Patent Publication Number: US-2012029294-A1

Title: Cannula

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the priority U.S. Provisional Application 61/166,971, filed Apr. 6, 2009, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to surgical instruments and, more specifically is related to a cannula for use in arthroscopic procedures. 
     2. Description of the Background Art 
     It is well known to use specialized tools to aid insertion of surgical instruments such as arthroscopes, cutting and/or trimming tools, clamps, optical devices, etc. into a body for use during arthroscopic procedures in which movable joints are repaired, replaced or surgically constructed. For example, a cannula in the form of a rigid tube is often inserted into the body and used to direct the surgical instruments to a desired location in an operative field while minimizing trauma to surrounding tissue. 
     Conventional cylindrical cannulas are limited to use with instruments having an outer diameter less than that of the inner diameter of the cannula. Moreover, the leading tip of the cannula may be submerged in pooled body or irrigation fluids in the operative field whereby visualization of the joint, and position of the leading tip relative to the joint, is obscured. In these situations, accurate placement of the leading tip relative to the joint, and ultimately, placement of the inserted instrument, can be difficult. 
     SUMMARY 
     A device is provided for introducing surgical tools into a body. The device includes a handle and a cannula extending from the handle. The cannula has a first end fixed to the handle, and a second end opposed to the first end which corresponds to the leading tip. The cannula has a cross sectional shape that is a minor arc which defines a concave tool-receiving surface, and a convex outer surface opposed to the tool-receiving surface. The tool-receiving and outer surfaces extend axially from the handle to the second end of the cannula. In addition, a cannula fluid channel is disposed between the tool-receiving and outer surfaces. The cannula fluid channel extends from the handle to the second end of the cannula, and opens to the cannula exterior at the second end (leading tip) of the cannula. 
     Advantageously, since the peripheral shape of cannula has the form of a minor arc, the device provides an arcuately shaped, trough-like surface which receives and guides surgical instruments, and is not limited to instruments of any particular diameter. Also advantageously, by providing a fluid channel within the body of the cannula, waste irrigation fluid, blood, or tissue fragments can be removed from the vicinity of the leading tip of the cannula by drawing them into the fluid channel so as to permit clear visualization of the joint and the position of the device relative to the joint. Alternatively, the fluid channel can also be used to introduce irrigation fluids into the surgical field. 
     In some aspects, a device for introducing surgical tools into a body is provided. The device includes a handle, and a cannula extending from the handle. The cannula includes a first end fixed to the handle, and has a shape that is a minor arc in cross section. The arcuately shaped cannula defines a concave tool-receiving surface, and a convex outer surface opposed to the tool-receiving surface. The tool-receiving and outer surfaces extend axially from the handle to a second end of the cannula that is opposed to the first end, and a cannula fluid channel is disposed between the tool-receiving and outer surfaces. The cannula fluid channel extends from the handle to the second end of the cannula, and opens to the cannula exterior at the second end of the cannula. 
     The device may include one or more of the following features: The minor arc has a circumferential arc length in a range between 20 degrees and 180 degrees. The cannula fluid channel is arcuate in cross sectional shape. The cannula further includes opposed sidewalls that join peripheral side edges of the tool-receiving surface and the outer surface, and the sidewalls, the tool-receiving surface and the outer surface define the cannula fluid channel. The cannula further includes a pair of ribs extending radially between the tool-receiving surface and the outer surface, and the ribs, the tool-receiving surface and the outer surface define the cannula fluid channel. The ribs are positioned along longitudinally extending peripheral edges of the tool-receiving and outer surfaces. The ribs are circumferentially spaced apart from longitudinally extending peripheral edges of the tool-receiving and outer surface. A longitudinal axis of the cannula is angled in the range of 20 to 70 degrees with respect to a longitudinal axis of the handle. The handle includes a handle fluid channel in fluid communication with the cannula fluid channel, and a connector is provided within the fluid passageway configured to connect the handle fluid channel to an external fluid channel. The connector includes a fluid control valve. The handle includes a first end, a second end opposed to the first end and the connector is disposed on the first end. In this embodiment, the first end of the cannula is connected to a second end of the handle, and the handle fluid channel and cannula fluid channel provide a continuous fluid flow pathway between the second end of the cannula and the first end of the handle. The handle includes a first end, a second end opposed to the first end and the connector is disposed on the second end. In this embodiment, the first end of the cannula is connected to a second end of the handle, and the handle fluid channel and cannula fluid channel provide a continuous fluid flow pathway between the second end of the cannula and the second end of the handle. 
     In some aspects, a device for introducing surgical tools into a body is provided. The device includes a handle, and a cannula fixed to an end the handle. The cannula includes an elongate, hollow, double-walled blade. The blade is shaped such that an inner wall and outer wall are spaced apart. In addition, the inner and outer wall are shaped to form coaxial minor arcs when viewed in a section transverse to a blade longitudinal axis, and the space between the inner and outer wall defines a fluid channel. 
     Modes for carrying out the present invention are explained below by reference to an embodiment of the present invention shown in the attached drawings. The above-mentioned object, other objects, characteristics and advantages of the present invention will become apparent from the detailed description of the embodiment of the invention presented below in conjunction with the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of the introducing device. 
         FIG. 2  is a top view of the device of  FIG. 1 . 
         FIG. 3  is a side sectional view of the device of  FIG. 1 . 
         FIG. 4  is a side view of the second end of the cannula as seen in circle C of  FIG. 3 . 
         FIG. 5  is a top view of the second end of the cannula of  FIG. 4 . 
         FIG. 6  is a side sectional view of the second end of the cannula as seen along line A-A of  FIG. 5 . 
         FIG. 7  is a cross-sectional view of the cannula as seen along line B-B of  FIG. 6 . 
         FIG. 8  is another embodiment of the cross-sectional view of the cannula as seen along line B-B of  FIG. 6 . 
         FIG. 9  is another embodiment of the cross-sectional view of the cannula as seen along line B-B of  FIG. 6 . 
         FIG. 10  is another embodiment of the cross-sectional view of the cannula as seen along line B-B of  FIG. 6 . 
         FIG. 11  is a side sectional view of the handle of the device of  FIG. 1 . 
         FIG. 12  is a top sectional view of the handle of the device of  FIG. 1 . 
         FIG. 13  is a side sectional view of another embodiment of the handle. 
         FIG. 14  is a top sectional view of the handle of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION 
     A device  10  for introducing surgical tools into a body will be described with reference to the figures. In the following description, references to orientations such as upper, upward, lower, downward, etc. are made for descriptive purposes with respect to the orientation of the device shown in  FIG. 1  rather than to imply any absolute relative orientation. 
     Referring now to  FIG. 1 , the device  10  includes a slotted cannula  20  supported on a handle  80 . The cannula  20  is an elongate plate  21  having a first end  22  rigidly connected to an end  84  of the handle  80 . Elongate plate  21  is curved in the width direction so that the cannula  20  has a cross-sectional shape that is a minor arc opening upward. As a result of this configuration, the cannula  20  includes an upward-facing, concave tool receiving surface  26 , and an opposed, downward-facing, convex outer surface  28 . In some embodiments, the minor arc has a circumferential arc length in a range between 20 degrees and 180 degrees. 
     The cannula  20  extends linearly along a longitudinal axis  36 , and has a width (e.g. the dimension transverse to the longitudinal direction) that is much smaller than its axial length. In some embodiments, the cannula  20  has a width in a range of 0.5 cm to 2.0 cm, and a corresponding axial length in a range from 3 cm to 13 cm. The particular dimensions of the cannula  20  are determined based on the intended use of the device  10 . For example, a cannula  20  to be used in hip arthroscopy may have axial length of about 10 cm, whereas a cannula  20  to be used in knee arthroscopy may have an axial length of about 7 cm, and a cannula  20  to be used in shoulder arthroscopy may have an axial length of about 5 cm. The dimensions disclosed here are presented to provide a relative scale of the cannula  20 , and are not intended to be limiting. 
     The cannula  20  has a second end  24  opposed to the first end  22 , the second end  24  corresponding to the end of the device  10  that is inserted into the body. The second end  24  has a rounded shape to ease insertion and to minimize trauma to soft and hard tissues. As seen in  FIG. 2 , the second end  24  is rounded across the width of the cannula  20 . In addition, as seen in  FIG. 4 , the leading end or tip  25  of the second end  24  is also rounded across the depth of the tip  25 . As a further means to ease insertion and minimize injury, the second end  24  is provided with a taper  23  such that the overall depth of the cannula  20  gradually reduces to a minimum depth in the vicinity of the tip  25 . 
     Referring now to  FIGS. 3 and 6 , the plate  21  of the cannula  20  is a hollow member whereby a vacancy  40  exists between the tool receiving surface  26  and the outer surface  28 . The vacancy  40  extends continuously and uniformly (e.g., has uniform dimensions) from the first end  22  to the second end  24  of the cannula  20 , and serves as a fluid channel  60  for delivering fluids between the handle  80  and the second end  24  of the cannula  20 . Because the fluid channel  60  is disposed between two arcuate surfaces  26 ,  28 , the fluid channel  60  itself is arcuate in cross sectional shape. 
     As seen in  FIGS. 5 and 6 , an opening  64  is provided in the second end  24  of the cannula corresponding to the location at which the fluid channel  60  intersects the taper  23  of the second end  24 . As a result, the opening  64  is positioned slightly inward relative to the tip  25 . This position is advantageous, since the opening  64  is not obstructed by tissues when the tip  25  is placed abutting a joint surface. 
     There are many possible configurations of the fluid channel  60 . Some of these possibilities will now be described with reference to  FIGS. 7-10 . In some embodiments, the cannula  20  may include sidewalls  32   a,    32   b  that join respective peripheral side edges  34 ,  35  of the tool-receiving surface  26  and the outer surface  28 . In the embodiment shown in  FIG. 7 , the sidewalls  32   a,    32   b,  the tool-receiving surface  26  and the outer surface  28  are arranged to define a single fluid channel  60 . 
     Referring to  FIGS. 8-10 , in some embodiments, the cannula  20  includes at least one rib  62 . The rib  62  extends radially between the tool-receiving surface  26  and the outer surface  28 . In addition, the rib  62  extends in the axial direction between the first end  22  and second end  24  of the cannula  20 . In some embodiments, the rib  62  extends continuously from the first end  22  to the second end  24 . The rib  62  is a structural member, providing the cannula  20  with increased rigidity, and also maintaining a uniform spacing between the tool-receiving surface  26  and the outer surface  28  along the axial length of the cannula  20 . 
     As shown in  FIG. 8 , a single rib  62  may be disposed between the respective sidewalls  32   a,    32   b  ( FIG. 8 ). In the illustrated embodiment, the single rib  62  is disposed midway between the sidewalls  32   a,    32   b.  The vacancy  40  between sidewalls  32   a,    32   b,  the tool-receiving surface  26  and the outer surface  28  is divided by the rib  62 , thereby defining two fluid channels  60  within the cannula  20 . 
     As shown, for example, in  FIGS. 9 and 10 , more than one rib  62  may be disposed in a spaced-apart manner between the sidewalls  32   a,    32   b.  In some embodiments, the ribs  62  and the respective sidewalls  32   a,    32   b  are equidistantly spaced. For example, in the embodiment illustrated in  FIG. 9 , two ribs  62  are equidistantly spaced between respective sidewalls  32   a,    32   b.  In this case, the vacancy  40  between sidewalls  32   a,    32   b,  the tool-receiving surface  26  and the outer surface  28  is divided by the two ribs  62  so as to define three fluid channels  60  within the cannula  20 . 
     Referring to  FIG. 10 , in some approaches, the cannula  20  is not provided with sidewalls  32   a,    32   b,  but does include at least one rib  62 ; here, in this example, two ribs  62  are provided. In this case, the ribs  62 , the tool-receiving surface  26  and the outer surface  28  define a single fluid channel  60 . 
     The one or more fluid channels  60  provided within the cannula  20  each intersect, and are each in fluid communication with, a handle fluid channel  92  provided within the interior of the handle  80  (discussed below). 
     Referring again to  FIG. 3 , the cannula  20  extends from the handle  80  at an angle θ. For example, in some embodiments, the longitudinal axis  36  of the cannula  20  is angled in the range of 20 to 70 degrees with respect to a longitudinal axis of the handle  80 . In the illustrated embodiment, the longitudinal axis of the cannula is angled at about 45 degrees with respect to a longitudinal axis of the handle  80 . 
     The handle  80  includes an elongate, generally cylindrical body having a first end  82  (for example, the end nearest the user when in use), and a second end  84  opposed to the first end  82 . The cannula  20  is rigidly fixed to the second end  84  of the handle  80 . Although illustrated somewhat schematically here, it is understood that the outer surface  94  of the handle  80  is shaped and/or is provided with a coating or texture which promotes its grippability and user comfort, and provides other ergonomic benefits during long and/or intense use of the device  10 . 
     The handle  80  further includes a handle fluid channel  92  that communicates with the cannula fluid channel  60 . In some embodiments, the handle fluid channel  92  extends within the handle  80  along a longitudinally extending centerline  96 . 
     The handle fluid channel  92  extends inward from the second end  84  to a location between the second end  84  and a mid portion of the handle  80 . For example, as seen in  FIGS. 1-3 ,  11  and  12 , the handle fluid channel  92  extends inward from the second end  84  to a location adjacent to the second end  84 . At least one port  98  is provided within the second end  84  of the handle  80  that permits fluid flow between the handle fluid channel  92  and a connector  86  formed on the outer surface  94  of the handle  80 . In this embodiment, when the device  10  is held by a user, the connector  86  is disposed between the user&#39;s hand and the cannula  20 , and thus is easily accessible by some of the user&#39;s fingers while a grip is maintained on the handle  80 . 
     In some instances, however, it may be more convenient to have a handle  80  in which the connector  86  is disposed at the first end  82  of the handle. For example, as seen in  FIGS. 13 and 14 , an alternative handle  80 ′ is shown in which the handle fluid channel  92 ′ extends from the second end  84 ′ to the first end  82 ′ of the handle  80 ′. In this embodiment, the connector  86  is provided on the end of the handle  80 ′ closest to the user. At least one port  98  is provided at the first end  82 ′ of the handle  80 ′ that permits fluid flow between the handle fluid channel  92 ′ and a connector  86  formed on the outer surface  94 ′ at the first end  82 ′ of the handle  80 ′. In this alternative embodiment, when the device  10 ′ is held by a user, since the connector  86  is disposed on the end of the handle  80 ′ closest to the user, one of the user&#39;s hands grips the handle  80 ′ between the connector  86  and the cannula  20 . In this case, the user would use the other hand to access valves  90  of the connector  86 . 
     The connector  86  may include a removable cap  88 . The cap  88  is tethered to the handle to retain the removed cap  88  within easy reach and to prevent accidental loss of the cap  88 , especially a loss within a surgical incision. The cap  88  is detachably connected to the connector  86  by conventional means such as a press fit or a threaded engagement. 
     The connector  86  may include fluid flow control mechanisms, including but not limited to a simple manual valve  90 , such as a stopcock, actuated by a stem  91 . In addition, the connector  86  may connect to external fluid sources or sinks via conventional means. In some embodiments, the connector  86  includes fittings of the quick connect/disconnect type, such as, but not limited to, a Luer-Lok, which is a registered trademark of Becton Dickinson, Franklin Lakes, N.J., USA. 
     In some approaches, the device  10  is formed of a metal such as stainless steel. In this approach, the device may be re-used in multiple procedures. In other approaches, the device  10  is formed of an inexpensive, rigid material such as plastic. In this approach, the device  10  may be a disposable device such that it is discarded after a single use. 
     The device  10  may be sold as part of a kit. For example, in one type of kit, the kit may include multiple versions of the device  10 , each version having a unique size and/or handle configuration. In another type of kit, the kit may include one or more versions of the device  10  along with other instruments used for a specific surgical procedure. 
     A selected illustrative embodiment of the invention is described above in some detail. It should be understood that only structures considered necessary for clarifying the present invention have been described herein. Other conventional structures, and those of ancillary and auxiliary components of the system, are assumed to be known and understood by those skilled in the art. Moreover, while a working example of the present invention has been described above, the present invention is not limited to the working example described above, but various design alterations may be carried out without departing from the present invention as set forth in the claims.