Patent Publication Number: US-2021169457-A1

Title: Robotic surgical systems and instrument drive assemblies

Description:
BACKGROUND 
     Robotic surgical systems have been used in minimally invasive medical procedures. Some robotic surgical systems include a console supporting a robot arm, and at least one end effector such as forceps or a grasping tool that is mounted to the robot arm via a wrist assembly. During a medical procedure, the end effector and the wrist assembly are inserted into a small incision (via a cannula) or a natural orifice of a patient to position the end effector at a work site within the body of the patient. 
     In prior robotic surgical systems, cables extend from the robot console, through the robot arm, and connect to the wrist assembly and/or end effector. In some instances, the cables are actuated by means of motors that are controlled by a processing system including a user interface for a surgeon or clinician to be able to control the robotic surgical system including the robot arm, the wrist assembly and/or the end effector. 
     Prior to or during use of the robotic system, surgical instruments are selected and connected to an instrument drive assembly of each robot arm. For proper installation to be completed, certain connecting features of the surgical instrument must be matingly engaged to corresponding connecting features of the instrument drive assembly. Once these features are matingly engaged, the instrument drive assembly can drive the actuation of the surgical instrument. Accordingly, there is a need for instrument drive assemblies that not only provide quick and easy mechanical and electrical engagement with surgical instruments, but provide a means to couple to a variety of surgical instruments having unique end effectors attached thereto. 
     SUMMARY 
     The present disclosure relates to an instrument drive assembly including a housing assembly, a coupling tube, a coupling assembly, and a retention mechanism. The housing assembly supports a drive assembly therein. The coupling tube is supported at a distal end of the housing assembly and extends distally therefrom. The coupling assembly is supported in the housing assembly and is configured to releasably couple to an instrument drive shaft of a surgical instrument. The retention mechanism is configured to releasably couple to an instrument sleeve of the surgical instrument. 
     In an embodiment, the retention mechanism is supported in the housing assembly and includes a button and a latch plate. The button is slidably coupled to the housing assembly between first and second positions, and including a cam arm. The latch plate is rotationally coupled to the housing assembly and configured to transition between a locked configuration and unlocked configuration, with respect to an instrument sleeve of the surgical instrument. The latch plate includes an arm configured to engage the cam arm of the button and a portion of an instrument sleeve of the surgical instrument. In the first position of the button, the arm of the latch plate is configured to engage a portion of an instrument sleeve of the surgical instrument. In the second position of the button, the cam arm of the button engages the arm of the latch plate such that the latch plate is configured to pivot out of engagement with a portion of an instrument sleeve of the surgical instrument. 
     In a further embodiment, the retention mechanism includes a first biasing member interposed between the latch plate and the housing assembly, such that the latch plate is biased into one of the locked or unlocked configurations. In an embodiment, the retention mechanism includes a second biasing member interposed between the button and the housing assembly, such that the button is biased into one of the first or second positions. 
     In yet another embodiment, the coupling assembly includes a drive link pivotably coupled to the housing assembly and a drive screw of the drive assembly. In a further embodiment, proximal and distal translation of the drive screw, with respect to the housing assembly, pivots the drive link between a locked position and an unlocked position. 
     In yet a further embodiment, the drive link defines a receiving region thereon. The receiving region includes a cavity, a port, and a channel. The cavity is defined within the receiving region and is configured to receive a proximal portion of an instrument drive shaft of the surgical instrument therein. The port extends into the cavity and is configured to receive a proximal portion of an instrument drive shaft of the surgical instrument therethrough. The channel extends along the cavity and is configured to receive a portion of an instrument drive shaft of the surgical instrument distal of a proximal portion of the instrument drive shaft of the surgical instrument therein. The receiving region of the drive link is configured to releasably couple a proximal portion of an instrument drive shaft of the surgical instrument to the drive link. 
     Further still, in an embodiment, in the unlocked position of the drive link, the drive screw of the drive assembly is in a distal most position and the drive linked is angled an amount sufficient such that the port of the receiving region of the drive link is oriented to fully receive the proximal portion of an instrument drive shaft. In the locked position of the drive link, the drive screw of the drive assembly is in a position proximal of the distal most position and the port of the receiving region defines an angle with respect to the longitudinal axis of the coupling tube. 
     In yet a further embodiment, in the locked position of the drive link, the cavity of the receiving region is configured to retain therein a proximal portion of an instrument drive shaft of the surgical instrument and the channel of the receiving region is configured to receive therein a portion of an instrument drive shaft of the surgical instrument distal of a proximal portion of an instrument drive shaft of the surgical instrument. 
     In another embodiment, the drive assembly includes an engagement assembly, whereby the engagement assembly includes a coupling rod, a proximal gear, and a distal gear. The coupling rod includes a proximal portion, a distal portion, and a longitudinal axis defined through a radial center thereof. The proximal gear is disposed at the proximal portion of the coupling rod and is rotationally fixed thereto. The distal gear is disposed at the distal portion of the coupling rod and is rotationally fixed thereto. 
     In a further embodiment, the drive assembly includes a transfer assembly, whereby the transfer assembly includes a central gear and a stem. The central gear is configured to mesh with the distal gear of the engagement assembly. The stem extends distally from the central gear and defines a recess therein. 
     In yet a further embodiment, the drive assembly includes at least two engagement assemblies, whereby a distal gear of each engagement assembly enmeshed with the central gear of the transfer assembly. 
     Further still, in an embodiment, the drive assembly includes a coupler and a drive screw. The coupler defines a threaded aperture, whereby the coupler is rotationally affixed within the recess of the stem. The drive screw includes a threaded portion and a coupling feature. The threaded portion is configured to engage the threated aperture of the coupler, and the coupling feature configured to engage the coupling assembly. Rotation of the proximal gear of the engagement assembly drives rotation of the central gear of the transfer assembly and linear translation of the drive screw, with respect to the housing assembly. 
     In a further embodiment, the drive assembly includes a stop cap engaged with the housing assembly and disposed about the drive screw distal of the threaded portion thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein: 
         FIG. 1A  is a schematic illustration of a medical work station and operating console in accordance with the present disclosure; 
         FIG. 1B  is a perspective view of a motor of a control device of the medical work station of  FIG. 1A ; 
         FIG. 2  is a perspective view of an instrument drive assembly in accordance with an embodiment of the present disclosure; 
         FIG. 3  is rear perspective view of the instrument drive assembly of  FIG. 2 ; 
         FIG. 4  is a perspective, cross-sectional view of the instrument drive assembly of  FIG. 2  taken along the section line  4 - 4  of  FIG. 3 ; 
         FIG. 5A  is a rear perspective view of the instrument drive assembly of  FIG. 2  with various parts removed therefrom; 
         FIG. 5B  is a front perspective view of the instrument drive assembly of  FIG. 5A ; 
         FIG. 6  is a perspective view of an inner drive assembly and a drive member of the instrument drive assembly of  FIG. 2  coupled with an instrument drive shaft; 
         FIG. 7  is a perspective view of the area of detail of  FIG. 6 ; 
         FIG. 8A  is a side, cross-sectional view of the instrument drive assembly of  FIG. 2  taken along section line  8 - 8  of  FIG. 3  with a coupling assembly in a distal position; 
         FIG. 8B  is a side, cross-sectional view of the instrument drive assembly of  FIG. 2  taken along section line  8 - 8  of  FIG. 3  with the coupling assembly in a proximal position; 
         FIG. 9  is a side view of the area of detail of  FIG. 8A ; 
         FIG. 10  is a side, cross-sectional view of the instrument drive assembly of  FIG. 2  taken along section line  10 - 10  of  FIG. 2 ; 
         FIG. 11  is a perspective view of an instrument drive assembly in accordance with another embodiment of the present disclosure; 
         FIG. 12  is a front perspective view of the instrument drive assembly of  FIG. 11 ; 
         FIG. 13  is a rear perspective view of the instrument drive assembly of  FIG. 11 ; 
         FIG. 14  is a perspective, cross-sectional view of the instrument drive assembly of  FIG. 12  taken along the section line  14 - 14  of  FIG. 13 ; 
         FIG. 15  is a parts separated view of the instrument drive assembly of  FIG. 11 ; 
         FIG. 16  is a front perspective view of the instrument drive assembly of  FIG. 11  with various parts removed; 
         FIG. 17  is a side, cross-sectional view of the instrument drive assembly of  FIG. 12  taken along the section line  17 - 17  of  FIG. 13 ; 
         FIGS. 18A-18C  are side views of a retention mechanism of the instrument drive assembly of  FIG. 11  in various states of actuation during insertion of an instrument sleeve therein; 
         FIGS. 19A-19D  are side views of the retention mechanism of  FIGS. 18A-C  in various states of actuation during removal of the instrument sleeve therefrom; 
         FIGS. 20A-20C  are side views of a coupling assembly of the instrument drive assembly of  FIG. 11  in various states of actuation during coupling of an instrument drive shaft therewith; 
         FIG. 21A  is a perspective view of a drive assembly and a drive link of the instrument drive assembly of  FIG. 11  coupled with the instrument drive shaft; 
         FIG. 21B  is a perspective view of the area of detail of  FIG. 21A ; 
         FIG. 22  is a rear perspective view of an instrument drive assembly in accordance with another embodiment of the present disclosure; 
         FIG. 23  is a perspective, cross-sectional view of the instrument drive assembly of  FIG. 22  taken along the section line  23 - 23  of  FIG. 22 ; 
         FIG. 24  is a perspective view, with parts separated, of the instrument drive assembly of  FIG. 22 ; 
         FIG. 25  is a front perspective view of the instrument drive assembly of  FIG. 22  with various parts removed; 
         FIG. 26  is a side, cross-sectional view of the instrument drive assembly of  FIG. 22  taken along the section line  26 - 26  of  FIG. 22 ; 
         FIGS. 27A and 27B  are top views of a button and a latch plate of a retention mechanism of the instrument drive assembly of  FIG. 22  in a first position and a second position, respectively; 
         FIGS. 28A-28D  are side perspective views and cross-sections of the retention mechanism of the instrument drive assembly of  FIG. 22  in various states of actuation; 
         FIGS. 29A and 29B  are perspective views, and  FIG. 29C  is a top view, of the retention mechanism of  FIGS. 28A-28D  in various states of actuation during insertion of an instrument sleeve therein; 
         FIGS. 30A-30C  are side, cross-sectional views of a coupling assembly of the instrument drive assembly of  FIG. 22  in various states of actuation during coupling of an instrument drive shaft therewith; 
         FIG. 31A  is a perspective view of a drive assembly and a drive link of the instrument drive assembly of  FIG. 22  coupled with the instrument drive shaft; 
         FIG. 31B  is a perspective view of the area of detail of  FIG. 31A ; 
         FIG. 32  is a perspective view of another embodiment of an instrument drive assembly coupled with another embodiment of a surgical instrument; 
         FIG. 33  is an enlarged, cross-sectional view of the surgical instrument of  FIG. 32  as taken along section line  33 - 33  of  FIG. 32 ; and 
         FIG. 34  is an end view of  FIG. 33 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the presently disclosed instrument drive assemblies are 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 used in the art, the term “distal” refers to a position of an instrument, or portion thereof, which is farther from the user, and the term “proximal” refers to a position of an instrument, or portion thereof, which is closer to the user. In addition, all spatial references, such as, for example, horizontal, vertical, top, upper, lower, bottom, left and right, are for illustrative purposes only and can be varied within the scope of the disclosure. For example, the references “upper” and “lower” are relative and used only in the context to the other, and are not necessarily “superior” and “inferior” or vice versa. 
     Referring initially to  FIGS. 1A and 1B , a medical work station is shown generally as work station  1  and generally includes a plurality of robot arms  2 ,  3 ; a control device  4 ; and an operating console  5  coupled with control device  4 . Operating console  5  includes a display device  6 , which is set up in particular to display three-dimensional images; and manual input devices  7 ,  8 , by means of which a person (not shown), for example a surgeon, is able to telemanipulate robot arms  2 ,  3  in a first operating mode, as known in principle to a person skilled in the art. 
     Each of the robot arms  2 ,  3  includes a plurality of members, which are connected through joints, and an instrument control unit  100 , to which may be attached, for example, to an instrument drive assembly  200  of a surgical instrument  1000 , the surgical instrument  1000  supporting an end effector (not shown) including, for example, a pair of jaw members, electrosurgical forceps, cutting instruments, or any other endoscopic, or open, surgical devices. For a detailed discussion and illustrative examples of the construction and operation of an end effector for use with instrument control unit  100 , reference may be made to commonly owned International patent Application No. PCT/US14/61329, filed on Oct. 20, 2014 (International Patent Publication No. WO 2015/088647, and entitled “Wrist and Jaw Assemblies for Robotic Surgical Systems,” now U.S. Patent Publication No. US 2016/0303743, the entire content of which is incorporated herein by reference. 
     Robot arms  2 ,  3  may be driven by electric drives (not shown) that are connected to control device  4 . Control device  4  (e.g., a computer) is set up to activate the drives, in particular by means of a computer program, in such a way that robot arms  2 ,  3 , instrument control units  100 , and thus the surgical instruments  10  execute a desired movement or articulation according to a movement defined by means of manual input devices  7 ,  8 . Control device  4  may also be set up in such a way that it regulates the movement of robot arms  2 ,  3  and/or of the drives. 
     Medical work station  1  is configured for use on a patient  13  lying on a patient table  12  to be treated in an open surgery, or a minimally invasive manner, by means of surgical instrument  1000 . Medical work station  1  may also include more than two robot arms  2 ,  3 , the additional robot arms likewise being connected to control device  4  and being telemanipulatable by means of operating console  5 . An instrument control unit and a surgical instrument may also be attached to the additional robot arm. Medical work station  1  may include a database  14 , in particular coupled to or with control device  4 , in which pre-operative data from patient  13  and/or anatomical atlases, for example, may be stored. 
     For a detailed discussion of the construction and operation of medical work station  1  reference may be made to U.S. Pat. No. 8,828,023, filed on Nov. 3, 2011 and entitled “Medical Workstation,” the entire content of which is incorporated herein by reference. 
     Control device  4  may control a plurality of motors (e.g., “M 1 ”-“M 6 ”). Motors “M” may be part of instrument control unit  100  and/or disposed externally of instrument control unit  100 . Motors “M” (e.g., motors “M” being located externally of instrument control unit  100 ) may be configured to rotate a crown gear “CG” ( FIG. 1B ), or the like, that is keyed to or non-rotatably supported on a rotatable shaft of at least some of motors “M,” or act on a cable to draw in or let out length of cable to actuate robot arms  2 ,  3 . In use, as motors “M” are driven, the rotation of crown gear(s) “CG” effects operation, movement, and/or articulation of instrument drive assembly  200  of surgical instrument  1000 , and an end effector attached thereto, as discussed below. It is further envisioned that at least one motor “M” receives signals wirelessly (e.g., from control device  4 ). It is contemplated that control device  4  coordinates the activation of the various motors (Motor  1  . . . n) to coordinate an operation, movement, and/or articulation of robot arms  2 ,  3  and/or surgical instrument  1000 . It is envisioned that each motor may corresponds to a separate degree of freedom of robot arms  2 ,  3 , and/or surgical instrument  1000  engaged with instrument control unit  100 . It is further envisioned that more than one motor, including every motor (Motor  1  . . . n), is used for each degree of freedom. 
     Turning now to  FIGS. 2-13 , instrument drive assembly  200  is configured to engage instrument control unit  100  at a proximal end  201  thereof and couple to surgical instrument  1000  at a distal end  202  thereof, where surgical instrument  1000  extends distally from instrument drive assembly  200 , as described herein. Instrument drive assembly  200  is configured to transfer rotational movement supplied by instrument control unit  100  (e.g., via motors “M”) into longitudinal movement of a drive member  380  ( FIGS. 5A and 7-10 ) to effect various functions of surgical instrument  1000 . 
     With reference to  FIGS. 2 and 8-10 , instrument drive assembly  200  includes a housing assembly  205  which includes a proximal housing  210  and a distal housing  220 . Proximal housing  210  and distal housing  220  are releasably couplable to each other, which may facilitate assembly of instrument drive assembly  200 , and which may facilitate access, repair, and/or replacement of parts housed at least partially therein. Housing assembly  205  defines at least one bore  207  (as best illustrated in  FIG. 4 ) for housing an inner drive assembly  300  ( FIG. 7 ) therein. It is envisioned that housing assembly  205  includes four separate bores  207 , where each bore  207  is at least partially separated from each other and where each bore  207  is configured to house a separate single inner drive assembly  300 . Additionally, as discussed below, each respective bore  207  includes a longitudinally-extending channel  206  (e.g., four channels  206 ) therein ( FIG. 4 ). Each channel  206  is configured to slidingly accept a rail  353  of a drive nut  350  ( FIG. 7 ), as described below. In the illustrated embodiment, instrument drive assembly  200  includes four inner drive assemblies  300 , however instrument drive assembly  200  may include more (e.g., five or six) or fewer (e.g., three) inner drive assemblies  300  without departing from the scope of the present disclosure. It is further envisioned that all inner drive assemblies  300 , or a select number of inner drive assemblies, may be coupled to one or more respective drive members  380 , whereas the exemplary illustration provides a singular inner drive assembly  300  coupled to drive member  380 , as described below. 
     With reference to  FIGS. 3, 4 and 7 , each inner drive assembly  300  includes a proximal gear  310 , a proximal bearing  320 , a distal bearing  330 , a drive screw  340 , and drive nut  350 . Drive screw  340  includes a proximal portion  342 , a proximal shaft  343 , a threaded portion  345  and a distal shaft  344 , and defines a longitudinal axis “A-A” extending through a radial center thereof ( FIG. 7 ). Proximal gear  310  is configured to engage, directly or indirectly, with an instrument control gear (e.g., crown gear “CG” of motor “M”) of instrument control unit  100 , such that rotation of crown gear “CG” causes a corresponding rotation of proximal gear  310 . Proximal gear  310  may be a crown gear “CG” that is configured to mate with and/or mesh with crown gear “CG” of motor “M.” Proximal gear  310  includes an aperture  312  extending longitudinally therethrough configured to mechanically engage proximal portion  342  of drive screw  340 . As shown, aperture  312  and proximal portion  342  of drive screw  340  have corresponding, non-circular cross-sections, such that proximal gear  310  and drive screw  340  are keyed to one another, which results in a rotationally fixed connection therebetween. Rotation of proximal gear  310  causes drive screw  340  to rotate about longitudinal axis “A” in a corresponding direction and rate of rotation. 
     Drive nut  350  includes a threaded aperture  352  extending longitudinally therethrough, which is configured to mechanically engage threaded portion  345  of drive screw  340 . That is, drive nut  350  and drive screw  340  are threadingly engaged with each other. Drive nut  350  includes rail  353  extending longitudinally along an outer surface thereof and is configured to be slidably disposed in the longitudinally extending channel  206  formed in bore  207  of housing assembly  205  ( FIGS. 6 and 9 ). Rail  353  of drive nut  350  cooperates with channel  206  of bore  207  to inhibit or prevent drive nut  350  from rotating about longitudinal axis “A” as drive screw  340  is rotated. Accordingly, drive nut  350  is configured to be positioned on drive screw  340  in a manner such that rotation of drive screw  340  causes longitudinal translation of drive nut  350 . More specifically, rotation of proximal gear  310  in a first direction (e.g., clockwise) causes drive screw  340  to rotate in a corresponding first direction and drive nut  350  to translate in a first longitudinal direction (e.g., proximally) with respect to proximal gear  310 , and rotation of proximal gear  310  in a second direction (e.g., counter-clockwise) causes drive screw  340  to rotate in a corresponding second direction and drive nut  350  to translate in a second longitudinal direction (e.g., distally) with respect to proximal gear  310 . 
     Drive nut  350  further defines a bore-hole  354  laterally offset from, and parallel to, threaded aperture  352 . It is contemplated that bore-hole  354  may define threads on an inner surface such that drive nut  350  may be coupled to drive member  380 , as discussed below. 
     As illustrated ( FIGS. 5A and 9 ), the drive nut  350  of one inner drive assembly  300  is coupled to drive member  380 , where drive member  380  may define, for example, a drive bar or push bar, as described below. A link bar  360  defining two bore-holes  362 ,  364  laterally offset from one another is configured to couple drive nut  350  and drive member  380  ( FIGS. 7 and 9 ). It is contemplated that a respective link bar  360  may be provided for each respective inner drive assembly  300 , or a select number of link bars  360  may be provided for a select number of inner drive assemblies  300 , such that each drive nut  350  of the respective inner drive assembly  300  may be coupled to either a respective drive member  380 , or the same drive member  380 . 
     Link bar  360  may be monolithically formed with drive nut  350 , drive member  380 , or both drive nut  350  and drive member  380 , such that drive nut  350 , link bar  360 , and drive member  380  consist of one unitary body. Alternatively, drive nut  350 , link bar  360 , and drive member  380  may be fastened by any mechanical means known in the art, such as, for example, by utilizing a screw or bolt. In such an embodiment, bore-holes  362 ,  364  of link bar  360  may define threads on an inner surface thereof, such that a bolt or screw may be threadably engaged between link bar  360  and drive nut  350 , and link bar  360  and drive member  380 . More specifically, a screw may be threadably engaged through bore-hole  362  of link bar  360  and bore-hole  354  of drive nut  350 , thereby securing link bar  360  thereto. An additional screw may be threadably engaged through bore-hole  364  of link bar  360  and a bore-hole  382  of drive member  380 , thereby securing link bar  360  thereto. With drive nut  350  coupled to drive member  380 , it should be appreciated that proximal and distal translation of drive nut  350  with respect to proximal gear  310  results in a corresponding proximal or distal translation of drive member  380 , as discussed in further detail below. 
     With inner drive assembly  300  and housing assembly  205  assembled, proximal bearing  320  is disposed in a proximal bearing cavity  211  of proximal housing  210 , and distal bearing  330  is disposed in a distal bearing cavity  212  of distal housing  220  ( FIG. 9 ). Each of proximal bearing  320  and distal bearing  330  facilitate rotation of drive screw  340  with respect to housing assembly  205 , and may further serve as proximal and distal stops, respectively, for drive nut  350 . 
     Drive member  380  extends distally from link bar  360 , through a central bore  208  ( FIGS. 8-10 ) of housing assembly  205 , and is configured to mechanically engage a portion of surgical instrument  1000 , as described herein. Longitudinal translation of drive member  380  is configured to drive a function of the end effector disposed at a distal end of surgical instrument  1000 . For example, surgical instrument  1000  may include a first end effector configured such that distal translation of drive member  380  directs a pair of jaw members of a clamping device to move into approximation with respect to one another, and proximal translation of drive member  380  may be configured to move at least one jaw member into a spaced apart position with respect to the other jaw member. It should be appreciated that proximal and distal translation of drive member  380  may be configured to effect operation, articulation, or actuation of any number of unique end effectors of a respective surgical instruments  1000 , such as, for example, actuation of a cutting blade and/or initiation of the delivery of electrosurgical energy to tissue, etc. 
     With reference to  FIGS. 2, 8A and 8B , the engagement of surgical instrument  1000  to instrument drive assembly  200 , and more particularly to housing assembly  205  and drive member  380 , will be described. Housing assembly  205  further includes a coupling assembly  500  disposed distally of distal end  202  of housing assembly  205 . Coupling assembly  500  serves to releasably couple surgical instrument  1000  to housing assembly  205 , and releasably couple an instrument drive shaft  1020  of surgical instrument  1000  to drive member  380  ( FIGS. 8A-10 ). 
     Briefly, surgical instrument  1000  may include an instrument sleeve  1010 , which defines a longitudinally extending lumen  1012  configured to receive at least a portion of instrument drive shaft  1020  therein, and an end effector (not shown) coupled to, and disposed at, a distal end of instrument drive shaft  1020 . Instrument drive shaft  1020  is configured to translate longitudinally within the lumen  1012  of instrument sleeve  1010 , such that instrument drive shaft  1020  controls actuation, articulation, and/or firing of the end effector, such as, for example, approximation of first and second jaw members to grasp tissue therebetween, advancement of a knife blade to sever tissue, articulation of the orientation and/or direction of the end effect, and/or any other function described herein or known in the art. More specifically, through proximal and distal translation of instrument drive shaft  1020 , with respect to instrument sleeve  1010 , instrument drive shaft  1020  actuates the end effector. For example, translation of instrument drive shaft  1020  in a first direction (e.g., distally), may cause a first and second jaw member (not shown) to move into a spaced apart configuration with respect to one another such that tissue may be disposed therebetween, and translation of instrument drive shaft  1020  in a second direction (e.g., proximally) may cause the first and second jaw members to move into an approximated configuration with respect to one another such that tissue disposed therebetween is securely grasped. It should be appreciated that the above examples are exemplary in nature, and the instrument drive shaft  1020  and end effector may be configured to actuate in any number of ways. 
     With reference to  FIGS. 8A-10 , a coupling tube  400  serves to interconnect housing assembly  205  and coupling assembly  500 . Coupling tube  400  includes a proximal portion  402  disposed in a distal cavity  250  of distal housing  220  of housing assembly  205 , and extends distally therefrom. Distal cavity  250  is coaxial with central bore  208  of housing assembly  205  and is configured to receive a diameter of coupling tube  400  therein. As illustrated, a longitudinally extending lumen  410  of coupling tube  400  is configured to slidingly receive a distal portion  390  of drive member  380  therein, such that a portion of drive member  380  is translatable therethrough. Coupling tube  400  extends distally through a longitudinal cavity  510  of coupling assembly  500 , such that coupling assembly  500  is slidably supported thereon, as discussed below. As such, it should be appreciated that central bore  208  of housing assembly  205 , drive member  380 , coupling tube  400 , and longitudinal cavity  510  of coupling assembly  500  are coaxial. 
     Coupling assembly  500  is longitudinally translatable along coupling tube  400  between a proximal position ( FIG. 8B ) and a distal position ( FIG. 8A ), with respect to housing assembly  205 . As will be described below, in the proximal position, instrument sleeve  1010  of surgical instrument  1000  is releasably coupled to coupling assembly  500  and instrument drive shaft  1020  is releasably coupled to drive member  380 ; and in the distal position, instrument sleeve  1010  is securely coupled to coupling assembly  500  and instrument drive shaft  1020  is securely coupled to drive member  380 . It is envisioned that coupling assembly  500  may additionally aid alignment of instrument drive shaft  1020  and drive member  380  during coupling. 
     More specifically, instrument sleeve  1010  of surgical instrument  1000  is slidably inserted into a distal opening  404  of coupling tube  400 . A notch  1014  extending outward from an outer surface of instrument sleeve  1010  is configured to abut distal end  404  of coupling tube  400  when instrument sleeve  1010  of surgical instrument  1000  is fully inserted therein. It is further envisioned that coupling assembly  500  provides a retention mechanism  550 , such that instrument sleeve  1010  of surgical instrument  1000  is releasably retained or secured within coupling tube  400 , and thus, releasably secured to coupling assembly  500  and thus housing assembly  205 . As will be described herein below, retention mechanism  550  is transitionable between a locked configuration and an unlocked configuration. 
     It is contemplated that as instrument sleeve  1010  of surgical instrument  1000  slides proximally within coupling tube  400 , a button or biasing member  552  disposed in longitudinal cavity  510  of coupling assembly  500  is configured to engage a recess  1015  disposed on the outer surface of instrument sleeve  1010 . As best illustrated in  FIGS. 8A and 8B , button  552  may be disposed in longitudinal cavity  510  such that it resides in a radial cavity  405  extending through a portion of coupling tube  400 . It should be appreciated that button  552  translates radially inward with respect to a longitudinal axis “B” ( FIG. 8A ) of coupling tube  400  to engage instrument sleeve  1010  of surgical instrument  1000  in the locked configuration, and translates radially outward ( FIG. 8B ) to disengage instrument sleeve  1010  in the unlocked configuration. With button  552  in the locked configuration, button  552  is engaged with recess  1015  such that longitudinal translation of instrument sleeve  1010  of surgical instrument  1000 , within coupling tube  400 , is inhibited, and in the unlocked configuration, button  552  is disengaged from recess  1015  such that instrument sleeve  1010  freely slides proximally and distally within coupling tube  400 . Radial cavity  405  may be transverse to the longitudinal axis “B” of coupling tube  400 , such that when button  552  actuates between the locked and unlocked configurations, button  552  translates perpendicular to coupling tube  400 , and instrument sleeve  1010  of surgical instrument  1000  inserted therein. Alternatively, radial cavity  405  and button  552  may be configured such that button  552  translates at an angle with respect to the longitudinal axis “B” of coupling tube  400 , such that button  552  slides into and out of engagement with recess  1015  of instrument sleeve  1010  of surgical instrument  1000 . 
     It is further contemplated that retention mechanism  550  may be disposed proximally of distal end  404  of coupling tube  400 , such that instrument sleeve  1010  of surgical instrument  1000  slides within coupling tube  400  in a proximal direction an initial distance prior to engaging button  552  of retention member  550 . It is further envisioned that a biasing member  555  may be disposed within longitudinal cavity  510  of coupling assembly  500  which is configured to bias button  552  into the locked configuration. Biasing member  555  may include a spring element disposed within radial cavity  405  in abutment with both button  552  and longitudinal cavity  510  and/or coupling tube  400 . With button  552  biased into the locked configuration, as instrument sleeve  1010  slides proximally, the bias member  555  is overcome and button  552  is urged radially outward into the unlocked configuration. Once instrument sleeve  1010  is translated proximally the initial distance, recess  1015  is aligned with button  552 , permitting button  552  to return to the locked configuration. 
     As referenced above, coupling assembly  500  of housing assembly  205  is slidably supported on coupling tube  400  between a proximal position and a distal position with respect to housing assembly  205 . With coupling assembly  500  in the distal position, e.g., a locked configuration, button  552  of retention mechanism  550  is maintained in the locked configuration with respect to instrument sleeve  1010  of surgical instrument  1000 , and with coupling assembly  500  in the proximal position, e.g., an unlocked configuration, button  552  may be actuated into the unlocked configuration with respect to instrument sleeve  1010 . Thus, translation of coupling assembly  500  permits the locking and unlocking of instrument sleeve  1010  of surgical instrument  1000 . 
     It should be appreciated that a distal portion  511  of longitudinal cavity  510  of coupling assembly  500  defines a larger diameter, such that when coupling assembly  500  is in the proximal position, distal portion  511  of the longitudinal cavity  510  aligns with button  552 , such that button  552  is disposed therein and thus permitted to translate radially outward into the unlocked configuration with respect to instrument sleeve  1010  of surgical instrument  1000 . 
     It is contemplated that coupling assembly  500  further includes a biasing element  580 , such that coupling assembly  500  is biased into the distal position, e.g., the locked configuration. In an exemplary illustration, biasing element  580  is disposed in a proximal portion  509  of longitudinal cavity  510 , however it is envisioned that biasing element  580  may be disposed in any portion of coupling assembly  500 . More specifically, when uncoupling surgical instrument  1000  from instrument drive assembly  200 , coupling assembly  500  is translated proximally, such that button  552  aligns with the distal portion  511  of the longitudinal cavity  510  of coupling assembly  500 , and such that button  552  may translate radially outward, out of engagement with recess  1015  of instrument sleeve  1010 . With button  552  disengaged, instrument sleeve  1010  is permitted to slide distally to be removed from coupling tube  400 , and instrument drive assembly  200 . 
     With reference to  FIGS. 7-9 , engagement of drive member  380  of inner drive assembly  300  and instrument drive shaft  1020  of surgical instrument  1000  will be discussed. As best illustrated in  FIG. 7 , a distal portion  382  of drive member  380  defines an engagement region  386 . Engagement region  386  of drive member  380  includes a plurality of longitudinally extending slits  384 , where each slit  384  is disposed about a circumference of a distal end  388  of drive member  380 , and extends proximally therefrom along a portion of drive member  380 . As a result of the plurality of longitudinally extending slits  384 , the engagement region  386  of drive member  380  forms an expandable leaf feature, and may thus flex radially outward to facilitate the releasable coupling of instrument drive shaft  1020  of surgical instrument  1000  therewith. It is further envisioned that an inner surface of retention region  386  of drive member  380  may define an arcuate cavity, e.g., a socket joint, configured to receive a coupling ball  1022  of instrument drive shaft  1020  of surgical instrument  1000 , as described below. It is contemplated that engagement region  386  of drive member  380  further includes retention hooks  385  disposed at the distal end  388  of drive member  380  on an inner facing surface thereof, where retention hooks  385  facilitate retention of coupling ball  1022  of instrument drive shaft  1020  therein. 
     More specifically, instrument drive shaft  1020  of surgical instrument  1000  includes a neck  1024  extending proximally from a proximal end  1021  thereof, where coupling ball  1022  (shown in phantom in  FIG. 7 ) is disposed at a proximal end  1023  of neck  1024 . It is contemplated that coupling ball  1022 , neck  1024 , and instrument drive shaft  1020  may be coupled by any means known in the art and/or may be monolithically formed. A diameter of neck  1024  may be smaller than a diameter of coupling ball  1022 , such that when coupling ball  1022  is received within retention region  386  of drive member  380 , retention hooks  385  of retention region  386  surround and enclose coupling ball  1022 , thus providing further securement therein. When coupling drive member  380  of inner drive assembly  300  and instrument drive shaft  1020  of surgical instrument  1000 , the coupling ball  1022  of instrument drive shaft  1020  is brought into approximation with retention region  386  of drive member  380 . As instrument drive shaft  1020  is moved proximally with respect to drive member  380 , coupling ball  1022  urges retention region  386  to flex radially outward, such that coupling ball  1022  is received therein. With coupling ball  1022  received within retention region  386 , coupling ball  1022  is thereby releasably coupled to drive member  380 . With drive member  380  coupled to instrument drive shaft  1020 , proximal and distal translation of drive member  380  directs a corresponding proximal and distal translation of instrument drive bar  1020 . 
     To uncouple instrument drive shaft  1020  of surgical instrument  1000  from drive member  380  of inner drive assembly  300 , instrument drive bar  1020  is moved distally with respect to drive member  380 , such that coupling ball  1022  is pulled out of, and released from, retention region  386 . 
     During use, with instrument drive assembly  200  in an active state (e.g., when motor(s) “M” of instrument control unit  100  rotate proximal gear(s)  310 ), rotation of proximal gear  310  results in a corresponding rotation of drive screw  340 . Rotation of drive screw  340  causes longitudinal translation of drive nut  350  due to the engagement between threaded portion  345  of drive screw  340  and threaded aperture  352  of drive nut  350 . As discussed above, the direction of rotation of proximal gear  310 , and thus drive screw  340 , determines the direction of longitudinal translation of drive nut  350 . With instrument sleeve  1010  of surgical instrument  1000  coupled to coupling assembly  500 , and instrument drive shaft  1020  coupled to drive member  380 , rotation of proximal gear  310  directs linear translation of drive member  380  and instrument drive shaft  1020 . More specifically, rotation of proximal gear  310  in a first direction (e.g., clockwise) causes drive screw  340  to rotate in a corresponding first direction and drive nut  350  to translate in a first longitudinal direction (e.g., proximally) with respect to proximal gear  310 , which translates drive member  380  and instrument drive shaft  1020  in a corresponding first longitudinal direction (e.g., proximally). Rotation of proximal gear  310  in a second direction (e.g., counter-clockwise) causes drive screw  340  to rotate in a corresponding second direction and drive nut  350  to translate in a second longitudinal direction (e.g., distally) with respect to proximal gear  310 , which translates drive member  380  and instrument drive shaft  1020  in a corresponding second longitudinal direction (e.g., distally). 
     With reference to  FIGS. 11-21B , an alternate embodiment of instrument drive assembly  200 , in accordance with the present disclosure, will be described with reference to instrument drive assembly  2000 . As discussed below, instrument sleeve  1010  and instrument drive shaft  1020  of surgical instrument  1000  are also releasably couplable to instrument drive assembly  2000 . 
     With reference to  FIGS. 11, 12 and 15 , instrument drive assembly  2000  includes a housing assembly  2005  having a first side  2001  and a second side  2002 , where first and second sides  2001 ,  2002  define a cavity  2020  therebetween. Housing assembly  2005  further includes a proximal end plate  2010  supported at a proximal end  2003  thereof, a distal end plate  2030  supported at a distal end  2004  thereof, a drive assembly  2300  supported in cavity  2020 , an internal plate  2040  supported in cavity  2020 , a coupling assembly  2500  disposed in cavity  2020 , and a coupling tube  2400  supported by distal end plate  2030  and extending distally thereof. As best illustrated in  FIG. 15 , first and second sides  2001 ,  2002  of housing assembly  2005  act as two halves of a shell, with proximal end plate  2010  acting as a proximal wall and distal end plate  2030  acting as a distal wall. Housing assembly  2005  further includes a release mechanism  2006  disposed on first side  2001 , second side  2002 , and/or both first and second sides  2001 ,  2002 . Release mechanism  2006  of housing assembly  2005  serves to provide a quick and easy means for coupling and uncoupling instrument drive assembly  2000  and instrument control unit  1000 . 
     Proximal end plate  2010  of housing assembly  2005  defines at least one through-hole  2011  therein, and in an embodiment it is envisioned that proximal end plate  2010  may define four through-holes  2011  therein. Each through-hole  2011  is configured to receive a proximal gear  2310  of drive assembly  2300  therethrough, such that proximal gear  2310  may engage the instrument control gear of instrument control unit  100 . 
     Distal end plate  2030  of housing assembly  2005  includes at least one rod receiving portion  2032  and at least one distal bearing cavity  2039 , where the rod receiving portion  2032  and the distal bearing cavity  2039  are disposed on a proximal surface  2036  thereof. In an embodiment it is envisioned that distal end plate  2030  may include a pair of rod receiving portions  2032  laterally offset from each other. Distal end plate  2030  further defines an elongated cavity  2034 , such that elongated cavity  2034  extends inward from an outer edge  2038  of distal end plate  2030  to align with a longitudinal axis “C” of housing assembly  2005  ( FIGS. 11 and 17 ). It is envisioned that elongated cavity  2034  of distal end plate  2030  of housing assembly  2005  defines a generally “U” shaped cavity configured to support coupling tube  2400 , such that coupling tube  2400  is supported therein and extends distally from cavity  2020  of housing assembly  2005 , as described below. 
     Internal plate  2040  of housing assembly  2005  defines a first through-hole  2042  which is coaxial with the longitudinal axis “C” of housing assembly  2005 , a second through-hole  2044  laterally offset from longitudinal axis “C” and which is coaxial with at least one through-hole  2011  of proximal end plate  2010 , and at least one rod receiving portion  2046  laterally offset from longitudinal axis “C”. A side edge  2048  of internal plate  2040  is supported in a channel  2021  defined in an inner surface  2022  of both first and second sides  2001 ,  2002  of housing assembly  2005 , such that internal plate  2040  is fixed therein. It is envisioned that internal plate  2040  provides structural support for housing assembly  2005 , and further provides support for drive assembly  2300 , as discussed below. 
     With reference to  FIGS. 15-17 , drive assembly  2300  of housing assembly  2005  will be further described. Drive assembly  2300  of housing assembly  2005  includes a proximal gear  2310 , a proximal bearing  2320 , a distal bearing  2330 , a drive screw  2340 , a drive plate  2350 , and a guide rod  2360 . Drive screw  2340  includes a proximal portion  2342 , a proximal shaft  2343 , a threaded portion  2345  and a distal shaft  2344 , and defines a longitudinal axis “D” extending through a radial center thereof ( FIG. 16 ). Proximal gear  2310  is configured to engage with the instrument control gear (e.g., crown gear “CG” of motor “M”) of instrument control unit  100 , such that rotation of crown gear “CG” causes a corresponding rotation of proximal gear  2310 . Proximal gear  2310  may be a crown gear “CG” that is configured to mate with and/or mesh with crown gear “CG” of motor “M.” Proximal gear  2310  includes an aperture  2312  extending longitudinally therethrough configured to mechanically engage proximal portion  2342  of drive screw  2340 . As illustrated, aperture  2312  and proximal portion  2342  of drive screw  2340  have corresponding, non-circular cross-sections, such that proximal gear  2310  and drive screw  2340  are keyed to one another, which results in a rotationally fixed connection therebetween. Rotation of proximal gear  2310  causes drive screw  2340  to rotate about longitudinal axis “D” of drive screw  2340  in a corresponding direction and rate of rotation. 
     Drive plate  2350  of drive assembly  2300  includes at least one threaded aperture  2352  and at least one through-hole  2354  extending longitudinally therethrough. Threaded aperture  2352  is configured to mechanically engage threaded portion  2345  of drive screw  2340 . That is, drive plate  2350  and drive screw  2340  of drive assembly  2300  are threadingly engaged with each other. Guide rod  2360  of drive assembly  2300  is slidably disposed in a through-hole  2354  of drive plate  2350 , where a first end  2362  of guide rod  2360  is coupled to rod receiving portion  2032  of distal end plate  2030  and a second end  2364  of guide rod  2360  is coupled to rod receiving portion  2046  of internal plate  2040 . It is envisioned that guide rod  2360  is laterally offset from, and parallel to, longitudinal axis “D” of drive screw  2340 . It should be appreciated that housing assembly  2005  may include any number of guide rods  2360 , where each guide rod  2360  is disposed in a respective rod receiving portion  2032  of proximal end plate  2030 , a respective rod receiving portion  2046  of internal plate  2040 , and a respective through-hole  2353  of drive plate  2350 . In an embodiment, it is envisioned that housing assembly  2005  may include a pair of guide rods  2360 , where guide rods  2360  are laterally offset from, and symmetrically spaced about, longitudinal axis “C” of housing assembly  2005 . As such, guide rod  2360  inhibits or prevents drive plate  2350  from rotating about longitudinal axis “D” of drive screw  2340  as drive screw  2340  is rotated. Accordingly, drive plate  2350  is configured to be engaged with drive screw  2340  in a manner such that rotation of drive screw  2340  causes longitudinal translation of drive plate  2350 . More specifically, rotation of proximal gear  2310  in a first direction (e.g., clockwise) causes drive screw  2340  to rotate in a corresponding first direction and drive plate  2350  to translate in a first longitudinal direction (e.g., proximally) with respect to proximal gear  2310 , and rotation of proximal gear  2310  in a second direction (e.g., counter-clockwise) causes drive screw  2340  to rotate in a corresponding second direction and drive plate  2350  to translate in a second longitudinal direction (e.g., distally) with respect to proximal gear  2310 . 
     Drive plate  2350  of drive assembly  2300  further includes a mounting bracket  2370  extending distally from a distal facing surface  2371  thereof. With brief reference to  FIG. 15 , mounting bracket  2370  of drive plate  2350  supports coupling assembly  2500  thereon. Coupling assembly  2500  is configured to mechanically engage instrument drive shaft  1020  of surgical instrument  1000 , such that proximal and distal translation of drive plate  2350 , with respect to proximal gear  2310 , results in proximal and distal translation of instrument drive shaft  1020 , as discussed in further detail below. Longitudinal translation of drive plate  2350  is configured to drive a function of the end effector of surgical instrument  1000  in a similar fashion as drive member  380  of instrument drive assembly  200 , and thus will not be discussed in any further detail herein. Longitudinal translation of drive plate  2350  further directs locking and unlocking of coupling assembly  2500  with respect to instrument drive shaft  1020 , as discussed below. 
     With drive assembly  2300  and housing assembly  2005  assembled, proximal bearing  2320  of drive assembly  2300  is supported in through-hole  2011  of internal plate  2040 , and distal bearing  2330  of drive assembly  2300  is disposed in distal bearing cavity  2039  of distal end plate  2030  ( FIG. 17 ). Each of proximal bearing  2320  and distal bearing  2330  facilitate rotation of drive screw  2340  with respect to housing assembly  2005 , where internal plate  2040  and distal end plate  2030  may serve as proximal and distal stops, respectively, for drive plate  2350 . Drive assembly  2300  may further include a washer or spacer  2301  disposed about proximal shaft  2343  of drive screw  2030 , between proximal bearing  2320  of drive assembly  2300  and threaded portion  2345  of drive screw  2340  of drive assembly  2300 . Washer  2301  further facilitates rotation of drive screw  2340 . Drive assembly  2300  may further include a biasing element  2380  disposed about drive screw  2340  between washer  2301  and drive plate  2350 . Biasing element  2380  serves as a return spring providing distal bias to drive plate  2340 , as discussed below. 
     Referring to  FIG. 17 , housing assembly  2005  further includes coupling tube  2400 . Coupling tube  2400  includes a proximal end  2402  defining a through-hole  2403 , and a longitudinal bore or lumen  2405  extending distally therefrom. It is envisioned that longitudinal bore  2405  defines a larger diameter than through-hole  2403 , such that longitudinal bore  2405  is configured to receive both instrument sleeve  1010  and instrument drive shaft  1020  of surgical instrument  1000  therein, and through-hole  2403  is configured to receive only instrument drive shaft  1020  therethrough, as discussed below. Coupling tube  2400  is supported in elongated cavity  2034  of distal end plate  2030  of housing assembly  2005  such that a distal portion  2401  of couple tube  2400  extends distally therefrom. It is envisioned that coupling tube  2400  may be monolithically formed with distal end plate  2030 , or may alternatively be releasably couplable to elongated cavity  2034 , such that coupling tube  2400  slides into and out of engagement with elongated cavity  2030 . Longitudinal bore  2405  and through-hole  2403  of coupling tube  2400  define a longitudinal axis “T” of coupling tube  2400  ( FIG. 18A ), which may be coaxial with longitudinal axis “C” of housing assembly  2005 . Longitudinal bore  2405  is configured to slidingly receive a proximal portion  1009  of instrument sleeve  1010 . It is envisioned that during coupling of surgical instrument  1000  with instrument drive assembly  2000 , coupling tube  2400  may aid alignment of instrument drive shaft  1020  and drive assembly  2300 . More specifically, instrument sleeve  1010  of surgical instrument  1000  is slidably inserted into a distal opening  2404  of coupling tube  2400  of housing assembly  2005  of instrument drive assembly  2000 . When instrument sleeve  1010  of surgical instrument  1000  is fully inserted into longitudinal bore  2405  of coupling tube  2400 , a proximal end  1011  of instrument sleeve  1010  abuts a distally facing surface of proximal end  2402  of coupling tube  2400 . 
     Housing assembly  2005  further includes a retention mechanism  2550  configured to releasably retain or secure instrument sleeve  1010  of surgical instrument  1000  to coupling tube  2400 , and thus to housing assembly  2005 . With reference to  FIGS. 15, 16, and 18A-19D , retention mechanism  2550  includes a lock plate  2552 , a button  2555 , and a release arm  2558 . Coupling tube  2400  of housing assembly  2005  defines a locking cavity  2551  disposed along a length thereof, such that lock plate  2552  is slidably insertable therein. Lock plate  2552  defines a through-hole  2553  configured to slidingly receive instrument sleeve  1010  therethrough, and is transitionable between a locked and unlocked configuration, with respect to instrument sleeve  1010 , as discussed below. More specifically, in the locked configuration through-hole  2553  of lock plate  2552  is off-axis of, and offset or angled from, the longitudinal axis “T” of coupling tube  2400 , and in the unlocked configuration through-hole  2553  of lock plate  2552  is coaxial with the longitudinal axis “T” of coupling tube  2400 . 
     Release arm  2558  of retention mechanism  2550  defines an engagement region  2557  configured to engage a portion of button  2555 , and an abutment region  2556 , configured to abut lock plate  2552 . Button  2555  is slidably coupled to housing assembly  2005 , and actuatable between first and second positions. As button  2555  translates proximally, with respect to housing assembly  2005 , button  2555  slides from the first position to the second position, such that the engagement region  2557  of release arm  2558  ride along a cam slot  2554  of button  2555 . Cam slot  2554  of button  2555  has a first end  2554   a  and a second end  2554   b , wherein when button  2555  is in the first position the engagement region  2557  of release arm  2558  is disposed at the first end  2554   a  of cam slot  2554  and the abutment region  2556  of release arm  2558  is spaced away from lock plate  2552 . When button  2555  is in the second position the engagement region  2557  of release arm  2558  is disposed at the second end  2554   b  of cam slot  2554  and abutment region  2556  of release arm  2558  is in abutment with lock plate  2552 . Accordingly, as engagement region  2557  cams along cam slot  2554 , abutment region  2556  of release arm  2558  comes into and out of abutment with lock plate  2552 , thus transitioning lock plate  2552  between the locked and unlocked configurations, respectively. 
     It is envisioned that the transition of button  2555  from the first position to the second position may correspond to the transitioning of lock plate  2552  into the unlocked configuration. It is contemplated that retention mechanism  2550  may further include a biasing member  2559  disposed in locking cavity  2551 , such that lock plate  2552  is biased to the locked configuration. It is further contemplated that button  2555  may include a biasing member (not shown) supported thereon such that button  2555  is biased to the first position. 
     With continued reference to  FIGS. 18A-19D , coupling and uncoupling of instrument sleeve  1010  of surgical instrument  1000  to retention mechanism  2550  of instrument drive assembly  2000  will be discussed. During coupling of instrument sleeve  1010  to retention mechanism  2550 , instrument sleeve  1010  is inserted into distal opening  2404  of coupling tube and slid proximally therein ( FIG. 18A ). As the proximal end  1011  of instrument sleeve  1010  approaches the proximal end  2402  of coupling tube  2400 , the proximal end  1011  of instrument sleeve  1010  urges lock plate  2551  to transition into the unlocked configuration (e.g., through-hole  2553  is coaxial with longitudinal axis “T” of coupling tube  2400 ) ( FIG. 18B ). As instrument sleeve  1010  continues to slide proximally, lock plate  2552  aligns with recess  1015  of instrument sleeve  1010 , such that lock plate  2552  is permitted to transition into the locked configuration (e.g., through-hole  2553  is offset or angled from longitudinal axis “T” of coupling tube  2400 ) ( FIG. 18C ). With lock plate  2551  engaged within recess  1015  of instrument sleeve  1010 , longitudinal translation of instrument sleeve  1010 , within coupling tube  2400 , is inhibited. 
     During uncoupling of instrument sleeve  1010  of surgical instrument  1000  from retention mechanism  2550  of instrument drive assembly  2000 , button  2555  is transitioned into the second position, such that engagement region  2557  of release arm  2558  cams along cam slot  2554  of button  2555  into the second end  2554   b  of cam slot  2554  ( FIGS. 19A and 19B ). With engagement region  2557  at the second end  2554   b  of cam slot  2554 , abutment region  2556  of release arm  2558  is brought into abutment with lock plate  2552 , urging lock plate  2551  into the unlocked configuration (e.g., through-hole  2553  is coaxial with longitudinal axis “T” of coupling tube  2400 ) ( FIG. 19B ). With lock plate  2551  in the unlocked configuration, lock plate  2551  is disengaged from recess  1015  of instrument sleeve  1010 , such that instrument sleeve  1010  is free to be withdrawn from and uncoupled from coupling tube  2400  ( FIGS. 19C and 19D ). 
     With reference to  FIGS. 15 and 16 , coupling assembly  2500  of instrument drive assembly  2000  will be discussed. Coupling assembly  2500  is disposed in cavity  2020  of housing assembly  2005  and supported by drive plate  2350 . Coupling assembly  2500  serves to releasably couple instrument drive shaft  1020  of surgical instrument  1000  to drive assembly  2300  of housing assembly  2005 . Coupling assembly  2500  engages with mounting bracket  2370  of drive plate  2350 , which as noted above, extends distally from the distal facing surface  2371  of drive plate  2350 . 
     Mounting bracket  2370  of drive plate  2350  is configured to pivotably support a drive link  2510  thereon, where drive link  2510  is configured to engage with, and couple to, instrument drive shaft  1020  of surgical instrument  1000 , as discussed below. Mounting bracket  2370  includes a pair of receiving arms  2374 , where receiving arms  2374  are spaced apart from one another and define a receiving nook or through-hole  2372  therein, where through-hole  2372  of each receiving arm  2374  is aligned such that a first pin  2376  may be disposed therein. Drive link  2510  is configured to be received between receiving arms  2374  of mounting bracket  2370 , and is pivotably couple thereto via first pin  2376 . First pin  2376  passed through each through-hole  2372  of receiving arms  2374  and a cam slot  2512  of drive link  2510 . It is envisioned that drive link  2510  may alternatively be coupled to mounting bracket  2370  via a pair of extrusions or bosses extending from alternate sides of drive link  2510 . 
     Drive link  2510  of coupling assembly  2500  further defines a through-hole  2514  therein, such that a second pin  2378  couples drive link  2510  to a through-hole  2407  disposed on a proximal portion  2408  of coupling tube  2400 . It is envisioned that through-hole  2407  of coupling tube  2400  may be transverse to longitudinal axis “C” of housing assembly  2005 . As such, when coupled, drive link  2510  is pivotably coupled to coupling tube  2400  between a locked position and an unlocked position, with respect to instrument drive shaft  1020  of surgical instrument  1000 . More specifically, as drive plate  2350  of drive assembly  2300  translates proximally or distally, as discussed above, first pin  2376  rides along cam slot  2512  of drive link  2510  directing drive link  2510  to pivot about second pin  2378 . 
     With reference to  FIGS. 21A and 21B , drive link  2510  of coupling assembly  2500  further defines a receiving region  2516  disposed on a distal facing surface thereof, which is configured to releasably retain and secure coupling ball  1022  of instrument drive shaft  1020 . Receiving region  2516  of drive link  2510  defines a cavity  2517  therein, a port  2518  extending into cavity  2517 , and a channel  2519  extending along cavity  2517 . Receiving region  2516  of drive link  2510  acts as a socket joint for coupling ball  1022  of instrument drive shaft  1020 , where coupling ball  1022  can only enter and exit cavity  2517  through port  2518 . Through pivoting of drive link  2510  between the unlocked and locked positions, port  2518  is correspondingly oriented to be aligned with, or brought off axis of, or angled from, longitudinal axis “T” of coupling tube  2400 , respectively. More specifically, with drive link  2510  in the unlocked position, port  2518  is aligned with longitudinal axis “T”, such that coupling ball  1022  of instrument drive shaft  1020  may be received therein. Once drive link  2510  is pivoted to the locked position, port  2518  is brought off-axis of, or angled from, longitudinal axis “T” of coupling tube  2400 , and coupling ball  1022  of instrument drive shaft  1020  is captured within cavity  2517 . In the locked position, neck  1024  of instrument shaft  1020  resides in channel  2519  of receiving region  2516  of drive link  2510 , where channel  2519  is configured to be smaller than a diameter of coupling ball  1022 , thus locking coupling ball  1022  in cavity  2517  of receiving region  2516  of drive link  2510 . As such, port  2518  of receiving region  2516  of drive link  2510  is configured to receive coupling ball  1022  of instrument drive shaft  1020  therethrough, while channel  2519  of receiving region  2516  of drive link  2510  is configured to inhibit coupling ball  1022  from leaving cavity  2517 . With reference to  FIGS. 21A and 21B , coupling ball  1022  (shown in phantom) is disposed in cavity  2517  of receiving region  2516  and neck  1024  is disposed in channel  2519 . 
     With reference to  FIGS. 20A-20C , the engagement of instrument drive shaft  1020  of surgical instrument  1000  to coupling assembly  2500  of instrument drive assembly  2000  will be discussed. As discussed above, proximal and distal translation of drive plate  2350  of drive assembly  2300  pivots drive link  2510  between the unlocked position and the locked position, such that coupling assembly  2500  transitions between the unlocked and locked configuration, respectively. With drive plate  2350  in a distal most position, coupling assembly  2500  is in the unlocked configuration, drive link  2510  is in the unlocked position, such that port  2518  of drive link  2510  is aligned with longitudinal axis “T” of coupling tube  2400  ( FIG. 20A ). With port  2518  aligned with longitudinal axis “T”, instrument drive shaft  1020  is inserted into the distal end  2404  of coupling tube  2400  and translated proximally, such that coupling ball  1022  of instrument drive shaft  1020  is brought into approximation with port  2518  of receiving region  2516  of drive link  2510 . As instrument drive shaft  1020  translates proximally, coupling ball  1022  is inserted through port  2518  and brought into cavity  2517  of retention region  2516  of drive link  2510  ( FIG. 20B ). With coupling ball  1022  residing in cavity  2517 , drive plate  2350  is translated proximally. As drive plate  2350  is translated proximally, first pin  2376  rides along cam slot  3512  of drive link  2510 , such that drive link  2510  pivots about second pin  2378  into the locked position. With drive link  2510  in the locked position, neck  1024  of instrument shaft  1020  is disposed in channel  2519  of drive link  2510 , thus capturing coupling ball  1022  within cavity  2517  of receiving region  2516  of drive link  2510  ( FIG. 20C ). Further, in the locked position, port  2518  of receiving region  2516  of drive link  2510  is brought off axis of, or angled from, the longitudinal axis “T” of coupling tube  2400 . With drive link  2510  pivoted into the locked position, coupling assembly  2500  is thus in the locked configuration, with respect to instrument drive shaft  1020 . Further proximal movement of drive plate  2350  causes drive link  2510  to pivot past the locked position directing proximal translation of instrument drive shaft  1020 . Accordingly, proximal translation of drive plate  2350  causes drive plate  2510  to pivot past the locked position, thus directing proximal translation of instrument drive shaft  1020 , which actuates the end effector (not shown) disposed at the distal end of instrument drive shaft  1020 . 
     With reference to  FIGS. 19A-20C , a complete coupling and decoupling of instrument drive assembly  2000  to surgical instrument  1000  will be briefly discussed. Initially, instrument sleeve  1010  of surgical instrument  1000  is inserted into coupling tube  2400  of housing assembly  2005  and translated proximally until lock plate  2552  of retention mechanism  2550  is brought into engagement with recess  1015  of instrument sleeve  1010 , thus inhibiting any further translation of instrument sleeve  1010 . It should be appreciated that coupling of instrument sleeve  1010  and retention mechanism  2550  may be performed with button  2555  of retention mechanism in either the first or second position. Next, drive plate  2350  of drive assembly  2300  is translated into a distal most position, such that drive link  2510  is pivoted into the unlocked position. Instrument drive shaft  1020  is then inserted proximally through instrument sleeve  1010  until coupling ball  1022  is engaged with drive link  2510 . It is envisioned that instrument sleeve  1010  may alternatively be omitted, and thus instrument drive shaft  1020  may be inserted directly through coupling tube  2400 . Once coupling ball  1022  is disposed in receiving region  2516  of drive link  2510 , drive plate  2350  is translated proximally, such that drive link  2510  is pivoted into the locked position, and coupling assembly  2500  is translated into the locked configuration. Once instrument drive shaft  1020  is coupling with drive plate  2350 , via drive link  2510 , further proximal translation of drive plate  2350  directs actuation, articulation, or firing of the end effector of surgical instrument  1000 . 
     During decoupling, drive plate  2350  of drive assembly  2300  is returned to the distal most position, such that drive link  2510  pivots to the unlocked position, and coupling assembly  2500  translates into the unlocked configuration. Instrument drive shaft  1020  of surgical instrument  1000  may now by translated distally, such that coupling ball  1022  is brought out of, or withdrawn from, receiving region  2516  of drive link  2510 , and decoupled from instrument drive assembly  2000 . Button  2555  of retention mechanism  2550  may then be translated into the second position, such that release arm  2558  abuts lock plate  2552 , thus urging lock plate  2552  out of engagement with recess  1015  of instrument sleeve  1010  of surgical instrument  1000 . Instrument sleeve  1010  may now be translated distally and withdrawn from coupling tube  2400 . It is envisioned that outer sleeve  1010  and instrument drive shaft  1020  may be configured to be coupled, and uncoupled, independently and/or in any order. 
     During use of instrument drive assembly  2000 , it should be appreciated that rotation of proximal gear  2310  of drive assembly  2300  in a first direction (e.g., clockwise) causes drive screw  2340  to rotate in a corresponding first direction, drive plate  2350  to translate in a first longitudinal direction (proximally), and drive link  2510  to pivot (towards the locked position as illustrated in  FIG. 20C ). Further translation of drive plate  2350  in the first longitudinal direction causes drive link  2510  to continue to pivot, past the locked position, such that instrument drive shaft  1020  is translated in the first longitudinal direction. Similarly, rotation of proximal gear  2310  of drive assembly  2300  in a second direction (e.g., counter-clockwise) causes drive screw  2340  to rotate in a corresponding second direction, drive plate  2350  to translate in a second longitudinal direction (distally), and drive link  2510  to pivot (towards the unlocked position as illustrated in  FIG. 20B ). As drive link  2510  pivots from a position past the locked position towards the locked position, instrument drive shaft  1020  is driven in the second longitudinal direction. Further translation of drive plate  2350  in the second longitudinal causes drive link  2510  to pivot into the unlocked position, such that instrument drive shaft  1020  may be decoupled therefrom. 
     With reference to  FIGS. 22-31B , another embodiment of an instrument drive assembly in accordance with the present disclosure will be described with reference to instrument drive assembly  3000 . Engagement and driving of instrument drive assembly  3000  and medical work station  1  are similar to that of instrument drive assembly  2000 , and thus only difference and distinctions of instrument drive assembly  3000  will be discussed herein below. It should be appreciated that instrument sleeve  1010  and instrument drive shaft  1020  of surgical instrument  1000  may also be releasably coupled with instrument drive assembly  3000 . 
     With reference to  FIGS. 22-26 , instrument drive assembly  3000  includes a housing assembly  3005  having a first side  3001  and a second side  3002 , where first and second sides  3001 ,  3002  define a cavity  3020  therebetween. Housing assembly  3005  further includes a proximal end plate  3010  supported at a proximal end  3003  thereof, a distal end plate  3030  supported at a distal end  3004  of housing assembly  3005 , a drive assembly  3300  ( FIG. 25 ) supported in cavity  3020 , an internal plate  3040  supported in cavity  3020 , a retention mechanism  3550  disposed in cavity  3020 , a coupling tube  3400  supported by distal end plate  3030 , and a coupling assembly  3500  ( FIGS. 30A-31B ) disposed in cavity  3020 . Housing assembly  3005  further includes a release mechanism  3006  disposed on first side  3001 , second side  3002 , and/or both first and second sides  3001 ,  3002 . In a similar fashion as housing assembly  2005  of instrument drive assembly  2000 , release mechanism  3006  of housing assembly  3005  serves to provide a quick and easy means for decoupling instrument drive assembly  3000  from instrument control unit  100 . 
     Proximal end plate  3010  of housing assembly  3005  defines at least one through-hole  3011  therethrough, and in an embodiment it is envisioned that proximal end plate  3010  may define four through-holes  3011  therethrough. Each through-hole  3011  is configured to receive a proximal gear  3310  of drive assembly  3300  therethrough, such that proximal gear  3310  may engage the instrument control gear of instrument control unit  100 . 
     Distal end plate  3030  of housing assembly  3005  defines an elongated cavity  3034 , such that elongated cavity  3034  extends inward from an outer edge  3038  of distal end plate  3030  to align with a longitudinal axis “E” of housing assembly  3005  ( FIG. 26 ). It is envisioned that elongated cavity  3034  of distal end plate  3030  of housing assembly  3005  defines a generally “U” shaped cavity or profile configured to support coupling tube  3400 , such that coupling tube  3400  is supported therein and extends distally from cavity  3020  of housing assembly  3005 . 
     Internal plate  3040  of housing assembly  3005  defines a central through-hole  3042  which is coaxial with the longitudinal axis “E” of housing assembly  3005 , at least one bearing cavity  3044  ( FIG. 26 ) laterally offset from longitudinal axis “E” and which is coaxial with a respective through-hole  3011  of proximal end plate  3010 , and a central cavity  3046  disposed along a proximal surface  3045  of internal plate  3040  which is coaxial with central through-hole  3042  and defines a larger diameter with respect to central through-hole  3042 . A side edge  3048  of internal plate  3040  is supported within first and second sides  3001 ,  3002  of housing assembly  3005  and engages at least one stop member  3021  extending from an inner surface  3022  of both first and second sides  3001 ,  3002  of housing assembly  2005 , such that internal plate  3040  is captured within housing assembly  3005  and linearly fixed therein. It is envisioned that internal plate  3040  provides structural support for housing assembly  3005 , and further provides support for drive assembly  3300 . 
     With reference to  FIGS. 22-26 , drive assembly  3300  includes an engagement assembly  3302  and a transfer assembly  3304 . As illustrated, drive assembly  3300  includes two engagement assemblies  3302 , however, any number engagement assemblies  3302  are envisioned herein. Each engagement assembly  3302  includes a coupling rod  3309 , a proximal gear  3310 , a proximal bearing  3320 , a distal bearing  3330 , and a distal gear  3340  disposed between proximal bearing  3320  and distal bearing  3330 . 
     Coupling rod  3309  includes a proximal portion  3307  and a distal portion  3308 , and defines a longitudinal axis “F” extending through a radial center thereof ( FIG. 25 ). Proximal gear  3310  is configured to engage with the instrument control gear (e.g., crown gear “CG” of motor “M”) of instrument control unit  100 , such that rotation of crown gear “CG” causes a corresponding rotation of proximal gear  3310 . Proximal gear  3310  may be a crown gear “CG” that is configured to mate with and/or mesh with crown gear “CG” of motor “M.” Proximal gear  3310  includes an aperture  3312  extending longitudinally therethrough configured to mechanically engage proximal portion  3307  of coupling rod  3309 . As illustrated, aperture  3312  and proximal portion  3307  of coupling rod  3309  have corresponding, non-circular cross-sections, such that proximal gear  3310  and coupling rod  3309  are keyed to one another, which results in a rotationally fixed connection therebetween. Rotation of proximal gear  3310  causes coupling rod  3309  to rotate about longitudinal axis “F” of coupling rod  3309  in a corresponding direction and rate of rotation. Distal gear  3340  is coupled to distal portion  3308  of coupling rod  3309  and may be keyed, or otherwise rotationally fixed with respect to coupling rod  3309  in a similar manner as proximal bearing  3310 , such that rotation of coupling rod  3309 , via rotation of proximal gear  3310 , directs distal gear  3340  to rotate in a corresponding direction and rate of rotation. Alternatively, distal gear  3340  may be monolithically formed with coupling rod  3309 , such that coupling rod  3309  extends proximally therefrom. 
     Transfer assembly  3304  of drive assembly  3300  includes a central gear  3350 , a stem  3352  extending distally from central gear  3350 , a proximal bearing  3353 , and a distal bearing  3354 . Stem  3352  defines a recess  3355  therein which extends proximally from a distal end  3351  of stem  3352 . Central gear  3350  is positioned between internal plate  3040  and proximal end plate  3010 . Proximal bearing  3353  is interposed between central gear  3350  and proximal end plate  3010 , and distal bearing  3354  is positioned about stem  3352  and interposed between stem  3352  of central gear  3350  and central cavity  3046  of internal plate  3040 . As such, central gear  3350  is longitudinally fixed within housing assembly  3005 , rotatable about longitudinal axis “E” ( FIG. 26 ) of housing assembly  3005 , and is laterally offset from longitudinal axis “F” ( FIG. 25 ) of engagement assembly  3302  defined by coupling rod  3309 . Central gear  3350  is configured to engage and mesh with distal gear  3340  of engagement assembly  3302 , such that rotation of distal gear  3040 , via rotation of proximal gear  3310 , corresponds to a rotation of central gear  3350 . It should be appreciated that stem  3352  and central gear  3350  may be rotationally fixed, or monolithically formed, such that rotation of central gear  3350  directs stem  3252  to rotate in a corresponding direction and rate of rotation. 
     With continued reference to  FIGS. 24-26 , drive assembly  3300  further includes a coupler  3360 , a drive screw  3370 , a stop cap  3376 , and a clip  3378 . Coupler  3360  defines a threaded aperture  3362  and a key feature  3364  on an external surface  3365  thereof. Coupler  3360  is disposed within recess  3355  of stem  3352  of central gear  3350 , and is linearly and rotationally fixed therewith. Key feature  3364  mates with a corresponding key feature  3356  of recess  3355  such that rotation of central gear  3350  directs coupler  3360  to rotate in a corresponding direction and rate of rotation. Drive screw  3370  includes a threaded portion  3372  disposed about a proximal portion  3371  thereof configured to engage threaded aperture  3362  of coupler  3360 , and a coupling feature  3374  disposed at a distal portion  3373  thereof. Thus, coupler  3360  interconnects drive screw  3370  and central gear  3350 . Distal portion  3373  of drive screw  3370  extends distally from coupler  3360 , such that coupling feature  3374  is positioned within a proximal portion  3036  of elongated cavity  3034  of distal end plate  3030 . Drive assembly  3300  may further include a drive spring  3380  disposed about drive screw  3370  and interposed between internal plate  3040  and stop cap  3376  or a proximal edge  3032  of elongated cavity  3034  of distal end plate  3030 . Drive spring  3380  serves to dampen the linear translation of drive screw  3370 . 
     Coupling feature  3374  of drive screw  3370  engages coupling assembly  3500 . With brief reference to  FIG. 24 , distal end plate  3030  pivotably supports coupling assembly  3500  thereon. Coupling assembly  3500  of instrument drive assembly  3000  is configured to mechanically engage instrument drive shaft  1020  of surgical instrument  1000 , such that proximal and distal translation of drive screw  3370 , with respect to coupler  3360 , results in proximal and distal translation of instrument drive shaft  1020 . Linear translation of drive screw  3370  is configured to drive a function of the end effector of surgical instrument  1000  in a similar fashion as drive member  380  of instrument drive assembly  200 , and drive plate  2350  of instrument drive assembly  2000 , and thus will not be discussed in any further detail herein. Linear translation of drive screw  3370  further directs locking and unlocking of coupling assembly  3500  with respect to instrument drive shaft  1020 . 
     During rotation of coupler  3360 , via rotation of central gear  3350 , threaded aperture  3362  of coupler  3360  engages and drives threaded portion  3372  of drive screw  3370 . As coupler  3360  is caused to rotate about longitudinal axis “E” of housing assembly  3005 , drive screw  3370  translates linearly with respect to coupler  3360 . Thus, rotational motion of central gear  3350 , via engagement assembly  3302 , is transferred into linear motion of drive screw  3370 , via engagement between threated aperture  3362  of coupler  3360  and threaded portion  3372  of drive screw  3370 . Accordingly, as central gear  3340  rotates about longitudinal axis “E”, coupler  3360  also rotates about longitudinal axis “E”, and drive screw  3370  engaged therewith is caused to translate linearly, with respect to coupler  3360 , along longitudinal axis “E” as a result of the threaded relationship therebetween. 
     A stop cap  3376  is disposed about drive screw  3370  distal of threaded portion  3372 , such that proximal portion  3371  of drive screw  3370  may slide linearly within a through-hole  3375  of stop cap  3376 . A clip  3378  is disposed about drive screw  3370  distal of stop cap  3376 , and is configured to engage recess  3377  defined on drive screw  3370 . It should be appreciated that clip  3378  affixes stop cap  3376  at a position between threaded portion  3372  and coupling feature  3374 . Further, stop cap  3376  and clip  3378  engage a recess  3031  disposed on proximal edge  3032  of elongated cavity  3034  of distal end plate  3030 . During linear translation of drive screw  3370 , with respect to coupler  3360 , stop cap  3376  defines a maximum distal position of drive screw  3370 . More particularly, with stop cap  3376  engaged with recess  3031  of distal end plate  3030 , as drive screw  3370  translates distally to a maximum distal position, threaded portion  3372  thereof comes into abutment with stop cap  3376 , whereby stop cap  3376  is linearly fixed via clip  3378  and engagement with distal end plate  3030 , thus inhibiting further distal translation of drive screw  3370 . 
     With continued reference to  FIGS. 24 and 26 , housing assembly  3005  includes a coupling tube  3400 . Coupling tube  3400  extends distally from housing assembly  3005  and is configured to receive instrument sleeve  1010  and instrument drive shaft  1020  of surgical instrument  1000  in a similar manner to that of coupling tube  2400  of instrument drive unit  2000 . Coupling tube  3400  includes a proximal end  3402  defining a through-hole  3403 , and a longitudinal bore or lumen  3405  extending distally therefrom. It is envisioned that longitudinal bore  3405  defines a larger diameter than through-hole  3403 , such that longitudinal bore  3405  is configured to receive both instrument sleeve  1010  and instrument drive shaft  1020  of surgical instrument  1000  therein, and through-hole  3403  is configured to receive only instrument drive shaft  3020  therethrough. Coupling tube  3400  is supported in elongated cavity  3034  of distal end plate  3030  of housing assembly  3005  such that a distal portion  3401  of coupling tube  3400  extends distally therefrom. It is envisioned that coupling tube  3400  may be monolithically formed with distal end plate  3030 , or may alternatively be releasably couplable to elongated cavity  3034 , such that coupling tube  3400  slides into and out of engagement with elongated cavity  3030 . Longitudinal bore  3405  and through-hole  3403  of coupling tube  3400  define a longitudinal axis “G” of coupling tube  3400  ( FIG. 24 ), which may be coaxial with longitudinal axis “E” of housing assembly  3005 . Longitudinal bore  3405  is configured to slidingly receive proximal portion  1009  of instrument sleeve  1010 . It is envisioned that during coupling of surgical instrument  1000  with instrument drive assembly  3000 , coupling tube  3400  may aid alignment of instrument drive shaft  1020  and drive assembly  3300 . More specifically, instrument sleeve  1010  of surgical instrument  1000  is slidably inserted into a distal opening  3404  of coupling tube  3400 . When instrument sleeve  1010  of surgical instrument  1000  is fully inserted into longitudinal bore  3405  of coupling tube  3400 , proximal end  1011  of instrument sleeve  1010  abuts a distally facing surface of proximal end  3402  of coupling tube  3400 . 
     Housing assembly  3005  further includes a retention mechanism  3550  configured to releasably retain or secure instrument sleeve  1010  of surgical instrument  1000  to coupling tube  3400 , and thus to housing assembly  3005 . With reference to  FIGS. 24-29C , retention mechanism  3550  includes a latch plate  3552 , a button  3555 , and a cam arm  3558  extending from button  3555 . Coupling tube  3400  of housing assembly  3005  defines a locking cavity  3551  disposed distal of proximal end  3402  which extends into longitudinal bore  3405 . Latch plate  3552  includes an arm  3553  and a pivot recess  3554 . Pivot recess  3554  is configured to pivotably couple with a pivot stem  3039  of distal end plate  3030  being laterally off-set from longitudinal axis “E” of housing assembly  3005 , whereby pivot stem  3039  extends distally from distal end plate  3030 . More particularly, latch plate  3552  pivots about pivot recess  3554  and pivot stem  3039  transverse to longitudinal axis “E” of housing assembly  3005  and longitudinal axis “G” of coupling tube  3400 . 
     With latch plate  3552  pivotably coupled to pivot stem  3039 , latch plate  3552  is disposed within locking cavity  3551  such that as latch plate  3552  pivots, arm  3553  of latch plate  3552  pivots into and out of alignment with longitudinal bore  3405  of coupling tube  3400 . As such, latch plate  3552  pivots between locked and unlocked configurations, with respect to instrument sleeve  1010 . More specifically, in the locked configuration arm  3553  of latch plate  3552  is positioned within longitudinal bore  3405  of coupling tube  3400  and intersects the longitudinal axis “G” thereof ( FIGS. 27A, 28A, and 28B ), and in the unlocked configuration arm  3553  of latch plate  3552  is positioned out of longitudinal bore  3405  of coupling tube  3400  and is off-axis of, and offset or angled from, the longitudinal axis “G” thereof ( FIGS. 27B, 28C, and 28D ). 
     It should be appreciated that button  3555  acts as an instrument release button similar to that of button  2555  of instrument drive unit  2000 , such that instrument sleeve  1010  is releasably couplable to instrument drive unit  3000 . Button  3555  is slidably coupled to housing assembly  3005  and linearly transitionable between first and second positions with respect to distal end plate  3030 . Linear articulation of button  3555  between first and second positions acts to transition latch plate  3552  between the locked and unlocked configurations, respectively. More particularly, as button  3555  translates proximally from the first position ( FIGS. 27A, 28A, and 28B ) towards the second position ( FIGS. 27B, 28C and 28D ) in the direction of arrow “X”, with respect to distal end plate  3030 , cam arm  3558  of button  3555  engages arm  3553  of latch plate  3552 . As cam arm  3558  engages arm  3553 , arm  3553  is caused to pivot in the direction of arrow “Y” out of longitudinal bore  3405 , bringing latch plate  3552  into the unlocked configuration ( FIGS. 27B, 28C and 28D ) with respect to instrument sleeve  1010 . As should be appreciated, as button  3555  translates distally, with respect to distal end plate  3030 , from the first position towards the second position, cam arm  3558  is disengaged with arm  3553  of latch plate  3552  permitting arm  3553  to pivot into alignment with longitudinal bore  3405  bringing latch plate  3552  into the locked configuration ( FIGS. 27A, 28A, and 28B ) with respect to instrument sleeve  1010 . 
     Retention mechanism  3550  may further include a first biasing member  3557  interposed between latch plate  3552  and coupling tube  3400 , such that latch plate  3552  is biased into or out of locking cavity  3551 , and thus biased into either the locked or unlocked configuration. Further, retention mechanism  3550  may include a second biasing member  3559  interposed between button  3555  and distal end plate  3030 , such that button  3555  is biased into either the first or second position. 
     With continued reference to  FIGS. 27A-29C , coupling and uncoupling of instrument sleeve  1010  of surgical instrument  1000  to retention mechanism  3550  of instrument drive assembly  3000  will be discussed. During coupling of instrument sleeve  1010  to coupling assembly  3500 , instrument sleeve  1010  is inserted into distal opening  3404  of coupling tube  3400  and slid proximally therein ( FIG. 29A ). As the proximal end  1011  of instrument sleeve  1010  approaches proximal end  3402  of coupling tube  3400 , the proximal end  1011  of instrument sleeve  1010  urges arm  3553  of latch plate  3552  to transition into the unlocked configuration (e.g., arm  3553  pivots within locking cavity  3551  of coupling tube  3400  and into a position out of longitudinal bore  3405  and off axis of longitudinal axis “G” of coupling tube  3400 ) ( FIGS. 27B, 28C, 28D, and 29A ). As instrument sleeve  1010  continues to slide proximally, arm  3553  aligns with recess  1015  of instrument sleeve  1010 , such that arm  3553  is permitted to pivot into the locked configuration (e.g., arm  3553  pivots within locking cavity  3551  of coupling tube  3400  and into engagement with recess  1015  of instrument sleeve  1010 ) ( FIG. 29B ). With arm  3553  of latch plate  3552  engaged within recess  1015  of instrument sleeve  1010 , longitudinal translation of instrument sleeve  1010 , within coupling tube  3400 , is inhibited. In an embodiment with first biasing element  3557 , latch plate  3552  may be biased into the locked configuration, such that arm  3553  is biased into engagement with recess  1015  and thus springs into engagement with recess  1015  upon insertion of instrument sleeve  1010 . 
     It should be appreciated that button  3555  may be slide proximally from the first position towards the second position in the direction of arrow “X” during coupling of instrument sleeve  1010  and retention mechanism  3550 , wherein button  3555  is slid distally from the second position towards the first position in the direction of arrow “Z” once instrument sleeve  1010  is fully inserted within coupling tube  3400  and arm  3553  aligns with recess  1015  ( FIG. 29C ). In an embodiment with second biasing element  3559 , button  3555  may be biased towards the first position in the direction of arrow “Z” (e.g., cam arm  3558  is biased out of engagement with arm  3553 ), such that once arm  3553  engages recess  1015  of instrument sleeve  1010  button  3555  springs towards the first position. 
     During uncoupling of instrument sleeve  1010  of surgical instrument  1000  from retention mechanism  3550  of instrument drive assembly  3000 , button  3555  is transitioned from the first position (e.g., the proximal position illustrated in  FIGS. 27A, 28A, 29B, and 29C ) towards the second position (e.g., the distal position illustrated in  FIGS. 27B, 28C, 29A ) in the direction of arrow “X”. As button  3555  slides towards the second position, cam arm  3558  of button  3555  cams along arm  3553  of latch plate  3552 , causing arm  3553  to pivot into a position out of longitudinal bore  3405  and off axis of longitudinal axis “G” of coupling tube  340  into the unlocked configuration (e.g., arm  3553  pivots within locking cavity  3551  of coupling tube  3400  out of engagement with recess  1015  of instrument sleeve  1010 ) ( FIGS. 28D and 29A ). With arm  3553  pivoted out of the recess  1015  of instrument sleeve  1010 , instrument sleeve  1010  is free to be withdrawn from and uncoupled from coupling tube  3400 . 
     With reference to  FIGS. 24 and 25 , coupling assembly  3500  of instrument drive assembly  3000  will be discussed. Coupling assembly  3500  is disposed in cavity  3020  of housing assembly  3005  and is pivotably supported by distal end plate  3030 . Coupling assembly  3500  serves to releasably couple instrument drive shaft  1020  of surgical instrument  1000  to drive assembly  3300 . 
     Coupling assembly  3500  includes a drive link  3510  configured to engage with, and couple to, instrument drive shaft  1020  of surgical instrument  1000 . Drive link  3510  is pivotably coupled to distal end plate  3030  via a set of opposing protrusions  3512  extending therefrom which reside within a slot  3514  defined through distal end plate  3030 . It is envisioned that opposing protrusions  3512  may be monolithically formed with drive link  3510 , or alternatively, may define a pin which passes therethrough to reside within slot  3514 . A pin  3516  couples drive link  3510  and coupling feature  3374  of drive screw  3370 , such that pin  3516  passes through a pinhole  3515  of drive ink  3510  and coupling feature  3374 . In such an embodiment, coupling feature  3374  may define a through-hole  3379  which may be transverse to longitudinal axis “E” of housing assembly  3005 . In an embodiment, coupling feature  3374  may define a boss or protrusion which engages pinhole  3515 , thereby coupling drive screw  3370  and drive link  3510 . 
     As such, when coupled, drive link  3510  is pivotably coupled to distal end plate  3030 , via engagement of protrusions  3512  of drive link  3510  and slot  3514  of distal end plate  3030 , and pivotably coupled to drive screw  3370 , via engagement of pin  3516  and through-hole  3379  of coupling feature  3374  of drive screw  3370 . Thus, drive link  3510  is transitionable between a locked position ( FIG. 30C ) and an unlocked position ( FIGS. 30A and 30B ), with respect to instrument drive shaft  1020  of surgical instrument  1000 . More specifically, as drive screw  3370  of drive assembly  3300  translates proximally or distally, as discussed above, drive link  3510  is caused to pivot about protrusions  3512 . Accordingly, similar to that of instrument drive unit  2000 , instrument drive shaft  1020  may be coupled and uncoupled from instrument drive unit  3000  through the cooperation of the linear translation of drive screw  3370  and the pivoting of drive link  3510 . 
     With reference to  FIGS. 31A and 31B , drive link  3510  of coupling assembly  3500  further defines a receiving region  3518  disposed on a distal facing surface thereof, which is configured to releasably retain and secure coupling ball  1022  of instrument drive shaft  1020 . Receiving region  3518  of drive link  3510  defines a cavity  3520  therein, a port  3522  extending into cavity  3520 , and a channel  3524  extending along cavity  3520 . Receiving region  3518  of drive link  3510  acts as a socket joint for coupling ball  1022  of instrument drive shaft  1020 , where coupling ball  1022  can only enter and exit cavity  3520  through port  3522 . Through pivoting of drive link  3510  between the unlocked and locked positions, port  3522  is correspondingly oriented to be aligned with, or brought off axis of, or angled from, the longitudinal axis “G” of coupling tube  3400 , respectively. More specifically, with drive link  3510  in the unlocked position ( FIGS. 30A and 30  B), port  3522  is aligned with longitudinal axis “G”, such that coupling ball  1022  of instrument drive shaft  1020  may be received therein. Once drive link  3510  is pivoted to the locked position ( FIGS. 30C-31B ), port  3522  is brought off-axis of, or angled from, longitudinal axis “G” of coupling tube  3400 , and coupling ball  1022  of instrument drive shaft  1020  is captured within cavity  3520 . In the locked position, neck  1024  of instrument shaft  1020  resides in channel  3524  of receiving region  3518  of drive link  3510 , where channel  3524  is configured to be smaller than a diameter of coupling ball  1022 , thus capturing coupling ball  1022  within cavity  3520  of receiving region  3518  of drive link  3510 . As such, port  3522  of receiving region  3518  of drive link  3510  is configured to receive coupling ball  1022  of instrument drive shaft  1020  therethrough, while channel  3524  of receiving region  3518  of drive link  3510  is configured to inhibit coupling ball  1022  from leaving cavity  3520 . With reference to  FIGS. 31A and 31B , coupling ball  1022  (shown in phantom) is disposed in cavity  3520  of receiving region  3518  and neck  1024  is disposed in channel  3524 . 
     With reference to  FIGS. 30A-30C , the engagement of instrument drive shaft  1020  of surgical instrument  1000  to coupling assembly  3500  of instrument drive assembly  3000  will be discussed. As discussed above, proximal and distal translation of drive screw  3370  of drive assembly  3300  pivots drive link  3510  between the unlocked and locked positions, such that coupling assembly  3500  transitions between the unlocked and locked configuration, respectively. With drive screw  3370  in a distal most position, drive link  3510  is in the unlocked position and coupling assembly  3500  is in the unlocked configuration, such that port  3522  of drive link  3510  is aligned with longitudinal axis “G” of coupling tube  3400  ( FIGS. 30A and 30B ). With port  3522  aligned with longitudinal axis “G”, instrument drive shaft  1020  is inserted into the distal opening  3404  of coupling tube  3400  and translated proximally, such that coupling ball  1022  of instrument drive shaft  1020  is brought into approximation with port  3522  of receiving region  3518  of drive link  3510 . As instrument drive shaft  1020  translates proximally, coupling ball  1022  is inserted through port  3522  and brought into cavity  3520  of retention region  3518  of drive link  3510  ( FIG. 30B ). With coupling ball  1022  residing in cavity  3520 , drive screw  3370  is translated proximally. As drive screw  3370  is translated proximally, drive link  3510  pivots about protrusions  3512  into the locked position. With drive link  3510  in the locked position, neck  1024  of instrument shaft  1020  is disposed in channel  3524  of drive link  3510 , thus capturing coupling ball  1022  within cavity  3520  of receiving region  3518  of drive link  3510  ( FIG. 30C ). Further, in the locked position, port  3522  of receiving region  3518  of drive link  3510  is brought off axis of, or angled from, the longitudinal axis “G” of coupling tube  3400 . With drive link  3510  pivoted into the locked position coupling assembly  3500  is thus in the locked configuration with respect to instrument drive shaft  1020 . With coupling assembly  3500  in the locked configuration, further proximal movement of drive screw  3370  causes drive link  3510  to pivot past the locked position directing proximal translation of instrument drive shaft  1020 . Accordingly, proximal translation of drive screw  3370  causes drive link  3510  to pivot past the locked position, thus directing proximal translation of instrument drive shaft  1020 , which actuates the end effector (not shown) disposed at the distal end of instrument drive shaft  1020 . 
     With reference to  FIGS. 27A-31B , a complete coupling and decoupling of instrument drive assembly  3000  to surgical instrument  1000  will be briefly discussed. Initially, instrument sleeve  1010  of surgical instrument  1000  is inserted into coupling tube  3400  of housing assembly  3005  and translated proximally until arm  3553  of latch plate  3552  of retention mechanism  3550  is brought into engagement with recess  1015  of instrument sleeve  1010 , thus inhibiting any further translation of instrument sleeve  1010 . It should be appreciated that coupling of instrument sleeve  1010  and retention mechanism  3550  may be performed with button  3555  of retention mechanism  3550  in either the first or second position. Next, drive screw  3370  of drive assembly  3300  is translated into a distal most position, such that drive link  3510  is pivoted into the unlocked position and coupling assembly  3500  is brought into the unlocked configuration. Instrument drive shaft  1020  is then inserted proximally through instrument sleeve  1010  until coupling ball  1022  is engaged with drive link  3510 . Alternatively, it is envisioned that instrument sleeve  1010  may be omitted, and thus instrument drive shaft  1020  may be inserted directly through coupling tube  3400 . Once coupling ball  1022  is disposed in receiving region  3518  of drive link  3510 , drive screw  3370  is translated proximally, such that drive link  3510  is pivoted into the locked position, and coupling assembly  3500  is translated into the locked configuration. Once instrument drive shaft  1020  is coupling with drive link  3510 , further proximal translation of drive screw  3370  directs actuation, articulation, or firing of the end effector of surgical instrument  1000 . 
     During decoupling, drive screw  3370  of drive assembly  3300  is returned to the distal most position, such that drive link  3510  pivots to the unlocked position, and coupling assembly  3500  transitions into the unlocked configuration. Instrument drive shaft  1020  of surgical instrument  1000  may now by translated distally, such that coupling ball  1022  is brought out of, or withdrawn from, receiving region  3518  of drive link  3510 , and decoupled from instrument drive assembly  3000 . Button  3555  of retention mechanism  3500  may then be translated from the first position (e.g., distal position) towards the second position (e.g., proximal position), such that cam arm  3558  of button  3555  engages and pivots arm  3553  of latch plate  3552  out of engagement with recess  1015  of instrument sleeve  1010  of surgical instrument  1000 . Instrument sleeve  1010  may now be translated distally and withdrawn from coupling tube  3400 . It is envisioned that outer sleeve  1010  and instrument drive shaft  1020  may be configured to be coupled, and uncoupled, independently and/or in any order. 
     During use of instrument drive assembly  3000 , it should be appreciated that rotation of proximal gear  3310  of drive assembly  3300  in a first direction (e.g., clockwise) causes central gear  3350  to rotate in an opposing direction, which directs drive screw  3370  to translate in a first linear direction (e.g., proximally), and pivots drive link  3510  (e.g., towards the locked position as illustrated in  FIG. 30C ). Further translation of drive screw  3370  in the first linear direction causes drive link  3510  to continue to pivot, past the locked position, such that instrument drive shaft  1020  is translated in the first linear direction. Similarly, rotation of proximal gear  3310  of drive assembly  3300  in a second direction (e.g., counter-clockwise) causes central gear  3350  to rotate in an opposing direction, which directs drive screw  3370  to translate in a second linear direction (e.g., distally), and pivots drive link  3510  (e.g., towards the unlocked position as illustrated in  FIGS. 30A and 30B ). As drive link  3510  pivots from a position past the locked position towards the locked position, instrument drive shaft  1020  is driven in the second linear direction. Further translation of drive screw  3370  in the second linear direction causes drive link  3510  to continue pivoting into the unlocked position, such that instrument drive shaft  1020  may be decoupled therefrom. 
     It is contemplated that instrument sleeve  1010  of surgical instrument  1000  may further include a flush or inflation port  1080  disposed distally of proximal end  1011  ( FIG. 11 ) of instrument sleeve  1010 . Port  1080  may be used to introduce fluids into or out of the surgical site through longitudinal lumen  1012  of instrument sleeve  1010 . Port  1080  may further be used as an alignment feature, such that at least one recess  900  or  3900  disposed along distal opening  2404  of coupling tube  2400 , or a distal opening  3404  of coupling tube  3400  respectively, acts as a keying feature for instrument sleeve  1010  and/or instrument drive shaft  1020  ( FIGS. 12 and 31A ) of surgical instrument  1000 . It is envisioned that at least two recesses  900 ,  3900  may be included and spaced 180° apart about distal opening  2404  of coupling tube  2400  or distal opening  3404  of coupling tube  3400 . It is envisioned that coupling tube  400  of instrument drive assembly  200  may similarly define a recess disposed along distal opening  404  to serve as a keying feature when coupling instrument drive assembly  200  and instrument sleeve  1010  of surgical instrument  1000 . 
     Further still, instrument drive assembly  3000  may include a controller  3950  disposed within housing assembly  3005  ( FIG. 24 ). It is envisioned that instrument drive assembly  200 ,  2000  and  3000  may further include controller  3950 . Controller  3950  is configured to identify a surgical instrument  1000  coupled thereto, either through a wired or wireless data communication (e.g., Bluetooth®, WiFI®, ZigBee®, RFID, etc.), such that controller  3950  may adjust and tailor the instrument drive assembly  200 ,  2000 , or  3000  for the specific surgical tool  1000 . Controller  3950  may retrieve data pertaining to the operational parameters of the identified surgical tool  1000  from an internal storage medium or an external stored medium, e.g., wired or wireless communication with medical work station  1 . Such data of surgical tool  1000  may include force or torque capabilities, calibration procedures, usage data, serial or identification markers, end effector function and operational parameters, instrument sleeve  1010  and/or instrument drive shaft  1020  length, etc. 
     With reference to  FIGS. 1-31B , a kit will be described. A kit may include one or more instrument drive assemblies  200 , one or more instrument drive assemblies  2000 , one or more instrument drive assemblies  3000 , or any combination thereof. The kit may further include one or more surgical instruments  1000 , where the end effector of each surgical instrument may vary to provide a number of end effector options to a user. It is further envisioned that the kit may include alternate instrument sleeves  1010  and/or instrument drive shafts  1020 , such that the operator may interchange instrument sleeves  1010  and instrument drive shafts  1020  for a given procedure. A variety of instrument sleeves  1010  and/or instrument drive shafts  1020  defining a range of lengths and/or diameters may be provided to the user, such that the user has a variety of sized surgical instrument  1000  available. 
     Referring now to  FIGS. 32-34 , a surgical assembly, generally referred to as  4000  defines a longitudinal axis “L” and includes an instrument drive assembly  4100  and a surgical instrument  4200  that are configured to selectively threadably couple together. Instrument drive assembly  4100  of surgical assembly  4000  is similar to instrument drive assemblies  200 ,  2000 ,  3000 , but includes a coupling tube  4110  supported on a distal end portion of instrument drive assembly  4100 . Coupling tube  4110  of instrument drive assembly  4100  includes a threaded outer surface  4112  configured to threadably couple to a proximal portion of surgical instrument  4200  to axially fix surgical instrument  4200  to instrument drive assembly  4100 . 
     Surgical instrument  4200  of surgical assembly  4000  includes a shaft assembly  4210  that supports a knob  4220  on a proximal end portion thereof and a jaw assembly  4230  on a distal end portion thereof. Jaw assembly  4230  includes a first jaw member  4230   a  and a second jaw member  4230   b  disposed in mirrored relation to first jaw member  4230   b . One or both of first and second jaw members  4230   a ,  4230   b  of jaw assembly  4230  may be movable (e.g., pivotable) relative to one another to enable first and/or second jaw members  4230   a ,  4230   b  to move between an open position ( FIG. 32 ) and a closed position (not shown), as indicated by arrows “P” for treating tissue (e.g., one or more of grasping, cutting, stapling, sealing, etc.) captured by the first and second jaw members  4230   a ,  4230   b.    
     The knob  4220  of surgical instrument  4200  includes a handle portion  4220   a  and nose portion  4220   b  that extends distally from handle portion  4220   a . Knob  4220  further includes an outer surface  4220   c  and an inner surface  4220   d . Outer surface  4220   c  of knob  4220  includes gripping grooves  4220   e  defined along handle portion  4220   a  of knob  4220  to enhance gripping and rotation of handle portion  4220   a  (e.g., relative to coupling tube  4110  of instrument drive assembly  4100 ). Inner surface  4220   d  of knob  4220  defines a bore  4222  through knob  4220  and includes threads  4224  that extend along handle portion  4220   a  about bore  4222 . Threads  4224 , along inner surface  4220   d  of knob  4220 , are configured to threadably couple with threaded outer surface  4112  of coupling tube  4110  of instrument drive assembly  4100 , as indicated by arrows “T,” to enable surgical instrument  4200  and instrument drive assembly  4100  of surgical assembly  4000  to selectively threadably couple together (and/or uncouple, for example, for instrument exchange and/or cleaning/autoclaving of surgical instrument  4200 ). Inner surface  4220   d  of knob  4220  further includes an annular shoulder  4226 . 
     Shaft assembly  4210  of surgical instrument  4200  includes an outer shaft assembly  4212  and an inner shaft  4214 . Outer shaft assembly  4212  of shaft assembly  4210  defines a luer flush port  4212   a  (e.g., to facilitate cleaning) in a proximal end portion thereof that is in fluid communication with a lumen  4212   b  defined by an inner surface of outer shaft assembly  4212 . Lumen  4212   b  of outer shaft assembly  4212  is positioned to receive the inner shaft  4214  therein and extends through outer shaft assembly  4212  from luer flush port  4212   a  to a distal end portion of outer shaft assembly  4212 . Outer shaft assembly  4212  includes a pair of clocking flats  4212   c ,  4212   e  that are positioned to enable outer tube assembly  4212  to engage a complementary feature (not shown, but keyed to rotatably lock with clocking flats  4212   c ,  4212   e ) supported within coupling tube  4110  of instrument drive assembly  4100  so that jaw assembly  4230  of surgical instrument  4200  is maintained in either one of two orientations (e.g., one of two vertical orientations 180 degrees apart). For example, in a first orientation, clocking flat  4212   c  is positioned superiorly of clocking flat  4212   d  such that first jaw member  4230   a  is positioned superiorly of second jaw member  4230   b . In a second orientation, clocking flat  4212   d  is positioned superiorly of clocking flat  4212   e  such that second jaw member  4230   b  is positioned superiorly of first jaw member  4230   a.    
     Although shown and described as vertical orientations, clocking flats  4212   c ,  4212   d  of outer shaft assembly  4212  of surgical instrument  4200 , and/or the first and/or second jaw members  4230   a ,  4230   b  of surgical instrument  4200  can have any number of orientations and/or arrangements with respect to one another (e.g., more than two orientations and/or non-vertical orientations such as lateral and/or inclined/angled orientations, etc. and which may be separated by an suitable angular arc relative to one another). For example, although shown with two clocking positions that are 180 degrees apart, any number of clocking flats may be separated by one or more arc lengths such as 45 degrees, 60 degrees, 90 degrees, 120 degrees, etc. 
     Outer shaft assembly  4212  of surgical instrument  4200  further includes an annular flange  4212   e  that is positioned to abut annular shoulder  4226  of knob  4220  of surgical instrument  4200  to prevent axial movement of outer tube assembly  4212  relative to knob  4220  and/or inner shaft  4214  of surgical instrument  4200 . Outer shaft assembly  4212  also supports an insert lock assembly  4216 . Insert lock assembly  4216  includes a clip  4216   a  (e.g., a C-clip that may include elastomeric materials) that functions to urge and/or radially constrain a lock body  4216   b  (which may include metallic materials) of insert lock assembly  4216  into lumen  4212   b  of outer shaft assembly  4212 . The function of the insert lock assembly  4216  is to prevent relative rotation between inner shaft  4214  (and attached components) and outer shaft assembly  4212  (and attached components). This may be necessary to cause torsional load at one or both of first and second jaw members  4230   a ,  4230   b  of jaw assembly  4230 . Knob  4220  may be advanced proximally/distally to lock/unlock insert lock assembly  4216  to enable a user to exchange tools (e.g., jaw assembly  4230 ), for example. 
     Lock body  4216   b  of insert lock assembly  4216  of outer tube assembly  4214  is retained by clip  4216   a . In particular, clip  4215   a  loads lock body  4216   b  radially inward against outer shaft assembly  4212 . Flats  4212   c ,  4212   e  on inner shaft  4214  of surgical instrument  4200  are provided such that, in some orientations, lock body  4216   b  is forced radially outward. When knob  4220  is advanced proximally, radial outward motion of lock body  4216   b  is prevented, and thus, tool rotation is also prevented. When knob  4220  is advanced distally, radial outward motion of lock body  4216   b  is enabled, and thus, tool rotation (e.g., jaw assembly  4230  rotation) is enabled relative to outer shaft assembly  4212 . This then enables tool (e.g., jaw assembly  4230 ) removal and replacement from outer shaft assembly  4212 . 
     Inner shaft assembly  4214  of surgical instrument  4200  is constructed and operates similar to instrument drive shaft  1020  of surgical instrument  1000  described above (see  FIGS. 8A-10 , for example), but includes a recessed segment  4214   a  that defines proximal and distal abutments  4214   b ,  4214   c  at respective proximal and distal ends thereof. Lock body  4216   b  of insert lock assembly  4216  of outer tube assembly  4214  is positioned to engage proximal and distal abutments  4214   b ,  4214   c  of recessed segment  4214   a  as inner shaft assembly  4214  moves axially relative to outer tube assembly  4214  between proximal and distal positions thereof, as indicated by arrow “N,” to limit axial movement of inner shaft assembly  4214  relative to outer tube assembly  4214 . 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended thereto.