Abstract:
The present invention relates to an innovative roller cutting device, cutting template and method for cutting a tissue pattern. The invention allows a precise tissue pattern to be cut without dragging the material and possibly tearing the tissue as would often occur using a straight scalpel blade. The roller cutter and template described herein can be used for numerous surgical applications requiring precise cutting of tissue and other materials.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/283,401, filed Apr. 12, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention pertains to the field of surgical instruments. More particularly, this invention relates to a roller cutting device, cutting template and a method for cutting tissue.  
         BACKGROUND OF THE INVENTION  
         [0003]    To overcome disadvantages of the prior methods of valve reconstruction, Cardiomend LLC (the assignee of the present application), developed improved, more easily reproducible, less complicated, and generally standardized, methods of reconstructing heart valves. These methods are generally described in Love U.S. Pat. Nos. 5,716,399, Love 6,129,758, and copending U.S. application Ser. No. 09/330,689 (the “Love patents”), each of which is incorporated herein by reference in its entirety. The Love patents generally describe a method for reconstructing semilunar valves using a novel unitary trefoil tissue pattern preferably of lightly tanned autologous pericardium. This method preferably includes the steps of (a) sizing of the heart valve based on the distance between adjacent commissures of the native valve annulus; (b) cutting a trefoil tissue pattern corresponding in size to the native valve annulus; (c) temporarily mounting the tissue pattern on a surgical instrument for holding the tissue in a configuration of a circulatory system valve to facilitate attachment of the tissue; and (d) suturing the tissue to the native valve annulus.  
           [0004]    The present invention relates to an innovative roller cutting device, cutting template and cutting method particularly adapted for cutting a tissue pattern for use in the method described in the Love patents. Among the advantages of the present invention is that it allows a precise tissue pattern to be cut without dragging the material and possibly tearing the tissue as would often occur using a straight scalpel blade. The roller cutter and template described herein can also be used for numerous other surgical applications requiring precise cutting of tissue and other materials.  
         SUMMARY OF THE INVENTION  
         [0005]    The invention includes a tissue cutting device for use with a scalpel handle. The scalpel handle is preferably a conventional handle having a ridge on which a blade can be mounted. The cutting device includes a rotary blade rotatively attached to a blade holder. The blade holder has slot therein. The slot allows the holder to be attached to the scalpel handle by inserting the ridge of the handle into the slot of the holder.  
           [0006]    The invention also includes a template for cutting a piece of tissue into a desired pattern. The template has a base and a cover. The base has one or more channels therein corresponding in shape to the desired pattern. The piece of tissue can be placed between the base and the cover and cut into the desired pattern using the channels as a guide.  
           [0007]    In one embodiment, the one or more channels comprise an inner channel and an outer channel sized to correspond to the geometry of a heart valve. The outer channel conforms to the size and shape of the valve annulus and the inner channel conforms to the size and shape of the valve orifice.  
           [0008]    A kit can be provided for cutting a piece of tissue into a desired pattern. The kit includes a tissue cutting device having a rotary blade and a template. The template has a base and a cover. The cover has one or more channels therein corresponding in shape to the desired pattern. The piece of tissue is placed between the base and the cover and cut into the desired pattern by guiding the rotary blade through the channels. The rotary blade is preferably sized to fit within the channels such that the lateral movement of the blade within the channels is limited to provide an even, accurate cut. 
       
    
    
     DRAWINGS  
       [0009]    These, and other features, aspects and advantages of the present invention will become more fully apparent from the following detailed description, and accompanying drawings where:  
         [0010]    [0010]FIG. 1 is a side perspective view of a roller cutter;  
         [0011]    [0011]FIG. 2A is a side view of a roller cutter;  
         [0012]    [0012]FIG. 2B is a front sectional view of the rivet and blade of a roller cutter taken along line A-A in FIG. 2A;  
         [0013]    [0013]FIG. 3A is a side view of a roller cutter;  
         [0014]    [0014]FIG. 3B is a sectional view of the rivet and blade of a roller cutter taken along line A-A in FIG. 3A;  
         [0015]    [0015]FIG. 4 is a side view of a blade holder of a roller cutter;  
         [0016]    [0016]FIG. 5A is a side view of a rotary blade of a roller cutter;  
         [0017]    [0017]FIG. 5B is a front view of a rotary blade of a roller cutter;  
         [0018]    [0018]FIG. 6A is a side view of a rivet of a roller cutter;  
         [0019]    [0019]FIG. 6B is a front view of a rivet of a roller cutter;  
         [0020]    [0020]FIG. 6C is a front sectional view of a rivet of a roller cutter taken along line B-B in FIG. 6A;  
         [0021]    [0021]FIG. 7A is a side view of a roller cutter and a standard scalpel blade handle for use therewith;  
         [0022]    [0022]FIG. 7B is a prospective view of a roller cutter with attached scalpel handle used with a cutting template;  
         [0023]    [0023]FIG. 8A is a front view of an open cutting template for cutting a trefoil tissue pattern for semilunar valve reconstruction;  
         [0024]    [0024]FIG. 8B is a front perspective view of an open cutting template for cutting a trefoil tissue pattern for semilunar valve reconstruction; and  
         [0025]    [0025]FIG. 8C is a back perspective view of an open cutting template for cutting a trefoil tissue pattern for semilunar valve reconstruction. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0026]    The subject invention provides new, useful and unique devices and method for cutting tissue. The instruments and method are particularly suited for cutting tissue for reconstruction of cardiac semilunar valves (aortic and pulmonic) utilizing the methods described in Love patents incorporated herein by reference.  
         [0027]    As shown in FIGS. 1, 2A,  2 B,  3 A, and  3 B, the roller cutter comprises the following principal parts: a rotary blade  10 , a blade holder  14  for holding the blade  10 ; and a rivet  12  for attaching the blade  12  to the holder  14  such that blade  10  can rotate about rivet  12 . All parts are preferably constructed of stainless steel so that the device can be readily sterilized and discarded after single use.  
         [0028]    An embodiment of blade holder  14  is illustrated in FIG. 4. Holder  14  comprises a slot  16 , which is preferably sized to allow holder  14  to be attached to a standard scalpel handle as illustrated in FIGS. 7A and 7B. Blade holder  14  also comprises a circular opening  18  for receiving rivet  12 . The blade holder  14  is preferably constructed from an approximately 0.015 inch sheet of 440A stainless steel.  
         [0029]    An embodiment of rotary blade  10  is illustrated in FIGS. 5A and 5B. Blade  10  is circular and preferably includes a circular center opening  20  for receiving rivet  12 . Blade  10  also includes an outer center sharpened rim  22 , which is preferably cut or ground to an angle of approximately 22 degrees from each side surface of blade  10 . Blade  10  is preferably has a diameter of about 0.394 inch and is constructed of 440A stainless steel.  
         [0030]    An embodiment of rivet  12  is illustrated in FIGS. 6A, 6B, and  6 C. Rivet  12  preferably comprises cylindrical blade hub  26  which fits inside opening  20  of blade  10 . Rivet  12  also includes cylindrical outer hub  28  which fits inside opening  18  of blade holder  14  to allow blade  10  to be rotatively mounted to holder  14 . Outer hub  28  preferably includes a recessed area  30  for receiving a retainer for securing rivet  12  to holder  14 . Rivet  12  further includes disk  24  for securing the rotary blade  10  on blade hub  26  such that blade  10  can rotates about rivet  12  at blade hub  26 .  
         [0031]    The roller cutter is designed to be used to cut precise geometric patterns used, for example, for heart valve reconstruction. As shown in FIG. 7A, the roller cutter  30  can preferably be used with a standard scalpel handle  32  by attaching holder  14  to the scalpel handle  32  using snap-on slot  16 . As shown in FIG. 7B, the roller cutter  30  is used in a preferred embodiment to cut tissue into a precise geometric pattern for use in semilunar heart valve reconstruction using a cutting template  33 .  
         [0032]    [0032]FIGS. 8A, 8B and  8 C show an embodiment of a cutting template  33  for use with the roller cutter  30  for cutting a trefoil tissue pattern for semilunar heart valve reconstruction as is fully described in the Love patents. The template  33  preferably comprises a cover  34  and a base  36 , connected by a hinge  38 . Cover  34  has an outer channel  40  and an inner channel  42  forming the shape of the preferred tissue pattern. Channels  40  and  42  are preferably sized to correspond to the expected geometry of a native heart valve based upon measurements taken from the native valve annulus, and is preferably provided in various sizes to correspond to a range of typical annulus sizes (e.g., 6 templates can be provided corresponding to valve diameters of 19-29 mm in 2 mm increments). Outer channel  40  conforms to the expected size and shape of the valve annulus and inner channel  42  conforms to the expected size shape of the valve orifice. Inner channel  42  preferably includes rounded corners  44   a ,  44   b  and  44   c  in which a standard dermal biopsy punch can be inserted to facilitate cutting of the corner areas of the tissue pattern, which may be difficult to reach using the circular blade  10  of the roller cutter. Cover  34  also preferably includes a textured cover label  46 , which is adhered to the inside surface of cover  34  to hold together the portions of cover  34  that are separated by channels  40  and  42 . Cover label  46  is preferably constructed using biocompatible paper or plastic materials that can readily be cut through and includes a texturing (e.g., dimpling) to help hold the tissue in place. Base  36  also preferably includes a textured area  48  to help hold the tissue in place. Base  36  also preferably includes a pattern outline  50  of the trefoil tissue pattern mirroring outer channel  40  to provide a visual indication on base  36  of the minimum size of tissue needed to form the desired pattern. A locking mechanism  52  (e.g., a clip) on base  36  preferably cooperates with a locking mechanism  54  (e.g., a small hole) on cover  34  to secure the cover  34  and base  36  in the closed position.  
         [0033]    The template  33  is used by opening it and placing a piece of tissue on the base  36  that is large enough to cover at least pattern outline  50 . The cover  34  is then closed and secured against base  36  with the tissue piece between the cover  34  and the base  36 . As shown in FIG. 7B, with the template locked in the closed position with tissue between cover  34  and base  36 , blade  10  of roller cutter  30  is inserted into and cuts the tissue along channels  40  and  42 . Blade  10  and disk  24  of rivet  12  are preferably sized to fit into channels  40  and  42  of template cover  34  such that disk  24  acts as a guide limiting the lateral movement of blade  10  within channels  40  and  42  to provide an even, accurate cut. Disk  24  also serves to prevent blade  10  from cutting the edges of template surrounding channels  40  and  42  to avoid possible contamination of the tissue resulting from shaved template particles. The corners of the valve orifice are preferably cut by inserting a standard dermal biopsy punch into corners  44   a ,  44   b , and  44   c . After cutting, the trefoil tissue pattern is preferably removed from the template  33  and placed on a tissue holding instrument to facilitate surgical attachment of the tissue to the native valve annulus as described in the Love patents.  
         [0034]    The many advantages of devices and method described herein include the ability to cut slippery material (such as pericardium tissue) without the movement of material typically experienced when using conventional scalpel blades. The roller cutter cuts with a shearing action. By avoiding dragging movement associated with conventional blades, the roller cutter reduces the risk of uneven cutting of the tissue as a result of blade friction. The roller cutter cuts an extremely clean edge. The roller cutter can be used with standard scalpel handles and can be cost-effectively constructed of materials allowing disposal after a single use.  
         [0035]    Although the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made without departing from the spirit or scope of the invention. For instance, the numerous details set forth herein (e.g., details relating to the presently preferred embodiment of the device for use in connection with semilunar valve reconstruction) are provided to facilitate the understanding of the invention and are not provided to limit the scope of the invention. Those skilled in the art will appreciate that the devices and method described herein are readily adaptable for example for any application requiring the cutting of precise geometric patterns from tissue or other materials. Accordingly, the disclosure of embodiments of the invention is intended to be illustrative of the scope of the invention and is not intended to be limiting.