Abstract:
A suction probe system for cleaning debris from a surgical site includes a probe tip, a filter unit in fluid communication with the probe tip, and a suction source in fluid communication with the filter unit. The filter unit includes a cylindrical filter having an inner chamber attached to the suction source and an outer surface which accumulates debris particles too large to pass through holes within the cylindrical filter. The filter unit also includes a slider having an open-ended cylinder which is slid along the outside of the cylindrical filter to remove accumulated debris particles and to push these debris particles into a reservoir within the filter unit. The slider and the probe tip can be made integral parts of a single sliding member.

Description:
BACKGROUND INFORMATION 
     1. Field of Invention 
     This invention relates to a probe forming a part of a surgical suction system for the removal of debris from a surgical site, and, more particularly, to such a probe including an internal filter for removing and holding larger pieces of such debris from waste slurry flowing through the probe. 
     2. Description of the Related Art 
     The patent literature describes a number of suction probes for use in surgical suction systems to remove debris from a surgical site, with the probe including or being associated with an internal filter for removing and holding the larger pieces of waste slurry flowing through the probe. Such a suction probe has an inlet large enough to permit the entrance of debris particles too large to be handled reliably through the remaining portion of the suction system, such as the conduit leading to a suction source. These particles are trapped within the internal filter. Each such suction probe is separable into two pieces so that the internal filter can be cleaned or replaced as it becomes clogged or as tissue samples are needed, for example, for pathology. 
     For example, U.S. Pat. No. 4,468,217 to Kuzmick et al. describes a surgical suction tip including an inner removable filter device. The housing includes a suction opening at one end and a filter receiving handle formed as a sleeve at the other end; the inner removable filter device is connected in the filter receiving handle by a quick connect-disconnect means; the housing tapers to increase in size from its suction opening to the filter device. A seal is located between the housing and the filter device. Within this device, filtration occurs through a cylindrical filter having a number of holes between a chamber within the cylindrical filter and a chamber within the device but outside the cylindrical filter. The chamber within the cylindrical chamber is in fluid communication with a suction source, while the chamber outside the cylindrical chamber is in fluid communication with an aperture at the distal end of the probe tip, through which debris is sucked. 
     U.S. Pat. No. 5,779,649 to Herbert describes a surgical suction wand comprising a generally tubular body with a hollow tip at one end thereof, a cap releasably closing the other end of the tubular body, and a filter member within the body and joinable to the under surface of the cap. The filter member is wedge-shaped, having a number of holes through which debris is sucked into a space within the filter. The filter member is removed, along with the cap, and is cleaned and returned to the interior of the tubular body as required. The cap snaps in place on the tubular body, with a ridge extending around an end of the tubular body snapping in place within a groove extending around an end of the cap, and with a tab being provided to ease the disengagement of the snap fit. 
     U.S. Pat. No. 5,630,939 to Bulard et al. describes a filter assembly for elective use in conjunction with a surgical evacuation system. The filter assembly includes a filter housing having a head portion and a body portion with a through passageway extending therebetween defining a filter receiving chamber. The head portion is connectable to an aspirator tip and the body portion is connectable to a flexible suction conduit. A filter element is disposed within the filter receiving chamber of the filter housing. The filter element includes a head member having a fluid flow passageway extending therethrough, a fluid impermeable base member spatially disposed from the head member, and a fluid permeable body member disposed between the head member. The head member and the body member are joined by a cylindrical surface having an O-ring seal, so that the head member and the body member are separated by twisting and sliding to install, remove, or replace the filter element. 
     U.S. Pat. No. 5,766,134 to Lisak et al. describes a collector unit for collecting tissue or bone from a dental patient during a dental implant procedure. The collector unit includes a cover member, a filter support member, a filter medium, and a gasket support member. The support member is mountable within the cover member with the gasket member positioned therebetween to form the unit. The support member has a pair of spaced-apart, opposed filter support arms for removably supporting a substantially flat section of filter medium, so that the filter medium overlays an input passageway through which liquid is drawn. After the unit is disassembled, the filter medium is removable from the supporting structure so that it can be positioned in a flat orientation to facilitate the removal of bone or tissue specimens therefrom. Once removed, the filter medium cannot be reattached to the supporting structure. 
     U.S. Pat. No. 5,807,353 to Schmitz describes an aspiration device for separating liquid content of a body fluid and irrigation fluid, if any, from solid material. The device includes an integrally formed housing and an integrally formed separating element, which is detachably inter-connectable to the housing. The housing includes a proximal segment for defining a hollow space to receive part of the separating element. The separating element includes a filter element for separating the liquid content of the body fluid from the solid matter and for collecting the solid matter in the interior of the filter element. The separating element further includes an end connector for interlocking the separating element with the housing, and an egress tube for conveying the liquid content outside the aspiration device. The filter element is a slotted cylinder, with debris being sucked through and end of the cylinder, and with liquid being further sucked outward through the slots while solid material remains within the cylinder. The device is cleaned, or collected material is removed, by twisting a threaded end connector so that it is disengaged from the proximal end of the housing. The separating element is then removed, so that the filter can be cleaned or replaced. 
     Each of the patents described above discloses a suction device having an internal filter which can be cleaned or removed and replaced only when the suction device is taken apart to reveal the internal filter. What is needed is a method providing for cleaning the filter without disassembling the device and without a need to wipe the filter. The process of disassembly, wiping, and reassembly is relatively time consuming, and must often be performed several times during a surgical procedure. This process results in a number of pieces of the suction device and the filter, which must be separately handled and reassembled. A lack of the suction process during this process can also interrupt other surgical procedures taking place. Furthermore, what is needed is an ability to hold trapped debris so that it is unnecessary to handle such debris during a surgical procedure. 
     A number of U.S. patents describe surgical suction probes without internal filters. For such a device to be used reliably to remove debris from a surgical site, solid fragments the tip aperture must be small enough to prevent the aspiration of particles from the waste slurry which are large enough to clog the conduit extending between the suction probe and a vacuum source generating the suction, the vacuum source itself, or a fluid separation device associated with the vacuum source. On the other hand, fragments too large to pass through the aperture may be held externally at the aperture or allowed to fall back into the surgical site. What is needed is a mechanism allowing such fragments to be trapped and held within the suction probe, without being allowed to flow along the conduit to the vacuum source, and without being redeposited at the surgical site. This need is apparent when the suction probe is used to clean debris from the site of an orthopaedic procedure, in which bone fragments of various sizes are produced. 
     Examples of such patents include U.S. Pat. No. 5,520,668 to Greff et al., which describes a surgical suction system and method including a source of suction and a conduit having a distal end and a proximal end. At its distal end, the conduit has a diameter not greater than about ⅝ inch to provide limited access to the surgical site and an inside diameter not less that about ¼ inch to accommodate the bone fragments in the waste slurry. A coupling is provided for connecting the proximal end of the conduit to the suction source in order to provide suction at the distal end of the conduit at a velocity not less than about ninety miles an hour. A fluid containment vessel can be connected between the conduit and the source of suction to provide a liquid trap for the waste slurry passing along the conduit. 
     U.S. Pat. No. 4,878,900 to Sundt describes a probe and suction device for use during surgery, including an elongated tubular handle adapted for connection to a source of suction and a separable elongated tubular probe and suction member. It includes a suction regulating orifice in the handle and is characterized by a positive snap-on rotatable connection between the handle and the probe and suction member. The distal end of the probe and suction member is blunted to avoid tissue damage. 
     U.S. Pat. No. 5,123,840 to Nates describes a suction probe including a controllable suction port, which the individual using the probe can partly or totally cover with a finger to control the level of suction available at the probe tip, through which debris is removed. 
     U.S. Pat. No. 4,068,664 to Sharp et al. describes a surgical suction wand assembly including a modular suction wand having a hollow suction tip, along which a number of laterally disposed external apertures extend. The tip may be provided with an elongated interiorly disposed tube simultaneously providing for effective aspiration of small amounts of liquid as well as a large suction area for efficiently aspirating larger volumes with minimal opportunity for obstruction. While the apertures in the suction tip provide a filter preventing the aspiration of larger fragments, such fragments may be expected either to remain held in place externally on the suction tip as it is used, or to fall back into the surgical site. Thus, what is needed is a mechanism for removing such fragments from these apertures and for safely holding them as the surgical wand is used. 
     SUMMARY OF THE INVENTION 
     It is therefore a first objective of the present invention to provide a surgical suction probe having an internal filter which can be cleaned without disassembling the suction probe. 
     It is a second objective of the present invention to provide a surgical suction probe having an internal reservoir for holding debris cleaned from an internal filter. 
     According to a first aspect of the present invention, there is provided apparatus for removing debris from a surgical site. The apparatus includes a hollow probe tip, a filter chamber, and a slider. The hollow probe tip includes a tip aperture and an internal passageway extending from the tip aperture. The filter chamber includes a reservoir, an output port connectable to a suction source, and a filter surface, with the first side of the filter surface being in fluid communication with a passage, within the hollow probe tip, and with a second side of the filter surface in fluid communication with the internal passageway of the hollow probe tip. The slider is movable within the filter chamber, with movement of the slider within the filter chamber in a first direction pushing debris within the filter chamber from the first side of the filter surface into the reservoir. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a surgical suction system built in accordance with the present invention; 
     FIG. 2 is longitudinal cross-sectional view of a first embodiment of a surgical suction probe built in accordance with the present invention for use as a part of the system of FIG. 1; 
     FIG. 3 is a fragmentary cross-sectional view of a filter section in of the probe of FIG. 2, showing internal features used fort he attachment of a distal section of the probe to the filter section; 
     FIG. 4 is a transverse cross-sectional view of the surgical suction probe of FIG. 1, taken as indicated by section lines IV—IV in FIG. 2; 
     FIG. 5 is a fragmentary longitudinal cross-sectional view of a distal end of a filter housing in engagement with a proximal end of a slider, made in accordance with a third embodiment  80  of the present invention; 
     FIG. 6 is a fragmentary longitudinal cross-sectional view of a proximal end of a filter housing made in accordance with a fourth embodiment of the present invention. 
    
    
     DESCRIPTION OF THE INVENTION 
     FIG. 1 is a schematic view of a surgical suction system built in accordance with the present invention for removing debris from a surgical site, including a probe tip  10 , a first filter  12 , a second filter  14 , and a vacuum source  16 . The surgical suction system may be partly composed of a central vacuum system within the hospital, with the probe tip  10  and the first filter  12  being disposed within an operating room, and with the second filter  14  and the vacuum source  16  being disposed in another part of the hospital in the form of a central vacuum system. In accordance with the present invention, the first filter  12  includes a filter section  17 , a slider  18 , and a reservoir  19 . When the slider  18  is moved into the filter section  16 , debris held on a surface of a filter surface (not shown) within the filter section  17  is scraped off the filter surface and deposited within the reservoir  19 . 
     FIG. 2 is a longitudinal cross-sectional view of a surgical suction probe  24  built in accordance with a first embodiment of the present invention. In this embodiment, the slider  18  and the probe tip  10  are configured as integral parts of a sliding member  26 . The filter section  17  includes a housing  20  with the reservoir  19  near a proximal end  28  of the filter section  17 , a cylindrical filter  30 , and a hollow tube  32  extending through the proximal end  28  in communication with a chamber  34  within the cylindrical filter  30 . The cylindrical filter  30  includes a number of holes  36 , extending between the chamber  34  within the filter  30  and a chamber  38  within the housing  19 . Preferably, the filter holes  36  extend in a hole pattern  40  along each of two diametrically opposed sides of the cylindrical filter  30 , with the individual holes  36  being aligned in a common direction, facilitating the manufacture of the cylindrical filter  30  by a thermoplastic molding process. 
     To use the surgical suction probe  24  to remove debris from a surgical site, the external end  42  of the hollow tube  32  is connected to a vacuum system by means of a flexible hose  44 . The probe tip  10  is then placed within the surgical site so that debris is sucked inward through a tip aperture  46  at the distal end of the probe tip  10 . The debris is pulled through the hollow probe tip  10  and through a chamber  48  within the slider  18 . The debris is then pulled into the chamber  38  within the filter section  17 . The portions of the debris which can pass through the filter holes  36  enter the chamber  34  within the cylinder filter  30 , while particles which are too big to pass through the filter holes  36  remain within the chamber  38 , generally being held within the annular region  50  within the chamber  38  outwardly adjacent the cylindrical filter  30 . 
     The tip aperture  46  is preferably substantially larger in diameter than each of the individual filter holes  36 , so that debris particles within a range of sizes, having been drawn into the suction probe  10 , are not allowed to pass through this probe  10  into the hollow tube  32  and thereafter into the flexible hose  44  (shown in FIG. 1) to the associated vacuum system. Also, the individual filter holes  36  are preferably substantially smaller in diameter than the hollow tube  32 . These conditions are met, for example, with a tip aperture  46  having a diameter of 4.8 mm (0.188 inch), individual filter holes  36  having diameters of 1.9 mm (0.073 inch), and a hollow tube  32  having an internal diameter of 6.4 mm (0.250 inch). Furthermore, to prevent debris from being trapped within the probe tip  10 , the tip aperture  46  is preferably the smallest part of the opening  52  extending through the probe tip. For example, this opening  52  may be tapered from the tip aperture  46 , having a diameter of 4.8 mm (0.118 inch) to an opening at the proximal end  54  of the probe tip  10  having a diameter of 6.4 mm (0.250 inch). 
     The suction probe  24  can be used in this way to remove debris until debris accumulates within the annular region  50  outwardly adjacent the cylindrical filter  30  to an extent sufficient to substantially block the flow of material into the cylindrical filter  30 . As this occurs, the efficiency of the suction probe  24  declines to a noticeable extend, and the probe is removed from the surgical site so that debris can be cleared from the annular region  50  by manually moving the slider  18  in the direction of arrow  18  in the direction of arrow  56 , with the slider  18  moving into the annular region  50 . This movement pushes debris held within the annular region  50  into the reservoir  19  forming a proximal portion of the chamber  38  within the filter section  17 . Thus, with the housing  20 , the slider  18 , and the cylindrical filter  30  being aligned coaxially, the annular region  50  is cleared with a single movement of the slider  18 . After debris is cleared in this way, the slider is manually returned to its initial position, opposite the direction of arrow  56 , and the process of removing debris from the surgical site is continued. 
     This method for cleaning debris from the annular region  50  is practical because the suction probe  24  is disposable, being discarded after use on a single patient or on a single surgical site. Thus, the reservoir  19  can be configured to be of adequate size to avoid overfilling before the suction probe  24  is discarded. Typically, the suction probe  24  aspirates a mixture of air, liquid, and particles such as bone fragments and pieces of bone cement. This mixture does not fill the chamber  38  with liquid, so the slide  18  can be moved in the direction of arrow  56  while compressing air within the chamber  38  and while forcing a slurry of small particles and liquid into filter holes  36  which have not become totally clogged. 
     FIGS. 3 and 4 show a mechanism for controlling movement of the slider  18  into the filter chamber  38 . This type of control is needed to allow the suction probe  24  to be operated as described above; without a mechanism to hold the slider  18  in its extended position, as shown in FIG. 2, the slider  18  would be pulled inward, in the direction of arrow  56  by suction established within the filter section chamber  38 . FIG. 3 is a fragmentary longitudinal cross-sectional view of the distal end  58  of the filter housing  20 , particularly showing locking segments  60  extending radially inward, while FIG. 4 is a transverse cross-sectional view of the suction probe  24 , taken as indicated by section lines IV—IV in FIG.  2 . 
     The slider  18  includes four integral locking tabs  62 , extending outward from its proximal end  64  in a cruciform pattern. During the cleaning of debris from a surgical site, these four locking tabs  62  are held within four corresponding circumferential grooves  64 , each of which extends partly around a locking segment  60  at the distal end  58  of the filter housing  20 . A groove  66  extends between each pair of adjacent locking segments  60 , providing four grooves  66  in a cruciform pattern. Thus, when it is determined that the annular region  50  outwardly adjacent the cylindrical filter  30  is to be cleaned, the suction probe  24  is removed from the surgical site, and the slider  18  is rotated in the counterclockwise direction of arrow  68  relative to the filter section  17 . Such rotation ends with the four locking tabs  62  aligned with the four corresponding grooves  68 , in a relationship allowing the slider  18  to be moved in the direction of arrow  56  into the chamber  38  within the filter section  17 . 
     After the annular region  50  is cleaned by moving the slider  18  into the chamber  38 , the slider  18  is pulled outward, opposite the direction of arrow  56 , and is rotated as needed to align the locking tabs  62  with the grooves  68 . When this alignment occurs, the slider  18  is pulled outward into the fully extended position in which it is shown in FIG.  2 . The slider  18  is then rotated opposite the direction of arrow  68  relative to the filter section  17 , locking the slider  18  in place in its fully extended position, and the probe tip  10  is returned to the surgical site to continue the suction process. 
     A sliding seal is maintained between the proximal end  64  of the slider  18  and the internal surface of the filter housing  20  by means of an O-ring seal  70  held within a grooved seal holder  72  of the slider  18 . This outward-extending seal holder  72  also contacts the inward-extending locking segments  60  of the filter housing  20 , preventing the slider  18  from being separated from the filter housing as the slider  18  is pulled opposite the direction of arrow  56 . 
     The filter housing  20  and various other members of the suction probe  24  are preferably composed of a transparent material, such as a transparent form of polycarbonate, so that material clogging the filter can be easily observed. 
     Referring again to FIG. 1, a surgical suction probe built in accordance with a second embodiment of the present invention includes a first filter  12  which is separate from the probe tip  10 , but which includes a slider  18  and a reservoir  19  operating as described above relative to the first embodiment  24 . The first filter  12  and the probe tip  10  are separated by a flexible hose  74 , through which debris is drawn. Thus, the flexible hose  74  of FIG. 1 is optional, only being used as a part of a second embodiment of the suction probe. 
     FIG. 5 is a fragmentary longitudinal cross-sectional view of a distal end of a filter housing  76  in engagement with a proximal end of a slider  78 , with both the filter housing  76  and the slider  78  being made in accordance with a third embodiment  80  of the present invention. The filter housing  76  includes an internal thread  82 , while the slider  78  includes an external thread  84 , forming an alternative arrangement for locking the slider  78  in place on the filter housing  76  during the use of the suction probe  80  to remove debris from a surgical site. Each of the threads  82 ,  84  may be a single thread, extending partly or fully around the circumference of a threaded surface, or there may be two or more threads on the housing  76  and the slider  78 , spaced apart from one another to extend in an intertwined manner or limited in length to separate portions of the circumference of the threaded surface. An advantage of using multiple threads arises from the fact that multiple angular positions are available for starting the process of screwing the slider  78  into a locked condition on the filter housing  76 . An advantage of this third embodiment  80  over the first embodiment  24 , discussed above in reference to FIGS. 2-4, arises from the ease with which such threads are engaged, compared with a need, in the first embodiment  24 , to align the locking tabs  62  with the grooves  66 , before the slider  18  can be moved opposite the direction of arrow  56  into a locked condition. Other aspects of the filter housing  76  and the slider  78  are the same as those of the corresponding filter housing  76  and the slider  18  of the first embodiment  24 . 
     Referring to FIGS. 1 and 5, during the process of assembling the first embodiment  24  of the suction probe the various elements are joined in a manner allowing the slider  18  to be moved in the direction of arrow  56  and opposite thereto, but so that it cannot be separated from the remaining parts of the suction probe. The distal end  28  is permanently attached within the filter housing  17 , for example, by an adhesive. The grooved seal holder  72  prevents separation of the slider  18  in the direction of arrow  56  from the filter housing  17 . The debris trapped in the reservoir  19  remains there as the suction probe  24  is disposed. Similar conditions occur in the third embodiment  80  of the suction probe, with the slider  78  being trapped to slide within the filter housing  76 , and with debris being trapped in the reservoir. In many applications, this is advantage, providing for the containment of potentially dangerous waste. 
     In some applications, there is a need to remove and save the debris stored in the reservoir  19 , for example, for examination by a pathologist. Therefore, FIG. 6 is a fragmentary longitudinal cross-sectional view of the proximal end of a fourth embodiment  88  of the suction probe, which is configured so that the distal end  90  may be removed from the filter housing  92 , providing for the removal of debris from the reservoir  19 . An O-ring  94  in a groove  96  within the distal end  90  forms a seal between the distal end  90  and the filter housing  92 . The distal end  90  and the filter housing  92  are also provided with mating threads  98 , which hold the distal end  90  attached to the filter housing  92 . The contents of the reservoir  19  are emptied after the distal end  92  is unscrewed from the filter housing  92 . 
     While the present invention has been described in its preferred forms of embodiments with some degree of particularity, it is understood that this description has been given only by way of example and that numerous changes in the details of construction, fabrication, and use, including changes in the combination and arrangement of parts, may be made without departing from the spirit and scope of the invention.