Patent Publication Number: US-2011066173-A1

Title: Procedural cannula and support system for surgical procedures

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 11/789,318, filed Apr. 24, 2007, now U.S. Pat. No. 7,883,156, which claims the benefit of U.S. Provisional Application No. 60/794,563, filed Apr. 24, 2006, U.S. Provisional Application No. 60/801,113, filed May 17, 2006, U.S. Provisional Application No. 60/801,034, May 17, 2006, and U.S. Provisional Application No. 60/819,235, filed Jul. 7, 2006. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of devices and procedures for use in performing surgery in the peritoneal cavity using access through a natural orifice. 
     BACKGROUND OF THE INVENTION 
     Surgery in the abdominal cavity is typically performed using open surgical techniques or laparoscopic procedures. Each of these procedures requires incisions through the skin and underlying muscle and peritoneal tissue, and thus results in the potential for post-surgical scarring and/or hernias. 
     Systems and techniques in which access to the abdominal cavity is gained through a natural orifice are advantageous in that incisions through the skin and underlying muscle and peritoneal tissue may be avoided. Use of such systems can provide access to the peritoneal cavity using an access device inserted into the esophagus, stomach or intestine (via, for example, the mouth or rectum). Instruments are then advanced through the access device into the peritoneal cavity via an incision in the wall of the esophagus, stomach or intestine. Other forms of natural orifice access, such as vaginal access, may similarly be used. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an access cannula anchored in an incision in a stomach for use in a natural orifice procedure. 
         FIG. 2A  is a schematic side view showing the interior of an abdominal cavity, and further showing use of a first embodiment of a procedural cannula and support system. 
         FIG. 2B  is a schematic top view (anterior view) showing the interior of an abdominal cavity and further illustrating use of the procedural cannula and support system of  FIG. 2A . 
         FIG. 3  is a perspective view showing an alternative procedural cannula and support system. 
         FIG. 4  is a perspective view of the spine of the system of  FIG. 3 . 
         FIG. 5A  is a perspective view illustrating two of the spine elements of the spine of  FIG. 4 . 
         FIG. 5B  is a perspective view of an alternative spine element for use in the system of  FIG. 3 . 
         FIG. 6  is a perspective view showing the distal ends of the tool cannulas and linkage of the system of  FIG. 3 . 
         FIG. 7  is a cross-section view taken along the plane designated  7 - 7  in  FIG. 6 . 
         FIGS. 8A and 8B  are a top perspective view and a bottom perspective view, respectively, of a distal end of the system of  FIG. 3  using an additional tool cannula. 
         FIGS. 9 and 10  are perspective views of the system of  FIG. 3  extending from an access cannula and including a retractor extending from a longitudinal tool cannula. 
         FIG. 11A  is a top perspective view showing an alternative linkage assembly in combination with a spine, procedural cannulas, and a central retractor. 
         FIGS. 11B and 11C  are a top plan view and a side elevation view of the linkage assembly of  FIG. 11A . In  FIG. 11C , the center retractor is shown in a downwardly deflected position, and phantom lines are shown to illustrate the retractor in an upwardly deflected position. 
         FIG. 11D  is a top plan view of the linkage assembly of  FIG. 11A  in the streamlined position. 
         FIG. 11E  is a perspective view similar to  FIG. 11E  illustrating exemplary movement patterns for the tool cannulas and associated tools. 
         FIG. 12A  is a perspective view of one embodiment of a user interface for the system of  FIG. 3 . 
         FIG. 12B  is a perspective view of an alternative user interface for the system of  FIG. 3 . 
         FIGS. 13 and 14  are a perspective view and a cross-sectional side view of a gimbal assembly. 
         FIGS. 15A and 15B  are perspective views of the gimbal assembly of  FIG. 13  showing two exemplary locking mechanisms. 
         FIGS. 16A and 16B  are perspective views of an alternative gimbal system. 
         FIG. 17  is a perspective view of a third embodiment of a procedural cannula and support system. 
         FIG. 18  is a detailed perspective view of the proximal end of the system of  FIG. 17 . 
         FIG. 19  shows the gimbal system of the  FIG. 17  embodiment. 
         FIG. 20  is an exploded view of the gimbal system of  FIG. 19 . 
         FIG. 21  is a plan view of the distal surface of the ball of the gimbal system of  FIG. 19 . 
         FIG. 22  is a plan view of the proximal surface of the ball of  FIG. 21 , with the cap removed and shown in perspective view. 
         FIG. 23  is a top view similar to  FIG. 2B  showing the system of  FIGS. 9 and 10  in use for surgery on a liver. 
         FIG. 24  schematically illustrates an abdominal cavity and shows an alternative support system mounted to the interior wall of the abdominal cavity. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Applicant&#39;s prior Provisional Application No. U.S. application Ser. No. 11/528,009, TRANSGASTRIC SURGICAL DEVICES AND PROCEDURES, Filed Sep. 27, 2006 describes various embodiments of surgical access cannulas for use in gaining access to the peritoneal cavity of a patient via a natural orifice. When used for transoral procedures, the distal end of an access cannula  10  ( FIG. 1 ) is advanced orally through the esophagus and into the stomach or intestine. Instruments are passed through the cannula and are used to form an incision in the stomach or intestinal wall, giving access to the peritoneal cavity. The access cannula  10  is anchored in the incision using expandable anchors  12   a ,  12   b  positioned against the inner and outer surfaces of the stomach wall. Insufflation gas may be introduced into the peritoneal cavity via the access cannula to create working space within the cavity. The access cannula may include valves or seals that allow for sealed access through the incision, permitting sterile passage of instruments into the peritoneal cavity without loss of insufflation pressure. The access cannula  10  may be a flexible tube formed of polymeric material (e.g. polyurethane) having an embedded braid. In other embodiments, a more rigid access cannula may be used. The &#39;009 application, which is incorporated herein by reference, describes various additional components of access cannula systems, including anchoring features, elements for forming incisions in an interior body wall such as the stomach, and closure devices. 
     This application describes a procedural cannula and support system ideally used in combination with an access cannula that has been used to gain access to the peritoneal cavity. For example, once access cannula  10  has been passed through the oral cavity and stomach and secured within a stomach wall incision using anchors  12   a ,  12   b , a procedural cannula and support system of the type described herein is passed through the access cannula and into the peritoneal cavity. 
     For certain procedures, it would be advantageous to allow the surgeon to perform a natural orifice surgical procedure in a manner that allows him/her to approach the surgical target within the peritoneal cavity from the same direction from which s/he would typically approach that same structure using a laparoscopic or open surgical procedure. For example, if a particular procedure utilizes an anterior approach to the treatment site when carried out using laparoscopic or surgical techniques, it would also be desirable to allow the surgeon to approach the treatment site from an anterior perspective even when using a natural orifice technique. The system illustrated in the attached drawings allows these same approaches to be used using natural orifice access, thus allowing a surgeon to easily and intuitively transition between natural orifice surgical procedures and open or laparoscopic procedures. 
     In general, the disclosed embodiments include at least one procedural or tool cannula through which instruments are passed to the operative site. A support system provides rigid support for the procedural cannula(s) within the body. 
     Referring to  FIGS. 2A and 2B , one embodiment of a natural orifice surgical system includes an instrument system  22  and a support system  24 . These figures schematically illustrate the peritoneal cavity of a patient with the support system and instrument system extending into the cavity from an incision (not shown) through the stomach wall. In use, the support system  24  forms a sort of scaffold within the body to support the instrument system  22  in a location that allows the surgeon to advance the instruments of the instrument system using a desired approach. Thus, for example, if performing a procedure that typically uses an anterior approach when carried out surgically or laparoscopically, the user might position the support system  24  adjacent the abdominal wall W as shown in  FIG. 2A . 
     Support system  24  includes an elongate shaft or spine  26  that extends from an incision in a body organ such as the stomach S or other hollow organ (e.g. intestine, vagina) from which natural orifice access has been gained as described above. In a preferred embodiment, shaft  26  is disposed within an access cannula  10  which may be of the type shown in  FIG. 1 . Shaft  26  is preferably one capable of being sufficiently flexible for passage through the natural orifice and body organ, and for manipulation within the peritoneal space, but also capable of being placed in a self-supporting rigid state once positioned at a desired location. In one embodiment, shaft  26  is a shaft formed of a plurality of spine elements  28  having tensioning cables that may be placed under tension to stiffen the shaft  26 . As will be discussed in greater detail below, the spine elements are shaped such that the shaft  26  will assume a shape predetermined to give the curvature needed to position the shaft  26  at the desired location. Shaft  26  may include a lumen (not shown) or other features for supporting an endoscope (not shown) oriented towards the treatment site. 
     Instrument system  22  includes one or more procedural cannulas  30   a ,  30   b , each having an opening  152  at or near its distal end. Cannulas  30   a ,  30   b  may include a curved distal portion as shown, and may additionally or alternatively be deflectable in predetermined directions using pullwires, mandrels, or other deflection mechanisms, including those known in the art for deflecting catheters, introducers and guidewires. 
     Instruments  32  (e.g. forceps, endoscopes, suture devices, staplers) are extendable through the procedural cannulas  30   a ,  30   b  and into position at the target site in the peritoneal cavity. As best shown in  FIG. 2B , two procedural cannulas are useful in that they allow for the simultaneous use of two instruments  32 . The procedural cannulas  30   a ,  30   b  may be passed into the peritoneal cavity via the same access cannula  10  ( FIG. 1 ) through which the support shaft  26  extends, or they may be passed through one or more separately placed access cannulas  10 , or, as described in detail in connection with  FIG. 3 , they may be passed through a lumen in the shaft  26 . 
     A coupling  34  couples the instrument system  22  and support system  24 . The coupling  24  may by any type of device that couples the procedural cannulas  30   a ,  30   b  to the shaft  28 . In the  FIG. 2A-2B  embodiment, the coupling takes the form of a linkage  36  that allows the cannulas to be suspended from the shaft  26  and also provides the additional benefit of maintaining the orientation of the cannulas  30   a ,  30   b  relative to one another. The linkage  36 , which is most visible in  FIG. 2B , includes a first mount  38  on the shaft  26 , and second mounts  40   a ,  40   b  on the procedural cannulas  30   a ,  30   b . Linkage bars  42   a ,  42   b  are pivotally coupled to the mount  38  and the mounts  40   a ,  40   b . Second linkage bars  44   a ,  44   b  are pivotally coupled to, the mounts  40   a ,  40   b  and a pivot point  46 . As can be seen in  FIGS. 2A and 2B , the support system  24  positions the procedural cannulas  30   a ,  30   b  so that access to the treatment site can be gained using an approach that is familiar to the practitioner, despite the fact that the instruments are inserted into the body using a drastically different approach. Deflection features of the cannulas  30   a ,  30   b  allow those cannulas to be manipulated so as to position the instruments  32  where they are needed, without requiring that the instruments include specialized features for steering and deflection. The linkage  36  maintains the relative orientation of the cannulas  30   a ,  30   b  towards the treatment site. 
       FIG. 3  shows a second embodiment of a natural orifice surgical system  100 . System  100  includes a locking spine  102  and a pair of tool cannulas  104 . The system  100  is similar to the embodiment of  FIGS. 2A and 2B , but differs in that the tool cannulas  104  pass through a lumen  105  in the shaft of the locking spine  102  of the support system, allowing for a more streamlined system that occupies a reduced amount of space. An endoscope  107  also extends through the spine  102 , allowing the user to observe the procedure being carried out at the distal end of the system. Instruments  32  extend from the tool cannulas to the operative sites. Instruments  32  may include forceps, retractors or any other instruments needed to carry out the desired procedure within the peritoneum. 
     The locking spine  102  is preferably passed into the body through an access cannula  10  as described in connection with  FIG. 1  and as shown in  FIGS. 9 and 10 . 
     Spine  102  is preferably one capable of being sufficiently flexible for manipulation within the peritoneal space, but also capable of being placed in a self-supporting rigid state once positioned at a desired location. In one embodiment, spine  102  is a shaft formed of a plurality of spine elements having tensioning cables that may be placed under tension to stiffen the shaft. The spine elements are shaped such that the spine will assume a shape predetermined to give the curvature needed to position the distal end of the spine at the desired location and oriented towards the treatment site. 
     A detailed view of the locking spine  102  is shown in  FIG. 4 . Referring to  FIG. 4 , locking spine  102  is formed of a plurality of spine segments  106   a ,  106   b  threaded over a pair of cables (not shown in  FIG. 4 ) to form a flexible shaft. Each cable is coupled to a locking handle  108  that is moveable to the locked position shown in  FIG. 4  to apply tension to the cables and to thereby rigidize the spine  102 . To release the spine to a flexible state, the handles are moved in the direction of arrows A. 
     A plurality of the spine segments  106   a  are cylindrical segments having end faces that are perpendicular to the axis of the cylindrical segments. When a plurality of these cylindrical segments  106   a  is strung over the cables, they form a relatively straight spine section  110  when the handles  108  are locked. Others of the spine segments  106   b  have angular end faces and are assembled such that the chosen combination of angled segments  106   b  will give the distal portion  112  of the spine  102  a predetermined bend configuration when the spine  102  is locked as shown in  FIG. 4 . 
       FIG. 5A  is a perspective view showing a pair of angled spine segments  106   b  assembled together. Each spine segment includes a central through hole  114  and a plurality of side through holes  116  surrounding the central through hole  114 . Similar hole patterns may also be included in the cylindrical segments  106   a  that form the straight section of the spine. A variety of angled spine segments with end faces of different angles make up the curved distal portion of the spine. A group of spine segments with a predetermined combination of angles are selected to produce an overall shape for the spine that will support the associated tools in an optimal position for the procedure to be carried out within the body. In the  FIG. 4  embodiment, spine segments are combined to create a multi-dimensional bend as shown. 
     The spine segments  106   a ,  106   b  etc. are “strung” onto cables  118  by passing each of the cables through one of the side through holes  116  in each of the spine segments. The side hole that is to receive the cable  118  for a particular spine segment  106   b  is selected based on the orientation in which the angled face of that segment must be placed to give the spine  102  the correct curve at that particular location on the spine  102 . Thus, manufacturing instructions might list out a sequence of angled segments, giving for each segment the face angle that is to be used, as well as a designation of which side holes  116  are to receive each cable for that particular segment. An exemplary entry on the list might read “segment #10, angle 15°, cable #1 through hole A, cable #2 through hole D”. 
     The central through holes  114  of the spine segments  106   a ,  106   b  align to form the lumen  105  ( FIG. 4 ) of the spine  102 . 
       FIG. 5B  shows an alternative spine segment  106   c  having a concave end face  103   a  and a concave end face  103   b , each of which comes together in a nesting relationship with adjacently placed spine segments. Slots  113  may be provided the concave face  103   a  for receiving corresponding mating ribs (not shown) on the convex face, allowing the segments to “key” together when assembled to minimize rotational movement of segments relative to one another. 
     In the  FIG. 5B  embodiment, the central through hole  114   c  includes a plurality of lobes  115   a ,  115   b ,  115   c  each sized and positioned such that one or more instruments passed through the through hole  114   c  can seat in a corresponding one of the lobes. This helps to maintain the instruments in a stable position within the elongate lumen of the spine formed by the assembly of the segments  106   c . In this embodiment, the holes  116   c  through which the cables (not shown) are threaded are positioned in pairs as shown, although alternate patterns will be equally suitable. 
       FIG. 6  is a perspective view of the distal end of the system  100  of  FIG. 3 , showing the distal ends of the tool cannulas  104 . As with the first embodiment, the system  100  includes features that work in combination with the spine  102  to support and orient the tool cannulas  104  as appropriate for a given procedure. A linkage  120  is pivotally connected to the cannulas  104  at pivot points  122  and couples the cannulas  104  to the supporting spine  102 . Linkage  120  also provides structural support for the distal portions of the tool cannulas  104  and maintains the relative orientation of the cannulas  104 . As with the first embodiment and as shown in  FIG. 3 , the linkage  120  is attached to a pivot mount  124  on the distal portion of the locking spine  102 . Another of the pivot mounts  125  is coupled to a pull wire  127  that extends proximally through spine  102  to a location outside the body. In an alternative embodiment shown in  FIGS. 8A and 8B , pivot mount  125  may be coupled to the distal portion of a third longitudinal tool cannula  104   a  extending longitudinally from the spine  102 , or to a similarly positioned tool shaft. As another alternative, either or both of the pivot mounts  124 ,  125  may extend into free space as shown in  FIGS. 9 and 10  instead of being attached to the cannula  104   a  and/or spine  102 . 
     The linkage  120  is positionable in a collapsed streamlined position in which tool cannulas  104  are near the longitudinal axis of the spine  102  for passage through the access cannula  10 . Dashed lines in  FIG. 6  show the arrangement of the linkage  120  and pivot mounts  122  when in the collapsed position. When in the streamlined position, the pivot mounts  122  are positioned side by side, thus orienting the tool cannulas  104  adjacent to one another. When in the deployed position, the pivot mounts are positioned approximately 3-7 inches apart, and more preferably approximately 4-6 inches apart. 
     Opening the linkage positions the cannulas  104  as shown in  FIGS. 3 ,  6  and  8 A- 10  and thus points the instruments  32  positioned in the cannulas  104  generally towards an operative site. The linkage  120  of  FIG. 6  may be deployed to the open position by withdrawing pullwire  127 , whereas the  FIGS. 8A ,  8 B embodiment can be deployed by advancing the distal end of the longitudinal tool cannula  104   a  in a distal direction to move the linkage  102  out of the access cannula and/or to deploy the linkage to the expanded position. In other embodiments, one or more of the pivot points  122 ,  124 ,  125  may be spring loaded to facilitate expansion of the linkage  120 . Any combination of these deployment mechanisms, or others not specifically mentioned, may instead be used to deploy the linkage  120  in the peritoneal cavity. 
     In another alternative shown in  FIGS. 11A-11C , linkage  120   a  includes a pair of members  130 . Each member  130  is attached by a corresponding one of the tool cannulas  104  by a first hinge  132  and to a central retractor  104   b  (or, alternatively, to a longitudinal tool cannula like cannula  104   a  of  FIG. 8A ) by a second hinge  134 . Hinges  132  may be mounted to corresponding collars  136  on the tool cannulas  104 , and hinge  134  may be on a similar collar  138  ( FIG. 11B ) on retractor  104   b . When linkage  120   a  is in the collapsed position, members  130  extend in a distal direction as shown in  FIG. 11D . To deploy the linkage  120   a , central retractor  104   b  is withdrawn proximally, causing the members  130  to pivot at hinges  132 ,  134 . 
     Referring to  FIG. 11C , central retractor  104   b  includes a proximal section  140  and a distal section  142 . Proximal section  140  is formed of a number of segments  144  strung onto one or more cables, with shorter segments  146  and an instrument tip  147  on the distal section  142 . Cables within the retractor  104   b  are arranged such that the retractor becomes rigid when the cables are tensioned, and such that distal section  142  will deflect when the balance of tension within the cables is altered using controls outside the body. For example, retractor  104   b  may be deflectable towards and away from the body tissue as shown in  FIG. 11C  to allow tissue to be lifted by the retractor so the tissue may be acted upon by an instrument carried by one of the tool cannulas  104 . Additional pull cables (not shown) are operable to open and close the jaws of the retractor tip  147 . 
     In the disclosed embodiments, each tool cannula  104  preferably has a pre-shaped curve in its distal region. The curve orients the cannula  104  such that when the linkage is opened, instruments  32  ( FIGS. 10A ,  10 B) passed through the central lumens  126  of the cannulas  104  can access a common treatment site. The preformed shape may be set using any of a number of methods. For example, the shaped region may have a segmented construction similar to the segmented spine  102 , with the individual segments shaped to give the tool cannulas a shape that will orient the cannulas as shown in  FIGS. 3 ,  9  and  10  when the cables running through the segments are tensioned. With this design, the entire length of the cannula may be segmented, or the distal portion may be formed of polymer tubing to allow flexibility. Alternatively, cannulas  104  can be made of pre-curved tubing having rigidity sufficient to prevent buckling during use. Reinforcing braid made of stainless steel or other materials may be formed into the walls of the tubing in the rigid section of the cannulas  104 . 
     As with the  FIG. 2A-2B  embodiment, the distal end of each tool cannula  104  further includes a region that is deflectable in multiple directions to allow positioning and manipulation of the operative ends of the instruments. This avoids the need for sophisticated steerable surgical instruments. Instead, instruments  32  ( FIG. 10 ) having flexible shafts are positioned in the tool cannulas  104 , and steering of the instruments is achieved by deflecting the tool cannulas  104 . Because the tools  32  are flexible, it may be necessary to “stiffen” the shaft of the tool  32  to allow the tool to be successfully used. A slideable stiffening cannula  33  ( FIG. 10 ) may be advanced from within the tool cannula  104  over a portion of the shaft of the tool  32  to effectively stiffen the tool&#39;s shaft during the procedure, thus allowing the tool to be pressed into contact with body tissue without buckling. Other internal structures such as stiffening mandrels, reinforcing collars or braids, may instead be used for this purpose. 
     In a preferred embodiment, deflection of the tool cannulas  104  is performed using a pullwire system. Referring to  FIG. 7 , pullwires  128  extend through corresponding pullwire lumens  130 , preferably spaced at intervals of 90°. The distal ends of the pullwires are anchored in the distal sections of the cannula  104  such that the distal section of the cannula can be made to deflect in a desired direction by pulling on the desired combination of pullwires.  FIG. 11E  illustrates in dashed lines V 1  a conical volumes defined by an exemplary movement pattern for the tool cannula  104 , and the corresponding volume V 2  defined by the tool  32  within the cannula  104 . 
     Actuation of the pullwires is achieved using features that during use are positioned outside the body. A deflection system is provided that allows the user to intuitively actuate the pullwires for a particular one of the tool cannulas  104  by manipulating the handle  152  of the instrument  32  that resides within that tool cannula. For example, if the user wishes to have the distal end of a tool move in a downward direction, s/he will intuitively raise the handle  152  of that tool to cause the corresponding tool cannula to deflect downwardly, thus moving the tool to the desired position. 
     Referring to  FIG. 3 , the proximal ends of the pullwires  128  extend from the proximal ends of the cannulas  104  and feed into a corresponding deflection system, which in the illustrated embodiments is a control gimbal  148 . 
     The gimbal  148  may be mounted to a work stand  150  as shown in  FIG. 12A . In use the work stand  150  may be set on top of the patient&#39;s torso or mounted to supports coupled to one or both side-rails of the surgical table, or carried on a cart. In either case, the work stand  150  is positioned to give the surgeon convenient and intuitive access to the handles  152  while s/he observes the procedure on an endoscopic display (not shown). As shown in  FIG. 12B , use of the system may be facilitated by providing a “cockpit” for the user, coupling an endoscopic display  154  to the work stand  150  that supports the control gimbals  148 , as well as the proximal controls for the endoscope  107 , and other ports  111  for passing instruments through the access cannula to the peritoneal space. 
     The work stand  150  is proportioned to allow the surgeon to position his or herself in a comfortable position with his/her hands on the handles  153  of the tools  32 . The work stand  150  preferably positions the tool handles  153  approximately 10-15 inches apart. 
     A preferred control gimbal  148  is shown in  FIG. 13 . It includes a base  168  mounted to the work stand (not shown in  FIG. 7 ) and having a tubular channel  170 . A c-shaped mount  172  is connected to the base  168  and includes a through hole  174  continuous with the lumen of the tubular end piece  170 . In a slight modification, the hole  174  might be accompanied by four separate through holes  174   a - d  might be used for receiving pull wires as in the  FIG. 19  embodiment. A ring  176  is pivotally mounted to the mount  172  at pivot bearings  178 . A semi-spherical ball  180  is pivotally mounted within the ring at pivots  182 . Four pull-wire ports  184  extend from the interior of the ball  180  to its outer surface. 
     Instrument port  186  includes side channels  190  having distal openings  192  and proximal openings  194 . The four pullwires  128  from the tool cannulas  104  extend through the tubular end piece  170  and each passes through hole  174 , through the hollow interior of the ball  180 , and out corresponding ones of the pull-wire ports  184  in the ball. The pullwires further extend into the instrument port side channels  190  and are secured there by anchors  196 . 
     Instrument port  186  has a lumen  188  extending proximally from the spherical ball  180 . The shaft  152  of an instrument  32  (see  FIG. 12A , not shown in  FIGS. 13-14 ) extends through the lumen  188  and the ball  180 , through hole  174  in the c-shaped mount  172 , and via tube  170  and the work stand  150  ( FIG. 12A ), into the corresponding tool cannula  104 . The operative end of the instrument  32  extends from the distal end of the tool cannula  104 . 
     When it becomes necessary for the surgeon to change the orientation of the distal end of an instrument  32 , s/he need only intuitively move the handle  152  of that instrument and the distal portion of the instrument will deflect accordingly as a result of the action of the gimbal on the pullwires of the tool cannula. Vertical movement of the handle  152  will cause the ball  180  to rotate relative to pivots  182 , thus applying tension to the upper or lower pullwire  128  to cause upward or downward deflection of the tool cannula  104  (and thus the distal end of the instrument  32 ). Lateral movement of the handle  152  will cause the ball  180  and ring  176  to rotate about pivots  178  and to therefore tension one of the side pullwires to change the lateral bend of the tool cannula  104 . The control gimbal allows combinations of vertical and lateral deflection, giving 360° deflection as shown in  FIG. 11E . Thus user may additionally advance/retract the tool  32  longitudinally within the tool cannula  104 , and/or axially rotate the tool  32  relative to the tool cannula when required. 
     The control gimbal  148  includes a locking mechanism that allows an instrument orientation to be temporarily fixed until further deflection is needed. This feature allows a user to fix a trajectory for multiple instruments that are to be sequentially used at a particular location. For example, once the orientation of a tool cannula  104  is set, a certain step in the procedure may be performed using a first instrument passed through that cannula. When a subsequent step requiring a different instrument is to be performed, the instruments are exchanged without moving the tool cannula  104 . This allows the second instrument to be advanced to the exact location at which it is needed without additional steering. 
     One exemplary locking mechanism includes a pair of locking screws  198  that are tightened as shown by arrows in  FIG. 15A  to lock the C-mount  172  to the ring  176  and to lock the ring  176  and the ball  180 . Alternatively, as shown in  FIG. 15B , a simple pneumatic shaft lock  200  could be employed on each of the gimbal&#39;s pivot axes. A solenoid or similar device might be used in place of the pneumatic lock  200 . 
     An alternate gimbal arrangement is shown in  FIGS. 16A and 16B . As shown, a cone shaped instrument port  202  is mounted to the proximal end of each cannula, and includes a diaphragm seal  204  having a slit  206  sealable around an instrument shaft  208  passed into the instrument port  202 . In  FIGS. 16A and 16B  only the handle of instrument shall  208  is shown to permit easier viewing of the surrounding features. 
     A gimbal  210  includes a collar  212  mounted on the instrument port  202  and four wings  214  radiating from the collar  212 . Each pullwire  128  is coupled to one of the wings  214 . Struts  216  extend proximally from the wings  214  and are joined to a sleeve  218  through which a portion of the instrument shaft  208  extends. Collar  212  is moveable relative to the instrument port  202 , and in particular collar  212  is rotatable about its central axis, and pivotable in multiple directions. Movement of the collar  212  places one or more of the pullwires  128  under tension and results in deflection of the cannula  104 . Since the instrument shaft  208  is coupled to the collar  212  by struts  216 , a user can manipulate the instrument shall  208  handle in an intuitive manner similar to a joystick to allow the user to steer the distal end of the cannula  104  in the desired direction. 
       FIG. 17  illustrates an alternative natural orifice surgical system  300 . System  300  includes features that are largely similar to those described elsewhere. For example, the system  300  uses the linkage  120   a  of  FIG. 11A , and a gimbal system similar to that described in connection with  FIG. 13 . The system  300  differs from the earlier embodiments in that it allows a user to adjust the sensitivity of the gimbals. In other words, the gimbal can be fine tuned such that the amount of deflection of the tool cannulas corresponds directly to the amount by which the user moves the tool handles  152  within the gimbal system, or the amount of deflection can be greater than or less than the corresponding movement of the tool handles. 
     Referring to  FIG. 19 , many of the features of the gimbal  302  are similar to those of gimbal  148  of  FIGS. 12 and 13 . These similar features include base  168 , which is coupled to frame  304 . Four through-holes  174   a - d  (three of which are visible in  FIG. 19 ), one for each pull wire, extend from c-shaped mount  172  through base  168 . The pullwires feed into the through-holes  174   a - d  from cable housings  175  that pass through the frame  304 . The more distal segments of the pullwires extend from the from the frame  304  into the tool cannulas  104  extending distally from the frame  304 . 
     A ring  176  is pivotally mounted to mount  172  at pivots  178 , and semi-spherical ball  180  is pivotally mounted within the ring  176  at pivots  182 . 
     The gimbal  302  of  FIG. 19  differs from the gimbal  148  of  FIGS. 12-13  in its inclusion of a microadjustment assembly  306 . As with the prior gimbal arrangements, the four pullwires of one of the tool cannulas terminate in the gimbal at 90 degree quadrants. Motion of the instrument shaft  152  ( FIG. 17 ) alters the tension on the various pullwires, which causes deflection of the tool cannula tip and corresponding movement of the tool within the tool cannula. The effect lever arm of each pull wire is altered in the  FIG. 19  embodiment by moving the point of termination of each pull wire towards or away from the gimbal&#39;s center of rotation. Moving the pullwire terminations away from the center of rotation causes movement of the tool cannula  104  to be amplified relative to the movement of the tool handle  152 , whereas moving the pullwire terminations towards the center of rotation decreases the amplification. 
     Ball  180  includes a distal surface  314  as shown in  FIG. 21A , and a planar proximal surface  316  as shown in  FIG. 20 . Four radial slots  318   a - d  extend through between the surfaces  314 ,  316 . Referring to  FIG. 20 , four sliding terminal plates  308   a - d , each including a pullwire terminal  310   a - d  and a proximally-extending follower pin  312   a - d , are positioned in contact with the planar proximal surface  316 . A peg  317  on the distal side of each terminal plate is received in the corresponding one of the slots  318   a - d.    
     Each pullwire used to deflect the tool cannula extends through one of the slots  318   a - d  and is anchored within a terminal  310   a - d  of one of the four sliding terminals  308   a - d .  FIG. 21A  shows the distal facing side  314  of the ball  180 , with the terminals  310   a - d  positioned over the slots  318   a - d . The pull wires themselves are not shown. 
     A tubular instrument port  320  is centrally positioned on the proximal surface  316  of the ball  180 . A retainer cap  322  covers the surface  316 , such that the instrument port  320  extends through a central opening  324  in the retainer cap. The sliding terminal plates  308   a - d  are sandwiched between the surface  316  and the retainer cap  322 .  FIG. 22  shows the cap  322  removed from the ball  180 . The inner, distal facing, surface of the cap  322  includes a spiral rib  326  defining a spiral shaped slot  328 . Each of the follower pins  312   a - d  of the terminal plates  308   a - d  are disposed within the spiral slot  328 . 
     A retaining ring  330  is engaged with the instrument port  320  and functions to hold the cap  322 , terminal plates  308   a - d , and ball  180  together such that the follower pins  312   a - d  remain within the spiral slot  328 . Cap is rotatable in clockwise and counterclockwise directions relative to the instrument port  320 . Rotation of the cap will increase or decrease the sensitivity of the gimbal system. More specifically, if the cap is rotated in a first direction, the spiral rib  326  will cause the pins  312   a - d  to advance through the spiral slot towards the outer circumference of the cap, causing the terminal plates to slide radially outwardly within slots, thereby increasing the sensitivity of the gimbal system. If the cap is rotated in a second direction, the pins will advance through the spiral slot toward the center of the cap, causing the terminal plates to slide radially inwardly within the slots so as to loosen the tension on the pullwires and to decrease the sensitivity of the gimbal, system. Markings  328  on the cap  322  and a corresponding pointer  330  instruct the user as to the level of sensitivity achieved when the cap is in one of the designated rotational positions relative to the pointer  330 . 
     In alternative configurations for adjusting gimbal sensitivity, the user may have the option to set different sensitivity levels for different ones of the pull wires. 
     The system is preferably packed in a kit containing instructions for use instructing the user to use the system in the manner disclosed herein. 
       FIG. 23  schematically illustrates use of the system of  FIGS. 9 and 10  as used such as for a cholecystectomy procedure. According to such a procedure, the access cannula  10  is placed transorally and moved into the peritoneal cavity via a left anterior stomach wall puncture. The access cannula  10  is anchored in a stomach incision as described above. The locking spine  102  is introduced into the peritoneal space and made rigid (via application of tension on the cables as described above) such that it is oriented towards the procedural site as shown. The liver retractor  35   a  is used to lift and retract the liver superiorly away from the gallbladder and the operational area of the instruments  32 . Instruments  32  are advanced through the tool cannulas and used to perform the procedure. Tool cannulas  104  are deflected as needed to manipulate the instruments. Whereas prior art laparoscopic procedures involve formation of three surgical ports or incision X (tool port), Y (endoscope port), Z (tool port) to perform the cholecystectomy procedure, use of the disclosed system allows the procedure to be performed less invasively while allowing the surgeon to carry out the procedure from the same familiar perspective from which s/he would have performed the laparoscopic procedure. 
     The embodiments disclosed above utilize locking spine devices in natural orifice procedures to locate tools at or near the abdominal walls such that the tools may be manipulated in a way that is intuitive to the surgeon given his/her experience with laparoscopic and/or open surgical techniques. Other systems that achieve this objective without the use of a locking spine are also useable and fall within the scope of this disclosure. One example is shown in  FIG. 24  in which a system  400  may be attached to the interior of the abdominal wall using a screw  402 , t-bar  404 , inflatable balloon anchor, expandable braid, or similar device embedded in the facial layer of the stomach wall W. According to this embodiment, the system  400  includes features that support a procedural cannula  406  introduced into the peritoneal space via a natural orifice as described above. In the example shown, the procedural cannula  406  is passed through or engaged with a guide ring  408  that helps to orient the distal end  410  of the procedural cannula  406 , and thus tools  412  passed through the procedural cannula  406 , towards the treatment site. As another alternative embodiment, the system may use magnetism to support, retain and/or locate tools at the desired vantage point, such as near the inside of the abdominal wall. This embodiment might use cannulas having magnetic features within the body, and an external electromagnetic outside the body. Alternatively, the embodiment might employ a steel/iron plate outside the body and magnetic cannulas that are attracted to the steel/iron plate. 
     While certain embodiments have been described above, it should be understood that these embodiments are presented by way of example, and not limitation. While these systems provide convenient embodiments for carrying out this function, there are many other instruments or systems varying in form or detail that may alternatively be used within the scope of the present invention. This is especially true in light of technology and terms within the relevant art(s) that may be later developed. Moreover, the disclosed embodiments may be combined with one another in varying ways to produce additional embodiments. 
     Any and all patents, patent applications and printed publications referred to above are incorporated by reference, including those relied upon for purposes of priority.