Abstract:
A system for securing a loading unit to an adapter includes a loading unit, an adapter, and a retention clip. The loading unit includes a shell having a proximal end portion having a radial surface that defines a radial groove. The adapter has a proximal end that is configured to selectively couple to a handle and a distal end that is received within the proximal end portion of the shell. The retention clip is disposed radially about the radial surface of the proximal end portion within the radial groove. The retention clip has a first and a second and a body therebetween. The first end of the body includes a lock that releasably secures the loading unit to the distal end of the adapter.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates generally to surgical stapling instruments. More specifically, the present disclosure relates to circular surgical stapling instruments including replaceable loading units. 
         [0003]    2. Background of Related Art 
         [0004]    Surgical stapling devices configured to join tissue portions during a surgical procedure are well known. These devices include linear end effectors which are oriented parallel or transverse to a longitudinal axis of the device as well as circular end effectors. Typically, linear stapling devices include a disposable loading unit or a replaceable cartridge that allows the stapling device to be used multiple times. However, conventional circular stapling devices include a cartridge or shell assembly that is fixedly attached to the device such that the device must be disposed of after a single use. Some circular stapling devices include a cartridge or shell assembly that is replaceable. 
         [0005]    A need exists in the art for a simple, inexpensive device for releasably securing a cartridge or shell assembly to a circular stapling device to facilitate reuse of the stapling device. 
       SUMMARY 
       [0006]    In an aspect of the present disclosure, a loading unit and locking collar assembly includes a shell assembly and a locking collar. The shell assembly has a proximal end portion for receiving a distal end portion of a surgical instrument. The proximal end portion includes an annular ring that has an outer surface and an inner surface. The outer surface of the annular ring defines an annular groove with the proximal end portion. The annual ring defines a lock opening therethrough. The locking collar is releasably disposed within the annular groove and includes an annular body. The annular body of the locking collar has a pair of release surfaces and a lock. The lock extends radially inward from the annular body. The pair of release surfaces is configured to transition the locking collar from a clocked configuration to an unlocked configuration. In the locked configuration, the lock extends through the lock opening to penetrate the inner surface of the annular ring and in the unlocked configuration the lock is positioned radially outward from the inner surface of the annular ring. 
         [0007]    In aspects, each of the release surfaces is urged towards the other release surface to transition the locking collar from the locked configuration to the unlocked configuration. Each of the release surfaces may be compressed radially inward to transition the locking collar towards the unlocked configuration. Alternatively, each of the release surfaces may be urged about the circumference of the locking collar in a plane transverse to a longitudinal axis of the shell assembly to transition the locking collar towards the unlocked configuration. 
         [0008]    In some aspects, the locking collar defines an elliptical cross-section in a plane transverse to a longitudinal axis of the shell assembly in which the width in the unlocked configuration is less than the width in the locked configuration. The width may be defined between the pair of release surfaces. Alternatively, the locking collar may define an elliptical cross-section in a plane transverse to a longitudinal axis of the shell assembly in which the width is less than the height. 
         [0009]    In certain aspects, the locking collar defines a circular cross-section in a plane transverse to a longitudinal axis of the shell assembly in the locked configuration. The locking collar may define an elliptical cross-section in a plane transvers to a longitudinal axis of the shell assembly in which the width is less than the height in the unlocked configuration. The height may be defined between the pair of release surfaces and the lock. 
         [0010]    In particular aspects, the locking collar is biased towards the locked configuration. The annular body of the locking collar may split to from the first and second release surfaces. The first surface may extend in a first direction about the circumference of the annular body and the second release surface may extend in a second direction opposite the first direction about the circumference of the annular body. The first and second release surfaces may each include an end that defines an engagement window between the end and the annular body. The locking collar may be configured to provide indicia when the locking collar transitions from the unlocked configuration to the locked configuration. The indicia may be audible. The shell assembly may be configured to fire staples through tissue. 
         [0011]    In another aspect of the present disclosure, a surgical system includes a surgical instrument, a loading unit, and a locking collar. The surgical instrument includes a distal end. A loading unit includes a shell assembly that has a proximal end portion positioned over the distal end of the surgical instrument. The proximal end portion includes an annular ring that has an outer surface and an inner surface. The outer surface of the annular ring defines an annular groove with the proximal end portion. The annular ring defines a lock opening therethrough. The locking collar is releasably disposed within the annular groove of the loading unit and includes an annular body that has a pair of release surfaces and a lock. The lock extends radially inward from the annular body. The pair of release surfaces is configured to transition the locking collar from a locked configuration to an unlocked configuration. In the locked configuration the lock extends through the lock opening to penetrate the inner surface of the annular ring and in the unlocked configuration the lock is positioned radially outward from the inner surface of the annular ring. 
         [0012]    In aspects, the distal end of the surgical instrument defines a window. The lock may extend into the window in the locked configuration and may be positioned outside the window in the unlocked configuration. The locking collar may secure the loading unit to the distal end of the surgical instrument in the locked configuration and the locking collar may allow the loading unit to be removed from the surgical instrument in the unlocked configuration. The lock may include a proximal step, a distal step, and an angled surface between the proximal and distal steps. The angled surface may be configured to slide over the distal end portion of the surgical instrument to move the lock radially outward until the lock is positioned within windows defined in the distal end of the surgical instrument. 
         [0013]    Further, to the extent consistent, any of the aspects described herein may be used in conjunction with any or all of the other aspects described herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Various aspects of the present disclosure are described hereinbelow with reference to the drawings, which are incorporated in and constitute a part of this specification, wherein: 
           [0015]      FIG. 1A  is a perspective view of a circular stapling surgical instrument in accordance with the present disclosure with a loading unit releasably coupled to a distal end of the surgical instrument; 
           [0016]      FIG. 1B  is a perspective view of another circular stapling adapter in accordance with the present disclosure with the loading unit of  FIG. 1A  releasably coupled to a distal end of the surgical instrument; 
           [0017]      FIG. 2A  is a perspective view of a loading unit and adapter; 
           [0018]      FIG. 2B  is a perspective view of a shell assembly and locking collar; 
           [0019]      FIG. 3  is an enlarged side view of the distal end of the surgical instrument and loading unit of  FIG. 1A ; 
           [0020]      FIG. 4  is a side cross-sectional view taken along the longitudinal axis of  FIG. 3 ; 
           [0021]      FIG. 5  is an enlarged view of the indicated area of detail of  FIG. 4 ; 
           [0022]      FIG. 6  is a partial cross-sectional view taken along the section line  6 - 6  of  FIG. 4  illustrating showing the distal end of the surgical instrument and the locking collar in the locked configuration; 
           [0023]      FIG. 7  is a partial cross-sectional view similar to  FIG. 6  with the distal end of the adapter and the locking collar in the unlocked configuration with a locked configuration of the locking collar shown in dashed lines; 
           [0024]      FIG. 8  is an enlarged side cross-sectional view similar to  FIG. 5  with the locking collar in the unlocked configuration; 
           [0025]      FIG. 9  is a perspective view of another locking collar in accordance with the present disclosure; 
           [0026]      FIG. 10  is a front view of the locking collar of  FIG. 9  in a locked configuration; 
           [0027]      FIG. 11  is a cross-sectional view taken along the section line  11 - 11  of  FIG. 10 ; and 
           [0028]      FIG. 12  is an end view of the locking collar of  FIG. 9  in an unlocked configuration with a locked configuration of the locking collar shown in dashed lines. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0029]    Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term “proximal” refers to the portion of the device or component thereof that is closest to the clinician and the term “distal” refers to the portion of the device or component thereof that is farthest from the clinician. 
         [0030]    With reference to  FIGS. 1A and 2A , a loading unit  10  is provided in accordance with an embodiment of the present disclosure. The loading unit  10  is configured for selective connection to a powered hand held electromechanical instrument (not shown) via an adapter assembly  100 , having an adapter  102 , of a surgical instrument. Alternatively, the loading unit  10  can be configured for connection directly to a manually actuated handle assembly or stapling instrument  700  ( FIG. 1B ) such as described in U.S. Pat. No. 8,789,737 (“the &#39;737 Patent”), which is incorporated herein by reference. In the illustrated embodiment, the loading unit  10  is releasably coupled to a distal end portion  110  of the adapter  102  and includes a staple cartridge  12  ( FIG. 4 ), a shell assembly  20 , and a locking collar  40 . The loading unit  10  may also include an anvil  400  ( FIG. 1B ). The adapter  102  is configured to translate movement of a stapling instrument, e.g., an electromechanical instrument (not shown), to actuate the staple cartridge  12  to suture and cut tissue (not shown). A proximal end  104  of the adapter  102  is attachable to the stapling instrument to actuate the staple cartridge  12 . It is contemplated that the proximal end  104  of the adapter  102  may be attached to a manually actuated instrument such as described in the &#39;737 Patent to actuate the staple cartridge  12 . 
         [0031]    For a detailed description of the structure and function of an exemplary adapter and loading unit, please refer to commonly owned U.S. Provisional Patent Application Ser. No. 62/066,518, filed on Oct. 21, 2014. For a detailed description of the structure and function of an exemplary electromechanical instrument, please refer to commonly owned U.S. patent application Ser. No. 13/484,975, filed on May 31, 2012, now published as U.S. Patent Publication No. 2012/0253329. Each of these applications is incorporated herein by reference in its entirety. 
         [0032]    Referring to  FIG. 2A , the distal end portion  110  of surgical instrument, e.g., the adapter  102 , defines a window  112 . The window  112  passes through the outer surface of the distal end portion  110  of the adapter  102  and is spaced-apart from a distal end  110   a  of the adapter  102 . 
         [0033]    Referring also to  FIG. 2B , the shell assembly  20  includes a proximal end portion  22  that defines a cylindrical opening  21  ( FIG. 2A ) for receiving the distal end portion  110  of the adapter  102  and a distal end  32  that defines a receptacle  34  for receiving and supporting the staple cartridge  12  ( FIG. 4 ). The proximal end portion  22  of the shell assembly  20  includes a recessed annular ring  23  ( FIG. 2B ) that defines a groove  24  sized to receive the locking collar  40 . In embodiments, the locking collar  40  has a thickness equal to the depth of the groove  24  such that the locking collar  40  forms a continuous or smooth surface with the outer surface of the proximal end portion  22  of the shell assembly  20 . The annular ring  23  defines a lock opening  28  ( FIG. 5 ) that receives a portion of the locking collar  40  as detailed below and defines inner and outer surfaces  23   a,    23   b.    
         [0034]    The proximal end portion  22  of the shell assembly  20  supports a collar retainer  25  that retains the locking collar  40  within the groove  24 . The collar retainer  25  may also be tapered to provide a smooth transition from the outer diameter of the locking collar  40  to the distal end portion  110  of the adapter  102  (or alternatively, the instrument  700   FIG. 1B ). The collar retainer  25  may include locking features  26  ( FIG. 2A ) which secure the collar retainer  25  to the proximal end portion  22  of the shell assembly  20 . It is contemplated that the collar retainer  25  may be secured to the proximal end portion  22  of the shell assembly  20  by any known means including, but not limited to, press-fitting or ultrasonic welding tabs and interlocking structure. It is also contemplated that the collar retainer  25  may be integrally formed with the proximal end portion  22  of the shell assembly  20 . 
         [0035]    With reference to  FIGS. 3-6 , the locking collar  40  includes a generally annular body  42  that is sized to fit within the groove  24  of the proximal end portion  22  of the shell assembly  20  and a lock  44  that extends radially inward from the annular body  42 . The locking collar  40  is positioned about the proximal end portion  22  such that the lock  44  is radially aligned with the lock opening  28 . The lock  44  includes a proximal step  45 , a distal step  48 , and an angled surface  46  positioned between the proximal and distal steps  45 ,  48 . The proximal step  45  extends radially inward a first distance from the longitudinal axis A-A of the shell assembly  20  and the distal step  48  extends radially inward a second distance from the longitudinal axis A-A of the shell assembly  20  less than the first distance. The lock  44  may also include a landing  47  between the angled surface  46  and the distal step  48  that is substantially parallel to the longitudinal axis A-A of the shell assembly  20 . The distal step  48  is positioned to engage a distal wall defining the lock opening  28  of the annular ring  23  of the shell assembly  20 . The proximal step  45  is positioned adjacent a proximal wall of the lock opening  28  to longitudinally fix the locking collar  40  to the proximal end portion  22  of the shell assembly  20 . 
         [0036]    The locking collar  40  is made of a resilient material. For example, the locking collar  12  may be formed of a resilient plastic material using an injection molding process. However, it is contemplated the locking collar  40  may be formed of other suitable materials including, but not limited to, spring steel, stainless steel, or wire. 
         [0037]    With particular reference to  FIG. 6 , the locking collar  40  includes first and second release surfaces  41   a,    41   b  with the lock  44  positioned on the annular body  42  halfway between the first and second release surfaces  41   a,    41   b.  In a locked configuration, the annular body  42  defines a generally elliptical shape where the annular body  42  has a width along a first axis B-B (from the first release surface  41   a  to the second release surface  41   b ) that is greater than its height along a second axis C-C (from the lock  44  to the side opposing the lock  44 ). The annular body  42  is biased towards the locked configuration such that the lock  44  when positioned about the annular ring  23  penetrates the inner surface  23   a  of the annular ring  23  ( FIG. 5 ) and extends into the window  112  of the distal end portion  110  of the adapter  102  to secure the loading unit  10  to the surgical instrument, e.g., the adapter  102 . The annular body  42  is positioned within the groove  24  about the annular ring  23  such that the distal step  48  ( FIG. 5 ) engages a distal wall  112   a  ( FIG. 5 ) defining the window  112  of the adapter  102  to longitudinally fix the shell assembly  20  to the distal end portion  110  of the adapter  102  of the surgical instrument. It will be appreciated that the lock opening  28  of the annular ring  23  of the shell assembly  20  is aligned with the window  112  of the adapter  102  in the locked configuration to permit the lock  44  to pass through the lock opening  28  and the window  112  as detailed above. 
         [0038]      FIGS. 7 and 8  illustrate the locking collar  40  in an unlocked configuration with the annular body  42  defining a generally elliptical shape where the height is greater than the width. The release surfaces  41   a,    41   b  can be manually pressed together to move the locking collar  40  to the unlocked configuration. In the unlocked configuration, the lock  44  is moved radially outward by distance “D” shown in  FIG. 7  such that the lock  44  is positioned radially outward from the inner surface  23   a  of the annular ring  23  ( FIG. 5 ). The distance “D” is greater than the distance that the lock  44  extends into the window  112  of the adapter  102  such that in the unlocked configuration, the loading unit  10  is disengaged and removable from the distal end portion  110  of the adapter  102  when the locking collar  40  is in an unlocked configuration. It is contemplated that the distance “D” may be greater than the second distance that the distal step  48  of the lock  44  extends radially inward such that in the unlocked configuration, the lock  44  is removed from the window  112  of the adapter  102  and the lock opening  28  of the proximal end portion  22  of the shell assembly  20 . As shown, in the unlocked configuration, the height is greater than the width; however, it is contemplated that in the unlocked configuration the width may be greater than the height with the lock  44  moved outward by the distance “D”. 
         [0039]    Referring back to  FIGS. 2-4 , to couple the loading unit  10  to the surgical instrument, e.g., the adapter  102 , the loading unit  10  is aligned with the adapter  102  such that the distal end portion  110  of the adapter  102  is positioned within the cylindrical opening  21  of the proximal end portion  22  with the window  112  of the adapter  102  radially aligned with the lock opening  28  of the annular ring  23  and the lock  44  of the locking collar  40 . The outer surface of the locking collar  44  may include visual or tactile indicia as to the location of the lock  44 . With the loading unit  10  aligned with the adapter  102 , the loading unit  10  is moved proximally over the distal end portion  110  of the adapter  102  until the lock  44  is received within the window  112  of the adapter  102 . It will be appreciated that the lock  44  passes through the lock opening  28  to be received within the window  112  of the adapter  102 . As the loading unit  10  is moved proximally over the distal end  110  of the adapter  102 , the angled surface  46  of the lock  44  engages the distal end portion  110  of the adapter  102  to transition, i.e., perform a camming action to deform, the locking collar  40 , against the natural resilience of the annular body  42 , from the locked configuration towards an unlocked configuration until the window  112  moves into alignment with the lock  44 . When the window  112  moves into alignment with the lock  44 , the lock  44  is snaps into the window  112 . The snapping movement of the locking collar  40  may provide visual or audible indicia that the lock  44  is received within the window  112 . It will be appreciated that the natural resilience of the annular body  42  of the locking collar  40  urges the lock  44  through the window  112  in the adapter  102 . When the lock  44  is positioned within the window  112 , the distal step  48  of the locking collar  40  engages the wall  112   a  of the adapter  102  defining the window  112  to longitudinally secure the shell assembly  20  of the loading unit  10  to the adapter  102 . In addition, when the lock  44  is received within the window  112 , the lock  44  prevents the loading unit  10  from rotating or twisting (i.e., radially secure) relative to the surgical instrument, e.g., the adapter  102 . 
         [0040]    With the loading unit  10  is coupled to the surgical instrument, e.g., the adapter  102 , the surgical instrument and loading unit  10  may be used to perform a surgical procedure. After surgical procedure is completed, the loading unit  10  can be decoupled or detached from the surgical instrument as will be discussed in detail below. With the loading unit  10  is decoupled from the surgical instrument, another loading unit may be coupled to the surgical instrument for continued use in the surgical procedure, the surgical instrument may be sterilized for use in another surgical procedure, or the surgical instrument may be discarded. In addition, the loading unit  10  may be sterilized for use in another surgical procedure or may be discarded. 
         [0041]    To decouple or remove the loading unit  10  from the surgical instrument, e.g., the adapter  102 , the locking collar  40  is transitioned to the unlocked configuration by compressing the first and second release surfaces  41   a,    41   b  towards one another along the first axis B-B, as represented by arrows “F” shown in  FIG. 7 . It is contemplated, that the locking collar  40  may be transitioned to the unlocked configuration by compressing only one of the first and second release surfaces  41   a,    41   b  towards the other release surface  41   a,    41   b  as shown in  FIG. 7 . With the locking collar  40  in the unlocked configuration, the shell assembly  20  can be removed from engagement with the distal end portion  110  of the adapter  102  by moving the shell assembly  20  axially in relation to the adapter  102 . 
         [0042]    Referring now to  FIGS. 9-12 , another locking collar  140  is provided in accordance with the present disclosure and includes a lock  44  and an annular body  142 . The lock  44  of locking collar  140  is substantially similar to the lock  44  of the locking collar  40  as detailed above and will not be discussed further below except for how it relates to locking collar  140 . The annular body  142  of the locking collar  140  is similar to the annular body  42  of the locking collar  40  detailed above, as such only the differences will be detailed below for reasons of brevity. 
         [0043]    The annular body  142  is split at one side to form first and second release surfaces or end portions  144 ,  146  which are moveably positioned in relation to each other such that the diameter of the locking collar  140  can be selectively changed, as described below. The first end portion 144  extends in a first direction about the circumference of the annular body  142  and the second end portion  146  extends in a second direction opposite the first direction about the circumference of the annular body  142 . The first and second release surfaces  144 ,  146  are positioned about the annular body  142  opposing the lock  44 . Each of the first and second end portions  144 ,  146  has an end  145 ,  147  that defines an engagement window  149  adjacent the annular body  142 . Each of the first and second end portions  144 ,  146  has a thickness along the longitudinal axis of the loading unit  10  ( FIG. 1 ) approximately half the thickness of the annular body  142  such that the first and second end portions  144 ,  146  overlap one another about the circumference of the annular body  142 . 
         [0044]    With particular reference to  FIGS. 10 and 12 , the locking collar  140  is formed of a resilient material having a natural resiliency to urge the locking collar  140  towards a locked configuration ( FIG. 10 ). In the locked configuration, the annular body  142  defines a substantially circular cross-section in a plane transverse to the longitudinal axis of the loading unit  10  ( FIG. 1 ). In an unlocked configuration of the locking collar  140  ( FIG. 12 ), the annular body  142  defines a generally elliptical cross-section in a plane transverse to the longitudinal axis of the loading unit  10 . In the unlocked configuration, the lock  44  is moved a distance “E′” away from the first and second end portions  144 ,  146 . The locking collar  140  is transitioned towards the unlocked configuration by urging the ends  145 ,  147  of the first and second end portions  144 ,  146 , respectively, towards one another as represented by the arrows “F.” As the ends  145 ,  147  are urged towards one another, the annular body  142  moves the lock  44  the distance “E” away from the ends  145 ,  147 . The first and second end portions  144 ,  146  may include visual or tactile indicia in the form of arrows ( FIG. 9 ) as to the direction to urge the first and second end portions  144 ,  146  to move the locking collar  140  towards the unlocked configuration. 
         [0045]    While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. For example, in the unlocked position of the lock ring, the lock ring can define a width that is less than the width in the locked position and a height is greater than the height in the locked position. In certain embodiments, other relative dimensions of the lock ring change; a lock ring with a changing aspect ratio can be used. 
         [0046]    Any combination of the above embodiments is also envisioned and is within the scope of the appended claims. The present disclosure is not limited to circular stapling loading units, but has application to loading units for linear stapling or other types of instruments, such as electrocautery or ultrasonic instruments. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope of the claims appended hereto.