Abstract:
A cleaning system includes a surgical tool assembly having a longitudinal shaft and a sleeve surrounding the longitudinal shaft. The system includes an injector head and body that receive the assembly. The head has an inlet coupling that fluidly couples to a pressurized fluid source. The body couples to the head to house the assembly between the head and the body. The body has an outlet coupling to fluidly couple to a vacuum source. When the assembly is housed between the head and the body, at least one fluid pathway is formed between the inlet coupling, the head, the shaft and the sleeve, the body, and the outlet coupling. A positive pressure fluid source is coupled to the inlet coupling and a vacuum source is connected to the outlet coupling to establish a pressure differential across the fluid pathway sufficient to draw the fluid therethrough.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The following relates to sanitizing surgical instruments, and more particularly to sanitizing surgical cutting tools. More specifically, the invention relates to a sanitizer for burs, such as those used during a stapedotomy and other surgical procedures. However, the sanitizing device disclosed herein can be easily adapted to use with other types of instruments such as orthopedic reamers and endoscopic shavers. 
         [0003]    2. State of the Art 
         [0004]    A high-speed cutting tool, such as a bur is used to drill into bone, such as the stapes or cochlea. After using the cutting tool, the tool can be cleaned for reuse or can be disposed. For reusable tools, due to tight tolerances within some cutting tool assemblies, debris and fluid from a surgical procedure may be located in hard to clean areas of the cutting tool assemblies rendering the tools difficult to clean for reuse. Such areas of the cutting tool, even if they can be reached for cleaning, may not be readily cleaned using systems available in a surgical theater within a reasonable amount of time. 
       SUMMARY 
       [0005]    A surgical tool sanitizing system is provided for a surgical tool assembly having a longitudinal shaft and at least one bearing sleeve surrounding the longitudinal shaft. The system includes a sanitizing instrument constructed to house the surgical tool assembly. The sanitizing instrument has an injector head constructed to partially receive the surgical tool assembly. The injector head has an inlet coupling constructed to fluidly couple to a source of pressurized fluid. The sanitizing instrument also includes a sanitizing body constructed to at least partially receive and protect the tool assembly and constructed to connect to the injector head so that the tool assembly is housed between the injector head and the sanitizing body. The sanitizing body has an outlet coupling constructed to fluidly couple to a vacuum source. When the tool assembly is housed in the sanitizing instrument, at least one fluid pathway is formed between the inlet coupling, the injector head, the shaft and bearing sleeve of the tool assembly, the sanitizing body, and the outlet coupling. The system includes a fluid delivery device fluidly coupled to the inlet coupling. The fluid delivery device is constructed to deliver fluid at positive pressure to the injector head through the at least one fluid pathway to the outlet coupling. The system further includes a vacuum source fluidly coupled to the outlet coupling. The vacuum source is constructed to apply a negative pressure to the at least one fluid pathway. The positive pressure and the negative pressure establish a pressure differential sufficient to draw the fluid through the at least one fluid pathway of the tool assembly. 
         [0006]    The injector head may be threadably or otherwise coupled to the sanitizing body such that at least a portion of the tool assembly is compressed between the injector head and the sanitizing body when they are coupled together. The injector head may be constructed to be threaded with respect to the sanitizing body into a seated configuration in which the injector head and the sanitizing body are sealed with each other around the tool assembly. In the seated configuration the tool assembly is completely contained in the sanitizing instrument and is seated between the injector head and the sanitizing body. In the seated configuration, the sanitizing instrument is sealed with the surgical tool assembly so that the fluid pathway extends at least across the entire length of the shaft of the tool assembly and the entire length between the shaft and the bearing sleeve. The injector head and the sanitizing body extend longitudinally and parallel to the tool assembly. 
         [0007]    In use, the injector head can be uncoupled from the sanitizer body to load the tool assembly into the injector head for cleaning or to unload the tool assembly from the injector head after a cleaning operation is complete. Once the tool assembly is loaded and the injector head and sanitizing body are coupled together, the coupling of the injector head longitudinally translates the tool assembly into the bore of the sanitizing body until the tool assembly is seated and sealed between the injector head and the sanitizer body. With the tool assembly fully seated and sealed in the sanitizing instrument, pressurized fluid can be introduced to the injector head while negative pressure is applied at the sanitizing body so that a pressure differential is established to draw the fluid through at least one pathway between the injector head, through the tool assembly, and the sanitizing body. Where the tool assembly includes a longitudinal shaft, at least one bearing sleeve surrounding the longitudinal shaft, and a cutting tool, the at least one pathway includes at least a pathway over the entire length of the shaft and the entire length between the bearing sleeve and the shaft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an isometric assembly view and part schematic view of an instrument sanitizing system, fluid delivery device, and vacuum source, in accordance with an aspect described herein. 
           [0009]      FIG. 2  is an isometric view of an injector head shown in  FIG. 1 . 
           [0010]      FIG. 3  is an isometric view of the injector head shown in  FIG. 2  assembled with a tool assembly shown in  FIG. 1 . 
           [0011]      FIG. 4  is an isometric view of the system shown in  FIG. 1 , partially assembled. 
           [0012]      FIG. 5  is an isometric view of the system shown in  FIG. 1 , fully assembled. 
           [0013]      FIG. 6  is a view of the assembled system shown in  FIG. 5  fluidly coupled to a syringe. 
           [0014]      FIG. 7  is sectional view of the system shown in  FIG. 5 , viewed along section  7 - 7  in  FIG. 5 . 
           [0015]      FIG. 8  is a partial exploded section view of the part noted in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring to  FIG. 1 , a sanitizing system  1  according to an embodiment of the invention is shown along with a fluid delivery device  2  and vacuum source  4 . The system  1  includes a surgical instrument sanitizer  10  for a replaceable tool assembly  20 . The instrument sanitizer  10  includes an injector head  12  and a sanitizing body  14 . The replaceable tool assembly  20  is constructed to be secured and sanitized inside the instrument sanitizer  10 , as described in greater detail below. 
         [0017]    Referring momentarily to  FIGS. 7 and 8 , the replaceable tool assembly  20  includes a tool holder body  36 , a tool shaft  26 , a cutting tool in the form of a bur bit  24  ( FIG. 7 ), and bearing sleeves  90   a  and  90   b,  all described in more detail below. For purposes of an exemplary surgical procedure where the cutting tool might be used, i.e., performing a cochleostomy, the cutting bur  24  preferably has a diameter of less than 1 mm. 
         [0018]    As shown most clearly in  FIG. 8 , the tool holder body  36  of the tool assembly  20  has a proximal portion  36   a,  a distal portion  36   b,  and a tapered neck portion  36   c  between the proximal portion  36   a  and distal portion  36   b.  A longitudinal bore  70  extends longitudinally through the entire tool holder body  36 . The tapered neck portion  36   c  provides a surface  37  that is suitable to seal against an o-ring seal  40  that is disposed in an annular groove  42  formed in the sanitizing body  14 . The longitudinal bore  70  has an enlarged proximal portion  72 , a relatively narrower central portion  74 , and an enlarged distal portion  76 , which may be threaded. Also, a side bore  77  is formed in the distal portion  36   b  of the tool holder body  36 . The side bore  77  extends from an outer surface  81  of the proximal portion  36   a  of the tool holder body  36  into fluid communication with the longitudinal bore  70 . The side bore  77  may extend transversely to the longitudinal bore  70  or may extend at another angle with the longitudinal bore. The side bore  77  is located at a distal end of the proximal portion of the holder body. 
         [0019]    Bearing sleeves  90   a  and  90   b  extend longitudinally within the bore  70  and are longitudinally and preferably rotationally fixed relative to the bore  70 , e.g., sleeve  90   a  is fixed by interference engagement at a notch  96  at a distal end of the bearing sleeve  90   a.  The rotatable tool shaft  26  extends from a proximal end  26   a  to a distal end  26   b  through the bearing sleeves  90   a  and  90   b.  Bearing sleeves  90   a  and  90   b  are longitudinally spaced from each other across a narrow central portion  74 , such that an annular space  79  is formed between the shaft  26  and the bore narrow central portion  74  of the bore  70 . The space  79  permits, among other things, fluid from the side bore  77  to flow into the space  79 , as shown in  FIG. 8 , and move between shaft  26  and bearing sleeve  90   a,  as discussed in greater detail below. 
         [0020]    Referring to  FIG. 7 , the distal end  26   b  of the tool shaft  26  carries a bur holder  98  that receives the bur bit  24 . The bur holder  98  may be permanently integrated with the bur bit  24  or may be adapted to permit an exchange of one bit for another, i.e., selective release and secure capture of a bit. The tool shaft  26  is securely supported by, but rotatable within, the bearing sleeves  90   a  and  90   b  about a tool shaft axis  26   c  ( FIG. 8 ) coaxial with a bore axis  70   c  of the bore  70 , and is preferably made from spring steel wire or tubing with an outer diameter in the range of 0.020 to 0.028 inches. 
         [0021]    The diameter of the bearing sleeves  90   a  and  90   b  are preferably small enough to contact the tool shaft  26  to prevent wobbling or lateral movement of the tool shaft  26 , but not so small as to restrict rotation or longitudinal translation of the tool shaft  26  relative to the bearing sleeves  90   a  and  90   b.  In one embodiment, the inner diameter of the bearing sleeves  90   a  and  90   b  are nominally 0.030 inch, such that the clearance between the tool shaft  26  and the bearing sleeves  90   a  and  90   b  is between 0.002 to 0.01 inch. The clearance between the tool shaft  26  and the bearing sleeves  90   a  and  90   b,  although relatively small, allows space for debris to accumulate during a cutting operation using the bur bit  24 . Such debris must be removed and the surfaces of the tool assembly must be cleaned and sanitized in order for the tool assembly  20  to be reused. 
         [0022]    The proximal end  26   a  of the tool shaft  26  is coupled to drive means  22  for driving the shaft  26 . In a preferred embodiment, the drive means  22  include one or more drive magnets for a magnetic drive system of a drill handpiece (not shown), or appropriate means for engagement with a pneumatic drive system, hydraulic drive system or a direct or reduction-gear electric drive system to provide for controlled high speed rotation of the tool shaft  26  and consequently a bur bit  24 . For example, a magnetic drive system with drive magnets  22  is described in more detail in U.S. Pat. No. 8,403,916. 
         [0023]    After the tool assembly  20  is used in a surgical procedure it may be reusable for another procedure after any fluid and particulate debris accumulated in the tool assembly is removed and the tool assembly is cleaned and sanitized. However, as noted above, in at least one embodiment, the internal clearances of the tool assembly  20  are relatively small, especially between the shaft  26  and the bearing sleeve  90 , which can cause a restriction to fluid flow therebetween. The use of the sanitizing instrument  10  with the tool assembly  20  facilitates a flow of fluid, such as cleaning fluid and/or water, through the internal clearance spaces of the tool assembly  20  to remove debris and clean and sanitize the tool assembly  20 , as described in greater detail hereinbelow. 
         [0024]    The injector head  12  of the sanitizing instrument  10  is shown in greater detail in  FIG. 2 . The injector head  12  has a proximal portion  12   a  and a distal portion  12   b  and a longitudinal bore  12   c  extending through the injector head  12 . A connector  16  ( FIG. 4 ), such as a luer lock, is provided at a proximal end  12   d  of the injector head  12 , for connecting to a fluid delivery device  2  ( FIG. 1 ), such as a syringe  18  ( FIG. 6 ). The connector  16  is in fluid communication with the bore  12   c.    
         [0025]    The distal portion  12   b  of the injector head  12  is stepped with respect to the proximal portion  12   a,  which has a relatively smaller outer diameter. Male threads  12   e  extend around a portion of the distal portion  12   b.  The external male threads  12   e  are constructed to engage with internal female threads  14   a  ( FIGS. 4 and 8 ) of the sanitizer body  14 . Other connections between the distal portion  12   b  and sanitizer body  14  are possible, including, for example, a bayonet locking structure. Also, an o-ring seal  13  ( FIGS. 2 and 8 ) is disposed in an annular groove  12   f  ( FIGS. 2 and 8 ) formed on the distal portion  12   b  at a location between the threads  12   e  and a distal end  12   g  of the injector head  12 . The outer surface of the proximal portion  12   a  is constructed to be grasped for rotation so that the injector head  12  can be threaded into or out of engagement with the sanitizer body  14 . The o-ring  13  is constructed to seal with the sanitizer body  14  when the threads  12   e  of the injector head  12  and the threads  14   a  of the sanitizer body  14  are fully engaged, as shown in  FIGS. 7 and 8 . 
         [0026]    The bore  12   c  is constructed to at least partially receive the tool holder body  36 . For example,  FIG. 3  shows at least a portion of the proximal portion  36   a  of the tool holder body  36  received in the bore  12   c  of the injector head  12 . As shown most clearly in  FIG. 8 , the bore  12   c  has a receiving portion  12   h  that extends proximally from the distal end  12   g  of the injector head  12  to an annular ridge  12   i.  The ridge  12   i  acts as a longitudinal stop and a seat that contacts the proximal end of the tool holder body  36 . The diameter of the receiving portion  12   h  is slightly larger than the outer diameter of the proximal portion  36   a  of the tool holder body  36  to provide an annular space therebetween that permits fluid flow in the annular space when the tool holder body  36  is seated in the receiving portion  12   h  and the tool assembly  20  is positioned in the instrument  10  for cleaning, as shown in  FIGS. 7 and 8 . The bore  12   c  of the injector head is coaxial with the longitudinal bore  70  of the tool holder body  36  so that they form a longitudinal pathway through the injector head  12  and tool holder body  36 , as described in greater detail below. 
         [0027]    The injector head  12  and the tool assembly  20  together can be inserted into sanitizing body  14 , as shown in  FIG. 4 . As shown in  FIG. 7 , the sanitizing body  14  has a longitudinal bore  140  that is constructed to receive the tool assembly  20  and the injector head  12 . The bore  140  has a distal portion  140   a  that extends proximally from an open distal end  142  of the sanitizing body  14  to a proximal end  144  of the distal portion  140   a.  The distal portion  140   a  has a diameter that is slightly larger than the diameter of the distal portion  36   b  of the tool holder body  36 . 
         [0028]    The bore  140  also has a proximal portion  140   b  that extends distally from a proximal end  146  of the sanitizing body  14  to a distal end  148 . The proximal portion  140   b  has internal threads  14   a  constructed to thread with external threads  12   e  of the injector head  12 . 
         [0029]    Also, the bore  140  also has a central portion  140   c  that extends between the distal portion  140   a  and the proximal portion  140   b.  As best shown in  FIG. 8 , the central portion  140   c  is defined by an annular wall  150  extending distally from the distal end  148  of the proximal portion  140   b  to an annular seat  152 . The central portion  140   c  also is defined by a tapered section  154  that tapers distally from an inner diameter of the annular seat  152  to the annular groove  42  that extends to the proximal end of the distal portion  140   a  of the bore  140 . The diameter of the annular wall  150  is shown as being larger than the diameter of the annular groove  42 . The afore-mentioned o-ring seal  40  is disposed in the groove  42  and is configured to seal with the tapered neck  36   c  of the tool holder body  36 , as shown in  FIG. 8 . 
         [0030]    As shown in  FIGS. 1 and 4  to  7 , the sanitizing body  14  has a tapered barb  14   b  at distal end  142 . The barb  14   b  is constructed to fit into a tube (not shown) of a vacuum source  4  ( FIG. 1 ). Of course, it will be appreciated by those of ordinary skill in the art, that the sanitizing body  14  can be constructed with alternative connections instead of barb  14   b.  For example, the sanitizing body  14  can be constructed with a luer lock fitting at the distal end  142  to connect to a mating connector of the vacuum source. 
         [0031]    In use, the injector head  12  can be unscrewed from the sanitizer body  14  to load the tool assembly  20  into the injector head  12  for cleaning or to unload the tool assembly  20  from the injector head  12  after a cleaning operation is complete. To load the tool assembly  20  into the injector head  12 , the proximal portion  36   a  of the tool holder  36  is inserted into the bore  12   c  of the injector head  12 , as shown in  FIG. 3 . With the proximal portion  36   a  of the tool holder body  36  inserted into the injector head  12 , the remainder of the tool assembly  20  can be guided into the sanitizer body  14 , as shown in  FIG. 4 . Once the external threads  12   e  engage the internal threads  14   a,  the injector head  12  is threaded to the sanitizing body  14  to longitudinally translate the tool assembly  20  into the bore  140  of the sanitizing body  14  until at least seal  13  seals with annular wall  150  and seal  40  seals with tapered neck  36   c,  in which case the tool assembly is considered fully seated in the sanitizing instrument  10 , as shown in  FIGS. 7 and 8 , for example. 
         [0032]    With the tool assembly  20  fully seated in the sanitizing instrument  10 , fluid pathways denoted by arrows  201 ,  202 ,  203 , and  204  in  FIG. 8  are defined between injector head  12 , tool assembly  20 , and sanitizing body  14  so that a pressurized fluid introduced in the injector head  12  can flow through the tool assembly  20  and out the sanitizing body  14  during a cleaning operation, described in greater detail below. 
         [0033]    The connector  16  can be fluidly coupled to the syringe  18  as shown in  FIG. 6  and the barb  14  can be fluidly coupled to the vacuum source  4 . The syringe  18  is preloaded with a fluid (e.g., cleaning fluid and/or water). To clean the tool assembly  20 , fluid from the syringe  18  is introduced at a positive pressure into the injector head  12  by pushing on plunger  20  while a negative pressure is applied simultaneously to the sanitizer body  14  by the vacuum source  4 . Negative and positive pressure refer, respectively, to relative pressures below and above atmospheric pressure. The positive and negative pressures provided by the syringe and the vacuum source establish a pressure differential sufficient to draw the fluid through the fluid pathways. The fluid drawn through the fluid pathways displaces debris and cleans and sanitizes the surfaces that define the pathways. 
         [0034]    In at least one example, the syringe and the vacuum source establish a 31 psi differential pressure, which is sufficient to draw the fluid through the fluid pathways. In such an example, about 6 psi of differential vacuum is needed to be provided by the vacuum source  4 , while about 25 psi of positive pressure is needed to be provided by the syringe. The foregoing examples are calculated as follows. A typical 6 ml syringe has a ½″ diameter plunger, having a cross sectional area of 0.2 square inch. According to NASA a human male can apply 7 lbf with their thumb for extended periods of time. Assuming only 70% of the 7 lbf is applied, the pressure generated on the fluid in the 6 ml syringe would be about 25 psi (5 lbf/0.2 square inch=25 psi). In testing it has been shown that the combined use of positive and negative pressures to establish a pressure differential can speed up the cleaning of the tool assembly  20  when compared to applying only positive or negative pressures alone. Moreover, increasing the pressure differential, say be applying a relatively larger positive pressure with the syringe  18  can further reduce the cleaning time. For example, hospital gasses are generally pressurized at about 50 to 59 psig. Thus, if one were to use a syringe pressurized using such hospital gasses, the total differential could be about 65 psig (59 psig−(−6) psig=65 psig). 
         [0035]    Upon introduction of fluid with a sufficient pressure differential established by the combination of the syringe  18  and vacuum source  4 , the fluid moves through the bore  12   c  of injector head into and around the proximal portion  36   a  of the tool holder body  36 , as shown by the arrows shown in  FIG. 8 . Some of the fluid from the syringe  18  enters the tool holder body  36  through a space between the bore  70  and tool shaft  26  as indicated by arrow  201 . Some of the fluid from the syringe  18  enters the tool holder body  36  between an annular space between the magnet  22  and the tool holder body  36 , as indicated by arrow  202 . Also, some of the fluid from the syringe  18  moves around the proximal portion  36   a  of the tool holder body  36  between the receiving portion  12   h  of the bore  12   c  of the injector head  12  and the tool holder body  36 , as indicated by arrow  203 . The flows indicated by arrows  202  and  203  move in the annular space between the proximal portion  36   a  and the receiving portion  12   h  to a space  180  defined between the proximal end  12   g  of the injector head  12  and annular wall  150 , annular seat  152 , and tapered portion  154  of the sanitizing body  14 . The fluid received in space  180  is redirected by its defining surfaces into the side bore  77  as indicated by arrow  204  and flows into space  79 . The fluid flow denoted by arrow  201  can pass between the relatively small clearance between the bearing sleeve  90   b  and shaft  26  so that it also passes into space  79 . The fluid flowing into space  79  then flows distally between shaft  26  and bearing sleeve  90   a  all the way to the bur bit  24 . The fluid washes over the bur bit  24  to clean the bit, upon which the fluid is discharged out of the distal end  142  of the sanitizing body  14 . Thus, all of the fluid introduced by the syringe  18  cleans the entire surface of the shaft  26 , the bit  24 , and the inner surfaces of the bearing sleeves  90   a  and  90   b.  When sufficient amount of fluid passes through the instrument (or a sufficient time of fluid flow has elapsed), fluid flow is stopped and the sanitizing instrument  10  can be opened by unscrewing the injector head  12  from the sanitizing body  14  to remove the cleaned tool assembly  20  therefrom. 
         [0036]    There have been described and illustrated herein embodiments of a sanitizing system, sanitizing instrument, and a method of cleaning a tool assembly. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while a particular injector head, tool assembly, and sanitizing body configuration has been disclosed, it will be appreciated that another conforming arrangement can be used as well, provided that such arrangement allows for fluid to clean the entire facing surfaces of the shaft and bearing sleeves of the tool assembly while the tool assembly is housed between the injector head and the sanitizing body. Also, while a bur has been shown as an exemplary cutting tool, other cutting tools can similarly be provided to the distal end of the shaft, including, for example, hollow cutting tools and arthroscopic shaver blades and orthopedic intramedullary reamers. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.