Abstract:
A surgical tool arrangement for performing endoscopic surgical procedures which includes a powered handpiece and a cutting accessory which detachably connects to the handpiece. The cutting accessory has a distal end which defines a cutting head incorporating a suction arrangement directly adjacent the cutting features thereof.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/791,527, filed Mar. 15, 2013, which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention generally relates to a surgical tool arrangement useful for performing endoscopic surgical procedures which includes a powered handpiece and, more particularly, to a cutting accessory which detachably connects to the handpiece and incorporates a suction arrangement at the distal end of the cutting accessory directly adjacent the cutting features thereof. 
     BACKGROUND OF THE INVENTION 
     Endoscopic surgical procedures are routinely performed in order to accomplish various surgical tasks. In such a surgical procedure, small incisions or portals are made in the patient. An endoscope, which is a device that allows medical personnel to view the surgical site, is inserted in one of the portals. Surgical instruments used to perform other tasks are inserted into other portals. The surgeon views the surgical site through the endoscope to determine how to manipulate the surgical instruments in order to accomplish the desired procedure. An advantage of performing endoscopic surgery is that, since the portions of the body that are cut open are minimized, the portions of the body that need to heal after the surgery are likewise reduced. Moreover, during an endoscopic surgical procedure, only relatively small portions of the patient&#39;s internal organs and tissue are exposed to the open environment. This minimal opening of the patient&#39;s body lessens the extent to which the organs and tissue are open to infection. 
     The ability to perform endoscopic surgery is enhanced by the development of powered surgical tools especially designed to perform such procedures. Once such tool is sold by the assignee hereof under the trademark FORMULA®. This tool is in the form of a cylindrical handpiece designed to be held in the hand of the surgeon. The handpiece has a front or distal end provided with a coupling assembly for releasably holding a cutting accessory, and a motor disposed within a handpiece housing which drives the accessory. The cutting accessories, such as shavers, drills and burs, include a hub which defines the proximal end of the accessory and is appropriately configured to cooperate with the coupling assembly of the handpiece to lock the accessory thereto, an elongated and tubular housing element having a proximal end fixed to the hub, and an elongated cutting element including a drive shaft disposed within the housing element. When the accessory is attached to the handpiece, the handpiece motor couples to the drive shaft of the accessory and moves same relative to the outer housing element. The handpiece motor is selectively actuable to drive the accessory drive shaft so as to cause a desired cutting action at the distal end of the accessory. The handpiece is associated with a control unit which controls the functioning thereof, and is actuated by the user via appropriate buttons provided on the handpiece itself, at the control unit or through use of a footswitch. 
     In an endoscopic surgical procedure, irrigating fluid is introduced into the surgical site. This fluid serves as a transport media for removing tissue and debris from the surgical site. In order to remove the irrigating fluid and the material contained therein, the above handpiece and the various accessories which are usable therewith together define a suction conduit. A suction pump is connected to the handpiece to provide the suction force needed for drawing the fluid and material away from the surgical site. In order to control the suction flow through the accessory and the handpiece, the handpiece is typically provided with a manually operated valve which is manipulated by the surgeon to control suction of material away from the surgical site. 
     Mechanical cutting accessories, such as the shaver, drill and bur discussed above, are commonly used in arthroscopic procedures, and allow for the resection of hard and soft bodily tissues, for example, those found within the knee, shoulder and other joints. A bur-type cutting accessory is commonly used to resect bone or other hard tissues, and includes cutting features which when rotated serve to cut away targeted bone or hard tissue. Such cutting features may be helically-oriented or non-helically oriented. The cutting element of a bur-type cutting accessory includes a cutting head with these cutting features which are exposed through a window formed at the distal end of the outer housing element when the cutting element is located therein. In some bur-type cutting accessories, the window formed in the outer housing element opens primarily sidewardly, so that the distal end of the outer housing element covers a portion or one side of the cutting head of the bur to allow the user to better target bone or hard tissue. Alternatively, the entire cutting head geometry may project distally beyond the terminal end of the outer housing element, and this type of bur configuration is often called “unhooded”. Many bur configurations are for removal of particular bone or hard tissue types, and a variety of different bur geometries are available to specifically address the type of cutting the accessory is to carry out. 
     Further, in some conventional bur-type cutting accessories, the cutting element includes an elongate and hollow tubular drive shaft and the cutting head at the distal end thereof is provided as a solid member which is fixedly mounted to the distal end of the drive shaft. In order to draw suction through the cutting element in this type of accessory, the distal end of the drive shaft is provided with a suction opening which opens sidewardly outwardly and communicates with the hollow interior of the drive shaft. In operation, bone or other hard tissue removed or cut away by the cutting head is suctioned into the hollow interior of the drive shaft through the window of the outer housing element. Bur-type cutting accessories, due to their configuration, often spray surgical debris outwardly and away from the cutting features of the cutting head. Eventually, the surgical debris will be evacuated from the surgical site through the suction opening located proximally from the cutting head of the bur. However, in the interim, the debris can occlude the surgeon&#39;s field of view. 
     The cutting accessory disclosed in U.S. Pat. No. 5,489,291 includes an abrading element which is generally hollow and includes a plurality of helically-oriented apertures, each of which apertures is disposed between an adjacent pair of abrading ridges. These helically-oriented apertures provide a path for fluid and abraded tissue into the central bore of the tool. However, the configuration of the abrading element is primarily hollow, and the suction apertures are elongate and extend a substantial longitudinal distance along the abrading element, and such an open configuration compromises the structural integrity of the abrading element. Further, the suction apertures and the abrading ridges are formed together or at the same time, which necessarily limits the design flexibility of both the abrading ridges and the suction apertures. 
     While the arrangements described above serve to remove fluid and surgical debris from the surgical site, there is a continuing desire and need for improved performance in surgical tools in an effort to minimize trauma to the patient and to make the operative procedure more efficient and effective. The surgical accessory according to the invention includes a cutting element with a cutting head which incorporates one or more suction openings directly adjacent the cutting features of the cutting head. In one embodiment, the cutting head has a generally helically oriented cutting edge, and a suction opening or alternatively a plurality of openings in communication with a source of suction, are located directly adjacent the cutting edge. Another embodiment of the invention includes a cutting head with a cutting edge and a suction opening which traverses the cutting edge. A further embodiment of the invention includes a cutting head with a cutting edge which is generally straight or linear and a suction opening or a plurality of suction openings disposed directly adjacent the cutting edge. 
     The placement of the suction opening or openings according to the invention serves to evacuate surgical debris from the surgical site rapidly after the debris is generated and thus results in a much reduced delay between the time debris is generated and the time the debris is evacuated from the surgical site, thereby preventing or at least minimizing any occlusion of the surgeon&#39;s field of view and providing an overall clearer field of view during use of the accessory. Additionally, the size, placement and process for forming the suction openings allow for a cutting element with increased structural integrity. Further, the suction opening or openings provided in the cutting head in some embodiments are formed in a cutting step which is separate from the cutting step during which the cutting edges or features are formed. Thus, the suction opening or openings can be oriented and/or the size thereof modified without modifying the trajectory and/or configuration of the cutting features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the surgical tool arrangement according to the invention, including a handpiece with a surgical accessory attached thereto; 
         FIG. 2  is an enlarged, fragmentary, longitudinal and cross-sectional view of the handpiece of  FIG. 1  with a surgical accessory attached thereto; 
         FIG. 3  is an enlarged top and fragmentary view of the surgical accessory; 
         FIG. 4  is an enlarged longitudinal cross-sectional view of the surgical accessory of  FIG. 3 , as seen generally along line IV-IV in  FIG. 3 ; 
         FIG. 5  is an enlarged and isolated side view of a first embodiment of the cutting head of the surgical accessory; 
         FIG. 6  is an enlarged and isolated side view of the first embodiment of the cutting head of the surgical accessory rotated approximately 180 degrees from the position shown in  FIG. 5 ; 
         FIG. 7  is an enlarged and isolated side view of the first embodiment of the cutting head of the surgical accessory rotated approximately 90 degrees towards the viewer from the position shown in  FIG. 6 ; 
         FIG. 8  is a cross-sectional view as seen generally along line VIII-VIII in  FIG. 5 ; 
         FIG. 9  is a further enlarged distal end view of the first embodiment of the cutting head of the surgical accessory shown in  FIGS. 5-8 ; 
         FIG. 10  is an enlarged perspective and isolated view of a second embodiment of the cutting head of the surgical accessory; 
         FIG. 11  is an enlarged and isolated side view of the second embodiment of the cutting head of the surgical accessory; 
         FIG. 12  is an enlarged and isolated side view of the second embodiment of the cutting head of the surgical accessory rotated approximately 90 degrees away from the viewer from the position shown in  FIG. 11 ; 
         FIG. 13  is an enlarged and isolated side view of the second embodiment of the cutting head of the surgical accessory rotated approximately 180 degrees from the position shown in  FIG. 11 ; 
         FIG. 14  is an enlarged and isolated side view of the second embodiment of the cutting head of the surgical accessory rotated approximately 180 degrees away from the viewer from the position shown in  FIG. 12 ; 
         FIG. 15  is a cross-sectional view as seen generally along line XV-XV in  FIG. 13 ; 
         FIG. 16  is a further enlarged distal end view of the second embodiment of the cutting head of the surgical accessory shown in  FIGS. 10-15 ; 
         FIG. 17  is an enlarged perspective and isolated view of a third embodiment of the cutting head of the surgical accessory; 
         FIG. 18  is an enlarged and isolated side view of the third embodiment of the cutting head of the surgical accessory; 
         FIG. 19  is an enlarged and isolated side view of the third embodiment of the cutting head of the surgical accessory rotated approximately 90 degrees away from the viewer from the position shown in  FIG. 18 ; 
         FIG. 20  is an enlarged and isolated side view of the third embodiment of the cutting head of the surgical accessory rotated approximately 180 degrees from the position shown in  FIG. 18 ; 
         FIG. 21  is a cross-sectional view as seen generally along line XXI-XXI in  FIG. 20 ; 
         FIG. 22  is a further enlarged distal end view of the third embodiment of the cutting head of the surgical accessory shown in  FIGS. 17-21 ; 
         FIG. 23  is an enlarged perspective and isolated view of a fourth embodiment of the cutting head of the surgical accessory; 
         FIG. 24  is an enlarged and isolated side view of the fourth embodiment of the cutting head of the surgical accessory; 
         FIG. 25  is an enlarged and isolated side view of the fourth embodiment of the cutting head of the surgical accessory rotated approximately 90 degrees away from the viewer from the position shown in  FIG. 24 ; 
         FIG. 26  is an enlarged and isolated side view of the fourth embodiment of the cutting head of the surgical accessory rotated approximately 180 degrees from the position shown in  FIG. 25 ; 
         FIG. 27  is a cross-sectional view as seen generally along line XXVII-XXVII in  FIG. 24 ; 
         FIG. 28  is a further enlarged distal end view of the fourth embodiment of the cutting head of the surgical accessory shown in  FIGS. 23-27 ; 
         FIG. 29  is a further enlarged proximal end view of the fourth embodiment of the cutting head of the surgical accessory shown in  FIGS. 23-27 ; and 
         FIG. 30  is a cross-sectional view of the fourth embodiment of the cutting head of the surgical accessory as seen generally along line XXX-XXX in  FIG. 27 . 
     
    
    
     Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction toward the end of the arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a surgical tool arrangement  10  according to the invention is illustrated. The arrangement  10  includes a handpiece  11 , which at its distal end mounts thereon a surgical accessory  12 . 
     Handpiece  11  is a commercially available surgical handpiece manufactured by the assignee hereof, under Model Nos. 375-704-500 and 375-701-500, and is accordingly only briefly described herein. Handpiece  11  includes an elongate outer housing  13  defining an elongate bore  14  therein. A motor  15  (shown diagrammatically only in  FIG. 1 ) is disposed within housing bore  14 . Motor  15  includes an output or drive shaft  16 , which drive shaft  16  mounts a drive pin  17  at the distal end thereof. A power cable  18  is coupled to the proximal end of handpiece  11  for supplying power to motor  15 . 
     Handpiece housing  13  defines therein an elongate suction bore (not shown) extending generally parallel to and sidewardly of housing bore  14 . This suction bore communicates with a diagonally extending suction passage  20  defined in housing  13 , which passage  20  provides communication between the distal end of housing bore  14  and the suction bore. Suction is drawn through the handpiece  11  by a suction pump (not shown), which is connected to the handpiece  11  via a suction tube  21 . Suction flow through the handpiece  11  is regulated by an adjustable valve  22  having a valve stem (not shown) which is movably mounted in a valve bore  23  defined in housing  13 . The valve  22  is adjusted by the user via a movable handle or arm  24  connected to the valve stem. The above handpiece suction arrangement is described in detail in U.S. Pat. No. 7,682,333 issued on Mar. 23, 2010, which patent is owned by the same assignee hereof and is hereby incorporated by reference herein in its entirety. 
     The accessory  12  is removably attached to the distal end of the handpiece  11  by a coupling assembly  25  provided on the handpiece  11 . Coupling assembly  25  includes a generally ring-shaped collet  26  secured to the distal end of the handpiece housing  13 . A locking ring  27  is movably disposed in collet  26  and is biased to hold the accessory  12  within the housing bore  14  of handpiece  11 . A release button  28  is provided on locking ring  27 , and is used to release the locking ring  27  and allow removal of the accessory  12  from handpiece  11 . Further, a coil  30  is provided in collet  26 , which is used to facilitate inductive signal transfer to/from a radio-frequency identification device (RFID) disposed in the accessory  12  as discussed below. 
     Referring to  FIGS. 2-4 , the accessory  12  will now be described. Accessory  12  defines a central longitudinal axis  31 , and includes an outer cannula or tubular housing element  32  and a tubular cutting element  33  disposed within housing element  32 . Housing element  32  includes a hub  34  which defines the proximal end thereof. Hub  34  is defined by a generally tubular base body  35 , which defines therein a pair of generally rectangular and diametrically-opposed openings  36  adjacent the proximal end thereof. Base body  35  also has formed thereon a pair of outwardly-projecting, diametrically opposed and generally ramp-shaped ears  37  disposed distally of openings  36 . Ears  37  cooperate with coupling assembly  25  of handpiece  11  to secure accessory  12  therein. Hub  34  has a distal end defined by a head  39  or nose of a reduced diameter as compared to base body  35 . Further, hub  34  defines therein a bore  41  which extends completely through the hub  34 , and with which openings  36  of base body  35  communicate. 
     An annular seal  45  is disposed within the proximal end of bore  41  of hub  34 . Seal  45  is constructed of a resilient elastomeric material, and is defined by a main section  46  and axially-spaced proximal and distal sections  47  and  48  disposed at respective opposite ends of the main section  46 . Proximal section  47  defines thereon a pair of annular ribs  55  and  56 , which are disposed in sealing engagement with an inner annular surface of collet  26  of handpiece  11  when accessory  12  is coupled thereto, as shown in  FIG. 2 . Distal section  48  defines thereon a pair of outwardly projecting and diametrically-opposed lock tabs  57  which engage within the respective openings  36  of hub  34  to secure the seal  45  to hub  34  and fix the axial position of seal  45  relative thereto. Distal section  48  additionally defines thereon a pair of inwardly projecting and diametrically-opposed stop tabs  58 , which are generally radially aligned with the respective lock tabs  57 . As shown in  FIGS. 2 and 4 , an RFID device  59  encapsulated within a ring structure is located within hub bore  41  distally from, and in axially-adjacent relationship with, the distal section  48  of seal  45 . 
     The above-described coupling arrangement of handpiece  11  and the arrangement of the encapsulated RFID device  59  and coil  30  are disclosed in U.S. Pat. No. 7,887,559 issued on Feb. 15, 2011, which patent is owned by the same assignee hereof and is hereby incorporated by reference herein in its entirety. 
     Housing element  32  additionally includes an elongate housing tube  64  which projects distally from hub  34 . More specifically, housing tube  64  has a proximal end which is fixedly mounted within the distal portion of bore  41  of hub  34 . Housing tube  64  defines an elongate bore or conduit  65  therein, in which the cutting element  33  is disposed as discussed below. Referring to  FIGS. 3 and 4 , housing tube  64  has a distal end  66  which in the illustrated embodiment is cut so as to define a window  67  having an annular edge  68 , which window  67  in the illustrated embodiment opens both sidewardly and distally of the tube  64 . Alternatively, the distal end  66  of housing tube  64  may be cut in a manner such that annular edge  68  is oriented perpendicular to the axis  31 . Other configurations of distal end  66  of housing tube  64  are within the scope of the invention, and the above are given only by way of example. 
     Turning now to cutting element  33 , same includes a hub  80  which defines the proximal end thereof. Hub  80  incorporates a motor-engaging drive element  81  defining a proximally opening bore  82 , and a slot  84  which extends transversely to the longitudinal axis of the cutting element  33 . Hub  80  additionally includes a neck  85  which projects distally from drive element  81 . Neck  85  terminates at a head  86  which has an enlarged outer diameter. In this regard, the outer diameter of head  86  is slightly larger than the inward projection of the respective stop tabs  58  of seal  45 . A bore  87  extends through neck  85  and head  86 , in which an elongate and tubular drive shaft  88  is fixed. Drive shaft  88  defines therein a suction passage  89  which is in communication with a suction port  90  defined in neck  85 , which suction port  90  is in turn in communication with suction passage  20  of handpiece  11 . 
     Drive shaft  88  has a distal end  91  which mounts a cutting head  104  thereon. In the illustrated embodiment, the drive shaft  88  and the cutting head  104  are constructed as separate components which are fixed to one another. In this regard, the drive shaft  88  may be constructed of a rigid plastic and then induction welded to the cutting head  104 , which may be constructed of rigid metal, such as stainless steel. Alternatively, the drive shaft  88  and the cutting head  104  may be constructed as an integral or one-piece member formed from rigid metal, such as stainless steel. The cutting head  104  is generally cylindrical and tubular in the illustrated embodiment, and defines a hollow interior  105  which extends along substantially the entire longitudinal extent of cutting head  104 . 
     The cutting head  104  includes a tubular proximal end  106  of a generally constant diameter, a tubular neck portion  107  extending distally from the proximal end  106  and a distal end  109  which extends distally from the distal end of neck portion  107 . As best shown in  FIGS. 5-8 , the neck portion  107  tapers gradually inwardly towards an axis  108  of the cutting head  104  as the neck portion  107  projects away from the proximal end  106 . Distal end  109  is configured for cutting bodily tissue and has a configuration of what is commonly considered a bur. Distal end  109  is defined by a generally cylindrical wall  111  defining an exterior surface  112  extending both circumferentially about and axially along distal end  109  and a plurality of cutting edges  113 . Wall  111  is closed at distal end  109 , as best shown in  FIG. 8 . Cutting edges  113  project outwardly from exterior surface  112  in a direction away from the axis  108 , and additionally extend in a helical manner about the axis  108  along the longitudinal extent of the distal end  109  and in a generally parallel manner with one another along a majority of the longitudinal extent of the distal end  109 . Each cutting edge  113  defines the radially outermost extent of a cutting face  116  formed on the exterior surface  112  of the wall  111 . These cutting edges  113  extend gradually towards one another in the proximal to distal direction and terminate adjacent a tip  117  of the distal end  109 , as best shown in  FIGS. 8 and 9 . The wall  111  includes a plurality of wall segments  118 , each of which extends circumferentially between a pair of circumferentially adjacent cutting edges  113 . Each wall segment  118  thus effectively defines a flute or groove, each of which extends helically about the axis  108  along distal end  109  between a respective pair of cutting edges  113 . It will be appreciated that the cutting edges  113  may alternatively be non-helical or substantially straight so as to extend generally parallel with the axis  108  or so as to be oriented at an angle relative to the axis  108 . The respective wall segments/flutes  118  in this embodiment would thus also be substantially straight. 
     Referring again to  FIGS. 5-9 , the wall  111  of distal end  109  of cutting head  104  defines therein at least one, and in the illustrated embodiment, a plurality, of suction openings  122 . One suction opening  122  is disposed in at least one of the wall segments  118 , and in the illustrated embodiment a plurality of suction openings  122  are disposed in each wall segment  118 . Each suction opening  122  extends completely through the respective wall segment  118  so as to communicate with the hollow interior  105  of cutting head  104 . In the illustrated embodiment, the suction openings  122  of each wall segment  118  are oriented in a longitudinal row  123  closely adjacent one of the cutting edges  113 . More specifically, the suction openings  122  of each row  123  are formed in the cutting head  104 , for example by drilling, so that they follow the helical angle of the respective cutting edge  113  and so that the suction holes  122  lie directly in front of the cutting face  116  of the respective cutting edge  113  when considered the context of the rotational direction of the cutting head  104  during use (as shown by the arrow in  FIG. 5 ). 
     The cutting head  104  of the illustrated embodiment includes a plurality of rows  123  of suction openings  122 , with each row  123  including a plurality of suction openings  122 , and a plurality of cutting edges  113  and corresponding cutting faces  116 . It will be appreciated that the number of cutting edges  113 /cutting faces  116  will vary depending upon the dimensions of the cutting head  104  and/or the type of cutting action desired, and the three cutting edges  113 /cutting faces  116  disclosed herein are presented only as an example of one suitable configuration for a cutting head  104 . Further, each cutting edge  113 /cutting face  116  may have a row  123  of suction openings  122  disposed immediately adjacent thereto as shown herein, or a lesser number of rows  123  may be provided. Additionally, each row  123  may include four suction openings  122  as shown herein, or may include a greater or lesser number of suction openings  122 . Still further, it may be suitable to include one suction opening  122  directly adjacent each cutting edge  113 /cutting face  116 . 
     The cutting element  33  is assembled to the outer tubular housing element  32  by inserting the distal end  91  of drive shaft  88  of cutting element  33  into bore  41  at the proximal end of hub  34 . During this insertion, the enlarged head  86  of hub  80  expands the seal  45  and the head  86  pushes past the stop tabs  58 , at which point the seal  45  essentially resumes its original shape. The stop tabs  58 , while allowing some axial displacement of cutting element  33  relative to housing element  32 , prevent the cutting element  33  from detaching or falling out of the housing element  32  due to gravitational forces. 
     The assembled accessory  12  is secured to the handpiece  11  in a similar manner to that described in the &#39;559 patent referenced above, and will accordingly be only briefly described here. Accessory  12  is attached to handpiece  11  by inserting the hubs  34  and  80  into the open distal end of collet  26 . The ears  37  of hub  34  seat within collet  26 , and the locking ring  27  serves to hold the accessory  12  within handpiece  11 . The above securement of the accessory  12  to handpiece  11  causes the drive element  81  to engage the motor output shaft  16 . More specifically, the drive pin  17  of output shaft  16  seats within slot  84  of drive element  81 , such that the rotational movement of output shaft  16  is transferred to the cutting element  33 . 
     In operation, the distal end of tool  10  is inserted into the surgical site. The cutting element  33  is controlled by a control unit (not shown) connected to handpiece cable  18 , which control unit supplies electrical power to the motor  15  of handpiece  11  in order to actuate cutting element  33  and control the rotational speed thereof. If cutting of tissue is desired, then motor  15  is activated so as to cause cutting element  33  to rotate within and relative to outer housing element  32 . In this regard, it will be appreciated that the control unit may include appropriate control buttons so as to allow the surgeon or operator to select the desired accessory operations. These control functions of the cutting element  33  may alternatively be performed directly from the handpiece  11  which would then include the appropriate control buttons thereon. Alternatively, the control unit may be associated with a switch, either through a suitable cable or wirelessly, to allow the surgeon to operate the controls remotely. Such a switch may be a footswitch or a hand switch. 
     As shown in  FIG. 4 , with the cutting element  33  disposed within housing element  32  and the accessory  12  secured to handpiece  11  as described above, the cutting head  104  is positioned adjacent the window  67  of the housing element  32  so that at least a portion of the cutting head  104  is exposed. In this regard, the cutting head  104  is shown herein as being covered one side thereof by the distal end  66  of the housing element  32 . However, it will be appreciated that other configurations of the housing element distal end  66  are within the scope of the invention. For example, the housing tube  64  of housing element  32  may be provided with a length which allows full exposure of the cutting head  104  axially beyond the distal end  66  of housing tube  64 , so that the cutting head is unhooded or uncovered completely. 
     If desirable or necessary, suction can be provided at the surgical site by manipulating valve  22  on handpiece  11  to draw surgical debris from the surgical site through the suction openings  122  and into the interior  105  of cutting head  104 , into drive shaft suction passage  89 , into handpiece suction passage  20  and proximally through the handpiece  11  towards the suction pump. In this regard, the positioning of the suction openings  122  directly in front of the cutting face  116  of the respective cutting edge  113  provides a direct entry port into the interior  105  of cutting head  104 . More specifically, when the cutting element  33  is rotating and removing tissue during a surgical procedure and suction is applied, bone or other debris generated by the cutting action of the cutting edges  113  is immediately evacuated from the surgical site via the suction openings  122 , into the interior  105  of cutting head  104  and on through the handpiece  11 . This placement of the suction openings  122  can thus prevent or at least minimize occlusion of the surgeon&#39;s field of view by surgical debris. 
     Further, the size and/or number of the suction opening or openings according to the invention are chosen in relation to the size and/or configuration of the cutting features provided on cutting head  104 . More specifically, some cutting features will cause the severing of larger pieces of tissue, which means that the size of the suction opening or openings should be large enough to allow passage of the severed tissue into the cutting head  104 . Likewise, some cutting features will result in the severing of smaller pieces of tissue and thus the suction openings can be smaller and/or lesser in number. 
       FIGS. 10-16  illustrate a second embodiment of the invention which will now be described. Components of the second embodiment which are similar or identical to components of the first embodiment will include the same reference numbers as in the prior embodiment plus “100”, and a detailed description of all components will accordingly not be provided. The cutting head  204  according to the second embodiment is generally cylindrical and tubular, and defines a hollow interior  205  which extends along substantially the entire longitudinal extent of the cutting head  204 . The cutting head  204  includes a tubular proximal end  206  of a generally constant diameter, a tubular neck portion  207  extending distally from the proximal end  206  and a distal end  209  which extends distally from the distal end of neck portion  207 . The neck portion  207  tapers gradually inwardly towards an axis  208  of the cutting head  204  as the neck portion  207  projects away from the proximal end  206 . Distal end  209  is configured for cutting bodily tissue and is defined by a generally cylindrical wall  211  defining an exterior surface  212  extending both circumferentially about and axially along distal end  209 , and a plurality of cutting edges  213 . Wall  211  is closed at the distal end  209 , as best shown in  FIGS. 15 and 16 . The cutting edges  213  project outwardly from exterior surface  212  in a direction away from the axis  208 , and additionally extend in a helical manner about the axis  208  along the longitudinal extent of the distal end  209  and in a generally parallel manner with one another along a majority of the longitudinal extent of the distal end  209 . Each cutting edge  213  defines the radially outermost extent of a corresponding cutting face  216  formed on the exterior surface  212  of the wall  211 . These cutting edges  213  extend gradually towards one another in the proximal to distal direction and terminate adjacent a tip  217  located on the distal end  209 . The wall  211  includes a plurality of wall segments  218 , each of which is positioned circumferentially between a pair of circumferentially adjacent cutting edges  213 . Each wall segment  218  thus effectively defines a flute or groove, each of which extends helically about the axis  208  along distal end  209  between a respective pair of cutting edges  213 . 
     The cutting head  204  of the second embodiment includes a pair of suction openings  222  located on opposite sides of the distal end  209  of the cutting head  204 . One method of forming the suction openings  222  is to cut an elongated groove or grooved area  219  into the material of the distal end  209  of the cutting head  204  separately from the cutting process for forming the grooves or flutes  218  of the cutting head  204 . In this regard, the grooved area  219  can, in one embodiment, be formed prior to the grooves/flutes  218 . The grooved areas  219  are formed on opposite sides of the cutting head  204  and are oriented transversely relative to one another. This cutting process results in elongated or generally elliptically-shaped suction openings  222  located at the bottom of each grooved area  219 . In the illustrated embodiment and as best shown in  FIG. 11 , each grooved area  219  and thus each corresponding suction opening  222  is oriented transverse to the axis  208  of the cutting head  204 , and transverse to a cutting edge  213 . The suction openings  222  thus interrupt the corresponding cutting edge  213 . However, given that there is some overlap between an end of one cutting edge  213  and the beginning of the adjacent or next cutting edge  213 , a smooth-cut finish can be achieved even with this interruption. 
     The suction openings  222  need not be provided in directions transverse to the respective cutting edges  213  as described above, and instead may be provided within the respective wall segments  218 , as shown in dotted lines in  FIG. 12 . In other words, the suction openings  222  can be aligned with or primarily located in the wall segments/flutes  218 . 
     Each suction opening  222  extends completely through the respective wall  211  so as to communicate with the hollow interior  205  of the cutting head  204 . In the illustrated embodiment, the suction openings  222  traverse the respective cutting edge  213 , and thus are located directly where tissue is being excised. In the alternative embodiment illustrated in dotted lines in  FIG. 12  as discussed above, the suction opening or openings  222  lie directly in front of the cutting face  216  of the respective cutting edge  213  when considered the context of the rotational direction of the cutting head  204  during use. This orientation of the suction openings  222  provides a direct entry port into the interior  205  of the cutting head  204  so that bone or other debris generated by the cutting action of the cutting edges  213  is immediately evacuated from the surgical site via the suction openings  222 . Further, by forming the suction openings  222  and the grooves/flutes  218  in separate cutting or process steps as discussed above, the orientation and/or the size of the respective suction openings  222  can be modified without modifying the configuration and/or trajectory of the cutting edges  213 . 
       FIGS. 17-22  illustrate a third embodiment of the invention. Components of this third embodiment which are similar or identical to components of the first embodiment will include the same reference numbers as in the prior embodiment plus “200”. The primary difference between the third embodiment as shown in  FIGS. 17-22  and the second embodiment discussed above is that a single suction opening  322  is provided as compared to the two suction openings  222  included in the second embodiment. In this regard, the cutting head  304  includes a suction opening  322  located on one side of the distal end  309  thereof. In the illustrated embodiment, the suction opening  322  is formed by cutting an elongated groove or grooved area  319  into the material of the distal end  309  of the cutting head  204  separately from the cutting process or step which forms the grooves or flutes  318  of the cutting head  304 . As is the case with the second embodiment, the grooved area  319  is oriented transversely relative to the axis  308  of the cutting head  304 , and transverse to a cutting edge  313 . The suction opening  322  thus interrupts the corresponding cutting edge  313 . As discussed above, it will be appreciated that the suction opening can alternatively be provided primarily within the respective wall segments/flutes  318 , as shown in dotted lines in  FIG. 12 . 
       FIGS. 23-29  illustrate a fourth embodiment of the invention. Components of this fourth embodiment which are similar or identical to components of the first embodiment will include the same reference numbers as in the prior embodiment plus “300”. The cutting head  404  according to the fourth embodiment is generally cylindrical and tubular, and defines a hollow interior  405  which extends along substantially the entire longitudinal extent of the cutting head  404 . The cutting head  404  includes a tubular proximal end  406  of a generally constant diameter, a tubular neck portion  407  extending distally from the proximal end  406  and a spherical distal end  409  which extends distally from the distal end of neck portion  407 . Distal end  409  is configured for cutting bodily tissue and is defined by a generally cylindrical and spherical wall  411  defining an exterior surface  412  extending both circumferentially about and axially along the distal end  409 , and a plurality of cutting edges  413 . The cutting edges  413  project outwardly from exterior surface  412  in a direction away from the axis  408 , and additionally extend in a generally linear manner in the proximal to distal direction along the longitudinal extent of the distal end  409  and in a generally parallel manner with one another along a majority of the longitudinal extent of the distal end  409 . Each cutting edge  413  defines the radially outermost extent of a corresponding cutting face  416  formed on the exterior surface  412  of the wall  411 . These cutting edges  413  extend gradually towards one another in a proximal to distal direction and terminate adjacent a tip  417  of the distal end  409 . The wall  411  includes a plurality of wall segments  418 , each of which is positioned circumferentially between the cutting edges  413 . 
     The cutting head  404  includes a pair of suction openings  422  located on opposite sides of the distal end  409  of the cutting head  404 . One method of forming the suction openings  422  is to cut an elongated groove or grooved area  419  into the wall  411 , and specifically into portions of the respective wall segments  418 , of the cutting head  404 . These grooved areas  419  are formed on opposite sides of the cutting head  404 , and form the grooves or flutes of the cutting head  404 . The grooved areas  419  extend generally linearly along the cutting head  404  in the proximal to distal direction, and each grooved area  419  is located between the respective cutting edges  413 . This cutting process results in elongated or generally elliptically-shaped suction openings  422  located at the bottom of each grooved area  419 . In the illustrated embodiment, each suction opening  422  is disposed closely adjacent a respective cutting edge  413 . Further, as shown in  FIGS. 27 and 30 , the wall  411  has a thickness dimension T 1 , measured in a direction transverse to the axis  408 , at an area circumferentially between the suction openings  422  which is substantially greater than a thickness dimension T 2  of the wall  411  adjacent the suction openings  422 . This increased wall thickness T 1  provides the cutting head  404  with increased structural integrity. 
     It will be appreciated that the cutting head  404  may alternatively be provided with a plurality of suction openings  422  oriented in a longitudinally or axially spaced-apart manner with one another along the cutting head  404  on one or multiple sides thereof between two circumferentially adjacent cutting edges  413 , as opposed to a single suction opening  422  located on each side of the cutting head  404  as shown in  FIGS. 23-29 . That is, the cutting head can have substantially straight cutting edges as shown in  FIGS. 23-29 , but instead include a row of suction openings as shown in the embodiment of  FIGS. 1-9  on one or multiple sides thereof. 
     Each suction opening  422  extends completely through the wall  411  so as to communicate with the hollow interior  405  of the cutting head  404 , and opens both sidewardly and distally through the cutting head  404 . In the illustrated embodiment, the suction openings  422  lie directly in front of the cutting face  416  of the respective cutting edge  413  when considered in the context of the rotational direction of the cutting head  404  during use. This orientation of the suction openings  422  provides a direct entry port into the interior  405  of the cutting head  404  so that debris generated by the cutting action of the cutting edges  413  is immediately evacuated from the surgical site via the suction openings  422 . 
     Although particular preferred embodiments of the invention are disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.