Abstract:
A suction wand for use during a surgical operation involving cutting of bone which yields bone debris, the wand comprising a suction conduit, a suction tip, a filter screen for retaining bone debris, and a carbon dioxide gas conduit for directing gas toward the suction tip to expel debris from the filter screen.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a non-provisional application of U.S. Ser. No. 61/259,111, filed Nov. 6, 2009, the entirety of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to a suction device for use in surgical procedures and more particularly to a surgical suction device for removing debris from a surgery site. 
       BACKGROUND OF THE INVENTION 
       [0003]    Suction devices are commonly used in a variety of medical applications to evacuate various fluids from a patient for a variety of purposes. For example, during surgery, blood and other body fluids are commonly removed to permit visual inspection of the surgical site and disposal of fluids. Suction wands may also provide for the production of positive pressure (usually air or water) to irrigate the surgical site. One such example is disclosed in Lester, U.S. Pat. No. 4,526,573 which shows a suction conduit from sucking debris away from the surgery site and an irrigation conduit for directing irrigation fluid to a surgery site. 
         [0004]    Prusmack US Publication No. 2007/0213667 discloses a suction irrigation cleaner configured to apply negative air pressure by connecting a first port to a suction source for removing debris and fluid from a surgical site. There is also an irrigation/positive pressure line to deliver positive air/vapor pressure by connecting a second port to a positive pressure source. The positive pressure fluid is used for irrigation and alternatively to unclog the device if tissue or clot is sucked into the device. The apparatus disclosed in Prusmack is not ideal because the tissue and clot can travel through device all the way to the valve mechanisms, potentially damaging the device. The irrigation function is complicated as it requires both turning of a stopcock and operation of a button to move the irrigation channel into the main flow path. Also, it does not inhibit larger potentially clogging debris from being sucked into the device beyond the point where the declogging function can be effective. 
         [0005]    Historically, suction wands (commonly referred to as “sucker tips”) were fabricated from metal and were reusable only after suitable cleaning and sterilization. With the recent advent of disposable surgical equipment, however, metal suction wands have been almost entirely replaced by cheaper, light weight, disposable suction wand systems fabricated from plastics. 
         [0006]    In orthopedic surgery, suction wands are vital for keeping the surgical site ‘dry’ improving visualization of tissues and for recovery of lost blood through means of ‘cell savers’ or devices that allow for the re-infusion of blood that may have oozed from the tissues of the surgical site. As shown in the Prusmack publication, a major obstacle to the optimal performance of sucker wands is the obstruction that occurs when bone bits and other debris are sucked into the suction line, effectively clogging the egress of fluids away from the surgical site and blocking the suction. A secondary problem has been the relatively high flow of air through the wand during the surgical procedure which leads to the potential deposition of airborne bacteria on the tip of the wand. And because the wand tip is moistened by the egress of fluid during suction, the wand tends to attract dust or debris which are then expelled to the surgical site when positive pressure is produced. Studies have shown that a sucker wand may be one of the highest sources of contamination during a surgical procedure. 
         [0007]    Therefore, there exists a need for a suction wand device that allows for the egress of fluids being removed from a surgical site, but still provides the operator the ability to conveniently unclog or unplug the device without the fear of contaminating the surgical site or damaging the device. The present invention also offers an efficient design that can be constructed with disposable plastic materials and easily disassembled for cleaning purposes. 
       SUMMARY OF THE INVENTION 
       [0008]    Briefly, therefore, the invention is directed to a suction wand comprising a handle, a suction conduit at least partially disposed in the handle and partially defining a suction path, and a suction tip at an end of the suction conduit. The suction path extends from the suction tip and through the handle, wherein the suction conduit is adapted to communicate with a vacuum source at a vacuum source end of the suction path remote from the suction tip. There is a filter screen for retaining bone debris, wherein the filter screen is disposed in the suction path and has a first side facing a tip direction and an opposite second side facing a vacuum source direction. There is a CO 2  gas conduit adapted for fluid communication with a gas source and at least partially disposed in the handle and partially defining a CO 2  path, the CO 2  gas conduit including a CO 2  gas main conduit section through which CO 2  gas flows and is directed into the suction conduit in a direction toward the tip such that the CO 2  gas passes through the filter screen from the second side facing in the vacuum direction, in the tip direction and out the first side of the filter screen facing in the tip direction, for expelling debris from the first side of the filter. There is also a CO 2  gas conduit valve operable between an open position in which CO 2  gas flows through the CO 2  gas conduit and into the suction conduit toward the suction tip and a closed position in which CO 2  gas does not flow into the suction conduit. 
         [0009]    In another aspect, the invention is directed to a suction wand for use in aspirating a surgical site during an orthopedic surgical operation which yields bone debris and generally comprises a handle and a suction conduit at least partially disposed in the handle and partially defining a suction path. A suction tip is at an end of the suction conduit. The suction path is adapted to communicate with a vacuum source at a vacuum source end of the suction path remote from the suction tip such that the suction path extends from the suction tip through the suction conduit to the vacuum source. A CO 2  gas conduit is adapted for fluid communication with a gas source and is at least partially disposed in the handle and partially defines a CO 2  path. A CO 2  gas conduit valve is operable between an open position in which CO 2  gas flows from the gas source through the CO 2  conduit and out the suction tip and a closed position in which CO 2  gas does not flow out of the suction tip. A filter screen is disposed in the suction path for retaining bone debris produced during the operation. The filter screen comprises a wire mesh including a set of parallel horizontal wires and a set of parallel vertical wires woven with the horizontal wires forming gaps between the wires. The gaps are sized and arranged to retain the bone debris on the screen when the wand is in a suction mode and permit a high blast of CO 2  to impinge upon the retained debris when the wand is in a CO 2  pressure mode to expel the debris from the screen. 
         [0010]    Other objects and features will be in part apparent and in part pointed out hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective of a suction wand of the present invention; 
           [0012]      FIG. 2A  is a cross-section of the suction wand taken through line  2 A- 2 A in  FIG. 1  with a handle removed and showing a valve of the wand in a closed position; 
           [0013]      FIG. 2B  is a cross section of the suction wand taken through line  2 B- 2 B in  FIG. 1  with the handle removed and showing the valve in an open position; 
           [0014]      FIG. 3  is an enlarged fragmentary cross section showing a suction conduit and a positive pressure conduit of the wand; 
           [0015]      FIG. 4  is an enlarged front view of a filter screen and cap of the suction wand; 
           [0016]      FIG. 5  is a schematic of a second embodiment of a suction wand; 
           [0017]      FIG. 6  is a schematic of a third embodiment of a suction wand; and 
           [0018]      FIG. 7  is a schematic of a fourth embodiment of a suction wand. 
       
    
    
       [0019]    Corresponding reference characters indicate corresponding parts throughout the drawings. 
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    Referring to the illustrated embodiment, and in particular  FIG. 1 , a suction wand for use during surgical operation to aspirate a surgical site is generally indicated at  11 . The suction wand comprises a handle  13  and a valve generally indicated at  15 , partially received in the handle for movement between an open and a closed position. An inflow tube  17  extends proximally from a proximal end of the handle  13  and is configured for attachment to a positive pressure source (not shown). The preferred positive pressure source is a CO 2  tank. An outflow tube  19 , below the inflow tube  17 , also extends proximally from the proximal end of the handle  13  and is configured for attachment to a negative pressure or suction source (not shown). 
         [0021]    A mount  21  ( FIGS. 2A-3 ) at a distal end of the handle  13  attaches a connector  23  and head portion  25  to the handle. The head portion  25  comprises a tubular member having a filter screen  27  disposed in an open, distal end or tip  29  of the head portion. A cap  31  retains the filter screen  27  in the tip  29 . The cap  31  can be removable to allow for the replacement of the filter screen  27  after use. As will be explained in greater detail below, when the valve  15  is in the closed position ( FIG. 2A ), activation of the suction source will generate a negative pressure gradient at the tip  29  of the head portion  25  for aspirating the surgical site when the wand  11  is used in a surgical procedure. Movement of an actuator  33  of the valve  15  moves the valve from the closed position to the open position ( FIG. 2B ), permitting fluid from the positive pressure source to escape through the tip  29  of the head portion  25 , past the filter screen  27  to expel any debris collected on the screen during aspiration. In the illustrated embodiment, the valve  15  is a ball valve. The handle  13 , mount  21 , connector  23 , head portion  25  and cap  31  are formed from plastic. However, the components can be made from other suitable materials such as stainless steel. 
         [0022]    Referring to  FIGS. 2A and 2B , a valve housing  35  is disposed in the handle  13  and seats the valve  15  for pivotal movement in the valve housing between the open and closed positions. The valve housing  35  includes a valve passage  37  that extends longitudinally in the valve housing and is partially defined by an opening  39  in the valve  15 . An inlet port  41  extends proximally from a proximal end of the valve housing  35  and is received in a distal end of the inflow tube  17  to fluidly connect the inflow tube to the valve passage  37 . A clamp  43  secures the inflow tube  17  around the inlet port  41 . An outlet port  45  extends distally from a distal end of the valve housing  35  and is received in a proximal end of a connection tube  47  to fluidly connect the connection tube to the valve passage  37 . A clamp  49  secures the connection tube  47  around the outlet port  45 . A distal end of the connection tube  47  is received in a first connection port  51  of the mount  21  to fluidly connect the connection tube to the mount. A second connection port  53  of the mount  21 , below the first connection port  51 , receives a distal end of the outflow tube  19  to fluidly connect the outflow tube to the mount. In the illustrated embodiment, the connection tube  47  and outflow tube  19  are secured in the connection ports  51 ,  53 , respectively, by adhesive. However, other suitable connection means such as clamps or by friction fit are within the scope of the present invention. Also, connectors other than clamps  43 ,  49  can be used. 
         [0023]    A first mount port  55  extends distally from a base  57  of the mount  21  and is received in a first connector port  59  of the connector  23  to fluidly connect the first mount port to the connector. A second mount port  61  of the mount  21 , below the first mount port  55 , also extends distally from the base  57  and is receive in a second connector port  63  of the connector  23  to fluidly connect the second mount port to the connector. 
         [0024]    The first connector port  59  extends distally through the connector  23  into the head portion  25 . The first mount port  55  and first connector port  59  broadly define a positive pressure conduit. The second connector port  63  opens into an interior space  65  in the connector  23  which opens into an interior space  67  in the head portion  25 . The second mount port  61 , second connector port  63 , connector interior space  65  and head portion interior space  67  broadly define a suction conduit. The suction conduit extends around the positive pressure conduit to the tip  29  of the head portion  25 . In this embodiment the longitudinal axes of the suction conduit and positive pressure conduit are coincident such that they are disposed on a common central axis CA ( FIG. 3 ). In the illustrated embodiment, an open end or tip  69  of the positive pressure conduit is spaced between about ¼ and about ¾ in., e.g., about ½ in., from the filter screen  27 , the reasons for which will be explained in greater detail below. It is seen there that in once sense the central axis of the positive pressure conduit, which here is the CO 2  gas conduit, and in particular the segment of the conduit which is the CO 2  gas conduit extension, is parallel with the central axis of the suction conduit, at least in the segment from the suction tip back to the handle. In another aspect it is seen that the central axis of the positive pressure conduit, which here is the CO 2  gas conduit, and in particular segment of the conduit which is the CO 2  gas conduit extension, is coincident with the central axis of the suction conduit, at least in the segment from the suction tip back to the handle. 
         [0025]    Referring to  FIG. 2A , a suction path is illustrated by a series of arrows. The suction path extends from a distal side of the filter screen  27  past the screen and tip  29  of the head portion  25 , through the suction conduit and into the outflow tube  19  to the suction source. When the suction wand  11  is used during a surgical procedure to aspirate a surgical site, the tip  29  of the head portion  25  is placed adjacent the surgical site and fluid and small particles permitted by the filter screen  27  are sucked from the surgical site along the suction path and can be collected remotely from the suction wand. To prevent fluid and debris from entering the positive pressure conduit a grate (not shown) can optionally be placed over the tip  69  of the positive pressure conduit. 
         [0026]    Conversely, a positive pressure path is illustrated by a series of arrows in  FIG. 2B . The positive pressure path extends from the positive pressure source, through the inflow tube  17 , into the inlet port  41  of the valve housing  35 , through the valve passage  37 , out the outlet port  45 , into the connection tube  57 , past the first connection port  51  of the mount  21 , through the first mount port  55 , into the first connector port  59  of the connector  23 , through the positive pressure conduit, out the tip  69  of the positive pressure conduit, partially through the interior space  67  of the head portion  25  and out the tip  29  of the head portion, past the filter screen  27 . The conduit segment between port  55  and tip  69  constitutes a CO 2  gas conduit extension which extends within an interior of the suction conduit for directing CO 2  gas directly at the suction tip. The CO 2  gas conduit extension in the preferred embodiment shown has a smaller inner diameter than the inner diameter of the CO 2  gas main conduit section, as manifest by tubes  47  and  17 . After the surgical site has been aspirated, the suction wand  11  can be operated in the positive pressure mode to expel any debris, such as larger bone chips in the case of orthopedic surgery, which may be caught in the filter screen  27 . Referring to  FIG. 3 , a distal end  71  of the first connector port  59  has an inner diameter ID of about 3/32 in. The inner diameter ID of the distal end  71  of the first connector port  59  can be between about 1/16 and about ⅛ in., the purpose of which will be explained in greater detail below. 
         [0027]    Referring to  FIG. 4 , the filter screen  27  comprises a woven mesh of parallel horizontal wires  73  and parallel vertical wires  75  forming open areas  77 . The wires  73 ,  75  may have a diameter D between about 0.01 in. and about 0.02 in. The wires  73 ,  75  can be spaced such that there are between about 12 to about 30 open areas  77  per square in. In the illustrated embodiment, there are about 20 open areas  77 . The open areas  77  can make up between about 49% and about 54% of the surface area of the filter screen  27 . The wires  73 ,  75  of the filter screen  27  are arranged such that the open areas  77  are sized and spaced to prevent debris from entering the suction conduit during aspiration of a surgical site yet still provide a sufficient opening to deliver a maximum output flow when the wand  11  is in the positive pressure delivery mode. In a preferred embodiment the wires  73 ,  75  are metal (i.e., steel, copper, brass, platinum). However, the wires  73 ,  75  can also be made from plastic, nylon or any other suitable material. 
         [0028]    In use, the inflow tube  75  is preferably connected to a positive pressure source comprising a CO 2  tank. Carbon dioxide is preferred because of its safety, surgical compatibility, and availability. Additionally, the relatively small inner diameter ID of the distal end  71  of the first connector port  59  (about 3/32 in.) produces a high gas flow at the tip  29  of the head portion  25 . As shown in  FIG. 3 , a proximal end  79  of the first connector port  59  has an inner diameter ID 2  that is greater than the inner diameter ID of the distal end  71  of the first connector port forming a shoulder  81  in the first connector port. This constriction in conduit area, under the Venturi principle, with a CO 2  pressure typically at 50 psi dramatically increases the air flow at the tip  29  of the head portion  25 . The space between the tip  69  of the positive pressure conduit and the tip  29  of the head portion  29  also controls the pressure at the tip of the head portion. The increase in pipe area that occurs in the transition between the tip  69  of the positive pressure conduit and the tip  29  of the head portion  25  will slightly decrease the pressure seen at the head portion tip. An additional mechanism to guarantee high air pressure at the tip  29  of the wand  11  is to clamp the outflow tube  19  with a hose clamp (not shown). This will create a closed pressure system. 
         [0029]    Also, because the longitudinal axis of the positive pressure conduit is coincident with the longitudinal axis of the suction conduit, the CO 2  blast produced by the positive pressure source will get a “running start” since there are no turns or bends in the CO 2  path which could slow down the gas flow. The linear CO 2  path also reduces the risk of any “dead spots” that can result from a build up of turbulence at the bends. Finally, the alignment of the positive pressure conduit and suction conduit ensures that the blast of CO 2  impacts the filter screen  27  in a directly perpendicular manner. 
         [0030]    The high pressure, focused blast of CO 2  that results from this construction is needed so that a sufficient amount of gas impinges upon any captured debris in the filter screen  27  to expel the debris. The open areas  77  in the filter screen  27  ensure that a sufficient amount of air can impinge upon the captured debris to expel the debris from the screen. It was found that the range of about 12 to about 30 open areas  77  per square in. is the preferred range to retain bone chips large enough to clog the wand  11  while still providing enough open area to produce a high blast of CO 2  through the screen  27  to expel the debris, and enough open area to provide the desired suction in normal operation. 
         [0031]    A second embodiment of a suction wand  111  of the present invention is shown in  FIG. 5 . The wand  111  of the second embodiment comprises a handle  113  and a valve  115  partially received in the handle moveable between an open and closed position. In the illustrated embodiment, the valve  115  is a ball valve. In the open position, an inflow tube  117  can deliver positive pressure from a positive pressure source (not shown) to a positive pressure conduit  121  in the handle  113 . The positive pressure conduit  121  extends through the handle  113  out a distal end of the handle to a tip portion  125 . A filter screen  127  is disposed in an open, distal end of the tip portion  125 . The wand  111  is configured to deliver a positive pressure force at the tip portion  125  of about 50 psi. 
         [0032]    An outflow tube  119  extends through the handle  113  and connects to a suction conduit  123  in the handle. The suction conduit  123  also extends through the handle  123  and out the distal end of the handle to the tip portion  125 . The positive pressure conduit  121  and suction conduit  123  converge in the handle  113  at a permanent Y-junction  131 . In the closed position, the outflow tube  119  can create a negative pressure gradient at the tip portion  125  by activation of a suction source (not shown) in fluid communication with the outflow tube. 
         [0033]    A third embodiment of a suction wand  211  of the present invention is shown in  FIG. 6 . The third embodiment is substantially the same as the second embodiment except for valve  215  which is configured to control the delivery of pressure in both the suction conduit  223  and the positive pressure conduit  221 . The valve  215  is configured such that in a first position the valve closes the positive pressure conduit  221  and opens the suction conduit  223 . In a second position, the valve  215  closes the suction conduit  223  and opens the positive pressure conduit  221 . In the illustrated embodiment, the valve  215  is a double-ball valve. However, other suitable valves can be used within the scope of the invention. 
         [0034]    A fourth embodiment of a suction wand  311  of the present invention is shown in  FIG. 7 . The wand  311  of the fourth embodiment comprises an inflow tube  317  and an outflow tube  319  adapted for connection to respective positive pressure and negative pressure sources. The tubes  317 ,  319  are connected to a switch  315  at their distal ends. A hose  323  extends from the switch and connects to a positive pressure/suction conduit  321  received in a handle  313  of the wand  311 . A button  232  on the handle  313  is depressable to move the switch  315  between the inflow and outflow tubes  317 ,  319  to selectively communicate one of the tubes with the hose  232 . A tip portion  325  extends from a distal end of the handle  313  and has a filter screen  327  disposed in an open distal end. This embodiment is similarly configured to generate a positive pressure force of about 50 psi at the open distal end of the tip portion  325 . 
         [0035]    Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. 
         [0036]    When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
         [0037]    In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
         [0038]    As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.