Patent Publication Number: US-11660116-B2

Title: Trocar assemblies for adapter assemblies for surgical stapling instruments

Description:
This application claims the benefit of, and priority to, U.S. Provisional Patent Application Nos. 62/834,483, 62/834,486; 62/834,493; 62/834,490; 62/834,502; each of which was filed on Apr. 16, 2019, the entire contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to circular stapling instruments. More particularly, the present disclosure relates to trocar assemblies for use in adapter assemblies for circular stapling instruments. 
     Background of Related Art 
     Surgical instruments for applying staples, clips, or other fasteners to tissue are well known. Typically, endoscopic stapling instruments include an actuation unit, e.g., a handle assembly for actuating the instrument, an elongate shaft for accessing a body cavity, and a tool assembly disposed at a distal end of the elongate shaft. 
     Adapter assemblies used with a circular stapling tool assembly include a trocar assembly for selectively positioning an anvil assembly relative to a cartridge assembly. To facilitate securing the anvil assembly relative to the cartridge assembly, it would be beneficial to have a trocar assembly with a trocar member that may be rotated and/or articulated. 
     SUMMARY 
     According to an aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument, is provided. The trocar assembly includes a housing including a tubular body and defining a longitudinal axis, and a trocar mechanism supported with the housing and movable between a retracted position and an advanced position. The trocar mechanism includes a tubular member and a trocar member rotatably supported on a distal end of the tubular body such that the trocar member may be articulated through a plurality of angles in a plurality rotational orientations relative to the tubular body. 
     The trocar member may include a spherical proximal portion, and a distal portion of the tubular body defines a semi-spherical recess for receiving the spherical proximal portion of the trocar body. 
     The spherical proximal portion of the trocar member may be secured within the semi-spherical recess in the tubular body by a snap ring. 
     A bearing member may be received between the spherical proximal portion of the trocar member and the snap ring to facilitate articulation of the trocar member relative to the tubular member. 
     The spherical proximal portion of the trocar member may define a cylindrical recess. 
     The trocar mechanism may further include a lock member slidably disposed within the distal portion of the tubular member and movable between a locked or distal position and an unlocked or proximal position. The lock member may include a cylindrical body and a locking projection extending distally from the cylindrical body. 
     The locking projection of the lock member may be received within the cylindrical recess of the spherical proximal portion of the trocar member when the lock member is in a locked position, to fix the trocar member in longitudinal alignment with the longitudinal axis of the housing. 
     The spherical proximal portion of the trocar member may include a tapered surface about the cylindrical recess to facilitate receipt of the locking projection within the cylindrical recess. 
     A free end of the locking projection may include a tapered surface to facilitate receipt of the locking projection within the cylindrical recess of the trocar member. 
     The lock member may include a pair of tabs extending radially outwardly from the cylindrical body and the tubular body may define a pair of slots for receiving the pair of tabs of the lock member. 
     The lock member may be movable from the locked position to the unlocked position through engagement with the pair of tabs. 
     The trocar assembly may further include a drive member rotatably supported within the housing and configured to cause longitudinal translation of the trocar mechanism. 
     The drive member may be configured to engage the lock member as the trocar mechanism is moved to the retracted position to move the lock member to the locked position. 
     The trocar assembly may further include a bearing assembly disposed on a proximal end of the housing. 
     According to another aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes a housing including: a tubular body and defining a longitudinal axis; an end cap disposed on a distal end of the tubular body, the end cap including flattened inner surfaces; and a trocar member supported within the housing and received through end cap, the trocar member including flattened surfaces corresponding to the flattened inner surfaces of the end cap and stop surfaces disposed adjacent a proximal end of the flattened surfaces. The trocar member is movable between advanced and retracted positions and is rotationally fixed relative to the end cap through engagement of the flattener surfaces of the trocar member and the flattened inner surface of the end cap. The stop surface of the trocar member engages the end cap to prevent overextension of the trocar member from the housing. 
     According to a further aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes a housing including: a tubular body and defining a longitudinal axis, a proximal portion of the tubular body including a threaded inner surface; a trocar mechanism supported with the housing and movable between a retracted position and an advanced position, the trocar mechanism including a tubular member and a trocar member extending from the tubular member, the tubular member having a proximal section with a threaded inner surface; a drive member rotatably supported within the housing, the drive member including a threaded proximal portion configured for engagement with the threaded inner surface of the housing and a threaded distal portion configured for engagement with the threaded inner surface of the tubular member; and a drive connector in fixed rotational relationship and in dynamic longitudinal relationship with the drive member. 
     The drive connector may be maintained in a proximal position during advancement of the trocar mechanism by a plunger member and a spring. 
     The drive connector may include a seal member, and the drive connector may be biased in a proximal direction by a pressurized fluid. 
     The drive connector may include a detent for engaging a drive shaft of a handle assembly. 
     According to yet another embodiment of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes: a housing including a tubular body and defining a longitudinal axis; a trocar member supported with the housing and movable between a retracted position and an advanced position, the trocar mechanism including a tubular member and a trocar member extending from the tubular member, the tubular member having a proximal section with a threaded inner surface; a drive member rotatably supported within the housing, the drive member including a threaded distal portion configured for engagement with the threaded inner surface of the tubular member, the threaded distal portion defining an annular groove; and a snap ring received within the annular groove, wherein during engagement of the threaded inner surface of the tubular member by the snap ring, the drive member is prevented from further rotation. 
     According to an aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes: a housing including a tubular body and defining a longitudinal axis, the tubular body defining at least one arcuate slot extending circumferentially about a distal portion of the tubular body; an end cap rotatably supported on the proximal portion of the tubular body, the end cap including at least one post configured to be received within the arcuate slot of the tubular body to limit rotation of the end cap; and a trocar mechanism supported with the housing and movable between a retracted position and an advanced position. The trocar mechanism includes a tubular member and a trocar member pivotally secured to the tubular member. The trocar mechanism and the end cap are rotationally fixed relative to one another such that rotation of the end cap along the longitudinal axis causes rotation of the trocar mechanism along the longitudinal axis. 
     According to another aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes: a housing including a tubular body and defining a longitudinal axis; an end cap supported on the proximal portion of the tubular body, the end cap defining a longitudinal passage and including at least a first nub extending radially into the longitudinal passage; and a trocar mechanism supported with the housing and movable between a retracted position and an advanced position. The trocar mechanism includes a tubular member and a trocar member pivotally secured to the tubular member. The tubular member defines at least one flattened portion corresponding to the at least first nub, wherein when the tubular member is received within the longitudinal passage of the end cap, the at least one nub aligns with the at least one flattened portion to permit rotation of the trocar mechanism along the longitudinal axis within the end cap. 
     According to a further aspect of the present disclosure, a trocar assembly for releasable engagement with an adapter assembly of a surgical stapling instrument is provided. The trocar assembly includes: a housing including a tubular body and defining a longitudinal axis, the tubular body defining a longitudinal slot having a narrow proximal portion and a wide narrow portion; and a trocar mechanism supported with the housing and movable between a retracted position and an advanced position. The trocar mechanism includes a tubular member and a trocar member pivotally secured to the tubular member. The trocar mechanism also includes a post extending radially outward from the tubular member, the post being receivable within the longitudinal slot in the housing, wherein the trocar mechanism is permitted to rotate about the longitudinal axis when the post is disposed within the wide distal portion of the longitudinal slot and the trocar mechanism is prevented from rotating when the post is disposed within the narrow proximal portion of the longitudinal slot. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein: 
         FIG.  1    is a perspective view of a surgical stapling instrument including a trocar assembly according to an embodiment of the present disclosure; 
         FIG.  2    is a perspective view of a distal end of the surgical stapling instrument shown in  FIG.  1   , including a loading unit, a trocar assembly, and an anvil assembly; 
         FIG.  3    is a perspective view of the trocar assembly of the adapter assembly shown in  FIG.  1   ; 
         FIG.  4    is a perspective view of a housing assembly and a trocar mechanism of the trocar assembly shown in  FIG.  3   ; 
         FIG.  5    is an exploded perspective view of the trocar mechanism shown in  FIG.  4   ; 
         FIG.  6    is an exploded perspective view of an articulation assembly of the trocar mechanism shown in  FIG.  4   ; 
         FIG.  7    is a perspective end view of a trocar member of the trocar assembly shown in  FIG.  3   ; 
         FIG.  8    is a cross-sectional side view taken along line  8 - 8  shown in  FIG.  4   ; 
         FIG.  9    is an enlarged view of the indicated area of detail shown in  FIG.  8   ; 
         FIG.  10    is a cross-sectional top view taken along line  10 - 10  shown in  FIG.  9   ; 
         FIG.  11    is a cross-sectional view as shown in  FIG.  8   , with the trocar mechanism in an advanced position; 
         FIG.  12    is an enlarged view of the indicated area of detail shown in  FIG.  11   ; 
         FIG.  13    is an enlarged view as shown in  FIG.  12   , with a lock member in a retracted position; 
         FIG.  14    is a perspective view of the trocar assembly shown in  FIG.  3   , with the trocar mechanism in an advanced position; 
         FIG.  15    is a cross-sectional side view taken along line  15 - 15  shown in  FIG.  14   ; 
         FIG.  16    is a perspective view of a trocar assembly according to another embodiment of the present disclosure, with a trocar mechanism in an advanced position; 
         FIG.  17    is a cross-sectional side view taken along line  17 - 17  shown in  FIG.  16   ; 
         FIG.  18    is a perspective view of the trocar mechanism shown in  FIG.  16   ; 
         FIG.  19    is an enlarged view of the indicated area of detail shown in  FIG.  17   ; 
         FIG.  20    is a cross-sectional view as shown in  FIG.  17   , with the trocar mechanism in a retracted position; 
         FIG.  21    is an enlarged view of the indicated area of detail shown in  FIG.  20   ; 
         FIG.  22    is an exploded perspective view of a trocar assembly according to another embodiment of the present disclosure; 
         FIG.  23    is a cross-sectional side view of the trocar assembly shown in  FIG.  22   ; 
         FIG.  24    is an enlarged view of the indicated area of detail shown in  FIG.  23   ; 
         FIG.  25    is a cross-sectional view as shown in  FIG.  23   , with the trocar mechanism in an advanced position; 
         FIG.  26    is an enlarged view of the indicated area of detail shown in  FIG.  25   ; 
         FIG.  27    is an enlarged cross-sectional perspective view of a proximal portion of the trocar assembly shown in  FIG.  22   ; 
         FIG.  28    is a perspective side view of a drive connector of a drive mechanism of the trocar assembly shown in  FIG.  22   ; 
         FIG.  29    is an enlarged cross-sectional perspective view of a proximal portion of a drive assembly according to another embodiment of the present disclosure; 
         FIG.  30    is a perspective side view of a drive connector of the drive assembly shown in  FIG.  29   ; 
         FIG.  31    is an enlarged cross-sectional perspective view of a proximal portion of a drive assembly according to another embodiment of the present disclosure; 
         FIG.  32    is a perspective side view of a drive connector of the drive assembly shown in  FIG.  31   ; 
         FIG.  33    is a perspective side view of a trocar assembly according to yet another embodiment of the present disclosure; 
         FIG.  34    is an enlarged view of the indicated area of detail shown in  FIG.  33   ; 
         FIG.  35    is a perspective side view of a trocar mechanism and a drive member of the trocar assembly shown in  FIG.  33   ; 
         FIG.  36    is an enlarged view of the indicated area of detail shown in  FIG.  36   ; 
         FIG.  37    is a cross-sectional view of the trocar assembly shown in  FIG.  33   , with the trocar mechanism in an advanced position; 
         FIG.  38    is a cross-sectional perspective side view of a distal end of a housing assembly of the trocar assembly shown in  FIG.  33   ; 
         FIG.  39    is a cross-sectional view as shown in  FIG.  36   , with the trocar mechanism in a retracted position; 
         FIG.  40    is an enlarged view of the indicated area of detail shown in  FIG.  39   ; 
         FIG.  41    is a perspective side view of a trocar assembly according to still yet another embodiment of the present disclosure; 
         FIG.  42    is a perspective side view of a distal end of the trocar assembly shown in  FIG.  41   , including a housing assembly and a trocar mechanism extending from the housing assembly; 
         FIG.  43    is a perspective side view of a distal end of the housing assembly shown in  FIG.  42   , with parts separated; 
         FIG.  44    is a perspective side view of a trocar assembly according to another embodiment of the present disclosure; 
         FIG.  45    is an enlarged view of the indicated area of detail shown in  FIG.  44   ; 
         FIG.  46    is a perspective end view of a distal end of a housing assembly of the trocar assembly shown in  FIG.  44   ; 
         FIG.  47    is a perspective end view of an end cap of the housing assembly shown in 
         FIG.  44   ; 
         FIG.  48    is a perspective end view of a tubular body of the housing assembly shown in  FIG.  46   ; 
         FIG.  49    is a perspective end view of a distal end of a trocar assembly according to still another embodiment of the present disclosure; 
         FIG.  50    is a cross-sectional end view taken along line  50 - 50  shown in  FIG.  49   ; 
         FIG.  51    is a perspective end view of the distal end of the trocar assembly as shown in  FIG.  49   , with a trocar mechanism is rotated position; 
         FIG.  52    is a cross-sectional end view taken along line  52 - 52  shown in  FIG.  51   ; 
         FIG.  53    is a side view of a trocar mechanism of a trocar assembly according to an embodiment of the present disclosure; 
         FIG.  54    is a side view of a housing assembly configured for use with the trocar mechanism shown in  FIG.  53   ; 
         FIG.  55    is a cross-sectional end view taken along line  55 - 55  shown in  FIG.  54   ; 
         FIG.  56    is a cross-sectional end view taken along line  56 - 56  shown in  FIG.  54   ; 
         FIG.  57    is a perspective side view of a trocar assembly according to yet another embodiment of the present disclosure; 
         FIG.  58    is a perspective side view of a housing assembly of the trocar assembly shown in  FIG.  57   ; 
         FIG.  59    is a perspective side view of the trocar assembly shown in  FIG.  57   , with a trocar mechanism in a first rotational orientation; 
         FIG.  60    is a perspective side view of the trocar assembly shown in  FIG.  57   , with the trocar mechanism in a second rotational orientation; 
         FIG.  61    is a perspective side view of the trocar assembly shown in  FIG.  57   , with the trocar mechanism in a retracted position; and 
         FIG.  62    is a perspective end view of the housing assembly and a proximal end of the trocar mechanism of the trocar assembly shown in  FIG.  57   , as the trocar mechanism is secured to the housing assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the presently disclosed trocar assemblies will now be 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 is common in the art, the term “proximal” refers to that part or component closer to the user or operator, e.g. surgeon or clinician, while the term “distal” refers to that part or component farther away from the user. 
     Referring initially to  FIG.  1   , an adapter assembly suitable for use with a removable trocar assembly according to an embodiment of the present disclosure, shown generally as adapter assembly  20 , is a component of a surgical stapling instrument  10 . The surgical stapling instrument  10  further includes a powered handle assembly  30 , a loading unit  40 , and an anvil assembly  50 . Although shown and described with reference to surgical stapling instrument  10 , the aspects of the present disclosure may be modified for use with surgical stapling instruments having alternative configurations. For a detailed description of exemplary powered surgical stapling instruments, please refer to commonly owned U.S. Pat. Nos. 9,023,014 and 9,055,943 (“the &#39;014 patent” and “the &#39;943 patent”, respectively), the contents of each of which are incorporated by reference herein in their entirety. 
     The adapter assembly  20  of the surgical stapling instrument  10  will only be described to the extent necessary to fully disclose the aspects of the present disclosure. For a detailed description of exemplary adapter assemblies, please refer to commonly owned U.S. Pat. App. Pub. Nos. 2016/0106406 (“the &#39;406 publication”) and 2017/0086879 (“the &#39;879 publication”), the contents of each of which are incorporated by reference herein in their entirety. 
     With continued reference to  FIG.  1   , the adapter assembly  20  includes a proximal portion  22  configured for operable connection to the handle assembly  30  ( FIG.  1   ) and a distal portion  24  configured for operable connection to the loading unit  40  ( FIG.  1   ). Although shown and described as forming an integral unit, it is envisioned that the proximal and distal portions  22 ,  24  may be formed as separate units that are releasably securable to one another. 
     With additional reference to  FIG.  3   , a removable trocar assembly according to an embodiment of the present disclosure, shown generally as trocar assembly  100 , extends distally from the distal portion  24  of the adapter assembly  20  of the surgical stapling instrument  10 . The trocar assembly  100  is releasably secured within the distal portion  24  ( FIG.  1   ) of the adapter assembly  20 . For a detailed description of an exemplary locking mechanism for securing the trocar assembly  100  within the distal portion  24  of the adapter assembly  20 , please refer to the &#39;879 publication, the content of which was previously incorporated by reference herein. 
     With reference now to  FIGS.  3 - 7   , the trocar assembly  100  of the adapter assembly  20  ( FIG.  2   ) of the surgical stapling instrument  10  includes a housing assembly  110 , a bearing assembly  120  supported on a proximal end of the housing assembly  110 , a trocar mechanism  130  slidably disposed within and extending from the housing  110 , and a drive member  160  rotatably supported within the housing assembly  110  by the bearing assembly  120  for longitudinally moving the trocar mechanism  130  relative to the housing assembly  110 . 
     The housing assembly  110  of the trocar assembly  100  includes a tubular body  112  having proximal and distal portions  112   a ,  112   b . In embodiments, the tubular body  112  defines a pair of notches  111  to facilitate releasable attachment of the trocar assembly  100  within the distal portion  24  ( FIG.  1   ) of the adapter assembly  20  of the surgical stapling instrument  10 . Alternatively, the tubular body  112  of the housing assembly  110  may include tabs, slots and tabs, threading, or other suitable configuration for releasable attachment of the trocar assembly  100  to the adapter assembly  20 . An end cap  114  is disposed on the distal portion  112   b  of the tubular body  112 . The bearing assembly  120  of the trocar assembly  100  is disposed on the proximal portion  112   a  of the tubular body  112 . The bearing assembly  120  and/or the end cap  114  may be secured to the tubular body  112  using adhesive, welding, friction fit, mechanical interface, e.g., threads or bayonet coupling, or in any other suitable manner. 
     The bearing assembly  120  of the trocar assembly  130  is configured to rotatably support the drive member  160 . An exemplary bearing assembly is shown and described in the &#39;406 publication, the content of which was previously incorporated by reference herein. 
     With particular reference now to  FIGS.  4 - 10   , the trocar mechanism  130  of the trocar assembly  100  is configured for longitudinal movement relative to the housing assembly  110  of the trocar assembly  100 . The trocar mechanism  130  includes a tubular member  132  slidably disposed within the housing assembly  110 , a trocar member  134  extending distally from within the tubular member  132 , and an articulation mechanism  140  operably disposed within the tubular member  132  and configured to permit selective articulation of the trocar member  134  relative to the tubular member  132 . 
     The tubular member  132  of the trocar mechanism  130  includes a proximal section  132   a  and a distal section  132   b . The proximal and distal sections  132   a ,  132   b , may be secured together in any suitable manner, including with adhesive, welding, mechanical fasteners or the like. In embodiments, the proximal and distal sections  132   a ,  132   b  of the tubular member  132  are integrally formed. An inner surface  133   a  ( FIG.  8   ) of the proximal section  132   a  of the tubular member  132  is threaded. The threaded inner surface  133   a  is configured to engage a threaded portion  162   c  of the drive member  160 . The distal section  132   b  of the tubular member  132  is configured to operably retain and support a proximal end of the trocar member  134  and the articulation mechanism  140 . More particularly, the distal section  132   b  of the tubular member  132  defines a semispherical recess  131   a  for receiving a spherical portion  134   a  of the trocar member  134  and slots  131   b  ( FIG.  10   ) for receiving tab portions  152  extending outwardly from the lock member  142  of the articulation mechanism  140 . 
     With particular reference to  FIG.  7   , the trocar member  134  includes the spherical portion  134   a , a flanged or intermediate portion  134   b , and a tapered or distal portion  134   c . The spherical portion  134   a  of the trocar member  134  is configured to be received within the semispherical recess  131   a  in the distal section  132   b  of the tubular member  132  of the trocar mechanism  130 . The spherical portion  134   a  defines a cylindrical recess  135  ( FIG.  8   ) extending along a longitudinal axis “x” of the trocar member  134 . As will be described in further detail below, the cylindrical recess  135  in the spherical portion  134   a  of the trocar member  134  receives a locking projection  154  of the lock member  142  of the articulation mechanism  140  to orient and secure the trocar member  134  in a longitudinally aligned configuration. The spherical portion  134   a  of the trocar member  134  includes a tapered surface  135   a  ( FIG.  8   ) formed about an entrance to the cylindrical recess  135  to facilitate receipt of the locking projection  154  of the lock member  142  within the cylindrical recess  135   a . The flanged intermediate portion  134   b  of the trocar member  134  is configured for operable engagement with an anvil assembly, e.g., the anvil assembly  50  ( FIG.  1   ). The tapered distal portion  134   c  of the trocar member  134  is configured for piercing tissue and for facilitating engagement of the trocar member  134  with the anvil assembly  50 . 
     With particular reference now to  FIGS.  5 - 10   , the articulation mechanism  140  of the trocar mechanism  130  includes the lock member  142 , a bearing member  144 , and a snap ring  146 . As shown, the bearing member  144  includes first and second bearing halves  144   a ,  144   b , although other configurations are envisioned. The bearing member  144  of the articulation mechanism  140  rotatably supports the spherical portion  134   a  of the trocar member  134  within semispherical recess  131   a  in the distal section  132   b  of the tubular member  132 , and is operably retained within the semispherical recess  131   a  by the snap ring  146 . 
     The lock member  142  of the articulation mechanism  140  of the trocar assembly  100  is slidably disposed within the distal section  132   b  of the tubular member  132 . The lock member  142  includes a substantially cylindrical body  150 , the tab portions  152  extending radially outwardly from the cylindrical body  150 , and a locking projection  154  extending distally from the cylindrical body  150 . The cylindrical body  150  defines a recess  151  for receiving a distal end of the drive member  160 . The tab portions  152  are received within in the slots  131   b  in the distal section  132   b  of the tubular member  132  of the trocar mechanism  130 , and permit longitudinal movement of the lock member  142  between a locked or initial position ( FIG.  9   ) and an unlocked or retracted position ( FIG.  13   ). The locking projection  154  includes a tapered free end  154   a  configured to facilitate receipt of the locking projection  154  within the cylindrical recess  135  of the spherical portion  134   a  of the trocar member  134 . 
     The drive member  160  of the trocar assembly  100  includes an elongate body  162  having a proximal or engagement portion  162   a , an intermediate bearing portion  162   b , and a threaded or distal portion  162   c . The proximal engagement portion  162   a  of the drive member  160  is configured for operable engagement with a drive screw (not shown) disposed within the adapter assembly  20 . The bearing portion  162   b  of the drive member  160  rotatably engages the bearing assembly  120  to permit rotation of the elongate body  162  about its longitudinal axis. The threaded portion  162   c  operably engages the inner threaded portion  133   a  of the proximal section  132   a  of the tubular member  132  to cause longitudinal movement of the trocar mechanism  130  relative to the housing assembly  110 . 
     The operation of the trocar assembly  100  will now be described with reference to  FIGS.  8 - 15   . Referring initially to  FIGS.  8 - 10   , whether provided to the clinician with the trocar assembly  100  preloaded within the adapter assembly  20  ( FIG.  1   ), or provided to the clinician separate from the adapter assembly  20  and, therefore, requiring loading within the adapter assembly  20 , the trocar assembly  100  is provided to the clinician with the trocar mechanism  130  in a retracted position and the lock member  142  of the articulation mechanism  140  in a locked position. When the trocar mechanism  130  is in the retracted position, a distal end of the drive member  160  is received within the recess  151  formed in the cylindrical body  150  of the lock member  142 . When the lock member  142  of the articulation mechanism  140  is in the locked position, the trocar member  134  is fixed in longitudinal alignment with the elongate body  162  of the drive member  160 . When in the longitudinally fixed position, the trocar member  134  may be used in a traditional manner, e.g., to pierce tissue. 
     Turning to  FIGS.  11  and  12   , rotation of the drive member  160  in a first direction, as indicted by arrow “A” in  FIG.  11   , causes the trocar member  134  to move distally, e.g., advance, as indicated by arrows “B” in  FIG.  11   . During advancement of the trocar member  134 , the lock member  142  remains in the locked position with the locking projection  154  received within the cylindrical opening  135  in the spherical portion  134   a  of the trocar member  134 . In this manner, the trocar member  134  remains in longitudinal alignment with the elongate body  162  of the drive member  160 . In embodiments, the lock member  142  may be keyed to the drive member  160  such that retraction of the drive member  160  causes retraction of the lock member  142 . In this manner, retraction of the drive member  160  would disengage the lock member  142  from the trocar member  134 , thereby permitting articulation of the trocar member  134  relative to the housing assembly  110 . Alternatively, the locking projection  154  may be formed directly on the drive member  162 . 
     Turning to  FIGS.  13 - 16   , to disengage the lock member  142  from the trocar member  134 , the clinician engages the tabs  142   a  of the lock member  142  through slots  131   b  in the distal section  132   b  of the tubular member  132  of the trocar mechanism  130  and moves the lock member  142  in a proximal direction, e.g., retracts, as indicated by arrows “C” in  FIG.  13   , to an unlocked position. Proximal movement of the lock member  142  withdraws the locking projection  154  of the lock member  142  from within the cylindrical opening  135  in the spherical portion  132   a  of the trocar member  132 . 
     When the lock member  142  of the articulation mechanism  140  is in the unlocked position, the trocar member  134  is free to articulate in any direction relative to the end cap  114  of the housing assembly  110 . In this manner, the trocar member  134  may be oriented at any angle relative to the housing assembly  110  ( FIGS.  2  and  14   ), to facilitate attachment of the anvil assembly  50  ( FIG.  2   ) to the trocar member  134 . 
     Subsequent to attaching the anvil assembly  50  to the trocar member  134 , the trocar member  134  is retracted by rotating the drive member  160  in a second, opposite direction. As the trocar member  134  is retracted within the housing assembly  110  of the trocar assembly  100 , the trocar member  134  engages the end cap  114  of the housing assembly  110  to cause the trocar member  134  to realign with the elongate body  162  of the drive member  160 . Continued retraction of the trocar member  134  causes the distal end  162   b  of the elongate body  162  of the drive member  160  to engage the lock member  142 . As the trocar member  134  continues to retract, the locking projection  154  of the lock member  142  engages the spherical portion  134   a  of the trocar member  134 . The tapered surface  135   a  surrounding an open end of the cylindrical recess  135  in the spherical portion  134   a  of the trocar member  134  and the tapered free end  154   a  of the locking projection  154  facilitate receipt of the locking portion  144  of the lock member  142  within the cylindrical recess  135 . 
     As described above, receipt of the locking projection  154  of the lock member  152  within the cylindrical recess  135  in the spherical portion  134   a  of the trocar member  134  fixes the trocar member  134  in longitudinal alignment with the elongate body  162  of the drive member  160 . The surgical stapling instrument  10  ( FIG.  1   ) may then be used to complete the stapling procedure in a traditional manner. 
     With reference now to  FIGS.  16 - 21   , a trocar assembly according to another embodiment of the present disclosure is shown generally as trocar assembly  200 . The trocar assembly  200  is substantially similar to the trocar assembly  100  described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  200  includes a housing assembly  210 , a bearing assembly  220  supported on a proximal end of the housing assembly  210 , a trocar mechanism  230  slidably disposed within the housing assembly  210 , and a drive member  260  rotatably supported within the housing assembly  210  by the bearing assembly  220  for longitudinally moving the trocar mechanism  230  relative to the housing assembly  210 . 
     The trocar mechanism  230  of the trocar assembly  200  is configured for longitudinal movement relative to the housing assembly  210  of the trocar assembly  200 . The trocar mechanism  230  is secured within a tubular body  212  of housing assembly  210  by an end cap  214 . The end cap  214  includes flattened inner surfaces  214   a  ( FIG.  19   ). The trocar mechanism  230  includes a tubular member  232  slidably disposed within the housing assembly  210  and a trocar member  234  secured to and extending distally from the tubular member  232 . 
     As shown, the tubular member  232  of the trocar mechanism  230  includes proximal and distal sections  232   a ,  232   b . It is envisioned that the tubular member  232  may be monolithic. The tubular member  232  includes elongate flattened surfaces  231   a  extending along opposed lengths of the tubular member  232  and a stop surface  231   b  ( FIG.  19   ) disposed adjacent the proximal ends of the elongate flattened surfaces  231   a . The elongate flattened surfaces  231   a  of the tubular member  232  of the trocar mechanism  230  align with flattened inner surfaces  214   a  of the end cap  214  of a housing assembly  210  to maintain the trocar member  232  in a fixed rotational orientation relative to the housing assembly  210 . 
     With particular reference to  FIG.  19   , the stop surface  231   b  of the tubular member  232  of the trocar mechanism  230  engages the end cap  214  of the housing assembly  210  during longitudinal movement of the trocar mechanism  230  relative to the housing assembly  210 , e.g., advancement. Engagement of the stop surfaces  231   b  of the tubular member  232  with the end cap  214  retains the trocar mechanism  230  within the housing assembly  210  and prevents over extension of the trocar member  234  from the housing assembly  210 . 
     With particular reference to  FIG.  21   , a proximal facing surface  233  of the tubular member  232  of the trocar assembly  200  is configured to engage a stop member  222  disposed between the tubular body  212  of the housing assembly  210  and the bearing assembly  220  of the housing assembly  210 . In embodiments, the stop member  222  includes a snap ring. The stop member  222  limits the proximal movement of the trocar mechanism  230  to prevent over-retraction of the trocar mechanism  230  within the housing assembly  210 . 
     With reference now to  FIGS.  22 - 28   , a trocar assembly according to another embodiment of the present disclosure is shown generally as trocar assembly  300 . The trocar assembly  300  is substantially similar to the trocar assemblies  100 ,  200  described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  300  includes a housing assembly  310 , a trocar mechanism  330  slidably disposed within the housing  310 , and a drive assembly  360  rotatably supported within the housing assembly  310  for longitudinally moving the trocar mechanism  330  relative to the housing assembly  310 . 
     The housing assembly  310  of the trocar assembly  300  includes a tubular body  312  and an end cap  314  disposed on a distal portion  312   b  of the tubular body  312 . A proximal portion  312   a  of the tubular body  312  includes a threaded inner surface  316  ( FIG.  24   ). As will be described in further detail below, the threaded inner surface  316  of the tubular body  312  engages a threaded proximal portion  362   a  of the drive member  362  of the drive assembly  360  to cause longitudinal translation of the drive member  362  relative to the housing assembly  310 . 
     The trocar mechanism  330  of the trocar assembly  300  is configured for longitudinal movement relative to the housing assembly  310  of the trocar assembly  300 . The trocar mechanism  330  is secured within a tubular body  312  of housing assembly  310  by the end cap  314  on the distal portion  312   b  of the tubular body  312  and the drive assembly  360  on the proximal portion  312   a  of the tubular body  312 . The trocar mechanism  330  includes a tubular member  332  slidably disposed within the housing assembly  310  and a trocar member  334  secured to and extending distally from the tubular member  332 . 
     The drive assembly  360  of the trocar assembly  300  includes the drive member  362 , a drive connector  364  extending from a threaded proximal portion  362   a  of the drive member  362 , a plunger member  366  slidably disposed within the drive connector  364 , and a spring member  368  biasing the plunger member  366 . The plunger member  366  and the spring member  368  operate to maintain the drive connector  364  in a proximal position, e.g., in engagement with a drive shaft (not shown) within the adapter assembly  20  ( FIG.  1   ). 
     The drive member  362  of the drive assembly  360  includes the threaded proximal portion  362   a  and a threaded distal portion  362   b . The threaded proximal portion  362   a  is threaded in a first direction and the threaded distal portion  362   b  is threaded in a second direction. As noted above, the threaded proximal portion  362   a  of the drive member  362  is configured to engage the threaded inner surface  316  of the tubular body  312  of the housing assembly  310 . Rotation of the drive connector  364  causes longitudinal movement of the drive member  362  relative to the housing assembly  310 . The threaded distal portion  362   b  of the drive member  362  engages a threaded inner surface  333  of a proximal portion  332   a  of the tubular member  332 . Rotation of the drive member  362  causes longitudinal movement of the trocar mechanism  330  relative to the housing assembly  310 . 
     A pitch of the threaded proximal portion  362   a  of the drive member  362  may be the same or different from a pitch of the threaded distal portion  362   b . By varying the pitch of the threaded proximal and distal portions  362   a ,  362   b  of the drive member  362 , the rate at which the respective drive member  362  and the trocar mechanism  330  move in the longitudinal direction may be varied. In embodiments, the threaded distal portion  362   b  of the drive member  362  is more coarse (e.g., relatively larger thread pitch) to move the trocar mechanism  330  further while the threaded proximal portion  362   a  is more fine (e.g., relatively smaller thread pitch) for use in both displacing and axial retaining the drive member  362  to the tubular body  312  of the housing assembly  310 . 
     The threaded proximal portion  362   a  of the drive member  362  of the drive assembly  360  defines a cylindrical recess  363  for receiving the drive connector  364 , the plunger member  366 , and the spring member  368 . A washer  365  defines a rectangular opening  365   a  ( FIG.  22   ) is welded or otherwise fixedly secured to the threaded proximal portion  362   a  of the drive member  362  within the cylindrical recess  363  to maintain a flanged distal end  364   a  of the drive connector  364  within the cylindrical recess  363  and to rotationally fix the plunger member  366  relative to the drive member  362 . More particularly, a proximal portion  364   a  of the drive connector  364  includes a rectangular profile that is slidingly received through rectangular opening  365   a  of the washer  365 . In this manner, rotation of the drive connector  364  causes rotation of the drive member  362 . 
     As noted above, the plunger member  364  includes the proximal portion  364   a  that includes a rectangular profile and a distal portion  364   b  that is flanged. The rectangular profile of the proximal portion  364   a  rotationally fixes the drive connector  364  relative to the drive member  362  and the flange of the distal portion  364   b  retains the drive connector  364  within the cylindrical recess  363  of the drive member  362 . The drive connector  364  defines a longitudinal cavity  367  for receiving the spring member  368  received about the plunger member  366 . The spring member  366  is maintained about the plunger member  366  by a flanged distal portion  366   b  of the plunger member  366 . The spring member  368  is configured to bias the plunger member  366  distally, or more particularly, to bias the drive connector  364  proximally. The plunger member  366  and the spring member  368  operate to maintain the drive connector  364  in a proximal position to ensure engagement of the drive connector  364  with a drive shaft (not shown) of the adapter assembly  20  ( FIG.  1   ). 
     With particular reference to  FIGS.  23  and  24   , the trocar mechanism  330  of the trocar assembly  300  is shown in a retracted or distal position. When in the retracted position, the trocar mechanism  330  is disposed adjacent a distal end of the threaded proximal portion  362   a  of the drive member  362  and a proximal end of the threaded proximal portion  362   a  of the drive member  362  engages a washer  318  secured within the proximal end of the tubular body  312  of the housing assembly  310  to retain the drive member  362  within the tubular body  312 , and to act as a stop for the drive member  312  to prevent over-retraction of the drive member  312  within the housing assembly  310 . 
     Turning to  FIGS.  25  and  26   , rotation of the drive connector  364  of the drive assembly  360  in a first direction, as indicated by arrow “A” in  FIG.  26   , causes corresponding rotation of the drive member  362  in the same, first direction. Rotation of the drive member  362  causes longitudinal movement of the drive member  362  in a distal direction, e.g., advancement, as indicated by arrow “B” in  FIG.  26   . Rotation of the drive member  362  in the first direction also causes longitudinal movement of the trocar mechanism  330  in a distal direction, as indicated by arrow “C” in  FIG.  25   . As the drive member  362  moves distally within the housing assembly  310 , the spring member  368  of the drive assembly  360  biases the drive connector  364  proximally to maintain the drive connector  364  in the proximal position in engagement with the drive shaft (not shown) of the adapter assembly  20  ( FIG.  1   ). 
     The trocar mechanism  330  is returned to the retracted position by rotating the drive connection in a second, opposite direction. 
     With reference to  FIGS.  29  and  30   , in another embodiment of trocar assembly  300 , the drive connector  364 , the plunger member  366 , and the spring member  368  are replaced by a single piston member  364 ′. The piston member  364 ′ includes a flanged distal portion  364   b ′ having a seal member  365 ′ received thereabout. The seal member  365 ′ creates a fluid tight seal between the flanged distal portion  364   b ′ of the piston member  364 ′ and the drive member  362 . A pressurized fluid received within the cylindrical recess  363  of the drive member  362  biases the piston member  364 ′ proximally during longitudinal movement of the drive member  362  to maintain the piston member  364 ′ in contact with the drive shaft (not shown) of the adapter assembly  20  ( FIG.  1   ). 
     With reference to  FIGS.  31  and  32   , in another embodiment of trocar assembly  300 , the plunger member  366  and the spring member  368  are replaced by a drive connector  364 ″ having detents  365 ″ on a proximal portion  364   a ″ of the drive connector  364 ″. The detent  365 ″ engages the drive shaft (not shown) of the adapter assembly  20  ( FIG.  1   ) to maintain engagement of the drive connector  364 ″ with the drive shaft. Although shown including more than one detent  365 ″, it is envisioned that the proximal portion  364   a ″ of the drive connector  364 ″ may include only one detent  365 ″. It is further envisioned that the drive connector  364 ″ may be secured to the drive shaft in other suitable manners, e.g., friction fit, bayonet coupling, mechanical fasteners. 
     With reference now to  FIGS.  33 - 40   , a trocar assembly according to another embodiment of the present disclosure is shown generally as trocar assembly  400 . The trocar assembly  400  is substantially similar to the trocar assemblies  100 ,  200 ,  300  described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  400  includes a housing assembly  410 , a bearing assembly  420  supported on a proximal end of the housing assembly  410 , a trocar mechanism  430  disposed within the housing  410 , and a drive member  460  rotatably supported within the housing assembly  410  by the bearing assembly  420  for longitudinally moving the trocar assembly  430  relative to the housing assembly  410 . 
     The trocar mechanism  430  of the trocar assembly  400  is configured for longitudinal movement relative to the housing assembly  410  of the trocar assembly  400 . The trocar mechanism  430  includes a tubular member  432  slidably disposed within the housing assembly  410  and a trocar member  434  extending distally from the tubular member  432 . The tubular member  432  defines an opening  433  that provides access to a distal portion  462   a  of an elongate body  462  of the drive member  460 . The tubular member  432  includes a threaded inner surface  436  ( FIG.  38   ) that engages a threaded distal portion  462   b  of the drive member  462 . 
     The drive member  460  includes the elongate body  462  including a proximal portion  462   a  and the threaded distal portion  462   b . The threaded distal portion  462   b  of the elongate body  462  is configured to engage a snap ring  464 . More particularly, the distal portion  462   b  of the elongate body  462  defines a groove  463  for receiving the snap ring  464 . Although shown including a snap ring  464 , it is envisioned that the distal portion  462   b  of the elongate body  462  may instead be configured to receive a pin, cap or nut that may be bonded, welded, staked or otherwise secured to the drive member  462 . Alternatively, the threads of the distal portion  462   b  of the elongate body  462  of the drive member  460  may be deformed. 
     With reference to  FIGS.  37  and  38   , during advancement of the trocar mechanism  430 , the snap ring  464  engages the threaded inner surface  436  of the tubular member  432  of the trocar mechanism  430  to prevent continued advancement of the trocar mechanism  430 . This configuration contains axial loads within the trocar mechanism  430  and the drive member  460 . In this manner, the housing assembly  410  of the trocar assembly  400  does not experience an axial load, and therefore does not need to be designed stronger. 
     When the snap ring  464  engages the threaded inner surface  436  of the tubular member  432 , a torque spike in motors of the handle assembly  30  ( FIG.  1   ) will indicate to the handle assembly  30  a distal home position for the trocar mechanism  430 . This configuration allows a clinician to calibrate the handle assembly  30  without having to completely retract a previously extended trocar mechanism  430 . 
     With reference to  FIGS.  39  and  40   , a proximal facing surface  433  of the tubular member  432  of the trocar assembly  400  is configured to engage a stop member  422  disposed between the tubular body  412  of the housing assembly  410  and the bearing assembly  420  of the housing assembly  410 . In embodiments, the stop member  422  includes a snap ring. The stop member  422  limits the proximal movement of the trocar mechanism  430  to prevent over-retraction of the trocar mechanism  230  within the housing assembly  410 . 
     Embodiments of trocar assemblies having a trocar mechanism that includes a trocar member configured for articulation and rotation of a trocar member will be described with reference to  FIGS.  42 - 61   . Referring initially to  FIGS.  41 - 44   , an embodiment of a trocar assembly according to an embodiment of the present disclosure is shown generally as trocar assembly  500 . The trocar assembly  500  is substantially similar to the trocar assembly  100  described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  500  includes a housing assembly  510 , a bearing assembly  520  supported on a proximal end of the housing assembly  510 , a trocar mechanism  530  slidably disposed within the housing assembly  510 , and a drive member  560  rotatably supported within the housing assembly  510  by the bearing assembly  520  for longitudinally moving the trocar mechanism  530  relative to the housing assembly  510 . 
     The housing assembly  510  includes a tubular body  512 , and an end cap  514  operably supported on a distal portion  512   b  of the tubular body  512 . More particularly, the distal portion  512   a  of the tubular body  512  defines a cutout  513   a  and an arcuate slot  513   b . The cutout  513   a  facilitates connection of the end cap  514  to the tubular body  512  and the arcuate slot  513   b  receives a post  516  of the end cap  514 . The end cap  514  includes a substantially annular body  514   a  including opposed flattened inner surfaces  514   b  configured to rotationally fix the trocar mechanism  530  relative to the end cap  514 . As will be described in further detail below, the end cap  514  is configured to receive the trocar mechanism  530  therethrough and permit rotation of the trocar mechanism  530  relative to the tubular body  512 . 
     The trocar mechanism  530  of the trocar assembly  500  is configured for longitudinal and rotational movement and articulation relative to the housing assembly  510  of the trocar assembly  500 . The trocar mechanism  530  is prevented from overextending from the tubular body  512  of housing assembly  510  by the end cap  514 . The trocar mechanism  530  includes a tubular member  532  slidably disposed within the housing assembly  510 , and a trocar member  534  pivotally secured to and extending distally from the tubular member  532 . 
     As shown, the tubular member  532  of the trocar mechanism  530  includes proximal and distal sections  532   a ,  532   b . It is envisioned that the tubular member  532  may be monolithic. The tubular member  532  includes elongate flattened surfaces  531   a  extending along opposed lengths of the tubular member  532 . The elongate flattened surfaces  531   a  of the tubular member  532  of the trocar mechanism  530  align with flattened surfaces  514   b  of the end cap  514  of a housing assembly  510 . The elongate flattened surfaces  531   a  of the tubular member  532  and the flattened surfaces  514   a  of the end cap  514  operate together to maintain the trocar member  532  in a fixed rotational orientation relative to the end cap  514 . 
     As noted above, the end cap  514  includes the post  516  received within the arcuate slot  513   b  in the distal portion  512   b  of the tubular body  512  of the housing assembly  510 . The end cap  514  is configured to rotate about a longitudinal axis “x” of the trocar assembly  500 . The rotation of the end cap  514 , and therefore rotation of the trocar mechanism  530  received through the end cap  514 , is limited by a length of the arcuate slot  513   b . The greater the length of the arcuate slot  513   b , the greater the degree of rotation of the end cap  514  and the trocar mechanism  530  received through the end cap  514 . 
     Turning to  FIGS.  44 - 48   , another embodiment of a trocar assembly is shown generally as trocar assembly  600 . The trocar assembly  600  is substantially similar to the trocar assembly  500  described above, and will only be described in detail as it relates to the differences therebetween. 
     A housing assembly  610  of the trocar assembly  600  includes a tubular body  612 , and an end cap  614  operably supported on a distal portion  612   b  of the tubular body  612 . More particularly, the distal portion  612   b  of the tubular body  612  defines a pair of arcuate slots  613 . The arcuate slots  613  receive posts  616  of the end cap  614 . The end cap  614  includes a substantially annular body  614   a  including opposed flattened inner surfaces  614   b.    
     With particular reference to  FIG.  46   , the posts  616  are secured to the end cap  614  subsequent to the end cap  614  being received within the distal portion  612   b  of the tubular body  612  of the housing assembly  610 . More particularly, the posts  616  are welded, glued, mechanically fastened, or otherwise secured to the annular body  614   a  of the end cap  614  after the annular body  614   a  of the end cap  614  is received with the distal portion  612   b  of the tubular body  612 . In this manner, the posts  616  operate to retain the end cap  614  within the tubular body  612  and to permit rotation of the end cap  614  about a longitudinal axis “x” of the trocar assembly  630 . 
     Referring now to  FIGS.  49 - 52   , an embodiment of a trocar assembly according to still another embodiment of the present disclosure is shown generally as trocar assembly  700 . The trocar assembly  700  is substantially similar to the trocar assemblies  500 ,  600  described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  700  includes a housing assembly  710 , and a trocar mechanism  730  slidably disposed within the housing assembly  710 . 
     The housing assembly  710  includes a tubular body  712 , and an end cap  714  supported on a distal portion  712   b  of the tubular body  712 . The end cap  714  includes a substantially annular body  714   a  including a pair of nubs  716  extending from an inner surface  714   b  of the annular body  714   a . As will be described in further detail below, the nubs  716  of the end cap  714  correspond with elongated flattened surfaces  731  of the tubular member  732  of the trocar mechanism  730  to permit and limit rotation of the trocar mechanism  730  about a longitudinal axis “x” of the trocar assembly  700  relative to the tubular body  712  of the housing assembly  710 . 
     The trocar mechanism  730  of the trocar assembly  700  is configured for longitudinal and rotational movement and articulation relative to the housing assembly  710  of the trocar assembly  700 . The trocar mechanism  730  includes the tubular member  732  slidably disposed within the housing assembly  710  and a trocar member  734  pivotally secured to and extending distally from the tubular member  732 . 
     The tubular member  732  of the trocar mechanism  730  includes the elongate flattened surfaces  731   a  extending along opposed lengths of the tubular member  732 . The elongate flattened surfaces  731  of the tubular member  732  align with and correspond to the nubs  716  of the end cap  714  of a housing assembly  710 . The elongate flattened surfaces  731  of the tubular member  732  provide a clearance that permits reception of the tubular member  732  through the end cap  714 . The tubular member  732  is movable from a first rotational orientation relative to the end cap  714  ( FIG.  50   ) to a second rotational orientation relative to the end cap  714  ( FIG.  52   ). Engagement of the nubs  716  of the end cap  714  with the tubular member  732  of the trocar mechanism  730  limits the rotation of the tubular member  732  about the longitudinal axis “x” of the trocar assembly  700 . 
     With reference now to  FIGS.  53 - 56   , in another embodiment of the present disclosure, a trocar mechanism  830  includes a tubular member  832  that is slidably receivable with a tubular body  812  of a housing assembly  810 . The trocar mechanism  830  includes a pin or post  836  extending outwardly from the tubular member  832 . The pin  836  is configured to be received within a longitudinal slot  813  formed in the tubular body  812  of the housing assembly  810 . 
     With particular reference to  FIG.  54   , the longitudinal slot  813  in the tubular body  812  of the housing assembly  810  includes a narrow proximal portion  813   a  and a wide distal portion  813   b . The longitudinal slot  813  is configured to receive the pin  836  of the trocar mechanism  830  when the trocar mechanism  830  is received within the tubular body  812 . 
     Turning to  FIG.  55   , when the pin  836  of the tubular member  832  of the trocar mechanism  830  is received within the tubular body  812  of the housing assembly  810 , the trocar mechanism  830  is prevented from rotating through engagement of the pin  836  with the walls of the tubular body  812  defining the narrow proximal portion  813   a  of the longitudinal slot  813 . Conversely, the trocar mechanism  830  is permitted to rotate because of the spacing between the walls of the tubular body  812  defining the wide distal portion  813   b  of the longitudinal slot  813 . In this manner, when the trocar mechanism  830  is in a retracted position within the tubular body  812  of the housing assembly  810 , e.g., when the pin  836  is disposed within the narrow proximal portions  813   a  of the longitudinal slot  813  ( FIG.  55   ), the trocar mechanism  830  is fixed from rotational movement, and when the trocar mechanism is in an advanced position within the tubular body  812 , e.g., when the pin  836  is disposed within the wide proximal portion  813   b  of the longitudinal slot  813  ( FIG.  56   ), the trocar mechanism  830  is free to rotate relative to the tubular body  812 . 
     With reference to  FIGS.  57 - 62   , a trocar assembly according to still yet another embodiment of the present disclosure is shown generally as trocar assembly  900 . The trocar assembly  900  is similar to the trocar assemblies described hereinabove, and will only be described in detail as it relates to the differences therebetween. 
     The trocar assembly  900  includes a housing assembly  910 , a trocar mechanism  930  slidably disposed within the housing assembly  910 , and a drive member  960  rotatably supported within the housing assembly  910  by the bearing assembly  920  for longitudinally moving the trocar mechanism  930  relative to the housing assembly  910 . 
     With particular reference to  FIG.  58   , the housing assembly  910  of the trocar assembly  900  includes a tubular body  912 . The tubular body  912  includes a longitudinal cutout  913  having a narrow proximal portion  913   a , a tapered intermediate portion  913   b , and a wide distal portion  913   c . As will be described in further detail below, the longitudinal cutout  913  permits rotation of the trocar mechanism  930  along a longitudinal axis “x” of the trocar assembly  900 . A distal portion  912   b  of the tubular body  912  defines a notch  915  to facilitate loading of the trocar mechanism  930  within the tubular body  912  of the housing assembly  910 . 
     The trocar mechanism  930  of the trocar assembly  900  is configured for longitudinal and rotational movement relative to the housing assembly  910  of the trocar assembly  900 . The trocar mechanism  930  includes a tubular member  932  slidably disposed within the housing assembly  910  and a trocar member  934  secured to and extending distally from the tubular member  932 . The trocar mechanism  930  is secured within a tubular body  912  of housing assembly  910  by pin or post  936  extending outwardly from the tubular body  912 . The pin  936  is configured to be received within the longitudinal slot  913  of the tubular body  912 . 
     The drive member  960  of the trocar assembly  900  includes an elongate body  962  having a threaded or distal portion  962   b . The threaded portion  962   b  threadingly engages the tubular member  932  of the trocar mechanism  930 . Engagement of the tubular member  932  of the trocar mechanism  930  by the elongate body  962  of the drive member  960  secures the trocar mechanism  930  within the tubular body  912  of the housing assembly  910 . 
     As shown in  FIGS.  59  and  60   , when the trocar mechanism  930  is in an extended or advanced position, the pin  936  extending from the tubular member  932  of the trocar mechanism  930  is disposed within the wide distal portion  913   c  of the longitudinal slot  913  in the tubular body  912  of the housing assembly  910 . When the pin  936  is disposed within the wide distal portion  913   c  of the longitudinal slot  913 , the trocar mechanism  930  is permitted to rotate about a longitudinal axis “x” of the trocar assembly  900  from a first position ( FIG.  59   ) to a second position ( FIG.  60   ). 
     As the trocar mechanism  930  is retracted within tubular body  912  of the housing assembly  910 , e.g., as the drive member  960  rotates in a first direction, the pin  936  of the trocar mechanism  930  passes the tapered intermediate portion  913   b  of the longitudinal slot  913  and is directed into the narrow proximal portion  913   a  of the longitudinal slot  913 . When the pin  936  is disposed within the tapered intermediate portion  913   b  of the longitudinal slot  913 , the degree of rotation of the trocar mechanism  930  is limited by the walls of the tubular body  912  defining the longitudinal slot  913 . When the pin  936  of the trocar mechanism  930  is received within the narrow proximal portion  913   a  of the longitudinal slot  913 , the trocar mechanism  930  is prevented from rotating about the longitudinal axis “x”. 
     Referring now to  FIG.  62   , the tubular body  912  of the housing assembly  910  is shown as the tubular member  932  of the trocar mechanism  930  is received through the notch  915  ( FIG.  58   ) in the distal portion  912   b  of the tubular body  912 . After receiving the tubular member  932  of the trocar mechanism  930  through the notch  915 , the tubular member  932  is aligned with and engaged to the drive member  960  and is threadingly engaged by the drive member  960  to retain the trocar mechanism  930  within the tubular body  912  of the housing assembly  910 . The trocar assembly  900  then operates in a traditional manner. 
     It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances. The embodiments described with reference to the attached drawing figures are presented only to demonstrate certain examples of the disclosure. Other elements, steps, methods and techniques that are insubstantially different from those described above and/or in the appended claims are also intended to be within the scope of the disclosure.