Abstract:
A medical system and an integrated drape assembly for a medical system is provided. The medical system comprises a surgical instrument that carries a distal tool configured for performing a medical procedure on a patient, a drive unit configured for controlling the movement of the surgical instrument within at least one degree-of-freedom, a coupling mechanism through which the surgical instrument is operably coupled to the drive unit, and an integrated drape assembly having a drape insert through which the coupling mechanism is coupled to the surgical instrument, a sterile drape covering the coupling mechanism. The drape assembly may comprise a coupling element mounted within the drape insert. The coupling element may be configured for coupling a driver element of the medical system to a driven element of the medical system.

Description:
RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. application Ser. No. 10/302,804, filed Nov. 21, 2002, which claims benefit of priority from U.S. application Ser. No. 60/409,530, filed Sep. 9, 2002. This application is also related to application Ser. No. xx/xxx,xxx (Attorney Docket No. HNMD-EA007 CON2), filed on the same date herewith. The disclosures of these applications are expressly incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     For certain medical procedures, minimally invasive surgery has replaced conventional surgery where the patient&#39;s body cavity is open to permit the surgeon&#39;s hands and instruments access to the cavity and internal organs. Minimally invasive procedures are typically less traumatic than conventional surgery, in part, because of the significant reduced incision size through which the medical instruments are inserted.  
         [0003]     A video camera may be inserted into the patient in the area of the surgical site to view the procedure. It is, of course, important that the surgeon have some feedback either through a camera and fiber optic cable, or through real-time computerized tomography scan imagery. However, even with such visualization, the surgeon&#39;s tactile and position senses are physically removed from the operative site.  
         [0004]     Some have proposed, therefore, the use of robots in surgery. Although current laparoscopy limits dexterity, and robotics restores dexterity, presently, existing systems, using manipulators both with and without haptic feedback, are generally too bulky and heavy for many minimally invasive procedures, or are too weak and imprecise for surgery.  
       SUMMARY OF THE INVENTION  
       [0005]     In accordance with a first aspect of the present invention, a medical system is provided. The medical system comprises a surgical instrument that carries a distal tool configured for performing a medical procedure on a patient. The medical system further comprises a drive unit (e.g., one having a motor array) configured for controlling the movement of the surgical instrument within at least one degree-of-freedom (e.g., an actuation of the distal tool), and a coupling mechanism through which the surgical instrument is operably coupled to the drive unit. The coupling mechanism may be, e.g., a guide tube through which the surgical instrument is disposed. The medical system further comprises an integrated drape assembly having a drape insert through which the coupling mechanism is coupled to the surgical instrument, and a sterile drape covering the coupling mechanism. In one embodiment, the drape insert is composed of a stiff material.  
         [0006]     In one embodiment, the surgical instrument is removably coupled to the coupling mechanism. In another embodiment, the coupling mechanism comprises a carriage on which the surgical instrument is slidably mounted. In still another embodiment, the drive unit is coupled to the coupling mechanism via external cabling. In yet another embodiment, the coupling mechanism is mounted over a patient table, and the drive unit is mounted to the patient table. The medical system may optionally comprise a remote controller configured for directing the driver to control the movement of the surgical instrument within the degree(s)-of-freedom. The remote controller may have a user interface for receiving commands from a user. In this case, movements made at the user interface may correspond to movements of the surgical instrument. The remote controller may be coupled to the drive unit via external cabling.  
         [0007]     The drape assembly may have various features. For example, the medical system may further comprise another coupling mechanism coupled directly to the drive unit, in which case, the sterile drape may further cover the other coupling mechanism. The coupling mechanism may have a driver element configured to be actuated by the drive unit, the surgical instrument may have a driven element configured to be actuated by the driver element to move the surgical instrument within the degree(s)-of-freedom, and the drape assembly may have a coupling element mounted within the drape insert that mechanically couples the driver element to the driven element. In this case, each of the driver element, driven element, and coupling element may be configured for rotating to move the surgical instrument within the degree(s)-of-freedom. The medical system may further comprise an instrument adapter in which the surgical instrument member is mounted, and the coupling mechanism may be coupled to the adapter through the drape insert. In this case, the surgical instrument may be removably received by the adapter. The coupling mechanism may have a first driver element configured for being actuated by the drive unit, the adapter may have a second driver element configured for being actuating by the first driver element, the surgical instrument may have a driven element configured for being actuated by the second driver element to move the surgical instrument within the degree(s)-of-freedom, and the drape insert may have a coupling element that mechanically couples the first driver element to the second driver element.  
         [0008]     In accordance with a second aspect of the present inventions, an integrated drape assembly for a medical system is provided. The drape assembly comprises a drape insert and a coupling element mounted within the drape insert. The coupling element is configured to couple a driver element of the medical system to a driven element of the medical system. The drape assembly further comprises a sterile drape extending from the drape insert. The sterile drape is configured for covering at least a portion of the medical system. In one embodiment, the drape insert may be composed of a stiff material. In another embodiment, the coupling element is rotatably mounted within the drape insert. In still another embodiment, the drape insert has a hole, and the coupling element has first and second portions mounted to the drape insert on opposite sides of the hole. In yet another embodiment, the coupling element has a slot configured for receiving a blade of the driver element or the driven element. 
     
    
     BRIEF DESCRIPTION OF THE INVENTION  
       [0009]     The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.  
         [0010]      FIG. 1  is a perspective view of a telerobotic surgical system in accordance with the invention.  
         [0011]      FIG. 2  is a close-up view of a slider and drive mechanism of the system of  FIG. 1 .  
         [0012]      FIG. 3  is close-up view of the slider mechanism of  FIG. 2 .  
         [0013]      FIG. 4  is a cross-sectional view of the slider mechanism taken along the line  4 - 4  of  FIG. 3  with a support clamp attached to the slider.  
         [0014]      FIG. 5  is a cross-sectional view of an angle drive mechanism taken along the line  5 - 5  of  FIG. 4 .  
         [0015]      FIG. 6  is a perspective view of the angle drive mechanism of  FIG. 5 .  
         [0016]      FIG. 7  is cross-sectional view of a linear drive mechanism taken along the line  7 - 7  of  FIG. 4 .  
         [0017]      FIG. 8  is a cross-sectional view of a block and tackle assembly taken along the line  8 - 8  of  FIG. 4 .  
         [0018]      FIG. 9A  is a perspective view of the block and tackle assembly of  FIG. 8 .  
         [0019]      FIGS. 9B-9E  illustrate a sequence of steps for operating the block and tackle assembly of  FIG. 8 .  
         [0020]      FIG. 10  is a cross-sectional view of a split drive shaft taken along the line  10 - 10  of  FIG. 4 .  
         [0021]      FIG. 11  is a cross-sectional view of a cable drive for an outer guide tube taken along the line  11 - 11  of  FIG. 4 .  
         [0022]      FIG. 12  is a fragmentary cross-sectional view of a drive shaft lockout mechanism taken along the line  12 - 12  of  FIG. 10 .  
         [0023]      FIG. 13  is a cross-sectional view of a lockout disk mechanism taken along the line  13 - 13  of  FIG. 12 .  
         [0024]      FIG. 14  is a cross-sectional view of an instrument insert and drive mechanism taken along the line  14 - 14  of  FIG. 4 .  
         [0025]      FIG. 15  is a perspective view of an insert drive cabling of  FIG. 14 .  
         [0026]      FIG. 16A  is an exploded view of a partially disassembled slider unit.  
         [0027]      FIG. 16B  is an exploded view of the instrument adapter and clamshell ready to receive a tool insert.  
         [0028]      FIG. 16C  is an exploded view of the instrument adapter and clamshell with the tool insert mostly inserted into the guide shaft.  
         [0029]      FIG. 16D  is a cross-sectional view taken along the line  16 D- 1   6 D of  FIG. 16C .  
         [0030]      FIG. 16E  is an exploded view of the instrument adapter and clamshell with the tool insert fully inserted into the guide shaft prior to closing the clamshell.  
         [0031]      FIG. 17  is an exploded view of the underside of the instrument insert.  
         [0032]      FIG. 18  is a detail view of a tensioning blade before engagement. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     A description of preferred embodiments of the invention follows.  
         [0034]     The surgical robotic system of the present invention, illustrated generally at  10  in  FIG. 1 , although preferably used to perform minimally invasive surgery, can also be used to perform other procedures as well, such as open or endoscopic surgical procedures. Certain details of the operation of the system  10  are described in U.S. application Ser. No. 10/014,143 filed Nov. 16, 2001, by Brock and Lee, the entire contents of which are incorporated herein by reference.  
         [0035]     The surgical instrument system  10  includes two main components, a master station M and a slave station S. At the master station M, a surgeon  12  manipulates an input device  13  to direct the operation of a surgical instrument  14  of the slave station S to perform a medical procedure on a patient P lying on an operating table T. Although there are shown two surgical instruments  14  positioned on either side of an endoscope  15  and controlled by a respective input device  13 , the surgical system  10  can be used with a single surgical instrument. Moreover, although reference is made herein to a “surgical instrument,” it is contemplated that the principles of this invention also apply to other medical instruments, not necessarily for surgery, and including, but not limited to, such other implements as catheters, as well as diagnostic and therapeutic instruments and implements.  
         [0036]     The surgeon is illustrated as seated in a comfortable chair  16 , and the forearms of the surgeon are typically resting upon an armrest  18  of a master assembly  20  associated with the master station M. A slave assembly  22 , also referred to as a drive unit, is associated with the slave station S, and is attached to a rail  24  of the table T with a clamp  26 , which can be released such that the drive unit can be optimally positioned. In some implementations, the master station M is positioned away from the slave station S, for example, in another room. The assemblies  20  and  22  are interconnected by a cabling  28  with a controller  30 , which typically has associated with it one or more displays  32   a  for viewing the surgical site, and a display  32   b  for monitoring the system performance of the system  10 , and a keyboard (not shown). A slider mechanism  34 , which carries the medical instrument  14 , is supported by a support arm  38 . The drive unit  22  is tethered to the slider mechanism  34  with a bundle of mechanical drive cables  36 . The support arm  38  is provided with a clamp  40  at one end that clamps to the slider mechanism, and another clamp  42  that clamps the support arm to the rail  24 . This mounting arrangement permits the instrument to remain fixed relative to the patient even if the table is repositioned.  
         [0037]     The master station M may also be referred to as a user interface vis-a-vis the controller  30 . Associated with the controller  30  is a computer that operates in accordance with a computer algorithm, such that the computer translates the commands issued at the user interface into electronic signals transmitted to the drive unit  22  through the cabling  28 . These signals direct the operation of the drive unit  22 , which has motors to transform the electrical signals into mechanical movement of the cables  36  to produce the desired replicated motions of the surgical instrument  14 . In particular, the movement of the handle or hand assembly at the input device  13  is interpreted by the controller  30  to control the movement of the medical instrument  14 . The use of the cables  36  facilitates positioning of the drive unit  22  away from the operation region, for example, from the sterile field.  
         [0038]     In the illustrated embodiment, the surgical instrument  14  includes an instrument insert  56  that supports, at its distal end, a tool  44 , and an adaptor  49 , also referred to as a holder, having a guide tube  46  that receives the instrument insert  56  ( FIG. 2 ). The surgical instrument  14  is coupled to a coupling mechanism, preferable a slider mechanism  34 . In this implementation, the surgical instrument  14  provides a number of independent motions, or degrees-of-freedom, to the tool  44 . The surgical guide  46  is basically a passive mechanical device and may be of relatively simple construction. It is a simple guide tube, curved at its distal end, through which the end effector or tool  44  is inserted. Motion of the guide tube results in a movement of the end effector or tool  44 . The guide tube may be designed in length, diameter, and curvature for particular surgical applications such as abdominal, cardiac, spinal, arthroscopic, sinus, neural, etc. The adaptor  49  provides a means for exchanging the instrument inserts and thus the instrument tools  44 , which may be, for example, forceps, scissors, needle drivers, electrocautery probes etc.  
         [0039]     The endoscope  15  ( FIG. 1 ) includes a camera to remotely view the operation site. The camera may be mounted on the distal end of the instrument insert, or may be positioned away from the site to provide an additional perspective on the surgical operation. In certain situations, as shown, it may be desirable to provide the endoscope through an opening other than the one used by the surgical instrument  14 . The endoscope  15  is connected to the master station M with a cable  17  to allow the surgeon  12  to view the procedure with the monitors  32   a.    
         [0040]     In this regard, three separate incisions are shown in the patient P, two side incisions for accommodating the two surgical instruments  14  and a central incision that accommodates the viewing endoscope. A drape  48  covering the patient is also shown with a single opening  50  through which the surgical guide  46  of the surgical instrument  14  extends into the patient P.  
         [0041]     The cable bundles  36  may terminate at respective connection modules or drive unit couplers  52 , which attach to and may be removed from the drive unit  22 . Further details of the connection modules  52  can be found in the earlier co-pending applications No. PCT/US00/12553 and U.S. application Ser. No. 10/014,143 filed Nov. 16, 2001, the entire contents of which are incorporated herein by reference. Although one cable bundle is shown associated with each of the surgical instruments  14 , it is to be understood that more than one cable bundle can be used. Furthermore, although the drive unit  22  is shown located outside the sterile field, it may be draped with a sterile barrier so that it can be operated within the sterile field.  
         [0042]     To set up the system  10 , the user connects the drive unit couplers  52  to the drive units  22  and places a sterile drape  54  over slider mechanisms  34 , cable bundle  36  and the drive unit couplers  52 . The user then clamps the support arm  38  to the slider mechanism  34  with the clamp  40 , which clamps a knob  51  through the drape  54 . The user attaches the sterile adaptor  49  to the underside of the slider mechanism  34  such that the drape  54  is positioned between the slider mechanism  34  and the adaptor  49 . The user then places a sterile tool insert  56  (see, e.g.,  FIG. 2 ) into the adaptor  49  such that the tool  44  extends past the terminal end of the guide tube  46 , and inserts the tool  44  of the surgical instrument  14  into the patient through the incision or opening.  
         [0043]     Particular details of the system  10  and its operation are now described below with reference to  FIGS. 2-18 .  
         [0044]     Turning to  FIG. 2 , the surgical instrument  14  is coupled to a carriage  58  of the slider mechanism  34  with the insert adaptor  49  through a sterile drape insert  62 . The sterile drape insert  62  is attached to the drape  54  in a manner to create a sterile field outside of the drape  54 . The drape  54  is typically made of a suitable flexible material, while the drape insert  62  is made of metal or a stiff plastic. The drive unit  22  includes a set of motors (seven total) with capstans  22   a  that engage with respective drivers  52   a  of the drive coupler  52 .  
         [0045]      FIG. 2  also shows how the slider mechanism  34  is connected to the drive coupler  52  with the single bundle of cables  36 . In particular, the control wires or cables of the bundle  36  connect to the slider mechanism  34  at a single location  36   a  that does not move. That is, although the cables within the bundle  36  weave through the slider mechanism  34 , and are coupled to respective driven capstans or drive pulleys, the point of attachment  36   a  to the slider mechanism  34  is stationary. Hence, none of the cables interferes with the movement of the slider mechanism and thus the surgical instrument and vice versa. It is not necessary for the bundle  36  to be composed of cables. Any suitable flexible segment or tendon can be used in place of one or more of the cables in the bundle  36 .  
         [0046]     Referring also to  FIG. 3 , the carriage  58  includes a block and tackle assembly  64  that decouples the movements of the guide tube  46  and the tool  44  from the overall linear (B-B) and angular (A-A) movements of the slider mechanism  34 . Thus, as the surgeon  12  manipulates the input device  13  ( FIG. 1 ), the computer system  30  issues commands to the drive motor array  22  to produce a desired motion of the instrument  14 . In the illustrated embodiment, the surgical instrument  14  is able to move with seven degrees-of-freedom: the pivoting base motion A-A of the slider mechanism  34 , and thus the carriage  58 , the linear motion B-B of the carriage  58 , a rotary motion C-C of the outer guide tube  46 , a rotary motion D-D of the tool insert  56 , a pitch E-E motion and a yaw F-F motion of the tool  44 , and a grasping motion G-G of a pair of graspers  198  of the tool  44 . Each movement is driven from a respective motor capstan  22   a  of the drive unit or array  22  through push/pull wires or cables of the bundle of cables  36  coupled to the slider mechanism  34 .  
         [0047]      FIG. 3  also illustrates details of the clamp  40  which includes a handle  41 , a moveable jaw  43 , and a stationary jaw  45 , all mounted in a housing  47 . The handle  41  and the jaw  43  function as a cam action lock so that as someone pushes the handle  41  down towards the housing  47 , the moveable jaw  47  and the stationary jaw  45  lock onto the knob  51  at the top of the slider mechanism  34  to secure the slider mechanism  34  to the support arm  38 .  
         [0048]     Turning now to  FIGS. 4-6 , there is shown the carriage  58  supported by a pair of rails  72  attached at one end to an end block  74 , and at the other end to a rotatable base  76 . The rotatable base  76  is connected to an axle  78  which in turn is mounted to an end cap  80  and a housing  90  with a pair of bearings  83 . The end cap  80  is suspended from the housing  90  by a set of bars  92 . An angle drive mechanism  70  includes a pair of gear reduction pulleys  84  and  86  connected to another axle  88  mounted with a pair of bearings  89  to the housing  90 . The drive mechanism  70  also includes a driven pulley  94  secured to the axle  78 , and coupled to the gear reduction pulley  86  with a cable  96 . As shown in  FIG. 5 , the cable  96  has two ends  97  that attach to a cable tensioning block  99  mounted in the driven pulley  94 . Thus, as a set screw  99   a  is turned, thereby moving the block  99 , the appropriate tension is applied to the cable  96 . A pair of cable segments  102  and  104  of the bundle of cables  36  are guided through a pair of guide pulleys  98  and  100  and attach to the gear reduction pulley  84  with respective cable anchors  106  and  108 . The other ends of the cables  102  and  104  are coupled to respective motor capstans  22   a  of the drive unit  22  through the drive coupler  52 .  
         [0049]     Accordingly, as a motor of the drive unit  22  applies tension to either of the cables  102  or  104 , a rotary motion is imparted to the pulley  84  and hence the pulley  86  about the longitudinal axis  110  of the axle  88 . The rotary motion of the pulley  86  consequently imparts a rotary motion through the cable  96  to the driven pulley  94  about the longitudinal axis  112  of the axle  78 . The driven pulley  94  in turn imparts a rotary motion of the rotatable base  76  and thus the carriage  58  back and forth in the direction of the double arrow A-A. Referring to  FIG. 7 , there is shown a linear drive mechanism  120  that moves the carriage  58  back and forth along the rails  72  in the direction B-B. The linear drive mechanism  120  includes a pair of cable segments  122  and  124  attached to the carriage with respective anchors  126  and  128 . The cable  122  is guided about a guide pulley  130 , while the cable  124  is guided through a guide pulley  132 , the guide pulley  130 , and about an idler pulley  134  mounted in the end block  74 . The other ends of the cables  122  and  124  are attached to a motor of the drive unit  22  through the coupler  52 . Accordingly, as tension is applied to the cable  122 , the carriage moves from left to right, while tension applied to the cable  124  moves the carriage  58  from right to left.  
         [0050]     Turning now to  FIG. 8 , there is shown details of the block and tackle assembly  64 . The block and tackle assembly  64  includes a coupling system  200  for each of the degrees-of-freedom C-C, D-D, E-E, F-F, and G-G ( FIG. 3 ) that are decoupled from the linear B-B and rotary movements A-A of the carriage  58 . Although the coupling systems  200  are layered or stacked, the operation of the systems is best illustrated with reference to the single coupling system shown in  FIG. 8  and further illustrated in  FIGS. 9A-9E . The coupling system  200  includes two stationary pulleys  202  and  204  fixed to the slider  58 , and two additional pulleys  206  and  208  mounted in respective sliders  206   a  and  208   a  that are able to slide relative to the carriage  58  along tracks  210 . The pulleys  202 ,  204 ,  206 , and  208  and the sliders  206   a  and  206   b  are made of plastic or metal, and the tracks  210  are formed of plastic or Teflon.™. or any other suitable material that minimizes friction between the tracks  210  and the sliders  206   a  and  206   b . A pair of cable segments  220  and  222  are attached at a first location  214  and a second location  216 , respectively, to a pair of anchors  218  on the end block  74 . The first cable segment  220  wraps around the sliding pulleys  206  and the stationary pulley  202 , and the second cable segment  222  wraps around the other sliding pulley  208  and the other stationary pulley  204 . The two segments  220  and  222  are fed through a pair of guide pulleys  224  and  226  and are coupled to a respective motor of the array  22  through the coupler  52 . The sliding pulleys  206  and  208  are also connected with another cable  230  to a driven capstan  232  that imparts one of the degrees-of-freedom of movement C-C, D-D, E-E, F-F, and G-G ( FIG. 3 ) to the surgical instrument.  
         [0051]     When the system  10  is in operation, as the carriage  58  moves back and forth with the linear motion B-B ( FIG. 9E ), the cable segments  220  and  222  roll freely over the pulleys  202 ,  204 ,  206 , and  208  without rotating the driven capstan  232 . That is, the linear movement of the carriage  58  does not influence, and is therefore decoupled from, the degrees-of-freedom of movement C-C, D-D, E-E, F-F, and G-G.  
         [0052]     If, however, the capstan  22   a  is rotated to pull on the segment  220  or segment  222 , the distance between one of the stationary pulleys  202  or  204  and the corresponding sliding pulley  206  or  208  decreases, while the distance between the other fixed and sliding pulleys increases, resulting in a rotary motion of the driven capstan  232 . By way of example, as shown in  FIG. 9C , if the capstan  22   a  is rotated counterclockwise in the direction R to pull on the cable segment  222  from an initial position shown in  FIG. 9B , the length of the cable  222  around the pulleys to the anchor  218  is shortened, causing the sliding pulley  208  to move towards the stationary pulley  204 . Since the cable  230  is of a fixed length, it pulls the other sliding pulley  206  away from the stationary pulley  202 , and rotates the driven capstan  232  counterclockwise with a rotary movement R′. No linear movement is imparted to the carriage  58 .  
         [0053]     Similarly, as shown in  FIG. 9D , if the capstan  22   a  is rotated clockwise in the direction R″ to pull on the cable segment  220 , the sliding pulley  206  moves towards the stationary pulley  202 , while the sliding pulley  208  moves away the stationary pulley  204 , which imparts a clockwise rotary motion R″′ to the driven capstan  232 .  
         [0054]     Note, as mentioned earlier, the movements B-B, C-C, D-D, E-E, F-F, and G-G do not influence and are therefore decoupled from the rotary movement A-A of the carriage  58 .  
         [0055]     Referring now to  FIG. 10 , a drive mechanism  300  used to drive one of the degrees-of-freedom E-E, F-F, or G-G of the tool  44  is shown. The drive mechanism  300  includes a lower drive shaft  302  mounted in the adapter  49 . The lower drive shaft  302  is coupled to an upper drive shaft  304  of the coupling system  200  through a rotatable coupler  306  that is mounted in the drape insert  62 . The lower drive shaft  302  is also coupled to a respective drive wheel  308  of the instrument insert  56 . The upper drive shaft  304  is provided with a set screw  310  that when rotated pushes against a set screw extension  312  which clamps the cable  230  in the driven capstan  232  mounted about the upper drive shaft  304 . As such, as the driven capstan  232  rotates, as discussed with reference to  FIGS. 9A-9E , the rotary motion of the capstan  232  imparts a rotary motion of the drive wheel  308  through drive shaft  304 , coupler  306 , and the lower drive shaft  302 .  
         [0056]     As mentioned above, the insert can be made of a stiff plastic. Similarly, the coupler  306  can be made from two plastic pieces  306   a  and  306   b  ( FIG. 10 ) connected together through a hole in the base  63  of the insert  62 . The lower piece  306   b  is provided with a bearing  307  that allows the coupler  306  to rotate relative to the base  63 . Either or both of the insert  62  and the coupler  306  can be made of metal rather than plastic.  
         [0057]     Rotary motion of the guide tube  46  (C-C) and the insert  56  (D-D) are imparted though somewhat different mechanisms. In particular, referring to  FIG. 11 , a drive mechanism  330  used to drive the rotary motion of the outer guide tube  46  includes a lower drive shaft  332  mounted in the adapter  49 . The lower drive shaft  332  is coupled to a respective upper drive shaft  304  through the coupler  306 , similar to that described above for the lower drive shaft  302 . However, unlike the previously described drive mechanisms  300 , the lower drive shaft  332  is provided with a right angle cable drive  333 . The cable drive  333  includes a pulley  334 , and a pair of idler pulleys  336  mounted to the adapter  49  with a shaft  338  and positioned at 90.degree. from the pulley  334 . A cable  340  is wrapped around the pulley  334 , guided through the idler pulleys  336 , and attached to an outer tube drive pulley  342  clamped to the outer guide tube  46  with a clamp screw  344 . Hence rotary motion of the upper drive shaft  304  about an axis  346  ( FIG. 4 ) results in a rotary motion (C-C) about an axis aligned at a 90.degree. angle from the axis  346 .  
         [0058]     Referring back to  FIG. 4 , a similar drive mechanism  350  is used to rotate the shaft  353  of the insert  56  in the direction D-D ( FIG. 3 ). For the drive mechanism  350 , a drive cable  352  is coupled to tool shaft drive pulley  354 . The drive pulley  354  in turn is coupled to the shaft  353 . As such, as the upper drive shaft  304  rotates about an axis  360 , a consequent rotary motion is imparted to the shaft  353  to produce the rotary motion D-D.  
         [0059]     Referring to  FIGS. 12 and 13 , when the adaptor  49  is clamped to the drape insert  62 , a blade like tip  414  of the adaptor  49  fits in a slot  416  of the coupling  306 , so that rotation of the coupling  306  rotates the lower drive shaft  302  or  332 . When removing the adaptor  49 , a lockout mechanism  400  assures that the blade  414  remains in the same position to fit into the slot  416  when the adaptor  49  is reattached to the insert  62 . That is, the lockout mechanism  400  prevents rotation of the lower drive shafts  302  or  332  when the insert adapter  49  and the drape insert  62  are not clamped together. The lower drive shaft  302  or  332  is provided with a washer  404  positioned beneath a disk  406 . A clip  408  secures the washer  404 , disk  406  and hence the lower drive shaft  302  in place. When the adapter  49  and the insert  62  are clamped together, a protrusion  410  on a flexure  412 , attached to the surface the adaptor  49  with a screw  413 , is pushed down by the drape insert  62  to release a catch tab  411  on the flexure  412  from engagement with the disk  406 , thereby allowing the drive shaft to rotate. That is, the catch tab  411  is pushed out of a respective perforation or hole  406   a  of the disk  406 . Meanwhile coupling between the lower drive shaft  302  and the coupler  306  occurs as the blade  414  engages with the slot  416  of the coupling  306 .  
         [0060]     Additional details of the arrangement of the outer tube drive pulley  342  and the shaft drive pulley  354  in relation to the insert  56  are shown in  FIG. 14 . The outer tube drive pulley  342  is positioned between an end section  500  and a mid section  502  of the adapter  49 . As mentioned above the outer tube drive pulley  342  is clamped to the outer tube  46 , which is mounted in the end section  500  and the mid section  502  with respective bearings  504  and  506 . Hence rotation of the drive pulley  342  causes a consequent rotation of the guide tube  46  with the degree-of-freedom of movement C-C ( FIG. 3 ). The shaft drive pulley  354  is positioned adjacent to the mid section  502  and mounted about the outer tube  46  with a bearing  508  so that it can rotate relative to the outer tube  46 . A retainer clip  510  holds the drive shaft pulley  354  in place. The shaft pulley  354  is also provided with a valve  356 , made from, for example, silicone. The shaft  353  is inserted through a flexible flap  356   a  with a hole in it and into the guide tube  46 . Prior to the insertion of the shaft  353  into the guide tube  46 , the resiliency of the valve  356  and in particular the flap  356   a  causes the hole in the flap to close off, hence, creating a seal between the guide tube  46  and the remainder of the adaptor  49  to prevent gas from escaping from the operating site through the guide tube  46 . Similarly, when the shaft  353  is in place, the flap  356   a  forms a seal about the shaft  353  to prevent the escape of gas. A drive arm  512  of the insert  56  engages with a slot  514  of the pulley  354  to couple the shaft  353  with the pulley  354  so that the shaft  353  rotates with the pulley  354  with the degree-of-freedom of movement D-D ( FIG. 3 ).  
         [0061]     Referring now to  FIG. 15 , there is illustrated how the drive wheels  308  of the insert  56  engage with respective lower drive shafts  302 . In particular, a face  520  of each drive wheel  308  mates with an opposing face  522  of the respective lower drive shaft  302 .  
         [0062]     Referring now to  FIG. 16A , as well as  FIGS. 2 and 4 , details of the attachment of the adaptor  49  to the slider mechanism  34  are shown, as well as the insert  56  prior to insertion of the shaft  353  into the guide tube  46 . The drape  54  is placed between the adaptor  49  and the bottom of the carriage  58 , and then a lip  600  of the adaptor  49  is placed into a corresponding lip  602  of the carriage assembly  58 , with the drape  54  pinched between the two lips. The adaptor  49  is then rotated up so that it engages with the carriage  58  through the drape insert  62 . A clamp  604  is then snapped in place to secure the adaptor  49  to the slider mechanism  34 .  
         [0063]     Referring to  FIG. 16B , there is shown the insert  56  prior to insertion into the adaptor  49 . The adaptor  49  includes alignment holes  610  for the corresponding nubs  612  of the insert  56 . The adaptor  49  also includes a clamshell  614  attached to a base portion  616  with a pivot joint  618 . The clamshell  614  is provided with a pair of pins  617  that engage with respective keyholes  620  of a catchplate  622 . A clamshell release handle  624  is springloaded with a spring  625  ( FIG. 10 ) to allow a user to release the clamshell  614  from the catchplate  622  by pushing on the handle  624 .  
         [0064]     Referring also to  FIG. 16C , after the shaft  353  is inserted into the guide tube  46 , the drive arm  512  mates with the receiving slot  514  to couple the shaft  353  to the shaft drive pulley  354 . In addition, a release pin  626  extending from the base portion  616  pushes against a flexure  628  to unlock the shaft  353  ( FIG. 16B ). Referring also to  FIG. 17 , the flexure  628  has a hole  629  in which a tab  631  is positioned before insertion. The tab  631  is attached to the shaft  353  such that as the flexure  628  is pushed away from the tab  631  the shaft  353  is free to rotate.  
         [0065]     Referring also to  FIG. 16D , as the insert  56  is rotated in place, the nubs  612  align and fit into the alignment holes  610  while the face  520  of the drive wheels  308  mate with the face  522  of the lower drive shafts  302 . The clamshell  614  is provided with a spring  630  ( FIGS. 10 and 16 C) that pushes against the bottom of the insert  56  when the clamshell  614  is snapped into the locked position so that the insert  56  abuts against the adaptor  49  with an applied force.  FIG. 16E  illustrates the instrument insert  56  fully inserted, but with the clamshell  614  still open.  
         [0066]     The adaptor  49 , such as depicted in  FIG. 16A , is readily attachable and detachable with the coupling mechanism such as the block and tackle assembly  64 . This provides a more adaptable surgical system useable with a greater number of types of surgical procedures. For example, one of the primary differences from adaptor-to-adaptor may be the radius of curvature of the distal curved end of the guide tube  46 . Also, the length of the curved section of the guide tube may be varied, or the combination of curvature and length can to taken into account in selecting different adaptors. Moreover, the diameter of the tube could be different depending upon size and diameter of the instrument insert. Furthermore, instead of providing a curvature at the distal end of the guide tube, there can be a straight bend at the distal end. Either a curvature, bend, or other deflection of the distal end of the guide tube provides the desired off-set of the distal end so that, upon rotary motion C-C of the guide tube, there is motion of the tool out of the plane defined by the pivoting base motion A-A.  
         [0067]     For some surgical procedure, as mentioned above, it may be desirable to substitute different types of adaptors. For example, if a particular procedure requires work in both a focused small area, as well as in a broader extending area of the patient, it is desirable to use different types of adaptors. The different adaptors might have different lengths, diameters, curvatures, or combinations thereof.  
         [0068]     Details of the individual drive mechanisms of the insert  56  that provide the degrees of freedom of movement E-E, F-F, and G-G ( FIG. 3 ) are illustrated in  FIGS. 17 and 18 , as well as  FIG. 15 . For each degree-of-freedom, a pair of cables  700  and  702  extends through the shaft  353  and is coupled at the terminal ends of the cables to the tool  44 . The other ends of the cables  700  and  702  are attached to respective drive wheels  308  with cable anchors  704  and  706 .  
         [0069]     Illustrated in  FIG. 18  is a tensioning mechanism  710  that is in a non-tensioned position when the insert  56  is not in use. The tensioning mechanism includes a tensioning handle  712  ( FIG. 17 ) provided with a tab  729  on its underside that engages with a slot  731  on the bottom of a blade  714 , and a pair of outer lips  730  that engage with a pair of undercuts  732  on the bottom of the insert housing  750 .  
         [0070]     Prior to inserting the insert  56  into the adaptor  49 , a user turns the handle  712  about 90.degree. until the tension blade  714  rests against a stop pin  716 , while a pair of spring-arm catches  734  snap up and latch the blade  714  in place. When this occurs, the blade  714  spreads the cables  700  and  702  apart such that they are pushed against a pair of cable guide posts  718  to pretension the cables  700  and  702 . This pretension position of the blade  714  is shown in  FIGS. 14 and 15 . The handle  712  is provided with a pair of slots  730   a  that match up with the undercuts  732  so that when the handle has been turned approximately 90.degree. the handle can be removed from the insert  56 . Note also that the housing  750  has a cutout  752  that provides a clearance while the insert  56  is being inserted into the adaptor  49 .  
         [0071]     The blade  714  can be made of plastic and is provided with smooth surfaces  720  made of, for example, stainless steel, so that the cables  700  and  702  are able to glide over the blade  714  with minimal friction. Similarly, the guide posts  718  are also provided with smooth surfaces  722  that minimize friction between the posts  718  and the cables  700  and  702 .  
         [0072]     While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For example, although the slider mechanism is described in the context of a coupling mechanism, other embodiments in which the cable bundle is attached at its distal end at a stationary location are also considered within the scope of the present invention.