Abstract:
The invention provides surgical or diagnostic tools and associated methods that offer improved user control for operating remotely within regions of the body. These tools include a proximally-located actuator for the operation of a distal end effector, as well as proximally-located actuators for articulational and rotational movements of the end effector. Control mechanisms and methods refine operator control of end effector actuation and of these articulational and rotational movements. A rotation lock provides for enablement and disablement of rotatability of the end effector. The tool may also include other features. A multi-state ratchet for end effector actuation provides enablement-disablement options with tactile feedback. A force limiter mechanism protects the end effector and manipulated objects from the harm of potentially excessive force applied by the operator. An articulation lock allows the fixing and releasing of both neutral and articulated configurations of the tool and of consequent placement of the end effector.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to U.S. Ser. No. 60/813,650 of Danitz and Hinman, entitled “Devices having locking rotation knobs and methods for using the same” and filed on Jun. 13, 2006, the disclosure of which is incorporated herein by reference. This application is further related to the following concurrently filed US patent applications: “Tool with articulation lock” of Hegeman, Danitz, Hinman, and Alvord, “Tool with force limiter” of Hinman and Bertsch, “Tool with multi-state ratcheted end effector” of Hinman, and “Articulating tool with improved tension member system” of Hegeman, Danitz, Bertsch, Hinman, and Alvord. 
     
     INCORPORATION BY REFERENCE 
       [0002]    All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 
         [0003]    1. Field of the Invention 
         [0004]    This invention relates to articulating mechanisms and applications thereof, including the remote guidance and manipulation of surgical or diagnostic instruments tools. 
         [0005]    2. Background of the Invention 
         [0006]    The popularity of minimally invasive surgery has been growing rapidly due to its association with decreased complication rates and post-surgical recovery times. The instruments employed are generally hand-operable and typically include a handle, a shaft that may or may not be rotatably attached to the handle, a rotation knob rigidly fixed to the proximal end of the shaft near the handle in instances where the shaft is rotatably attached to the handle, and a tool or end effector attached to the distal end of the shaft. To manipulate the instruments, they are held at the handle and typically pivoted about a pivot point defined by the entry incision, i.e., the incision made in the abdominal wall for laparoscopic procedures. The end effector may also be rotated about the shaft axis, as for example, by rotating a rotation knob, if present. In use, these instruments have limited control and range of motion and become physically taxing as the length of the procedure increases. 
         [0007]    Surgical procedures such as endoscopy and laparoscopy typically employ instruments that are steered within or towards a target organ or tissue from a position outside the body. Examples of endoscopic procedures include sigmoidoscopy, colonoscopy, esophagogastroduo-denoscopy, and bronchoscopy, as well as newer procedures in natural orifice transluminal endoscopic surgery (“NOTES”). Traditionally, the insertion tube of an endoscope is advanced by pushing it forward, and retracted by pulling it back. The tip of the tube may be directed by twisting and general up/down and left/right movements. Oftentimes, this limited range of motion makes it difficult to negotiate acute angles (e.g., in the rectosigmoid colon), creating patient discomfort and increasing the risk of trauma to surrounding tissues. 
         [0008]    Laparoscopy involves the placement of trocar ports according to anatomical landmarks. The number of ports usually varies with the intended procedure and number of instruments required to obtain satisfactory tissue mobilization and exposure of the operative field. Although there are many benefits of laparoscopic surgery, e.g., less postoperative pain, early mobilization, and decreased adhesion formation, it is often difficult to achieve optimal retraction of organs and maneuverability of conventional instruments through laparoscopic ports. In some cases, these deficiencies may lead to increased operative time or imprecise placement of components such as staples and sutures. 
         [0009]    Recently, surgical instruments, including minimally invasive surgical instruments, have been developed that are more ergonomic and which have a wider range of motion and more precise control of movement. These instruments may include mechanisms that articulate using a series of links coupled with one or more sets of tension bearing members, such as cable. As with conventional instruments used in minimally invasive surgery, rotation of the shaft and end effector with respect to the handle is an important feature of cable and link type instruments to aid with dissecting, suturing, retracting, knot tying, etc. Ergonomic, flexible, and intuitive mechanisms that facilitate manual control of the end effectors of such instruments are also important factors as medical procedures become more advanced, and as surgeons become more sophisticated in operating abilities. Particularly with regard to rotation, however, inadvertent rotation and larger torques can be associated with articulating instruments, as loading on the end effector that can be off axis from the shaft axis. Consequently, new mechanisms and methods for controlling rotation of surgical instruments are desirable. 
       SUMMARY OF THE INVENTION 
       [0010]    It may at times be desirable to change and then maintain the orientation of the distal end of a steerable or articulating instrument. This invention provides methods and devices for rotating, articulating, locking or otherwise maintaining the shape and orientation of steerable and articulating instruments. 
         [0011]    Embodiments of the inventive device include proximal portion and a distal portion, a shaft interposed between the proximal portion and the distal portion. The shaft includes an articulation mechanism for manipulating the angular orientation of the end effector with respect to the shaft, and a shaft rotation mechanism which permits rotation of the articulation mechanism and the distal portion with respect to the handle. The rotation mechanism has a first state in which the articulation mechanism and distal portion are not rotatable with respect to the handle and a second state in which the articulation mechanism and distal portion are rotatable with respect to the handle. Some embodiments of the device may be a surgical or diagnostic tool, and some embodiments may include an end effector disposed at the distal portion of the device. 
         [0012]    Some embodiments of a shaft rotation mechanism include a handle engagement surface that is engaged with the handle in the first state, thus preventing rotation, and is not engaged with the handle in the second state, thereby permitting rotation. In some embodiments, the handle engagement surface includes a plurality of teeth and the handle also includes a complementary plurality of teeth that are adapted to engage the teeth of the handle engagement surface, when the shaft rotation mechanism is in its first state, such that rotation is not allowed. In some embodiments, the handle includes a movable lock actuator that supports the plurality of teeth on the handle. 
         [0013]    In some embodiments, the shaft rotation mechanism is biased toward this first and non-rotatable state. In some embodiments this bias includes a spring, which biases the shaft rotation mechanism toward the non-rotatable state. 
         [0014]    Some embodiments of the shaft rotation mechanism include a shaft engagement mechanism that is engaged with the articulation mechanism in both the first and second states of the rotation mechanism. This shaft engagement mechanism may be movable proximally and distally along the shaft between the first (non-rotatable) state and the second (rotatable) state. The shaft rotation mechanism may further include a shaft rotation actuator that engages with the articulation mechanism such that the rotation of the shaft rotation actuator rotates the articulation mechanism and the distal portion of the device with respect to the handle. In such embodiments, the shaft rotation actuator cannot rotate with respect to the handle when the shaft rotation mechanism is in the first state. 
         [0015]    In some embodiments of the tool, the articulation mechanism includes a pair of a proximal link and a distal link spaced apart from each other, and configured such that movement of the proximal link causes corresponding relative movement of the distal link and angular movement of the distal portion of the tool, and, if present, the end effector with respect to the shaft. In some embodiments, rather than a single distal and proximal pair of links, the tool includes a plurality of pairs of proximal and distal links, such that movement of the proximal link of each pair causes corresponding relative movement of the distal link of the pair and angular movement of the end effector with respect to the shaft. In some embodiments, the shaft rotation mechanism includes a sliding engagement with a proximal link. In some embodiments the articulation mechanism further includes an articulation lock having an engaged position and a disengaged position, such that when in the engaged position, the articulation lock impedes relative movement of the proximal links of each pair of links, thereby preventing relative movement of the distal link of each pair of links. 
         [0016]    Embodiments of the invention include a method of using a device, the device as summarized above, where the method of use includes placing the distal portion of the device and the end effector, if present at the distal portion, at a target site, moving the handle of the tool angularly with respect to the shaft and thereby moving the distal portion angularly with respect to the shaft, rotating the handle with respect to the shaft without rotating distal portion, and applying rotational torque to the distal portion by rotating the handle. 
         [0017]    The step of rotating the handle with respect to the shaft may include moving a shaft rotation actuator from a first position to a second position. The method may further include moving the shaft rotation actuator from the second position to the first position prior to the step of applying rotational torque to the distal portion of the device and the end effector, if present. In some embodiments the first position is proximal to the second position. 
         [0018]    The step of rotating the handle with respect to the shaft may include rotating the handle with respect to the shaft rotation actuator. Rotating the handle may include rotating the handle with respect to the shaft rotation actuator while the shaft rotation actuator is in the second position. 
         [0019]    The method of using a device such as an articulatable surgical or diagnostic tool, as summarized above, may further include controlling permissibility of relative angular movement between the handle and the shaft. The step of controlling permissibility may include impeding angular movement by moving an articulation lock from a disengaged position to an engaged position, wherein in the engaged position the articulation lock impedes movement of the proximal link and corresponding relative movement of the distal link. The articulation lock may include a slidable sleeve, and moving the lock may include sliding the sleeve along the shaft, and moving the sleeve along the shaft may be in a proximal direction. The step of controlling permissibility may include permitting angular movement by moving the articulation lock from the engaged position back to the disengaged position to permit relative angular movement between the handle and the shaft. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings which are briefly described below. 
           [0021]      FIG. 1  is a front perspective view of a surgical tool. 
           [0022]      FIG. 2  is perspective view of a surgical tool in an articulated position. 
           [0023]      FIG. 3  is an exposed side view of a surgical tool with an end effector actuator and an end effector both in an open position. 
           [0024]      FIG. 4  is an exposed side view of a surgical tool with an end effector actuator and an end effector both in a closed position. 
           [0025]      FIG. 5  is a side view of the proximal portion of a tool, showing the handle and proximal end of the shaft, with an articulation locking sleeve in a distal and unlocked position. 
           [0026]      FIG. 6  is a side view of the proximal portion of a tool, showing the handle and proximal end of the shaft, with an articulation locking sleeve in a proximal and locked position. 
           [0027]      FIG. 7  is an exposed view of a portion of a tool from an overhead distal looking perspective, the portion including the handle, locking rotation knob, and a proximal link. 
           [0028]      FIG. 8  is a cross-sectional view of a portion of the handle, knob and a proximal link. 
           [0029]      FIG. 9  is an exposed view of a handle from a distal-looking perspective. 
           [0030]      FIG. 10  is an exposed view of a handle from a proximal-looking perspective. 
           [0031]      FIG. 11  is a proximal-looking perspective view of a locking rotation knob showing an inner member and an outer member separated from each other. 
           [0032]      FIG. 12  is a proximal-looking perspective view of a locking rotation knob with inner and outer members fitted together. 
           [0033]      FIG. 13  is a distal-looking perspective view of a locking rotation knob showing an inner member and an outer member separated from each other. 
           [0034]      FIG. 14  is a distal-looking perspective view of a locking rotation knob showing an inner member and an outer member fitted together. 
           [0035]      FIG. 15  is a side view of another embodiment of surgical tool, with a different embodiment of an articulation locking sleeve in a distal and unlocked position, and with an end effector actuator and an end effector both in a closed position. 
           [0036]      FIG. 16  is a side view of the embodiment shown in  FIG. 15 , but with the articulation locking sleeve in a proximal and locked position. 
           [0037]      FIG. 17  is a side view of an embodiment of a tool with a rotation locking knob that is non-self locking, the rotation lock in an unlocked, disengaged proximal position. 
           [0038]      FIG. 18  is a side view of the embodiment shown in  FIG. 17 , but with the rotation lock in a locked or engaged position, the lock having been moved forward to a distal position. 
           [0039]      FIG. 19  is a cross sectional view of the embodiment shown in  FIG. 17 , with the locking rotation knob in its unlocked position. 
           [0040]      FIG. 20  is a cross sectional view of the embodiment shown in  FIG. 17 , with the locking rotation knob in its locked or engaged position. 
           [0041]      FIGS. 21A-C  show various views of an exemplary sliding lock as shown in  FIG. 17 .  FIG. 21A  shows a rotated front view,  FIG. 21B  shows a rotated end view, and  FIG. 21C  shows a top front view. 
           [0042]      FIG. 22  is a partial cut-away view of the lock embodiment shown in  FIG. 17 , showing a portion of the handle. 
           [0043]      FIG. 23  is a perspective view of another embodiment of a non-self locking rotation lock comprising a trigger lock. 
           [0044]      FIG. 24  is a perspective view of another embodiment of a non-self-locking rotation lock comprising a friction lock with a lever, with the lock in an engaged or locked position. 
           [0045]      FIG. 25  is a perspective view of the embodiment shown in  FIG. 24 , where the lock has been rotated by use of the lever so that the friction lock has disengaged rotation knob in a proximal direction, thus unlocking rotation knob. 
           [0046]      FIG. 26  is a distal-looking perspective view of a spindle having a proximal link formed on its distal end. 
           [0047]      FIG. 27  is a proximal-looking perspective view of a spindle having a proximal link formed on its distal end. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0048]    Steerable articulating instruments are described in U.S. Pat. No. 7,090,637; US  2005/0107667; US Publication Nos. US 2005/0273084; US 2005/0273085; US 2006/0111209, and US 2006/0111210. The articulating mechanisms of the tools described in those publications use multiple pairs of segments or links that are controlled, e.g., by multiple sets of cables. Depending upon the specific design of the device, the links can be discrete segments (as described, e.g., in U.S. Pat. No. 7,090,637) or discrete portions of a flexible segment (as described, e.g., in US 2005/0173085). The instrument may also include steerable or controllable links separated by spacer links, e.g., as described in US 2005/0273084 and US 2006/0111210. 
         [0049]    When using such articulating instruments, a user may manipulate the proximal end of the instrument, and thereby move one or more proximal links of the articulation mechanism. This movement results in relative movement of the distal link(s) corresponding to the proximal link(s). It may at times be desirable to lock or otherwise maintain the straight or bent shape of the instrument. In certain embodiments of this invention, the shape of the instrument is maintained by preventing movement of at least one of the proximal links with respect to the rest of the instrument. In other embodiments, a friction-based articulation locking mechanism locks all links, proximal and distal; these embodiments are disclosed in the concurrently filed and hereby incorporated application “Tool with articulation lock” of Hegeman, Danitz, and Alvord. 
         [0050]      FIGS. 1-6  show an articulatable tool  100  with an end effector  102  at its distal end and an end effector actuator  104  within a handle  106  at its proximal end. Instrument  100  may be used, e.g., in a laparoscopic procedure requiring grasping or cutting within a patient. Exemplary embodiments of the tool  100  may also may useful in endoscopic procedures, particularly when, as in some embodiments, the tool has a flexible shaft. Still other embodiments may be used for percutaneous procedures, such as a catheter. Still other embodiments include devices that are directed toward natural orifice transluminal endoscopic surgery (“NOTES”). Embodiments of the invention may include a wide variety of tools, some with medical or diagnostic purposes, and others that are applied to other types of tasks where the articulational capabilities of the tool provide benefit. 
         [0051]    Continuing now with some description of links that typically form the basis of articulating mechanisms included with some embodiments of the tools with rotatable mechanisms, links may be understood as a discrete portion of a tool that are capable of movement with respect to an adjacent portion. Links typically occur in complementary or corresponding pairs, one link being proximal on the tool, the other link being distal, the two links being operably connected, typically by tension bearing members such as cables. Proximal articulation links  108  and  110  extend distally from handle  106 , and complementary distal articulation links  112  and  114  extend proximally from end effector  102 . Proximal link  108  is connected to and moves with handle  106 . In the embodiment shown, proximal link  108  is formed on the distal end of spindle  117  which is rotatably held in handle  106 , as best seen in  FIGS. 8 ,  26 , and  27 . Likewise, complementary distal link  112  is connected to and moves with end effector  102 . Distal link  112  may be integrally formed on the proximal end of end effector body  119 , as best seen in  FIG. 3 . An elongated shaft  116  is disposed between complementary pairs of links proximal and distal to it. In the tool embodiment shown in  FIG. 8 , a bushing  115  separates links  110  and  112 . Bushing  115  has convex surfaces at its proximal and distal ends that engage with corresponding concave surfaces on links  108  and  110 . Further details of the types links suitable for use with this invention, such as ball and socket joints, and pivoting single-degree-of freedom joints, or any type of joint where friction affects the movement of links relative to each other, may be found in US 2005/0273084 US 2006/0111209, and US 2006/0111210. 
         [0052]    As seen in  FIG. 3 , a set of tension bearing members or control cables  118  is attached to proximal link  108 , extends through proximal link  110 , shaft  116 , and distal link  114 , and is attached to distal link  112 . A second set of control cables  120  is attached to proximal link  110 , extends through shaft  116  and is attached to distal link  114 . In this embodiment, there are three control cables  118  in the first set and three control cables  120  in the second set. It should be appreciated, however, that other numbers of control cables may be used to connect corresponding proximal and distal links. In addition, mechanisms other than cables may be used to connect corresponding links. 
         [0053]    As shown in  FIG. 2 , which shows a tool in an articulated position, movement of handle  106  and proximal link  108  with respect to proximal link  110  moves end effector  102  and distal link  112  in a relative and corresponding manner. Likewise, movement of proximal link  110  with respect to shaft  116  moves distal link  114  with respect to shaft link  116  in a relative and corresponding manner, also as shown in  FIG. 2 . This relative articulation movement provides a way for a user to remotely manipulate the end effector through movement of the handle. Angular movement of the end effector may either mirror the movement of the handle or be reciprocal to it;  FIG. 2  shows the end effector moving in a manner that mirrors the movement of the handle. 
         [0054]    In the embodiment illustrated in  FIGS. 1-4 , the end effector  102 is a pair of jaws. Actuation force is transmitted from end effector actuator  104  through a transmission that includes a linearly movable tension bearing member or rod  125  and a rotatable rod actuator  122 , as shown in  FIGS. 3 and 4 . In some embodiments, rod  125 , in addition to being a tension bearing member, is further able to function as a compression bearing member such that it can transfer a compressive load from the end effector actuator distally to the end effector. The depicted embodiment of the end effector actuator  104  may be referred to, for example, as a moveable member, or a thumb piece, as it is typically operated by the thumb of a user. Other embodiments of end effectors (surgical, diagnostic, etc.) and end effector actuators may be used with the articulating tool of this invention. 
         [0055]    Turning now to description of mechanisms that reversibly prevent or permit articulation in articulating tools in order to maintain a particular position of the end effector with respect to the shaft (whether the position is a straight or neutral position, or an articulated position) the articulating tool of this invention may include an articulation lock. The articulation lock embodiment in the form of a rigid sleeve described below is merely one example. As noted above, numerous other embodiments are provided in the concurrently filed application of Hegemen et al., entitled “Tool with Articulation Lock”, which is hereby incorporated into this application by this reference. 
         [0056]    Thus, by way of an articulation lock example, the embodiment of an articulation lock shown in  FIGS. 1-6  includes a movable rigid sleeve  130 . In the unlocked position, as shown in  FIGS. 1-5 , sleeve  130  is distal to proximal links  108  and  110 , and they are thus exposed to view. In the locked position shown in  FIG. 6 , however, sleeve  130  has been moved proximally to a position adjacent to and covering links  108  and  110  as well as the proximal end of shaft  116  which, accordingly, are hidden in this view. The movable sleeve, in this position, thereby physically blocks relative movement between links  108  and  110  and between link  110  and shaft  116 . In this locked position, relative movement between distal links  112  and  114  and between link  114  and shaft  116  is prevented as well. 
         [0057]    As shown in  FIG. 6 , a sleeve support mechanism  132  extends proximally from shaft  116  to provide sliding support for sleeve  130 . A distal stop  134  provides a limit of distal movement of sleeve  130 ; a similar stop (not shown) is provided on or within handle  104  to limit proximal movement of sleeve  130 . Detents, ridges or other mechanisms may be provided to maintain the sleeve in its proximal or distal positions and to provide tactile feedback to the user regarding the position of the sleeve. 
         [0058]    Turning now to embodiments of an inventive rotation lock, the end effector  102  of tool  100  may be rotated with respect to handle  106  and then locked so that further rotation between end effector  102  and handle  106  is prevented. A rotation knob  101  is disposed at least partially around link  108 . In the locked position, teeth  103  formed on the proximal face of knob  101  engage corresponding teeth  105  formed on a distal face of handle  106 , as seen in  FIG. 10 . (Handle  106  may be made in two pieces. Two views of one of the two pieces are shown in  FIGS. 9 and 10 .) In this embodiment, the rotation lock is self-locking due to the action of a spring  107  biasing knob  101  proximally into engagement with handle  106 , as shown in  FIG. 8 . 
         [0059]    When moved distally against the bias of spring  107 , the teeth  103  of knob  101  disengage from the teeth  105  of handle  106 . This disengagement permits knob  101 , links  108  and  110 , shaft  116 , links  112  and  114 , and end effector  102  to rotate with respect to handle  106 . This relative rotation may be effected by rotating handle  106  while the rest of tool  100  remains stationary, by holding handle  106  stationary and rotating the rest of tool  100  such as by turning knob  101 , or by a combination of the two. This action permits the end effector to be rotated in any articulated configuration. When the end effector has been rotated the desired amount relative to handle  106  by rotating knob  101  and/or handle  106 , release of knob  101  permits the two sets of teeth to re-engage, thereby locking the device against further rotation. In the embodiment shown, spindle  117  is rotatably fixed relative to knob  101  by fins  135  formed on spindle  117  (as best seen in  FIGS. 26 and 27 ) which are slidably received within slots  136  formed in inner member  109  of knob  101  (as best seen in  FIG. 11 ). Bushing  115 , in turn, may be rotatably fixed relative to spindle  117  by a torque transmitting pin or flanges  137  of bushing  115  (as best seen in  FIG. 8 ) engaging slots  138  of proximal link  108  on spindle  117  (as best seen in  FIG. 27 ). Similar torque-transmitting features may be provided along tool  100  between bushing  115  and end effector  102 , as described in detail in U.S. application publication number US  2006 / 0111210 . With this arrangement, the rotational orientation of end effector  102  relative to handle  106  may be locked when teeth  103  of knob  101  engage teeth  105  of handle  106 , as described above. 
         [0060]    In one embodiment, knob  101  is made in two pieces, an inner member  109  and an outer member  111 , as shown in  FIGS. 11-14 . The teeth  103  are formed on the inner member  109 . Indentations or knurls  113  may be formed on knob  101  to facilitate grasping. 
         [0061]    In other embodiments, the rotation knob may not be self-locking in the sense that the locking mechanism is not biased toward a locked position, and may have a manually actuatable lock, such as a sliding lock. In some embodiments, the engagement surfaces between the rotation knob and the handle may use fewer locking teeth or other engagement features, such as pins, friction surfaces, etc. While the end effector shown in  FIG. 1  is a pair of jaws, other end effectors may be used, such as meters, probes, retractors, dissectors, staplers, clamps, graspers, scissors, cutters, ablation elements, etc. 
         [0062]      FIGS. 15-16  show another embodiment of the invention. Articulatable tool  700  has an end effector  702  at its distal end and an end effector actuator  704  within a handle  706  at its proximal end. Tool  700  may be used, e.g., in a laparoscopic procedure requiring grasping or cutting within a patient. Proximal articulation links  708  and  710  extend distally from handle  706 , and distal articulation links  712  and  714  extend proximally from end effector  702 . Proximal link  708  is connected to an moves with handle  706 . Likewise, distal link  712  is connected to and moves with end effector  702 . An elongated shaft  716  is disposed between the proximal links and the distal links. The linkage between pairs of proximal and distal links may be with cables as in the embodiment of  FIG. 1  or by any other suitable means. Likewise, operation of end effector  702  may be as in the  FIG. 1  embodiment. 
         [0063]    As in the embodiment of  FIGS. 1-14 , movement of handle  706  and proximal link  708  with respect to proximal link  710  moves end effector  702  and distal link  712  in a relative and corresponding manner. Likewise, movement of proximal link  710  with respect to shaft link  716  moves distal link  714  with respect to shaft  716  in a relative and corresponding manner. This relative articulation movement provides a way for a user to remotely manipulate the end effector through movement of the handle. 
         [0064]    In order to maintain a particular position of the end effector with respect to the shaft, the articulating tool of this embodiment has an articulation lock that controls the permissibility of angular movement between the distal portion of the tool and an end effector, if present there, with respect to the shaft. In the embodiment shown in  FIGS. 15-16 , the articulation lock includes a movable rigid sleeve  730 . In the unlocked position shown in  FIG. 15 , sleeve  730  is distal to proximal links  708  and  710 . In the locked position shown in  FIG. 16 , however, sleeve  730  has been moved proximally on sleeve support  732  to a position adjacent to and covering links  708  and  710  as well as the proximal end of shaft  716 , thereby blocking relative movement between links  708  and  710  and between link  710  and shaft  716 . In this locked position, relative movement between distal links  712  and  714  and between link  714  and shaft  716  is prevented as well. 
         [0065]    Tool  700  has a rotation lock knob  747  that functions in a manner similar to that of  FIGS. 1-14 . When the device&#39;s articulation lock is in the locked position, pull tabs  744  nest with grooves  745  formed in the rotation lock knob  747 . 
         [0066]      FIGS. 17 and 18  illustrate another variation of the rotation knob, where the rotation knob is not-self locking. Shown there is a portion of a surgical instrument  1000 . As with the surgical instruments described above, the surgical instrument  1000  of  FIG. 17  has a handle  1002  having a stationary member  1004  and a movable member  1006 . Also shown is a rotation knob  1008  having teeth  1010  for engaging with teeth  1012  on a sliding lock  1014 . In this variation, there are only a few teeth  1012  on the sliding lock  1014 , which was described above as an alternative, and it should be understood that the description of teeth above (and their alternatives such as pins, etc.) apply here as well. 
         [0067]    The sliding lock  1014  is used to lock the rotation knob. Specifically, the sliding lock  1014  is moved distally or proximally, to engage, or disengage, as the case may be the teeth  1010  on rotation knob  1008  from teeth  1012  on sliding lock  1014 . In its resting position, the sliding lock may be in either the locked or unlocked position, as will be described in more detail below. In  FIG. 17 , the sliding lock is shown in its unlocked, or disengaged, position.  FIG. 18  shows the sliding lock in its locked, or engaged, position (e.g., after moving the sliding lock distally forward). 
         [0068]      FIG. 19  shows a cross-section of a portion of the surgical instrument  1000  of  FIG. 17 , where the rotation knob is in its unlocked position. Shown there is handle  1002  having stationary member  1004  and movable member  1006 . Also shown is rotation knob  1008  with most proximal link  1016  sitting within a bore of rotation knob  1008 . The proximal link  1016  may be fixedly engaged within or to rotation knob  1008 , or may be integral with (e.g., manufactured as a single component) rotation knob  1008 . As with the instruments comprising a self-locking rotation knob described above, the instrument here also has a push-pull wire  1018  to actuate the end effector (not shown). Termination piece  1020  of push-pull wire  1018  is rotatably connected to termination piece  1022  of handle  1002  at termination piece end  1024 . Washer  1026  is placed around boss  1003  of termination piece  1020  and e-ring  1028  sits within a slot (not shown) on boss  1003 . Also shown in a like fashion to the surgical instruments described above is dog-tipped set screw  1030  that is threaded within thread hole  1032  and engages circumferential slot  1034  on proximal link  1016 . As described above, it should be understood that proximal link  1016  and push-pull wire  1018  can be rotatably connected to handle  1002  in other ways commonly known in the art. As can be seen in this cross-sectional view, the sliding lock  1014  does not sit around the entire circumference of the handle (although it may be designed as such if desirable). Ball plunger  1036  sits within and is attached to (e.g., screwed to) ball plunger hole  1042 . The ball of ball plunger  1036  is shown sitting within proximal detent  1040 . In this view, the sliding lock is in its unlocked, or disengaged position. When the sliding lock is pushed distally forward, the ball of ball plunger  1036  engages distal detent  1038  and maintains teeth  1010  of rotation knob  1008  and teeth  1012  of sliding lock  1014  in an engaged position, as shown in  FIG. 20 . It should also be understood that while ball plungers are described with reference to  FIGS. 20 and 21 , it should be understood that any suitable mechanism may be used to maintain the sliding lock  1014  in the engaged or disengaged position. For example, other plungers, buttons, and the like may be used. 
         [0069]      FIGS. 21A-21C  show various views of an exemplary sliding lock  1014 . Specifically,  FIG. 21A  shows a rotated front view,  FIG. 21B  shows a rotated end view, and  FIG. 21C  shows a top front view. Shown throughout the views are teeth  1012  for engaging with teeth on rotating knob  1008 , ball plunger hole  1042  into which the ball plunger is secured, and flange  1400  for engaging within a slot (shown and described below with reference to  FIG. 22 ) on the handle  1002 . In this way, the sliding lock is able to slide axially, but is prevented from rotating. While the sliding lock shown here is generally semi-circular in geometry, any suitable geometry may be used. 
         [0070]      FIG. 22  shows a partial cut-away view of a portion of handle  1002 , having stationary member  1004 . Also shown are distal  1038  and proximal  1040  detents for engaging and retaining the ball of ball plunger  1036 . Slot  1500  is also shown. As mentioned briefly above, slot  1500  is configured to engage flange  1400  on sliding lock  1014 . While the slot  1500  shown in  FIG. 21  is configured to have a “T” shape, and corresponding flange  1400  is configured to have a corresponding “T” shape, the slot  1500  and flange  1400  need not have these geometries. Indeed, any suitable shapes may be used. Also shown in  FIG. 22  is bore  1502  through which proximal link  1016  enters. 
         [0071]    While various types of locking mechanisms have been just described (e.g., self-locking rotation knobs, sliding locks in combination with a rotation knob), it should be understood that any suitable locking mechanism may be used with the rotation knobs and surgical instruments described herein. For example, one alternative to a sliding lock used in combination with a rotation knob is the use of a trigger lock as shown in  FIG. 23 . Shown there is a proximal portion of surgical instrument  1600 , comprising a handle  1602 , a rotation knob  1604  having teeth  1606 , and a trigger lock  1608 . In this variation, the trigger lock  1608  is actuated by depressing the lock, which in turn disengages the teeth  1606  on rotation knob  1604  from teeth (not shown) on trigger lock  1608 , or vice versa. Trigger lock  1608  is held in place by, and is pivotably connected to handle joint  1610 . As with the variations described above, there may be any number of different variations on the acceptable teeth (or pins with holes, etc.). Similarly, the trigger lock may have any suitable geometry or configuration. 
         [0072]    Another alternative to a sliding lock used in combination with a rotation knob is the use of a friction lock as shown in  FIGS. 24 and 25 . Shown in  FIG. 24  is a proximal portion of surgical instrument  1700 , comprising a handle  1702 , a rotation knob  1704 , and a friction lock  1706 . The friction lock  1706  has a lever  1708 , for moving the lock  1706  about threads  1710 . Internal threads (not shown) on the friction lock  1706  engage threads  1710 . When a user operates lever  1708  (e.g., with one or more fingers), the friction lock  1706  is rotated about threads  1710 . In  FIG. 24 , the rotation knob  1704  is shown in its locked position. That is, friction lock  1706  is rotated about thread  1710  until it has engaged rotation knob  1704  locking it in place (like a brake or a clutch). Alternative methods of engaging the friction lock  1706  and rotation knob  1704  may also be used. For example, friction lock  1706  could be designed into a toggle clamp mounted to handle  1702 . Other mechanisms known in the art may also be used.  FIG. 25  shows the surgical instrument of  FIG. 24  where the friction lock  1706  has been rotated by use of lever  1708  so that friction lock  1706  has disengaged rotation knob  1704  in a proximal direction, thus unlocking rotation knob  1704 . It should be understood that while the trigger lock and friction lock described just above are suitable alternatives to a sliding lock, any suitable locking mechanism may be used to intermittently prevent rotation of the shaft and end effector. 
         [0073]      FIGS. 26 and 27  show further details of spindle  117 , which in the embodiment shown has a proximal link  108  formed on its distal end. As previously described, spindle  117  may be provided with fins  135  for rotationally fixing spindle  117  relative to knob  101  (as shown in  FIG. 8 ). Spindle  117  may also be provided with bearing surface  1800  for allowing knob  101  to slide axially over spindle  117 . Additionally, spindle  117  may be provided with bearing surface  1802  for allowing spindle  117  and proximal link  108  to rotate in handle  106  (as shown in  FIG. 8 ). In this embodiment, spindle  117  is also provided with slot  1804  to permit axial loads to be transmitted from proximal link  108  to handle  106  (as also shown in  FIG. 8 ). Through holes  1806  may be provided in link  108  for receiving the proximal ends of cables  118  (shown in  FIG. 3 ) that interconnect proximal link  108  with distal link  112 . In the embodiment shown in the figures, only three of the six holes  1806  of proximal link  108  are used to connect cables  118  to link  108 . The proximal ends of cables  118  may be secured to link  108  by a variety of alternative processes as fully described in a concurrently filed and hereby incorporated U.S. patent application entitled “Articulating tool with improved tension member system” by Hegeman, et al. 
         [0074]    While the inventive surgical instruments and devices have been described in some detail by way of illustrating the invention, such illustration is for purposes of clarity of understanding only. It will be readily apparent to those of ordinary skill in the art in light of the teachings herein that certain changes and modifications may be made thereto without departing from the spirit and scope of the appended claims. For example, while the rotation knobs described herein have typically been in the context of a tool with an articulating mechanism comprising at least two links, the rotation knobs may be used in an instrument comprising only a single link, a multiplicity of links, with any number of cables or cable sets operably connecting the links. Further, in some variations it may be desirable to have the handle affixed to a shaft, rigid or flexible, with or without a dedicated end effector. Further still, while the context of the invention is considered to be surgical or medical diagnostic procedures, embodiments of the rotation lock mechanism or tools having such a mechanism may have utility in non-medical contexts as well.