Patent Publication Number: US-2007100276-A1

Title: Apparatus and methods for clearing obstructions from surgical cutting instruments

Description:
REFERENCE TO RELATED APPLICATION  
      The present application is a continuation of U.S. patent application Ser. No. 11/359,885, filed Feb. 21, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 11/187,604, filed Jul. 7, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 10/782,489, filed Feb. 18, 2004. The above referenced applications are commonly owned with the present application, and the contents thereof are hereby incorporated by reference in their entirety as though fully set forth herein. 
    
    
     BACKGROUND  
      1. Field of the Invention  
      The present invention generally relates to systems, methods and apparatus for clearing obstructions from surgical cutting instruments. More particularly, the present invention generally relates to medical devices which use suction to remove detritus from arthroscopic shaving and tissue cutting devices during an arthroscopic procedure without the removal thereof from the incision.  
      2. Description of the Related Art  
      Surgical cutting instruments such as mechanical shaving systems or microdebriders are well known for use in treating injured tissue in various bodily locations, such as joints. Many conventional cutting instruments operate by continuously rotating or by reciprocal rotation of a cutting edge. Such cutting instruments may be used in conjunction with the provision of irrigation fluid to the surgical site, and with the provision of a suction source to aspirate cut bodily tissue and irrigation fluid from the surgical site. The suction source also serves to draw tissue to the cutting edge before the tissue is debrided.  
      A common problem associated with conventional cutting instruments is clogging of the opening of the cutting edge from tissue that has not been cleanly severed, or is too large in diameter to fit through the opening in the cutting edge. The clogged cutting instrument must be removed from the arthroscopic site and the suction has to be stopped. Then, a physician or assistant has to manually clear the obstructing detritus from the cutting instrument in order to proceed with the surgical procedure. Many times, the physician is unable to remove obstructing matter from the instrument and must use a new instrument to continue surgery. Accordingly, clogging of such cutting instruments can cause a significant time delay in arthroscopic surgery and also result in additional costs due to the use of additional cutting instruments.  
      Previous inventions have attempted to reduce or eliminate problems associated with clogging of surgical cutting instruments. For example, U.S. Pat. No. 5,782,795 to Bays (Bays) describes a surgical suction cutting instrument with internal irrigation. The apparatus comprises an outer tubular member and an inner tubular member rotatably received in the outer tubular member. The distal end of the inner tubular member forms a cutting edge, and an aspiration lumen is formed within the inner tubular member. Further, an elongate tubular member is attached to the outer tubular member and configured to supply irrigation fluid to the cutting edge of the instrument.  
      During operation, the rotating cutting edge of the inner member engages and debrides tissue, and irrigation fluid from the elongate tubular member is provided to the cutting chamber. The debrided tissue and irrigation fluid are continuously removed through the aspiration lumen of the inner tubular member. By supplying irrigation fluid to the cutting chamber, the fluid can flush tissue and reduce clogging in the cutting chamber.  
      Apparatus and methods for rapidly and efficiently removing obstructing matter from a surgical cutting instrument are desirable.  
      Apparatus and methods for removing obstructing matter from a surgical cutting instrument without removing the instrument from the surgical site, thereby saving operating time, are further desired.  
      It is also desired to provide apparatus and methods for removing obstructing matter from a surgical cutting instrument within the surgical site without having to turn off a suction device coupled to the cutting instrument.  
      It yet further desired to provide apparatus and methods for removing obstructing matter from a surgical cutting instrument that can be used in conjunction with existing surgical suction cutting instruments.  
     SUMMARY OF THE INVENTION  
      In view of the foregoing, it is an object of the present embodiments to provide an apparatus and methods for rapidly and efficiently removing obstructing matter from a surgical cutting instrument.  
      It is also an object of the present embodiments to provide apparatus and methods for removing obstructing matter from a surgical cutting instrument without removing it from the surgical site, thereby saving operating time.  
      It is a further object of the present embodiments to provide apparatus and methods for removing obstructing matter from a surgical cutting instrument within the surgical site without having to turn off a suction device coupled to the cutting instrument.  
      It is still a further object of the present embodiments to provide apparatus and methods for removing obstructing matter from a surgical cutting instrument that can be used in conjunction with existing surgical suction cutting instruments.  
      These and other objects of the present embodiments may be accomplished by providing apparatus comprising means for interrupting and means for flushing. The means for interrupting may be configured to interrupt aspiration flow in tubing coupled to the cutting instrument, while the means for flushing may be situated distal to the means for interrupting and configured to flush fluid in the tubing in a distal direction. The means for flushing urges fluid distally, towards the surgical site, to flush obstructions away from the cutting instrument. The term fluid may, of course, refer to either a gas or liquid.  
      In an embodiment, methods and devices for clearing obstructions from an aspiration lumen of a medical device, such as a cutting or shaving device, may include an outer tube and an inner tube having a cutting element disposed at the distal end of the inner tube, and an aspiration lumen extending through the inner tube.  
      In an embodiment, a flush lumen may be coupled to the aspiration lumen such that an obstruction may be cleared by delivering a gas through the aspiration lumen. A valve may be included to separate the flush lumen from the aspiration lumen until the valve is opened when a user operates the actuator. The valve may be open for a short time so that the area being treated is not overly inflated. In some embodiments, the valve may be open for less than 0.5 second or less than 0.3 second. The volume of gas passing through the open valve may be less than 500 ml to prevent excessive inflation of the area being treated.  
      In an embodiment, a gas holding chamber may be provided which holds the gas that will be used to clear the aspiration lumen when the valve is opened. The gas holding chamber may be adapted such that it expands when gas is provided thereto collapses when gas leaves the chamber. The elastic expansion of the gas holding chamber may be adapted such that the chamber urges the gas through the flush lumen.  
      In an embodiment, a flow element may be used to regulate delivery of the gas from a source of pressurized gas to the gas holding chamber. The flow element may be any suitable element, including a valve, or a fixed flow element. A fixed flow element may be sized to fill the gas holding chamber relatively slowly compared to the rate at which gas leaves the chamber when flushing the aspiration lumen. A flow element may provide direct pressure communication between the gas holding chamber and the source of pressurized gas.  
      Still further embodiments of the present invention are disclosed. Each embodiment is based on the principle of first interrupting aspiration in a lumen of the mechanical shaver handle and/or a lumen of the inner cutting member coupled to the mechanical shaver handle. Then, using a means for flushing, fluid situated distal to the means for interrupting is flushed in a distal direction to flush away obstructions. Alternative embodiments of the present invention based on these principles are described in detail herein below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above brief description as well as further objects, features and advantages of the methods and apparatus of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings in which:  
       FIG. 1  is a schematic of a hypothetical surgical cutting instrument that may be used in conjunction with apparatus of the present invention;  
       FIGS. 2A-2B  are, respectively, a side view and a side sectional view of a first embodiment of the present invention, which may be used to facilitate removal of obstructions from the cutting instrument of  FIG. 1 ;  
       FIGS. 3A-3C  are, respectively, side sectional views of the apparatus of  FIGS. 2A-2B  in fluid aspirating, interrupting and flushing states;  
       FIGS. 4A-4C  are, respectively, side sectional views of an alternative embodiment of the apparatus of  FIGS. 2-3  in fluid aspirating, interrupting and flushing states;  
       FIGS. 5A-5D  are side views of a further alternative embodiment of the present invention in an aspirating state, fluid interrupting states, and a flushing state;  
       FIGS. 6A-6C  are, respectively, side sectional views of an alternative embodiment of the present invention in fluid aspirating, interrupting and flushing states;  
       FIGS. 7A-7C  are, respectively, a side view of a further alternative embodiment of the present invention in a fluid aspirating state, and side sectional views of the apparatus in fluid interrupting and flushing states;  
       FIG. 8  is an alternative embodiment of the invention described in  FIGS. 7A-7C ;  
       FIG. 9  is an alternative embodiment of the present invention showing means for interrupting and means for flushing disposed within a handle of a surgical cutting instrument;  
       FIG. 10  is an alternative embodiment of the apparatus of  FIG. 9 ;  
       FIG. 11  is a side view of two components of a conventional disposable shaver blade set;  
       FIG. 12  is a side view depicting the two components of  FIG. 11  in an assembled state;  
       FIG. 13  is a side view of a disposable shaver blade set provided in accordance with an embodiment;  
       FIGS. 14A-14B  are, respectively, a side view and a front view of a housing configured for use with the disposable shaver blade set of  FIG. 13 ;  
       FIG. 15  is a side-sectional view depicting the housing of  FIG. 14 ;  
       FIGS. 16A-16C  are, respectively, side views depicting the housing of  FIG. 14  used in conjunction with the disposable shaver set of  FIG. 13 , and two alternative embodiments thereof;  
       FIGS. 17A-17B  are, respectively, a side view and a side-sectional view of an alternative embodiment of  FIG. 16 ;  
       FIGS. 18A-18C  are, respectively, side-sectional views of a further alternative embodiment of the present invention in a fluid aspirating state, a fluid interrupting state and a fluid flushing state;  
       FIGS. 19A-19B  are, respectively, a side views of an alternative embodiment and a side view of a means for flushing configured for use with the present invention;  
       FIG. 20  is a side-sectional view illustrating the components shown in  FIG. 19A ;  
       FIGS. 21A-21B  are, respectively, side-sectional views of a further alternative embodiment in a fluid interrupting state and a fluid flushing state;  
       FIGS. 22A-22C  are, respectively, side-sectional views of a further alternative embodiment in a fluid aspirating state, a fluid interrupting state and a fluid flushing state;  
       FIG. 23  is a plan view of one embodiment;  
       FIG. 24  is a plan view of an alternative embodiment;  
       FIG. 25  is a plan view of another alternative embodiment;  
       FIG. 26  is a plan view of yet another alternative embodiment;  
       FIG. 27  is a cross-sectional view of an embodiment; and  
       FIG. 28  is a plan view of yet another embodiment. 
    
    
      While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawing and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.  
     DETAILED DESCRIPTION  
      Referring to  FIG. 1 , a surgical suction cutting instrument that may be used in conjunction with apparatus of the present invention is described. Surgical suction cutting instrument  4  may be any conventional cutting instrument known in the art, and the particular features depicted in  FIG. 1  are provided merely for illustrative purposes. In the embodiment depicted in  FIG. 1 , cutting instrument  4  comprises handle  6  having proximal and distal ends, and further comprises outer shaft  8  having proximal and distal ends. The proximal end of outer shaft  8  is coupled to the distal end of handle  6 , while the distal end of outer shaft  8  comprises opening  10 , as depicted in  FIG. 1 .  
      Outer shaft  8  houses inner shaft  11  having proximal and distal ends. The proximal end of inner shaft  11  is coupled to a motor (not shown), which is disposed in handle  6  and configured to drive rotation of cutting blade  12  on the distal end of shaft  11  when actuation means  16  is actuated. As will be apparent to those skilled in the art, opening  10  is configured to permit tissue to be cut by rotation of cutting edge  12  with respect to outer shaft  8 .  
      Referring still to  FIG. 1 , surgical suction cutting instrument  4  further comprises electrical supply means  13  and aspiration line  14  coupled to handle  6 . Electrical supply means  13  is coupled to the motor, thereby driving rotation of cutting edge  12 .  
      In  FIG. 1 , aspiration line  14  is coupled to aspiration tubing  22 , which has proximal and distal ends. The proximal end of aspiration tubing  22  is coupled to a suction device (not shown), while the distal end of aspiration tubing  22  is coupled to aspiration line  14  via port  15 . Alternatively, port  15  may be omitted, such that aspiration tubing  22  and aspiration line  14  are in effect the same line.  
      When the suction device is turned on, suction is provided through lumen  23  of aspiration tubing  22 , which is in fluid communication with the distal end of outer shaft  8 . Accordingly, suction is provided to cutting edge  12  and opening  10  to draw tissue towards the cutting edge, and also to facilitate removal of debrided tissue and irrigation fluid from a surgical site.  
      Referring now to  FIGS. 2A-2B , a first embodiment of the present invention is described. Apparatus  20  is configured to facilitate removal of clogged tissue from a surgical cutting instrument, such as cutting instrument  4  of  FIG. 1 .  
      In an embodiment, the apparatus may include an actuation means having a preferably bulb-shaped exterior surface. The actuation means is configured to be useable with aspiration tubing coupled to the cutting instrument, such that the actuation means encloses the aspiration tubing during use. Apparatus  20  comprises actuation means  24  having proximal and distal regions  25  and  26 , respectively, as shown in  FIG. 2A . Actuation means  24  is configured to be used in conjunction with at least one piece of aspiration tubing  22  that is in fluid communication with cutting instrument  4 , for example, as depicted in  FIG. 1 .  
      Actuation means  24  comprises exterior surface  30 , which preferably is a bulb-shaped member that is adapted to be grasped by a human hand. Exterior surface  30  may be manufactured using a suitable compound, such as rubber, that allows the exterior surface to be compressed in an inward direction when a force is applied and then return to its original, non-compressed state when the compressive force is removed.  
      A means for interrupting may include at least one inward protrusion disposed between the bulb-shaped exterior surface and a section of the aspiration tubing. The means for flushing may include at least one fluid chamber disposed between the exterior surface and the aspiration tubing at a location distal to the means for interrupting. During use, the aspiration tubing may be configured to aspirate matter, such as debrided tissue and irrigation fluid, from a surgical site. When no external compressive forces are applied to the actuation means, the inward protrusion does not impose substantial forces upon the aspiration tubing, thereby allowing aspiration to be achieved throughout the tubing. When an obstruction is present in the cutting instrument, the bulb-shaped exterior of the actuation means may be compressed to cause the inward protrusion to compress a section of aspiration tubing. This inhibits aspiration in the tubing distal to the inward protrusion.  
      Apparatus  20  further includes means for interrupting  32 , as shown in  FIG. 2B . In the embodiment of  FIGS. 2-3 , means for interrupting  32  comprises at least one inward protrusion  34  that is disposed within exterior surface  30  and configured to selectively compress aspiration tubing  22 . Inward protrusion  34  preferably has a curved shape with at least one apex or engagement point  35 , as shown in  FIG. 2B . Apex  35  of inward protrusion  34  is configured to selectively compress an exterior surface of aspiration tubing  22 , and may fully encircle tubing  22 , contact the tubing at one location, contact the tubing at two opposing locations, or contact the tubing in any other manner suitable for applying compressive force upon tubing  22 .  
      If apex  35  fully encircles tubing  22 , then the provision of a bulb-shaped exterior surface  30  may be desirable. However, where two opposing apexes are provided, it may be desirable to provide exterior surface  30  with indicia (not shown) corresponding to the circumferential positioning of apexes  35  beneath exterior surface  30 . Such indicia allows a user to compress exterior surface  30  at a location that will most effectively cause compression of the apexes to actuate the device, as described hereinbelow. Alternatively, when two opposing apexes  35  are employed, exterior surface  30  may comprise an elliptical or oval shape, so that a physician can simply compress the opposing surfaces to effectively cause compression of the apexes.  
      Inward protrusion  34  may be formed from the same material as exterior surface  30  of actuation means  24 , or alternatively, may be manufactured using a separate material that is bonded to an interior region of exterior surface  30 . If a separate material is used, it may be desirable to provide inward protrusion  34  as a more rigid member than exterior surface  30 , so that compression of exterior surface  30  will result in a stronger and more direct compression of tubing  22 .  
      Apparatus  20  may comprise at least one proximal fluid chamber  42  formed between aspiration tubing  22  and exterior surface  30 , at a location proximal to apex  35 . Further, recess  38  may be formed between inward protrusion  34  and exterior surface  30 , as depicted in  FIG. 2B . Alternatively, these regions may be solid, such that recess  38  and/or fluid chamber  42  are omitted entirely.  
      Referring still to  FIG. 2B , apparatus  20  further comprises means for flushing  43 , which in the embodiment of  FIGS. 2-3  comprises at least one fluid chamber  44  formed between aspiration tubing  22  and exterior surface  30 . Fluid chamber  44  of means for flushing  43  is disposed at a location distal to apex  35 , as shown in  FIG. 2B .  
      Referring now to  FIGS. 3A-3C , use of apparatus  20  of  FIGS. 2A-2B  is described for facilitating removal of clogged tissue from cutting instrument  4  during a surgical procedure, such as arthroscopic surgery. As will be apparent to one skilled in the art, irrigating fluid may be delivered to the surgical site, while aspiration tubing  22  is employed to aspirate irrigating fluid and cut tissue from the surgical site. An irrigation line (not shown) may be used in conjunction with apparatus  20  of the present invention, if desired.  
      In  FIG. 3A , actuation means  24  is shown in an “open” or fully aspirating state. The proximal end of aspiration tubing  22  is coupled to a suction device, and aspiration tubing  22  is in fluid communication with the distal end of cutting instrument  4 . Accordingly, irrigation fluid and cut tissue from the surgical site will be aspirated through opening  10  of cutting instrument  4 , and then through tubing  22  in a proximal direction, as indicated by the arrows in  FIG. 3A .  
      As noted above, one common problem associated with use of conventional surgical cutting instruments during arthroscopic procedures is the tendency of cut tissue to clog opening  10  or cutting edge  12  of the cutting instrument. In accordance with one aspect of the present invention, once the cutting instrument becomes clogged, a physician may manually compress exterior surface  30  to cause apex  35  to compress a section of aspiration tubing  22 , as shown in  FIG. 3B . This inhibits aspiration distal to apex  35 , such that no substantial fluid flow occurs in tubing  22  distal to apex  35 .  
      Further compression of the bulb-shaped exterior compresses the fluid chamber of the flushing means. This causes compression of a section of tubing distal to the means for interrupting. Fluid in the aspiration tubing, distal to the means for interrupting, then is flushed in a distal direction. By causing fluid in the aspiration tubing to flow in a distal direction, the fluid flushes clogged tissue away from the cutting instrument. Referring now to  FIG. 3C , when a physician applies further compression to actuation means  24 , means for flushing  43  is actuated. Specifically, the compression of exterior surface  30  towards tubing  22  causes fluid in chamber  44  to compress tubing  22 . The compression of tubing  22  causes irrigation fluid in tubing  22  that is distal to apex  35  to be urged in a distal direction, i.e., towards opening  10  and cutting edge  12 . Since apex  35  remains sealingly engaged with aspiration tubing  22 , fluid in tubing  22  will be flushed in a distal direction.  
      By applying pressure to fluid in tubing  22  and flushing fluid in a distal direction, the distally flowing fluid flushes clogged tissue away from opening  10  and cutting edge  12  of the cutting instrument. Once compression is released, this tissue then may be introduced back into the cutting instrument, reduced in size, and then effectively aspirated through tubing  22 .  
      In an embodiment, and in accordance with principles described herein, the cutting instrument need not be removed from the surgical site, or a replacement instrument need not be provided thereto, because the obstructing tissue is effectively removed at the surgical site. Further, the suction device need not be stopped to remove the obstruction, since aspiration is blocked by the means for interrupting. The surgical procedure need therefore not be substantially delayed, nor equipment need be replaced.  
      Advantageously, in accordance with one aspect of the present invention, a physician may remove obstructing tissue from the surgical cutting instrument using actuation means  24  without having to remove the cutting instrument from the surgical site and manually remove the clogged tissue. Also, the surgeon is not expected to have to replace the cutting instrument with a different instrument, thereby saving time and money.  
      Upon successful removal of clogged tissue, the physician can remove the compressive forces imposed upon actuation means  24 , thereby causing actuation means  24  to return to its original shape, depicted in  FIG. 3A . At this time, aspiration throughout the tubing is restored.  
      Referring now to  FIGS. 4A-4C , an alternative embodiment of apparatus  20  of  FIGS. 2-3  is described. Apparatus  20 ′ is similar to apparatus  20 , except as noted hereinbelow. In particular, an alternative means for flushing, comprising at least one interior compression member  44 ′, is employed. Interior compression member  44 ′ is configured to apply a direct compressive force to aspiration tubing  22 , as described hereinbelow.  
      Apparatus  20 ′ preferably further comprises at least one support structure  47  disposed between exterior surface  30  and interior compression member  44 ′, as shown in  FIG. 4A . Fluid chambers  46  may be formed between support structures  47 , exterior surface  30 , and/or interior compression member  44 ′. Support structures  47  help translate compressive forces from exterior surface  30  to interior compression member  44 ′, while fluid chambers  46  conform to provide flexibility and comfort during operation.  
      The operation of apparatus  20 ′ is similar to use of apparatus  20 , as described in  FIGS. 3A-3C  hereinabove. In a first step, actuation means  24  is provided in an “open” or fully aspirating state, as shown in  FIG. 4A . Once cutting instrument  4  becomes clogged, a physician may manually compress exterior surface  30  of actuation means  24  to cause apex  35  of means for interrupting  34  to sealingly compress a section of aspiration tubing  22 , as shown in  FIG. 4B . This inhibits aspiration distal to apex  35 .  
      Referring now to  FIG. 4C , apparatus  20 ′ is shown when a physician applies further compression to exterior surface  30  of actuation means  24 . The compression of exterior surface  30  towards tubing  22  causes support structures  47  to translate the compressive force to interior compression member  44 ′, which in turn directly compresses a portion of tubing  22  distal to apex  35 . The direct compression of tubing  22  causes irrigation fluid in tubing  22  that is distal to apex  35  to be urged in a distal direction, i.e., towards opening  10  and cutting edge  12 . As described hereinabove, by applying pressure to fluid in tubing  22  and causing the fluid to flow in a distal direction, the fluid flushes clogged tissue away from the cutting edge of the instrument.  
      In the embodiments of  FIGS. 2-4  hereinabove, it will be apparent to one skilled in the art that either air or liquid may be disposed within chambers  38 ,  42 ,  44 ,  46  and  49 . In particular, the provision of liquid in chambers  44 ,  46  and  49  is expected to facilitate compression of tubing  22 . Alternatively, any of the fluid chamber depicted hereinabove may be omitted and replaced with solid regions.  
      In an alternative embodiment, fluid trapped in chambers  44  of  FIGS. 3A-3C  may be delivered to aspiration tubing  22  to facilitate removal of clogged tissue in the cutting instrument. In this embodiment, a section of tubing  22 , situated between apex  35  and distal region  26 , may comprise a plurality of small perforations (not shown). In the step described in  FIG. 3C , fluid disposed in chamber  44  may be infused into tubing  22  via the plurality of small perforations. The infused fluid then will flow in a distal direction through lumen  23  to facilitate removal of clogged tissue. Similarly, for the embodiment described in  FIGS. 4A-4C , perforations may be provided in tubing  22  and liquid disposed in chambers  49  may be infused into lumen  23  upon compression of exterior surface  30 .  
      Further, as will be apparent to one skilled in the art, varying degrees of aspiration tubing stiffness may be provided. For example, relatively flexible aspiration tubing  22  may be provided when air is disposed in chambers  44  and  49 , to ensure that the air may compress the tubing. By contrast, relatively rigid aspiration tubing may be provided when liquid is disposed in chambers  44  and  49  to facilitate compression of the relatively stiff tubing. In any embodiment, tubing  22  also may comprise at least one relatively flexible segment and at least one relatively rigid segment.  
      In accordance with another aspect of the present invention, it should be noted that apparatus  20  may be used in conjunction with any existing cutting instrument  4 . Apparatus  20  may be provided securely disposed about tubing  22 , or alternatively, apparatus  20  may be provided as a separate component. In the latter case, apparatus  20  may slide over tubing  22  and a user may secure proximal and distal regions  25  and  26  to tubing  22  at a desired location on the tubing. For example, apparatus  20  may be secured about tubing  22  using a suitable adhesive, thermal plastic bond, or using mechanical means such as clamps. A physician therefore may vary the longitudinal positioning of apparatus  20  with respect to tubing  22 . However, it may be desirable to have apparatus  20  disposed towards the distal end of tubing  22  so that the apparatus is in relatively close proximity to cutting instrument  4 . In an embodiment, an actuation means may include first and second handles configurable to actuate first and second rollers. The first and second rollers are configured to move within respective channels in the handles. The first an second rollers may be configured to serve both as the means for interrupting aspiration and the means for flushing fluid in the aspiration tubing.  
      Referring now to  FIGS. 5A-5D , an alternative embodiment of the present invention is described for facilitating removal of clogged tissue during a surgical procedure. Apparatus  120  comprises an actuation means having first handle  124   a  and second handle  124   b . First handle  124   a  has channel  132   a  disposed therein, while second handle  124   b  has channel  132   b  disposed therein, as shown in  FIG. 5A . First and second handles  124   a  and  124   b  are coupled together at their respective proximal ends using pivot pin  130 , which is disposed to partially or fully surround aspiration tubing  22 .  
      Apparatus  120  preferably further comprises springs  134   a  and  134   b , each having proximal and distal ends. The proximal ends of springs  134   a  and  134   b  preferably are coupled to the proximal ends of handles  124   a  and  124   b , respectively, while the distal ends of springs  134   a  and  134   b  are coupled to the distal ends of handles  124   a  and  124   b , respectively, as shown in  FIG. 5A . Alternatively, the proximal ends of the springs may be left unsecured, so that the proximal ends of the springs may deflect when the device is actuated, as described further in  FIGS. 5C-5D  hereinbelow.  
      Apparatus  120  further comprises means for interrupting and means for flushing. In the embodiment depicted herein, both the means for interrupting and means for flushing are the same, and they comprise first and second rollers  128   a  and  128   b . First and second rollers  128   a  and  128   b  preferably comprise an outer diameter that is slightly smaller than height h of channels  132   a  and  132   b , thereby permitting the rollers to move longitudinally within their respective channels, as described hereinbelow.  
      In an aspirating state, the rollers are disposed at a proximal section of their respective channels, and do not impose substantial forces upon the aspiration tubing. When obstructing tissue is present at the cutting edge of the instrument, the handles may be compressed to advance the rollers distally within the channels. As compression is applied aspiration flow in the tubing may be interrupted. Then, the rollers may be urged distally to distally advance the fluid in the tubing distal to the rollers. The distally urged fluid flushes the surgical site and facilitates removal of clogged tissue from the cutting instrument. Referring still to  FIG. 5A , apparatus  120  is depicted in an “open” or fully aspirating state, whereby the distal ends of handles  124   a  and  124   b  are widely separated. In the aspirating state, rollers  128   a  and  128   b  are disposed in proximal sections of their respective channels. Rollers  128   a  and  128   b  do not apply substantial forces to tubing  22  in the fully aspirating state.  
      Referring now to  FIG. 5B , a physician may realize cutting instrument  4  has become clogged during a surgical procedure. When this occurs, the physician applies a compressive force to first and second handles  124   a  and  124   b . The compressive force causes the proximal ends of the handles to rotate about pivot point  130 , and further causes the distal ends of the handles to be drawn closer together, as depicted in  FIG. 5B .  
      As handles  124   a  and  124   b  are compressed together, rollers  128   a  and  128   b  apply a compressive force upon aspiration tubing  22 , as shown in  FIG. 5B . The compressive force of the rollers pinches the tubing and inhibits further aspiration of fluid in lumen  23  (distal to the rollers). When relatively light compressive forces are applied to handles  124   a  and  124   b , springs  134   a  and  134   b  do not substantially displace, and therefore serve to confine rollers  128   a  and  128   b  at the proximal sections of their respective channels.  
      Referring now to  FIG. 5C , as a physician further compresses handles  124   a  and  124   b , proximal regions of springs  134   a  and  134   b  are displaced against the rollers. Displacement of springs  134   a  and  134   b , above a predetermined compression threshold, causes rollers  128   a  and  128   b  to advance distally within their respective channels.  
      Referring now to  FIG. 5D , still further compression of handles  124   a  and  124   b  causes rollers  128   a  and  128   b  to be advanced towards the distal end of channels  132   a  and  132   b , respectively. Rollers  128   a  and  128   b  remain engaged with tubing  22 , such that their advancement flushes fluid in lumen  23 , situated distal to the rollers, in a distal direction.  
      By applying pressure to fluid in tubing  22  and flushing the fluid in a distal direction, the fluid flow flushes clogged tissue from opening  10  and cutting edge  12 . Upon successful removal of clogged tissue, the physician can remove the previously-applied compressive forces imposed upon handles  124   a  and  124   b , thereby causing the handles to return to their original positions, depicted in  FIG. 5A .  
      As will be apparent to one skilled in the art, characteristics of springs  134   a  and  134   b  may be varied to vary the manual force required to actuate apparatus  120 . However, the springs preferably are stiff enough so that they do not substantially displace until tubing  22  first is compressed. After a threshold force is applied to compress tubing  22 , then the springs are configured to displace enough to permit rollers  128   a  and  128   b  to be advanced distally in channels  132   a  and  132   b.    
      Further, the distance between pivot point  130  and the proximal ends of channels  132   a  and  132   b  may be varied to vary the force required to actuate apparatus  120 . For example, increasing this distance may reduce the force required to actuate apparatus  120 , since greater leverage is provided.  
      In an embodiment an actuation means having a preferably bulb-shaped exterior surface and at least one arcuate spring disposed within the exterior surface may be employed. A roller may be coupled to a distal end of each arcuate spring, and the rollers may be configured to advance within roller guides disposed within the actuation means. Referring now to  FIGS. 6A-6C , a further alternative embodiment of the present invention is described for clearing obstructions from cutting instrument  4 . Apparatus  220  comprises actuation means  224 , which comprises exterior surface  230 . Apparatus  220  further comprises means for interrupting and means for flushing, which, in the embodiment of  FIGS. 6A-6C , are the same. The means for interrupting and the means for flushing comprise first and second arcuate springs  240   a  and  240   b , and further comprise rollers  244   a  and  244   b.    
      Arcuate springs  240   a  and  240   b  have proximal and distal ends and a central region  241  disposed therebetween. The proximal ends of arcuate springs  240   a  and  240   b  are fixedly attached to an interior portion of exterior surface  230  at fixation point  260 , as shown in  FIG. 6A . The distal ends of arcuate springs  240   a  and  240   b  are coupled to rollers  244   a  and  244   b , respectively. Rollers  244   a  and  244   b  preferably are coupled to their respective springs using a central pin  245 , as depicted in  FIG. 6A .  
      In an embodiment, the bulb-shaped exterior may be compressed during use to compress a central region of the arcuate spring. Compression of the spring urges the rollers by way of the roller guides inwardly to compress the aspiration tubing and interrupt aspiration flow.  
      When no external forces are applied to apparatus  220 , central regions  241  of arcuate springs  240   a  and  240   b  are configured to assume the curved configuration depicted in  FIG. 6A . When compressive forces are applied, the arcuate springs may be deformed accordingly, as will be described in greater detail hereinbelow.  
      Apparatus  220  further comprises first and second roller guides  250   a  and  250   b , each having proximal region  251  and distal region  252 . Each proximal region  251  transitions into distal region  252  via curvature or slant  253 . Each proximal region  251  is configured to house rollers  244   a  and  244   b  in the aspirating state, as depicted in  FIG. 6A  and described in greater detail hereinbelow.  
      In accordance with one aspect of the present invention, apparatus  220  is configured for use with existing surgical cutting instruments, such as cutting instrument  4  of  FIG. 1 . Apparatus  220  may be affixed to tubing  22 , for example, at proximal and distal regions  225  and  226 , or alternatively, apparatus  220  may slide longitudinally over the tubing. In the latter embodiment, a physician may insert the tubing through a central region of apparatus  220 , and then position apparatus  220  at a desired location with respect to the tubing.  
      The operation of apparatus  220  is similar to use of apparatus  20 , as described in  FIGS. 3A-3C  hereinabove. In a first step, apparatus  220  is provided in an “open” or fully aspirating state, whereby no substantial external forces are applied to apparatus  220 . In this state, central regions  241  of arcuate springs  240   a  and  240   b  assume the curved configuration depicted in  FIG. 6A . At this time, rollers  244   a  and  244   b  are disposed within proximal regions  251  of their respective roller guides  250   a  and  250   b . Accordingly, rollers do not impose a substantial force upon tubing  22  during the aspirating state, as shown in  FIG. 6A . As noted above, when the proximal end of tubing  22  is coupled to a suction device (not shown), irrigation fluid and cut tissue from the surgical site will be aspirated through aspiration tubing  22  in a proximal direction, as indicated by the arrows in  FIG. 6A .  
      Referring now to  FIG. 6B , once suction tubing  22  becomes clogged, a physician may manually compress exterior surface  230  to compress central region  241  of arcuate springs  240   a  and  240   b . Compression of the arcuate springs causes rollers  244   a  and  244   b  to advance distally, since the proximal ends of the arcuate springs remain fixed at points  260 .  
      When compression is applied, slant  253  urges rollers  244   a  and  244   b  in an inward direction, i.e., towards tubing  22 , as shown in  FIG. 6B . Rollers  244   a  and  244   b  sealingly compress a section of aspiration tubing  22 , thereby inhibiting suction within lumen  23  (distal to the rollers).  
      Further compression of the bulb-shaped exterior of the actuation means may guide the rollers distally while pinching flow in the tubing. This flushes fluid in the aspiration tubing, situated distal to the rollers, in a distal direction to facilitate removal of obstructing tissue. Referring now to  FIG. 6C , apparatus  220  is shown when a physician applies further compression to exterior surface  230  of actuation means  224 . The compression of exterior surface  230  towards aspiration tubing  22  urges springs  240   a  and  240   b  to straighten, thereby advancing rollers  244   a  and  244   b  in a distal direction, as shown in  FIG. 6C . The rollers are guided by distal region  252  of roller guides  250   a  and  250   b , which ensure that the rollers remain firmly engaged with tubing  22 . The advancement of rollers  244   a  and  244   b  causes irrigation fluid in tubing  22  that is distal to the rollers to be flushed in a distal direction, i.e., towards opening  10  and cutting edge  12 , thereby flushing obstructions away from the cutting instrument.  
      Upon successful removal of clogged tissue, the surgeon can remove the previously-applied compressive forces, thereby causing springs  240   a  and  240   b  to return to their preferred arcuate shapes, as depicted in  FIG. 6A . At this time, aspiration throughout the tubing is restored, and will remain in the aspirating state until the surgeon applies further compressive forces to remove subsequently clogging tissue.  
      As will be apparent to one skilled in the art, characteristics of springs  240   a  and  240   b  may be varied to vary the manual force required to actuate apparatus  220 . However, the springs should be stiff enough to cause rollers  244   a  and  244   b  to compress tubing  22  without substantially bowing inward first, i.e., the springs will not merely bow inward before the tubing is displaced. After a threshold force is applied to compress tubing  22 , then the springs are configured to displace enough to permit rollers  244   a  and  244   b  to be advanced distally in channels  250   a  and  250   b.    
      Further, it will be apparent to one skilled in the art that, in lieu of two or more roller guides  250   a  and  250   b , one continuous, circumferentially-shaped roller guide  250  may be disposed within exterior surface  230 . Such a continuous and circumferential guide may be adapted to guide each roller  244 . In such an embodiment, a bulb-shaped exterior surface  230  may be desirable.  
      However, where two rollers and two roller guides are employed, as depicted in  FIGS. 6A-6C , it may be desirable to provide exterior surface  230  with indicia (not shown) corresponding to the circumferential positioning of springs  244   a  and  244   b  beneath exterior surface  230 . Such indicia allows a user to compress exterior surface  230  at a location that will most effectively actuate springs  240   a  and  240   b . Alternatively, when two springs and two roller guides are employed, exterior surface may comprise an elliptical or oval shape, so that a physician can simply compress the opposing regions to effectively actuate the device.  
      Finally, it will be apparent that although two rollers  244   a  and  244   b  are depicted, greater or fewer rollers may be employed to achieve the effects described hereinabove.  
      Referring now to  FIGS. 7A-7C , a further alternative embodiment of the present invention is described. Apparatus  320  comprises roller  324  and housing  330 , which are configured to be used in conjunction with aspiration tubing  22  having lumen  23  disposed therethrough. In this embodiment, roller  324  serves as the actuation means, and also as the means for interrupting and means for flushing, as will be described in greater detail hereinbelow.  
      Housing  330  preferably comprises a rectangular shape, although other shapes may be employed. Channel  334  having proximal region  336 , central region  337  and distal region  338  is disposed within housing  330 , as shown in  FIG. 7A . In a preferred embodiment, distal region  338  spans a greater length than proximal region  336 .  
      Roller  324  is coupled to roller axle  325 , as shown in  FIG. 7B . Roller axle  325  preferably has an outer diameter that is slightly smaller than height h′ of channel  334 , thereby permitting roller  324  to be advanced longitudinally within channel  334  via roller axle  325 .  
      Tubing  22  is disposed through proximal and distal openings  351  and  352  of housing  330 , as depicted in  FIG. 7B . The tubing may be inserted through the proximal and distal openings when roller  324  is situated in proximal region  336  of channel  334 , as shown in  FIG. 7A . Proximal and distal openings  351  and  352  preferably are disposed just above lower surface  354  of housing  330 , so that tubing  22  can rest upon lower surface  354  during operation.  
      A physician may advance apparatus  320  longitudinally with respect to tubing  22  until housing  330  is disposed in a desired location with respect to the tubing. The physician then may secure the position of housing  330  with respect to tubing  22 , e.g., using an adhesive or mechanical means, or leave the housing unsecured.  
      Referring to  FIG. 7A , apparatus  220  is provided in an “open” or fully aspirating state, whereby roller  324  is disposed in proximal region  336  of channel  334 . At this time, roller  324  is constrained at such a distance from tubing  22  that the roller does not impose a substantial compressive force upon the tubing. This permits aspiration through tubing  22  when the proximal end of the tubing is coupled to a suction device.  
      Referring now to  FIG. 7B , once a cutting instrument coupled to tubing  22  becomes clogged during a surgical procedure, a physician may advance roller  324  distally, either manually or using mechanical means (not shown). It should be noted that roller  324  may be round, as depicted, or alternatively may comprise one or more grooves or raised surfaces to provide a frictional resistance that facilitates actuation by the physician.  
      As roller  324  is advanced distally, the contours of central region  337  cause roller axle  325  to direct roller  324  in an inward direction, i.e., towards tubing  22 . Roller  324  subsequently pinches off a section of tubing  22  by compressing the tubing between the roller and lower surface  354  of housing  330 , as shown in  FIG. 7B . This advancement of roller  324  inhibits suction within lumen  23  (distal to the roller).  
      Referring now to  FIG. 7C , apparatus  320  is shown when a physician further advances roller  324  distally. Roller axle  325  is guided along distal region  338  of channel  334 . During this time, roller  324  applies continuous compression upon tubing  22 , which is compressed against lower surface  354 .  
      The advancement of roller  324  causes irrigation fluid in tubing  22  that is distal to roller  324  to be flushed in a distal direction, i.e., towards opening  10  and cutting edge  12 . As described hereinabove, by applying pressure to fluid in tubing  22  and causing the fluid to flow in a distal direction, the fluid flushes clogged tissue away from cutting edge  12 .  
      Upon successful removal of clogged tissue, a surgeon can retract roller  324  proximally into proximal region  336 , thereby causing roller  324  to become fully or substantially disengaged from tubing  22 . Tubing  22  will return to its uncompressed shape and aspiration will be restored throughout the tubing.  
      Referring now to  FIG. 8 , an alternative embodiment of apparatus  320  of  FIGS. 7A-7C  is described. In  FIG. 8 , apparatus  320 ′ functions similarly to apparatus  320 , except as noted hereinbelow. Apparatus  320 ′ comprises housing  330 ′ having channel  334 ′. Channel  334 ′ comprises proximal section  370 , advancement channel  371  and return channel  372 , which preferably are separated by partition  374 . Apparatus  320 ′ further comprises roller  324  of  FIGS. 7A-7C , which is omitted from  FIG. 8  for clarity.  
      In operation, roller  324  is positioned within proximal section  370  of channel  334 ′ in the aspirating state. Once the cutting instrument becomes clogged, a physician may advance roller  324  distally towards one-way guide  376  of partition  374 . One-way guide  376  causes roller  324  to be advanced distally into advancement channel  371 .  
      When roller  324  is advanced into advancement channel  371 , roller  324  subsequently pinches off a section of tubing  22  by compressing the tubing between the roller and lower surface  351  of housing  330 . At this time, roller  324  inhibits suction within lumen  23  (distal to the roller). As roller  324  is further advanced in advancement channel  371 , irrigation fluid in tubing  22  that is distal to the roller is flushed in a distal direction, i.e., towards cutting edge  12 .  
      When roller  324  is advanced toward the distal end of advancement channel  371 , distal stop  377  of partition  374  may provide resistance to roller axle  325  (see  FIGS. 7B-7C ). A surgeon may apply a slightly greater force upon roller  324  to cause the roller axle to be advanced beyond distal stop  377 .  
      Once the roller axle is advanced beyond distal stop  377 , the roller is returned to proximal region  370  via return channel  372 . In one embodiment, a physician may manually advance roller  324  in a proximal direction through return channel  372  and into proximal region  370 . Alternatively, as will be apparent to one skilled in the art, a spring mechanism (not shown) may be employed to facilitate the return of roller  324  to proximal region  370 , after the roller passes distal stop  377 . It should be noted that, in either the manual or spring-return embodiments, distal stop  377  also may be omitted entirely.  
      With respect to all embodiments described hereinabove, it will be apparent to one skilled in the art that the means for interrupting and means for flushing may be completely separate entities, each actuated using its own separate actuation means. Specifically, the means for interrupting may compress a first section of tubing  22  to interrupt aspiration within the tubing. Then, the means for flushing, which is disposed at a second location along tubing  22  distal to the means for interrupting, subsequently may be actuated to cause irrigation fluid to be flushed towards cutting edge  12 .  
      Additionally, in other embodiments, the means for flushing may be configured to be pressurized. For example, a desired amount of pressure may be built up in a bulb-shaped compressor. Once a desired pressure is reached, the means for flushing is actuated to permit pressurized fluid to compress tubing  22 , thereby resulting in high velocity fluid flow through opening  10  of the cutting instrument. If desired, such pressurized means for flushing can be configured to automatically release fluid once a predetermined pressure threshold is achieved.  
      Referring now to  FIGS. 9-10 , further alternative embodiments of the present invention are described. The embodiments of  FIGS. 2-8  described apparatus for facilitating removal of obstructions from a surgical cutting instrument, whereby the apparatus was disposed substantially or exclusively on a section of aspiration tubing external to the cutting instrument. In the embodiments of  FIGS. 9-10 , similar apparatus are described; however, these embodiments are substantially integrated into a handle of the cutting instrument itself.  
      Referring to  FIG. 9 , apparatus  400  comprises cutting instrument handle  406  having proximal and distal ends. Handle  406  is similar to handle  6  of cutting instrument  4  of  FIG. 1 , except as noted hereinbelow. Like the embodiment of  FIG. 1 , the distal end of handle  406  of  FIG. 9  may be coupled to outer shaft  8  having distal opening  10  (see  FIG. 1 ).  
      Apparatus  400  further comprises motor  409 , which is disposed within handle  406  and configured to drive inner shaft  11  of  FIG. 1 . Electrical supply means  413  is coupled to handle  406 , and is adapted to communicate with multiple components of apparatus  400 , as described hereinbelow.  
      Aspiration tubing  22  having proximal and distal ends also is provided. The proximal end of aspiration tubing  22  is coupled to a suction source (not shown) while the distal end is configured to be selectively placed in fluid communication with cutting edge  12  of the cutting instrument (see  FIG. 1 ).  
      Apparatus  400  further comprises means for interrupting  425  and means for flushing  435 . Means for interrupting  425  is disposed within handle  406  proximal to means for flushing  435 , and preferably is disposed adjacent tubing section  22   a , as depicted in  FIG. 9 . Means for interrupting  425  communicates with electrical supply means  413 , and further communicates with actuation means  419 .  
      Means for flushing  435  is disposed distal to means for interrupting  425 , as depicted in  FIG. 9 , and also communicates with electrical supply means  413  and actuation means  419 . Means for flushing  435  may fully encircle tubing section  22   b , as depicted in  FIG. 9 , or may be disposed adjacent tubing section  22   b.    
      In operation, a proximal end of electrical supply means  413  is coupled to a power source (not shown) and the proximal end of tubing  22  is coupled to a suction source (not shown). The apparatus may be provided in an “open” or fully aspirating state, permitting aspiration of fluid and cut tissue in a proximal direction through tubing  22 . In the fully aspirating state, neither means for interrupting  425  nor means for flushing  435  applies substantial compressive forces upon tubing  22 .  
      Once the cutting instrument becomes clogged, a physician may actuate means for interrupting  425 , e.g., via actuation means  419 . Like the embodiments described hereinabove, means for interrupting  425  is configured to apply compression upon tubing section  22   a  when actuated, thereby interrupting aspiration flow in tubing  22  (distal to section  22   a ).  
      In a next step, means for flushing  435  is actuated, e.g., via actuation means  419 . Also like the embodiments described hereinabove, means for flushing  435  is actuated to apply compressive forces upon tubing section  22   b , thereby flushing fluid in a distal direction. Distally urged fluid flushes clogged tissue away from cutting edge  12  of the cutting instrument.  
      Advantageously, in the embodiment of  FIG. 9 , means for interrupting  425  and means for flushing  435  may comprise various mechanically or electrically actuated means to apply compression to tubing sections  22   a  and  22   b , respectively. For example, means for interrupting  425  may comprise any valve, solenoid, or other mechanism known in the art that may apply a compressive force upon tubing section  22   a  to compress the tubing in a manner as described hereinabove.  
      Similarly, means for interrupting  435  may comprise any valve, solenoid or pneumatic pump configured to apply a compressive force upon tubing section  22   b . In a particularly useful embodiment, means for flushing  435  is configured to apply a circumferential compressive force upon tubing section  22   b  in a proximal to distal direction.  
      As will be apparent to one skilled in the art, a microprocessor and memory (not shown) may be employed to facilitate actuation of means for interrupting  425  and/or means for flushing  435 . In response to data instructions received from the microprocessor, means for interrupting  425  and means for flushing  435  may be actuated accordingly.  
      In a particularly useful embodiment, the microprocessor is programmed to cause means for interrupting  425  to be actuated when actuation means  419 , e.g., a button, is pressed once. The microprocessor then automatically instructs means for flushing  435  to be actuated at a later time, e.g., one second later. Such programming is particularly useful because it eliminates the need for a physician to actuate button  419  multiple times to achieve one cycle of flushing.  
      Alternatively, as will be apparent to one skilled in the art, actuation means  419  may comprise a multi-position switch configured to mechanically actuate means for interrupting  425  and means for flushing  435  in sequence. For example, when actuation means  419  comprises a button, and the button is partially depressed, means for interrupting  425  may be actuated. Then, when the button is fully depressed, means for flushing  435  subsequently is actuated.  
      Although one actuation means  419  has been described for actuating both means for interrupting  425  and means for flushing  435 , other designs may be employed. For example, actuation means  419  may be configured to actuate means for interrupting  425  only, while a second actuation means (not shown) may be disposed on handle  406  to actuate means for flushing  435 . In this embodiment, the microprocessor may have instructions to ensure that means for flushing  435  cannot be actuated when means for interrupting  425  is in an open position.  
      Further, as will be apparent to one skilled in the art, mechanical means similar to those described hereinabove with respect to  FIGS. 2-8  may be employed to actuate means for interrupting  425  and/or means for flushing  435 . For example, a bladder (not shown) may be disposed within handle  406  adjacent means for interrupting  425  and/or means for flushing  435 . In this embodiment, a physician may compress one or more external regions of handle  406 , which in turn compresses the bladder adjacent to means for interrupting  425  and/or means for flushing  435 . This, in turn, causes compression of a corresponding section of tubing  22 .  
      In an embodiment, means for interrupting and means for flushing may be positioned within a handle of the surgical cutting instrument. Actuation of these components may be accomplished electronically, e.g., by pressing a button disposed on the handle. In an embodiment, the components may be actuated mechanically.  
      In the device described in  FIG. 9 , means for interrupting  425  and/or means for flushing  435  may comprise one or more rollers that are configured to compress tubing  22 , as described generally hereinabove with respect to  FIGS. 5-8 . In this embodiment, when actuation means  419  is actuated, a microprocessor (not shown) may provide instructions to one or more components, such as linkages, to cause the roller or rollers to compress tubing  22  as desired locations.  
      In yet a further alternative embodiment, actuation of means for interrupting  425  and means for flushing  435  may be achieved using a foot pedal (not shown). In this embodiment, the foot pedal may be coupled to a microprocessor that is programmed to actuate means for interrupting  425  and/or means for flushing  435 , for example, when the foot pedal is depressed one or more times. Referring now to  FIG. 10 , a further alternative embodiment of the present invention is described. In  FIG. 10 , apparatus  400 ′ is similar to apparatus  400  of  FIG. 9 , with pertinent exceptions noted hereinbelow. Apparatus  400 ′ comprises irrigation supply line  439  having proximal and distal ends. The proximal end of the irrigation supply line  439  is coupled to an irrigation source (not shown) and the distal end is coupled to means for flushing  435 ′. In the embodiment of  FIG. 10 , means for flushing  435 ′ preferably comprises a one-way valve electronically coupled to actuation means  419 , although other mechanical or electrical valves may be employed.  
      In operation, when an obstruction is detected in cutting edge  12 , means for interrupting  425 ′ is actuated to interrupt aspiration by compressing tubing section  22   b ′, for example, using any of the techniques described hereinabove. In a next step, means for flushing  435 ′ is actuated. Specifically, in a preferred embodiment, an electronic signal is sent to means for interrupting  435 ′ to cause a one-way valve to open. The opening of the one-way valve permits fluid in irrigation line  439  to be advanced through the valve and towards tubing section  22   c ′. Irrigation fluid introduced through tubing section  22   c ′ then imposes pressure upon cutting edge  12  to flush tissue obstructions away from the cutting instrument.  
      As will be apparent to one skilled in the art, the pressure of the irrigation fluid introduced into tubing  22   c ′ may be adjusted to facilitate removal of the obstruction. Further, means for interrupting  425 ′ and means for flushing  435 ′ may be actuated in a pre-programmed sequence using a microprocessor, as described hereinabove with respect to  FIG. 9 , or may be actuated in sequence mechanically using a multi-position switch, as described hereinabove.  
      It should be noted that, in the embodiment of  FIG. 10 , three tubing sections  22   a ′- 22   c ′ are employed. Tubing section  22   a ′ is sealingly coupled to tubing section  22   b ′, while tubing section  22   b ′ is sealingly coupled to tubing section  22   c ′. In this embodiment, tubing section  22   b ′ may comprises a more flexible material than sections  22   a ′ and  22   c ′ to facilitate compression of section  22   b′.    
      It will be apparent to one skilled in the art that illustrative components of apparatus  400  may be interchanged with components of apparatus  400 ′, and vice versa. For example, apparatus  400  of  FIG. 9  may comprise three separate tubing sections, as depicted in  FIG. 10 . Further, means for interrupting  425  of  FIG. 9  may be disposed circumferentially about aspiration tubing, as depicted in  FIG. 10 , and so forth.  
      It will also be apparent to one skilled in the art that tissue obstructions may be detected by the physician, who then actuates the apparatus described hereinabove, or alternatively, the tissue obstructions may be detected using one or more sensors coupled to the cutting instrument. In the latter case, the sensors may detect a tissue obstruction directly, or may determine that an obstruction is present based on a reduction in flow likely to be associated with an obstruction. Once an obstruction is suspected, the sensors may relay a signal to automatically actuate the means for interrupting and/or means for flushing to facilitate removal of the obstruction with little or no physician intervention.  
      In an embodiment, the apparatus may include a disposable shaver blade set configured to be used with a conventional mechanical shaver handle. The disposable shaver blade set may include an inner cutting member and an outer sheath member. The inner cutting member may include an elongated shaft having a lumen disposed therein. The outer sheath member form a lumen disposed therein, which is configured to receive the elongated shaft of the inner cutting member. A disposable shaver blade set may be coupled to a distal region of the mechanical shaver handle such that a motor of the mechanical shaver handle drives the inner cutting member to debride bodily tissue.  
      Referring now to  FIG. 11 , two components of a disposable shaver blade set  510  are described. The disposable shaver blade set  510  has an inner cutting member  512  and an outer sheath member  514 . Inner cutting member  512  has a proximal end  518 , a distal end  516  and an elongated hollow shaft  520  extending therebetween. The distal end  516  has a distal opening  522  and a cutting edge  524 , while the proximal end  518  has proximal body  526 , a shaped clutch  528  and a proximal opening  530 .  
      The shaped clutch  528  is configured to be coupled to a motor of a mechanical shaver handle (not shown). The motor drives the inner cutting member to permit tissue to be debrided, as described in greater detail hereinbelow.  
      Proximal opening  530  of inner cutting member  512  is in fluid communication with the inside of elongated hollow shaft  520  and distal opening  522 . During normal operation, fluid typically is suctioned into distal opening  522 , then through lumen  523  in elongated shaft  520 , through proximal opening  530 , and through a lumen in the mechanical shaver handle.  
      Outer sheath member  514  has a proximal end  534 , a distal end  532 , and a hollow shaft  536  extending therebetween. The inner cutting member  512  is configured to be inserted into lumen  539  of outer shaft member  514 , as indicated by the arrow of  FIG. 11 . The assembled components are depicted in  FIG. 12 .  
      The proximal end  534  of outer sheath member  514  has an anchoring means  542 , which is configured to attach outer sheath member  514  to the mechanical shaver handle. The proximal end  534  has an optional attachment means  544  for attaching the outer sheath member  514  to an access cannula (not shown).  
      In an embodiment, rotation of the inner cutting member during use may be driven via the mechanical shaver handle. Debrided tissue is aspirated through the lumen of the inner cutting member. When an obstruction is present in the disposable shaver set, a means for interrupting may be actuated so as to interrupt suction at the distal cutting edge of the inner cutting member. The distal end  532  of outer sheath member  514  has a distal opening  538  and a part-off edge  540 , as shown in  FIG. 11 . Part-off edge  540  is configured to sever tissue drawn into the distal opening  538  when the cutting edge  524  of the inner cutting member  512  is rotating within the distal opening. In particular, a distal region  516  of the inner cutting member  512  is seated against distal region  532  of the outer sheath member  514 , such that the cutting edge  524  is aligned for opposition to the part-off edge  540 .  
      A common problem associated with the use of surgical cutting instruments during arthroscopic procedures is the tendency of cut tissue to become clogged in the vicinity of distal opening  538  and cutting edge  524  of the instrument. In accordance with one aspect of the present invention, apparatus and methods described hereinbelow are provided to quickly and efficiently expel clogged tissue from distal opening  538  without the need to remove shaver blade set  510  from the mechanical shaver handle or the operative site.  
      In an embodiment, both the inner cutting member and the outer sheath member may include at least one side port. The side ports of the inner cutting member and the outer sheath member may at least partially overlap. A fluid supply line coupled to an irrigation source, may be provided in fluid communication with the side ports of the inner cutting member and outer sheath member. Referring now to  FIGS. 13-15 , another embodiment of the present invention is described wherein the same or similar reference numbers refer to the same or similar structure. In  FIG. 13 , an inner cutting member  512 ′ is similar to inner cutting member  512  of  FIGS. 11-12 , with a main difference being that a side port  546  is disposed in a lateral surface of the elongated shaft  520 ′. Similarly, outer sheath member  514 ′ has been modified by adding side port  548  along a lateral surface of shaft  536 ′. It should be noted that both side ports  546  and  548  are in fluid communication with lumens  523 ′ and  539 ′ of inner cutting member  512 ′ and outer sheath member  514 ′, respectively.  
      Referring now to  FIG. 14A , apparatus  550  is configured for use with disposable shaver blade set  510 ′ of  FIG. 13  to facilitate removal of obstructions from the distal opening or cutting edge during a surgical procedure. Apparatus  550  comprises a means for flushing fluid in a distal direction, as described in greater detail with respect to  FIG. 15  below.  
      In  FIG. 14A , a side view of apparatus  550  is shown. Apparatus  550  includes a housing  552  having a proximal end  556 , a distal end  554 , a fluid supply line  560  and an actuation means  558 . In  FIG. 14B , a front view of apparatus  550  reveals that the apparatus has a through port  562  disposed in a lateral surface of a distal wall  554 . Through port  562  forms a conduit that extends proximally through the housing  552 . Further, a through port  562  is in fluid communication with a bore  565  formed at the proximal end  556  as shown in  FIG. 15  hereinbelow.  
      Referring now to  FIG. 15 , a first application of the present invention is described. In  FIG. 15 , disposable shaver set  510 ′ of  FIG. 13  is shown used in conjunction with apparatus  550  of  FIGS. 14A-14B .  
      Housing  552  of apparatus  550  has a securing attachment  564 , which is disposed near the proximal end  556  of the housing. As shown in  FIG. 15 , the securing attachment  564  is configured to be coupled to the attachment means  544 ′ of the outer sheath member  514 ′. The securing attachment  564  and the attachment means  544 ′ may be coupled together in any suitable manner, for example, using a snap-lock engagement or by rotatingly threading attachment means  544 ′ into engagement with means for securing  564 . Once these components are coupled together, longitudinal movement of the outer sheath member  514 ′ with respect to housing  552  is substantially prohibited.  
      The housing  552  also includes a proximal sealing ring  568  and a distal sealing rings  566 . The proximal and distal sealing rings  568 ,  566  are configured to provide a fluid tight seal around the exterior surface of the shaft  536 ′ of the outer sheath member  514 ′. Proximal and distal sealing rings  568  and  566  prohibit fluid movement within the port  562  for purposes described hereinafter.  
      Referring still to  FIG. 15 , the housing  552  also has a reservoir  580 . The reservoir  580  is surrounded by an actuation means  558 , a first one-way valve  582 , a second one-way valve  584 , and a wall  567  of the housing  552 , as depicted in  FIG. 15 .  
      The actuation means  558  is attached to the housing  552  in such a manner that it forms a bulb-shaped member, as depicted in  FIG. 15 . Actuation means  558  may be manufactured using a suitable biocompatible compound that allows the actuation means to be compressed in an inward direction when a force is applied, and then return to its original, non-compressed state (shown in  FIG. 15 ) when the compressive force is removed.  
      Irrigation fluid from the fluid supply line may be distally injected into the lumen of the inner cutting member via the side ports of the inner cutting member and outer sheath member. The irrigation fluid may be injected into the side ports at a location distal to the means for interrupting. The irrigation fluid introduced into the lumen of the inner cutting member flows distally towards the end of the disposable shaver set, clearing the obstructing material from the cutting edge of the surgical instrument. In order to facilitate the introduction of irrigation fluid into the side ports of the inner cutting member and outer sheath member, a suitable housing may be employed. The housing preferably includes a fluid reservoir configured to temporarily check fluid flow from the supply line. Preferably, a first one-way valve is provided to permit fluid from the supply line to enter the reservoir of the housing. A second one-way valve is provided that contains the fluid in the reservoir until an actuation means is actuated, thereby urging fluid distally into the lumen of the inner cutting member. The apparatus  550  also includes a delivery channel  570  having proximal and distal regions. Fluid supply line  560  is coupled to the proximal region of a delivery channel  570 , as shown in  FIG. 15 . The first one-way valve  582  separates the distal region of delivery channel  570  from reservoir  580  and the second one-way valve  584  separates reservoir  580  from through port  562  of housing  50 , as shown in  FIG. 15   
      In an embodiment of a method of operation, the fluid supply line  560  provides irrigation fluid to the delivery channel  570 . The first one-way valve  582  permits fluid flow in a distal direction, i.e., from delivery channel  570  into the reservoir  580 . Irrigation fluid is collected in the reservoir  580 , and cannot flow in a proximal direction back into the delivery channel  570 .  
      When actuation means  558  is compressed, e.g., manually, irrigation fluid in the reservoir  580  is urged in a distal direction through the second one-way valve  584 . Irrigation fluid flows distally through the second one-way valve  584  into through port  562 , but cannot flow in a proximal direction back into the reservoir  580 . Irrigation fluid is injected into disposable shaver set  510 ′ via side ports  548  and  546  of the outer sheath member  514 ′ and inner cutting member  512 ′, respectively. As shown in  FIG. 15 , the side ports  548  and  546  at least partially overlap to permit the introduction of irrigation fluid into lumen  523 ′ of inner cutting member  512 ′ of  FIG. 13 .  
      It should be noted that irrigation fluid flowing distally through the second one-way valve  584  is urged into lumen  523 ′ in part because the fluid cannot flow proximally past proximal sealing ring  568  and cannot flow distally beyond distal sealing ring  566 . Therefore, fluid flowing from the reservoir  570  into through port  562  of the housing  552  is urged into lumen  523 ′ via side ports  546  and  548 .  
      In accordance with one aspect of the present invention, irrigation fluid that is channeled into lumen  523 ′ is urged in a distal direction, i.e., towards the opening  538 ′ and the cutting edge  524 ′, because a means for interrupting (not shown in  FIGS. 13-15 ) is previously actuated. The means for interrupting inhibits aspiration flow in lumen  523 ′ at a location proximal to the side ports  546  and  548 .  
      Specifically, during operation of disposable shaver set  510 ′, when a physician suspects that an obstruction is present in the vicinity of distal opening  538 ′ and/or cutting edge  524 ′, the means for interrupting is actuated. The means for interrupting interrupts the provision of aspiration to distal opening  538 ′ and cutting edge  524 ′ by blocking aspiration flow through lumen  523 ′ at a location proximal to the means for flushing.  
      The means for interrupting is not shown in  FIGS. 13-15  for illustrative purposes only. However, several different means for interrupting may be employed to inhibit the provision of aspiration within lumen  523 ′ such as those described herein and in U.S. patent application Ser. No. 10/782,489, filed February  18  which is incorporated herein by reference in its entirety. The means for interrupting may be disposed in the mechanical shaver handle itself, or coupled to aspiration tubing extending between the suction source and the handle.  
      Alternatively, a means for interrupting that may be used in the embodiment of  FIGS. 13-15  is described fully with respect to  FIGS. 18-22  hereinbelow. Specifically, means for interrupting of  FIGS. 8-12  may be employed to inhibit aspiration flow within the mechanical shaver handle.  
      Further, it will be apparent to one skilled in the art that means for interrupting also may be disposed in, or coupled to, the apparatus  550  of  FIGS. 14-15 . In keeping with the spirit of the present invention, any number of means for interrupting may be employed to interrupt the provision of aspiration through lumen  523 ′, the means for interrupting being disposed proximal to the means for flushing.  
      Referring still to  FIG. 15 , and with the means for interrupting actuated, the actuation of actuation means  558  applies pressure to irrigation fluid in reservoir  580 , thereby causing fluid from the reservoir  580  to flow distally in lumen  523 ′. The distally flowing fluid flushes clogged tissue away from distal opening  538 ′ and the cutting edge  524 ′ of the surgical instrument. Once the compressive force imposed upon actuation means  558  is released, aspiration flow may be restored throughout lumen  523 ′. The previously-clogged tissue then may be introduced back into cutting edge  524 ′, reduced in size, and then effectively aspirated through lumen  523 ′.  
      It should be noted that once the compressive force imposed on actuation means  558  is removed, fluid from supply line  560  passes through the first one-way valve  582  and replenishes the fluid supply in the reservoir  580 . In this manner, actuation means  558  may be repeatably depressed, as needed, to provide multiple flushes in order to improve the likelihood that clogged tissue is removed.  
      Advantageously, obstructing tissue may be removed from the disposable shaver set using actuation means  558  without having to remove the cutting instrument from the surgical site. Also, the surgeon is not expected to have to replace the disposable shaver set with a different instrument, thereby saving time and money.  
      Referring now to  FIGS. 16A-16C , various actuation means for actuating the means for flushing of  FIGS. 14-15  are described. In  FIG. 16A , actuation means  558  is the same as the actuation means described in  FIGS. 14-15 , and is provided for illustrative purposes only.  
      In  FIG. 16B , alternative actuation means  558 ′ is coupled to housing  550 ′, and further coupled to an electrical supply line  586 . Preferably, the embodiment of  FIG. 16B  comprises similar sealing rings, one-way valves and means for securing, as was described in detail in  FIG. 15  and those features are expressly incorporated here. However, in the embodiment of  FIG. 16B , an electro-mechanical actuator (not shown), such as a piston, is used to inject fluid from supply line  560  into lumen  538 ′ and towards the cutting edge  524 ′. Specifically, depressing actuation means  558 ′ activates the electro-mechanical actuator, which is powered by electrical supply line  586 .  
      In the embodiment of  FIG. 16C , the actuation means employed (not shown) is similar to  FIG. 16B , but the electro-mechanical actuator of  FIG. 16B  may be activated using a foot pedal, an actuator mounted on the mechanical shaver handle, or an actuator mounted outside the sterile field. Such actuation means are well known in the art and are often used to trigger powered equipment in the operative field.  
      Referring now to  FIGS. 17A-17B , an alternative means for flushing  590  is described for clearing obstructions from surgical cutting instruments. In  FIG. 17A , means for flushing  590  is integrated into the outer sheath member  514 ′ of disposable shaver blade set  510 ′.  
      In the embodiment of  FIGS. 17A-17B , inner cutting member  512 ′ and outer sheath member  514 ′ of  FIGS. 13-14  are employed. Inner cutting member  512 ′ comprises elongated shaft  520 ′ and lumen  523 ′ disposed therein. Further, as described above, side port  546  is formed in a lateral surface of inner cutting member  512 ′, as shown in  FIG. 17B . Similarly, outer sheath member  514 ′ comprises an elongated shaft having side port  548  disposed therein, and lumen  539 ′ for accommodating inner cutting member  512 ′.  
      In an alternative embodiment, the means for flushing includes a reservoir coupled directly to an exterior surface of the disposable shaver set. In this embodiment, mounting means are provided on the outer sheath member, and a bulb-shaped member is coupled to the mounting means. A fluid reservoir is formed between the bulb-shaped member and the outer sheath member. In  FIGS. 17A-17B , means for flushing  590  has actuation means  592 , which preferably is attached to mounting means  588  in such a manner that it forms a bulb-shaped member, as depicted in  FIG. 17B . Actuation means  592  and mounting means  588  enclose a fluid reservoir  594 .  
      Actuation means  592  may be manufactured using a suitable biocompatible compound that allows the actuation means to be compressed in an inward direction when a force is applied, and then return to its original, non-compressed state (depicted in  FIG. 17B ) when the compressive force is removed.  
      When an obstruction is detected, a means for interrupting, which is located proximal to the fluid reservoir, is actuated to interrupt the provision of suction to the distal cutting edge of the inner cutting member. Then, in a next step, the means for flushing is actuated by depressing the bulb-shaped member to cause fluid from the reservoir to be injected into the side ports of the inner cutting member and outer sheath member. Injected fluid then flows distally within the lumen of the inner cutting member towards the cutting edge to facilitate removal of clogged tissue. In an embodiment, a method of operation when an obstruction is detected in the cutting instrument, may include actuating the means for interrupting (not shown in  FIGS. 17A-17B ). As described below with respect to  FIGS. 18-22 , the means for interrupting is disposed proximal to the means for flushing, and inhibits aspiration flow to a distal section of lumen  523 ′.  
      After the means for interrupting is actuated, means for flushing  590  may be actuated. Specifically, compression of actuation means  592  forces fluid contained in fluid reservoir  594  into lumen  523 ′ via side ports  548  and  546 . Fluid injected into lumen  523 ′ is urged in a distal direction to clear clogged tissue from opening  538 ′. Of course, fluid is urged in a distal direction because the means for interrupting prevents irrigation fluid from flowing proximally towards the suction source.  
      Advantageously, the fluid reservoir may be refilled simply by relieving the compressive force applied to the bulb-shaped member. Specifically, a vacuum force causes fluid in the lumen to return to the fluid reservoir, via the side ports, once compression is removed. This allows repeated compression of the bulb-shaped member to repeatedly flush the cutting edge of the instrument. When compression of actuation means  592  is relieved, then a vacuum force causes fluid from lumen  523 ′ to be brought back into fluid reservoir  594  via side ports  546  and  548 . In this manner, a physician may repeatedly compress and release actuation means  592  to repeatedly flush particulate matter from distal opening  538 ′.  
      It will be apparent to one skilled in the art that, in the embodiments of  FIGS. 13-15  and  FIGS. 17A-17B , each side port  546  and  548  may comprise multiple openings or one single opening. Further, the configurations of the openings may be varied to achieve the objectives of the present invention.  
      Referring now to  FIGS. 18A-18C , a further alternative embodiment of the present invention is described. In this embodiment, apparatus  100  comprises mechanical shaver handle  102 , means for interrupting  110  and means for flushing  150 .  
      Mechanical shaver handle  102  preferably is similar to a conventional handle used in surgical cutting instruments, except as noted below. A conventional disposable shaver set, such as disposable shaver set  510  of  FIGS. 11-12 , may be coupled to a distal region of handle  102  to debride tissue, as generally set forth above. As will be apparent to one skilled in the art, a motor (not shown) is incorporated into handle  102  to drive inner cutting member  512  of  FIG. 11 . Further, a suction source (not shown) is coupled to a proximal region of handle  102 , such that the suction source is in fluid communication with proximal lumen section  116  of handle  102 , as described in further detail hereinbelow.  
      In any of the embodiments described herein, the means for interrupting may include a rotating valve member coupled to the mechanical shaver handle. In operation, rotation of an actuation means coupled to the rotating valve member causes the valve member to block aspiration flow through the lumen of the mechanical shaver handle. With fluid flow interrupted, the means for flushing injects fluid into the lumen at a location distal to the means for interrupting, thereby causing injected fluid to flow distally towards the distal cutting edge of the instrument.  
      In the embodiment of  FIGS. 18A-18C , means for interrupting  110  comprises rotating valve member  114 , rotational joint  113  and actuation means  112 . Joint  113  is coupled to an interior section of mechanical shaver handle  102  such that actuation means  112  and rotating valve member  114  can rotate about a pivot point. For example, rotational joint  113  may comprise a laterally-extending shaft disposed through a complementary bore (not shown) formed in an upper surface of handle  102 . The laterally-extending shaft is configured for circumferential rotation within the bore, thereby permitting rotational movement of rotating valve member  114  and actuation means  112 .  
      As will be shown in greater detail below, rotating valve member  114  is disposed for rotation within fluid cut-off chamber  118 , which is situated between proximal lumen section  116  and distal lumen section  118  of handle  102 .  
      Referring still to  FIGS. 18A-18C , means for flushing  150  comprises actuation means  152 , fluid reservoir  154  and means for refilling  158 . Actuation means  152  may comprise any suitable compliant biocompatible membrane that may be deformed as shown in  FIG. 18C  below. In a preferred embodiment, means for refilling  158  comprises a spring disposed within the biocompatible membrane of actuation means  152 . The spring is configured to return actuation means  152  to the position depicted in  FIG. 18A , as described in further detail below.  
      Means for flushing  150  preferably further comprises anchor bracket  156  and means for securing  160 . Mechanical shaver handle  102  preferably comprises anchor pocket  122  disposed in a lateral surface of the handle, which is configured to receive anchor bracket  156 , as depicted in  FIG. 18A . In one embodiment, means for securing  160  comprises at least two bolts  160  that are configured to be received by bores formed in anchor bracket  156  and handle  102 . Accordingly, the bolts secure means for flushing  150  to handle  102 , as shown in  FIG. 18C .  
      It should be noted that in  FIGS. 18A-18B , anchor bracket  156  and means for securing  160  are not secured to mechanical shaver handle  102 , while in  FIG. 18C , the components are secured together. This is for illustrative purposes only. During normal operation, described below, means for flushing  150  would be secured to handle  102  as shown in  FIG. 18C . Further, as will be apparent to one skilled in the art, numerous other means for securing may be employed to secure means for flushing  150  to handle  102 .  
      Mechanical shaver handle  102  further comprises at least one side port  103 , which is formed in a lateral surface of the handle. Side port  103  is disposed for fluid communication with reservoir  154  of means for flushing  150 , as shown in  FIGS. 18A-18C .  
      A preferred method of using apparatus  100  of  FIGS. 18A-18C  will now be described. In a first step, shown in  FIG. 18A , rotating valve member  114  is provided in an open position. When suction is applied by the suction source coupled to the proximal end of the handle, aspiration is provided throughout proximal and distal lumen sections  116  and  120 , thereby providing aspiration to cutting edge  524  and distal opening  538  of disposable shaver set  510  to remove cut tissue.  
      If a physician detects that cut tissue has clogged distal opening  538  or cutting edge  524 , the physician first rotates means for actuating  112  in a counter-clockwise direction. This causes rotating valve member  114  to be advanced counter-clockwise via rotational joint  113 . Assuming a sufficient degree of rotation is achieved, then rotating valve member  114  is transformed to a closed position, as depicted in  FIG. 18B . In the closed position, valve member  114  prohibits aspiration of fluid distal to the valve member. It should be noted that, at this time, aspiration may still occur in proximal lumen section  116  because the suction source need not be turned off each time an obstruction is detected. Rather, the actuation of means for interrupting  110  blocks the flow of aspiration through distal lumen section  120  to the surgical site.  
      In a next step, depicted in  FIG. 18C , means for flushing  150  is actuated. Actuation may be achieved by compressing actuation means  152  to force fluid contained in reservoir  154  in a distal direction through side port  103 , as indicated by the arrows in  FIG. 18C . Preferably, the complaint membrane of actuation means  152  substantially conforms to the compressive forces applied.  
      Fluid that is injected distally through side port  103  flows distally through distal lumen section  120 . It should be noted that the injected fluid cannot flow proximally since rotating valve member  114  blocks flow through chamber  118 . In accordance with one aspect of the present invention, fluid injected into distal lumen section  120  flows distally towards the cutting edge of the surgical instrument to facilitate removal of clogged tissue.  
      Once flushing occurs, a physician may relieve the compressive force imposed upon actuation means  152 . Means for refilling  158 , such as a spring, causes the membrane of actuation means  152  to return to the position depicted in  FIG. 18B . When actuation means  152  returns to its expanded position of  FIG. 18B , a vacuum force causes reservoir  154  to be refilled with fluid from distal lumen section  120 . With reservoir  154  refilled, a physician may subsequently compress actuation means  152  to repeat flushing of the cutting edge, and the process may be repeated as necessary until clogged tissue is expelled.  
      Referring now to  FIGS. 19-20 , a further alternative embodiment of the present invention is described. In this embodiment, apparatus  200  comprises mechanical shaver handle  102 , means for interrupting  110 , fluid supply means  204  and means for flushing  211 . Mechanical shaver handle  102  and means for interrupting  110  preferably are provided as described in  FIGS. 18A-18C  hereinabove, except as noted below.  
      In  FIGS. 19-20 , apparatus  200  comprises fluid supply line  204  having proximal end  208  and distal end  206 . Proximal end  208  is coupled to means for flushing  211 , as shown in  FIG. 19B .  
      Means for flushing  211  is in the general form of a foot pedal and comprises base plate  217 , deflection plate  212 , fluid reservoir  213  and membrane  219 , which is coupled between deflection plate  212  and base plate  217 . Base plate  217  is coupled to deflection plate  212  at pivot point  215 . As will be apparent to one skilled in the art, compression of deflection plate  212  in a direction towards base plate  217  forces fluid contained in reservoir  213  through fluid supply line  204  and into distal lumen section  120  of handle  102 .  
      Referring now to  FIG. 20 , distal end  206  of fluid supply line  204  is disposed for fluid communication with side port  103  of mechanical shaver handle  102 . Distal end  206  of fluid supply line  204  preferably is secured to fluid supply coupler  221 , as depicted in  FIG. 20 . Further, in a preferred embodiment, mechanical shaver handle  102  comprises anchor pocket  122 , which is configured to receive a distal section of fluid supply coupler  221 . Fluid supply coupler  221  preferably is secured to mechanical shaver handle  102  using attachment screws  224 , and this connection is sealed against fluid leaks by sealing ring  205 .  
      The operation of apparatus  200  is similar to the operation of apparatus  100  of  FIGS. 18A-18C , except as noted below. During normal operation, means for interrupting  110  is provided in the open position depicted in  FIG. 20  to permit aspiration throughout proximal and distal lumen sections  116  and  120 . When a possible tissue obstruction is detected in the vicinity of cutting edge  24 , then actuation means  112  of means for interrupting  110  is actuated to cause rotating valve member  114  to block chamber  118 , as described in  FIG. 18B  above.  
      In a next step, a physician may actuate means for flushing  211 , e.g., by stepping on deflection plate  212  to compress fluid contained in reservoir  213 . The fluid contained in reservoir  113  then flows through fluid supply line  204  and into distal lumen section  120  via side port  103  of handle  102 . When rotating valve member  114  is in a closed position, as described in  FIG. 18C  hereinabove, then fluid injected into distal lumen section  120  is urged in a distal direction towards distal opening  538 . In this manner, fluid flushes clogged tissue away from cutting edge  524  and distal opening  538  of the cutting instrument. Further, as described hereinabove, means for flushing  211  may be repeatedly actuated, e.g., by compressing and releasing deflection plate  212 , to repeatedly flush the cutting edge and distal opening, thereby facilitating removal of clogged tissue.  
      Referring now to  FIGS. 21A-21B , a further alternative embodiment of the present invention is described. In this embodiment, apparatus  300  comprises mechanical shaver handle  102 , means for interrupting  110  and means for flushing  330 . Mechanical shaver handle  102  and means for interrupting  110  preferably are provided as described in  FIGS. 18A-18C  hereinabove, except as noted below.  
      In  FIGS. 21A-21B , means for flushing  330  comprises actuation means  332 , membrane  338 , and fluid reservoir  340  contained therein. Membrane  338  preferably is coupled between actuation means  332  and a lateral surface of mechanical shaver handle  102 , as depicted in  FIG. 21A . Reservoir  340  is in fluid communication with distal lumen section  120  of mechanical shaver handle  102  via side port  103 .  
      Means for flushing  330  further comprises means for securing  336  and pivot means  334 . Means for securing  336  may be in the form of a block member that is attached to shaver handle  102 , as shown in  FIG. 21A . Pivot means  334  couples means for securing  336  to actuation means  332  and allows rotational movement of actuation means  332  with respect to handle  102 .  
      The operation of apparatus  300  is similar to the operation of apparatus  100  of  FIGS. 18A-18C , except as noted below. During normal operation, means for interrupting  110  is provided in the open position depicted in  FIG. 18A  to permit aspiration throughout proximal and distal lumen sections  116  and  120 . When a physician detects a possible tissue obstruction near cutting edge  524 , then actuation means  112  of means for interrupting  110  is actuated to cause rotating valve member  114  to block chamber  118 , as depicted in  FIG. 21A .  
      In a next step, a physician may actuate means for flushing  330 , e.g., by manually compressing actuation means  332  towards handle  102 . Actuation means  332  pivots about pivot means  334  and urges fluid in reservoir  340  through side port  102  and into distal lumen section  120 , as depicted in  FIG. 21B . During compression, membrane  338  collapses to permit actuation means  332  to be deflected as far as possible.  
      As described hereinabove, when rotating valve member  114  is in a closed position, fluid injected into distal lumen section  120  is urged in a distal direction towards distal opening  538 . In this manner, fluid flushes clogged tissue away from cutting edge  524  and distal opening  538  of the cutting instrument.  
      Further, means for flushing  330  may be repeatedly actuated, e.g., by compressing and releasing actuation means  332 . Each time actuation means  332  is released, the actuation means pivots about pivot means  334  and returns to the position depicted in  FIG. 21A . During this time, reservoir  340  is refilled with fluid from distal lumen section  120 . In this manner, a physician may repeatedly flush the cutting edge and distal opening, thereby facilitating removal of clogged tissue.  
      Referring now to  FIGS. 22A-22C , yet a further alternative embodiment of the present invention is described. In this embodiment, apparatus  400  comprises mechanical shaver handle  102  and means for interrupting  110 ′. Means for interrupting  110 ′ also serves as a means for flushing, as will be described in greater detail hereinbelow.  
      Means for interrupting  110 ′ is similar to means for interrupting  110  of  FIGS. 8A-8C , and comprises actuation means  112 , rotational joint  113  and rotating valve member  114 . In this embodiment, fluid seal  170  is coupled to an outer edge of rotating valve member  114 , as depicted in  FIG. 22A . Fluid seal  170  may comprise any suitable compliant biocompatible material that sealingly engages curved interior  172  of chamber  118  in handle  102 , for purposes described hereinafter.  
      During normal operation, means for interrupting  110 ′ is provided in the open position depicted in  FIG. 22A  to permit aspiration throughout proximal and distal lumen sections  116  and  120 . When a physician detects a possible tissue obstruction in the vicinity of cutting edge  24 , then actuation means  112  is rotated counter-clockwise to cause rotating valve member  114  to block chamber  118 , as shown in  FIG. 22B . At this time, aspiration in distal lumen section  120  is halted.  
      In a next step, a physician may further rotate actuation means  112  counter-clockwise to cause valve member  114  to rotate counter-clockwise along curved interior  172  of handle  102 , as depicted in  FIG. 22C . As valve  114  is rotated counter-clockwise, fluid in distal lumen section  120  is flushed in a distal direction, i.e., towards distal opening  538  and cutting edge  524 . In this manner, fluid flushes clogged tissue away from the cutting edge and distal opening of disposable shaver set  10 .  
      If a physician needs to repeatedly flush the cutting edge of the instrument, then the physician may repeatedly rotate actuation means  112  clockwise and counter-clockwise to recreate the flushing effect provided by rotating valve member  114 .  
      If desired, curved interior  172  may be provided with a distal stop (not shown) to inhibit further distal movement of rotating valve member  114 . Such a distal stop would ensure that seal  170  does not relinquish its sealing engagement with curved interior  172 , thereby ensuring that flushed fluid does not travel proximally back into proximal lumen section  116 .  
      It will be apparent to one skilled in the art that certain illustrative components in one embodiment hereinabove may be interchanged with components of another embodiment to achieve the objectives of the present invention. For example, if a fluid reservoir is employed, the fluid reservoir may be any one of the designs described hereinabove with respect to  FIG. 15  and  FIGS. 17-21 .  
      Further, as will be apparent to one skilled in the art, the shape and size of the reservoir may be varied to improve the ability to remove tissue obstruction from the cutting edge of the instrument. Similarly, any of the actuation means described hereinabove may be designed such that the rate of compression is varied to improve removal of obstructions from the cutting edge.  
      Also, in the embodiment of  FIGS. 22A-22C , it will be apparent to one skilled in the art that the configurations of chamber  118 , rotating valve member  114  and other components may be optimized to provide a sufficient volume and pressure of fluid that is flushed in a distal direction to facilitate removal of obstructions.  
      It will also be apparent to one skilled in the art that tissue obstructions may be detected by the physician, who then actuates the apparatus described hereinabove, or alternatively, the tissue obstructions may be detected using one or more sensors coupled to the cutting instrument. In the latter case, the sensors may detect a tissue obstruction directly, or may determine that an obstruction is present based on a reduction in flow likely to be associated with an obstruction. Once an obstruction is suspected, the sensors may relay a signal to automatically actuate the means for interrupting and/or means for flushing to facilitate removal of the obstruction with little or no physician intervention.  
      Now referring to  FIG. 23 a  different embodiment  600  of the present invention is shown comprised of a standard tubular shaver attachment  602  and a shaver power handle  601 . In this view the disposable shaver attachment  602  is not yet connected to the handle, but would be by attaching the attachment&#39;s proximal end  608  to the handles distal end  616  as shown by the arrow.  
      The shaver attachment  602  is comprised of an outer tube  604  and an inner cutting tube  606  which is configured to slide into and rotate within the outer tube. Both the inner and outer tubes have distal openings  610  which are configured to draw tissue in and resect it. The proximal end  608  of the inner tube is configured with a suction port  612  which is in communication with the distal opening  610 .  
      Now turning to the shaver handle  601 , it is comprised of a handle body  614 , and distal end  616  and a proximal end  618 . The distal end contains a distal coupling  620  configured to receive and lock in the proximal end of the shaver attachment  608 . The proximal end contains a power line  630 , a suction lumen coupler  628  and an aspiration lumen coupler  626 . The aspiration lumen coupler  626  is configured to accept a gas line (not shown) which is attached to a pressurized gas source as is typically found in the operating room. As well the suction lumen coupler  628  is configured to accept a suction line (not shown) which is attached to a suction source as is typically found in the operating room. Finally the power line  630  is connected to a shaver controller (not shown) as is typically used in the operating room. Also on the shaver handle body  614  are a suction flow control actuator  622  and an aspiration flow actuator  624 .  
      When the shaver attachment  602  is attached to the shaver handle  601  and a suction source (not shown) to the suction lumen coupler  628 , with the suction flow actuator  622  in the on position, fluid and tissue is drawn into the distal opening  610  through the inner tube  606 , out of the proximal opening of the inner tube  612  and through the shaver handle to the suction lumen coupler  628 . When tissue is clogged in the distal opening  610  and cannot be resected cleanly, the surgeon can move the suction flow actuator to the interrupt or off position stopping the flow of fluid into the distal end of the shaver attachment, as has been described above. Then the surgeon can activate the aspiration flow actuator  624 , which opens a valve inside the shaver handle body  614  and connects the high pressure gas connected to the aspiration lumen coupler  626 . This pressurized gas forces the clogged tissue distally out of the shaver attachment without the need for the surgeon to remove the shaver from the operating sight. The aspiration flow actuator can be configured to allow a continuous flow of gas through the distal opening  610  while it is activated (by depressing it for example) or a predetermined short burst, which is repeated each time the actuator is activated. In one embodiment the aspiration flow actuator  624  is configured such that it can only be activated when the suction flow actuator  622  is in the off or flow interrupted position.  
      Now turning to  FIG. 24 , another embodiment of the current invention  700  is shown. This embodiment is identical to that shown in  FIG. 23  with the exception of the aspiration gas source. In this embodiment the aspiration lumen coupler  726  is attached to a small cylinder of compressed gas  732  via a gas lumen  734  rather than the gas source available in the operating room. This is a convenience to the surgeon as there is one less line connecting to the proximal end  718  of the shaver handle which allows more freedom of movement of the shaver.  
      Now turning to  FIG. 25 , another embodiment of the current invention  800  is shown. This embodiment is identical to that shown in  FIG. 24  with the addition of a gas pressure regulator  836 . In this embodiment a gas pressure regulator  836  is located between the gas lumen  834  and the gas cylinder  832 . The pressure regulator  836  has an adjustment valve  838  which allows the surgeon to control the amount of pressure that is used to aspirate the clogged tissue. With the invention such as that shown in  FIG. 23  connected to a gas source in the operating room, there would also be a pressure regulator associated with that gas source located in the operating room which would allow the surgeon to control the aspiration pressure. In the embodiment shown in  FIG. 25  with a self-contained gas cylinder the addition of a pressure regulator on the shaver handle allows the surgeon to maintain the same control of the aspiration pressure without the addition of an additional line on the proximal end  818  of the shaver handle.  
      It will be noted that the type of gas used for aspiration can be any of a number of gases already in common use in the operating room such as but not limited to compressed air, carbon dioxide and nitrogen.  
      Another embodiment of the current invention  900  is shown in  FIG. 26 . In this embodiment the gas cylinder  932 , is integrated into the shaver handle  914  rather than being attached to the side. The gas cylinder is connected to the handle through the cylinder coupler  940  rather than the gas lumen. This embodiment can also have an optional pressure regulator (not shown) as discussed in  FIG. 25 . As was discussed with the embodiments shown in  FIGS. 24 and 25 , this embodiment has the previous advantages of one less proximal line as well as being contained in a similar size and shape as currently available tissue shaving systems.  
       FIG. 27  shows a portion of the cross-section of the shaver handle  1002  of the current invention  1000 . Within the shaver handle  1002  are a distal suction/irrigation lumen  1004  and proximal suction/irrigation lumen  1006 . The suction flow control actuator  1008  is attached to the suction flow interrupt means  1010  which is shown in the flow interrupt position. In this position flow from the distal suction lumen  1004  to the proximal lumen  1006  is prevented. Also shown are the aspiration flow actuator  1012  which is connected to the aspiration opening means  1016  via connection means  1018  (shown as dashed lines). When the aspiration flow means is activated the opening means  1016  allows pressurized gas to pass through the aspiration lumen  1014  and into the distal suction lumen  1004 . The suction interrupt means  1010  contains this pressurized flow and forces it distally towards the clogged tissue in the shaver tip (not shown) forcing the tissue out and unclogging the tip.  
      The aspiration flow actuator  1012  shown is an electrical switch which operates the aspiration opening means  1016  which is a mechanical valve. It should be obvious to those practiced in the art that these two parts can be combined into a single mechanical valve which would allow pressurized gas to flow into the distal suction lumen.  
      Although the previously described embodiments all had mechanical tissue resecting distal ends (commonly referred to as shavers), the current invention is equally as beneficial when used with basic suction apparatus that does not have mechanical cutting tips. Basic suction tips are used in most surgery to keep blood or other body fluids or irrigation fluid from accumulating at the operative site. These devices are nominally comprised of a long tube with a distal opening that is placed at the operating site through which excess fluid is removed. Just as with the mechanical cutting tips basic suction devices are attached to a standard vacuum line that is already part of the operating room equipment. Also, just as with the mechanical cutting tips, basic suction device often clog when a piece of debris or tissue that is larger than the distal opening becomes lodged in said distal opening.  
       FIG. 28  shows yet another embodiment of the current invention  1100  used for basic surgical fluid removal. The device has a suction tube  1102  and a handle  1104 . The distal end  1106  of the suction tube  1102  has an opening  1110  into which fluid is drawn. The proximal end  11011  of the handle  1104  has a suction lumen coupler  1114  as well as an aspiration coupler  1112 . Both couplers can be selectably in communication with the suction lumen inside the suction tube  1102  using the aspiration activator means  1116 .  
      In normal operation the suction lumen coupler  1114  which is attached to the vacuum source (not shown) already present in the operating room is in direct communication with the suction tube  1102  such that excess fluid can be drawn into the distal opening  1110  through the tube  1102  out the coupler  1114 . When tissue or debris is caught in the distal opening  1110  thereby preventing the flow of excess fluid, the operator can activate the aspiration activator means  1116  which will interrupt the suction flow between the suction lumen coupler  1114  and the distal tube  1102  and then connect the aspiration lumen coupler  1112  to the distal tube allowing the pressured gas source to force the caught tissue distally out of the opening  1110 . It will be obvious to those skilled in the art that these two functions of flow interruption followed by aspiration introduction can be combined in the single actuator as described or separated into two actuators. Further, it will also be obvious that these actions can be accomplished either with a direct mechanical valve or indirectly with an electrical switch that operates a mechanical valve. Finally, as was described in  FIGS. 24-26 , the aspiration means for this basic surgical fluid removal device can also be located in or on the handle  1104  of the device via a gas cylinder rather than from a vacuum source via the aspiration coupler  1112 .  
      Further Improvements  
      For the embodiments described below, term “fluid” as used herein generally refers to any suitable gas, such as nitrogen, or liquid although use of a gas may be beneficial when practicing some aspects of the presently described embodiments.  
      The tissue cutting device may include a flush lumen coupled to a source of pressurized gas. The source of pressurized gas may be provided in any suitable manner such as, by way of non-limiting example, a compressed gas bottle, a disposable can or a disposable gas cartridge. The flush lumen may be coupled to an aspiration lumen so that the gas may be used to clear the aspiration lumen of obstructing material.  
      A valve may be positioned along the flush lumen. The valve is normally in the closed position, and is opened upon actuation of a flush actuator by the user. When the user actuates the flush actuator, the valve opens to permit pressurized gas to pass through the flush lumen and into the aspiration lumen. The valve automatically closes after a short period of time so that the treated area, such as a joint, is not overly inflated. To this end, the valve may be open for less than 0.5 second, or less than 0.3 second. In other words, the volume of gas delivered may be less than 500 ml, or less than 300 ml. Of course, the gas may be delivered for a longer time or larger volumes of gas may be delivered without departing from various aspects of the presently described embodiments. The valve may be any suitable valve familiar to practitioners of ordinary skill in the art, such as a momentary pulsation valve. A gas holding chamber is positioned between the valve and the source of pressurized gas. The gas holding chamber may be expandable so that the chamber expands when filled with the pressurized gas. The chamber may be formed from any suitable materials such as a length of elastic tubing. The chamber may formed from elastic materials or rigid materials which deflect or otherwise displace to increase and decrease in volume as necessary. A flow restrictor may be positioned between the source of pressurized gas and the gas holding chamber. The flow restrictor may be 5-10 times smaller than the smallest dimension of the flush lumen so that the chamber discharges gas relatively quickly but is filled with gas from the source of pressurized gas relatively slowly. The flow restrictor may be, without limitation, any suitable art-recognized flow element including a fixed flow element. An advantage of using a fixed flow control element is that the source of pressurized gas may be a relatively inexpensive compressed gas container with little or no gas pressure regulation. Of course, various aspects of the presently described embodiments may be practiced using an adjustable regulator rather than the restrictor without departing from the invention.  
     EXAMPLES  
      The following will serve to illustrate, by way of one or more examples, systems and methods for inhibiting, reducing or otherwise disrupting prolactin signaling in pain neurons according to some embodiments. The examples below are non-limiting and are intended to be merely representative of various aspects and features of certain embodiments. Although methods and materials similar or equivalent to those described herein may be used in the application or testing of the present embodiments, suitable methods and materials are described below.  
     Example 1  
      A setup using a conventional high pressure (˜2000 psi plus) nitrogen tank and a regulator combined was used to simulate various pressure vessels of 45 psi and  
      higher. The output of the regulator was connected to a selected length of elastic polyurethane having calculable and modifiable volume to represent a capacitance element. The regulator acts a flow restrictor (that can be a fixed capillary or filter, or a adjustable regulator) that limits the refill speed of the tubing after it has been opened and depressurized momentarily to release the desired bolus of compressed gas for purging the shaver cannula Using flow restrictor controls the refill and re-pressurization of the tubing acting as a capacitor so as to produce a reservoir that is slow to refill but can be discharged rapidly by a push button momentatry-openable valve having considerably less flow restriction (5× or greater) than the fixed flow restrictor or regulator. The rapidly discharged nitrogen or other gas, of volume ranging typically from 50-200 ml exerts sufficient and sudden force to dislodge shaved debris from the tip of the cannula, without releasing excessive gas flow that would overfill the joint being treated, potentially distending and damaging the joint capsule or introducing such a large volume of air that the procedure is slowed by waiting to remove it through the aspiration tube. The air pulse deliver setup was connected to a Stryker shaver.  
      SUMMARIZED RESULTS: When tested with fragments of clay, elastomer, and human meniscus lodged the cutter-cannula, air pulses at 3040 psi lasting 100-200 ms successfully dislodged the simulated and actual debris clogs, expelling them from the tip of the cannula.  
      CONCLUSION: The presently described embodiments enable controlled delivery of bolus of purified, sterile inert gas such as nitrogen or other gas. The gas bolus is metered and delivered to the proximal end (housed within the shaver handle) to dislodge cartilage or meniscus or other shaved debris that, from time to time during the procedure, clogs the cutter end of the shaver cannula  
      This present embodiments cost-effectively and reliably provide a compact mechanism to meter compressed gas to deliver an short, abrupt bolus of valved gas, which is delivered very close to the proximal (within the shaver handle) end of the cannula. These properties provides advantages that enable reliable expulsion of clogging material from the distal end of a tissue shaver during the use thereof in a surgical procedure. 
      1). The gas bolus is still expanding as it enters the cannula, improving debris expulsion.     2). The gas bolus typically has essentially incompressible fluid in front of it out to the end of the cannula, so that the expulsive force and velocity is efficiently transferred to the debris at the cannula tip.     3). Valving the compressed gas from volume between the flow restrictor and valve (the pneumatic capacitor created by this invention) when communicated through a relatively large passageway, as is done in this invention, results in a brief, high-intensity gas bolus. 
 
 Performance of prior art renditions of the presently disclosed embodiments, on which the embodiments described herein are based has not been fully satisfactory for the purposes described above, such renditions consisting of manual compression of bladders or air compartments, by means of by hand manipulation squeezing a compartment so as to reduce its volume and expel air. 
   

      Creating a short, intense gas bolus without the benefit of explosive combustion or a moving piston, using only: a pressurized gas storage vessel; a gas “capacitor” (including a flow restrictor downstream from the gas storage vessel and downstream from the flow restrictor; either an expandable tube or other compartment, or a compartment of sufficient volume to allow expansion of a desired volume of gas to produce the bolus during momentary opening of a valve); and a momentary valve capable of rapidly providing a low restriction communication path to the proximal end of the shaver cannula (located in the drive handle of the shaver), thereby creating a low frequency sonic pulse and shock wave with that suddenly released gas bolus that can travel ahead of the gas/fluid flow to assist in dislodging debris from the shaver cannula tip.  
      The present invention has been described in connection with a preferred embodiment, however, it is understood that various modifications may be used without departing from the scope of the preceding description.  
      In this patent, certain U.S. patents, U.S. patent applications, and other materials (e.g., articles) have been incorporated by reference. The text of such U.S. patents, U.S. patent applications, and other materials is, however, only incorporated by reference to the extent that no conflict exists between such text and the other statements and drawings set forth herein. In the event of such conflict, then any such conflicting text in such incorporated by reference U.S. patents, U.S. patent applications, and other materials is specifically not incorporated by reference in this patent.  
      Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description to the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims. In addition, it is to be understood that features described herein independently may, in certain embodiments, be combined.