Abstract:
A cutting instrument comprising: an outer tube; an inner tube rotatably disposed within the outer tube; the inner tube comprising an opening having a leading edge and a trailing edge; and the outer tube comprising a window having a leading edge and a trailing edge; at least one of the leading edge of the opening, the trailing edge of the opening, the leading edge of the window and the trailing edge of the window comprising a canted edge; and the window of the outer tube being adapted to be completely blocked by the inner tube during a phase of the rotation of the inner tube within the outer tube.

Description:
REFERENCE TO PENDING PRIOR PATENT APPLICATION 
       [0001]    This patent application claims benefit of pending prior U.S. Provisional Patent Application Ser. No. 61/994,293, filed May 16, 2014 by Gyrus ACMI, Inc. (d.b.a. Olympus Surgical Technologies America) and Joel A. Willhite et al. for APPARATUS AND METHOD FOR CUTTING TISSUE (Attorney&#39;s Docket No. OLYMPUS-2 PROV), which patent application is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to surgical apparatus and methods in general, and more particularly to surgical apparatus and methods for cutting tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    In many situations, tissue may need to be accessed at a remote surgical site, excised from the adjacent anatomy and then the excised tissue removed from the remote surgical site. By way of example but not limitation, during arthroscopic surgery, endoscopic surgery, ENT surgery, etc., relatively small visualization devices (e.g., “scopes”) and relatively small surgical tools (e.g., graspers, cutters, cauterizers, etc.) are generally introduced into a restricted space within the human body (e.g., the interior of a joint, the interior of the abdomen, the interior of a nasal passage, etc.) and then used at that location for a specific surgical procedure (e.g., to trim meniscal cartilage in a joint, to excise a tissue mass in the abdomen, to excise a tissue mass in a nasal passage, etc.). In many such surgeries, fluid is introduced into the surgical site (and thereafter removed from the surgical site) so as to distend the anatomy for better access and/or visualization (e.g., so as to distend the knee joint for better access and/or visualization), and/or to improve visibility (e.g., so as to flush away blood), and/or to remove debris (e.g., so as to remove severed tissue by suction). 
         [0004]    One of the surgical tools frequently employed in such surgeries is the so-called “powered shaver”. Powered shavers typically comprise an outer tube having a window, and an inner tube rotatably disposed within the outer tube and having an opening, wherein rotation of the inner tube within the outer tube causes the opening of the inner tube to repetitively sweep across the window of the outer tube, whereby to shear off tissue extending into the window of the outer tube. Suction is applied to the interior of the inner tube so as to remove the tissue sheared off by the powered shaver. See, for example, U.S. Pat. No. 4,203,444 (Bonnell et al.) and U.S. Pat. No. 4,867,157 (McGurk-Burleson et al.). 
         [0005]    Unfortunately, current powered shavers tend to suffer from one or more disadvantages. By way of example but not limitation, current powered shavers tend to suffer from small window sizes, which is generally the result of efforts to ensure adequate suction in order to remove sizable debris through the interior of the inner tube. In addition, current powered shavers tend to suffer from inefficient cutting action, which is generally the result of the shearing geometries employed. Among other things, with current powered shavers, the oscillating motion and location of the cutting surfaces tend to “bat” tissue around, in a side-to-side motion. Furthermore, current powered shavers tend to suffer from poor suction, which is generally the result of the geometries used for the window of the outer tube and the opening in the inner tube. 
         [0006]    Thus it would be advantageous to provide a new powered cutter which improves upon the deficiencies of the prior art. Among other things, it would be advantageous to provide a new powered cutter which provides enlarged window sizes, improved cutting action and superior suction. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention comprises the provision and use of a new powered cutter which improves upon the deficiencies of the prior art. Among other things, the new powered cutter provides enlarged window sizes, improved cutting action and superior suction. 
         [0008]    In one form of the invention, there is provided a cutting instrument comprising: 
         [0009]    an outer tube; 
         [0010]    an inner tube rotatably disposed within said outer tube; 
         [0011]    said inner tube comprising an opening having a leading edge and a trailing edge; and 
         [0012]    said outer tube comprising a window having a leading edge and a trailing edge; 
         [0013]    at least one of said leading edge of said opening, said trailing edge of said opening, said leading edge of said window and said trailing edge of said window comprising a canted edge; and 
         [0014]    said window of said outer tube being adapted to be completely blocked by said inner tube during a phase of the rotation of said inner tube within said outer tube. 
         [0015]    In another form of the invention, there is provided a cutting instrument comprising: 
         [0016]    an outer tube; 
         [0017]    an inner tube rotatably disposed within said outer tube; 
         [0018]    said inner tube comprising an opening having a leading edge and a trailing edge; and 
         [0019]    said outer tube comprising a window having a leading edge and a trailing edge; 
         [0020]    at least one of said leading edge of said opening and said trailing edge of said opening comprising a canted edge, and at least one of said leading edge of said window and said trailing edge of said window comprising a canted edge; and 
         [0021]    wherein said at least one canted edge of said opening and said at least one canted edge of said window are canted in the same direction of turn. 
         [0022]    In another form of the invention, there is provided a method for cutting an object, the method comprising: 
         [0023]    providing a cutting instrument comprising:
       an outer tube;   an inner tube rotatably disposed within said outer tube;   said inner tube comprising an opening having a leading edge and a trailing edge; and   said outer tube comprising a window having a leading edge and a trailing edge;   at least one of said leading edge of said opening, said trailing edge of said opening, said leading edge of said window and said trailing edge of said window comprising a canted edge; and   said window of said outer tube being adapted to be completely blocked by said inner tube during a phase of the rotation of said inner tube within said outer tube;       
 
         [0030]    positioning the object in said window; and 
         [0031]    rotating said inner tube within said outer tube. 
         [0032]    In another form of the invention, there is provided a method for cutting an object, the method comprising: 
         [0033]    providing cutting instrument comprising:
       an outer tube;   an inner tube rotatably disposed within said outer tube;   said inner tube comprising an opening having a leading edge and a trailing edge; and   said outer tube comprising a window having a leading edge and a trailing edge;   at least one of said leading edge of said opening and said trailing edge of said opening comprising a canted edge, and at least one of said leading edge of said window and said trailing edge of said window comprising a canted edge; and   wherein said at least one canted edge of said opening and said at least one canted edge of said window are canted in the same direction of turn;       
 
         [0040]    positioning the object in said window; and 
         [0041]    rotating said inner tube within said outer tube. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0042]    These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
           [0043]      FIG. 1  is a schematic view showing a novel powered cutter formed in accordance with the present invention; 
           [0044]      FIGS. 2-5  are schematic views showing the blade assembly of the powered cutter shown in  FIG. 1 ; 
           [0045]      FIG. 6  is a schematic view showing the outer tube of the blade assembly shown in  FIGS. 2-5 ; 
           [0046]      FIGS. 7-9  are schematic views showing the inner tube of the blade assembly shown in  FIGS. 2-5 ; 
           [0047]      FIGS. 10A-10C  are schematic views showing the blade assembly in different states of operation; 
           [0048]      FIGS. 11-14  are schematic views showing alternative constructions for the outer tube of the blade assembly; and 
           [0049]      FIG. 15  is a schematic view showing an alternative construction for the inner tube of the blade assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0050]    The present invention comprises the provision and use of a new powered cutter which improves upon the deficiencies of the prior art. Among other things, this new powered cutter provides enlarged window sizes, improved cutting action and superior suction. 
         [0051]    More particularly, and looking now at  FIG. 1 , there is shown a novel powered cutter  5  formed in accordance with the present invention. Novel powered cutter  5  generally comprises a blade assembly  10  and a handle assembly  15 . As will hereinafter be discussed in further detail, blade assembly  10  is intended to be mated to handle assembly  15  (or another handle assembly) at the time of use, and detached from handle assembly  15  (or another handle assembly) after use (e.g., for cleaning and sterilization, repair or replacement, etc.). Alternatively, blade assembly  10  may be mated to handle assembly  15  (or another handle assembly) at the time of manufacture, e.g., such as in the case of a one-piece disposable system. 
         [0052]    Blade assembly  10  is shown in greater detail in  FIGS. 1-5 . Blade assembly  10  generally comprises an outer tube  20  and inner tube  25  rotatably disposed within outer tube  20 . 
         [0053]    Outer tube  20  is shown in greater detail in  FIGS. 1-6 . Outer tube  20  generally comprises a distal end  35 , a proximal end  40 , and a lumen  45  extending from distal end  35  to proximal end  40 . In one preferred form the present invention, outer tube  20  preferably comprises a closed distal end  48 . 
         [0054]    Outer tube  20  comprises a window  50  comprising a leading edge  55  and a trailing edge  60 . In one preferred form of the invention, leading edge  55  and trailing edge  60  are canted relative to the longitudinal axis  61  of outer tube  20 . In one preferred form of the invention, leading edge  55  and trailing edge  60  have a helical configuration (which may be of constant pitch or non-constant pitch). In another preferred form of the invention, leading edge  55  and trailing edge  60  have a configuration which is a segment of an ellipse. In one preferred form of the present invention, outer tube  20  also comprises a first edge  65  connecting leading edge  55  to trailing edge  60 , and a second edge  70  connecting leading edge  55  to trailing edge  60 . In one preferred form of the invention, leading edge  55 , trailing edge  60 , first edge  65  and second edge  70  form a prismatic section of a parallelogram. 
         [0055]    Inner tube  25  is shown in greater detail in  FIGS. 1-5  and  7 - 9 . Inner tube  25  generally comprises a distal end  75 , a proximal end  80 , and a lumen  83  extending from distal end  75  to proximal end  80 . In one preferred form of the present invention, inner tube  25  preferably comprises a closed distal end  84 . 
         [0056]    Inner tube  25  comprises an opening  85  comprising a leading edge  90  and a trailing edge  95 . In one preferred form of the invention, leading edge  90  and trailing edge  95  are canted relative to the longitudinal axis  96  of inner tube  25 . In one preferred form of the invention, leading edge  90  and trailing edge  95  have a helical configuration (which may be of constant pitch or non-constant pitch). In another preferred form of the invention, leading edge  90  and trailing edge  95  have a configuration which is a segment of an ellipse. 
         [0057]    It should be appreciated that leading edge  90  of inner tube  25  extends at an angle to trailing edge  60  of outer tube  20 , and/or trailing edge  95  of inner tube  25  extends at an angle to leading edge  55  of outer tube  20 , so as to create a shearing action between such surfaces (i.e., edges) when inner tube  25  is rotated relative to outer tube  20 , as will hereinafter be discussed. 
         [0058]    Inner tube  25  is rotatably disposed within outer tube  20  such that rotation of inner tube  25  within outer tube  20  causes opening  85  of inner tube  25  to repetitively sweep across window  50  of outer tube  20 , whereby to shear off tissue extending into window  50  of outer tube  20 . More particularly, in accordance with the present invention, as inner tube  25  is rotated within outer tube  20 , leading edge  90  of inner tube  25  is swept across trailing edge  60  of outer tube  20  or, depending on the direction of rotation of inner tube  25  relative to outer tube  20 , trailing edge  95  of inner tube  25  is swept across leading edge  55  of outer tube  20 , so as to create a shearing action at the interface of leading edge  90  of inner tube  25  and trailing edge  60  of outer tube  20 , or at the interface of trailing edge  95  of inner tube  25  and leading edge  55  of outer tube  20 . This shearing action serves to cut away tissue extending into window  50  of outer tube  20 . It should be appreciated that this shearing action is superior to the cutting action of conventional powered cutters due to the moving point contact of the shearing (“scissoring”) surfaces (i.e., edges). In addition, this shearing action is superior to the cutting action of conventional powered cutters, inasmuch as the cutting forces of novel powered cutter  5  are generally directed proximally or distally, rather than laterally (as is the case where the side edges of windows are used for cutting). Directing the cutting forces proximally or distally, rather than laterally, can help the surgeon keep the powered cutter in the desired position and also help keep tissue from being “batted” around, in a side-to-side motion, during cutting. Suction applied to lumen  83  of inner tube  25  removes the excised tissue from blade assembly  10 . 
         [0059]    If desired, space can be provided between inner tube  25  and outer tube  20  so as to allow irrigation to be supplied to the surgical site. 
         [0060]    In one preferred form of the invention, inner tube  25  is configured to completely block window  50  of outer tube  20  during a phase of the rotation of inner tube  25  within outer tube  20 . As a result, larger window sizes can be used while still providing superior suction for the blade assembly. 
         [0061]    In one preferred form of the invention, and looking now at  FIGS. 10A ,  10 B and  10 C, blade assembly  10  can be considered to assume three different “states” as inner tube  25  rotates within outer tube  20 , i.e., a “window fully open” state ( FIG. 10A ) where suction is used to facilitate tissue engagement, a “resecting” state ( FIG. 10B ) where the surfaces (i.e., edges) of inner tube  25  and outer tube  20  cooperate to provide a scissoring action so as to cut tissue extending into window  50  of outer tube  20 , and a “window fully closed” state ( FIG. 10C ) where inner tube  25  substantially completely closes off window  50  of outer tube  20 , thereby allowing for maximum inner lumen suction to rid the cutting area of tissue and fluid. 
         [0062]    As shown in  FIG. 1 , blade assembly  10  is intended to be mated to handle assembly  15  (or another handle assembly) at the time of use, and detached from handle assembly  15  (or another handle assembly) after use (e.g., for cleaning and sterilization, repair or replacement, etc.). Alternatively, blade assembly  10  may be mated to handle assembly  15  (or another handle assembly) at the time of manufacture, e.g., such as in the case of a one-piece disposable system. Handle assembly  15  is provided with a housing  100  for securely mounting the distal end  40  of outer tube  20 , and means for coupling a drive shaft  105  to inner tube  25 , e.g., a connector  115  which is secured to drive shaft  105  and inner tube  25 . Preferably connector  115  is provided with appropriate ports so that the interior of inner tube  25  is in fluid communication with a suction port  120 , whereby to provide suction to blade assembly  10 . 
         [0063]    It should be appreciated that handle assembly  15  shown in  FIG. 1  is provided by way of example but not limitation, and other handle assemblies may be used in conjunction with blade assembly  10 . 
         [0064]      FIGS. 11-14  show alternative configurations for outer tube  20  and its window  50 . 
         [0065]    More particularly, in  FIG. 11 , window  50  is constructed so that its leading edge  55  extends perpendicular to the longitudinal axis of outer tube  25  and its trailing edge  60  is canted relative to the longitudinal axis  61  of outer tube  25 , with first edge  65  and second edge  70  extending between leading edge  55  and trailing edge  60 . 
         [0066]    In  FIG. 12 , window  50  is constructed so that its leading edge  55  and its first edge  65  and second edge  70  combine to form an arcuate surface (i.e., edge), and its trailing edge  60  is canted relative to the longitudinal axis  61  of outer tube  25 . 
         [0067]    In  FIG. 13 , window  50  is constructed so that its leading edge  55  and its first edge  65  combine to form an arcuate surface (i.e., edge), its trailing edge  60  is canted relative to the longitudinal axis  61  of outer tube  25 , and its second edge  70  extends between leading edge  55  and trailing edge  60 . 
         [0068]    In  FIG. 14 , window  50  is constructed so that its leading edge  55  and its trailing edge  60  are canted in opposite directions relative to the longitudinal axis of outer tube  25 , with first edge  65  and second edge  70  extending between leading edge  55  and trailing edge  60 . 
         [0069]      FIG. 15  shows an alternative configuration for inner tube  25  and its opening  85 , wherein leading edge  90  extends perpendicular to the longitudinal axis of inner tube  25  and trailing edge  95  has a helical configuration. 
         [0070]    The powered shaver of the present invention improves upon the deficiencies of the prior art. Among other things, the new powered cutter provides enlarged window sizes, improved cutting action and superior suction. 
       Modifications of the Preferred Embodiments 
       [0071]    It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.