Abstract:
A surgical tool system with a handpiece that is directed towards a surgical site. Irrigating fluid from a pump is pumped through a conduit integral with the handpiece for application to the surgical site. A valve regulates fluid flow through the handpiece conduit. A valve state sensor monitors the position of the valve and generates a sensor signal representative of valve state. The sensor signal is applied to a control unit that regulates actuation of the pump. The control unit regulates the actuation of the pump based on the valve state as indicated by the sensor signal. The pump may be a variable flow rate pump; the control unit increases pump output when the sensor signal indicates the valve is in fully opened position. The handpiece may include a suction fitting; the valve can selectively connect the conduit to the pump or the suction fitting.

Description:
[0001]    This application is a divisional of U.S. patent application Ser. No. 09/302,148, filed Apr. 29, 1999, now U.S. Pat. No. ______, the contents of which are incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This application relates generally to powered surgical handpieces such as those employed in endoscopic surgery. More particularly, this invention is directed to a powered surgical handpiece that includes an irrigator for applying fluid to a surgical site, a suction conduit for drawing fluid from the site, a means for clearing the suction conduit and a motor for actuating a complementary cutting accessory.  
         BACKGROUND OF THE INVENTION  
         [0003]    The powered handpiece has evolved into an important tool for performing surgical procedures. A typical powered handpiece includes a housing that contains an electrically driven motor. A coupling assembly is attached to one end of the handpiece. The coupling assembly is used to releasably secure a cutting accessory to the motor so that the motor, when energized, actuates the cutting attachment. The development of powered surgical handpieces and their complementary cutting accessories has made it possible to cut, shape and remove both hard and soft body tissue at faster rates and with a higher degree of accuracy than was possible with the manually powered tools that preceded them.  
           [0004]    When a cutting attachment is actuated, the cutting action causes loose tissue and other debris to develop at the surgical site. This material is removed by applying an irrigation fluid to the site and also drawing a suction from the site. The irrigation fluid serves as a transport media for carrying the debris; the suction draws away the fluid and the entrained debris. In order to perform this irrigation and suction, some cutting attachments are provided with conduits through which fluid is applied to and drawn from the surgical site. For example, cutting attachments designed to perform endoscopic surgery or sinus surgery often include a static outer sleeve in which a rotating tube is fitted. The head of the rotating tube is provided with some type of cutting surface or cutting member. Each of these attachments is further shaped so that irrigation fluid can flow to the surgical site through the annular channel between the rotating tube and the static sleeve. The inner rotating tube is further provided with an opening adjacent the head through which a suction is drawn from the surgical site. Thus, the inner tube serves as the conduit through which the irrigation fluid and debris are removed from the surgical site.  
           [0005]    A powered handpiece intended for use with the above cutting attachments is designed with complementary features that facilitate the drawing of the suction away from the surgical site. Specifically, this type of handpiece is provided with a suction bore to which a suction pump is applied. The coupling assembly allows fluid flow from the inside of the rotating tube to the suction bore. Moreover, the handpiece is provided with a valve for regulating fluid flow through the suction valve. Thus, a surgeon using this type of handpiece can, with one hand, both manipulate the cutting accessory and regulate the rate at which fluid is drawn from the surgical site.  
           [0006]    While current handpieces have provided useful for both driving cutting attachments and drawing a suction, there are some disadvantages associated with their use. In particular, current handpieces and their complementary cutting attachments are designed so that irrigation fluid is introduced into the annular channel through a supply line that is separate from the handpiece. While this supply line may be attached to a handpiece, it has a free end that is typically located forward of the handpiece coupling assembly. The free end of this line has to be manually fitted to an inlet luer integral with the static sleeve. When, during a surgical procedure, the doctor wants to switch cutting attachments, this line must first be removed from the cutting attachment being separated from the handpiece. Then, after the new cutting attachment is installed, the supply line must be manually fitted to the new attachment. The time it takes to perform these steps adds to the overall time it takes to perform the surgical procedure.  
           [0007]    Moreover, in these surgical handpieces, the motor is in close physical proximity to the path through which the suction fluid flows through the handpiece. Accordingly, these handpieces must be constructed to include sufficient seals that prevent liquid flow into the components forming the motor. However, over time, and owing to the presence of the moving parts against which these seals press, these seals can wear out. Consequently, it is not uncommon for fluid to enter the motor and cause the components forming the motor to corrode and/or malfunction. Once the integrity of these seals diminishes, this corrosion and motor component wear can occur at a relatively fast rate because the fluid drawn through the handpiece suction is saline.  
           [0008]    Also, occasionally, debris can clog the cutting accessory rotating tube through which the suction is drawn from the surgical site. This clogging is especially prone to occur in cutting accessories designed for performing sinus surgery. This is because the diameter of the bore through which this suction flow travels is relatively narrow. Presently, there are two ways a surgeon can try to remove this type of clog in order to reestablish suction at the surgical site. One method involves introducing a large quantity of irrigation fluid into the surgical site. The surgeon takes this action by momentarily running the irrigation pump used to supply fluid at a high speed/high flow flush setting. The introduction of this large quantity of water causes a large fluid pressure head to develop in the rotating tube upstream of the clog. If the conditions are right, the pressure head of this fluid forces the clog-causing debris to flow downstream out of the rotating tube. One problem with this clog removal technique is that the switches for regulating the irrigation pump are typically located off the handpiece. In order for the surgeon to be able to control the pump, he/she must actuate a separate foot or hand switch or instruct an assistant to perform this operation. In each of these situations, the surgeon may have to significantly divert his/her attention from the actual surgical procedure being performed. Still another problem with this method of clog removal is that, often, it simply does not work. Then, the surgeon is left with a situation in which excess fluid has been introduced into the patient.  
           [0009]    The second method of clog removal is more mechanical. This method involves running a rigid wire down the rotating tube in order to force the clog out of the tube. When a surgeon has to take this action, he/she must first withdraw the cutting attachment from the surgical site. Then, once the clog is removed, the cutting attachment must be repositioned so that the surgical procedure can be completed. The need to perform these tasks adds to the overall time it takes to perform the surgical procedure.  
         SUMMARY OF THE INVENTION  
         [0010]    This invention relates to an improved powered surgical handpiece and a cutting accessory for use with the handpiece. This invention includes a motor that has a rotor integral with the cutting accessory and complementary windings that are integral with the handpiece. The handpiece has a coupling assembly for holding the cutting attachment to the handpiece that has a conduit through which irrigation fluid is introduced into the attachment for application to the surgical site. The handpiece of this invention also has a valve for regulating fluid flow through the conduit through which a suction is normally drawn. Depending on the setting of this valve, a suction can be drawn through the cutting attachment, the suction shut off or irrigation fluid can be introduced into the suction conduit in order to flush out any debris lodged in the conduit. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The invention is pointed out with particularity in the claims. The above and further features of this invention may be better understood by reference to the following description taken in conjunction with the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is a perspective view of a powered surgical handpiece of this invention and a complementary cutting accessory attached to the handpiece;  
         [0013]    [0013]FIG. 2 is a cross sectional view of the distal end of the handpiece as well as of the portion of the cutting accessory seated in the handpiece;  
         [0014]    [0014]FIG. 2A is a detailed cross sectional view of the motor depicted in FIG. 2;  
         [0015]    [0015]FIG. 3 is a perspective view of the cutting accessory;  
         [0016]    [0016]FIG. 4 is a cross sectional view of the cutting accessory;  
         [0017]    [0017]FIG. 5 is a enlarged view of the distal end of the handpiece;  
         [0018]    [0018]FIG. 6 is a section view of a lateral slice of the handpiece taken along line  6 - 6  of FIG. 5;  
         [0019]    [0019]FIG. 7 is a cross sectional view of the inside of the handpiece;  
         [0020]    [0020]FIG. 8 is a perspective cutaway view of the handpiece;  
         [0021]    [0021]FIG. 9 is a section view of a lateral slice of the handpiece taken along line  9 - 9  of FIG. 7;  
         [0022]    [0022]FIG. 10 is a cross sectional view of the inside of the handpiece depicting the fluid conduits in the end cap that lead to and from the valve member;  
         [0023]    [0023]FIG. 11 is a perspective view depicting the relationship of the slide lever, the slide rod and valve member;  
         [0024]    [0024]FIG. 12 is a plan view of the relative position of the valve member and the associated conduits with the valve member is in the suction full on state;  
         [0025]    [0025]FIG. 13 is a plan view of the relative position of the valve member and the associated conduits when the valve member is in the suction partial on state;  
         [0026]    [0026]FIG. 14 is a plan view of the relative position of the valve member and the associated conduits when the valve member is in the suction-and-purge off state; FIG. 15 is a plan view of the relative position of the valve member and the associated conduits when the valve member is in the purge flow on state; and  
         [0027]    [0027]FIG. 16 is a block diagram of how an alternative cutting accessory is coupled to an alternative shaft of an alternative handpiece of this invention. 
     
    
     DETAILED DESCRIPTION  
       [0028]    [0028]FIGS. 1 and 2 depict a powered surgical handpiece  20  of this invention along with a cutting accessory  22  that is driven by the handpiece. The handpiece  20  has a generally cylindrical sleeve-like shell  24  that serves as the housing for the other components of the handpiece. The proximal end of the cutting accessory  22  is also seated in shell  24 . (Hereinafter “front”, “forward” and “distal” shall be understood to means portions of the handpiece  20  or cutting accessory  22  located towards the end of the cutting accessory applied to the surgical site. “Rear”, “rearward” and “proximal” shall be understood to be portions of the handpiece  20  and cutting accessory  22  located away from the end of the cutting accessory applied to the surgical site.) Collectively, the handpiece  20  and cutting accessory  22  are provided with components that form a motor  26  for actuating the cutting accessory  22 . The energization signals that are applied to the motor  26  are generated by a control console  28  and applied to the motor over a power cable  30 . One such control console  28  that can be employed to generate the energization signals is the TPS™ control console manufactured by the Applicant&#39;s Assignee. A switch assembly, such as a foot switch, not illustrated and not part of this invention, is used for regulating the actuation of the handpiece motor  26 . This switch assembly is connected to the control console  28 . Based on the signals generated by the switch assembly, the control console  28  applies the energization signals to the handpiece motor  26 .  
         [0029]    The handpiece  20  includes a coupling assembly  32  that releasably holds the cutting accessory  22  to the handpiece. An irrigation pump  34  applies an irrigation fluid to a supply line  36  that is fitted in shell  24 . The irrigation fluid is introduced into the cutting accessory  22  for application to the surgical site through the coupling assembly  32 . In the preferred version of the invention, irrigation pump  34  is a module built into and regulated by the control console  28 .  
         [0030]    A suction is drawn from the surgical site through the cutting accessory  22  and handpiece  20  by a suction pump  38 . A manually-set slide lever  40  extends around the outside of the shell  24  and is located immediately rearward of the coupling assembly  32 . Slide lever  40  sets the position of a valve member  42  internal to the handpiece  20  which regulates fluid flow through a suction conduit integral with the cutting accessory  22 . Depending on the position of the valve member  42 , suction pump  38  may draw a suction through the conduit, the suction flow may be attenuated, the suction flow may be completely shut off or the flow from irrigation pump  34  may be directed through the cutting accessory suction conduit.  
         [0031]    The cutting accessory  22 , now described by reference to FIGS. 3 and 4, includes a static hub  46  formed of plastic such as a polycarbonate plastic. Static hub  46  has a proximal end  48  with a circular cross sectional profile. The static hub  46  has a distal end  49  formed integrally with the proximal end  48 , that has a cross sectional profile that is at least partially asymmetric relative to the longitudinal axis of the hub. In the depicted version of the invention, this static hub distal end  49  is formed so that one surface thereof has a round profile and the opposed surface is shaped to define an alignment key  50 . The alignment key  50  projects beyond the circle defined by the proximal end  48  of the hub  46  and is shaped to have a flat outer surface. A through bore  47  extends axially through static hub  46  from the proximal end  48  to the distal end  49 .  
         [0032]    The static hub  46  is further formed to have a rectangular notch  52  that extends inwardly from the flat surface of the alignment key  50 . As discussed hereinafter, a complementary component of the handpiece coupling assembly  32  seats in notch  52  to hold the cutting accessory  22  to the handpiece  20 . A fluid inlet bore  54  extends perpendicularly relative to the longitudinal axis of accessory  22  from the alignment key  50  to through bore  47 . Fluid inlet bore  54  serves as the conduit through which irrigation fluid is introduced into the cutting accessory  22  from supply line  36 . In the depicted version of the invention, an irrigation seal  56  formed from a soft rubber such as is sold under the trademark VITON by the duPont Company of Delaware is seated around the open end of fluid inlet bore  54 . Irrigation seal  56  is seated in a cutaway space  58  integral with notch  52 . Seal  56  is shaped so that the outer surface thereof is flush with the outer flat surface of the alignment key  50 .  
         [0033]    A rigid, outer tube  60  formed of stainless steel is firmly connected to the static hub  46  and extends forward from the distal end of the through bore  47 . In the depicted version of the invention, the outer tube  60  is shown as having a closed distal end though that not may always be the case. (The distal end of the outer tube  60  is the end of the tube applied to the surgical site.) Outer tube  60  is formed to have a fluid inlet opening  62  that is concentric with and has the same radius as fluid inlet bore  54 .  
         [0034]    Cutting accessory  22  also has a rotating hub  63  that is located rearward of static hub  46 . Rotating hub  63  is formed from a plastic such as polycarbonate plastic. The rotating hub  63  has a main body  66  that is located immediately rearward of proximal end  48  of static hub  46 . In the depicted version of the invention, the cross sectional profile of rotating hub  63  is identical to that of the adjacent static hub proximal end  48 .  
         [0035]    The rotating hub  63  is formed to have a neck  68  and a head  70  that extend forward from the main body  66  into the static hub proximal end  48 . More specifically, neck  68  extends forward from body  66  and has a constant diameter cross section profile less than the diameter of the main body. Head  70  is shaped to have a tapered profile such that the portion of the head immediately adjacent neck  68  has a diameter greater than that of the neck and the most distal end of the head has a cross-section diameter approximately equal to the diameter of the neck. The neck  68  and head  70  are seated in complementary shaped bores  72  and  74 , respectively, formed in the static hub proximal end  48 . Bores  72  and  74 , it will be observed, surround and are contiguous with through bore  47 . More specifically, the hubs  46  and hub  63  are formed so that there is an interstitial gap between the outer surfaces of neck  68  and head  70  and the inner surfaces of the static hub  46  that define bores  72  and  74 . In preferred versions of the invention, this annular gap, not identified, is between 20 and 25 mils (0.5 and 0.7 mm). This gap reduces friction between the interface of the neck  68  and head  70  and the static hub  46 .  
         [0036]    Rotating hub  63  is further formed with an axially extending through bore  76  that is concentric with the static hub through bore  47 . An outwardly tapered counterbore  78  is formed with through bore  76  at the proximal end of the rotating hub  63 .  
         [0037]    A rotating inner tube  79  is securely mounted to the inner wall that defines through bore  76  in order to turn in unison with rotating hub  63 . Inner tube  79  extends forward from the distal end of rotating hub  63  into the center of outer tube  60 . The distal end of inner tube  79  is formed to serve as a cutting head. In the depicted versions of the invention, the distal end of the inner tube  79  is open and has sharp edges so that this end of the tube functions as a planar. It should, of course, be recognized that different heads may be attached to the distal end of the inner tube so that the cutting accessory  22  may serve as a burr, a shaver, a resector or other cutting device.  
         [0038]    It should be realized that when the cutting accessory  22  is a cutter or a shaver, the distal end of the static outer tube  60  is closed. In these cutting accessories  22 , the distal end of the inner tube  79  is dimensioned to abut against the inner wall of the closed distal end of the outer tube  60 . Thus, the inner tube  79  holds the main body  66  and head of the rotating hub  63  away from, respectively, the distal end of the static hub  46  and the inner wall of the static hub that defines bore  74 . This holding off of the rotating hub  63  from the adjacent surfaces of the static hub  46  as well as the fact that neck  68  is spaced inwardly from the walls defining bore  72  serves to substantially eliminate frictional between the hubs.  
         [0039]    Outer and inner tubes  60  and  79 , respectively, are further dimensioned so that there is a small annular channel  81  between the outer wall of the inner tube  79  and the adjacent inner wall of the outer tube  60 . Annular channel  81  serves as the conduit through which irrigation fluid flows from the fluid inlet bore  54  and the fluid inlet opening  62  to the surgical site. The hollow center of inner tube  79  serves as a conduit  82  through which a suction is applied to the surgical site for drawing fluid and debris away from the site.  
         [0040]    The handpiece  20  is now described in detail with an initial discussion of the construction of the coupling assembly  32 , best seen by reference to FIGS. 2, 5 and  6 . The front end of the handpiece  20  is provided with a solid coupling body  86  formed of PEEK plastic that is seated in the front end of shell  24 . More specifically, in the depicted version of the invention, the forward end of shell  24 , is shaped to subtend an arc of approximately 200 to 260°. Immediately rearward of this section of the shell  24 , the shell is shaped to have a forward-directed front plate  83 .  
         [0041]    The section of coupling body  86  seated in shell  24  thus has an exposed outer surface  85 . The coupling body  86  is further shaped to have a head section  87  that extends forward of shell  24 . Head section  87  has a cross-sectional profile that is approximately equal to that of the adjacent end of the shell  24  from which the head extends. Coupling body  86  has an axially extending bore  88  dimensioned to receive static hub  46 . The coupling body  86  is formed so that bore  88  has a distal opening  90  with a cross-sectional profile identical to that of the static hub distal end  49 , including the alignment key  50 . This configuration insures that the static hub  46  seats in coupling body  86  in a specific orientation for purposes to be explained below.  
         [0042]    The coupling assembly  32  also includes an oval-shaped coupler arm  92 . The arm  92  is slidably mounted to the outside of coupler body  86  so as to move perpendicularly relative to the longitudinal axis of the handpiece  20 . Coupler arm  92  has two parallel, spaced apart links  94  each of which is seated in a separate slot  96  formed by an interstitial space between the distal end of the shell  24  and the proximal end of the coupler body head section  87 . Links  94  are connected together at one end by a locking member  98 . The locking member  98  is positioned adjacent an opening  102  in the exposed surface  85  of the coupler body  86  rearward of head section  87 . Opening  102  extends into the distal section  90  of bore  88 . The locking member  98  is formed to have a tab  104  that extends through opening  102  into bore  88 . Tab  104  is the component of the coupling assembly  32  that seats in notch  52  to hold the cutting accessory  22  to the handpiece  20 . The tab  104  is formed with a forward facing surface  105  that is angled rearwardly to facilitate the fitting of the cutting accessory  22  to the handpiece  20 .  
         [0043]    Irrigation fluid is introduced into the cutting accessory  22  through the coupler arm  92 . Specifically, the distal end of the supply line, distal supply line  36   a  in the drawings, is fitted into a rearward facing bore  106  formed in locking member  98 . Locking member  98  has a cylindrical outlet fitting  108  that is in fluid communication with bore  106  and is directed inwardly towards the longitudinal axis of the handpiece  20 . Outlet fitting  108 , which is located rearward of tab  104 , is positioned so that when the tab  104  seats in the cutting accessory notch  52 , the fitting  108  seats in the opening integral with irrigation seal  56 . Thus, when the cutting accessory  22  is mounted to the handpiece  20 , fluid flows from the supply lines  36  and  36   a , through bore  106  and fitting  108 , into accessory inlet bore  54 , inlet opening  62  and channel  81  to the surgical site.  
         [0044]    The ends of links  94  distal from locking member  98  are connected together by a semi-circular web  110 . Two springs  112  bias coupler arm  92  so that tab  104  is normally urged into bore  88 . The springs  112 , which are parallel to each other, are connected at one end to separate posts  114  fitted in coupler body head section  87 . The opposed end of each spring  112  is connected to a small set screw  116  that extends forward from an adjacent one of the links  94 . The coupler body head section  87  is further formed to have opposed grooves  118  in which each spring  112  is seated. Since the springs  112  are seated in grooves  118 , the likelihood of an individual inadvertently disturbing a spring or finger or an article of clothing becoming caught in one of the springs is substantially eliminated.  
         [0045]    The motor  26  seen best in FIGS. 2 and 2A, includes a stator  122  that is mounted in the shell  24  and a set of magnets  124  that are disposed in the cutting accessory rotating hub  63  as seen in FIGS. 2, 4 and  7 . In one preferred version of the invention, the motor is a four-pole, three-phase brushless, sensorless DC motor. More specifically, the stator  122  includes a set of three windings  121  that are wound around a cage  123 . Electrically, the windings are 120° apart from each other. It should be understood that physically, the windings may overlap. The stator  122  is encased in an insulating shell  125  that is formed from non-conductive material such as PEEK plastic. Shell  125  is shaped so as to define an axially extending center space  126  in which the cutting accessory rotating hub  63  is seated. More particularly, the shell  125  is dimensioned so that there is a small air gap between the inner wall of the shell defining space  126  and the outer wall of the rotating hub  63 . This air gap is approximately 20 mils, (0.5 mm). This air gap essentially eliminates the rotating friction between the rotating hub  63  and the shell  125 .  
         [0046]    The rear end of stator shell  125  is seated on an annular step  128  formed integrally with handpiece shell  24 . Step  128  extends inwardly from the inner wall of handpiece shell  24  towards the longitudinal center of the handpiece  20 .  
         [0047]    Since motor  26  is a four-pole motor, four magnets  124  are mounted in the rotating hub. The magnets  124  are elongated members that are spaced equiangularly around the longitudinal axis of the cutting accessory  22 . The magnets are formed so that their N/S polar orientation is located along an axis perpendicular to the longitudinal axis of the cutting accessory  22 . Thus, for a first one of the magnets  124 , the North pole is oriented towards the center of the rotating hub. The magnets  124  adjacent the first magnet are arranged so that their South poles are oriented towards the center of the rotating hub.  
         [0048]    The magnets  124  may have a cross sectional profile that is either curved or squared. Alternatively, the magnets may even have arcuate cross sectional profile. In these versions of the magnets  124 , the outer face of each magnet may have a convex profile having a first radius while the inner face of the magnet has a concave profile with a radius less than that of the first radius. The magnets  124  may be made out of any appropriate material such as samarium cobalt.  
         [0049]    A plunger  134  is seated in the rearward portion of stator  122 . The plunger  134  is formed from stainless steel. The plunger  134  has a cylindrical stem  136 . Stem  136  is mounted in a plunger bearing assembly  138 . The plunger bearing assembly  138  is seated in the front end of the valve member  42  as will be described hereinafter. Plunger  134  is further formed with a head  140  that is formed integrally with and has a larger cross sectional diameter than the stem  136 . In the depicted version of the invention, plunger head  140  is dimensioned so that it comes close to, but does not abut the adjacent inner wall of the stator  122 . The plunger head  140  has a center section  142  that extends forward from the outer perimeter of the head. The center section  142  of the plunger head  140  seats in counterbore  78  formed in the proximal end of rotating hub  63 .  
         [0050]    A bore  146  extends axially through plunger  134  from the proximal end of the plunger to the distal end. Bore  146  serves as a conduit through which fluid flows between valve member  42  and rotating hub bore  76 . In the depicted version of the invention, the plunger head  140  has a counterbore  148 , concentric with bore  146 , that has the same diameter as the rotating hub bore  76 .  
         [0051]    A coil spring  150  is disposed around plunger stem  136  and extends between plunger bearing  138  and the rearward facing surface of plunger head  140 . Spring  150  provides the biasing force that urges the plunger  134  forward so that the plunger imparts a like force to cutting accessory  22 . A retaining ring  152  fitted in a groove extending around the end of stem  136  seated within the valve member  42  (groove not identified). Retaining ring  152  abuts against the rearward facing surface of plunger bearing assembly  138  to prevent the plunger  134  from separating from the bearing assembly  138 .  
         [0052]    An explanation of how fluid is selectively introduced into and drawn from conduit  82  of cutting accessory  22  through the handpiece  20  of this invention is now set forth with initial reference to FIGS.  7 - 9 . As seen in these drawings, a solid, cylindrical end cap  156  formed of PEEK plastic is seated in the proximal end of shell  24 . End cap  156  is formed with a suction bore  158  that extends laterally through the end cap. It will be observed that suction bore  158  is laterally offset from the longitudinal axis of the end cap  156 . Suction bore  158  is formed to have a threaded counterbore  160  which is located at the proximal end of the end cap  156 . A luer fitting  162  is seated in suction bore counterbore  160 . The luer fitting  162  serves as a means to connect a suction line  164  between the suction bore  158  and suction pump  38 . The opposed end of suction bore  158  defines an opening  165  in the distal end face of end cap  156 .  
         [0053]    End cap  156  is also formed to have a supplemental conduit  166 . The supplemental conduit  166  serves as the conduit in which the electrical conductors integral with the handpiece  20  are seated (conductors not illustrated). The supplemental conduit  166  extends forward from the proximal end of the end cap  156 . In the depicted version of the invention, end cap  156  is formed so that supplemental conduit  166  is laterally offset from the longitudinal axis of the handpiece  20 . Supplemental conduit  166  has two sections. There is a proximal section  168  in which the conduit is essentially parallel to the suction  158 . There is also a distal section  170  that is contiguous with and extends forward from proximal section  168 . Distal section  170  angles away from proximal section  168  and opens in the side of the end cap  156  at a point rearward of the distal end of the end cap. The conductors extend out of the end of the opening of supplemental conduit distal section  170  and seat in a groove  171  formed on the inner wall of shell  24   
         [0054]    (FIG. 9). The conductors extend from the shell  24  to the stator  122  to provide energization signals to motor  26 . A tube-shaped ferule  169  extends rearwardly from the open proximal end of the supplemental conduit  166 . Ferule  169  protects the end of the cable  30  that extends into the conduit  166 .  
         [0055]    The irrigation fluid supply line  36  is fitted in a groove  172  that extends longitudinally along the outside of shell  24  seen best by reference to FIGS. 2, 5 and  10 . Supply line  36  terminates at one end of a T-connector  174  mounted to the end cap. Distal supply line  36   a  extends from the opposed end of T-connector  174  into the bore  106  associated with coupler arm  92 . More specifically, groove  172  extends forward a short distance from T-connector  174  and distal supply line  36   a  is seated in the groove. Distal supply line  36   a  extends through groove  172  and out through an opening  175  in the shell front plate  83 . The forward end of the distal supply line  36   a  is the end of the line fitted to coupling arm bore  106 .  
         [0056]    Focusing on FIG. 10, it can be seen that the center stem of T-connector  174  is mounted in an L-shaped irrigation bore  176  formed in the distal end of end cap  156 . Bore  176  has an opening  178  in the distal end face of the end cap  156 .  
         [0057]    Valve member  42 , now described by reference to FIGS. 7 and 11, is shaped to have a generally cylindrical shape. The valve member  42  has a circular, disc-like base  180  that abuts the distal end face of end cap  156 . The space forward of end cap  156  is the valve chamber  179  of handpiece  20 . Valve member base  180  has a tear-dropped shaped opening  182  that, depending on the position of the valve member  42 , is selectively positioned to be in registration with suction bore opening  165  or irrigation bore opening  178 . The valve member  42  is further formed to have tube-like body  184  that extends forward from the distal end of base  180 . The body  184  is the portion of the valve member  42  to which plunger bearing assembly  138  is mated and in which the plunger stem  136  extends. More specifically, the inner wall of valve member body  184  is formed to define an annular step  186  in which the plunger bearing assembly  138  is seated.  
         [0058]    The setting of valve member  42  is controlled by slide lever  40 . The slide lever  40  has a curved section  190  that fits around the portion of shell  24  that surrounds coupler body  86 . Slide lever  40  also has a flat section  192  integral with the curved section  190  that is located against the exposed surface  85  of the coupler body below coupler arm  92 . A slide rod  194  extends rearwardly from slide lever flat section  192 . Slide rod  194  is seated in a longitudinally extending groove  196  formed on the inside wall of shell  24 . In order to ensure that the slide rod seats in groove  196 , the rod is formed to have a semi-circular cross sectional profile.  
         [0059]    Slide rod  194  is provided with a pin  198  (shown in phantom) that extends inwardly towards the longitudinal axis of the handpiece  20 . Pin  198  seats in a helical groove  202  (shown in phantom) formed in the outer surface of valve member body  184 . Thus, the forward/rearward displacement of slide lever  40  and slide rod  194  controls the rotational position of valve member  42 .  
         [0060]    An extension rod  204 , seen in FIGS. 8 and 9, is attached to the proximal end of slide rod  194  to move with the slide rod. Extension rod  204  has a generally circular cross sectional profile. The outer half of extension rod  204  seats in shell groove  196 . The inner half of extension rod  204  seats in a groove  206  formed along the outer wall of end cap  156 . A small magnet  208  is mounted in an opening in extension rod located adjacent the distal end of the rod  204  (opening not identified).  
         [0061]    Extension rod  204  is shaped to have a reduced diameter pin  210  that extends rearwardly from the proximal end of the rod  204 . Pin  210  seats in a forward-facing bore  220  (shown in phantom) formed in the proximal end of end cap  156 . A spring  212  extends around pin  210 . Spring  212  provides a biasing force that push extension rod  204 , slide rod  194  and slide valve  40  forward. Thus, slide valve  40  is normally positioned to be located immediately rearward of locking member  98 .  
         [0062]    A reed switch  216 , or other sensor, is seated in the end cap  156  to monitor the displacement of magnet  208 . In the depicted version of the invention, reed switch  216  is mounted in a branch channel  218  that extends laterally away from the proximal section  168  of supplemental conduit  166 . The signal across the reed switch is monitored by a circuit internal to control console  28 . The electrical conductors (not illustrated) that extend to reed switch  216  are fitted in conduit  166 . Also, in the depicted version of the invention, branch channel extends to groove  206  though this need not always be the case. The open/closed state of reed switch  216  is monitored by a controller internal to irrigation pump  34 .  
         [0063]    A tube-like handgrip  220  formed of rubber surrounds shell  24 . The handgrip  220  surrounds the portion of the shell that extends rearward from plate  83 .  
         [0064]    The handpiece  20  of this invention is readied for use by the fitting of the cutting accessory  22  to the handpiece. This is performed by inserting the accessory hubs  46  and  63  into the open end of handpiece bore  88 . When the static hub alignment key  50  seats in the bore distal opening  90 , the flat face of the key abuts against the angled forward facing surface  105  of tab  104 . Owing to the angle of surface  105 , this action causes the tab  104  to automatically retract away from bore  88  so that the cutting accessory  22  can continue to be fitted in place. Once notch  52  of static hub  46  comes in registration with tab  104 , springs  112  urge locking member  98  towards the center axis of the handpiece so that the tab seats in the notch. The seating of the tab  104  in notch  52  locks the cutting accessory  22  in place.  
         [0065]    Simultaneously with the seating of tab  104  in notch  52 , outlet fitting  108  comes into registration with accessory inlet bore  54 . Thus, the locking of the cutting accessory  22  to the handpiece  20  of this invention results in the automatic establishment of a path through which irrigation fluid can flow through supply lines  36  and  36   a  into the annular channel  81  of cutting accessory  22 . Thus, once the coupling accessory  22  is fitted to the handpiece  20  additional time need not be spent establishing this fluid connection.  
         [0066]    It should also be understood that when irrigation fluid is introduced into the inlet bore  54 , the fluid does not flow rearward beyond the interface of the static hub  46  and rotating hub  63 . This is because the pressure head of the fluid is not sufficient to force the fluid between the narrow gap between the hubs  46  and  63 .  
         [0067]    When it is necessary to remove the cutting accessory  22  from the handpiece  20 , all one needs to do is manually urge coupler arm web  110  inwardly towards shell  24 . This action causes tab  104  to retract away from cutting accessory notch  52 . Simultaneously with the retraction of tab  104 , outlet fitting  108  retracts away from bore  54 . Once the tab  104  is moved away from notch  52 , cutting accessory  22  can be manually removed from bore  88 . The removal of the cutting accessory  22  is facilitated by the fact that, once the tab  104  is so retracted, the force of the plunger spring  150  is fully released. Thus, the spring  150  pushes the plunger  136  forward so the plunger causes a like displacement of the cutting accessory  22  out of the forward end of the handpiece  20 .  
         [0068]    The cutting accessory  22  is actuated by selectively applying energization currents to the windings integral with the stator  122 . These currents cause magnetic fields to develop which attract the magnets  124  internal to rotation hub  63 . The attraction of the magnets  124  to the windings causes rotation of hub  63  as well as inner tube  79  integrally attached thereto. Plunger  134 , which is pressed against rotating hub  63 , rotates with the hub. An advantage of this arrangement is that in this construction only the single bearing assembly  138  is required to insure the free rotation of rotor that is integral with the motor. Moreover, since the windings and magnets  124  are contained in their own sealed housings, and there are no bearings, it is not necessary to provide a separate sealed housing for the motor  26 . Two advantages of this construction are that it eliminates both the cost and weight of having to provide a sealed housing. Still another benefit of this feature of the invention is that the motor  26  of this handpiece  20  does not have any metal components that are exposed to fluid in the event a seal wears or breaks. Thus, there is little likelihood that the motor of this invention will malfunction due to corrosion-induced component failure.  
         [0069]    The handpiece  20  of this invention is further configured to regulate whether or not a suction is drawn through or irrigation fluid is applied to conduit  82  integral with the cutting accessory inner tube  79 . During normal operation of the handpiece  20 , valve member  42  has the rotational orientation depicted in FIG. 12. Here, the valve member  42  is positioned so that the largest diameter section of base opening  182  is in registration with opening  165  integral with suction bore  158 . Thus, when the valve member  42  is in this position, the maximum possible suction is drawn from the surgical site through inner tube conduit  82 , rotating hub bore  76 , plunger bore  146  and the suction bore by suction pump  38 . Further, when the valve member  42  is in this position, base  180  covers and closes irrigation bore opening  178 . The sealing closed of opening  178  prevents irrigation fluid from being introduced into the center of the valve member when the suction is being drawn.  
         [0070]    A surgeon attenuates the suction drawn at the surgical site by moving slide lever  40  rearward towards handgrip  220 . This motion causes a like displacement of slide rod  194 . The displacement of slide rod  194  causes valve member  42  to rotate first to the position depicted in FIG. 13. When the valve member  42  is in this position, the narrow diameter section of valve member base opening  182  is in registration with suction bore opening  165 . Thus, at this time, a reduced volume suction flow is drawn by the pump  38  from the surgical site through the inner tube conduit  82  and the valve member  42 .  
         [0071]    The surgeon may totally turn off the suction drawn at the surgical site by simply moving the slide lever  40  rearwardly. The like movement this induces in the slide rod  194  and pin  198  causes the pin to rotate the valve member  42  into the position shown in FIG. 14. When in this state, the valve member  42  covers the both suction bore opening  165  and the irrigation bore opening  178 . Thus, at this time, there is no fluid flow in any direction through the inner tube conduit  82  to or from the surgical site.  
         [0072]    The handpiece  20  of this invention is configured to direct a purge flow through the inner tube conduit  82  in the event the conduit becomes clogged. Specifically, if this event occurs, or for another reason the surgeon wants a very large fluid flow to be introduced into the surgical site, the surgeon presses the slide lever  40  so that the lever is in its most rearward position. This displacement of the slide lever  40  and the associated slide rod  194  results in two effects. First, this displacement causes the valve member  42  to rotate into the position depicted in FIG. 15 in which the large diameter portion of base opening  182  comes into registration with irrigation bore opening  178 . Secondly, the magnet  208  that moves with the slide rod  194  moves very close to reed switch  216 . This motion causes the reed switch  216  to close so that the signal produced by the switch changes state. This signal change is interpreted by control console  28  as an instruction to boost the rate at which fluid is discharged from the irrigation pump  34 . Thus, the moving of the slide valve  40  to the purge position resets the valve member  42  so that irrigation fluid is directed through inner tube conduit  82  and sets the irrigation pump  34  to force a relatively high pressure flow through this conduit. Collectively, this means that when the handpiece  20  is in the purge state, a relatively high pressure stream of fluid is directed through the inner tube conduit  82  towards the surgical site. In many situations, this high pressure fluid stream has enough force to dislodge the debris that are blocking normal suction flow through the inner tube  79 .  
         [0073]    Thus, the handpiece  20  of this invention provides a means for automatically establishing and breaking an irrigation connection to the cutting accessory  22 , has relatively few moving parts and has means to provide a purge flow to the conduit integral with the cutting accessory through which the suction flow is normally drawn.  
         [0074]    It should be understood that the foregoing description is directed to one specific embodiment of the invention. It will be apparent, however, from the description that alternative constructions of the invention are possible. For example, not all versions of the invention may have an outlet fitting for providing a fluid communications path to the complementary cutting accessory. Similarly, other versions of the handpiece may not be constructed so that the rotating hub of the cutting accessory forms part of the motor or with a valve member that can be used to introduce a purge flow into the suction conduit integral with the cutting accessory.  
         [0075]    For example, it may be desirable to provide a handpiece and complementary cutting attachment of this invention with just the described motor  26 . These particular components would thus be designed as tools for conventional surgery in which the handpiece does not also provide irrigation fluid and/or draw suction from the site. Similarly, it may be desirable to provide a handpiece that simply functions as an conduit for supplying irrigation fluid to and/or drawing a suction from the surgical site that has the features of this invention. Specifically, it will be noted that the setting of valve  42  does not effect the always open fluid connection between supply lines  36  and  36   a . So when valve  42  is in the purge position, there is also fluid flow to the surgical site through annual channel  81 .  
         [0076]    Also, the components from which the handpiece and complementary cutting accessory are formed may have alternative constructions than what has been described. For example, it may be desirable to design the coupling assembly with multiple fingers that are positioned to move towards and away from the cutting accessory. In this version of the invention, the cutting accessory would be formed with recesses in which these fingers seat. The seating of the fingers in these recesses holds the cutting accessory to the handpiece. In these versions of the invention, the inlet fitting may be built into one of the fingers.  
         [0077]    It should also be recognized that some versions of the invention, the distal end of the outer tube  60  of the cutting accessory  22  may be open ended. This may be the case when the inner tube  79  is provided with a burr at its head end. In these versions of the invention, the tubes cannot be configured to hold the rotating hub  63  off away from the static hub  46 . Accordingly, in these versions of the invention, a flat ring formed of a low friction plastic such as the plastic sold under the trademark TEFLON by the duPont Company, may be fitted around the forward end of the rotating tube main body  66 . This ring serves as a bearing to minimize the friction between the rotating hub  63  and the static hub  46 .  
         [0078]    Alternatively, in some versions of the invention, the distal end of the inlet fitting  108  may seat in a counter bore formed integral with fluid inlet bore  54 . An advantage of this version of the invention is that it may eliminate the need to provide the irrigation seal  56  around bore  54 .  
         [0079]    Also, alternative versions of the motor may be provided. For example, while not optimal, the stator may be embedded in the rotating hub  63  and the magnets may be mounted to the handpiece. In these versions of the invention, some type of brushes integral with the handpiece would provide an electrical path between the control console  28  and the windings integral with the stator. Also, in some versions of the invention Hall sensors may be mounted in the handpiece  20 . These sensors would provide signals that indicate the rotational position of the rotating hub magnets  124 . The control console  28 , in turn, uses the signals representative of the position of these magnets as an input for regulating the energization of the stator windings.  
         [0080]    Moreover, it should likewise be understood that the rotating hub  63  may be provided with more or less magnets  124  than has been described. Typically, the rotating hub  63  will be provided with an even number of magnets. Similarly, stator  122  may have other constructions than what has been described.  
         [0081]    It should likewise be appreciated that there may be versions of the invention in which no part of the motor is built into the cutting accessory  22 . In these versions of the invention, as seen in FIG. 16, the rotating hub  63   a  may be provided with notches  212  or other means for engaging a complementary coupling member  214  that is integral with the shaft  216  of the motor  218  built into the handpiece  20   a . In these versions of the invention, once the rotating hub engages with the shaft, the hub, as well as inner tube  79  rotate in unison with the shaft.  
         [0082]    Also, it should be clear that the structure of the valve member may very from what has been described. Clearly, the valve member can rotate along an axis different than the longitudinal axis that runs through the handpiece  20 . It should be clear that, in these versions of the invention the conduits in the end cap  156  will have different orientations than what has been described. Furthermore, there is no requirement that in all versions of the invention in which the handpiece  20  is capable of directing a purge flow through the suction conduit of the cutting accessory  22  that the handpiece also have a switch assembly for controlling the rate of the purge flow. Similarly, in other versions of the invention, by appropriately designing the components, it may be possible to provide one of two purge flows to the suction conduit; a first low-pressure flow and a second high-pressure flow. This arrangement may be possible by constructing the handpiece so that only after irrigation bore opening  178  is placed in full registration with the valve member opening  182  does the reed switch, upon further actuation of the slide lever  40 , close.  
         [0083]    Moreover, in other versions of the invention, a switch assembly for regulating the energization of the suction pump  38  may be built into the handpiece. This switch assembly may include a second reed switch that is actuated by magnet  208  or a second magnet that is displaced by the actuation of slide lever  40 . Depending on the open/closed state of this reed switch, the control console  28  may either increase or decrease the suction drawn by pump  38 .  
         [0084]    Therefore, it is an object of the appended claims to cover all such modifications as come within the true spirit and scope of this invention.