancement of the sharp tip of the needle following penetration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a tool for penetrating and creating an incision in a vessel in deployment position. 
         FIG. 1A  is a side cross-sectional view of the tool. 
         FIG. 2  is an enlarged perspective view of the distal portion of the tool with a tip protector retracted into a needle. 
         FIG. 3  is an enlarged perspective view of the distal portion of the tool with the tip protector extending past the tip of the needle. 
         FIG. 4  is a front view of the tool. 
         FIG. 5  is a perspective view of the tool with the needle fully inserted into the vessel. 
         FIG. 6  is a perspective view of the tool with a cutting member moved forward to create the incision. 
         FIG. 7  is a perspective view of the tool after the cutting member has been deployed. 
     
    
    
     DETAILED DESCRIPTION 
     A single-piece tool  10  is used to rapidly create an accurate, high-quality incision of a predefined length in a perfused or non-perfused vessel. 
     Referring to  FIG. 1 , a needle  16  is fixed to the distal end of a housing  14  of the tool  10 . The needle  16  is a substantially cylindrical tube, but may have a different cross-section if desired. A single slot  25  along one side of the needle  16  extends from outside the needle into the lumen of the needle  16 . The slot  25  extends substantially parallel to the axis of the needle  16 . Alternatively, the slot  25  extends in a direction not substantially parallel to the axis of the needle  16  over at least a portion of its length. The tip  24  of the needle  16  is angled such that the slot  25  resides on the shortest side of the needle  16 , with the longest side of the needle  16  being directly opposite the slot  25 . Alternatively, the slot  25  has a different placement with regards to the orientation of the needle  16 . Alternatively, there is more than one slot  25  through the needle  16 . In addition, the tip  24  of the needle  16  may be shaped differently. 
     Referring to  FIG. 1A , the proximal end of the housing structure  14  terminates in a handle  13 . The handle  13  is angled at approximately 120 degrees with respect to the remaining portion of the tool  10  to enable the user to easily reach the target vessel. The handle  13  may be angled or configured differently, or may be omitted altogether. 
     A first user input feature such as a button  22  controls the actuation of a tip protector  18 . This is done via a cam  40 . The cam  40  has a feature  33  at its proximal end that is slightly smaller in diameter than the inner diameter of a spring  34 . One end of the spring  34  is connected to a surface  36  of a cavity  38  within the housing  14 . The cam  40  itself is configured to translate within that cavity  38 . The other end of the spring  34  holds the feature  33 . The coils of the spring  34  act against a shoulder  35  of the cam  40 . The spring  34  is a compression spring configured to bias the cam  40  toward the distal end of the housing  14 . 
     Two flat, beveled surfaces  44  and  46  are substantially parallel to each other and roughly 45 degrees from the plane A as defined in  FIG. 1 . Plane A is arbitrarily defined as “horizontal” and the direction perpendicular to the plane A is arbitrarily defined as “vertical” in order to describe the structure and operation of the tool  10  clearly. These conventions are solely utilized to clarify this description, and do not limit the orientation of the tool  10  in use. The surfaces  44  and  46  instead may be oriented at a different angle from the one shown here. The first surface  44  is located on the underside of the button  22 . The second surface  46  is located on the front portion of the cam  40 . Prior to actuating the button  22 , the two surfaces  44  and  46  may or may not be in contact with each other. As the button  22  is depressed, the surface  44  contacts and slides against the surface  46  on the distal portion of the cam  40 . This sliding motion forces the cam  40  proximally, because the motion of the button  22  is substantially constrained to the vertical direction. When the button  22  is pushed by the user, the movement of the button  22  in the substantially vertical direction of arrow A causes the cam  40  to move in the substantially perpendicular horizontal direction indicated by arrow B. As the cam  42  translates proximally, it compresses the spring  34  that is attached to the surface  36  at the end of the cavity  38  within the tool housing  14 . The two surfaces  44  and  46  continue to slide against each other until the button  22  is completely depressed and the overlapping areas of the two surfaces  44  and  46  are at a maximum. 
     The cam  40  holds one end of a wire  42 . The other end of the wire  42  extends distal to the cam  40  and is attached to the tip protector  18 . The wire  42  may alternately be any rigid structure that fits within the allotted space in the housing  14  and is moveable between a first position and a second position. Furthermore, the wire  42  can be made out of a variety of materials such as metal or plastic. 
     Referring also to  FIG. 4 , the tip protector  18  is held by the lumen of the needle  16 . The tip protector  18  is extendable beyond the tip  24  of the needle  16  to prevent the sharp tip  24  of the needle  16  from contacting the back wall of the vessel after initial penetration. The tip protector  18  is atraumatic to prevent injury to the back wall of the vessel. The back wall of the vessel is the wall of the vessel substantially opposite to the penetration made by the needle  16 . The tip protector  18  has a circular cross-section with a substantially rounded end, but may have a different cross-sectional geometry if desired. A variety of different materials may be used to form the tip protector  18 , including metal, plastic, ceramic, or rubber. Additionally, the tip protector  18  may be a coating created on the surface of the wire  42 . Both the cam  40  and the wire  42  move together in a substantially linear motion to control the extension of the tip protector  18  from the tip  24  of the needle  16 . 
     The tip protector  18  is located on the distal end of the wire  42  such that it extends past the tip  24  of the needle  16  when the spring  34  is in its relaxed state in a first position. When the button  22  is undepressed, the tip protector  18  is in the first position, at least partially outside but still coaxial with the lumen of the needle  16 . When the button  22  is depressed, the tip protector  18  is moved to a second position substantially within the lumen of the needle  16 . 
     Referring to  FIG. 2 , the tool  10  is positioned on the target vessel  12  immediately prior to penetration. Referring also to  FIG. 1A , when the user pushes the button  22 , the cam  40  moves proximally, thereby retracting the tip protector  18  into the needle  16  and exposing the sharp tip  24 . The user then advances the entire tool  10  such that the sharp tip  24  penetrates the vessel wall  12 . Vessel penetration may be confirmed visually by a small amount of blood or other fluids exiting the proximal end of the needle  16 . Referring to  FIG. 3 , the button  22  is then released to allow the tip protector  18  to extend beyond the sharp tip  24  of the needle  16 . This is desirable so as to prevent accidental penetration through the back wall of the vessel should the tool be advanced too far into the vessel. Referring back to the side cross-sectional view of  FIG. 1A , the spring  34  returns to its normal, uncompressed state when the button  22  is released, thus causing the cam  40  and wire  42  to move distally and causing the tip protector  18  to extend past the tip  24  of the needle  16 . Alternatively, the tip protector  18  may initially be retracted into the needle  16  and released or extended manually by the user following penetration into the vessel. 
     Referring to  FIG. 4 , the needle  16  is substantially coaxial with the wire  42  with a gap between them to accommodate the tip protector  18  attached to the wire  42 . The outer diameter of the tip protector  18  may be substantially equal to the inner diameter of the needle  16 , with adequate clearance between to allow the tip  18  to slide within the lumen of the needle  16 . A cutting member  26  is held in and is moveable along the slot  25 , the slot  25  serving to guide the cutting member  26  as it moves through the vessel and creates the incision. The slot  25  is substantially the same width as the cutting member  26  so as to maintain substantially linear movement of the cutting member  26  along the axis of the needle  16 . 
     Referring to  FIGS. 1A ,  4 , and  5 , the needle  16  is inserted into the vessel  12 . After the button  22  has been released to extend the tip protector  18 , the surgeon actuates the cutting member  26  by using a second user input feature such as a slider  20  located at the distal end of the tool  10 . The slider  20  is attached to the cutting member  26  such that moving the slider  20  translates the cutting member  26  along the slot  25  in the needle  16 . Referring to  FIG. 1A , an arched portion  48  on the slider  20  grips a tab  50  that is connected to the cutting member  26  such that linear movement of the slider  20  corresponds directly with linear movement of the cutting member  26  to create an incision in the vessel wall. Alternatively, the slider  20  may directly engage the cutting member  26  in a different way, or may indirectly engage the cutting member  26  such as by a linkage. The cutting member  26  has a nose  52  that engages the upper surface of the vessel while a sharpened edge  54  immediately beneath the nose  52  cuts through the vessel wall. The cutting member  26  may be made out of metal, ceramic, or other material whose edge can be made sharp. Referring also to  FIG. 3 , the tab  50  travels within a slot  21  in the tool housing  14  between an initial starting position and a final position. Additionally, there may be grooves  23  on either or both sides of the slot  23  to serve as tracks corresponding to features that may be present on the underside of the slider  20  to help guide the slider  20  as the surgeon creates the incision. the slider  20  is shown in the initial position. Referring to  FIG. 6 , the slider  20  is shown moved to the final position as the tool  10  is held within the vessel  12 . Since the slot  21  is of a predefined length, the incision that is created by the cutting member  20  as the slider  20  is moved from the initial position to the final position will be of a known length and no measurements are needed on the part of the surgeon prior to or during the procedure. 
     Referring to  FIG. 7 , the cutting member  26  is shown fully deployed. The tool  10  is then removed from the newly created incision. Where the incision is an arteriotomy performed before anastomosis, a graft vessel is attached to complete the anastomosis. 
     While the invention has been described in detail, it will be apparent to one skilled in the art that various changes and modifications can be made and equivalents employed, without departing from the present invention. For example, while the tool has been described in terms of cutting a blood vessel, other tissue could be cut with it as well. It is to be understood that the invention is not limited to the details of construction and/or the arrangements of components set forth in the above description or illustrated in the drawings. Therefore, the invention is not to be restricted or limited except in accordance with the following claims and their legal equivalents.