Patent Publication Number: US-2023157687-A1

Title: Methods and systems for controlling staple firing

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/941,476, filed Jul. 28, 2020, which is a continuation of U.S. patent application Ser. No. 15/836,506, filed Dec. 8, 2017 and issued as U.S. Pat. No. 10,758,226, which is a continuation of U.S. patent application Ser. No. 14/949,827, filed Nov. 23, 2015 and issued as U.S. Pat. No. 9,877,718, which is a divisional application of U.S. patent application Ser. No. 13/350,512, filed Jan. 13, 2012 and issued as U.S. Pat. No. 9,226,750, and claims the benefit of U.S. Provisional Patent Application No. 61/443,148, filed Feb. 15, 2011, each of which is incorporated herein by reference in its entirety. 
     The present application is related to U.S. application Ser. No. 12/705,418 entitled “Cut and Seal Instrument,” filed on Feb. 12, 2010, (Attorney Docket No. ISRG 02180/US); U.S. Provisional Application No. 61/260,907, entitled “END EFFECTOR WITH REDUNDANT CLOSING MECHANISMS,” filed on Nov. 13, 2009, (Attorney Docket No. ISRG02330PROV); U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009, (Attorney Docket No. ISRG02320PROV), (Attorney Docket No. ISRG 02320/US); U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009, (Attorney Docket No. ISRG02320PROV); U.S. Provisional Application No. 61/260,915, entitled “SURGICAL TOOL WITH A TWO DEGREE OF FREEDOM WRIST,” filed on Nov. 13, 2009, (Attorney Docket No. ISRG02350PROV); and U.S. Provisional Application No. 61/260,919, entitled “MOTOR INTERFACE FOR PARALLEL DRIVE SHAFTS WITHIN AN INDEPENDENTLY ROTATING MEMBER,” filed on Nov. 13, 2009, (Attorney Docket No. ISRG02360PROV); each of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Minimally invasive surgical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. As a consequence, the average length of a hospital stay for standard surgery may be shortened significantly using minimally invasive surgical techniques. Also, patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery. 
     A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient&#39;s abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately one-half inch or less) incisions to provide entry ports for laparoscopic instruments. 
     Laparoscopic surgical instruments generally include an endoscope (e.g., laparoscope) for viewing the surgical field and tools for working at the surgical site. The working tools are typically similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an extension tube (also known as, e.g., an instrument shaft or a main shaft). The end effector can include, for example, a clamp, grasper, scissor, stapler, cautery tool, linear cutter, or needle holder. 
     To perform surgical procedures, the surgeon passes working tools through cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon views the procedure by means of a monitor that displays an image of the surgical site taken from the endoscope. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like. 
     Minimally invasive telesurgical robotic systems are being developed to increase a surgeon&#39;s dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a telesurgery system, the surgeon is often provided with an image of the surgical site at a control console. While viewing an image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console. Each of the master input devices controls the motion of a servo-mechanically actuated/articulated surgical instrument. During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of the master input devices. 
     Non-robotic linear clamping, cutting and stapling devices have been employed in many different surgical procedures. For example, such a device can be used to resect a cancerous or anomalous tissue from a gastro-intestinal tract. Unfortunately, many known surgical devices, including known linear clamping, cutting and stapling devices, have opposing jaws that may generate less than a desired clamping force, which may reduce the effectiveness of the surgical device. Devices have been developed generating higher levels of clamping forces for applicable surgical procedures (e.g., tissue stapling), however, clamping with high force jaws periodically fails. Additionally, firing of staples to seal tissue may fail. Detecting failure in clamping or firing of a staple has proven difficult in some minimally invasive surgical applications, however, since a surgeon may not have a clear view of the tissue being clamped or stapled and a tool inserted into a body is constrained by significant size and space limitations. Since a surgeon&#39;s tactile feedback in a robotic system can be somewhat limited, a surgeon may not realize when failure has occurred until after the clamping or firing procedure is complete. In light of the above, it would be desirable to enable a surgeon to detect clamping or failure at the time it occurs, so that the procedure can be suspended or modified to reduce the likelihood of tissue damage and/or to allow the surgeon to mitigate the effects of any tissue which has been damaged. Given the limitations associated with a minimally invasive surgical environment, it would be desirable to detect failure from outside the body without substantially adding to the profile of the end effector. 
     Thus, methods and system which can detect failure and indicate failure to the user, yet are compatible with the demands of minimally invasive procedures are desirable. Such tools may be beneficial in surgical applications, particularly in minimally invasive surgical applications. 
     BRIEF SUMMARY OF THE INVENTION 
     Improved systems and methods to detect and indicate clamping and/or staple firing failure are provided. The claimed methods and systems relate to detecting whether clamping of a material grasped between jaws or firing of a staple into the clamped material is likely to fail. The claimed systems and methods may detect failure in clamping or firing during the process of clamping or firing, thereby reducing the potential for tissue damage from continuing to clamp or fire a staple after failure has occurred. The claimed systems and methods are particularly useful in surgical applications involving clamping of a body tissue between two jaws of an end effector and firing of a staple into the clamped tissue. Many surgical applications require clamping of a body tissue at a clamping force sufficient for cutting, sealing and/or stapling of the clamped tissue. Since clamping and firing of a staple may require relatively higher forces than tissue manipulation, failure in clamping or firing may potentially cause damage to the delicate tissues. The present methods and systems are particularly advantageous in minimally invasive surgical applications as they indicate failure as soon as it occurs and allows for detection of failure from outside the body. While the various embodiments disclosed herein are primarily described with regard to surgical applications, these surgical applications are merely example applications, and the disclosed end effectors, tools, and methods can be used in other suitable applications, both inside and outside a human body, as well as in non-surgical applications. 
     In a first aspect, the invention provides a method of detecting failure in clamping of a material between jaws driven by a motor or detecting failure in firing of staple, the firing force being driven by an actuator, such as a motor. The method includes monitoring a drive parameter of the actuator or motor during application of a clamping or firing force and, in response to the monitored drive parameter, outputting an indication on a user interface of clamping or firing failure. Typically, an indication of clamping or firing failure occurs when the monitored drive parameter of the actuator, such as a torque output of a motor or displacement of a driving mechanism, is outside an acceptable range of drive parameters. The indication may also be indicative of a likelihood of clamping or firing failure, wherein the likelihood of failure falls within a gradient between a first and second likelihood, the first likelihood being likely failure and the second likelihood being likely success. In many embodiments, the material clamped and stapled is a body tissue, including an outer skin or internal organs, such as a bowel, stomach or lung. 
     In many embodiments, the methods and systems include monitoring a drive parameter during clamping between a first and second jaw of an end effector or during firing of a staple into clamped tissue. Often, the clamped tissue is cut after opposing sides of the tissue along the cutting line are stapled by a row of surgical staples to seal the tissue. The end effector is generally part of a minimally invasive robotic surgical system. The first and second jaw may comprise two separate jaws or a first jaw articulable against a portion of the end effector, in which case the portion of the end effector comprises the second jaw. In one aspect, the methods include clamping of a material between the first and second jaw of an end effector or firing of a staple into the clamped material, typically in response to a command from a user to clamp or fire. The system effects clamping or firing by applying a clamping force to a clamp or firing force to a staple. As the clamping or firing occurs, the system monitors the drive parameter of the actuator applying the clamping or firing force. In response to the monitored drive parameter, the system outputs an indication on a user interface of clamping or firing failure or the clamping or firing success. 
     In many embodiments, an indication of likely clamping or firing failure is provided in response to the monitored drive parameter being outside an acceptable range of desired drive parameters of the actuator, such as a range of torque outputs. Often, the acceptable range of drive parameters vary with the displacement of the actuator or motor, such that the acceptable range of drive parameters may be different depending on the configuration of the end effector. For example, the acceptable range of drive parameters at an initial displacement of the actuator or motor (as the clamp starts from an open configuration) may be different from the acceptable range of drive parameters at a final displacement (such as when the clamp is in a closed/clamped configuration). The same is true for the different initial configuration and final configuration of the firing mechanism. The system may detect the configuration of the end effector by sensing the displacement of the actuator effecting movement, or the mechanism through which the actuator effects clamping or firing. The clamping or firing is effected by the drive parameter through one or more mechanisms coupling the actuator to the end effector and/or the staple. The mechanism(s) may include a cable, a hypotube, or a leadscrew. In many embodiments, the indication of likely clamping failure is a visual indicator shown on a display of a user interface, but may also be communicated to the user by an audio signal, visual signal, or other sensory indicator. 
     In another aspect, a method or system may suspend driving of the actuator in response to an indication of failure or likely failure in clamping or firing of the staple. The methods may also include maintaining a driving parameter after an indication of failure, or maintaining a driving parameter driving clamping while suspending a force driving firing of a staple. In many embodiments, the clamping mechanism is non-backdriveable such that no input is needed to maintain the clamping force once it is applied or established. In such cases, an input may be needed to unclamp and reverse the motion of the leadscrew. The methods may include reversing a driving force so as to unclamp after outputting the indication of failure. 
     In many embodiments, the system includes an end effector, a sensor, and a user interface. A first and second jaw of the end effector are coupled to an actuator such that driving the actuator produces a clamping force so as to clamp a material between the first and second jaws. The system may also include an actuator, such as a motor, releasably coupled to a staple such that driving the actuator produces a firing force so as to fire the staple into the body tissue. The clamping and firing actuator may be a single actuator or may be separate actuators. The system may include a sensor for monitoring the drive parameters applying the clamping or firing forces to the end effector. The sensor may be a separate sensor or may be incorporated into the robotic surgical system and may also monitor a displacement of the motor or mechanism. The systems may also include a processor for comparing the monitored drive parameter with a desired drive parameter or range of parameters. The processor may also determine the range of acceptable drive parameters for a given displacement. 
     The system may comprise a first and second actuation mechanism for effecting clamping and firing, respectively. The first and second actuation mechanisms can employ different force transmission mechanisms corresponding with the force requirements for the clamping mode and the firing force mode. For example, a force used by the first jaw actuation mechanism to move the jaw from the open to the close position can include a linear force or a torque, and a force used by the second jaw actuation mechanism to fire a staple through the tissue can include a torque. In many embodiments, the first actuation mechanism includes a leadscrew-driven mechanism for use in the high force clamping mode, and the second actuation mechanism includes a second leadscrew-driven mechanism for use in the firing of the staple. Alternatively, the clamping and firing may utilize a portion of or the same mechanism. 
     For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings. Other aspects, objects and advantages of the invention will be apparent from the drawings and detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view of a minimally invasive robotic surgery system being used to perform a surgery, in accordance with many embodiments. 
         FIG.  2    is a perspective view of a surgeon&#39;s control console for a robotic surgery system, in accordance with many embodiments. 
         FIG.  3    is a perspective view of a robotic surgery system electronics cart, in accordance with many embodiments. 
         FIG.  4    diagrammatically illustrates a robotic surgery system, in accordance with many embodiments. 
         FIG.  5 A  is a front view of a patient side cart (surgical robot) of a robotic surgery system, in accordance with many embodiments. 
         FIG.  5 B  is a front view of a robotic surgery tool. 
         FIG.  6 A  is a perspective view of an end effector having an articulated jaw, in accordance with many embodiments. 
         FIG.  6 B  is a perspective view of the end effector of  FIG.  6 A  (with the articulated jaw removed to better illustrate leadscrew actuation mechanism components), in accordance with many embodiments. 
         FIGS.  7 A and  7 B  illustrate components of a leadscrew actuation mechanism, in accordance with many embodiments. 
         FIG.  8 A  illustrates components of a cable actuation mechanism, in accordance with many embodiments. 
         FIG.  8 B  is a perspective view of the end effector of  FIG.  8 A  with a portion of the articulated jaw removed to show cable actuation mechanism components disposed behind the articulated jaw, in accordance with many embodiments. 
         FIGS.  8 C through  8 F  illustrate opposite side components of the cable actuation mechanism of  FIG.  8 A . 
         FIG.  9 A  is a perspective view illustrating a cable actuation mechanism, showing a cable used to articulate the jaw towards a clamped configuration, in accordance with many embodiments. 
         FIG.  9 B  is a perspective view illustrating the cable actuation mechanism of  FIG.  9 A , showing a cable used to articulate the jaw towards an open configuration. 
         FIG.  10    is a cross-sectional view illustrating components of a leadscrew actuation mechanism, in accordance with many embodiments. 
         FIG.  11    is a simplified diagrammatic illustration of a tool assembly, in accordance with many embodiments. 
         FIG.  12    is a simplified diagrammatic illustration of a robotic tool mounted to a robotic tool manipulator, in accordance with many embodiments. 
         FIG.  13    is a diagrammatic view of a telerobotic surgical system, in accordance with many embodiments. 
         FIGS.  14 A- 14 B  illustrate the user interface assembly having an clamping failure indicator, in accordance with many embodiments. 
         FIGS.  15 A- 15 B  illustrate examples of indicators of clamping failure indicators, in accordance with many embodiments. 
         FIGS.  16 A- 16 B  illustrates exemplary motor torques during clamping as compared to a range of acceptable motor torques which vary with motor displacement, in accordance with many embodiments. 
         FIGS.  17 - 20    illustrate methods, in accordance with many embodiments. 
         FIGS.  21 - 22    illustrate flow charts utilizing methods in accordance with many embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Improved systems and methods related to clamping and/or fastener firing are provided. The present invention relates to providing an indicator of whether clamping of a given material fails during clamping. The invention may be used in systems having jaw members for clamping a material or firing of a staple into a clamped material. The claimed system and methods are particularly useful for minimally invasive surgical applications, as they allow for failure detection in constrained environments from outside the body. Such systems often include end effectors having jaws that clamp a body tissue and fire a staple into the tissue at a relatively high force. Clamping at a high clamping force allows the user to perform various procedures requiring a hard clamp. For example, a physician may require a hard clamp of body tissues before cutting, sealing or stapling of tissue. Firing of staples or other fasteners may also require use of relatively high forces to drive the staple through the body tissue. Since clamping and staple firing utilize relatively high forces applied in a confined surgical area, clamping or firing failure has the potential to damage delicate tissues. The claimed methods and systems are advantageous as they allow detection of clamping or firing failure during the clamping or firing process from outside the body without increasing the profile of the end effector. Such methods and systems allow for increased capabilities and safety for the patient while maintaining the reduced scale of the minimally invasive surgical tools. While the various embodiments disclosed herein are primarily described with regard to surgical applications, these surgical applications are merely example applications, and the disclosed systems and methods can be used in other suitable applications, both inside and outside a human body, as well as in non-surgical applications. 
     Typically, a system utilizing the claimed invention includes an end effector having two jaws for clamping a material and/or firing a staple or fastener through the clamped material. The two jaws may comprise an articulated jaw attached to an end effector, such that moving the articulated jaw towards a portion of the end effector, the second jaw being that portion of the end effector. In many embodiments, the system uses two independent mechanisms to articulate the jaws of the end effector. A first actuation mechanism provides a fast response/low force mode that varies the position of the articulated jaw between a closed (grasped) configuration and an open configuration. In many embodiments, the first actuation mechanism is back-drivable. For example, in the low force mode grasping mode the first actuation mechanism can be designed to provide 5 lbs of clamping force between the tips of the first and second jaw. A second actuation mechanism provides a high clamping force mode for clamping the body tissue between the jaws at the higher clamping force. Often, the second actuation mechanism is non-back-drivable. The second actuation mechanism converts a relatively weak force or torque (but with large displacement available) to a relatively high torque rotating the jaw of the end effector. The second actuation mechanism can be designed to provide, for example, 50 pounds of clamping force between the tips of the clamped jaws. 
     Typically, in applications using the claimed methods, a surgeon clamps the body tissue at the relatively high clamping force and once clamped, fires a series of staples through the clamped tissue thereby sealing the tissue. Periodically, the jaws may fail to clamp the tissue, potentially resulting in damage to the tissue. Clamping of the tissue may fail for a variety of reasons, including too much tissue being grasped or insufficient tissue grasped between the jaws, including interference from an adjacent tissue, such as a bone, or slippage of the tissue from between the jaws. Even if clamping is successful, firing of a staple or other fastener may fail for a variety of reasons, including a jammed staple, inconsistencies in the material, interference from another material, or slippage of the clamped material. Therefore, it would be advantageous for systems and methods that can detect when clamping or firing failure occurs during the process of clamping or firing and indicate such failure to a physician, thereby reducing the likelihood that tissue damage will result. Ways in which tissue damage can be avoided by use of the claimed methods, include: terminating the clamping or firing process or allowing the user to terminate or modify the process after failure has been indicated. The described systems and methods detect such failures and provide an indication to the user of failure or likely failure during clamping and/or staple firing into a clamped material. Clamping may be considered successful when in the clamped position, the distance between the jaws are sufficient for performing a therapy, such as firing a staple through the clamped tissue. This distance may vary according to various factors, including the type of tissue, type of treatment, or the dimensions of a staple to be fired through the clamped tissue. In one aspect, the claimed methods and systems detect failure by monitoring a drive parameter of an actuator or motor that drives the clamping and/or staple firing. In a preferred embodiment, the motor provides a drive parameter or force output, such as a torque, to a mechanism so as to effect clamping and/or firing of a staple with the end effector. The system may determine whether the drive parameter is within an acceptable range of desired drive parameters. The acceptable range of drive parameters may vary according to the displacement of the motor or the mechanism effecting movement. Typically, if clamping or firing fails the force output of the driving motor drops below a minimum acceptable, such as from an absence of material between clamping jaws, or the force output may spike above a maximum acceptable force, such as from clamping on a bone or jamming of the mechanism. Continuing driving of the motor in either case may result in damage to surrounding materials or tissue. By monitoring the force output of the driving motor during clamping of the material and/or firing into the tissue, the claimed methods and systems detect failure or likely failure during clamping or firing and output an indication of such failure or likely failure to the user. Additionally, the system and methods may automatically terminate the clamping or firing or wait for further input from the user after providing an indication of failure. Ideally, the methods include monitoring a drive parameter during clamping or staple firing, and providing an indication of the likelihood of clamping or firing failure in response to the monitored drive parameter. 
     Minimally Invasive Robotic Surgery 
     Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,  FIG.  1    is a plan view illustration of an embodiment of the present invention.  FIG.  1    illustrates a Minimally Invasive Robotic Surgical (MIRS) system  10 , typically used for performing a minimally invasive diagnostic or surgical procedure on a Patient  12  who is lying down on an Operating table  14 . The system can include a Surgeon&#39;s Console  16  for use by a Surgeon  18  during the procedure. One or more Assistants  20  may also participate in the procedure. The MIRS system  10  can further include a Patient Side Cart  22  (surgical robot), and an Electronics Cart  24 . The Patient Side Cart  22  can manipulate at least one removably coupled tool assembly  26  (hereinafter simply referred to as a “tool”) through a minimally invasive incision in the body of the Patient  12  while the Surgeon  18  views the surgical site through the Console  16 . Tool assembly  26  includes end effector  25 , the end effector having jaws for clamping the tissue and a mechanism for firing a staple through the clamped tissue. An image of the surgical site can be obtained by an endoscope  28 , such as a stereoscopic endoscope, which can be manipulated by the Patient Side Cart  22  so as to orient the endoscope  28 . The Electronics Cart  24  can be used to process the images of the surgical site for subsequent display to the Surgeon  18  through the Surgeon&#39;s Console  16 . Electronics Cart  24  includes a Processor  27  for monitoring the drive parameter provided by the motor output to the end effector. Processor  27  may monitor the drive parameter by comparing the drive parameter to an acceptable range of drive parameters. As the acceptable range of drive parameters may vary with the displacement of the motor or the mechanism effecting movement of the end effector, the Processor  27  may also receive displacement data as to the displacement of the motor or the end effector mechanism during clamping and/or firing such that Processor  27  compares the monitored drive parameters against a range of acceptable drive parameters for any given displacement. The displacement data may be measured directly or may be determined from positional data, or derivatives thereof, obtained by the robotic system, such as a robotic patient-side manipulator (PSM) system, for example, described in U.S. Patent Application Publication No 2007/0005045, the entire contents of which are incorporated herein by reference. In response to the monitored drive parameter, Processor  27  may output a clamping failure indication to a user interface. The system  10  then communicates an indicator of the prediction to the physician on the Surgeon&#39;s Console  16  so as to communicate to the surgeon whether clamping or firing has failed. 
       FIG.  2    is a perspective view of the Surgeon&#39;s Console  16 . The Surgeon&#39;s Console  16  includes a left eye display  32  and a right eye display  34  for presenting the Surgeon  18  with a coordinated stereo view of the surgical site that enables depth perception. The Console  16  further includes one or more input control devices  36 , which in turn cause the Patient Side Cart  22  (shown in  FIG.  1   ) to manipulate one or more tools. The input control devices  36  will provide the same degrees of freedom as their associated tools  26  (shown in  FIG.  1   ) so as to provide the Surgeon with telepresence, or the perception that the input control devices  36  are integral with the tools  26  so that the Surgeon has a strong sense of directly controlling the tools  26 . To this end, position, force, and tactile feedback sensors (not shown) may be employed to transmit position, force, and tactile sensations from the tools  26  back to the Surgeon&#39;s hands through the input control devices  36 . 
     The Surgeon&#39;s Console  16  is usually located in the same room as the patient so that the Surgeon may directly monitor the procedure, be physically present if necessary, and speak to an Assistant directly rather than over the telephone or other communication medium. However, the Surgeon can be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures (i.e., operating from outside the sterile field). 
       FIG.  3    is a perspective view of the Electronics Cart  24 . The Electronics Cart  24  can be coupled with the endoscope  28  and can include Processor  27  to monitor the drive parameter and to determine an indication of clamping failure in response to the monitored drive parameter. Processor  27  may also process captured images for subsequent display, such as to a Surgeon on the Surgeon&#39;s Console, or on any other suitable display located locally and/or remotely. 
       FIG.  4    diagrammatically illustrates a robotic surgery system  50  (such as MIRS system  10  of  FIG.  1   ), in which the Processor  58  and Display  60  are depicted separately from Electronics Cart  56  and Surgeon&#39;s Console  52 . As discussed above, a Surgeon&#39;s Console  52  (such as Surgeon&#39;s Console  16  in  FIG.  1   ) can be used by a Surgeon to control a Patient Side Cart (Surgical Robot)  54  (such as patent Side Cart  22  in  FIG.  1   ) during a minimally invasive procedure. In preparation for firing a staple to seal a body tissue, the Surgeon can command the tool of the Patient Side Cart  54  to clamp between jaw members of an end effector. In response to this command, Processor  58  can command the system to begin driving the motor to engage a mechanism that begins moving the jaws together and increase a clamping force to a desired clamping force. As the jaws begin moving together and the clamping force increases, the Processor  58  continuously monitors a drive parameter of the motor and compares the drive parameter to an acceptable range of drive parameters as the motor drives the jaws to clamp at a desired clamping force. If at any point during clamping, the drive parameter exceeds or drops below an acceptable drive parameter, Processor  58  may output the indication of clamping failure on the user interface. In response to detection of clamping failure, Processor  58  may also command additional functions, such as suspending driving of the motor, preventing firing of the staple, maintaining the clamping force at the point of detected clamping failure, waiting for user input, and unclamping the tissue. Similarly, the Processor  58  continuously monitors the drive parameter during firing of a staple through successfully clamped tissue. In response to the drive parameter falling outside the acceptable range of desired drive parameters, Processor  58  may output a failure indication on the user interface. In response to detected firing failure, Processor  58  may command other functions, such as terminating firing, suspending driving of the motor, maintaining clamping of the tissue while preventing firing, or waiting for user input. 
     One of skill in the art would appreciate that an indication of clamping failure may include an indication of how likely clamping failure may be. For example, the Processor  58  may output an indication of clamping failure indicating the likelihood of clamping failure from a 0% chance of failure to a 100% chance of failure, thus allowing the user to adjust or terminate the procedure before actual failure occurs based on an increase in the likelihood of failure as indicated by the failure indication. In some embodiments, if the monitored drive parameter is within the acceptable range of drive parameters, then a failure indicator that express a likelihood of failure may express a likelihood of failure that falls within a range of 0 to 49%. In another embodiment, this range may be expressed as a gradient, including a non-numerical gradient, such as a color gradient. Depending on the likelihood of failure as communicated by the failure indicator, the Surgeon may then safely proceed with clamping of the body tissue or may abort clamping and reposition the jaws until Display  60  indicates a higher likelihood of clamping or firing success. 
       FIGS.  5 A and  5 B  show a Patient Side Cart  22  and a surgical tool  62 , respectively. The surgical tool  62 , one of the surgical tools  26 , is an example of an end effector having a set of jaw members for clamping a tissue and firing a staple into the clamped tissue. The Patient Side Cart  22  shown provides for the manipulation of three surgical tools  26  and an imaging device  28 , such as a stereoscopic endoscope used for the capture of images of the site of the procedure. Manipulation is provided by robotic mechanisms having a number of robotic joints. The imaging device  28  and the surgical tools  26  can be positioned and manipulated through incisions in the patient so that a kinematic remote center is maintained at the incision so as to minimize the size of the incision. Images of the surgical site can include images of the distal ends of the surgical tools  26  when they are positioned within the field-of-view of the imaging device  28 . 
     Tissue Clamping and Staple Firing with Independent Actuation Mechanisms 
     In many embodiments, two independent actuation mechanisms are used to control the articulation of an articulated jaw of an end effector. A first actuation mechanism can be used to provide a high force clamping mode, and a second actuation mechanism can be used to provide a high force firing mode. In many embodiments, the first and second actuation mechanism used to provide the high clamping force and high firing force is non-back-drivable. The first and second actuation mechanisms may comprise a first and second leadscrew. Using independent actuation mechanisms may be beneficial in some surgical applications, for example, electrocautery sealing, stapling, etc., that may require different forces for different functions during the same procedure. 
     In many embodiments, actuation of the jaws in the high clamping force mode is provided by a leadscrew actuation mechanism that includes a leadscrew driven cam. The driven cam interfaces with a mating cam surface on the articulated jaw so as to hold the articulated jaw in a closed (clamped) configuration when the leadscrew driven cam is at a first end of its range of motion. In addition, the driven cam does not constrain motion of the articulated jaw when the leadscrew driven cam is at a second end (opposite end) of its range of motion. In other words, the mating cam surfaces are arranged such that motion of the leadscrew driven cam in one direction will cause the articulated jaw to close, and motion of the leadscrew driven cam in the reverse direction will allow (but not force) the articulated jaw to open to a limit provided by the cam surfaces. Often, the leadscrew actuation mechanism is non-back-drivable. In many embodiments, the position of the jaw members of the end effector can be determined by the position of the cable actuation mechanism, or if driven by a leadscrew, the position of the leadscrew. The system may include a dual drive motor having a drive for effecting clamping at a clamping force and a drive for effecting firing a staple at a firing force. The motor may utilize an existing motor or drive, or utilize an additional drive or motor, to effect firing of the staple. The claimed methods and systems monitor the drive parameter of whichever motor, or motors, which are driving the clamping or firing. Additionally, terminating or stopping driving of the motor when failure is detected may also comprise continuing driving of another drive or motor effecting another function. For example, if firing failure is indicated, the system may stop driving the firing force, while still maintaining the driving of the clamping force and wait for a user to unclamp the tissue. 
       FIG.  6 A  is a perspective view of an end effector  70  having a jaw  72  articulated by two independent actuation mechanisms, in accordance with many embodiments. The end effector  70  includes an end effector base  74 , the articulated jaw  72 , and a detachable stationary jaw  76 , which holds the staples. The end effector  70  is actuated via a first drive shaft  78 , a second drive shaft  80 , and two actuation cables (not shown). The first drive shaft  78  rotates a leadscrew  82  of a leadscrew actuation mechanism, the leadscrew  82  located within the stationary jaw  76 . The second drive shaft  80  rotates another leadscrew (not shown) of the detachable stationary jaw  76 . 
     In many embodiments, the first drive shaft  78  and/or the second drive shaft  80  are driven by drive features located in a proximal tool chassis to which the end effector  70  is coupled with via an instrument shaft. In many embodiments, the proximal tool chassis is configured to be releasably mountable to a robotic tool manipulator. In many embodiments, the first drive shaft  78  and the second drive shaft  80  are actuated via respective drive features located in the proximal tool chassis. In many embodiments, such drive features are driven by motors that are located in the proximal tool chassis. 
       FIG.  6 B  is a perspective view of the end effector  70  of  FIG.  6 A  (with the articulated jaw  72  removed to better illustrate components of the leadscrew actuation mechanism), in accordance with many embodiments. The leadscrew  82  is mounted for rotation relative to the end effector base  74 . A leadscrew driven cam  84  is coupled with the leadscrew  82  so that selective rotation of the leadscrew  82  can be used to selectively translate the leadscrew driven cam  84  along a cam slot  86  in the end effector base  74 . The end effector  70  includes a pivot pin  88  that is used to rotationally couple the articulated jaw  72  with the end effector base  74 . 
       FIGS.  7 A  through- 10  illustrate the actuation mechanisms by which an end effector clamps a body tissue between its jaws clamping mode and fires a staple into the clamped tissue. 
       FIGS.  7 A and  7 B  illustrate the leadscrew actuation mechanism of  FIGS.  6 A and  6 B . The leadscrew  82  has a distal journal surface  96  and a proximal journal surface that interfaces with a proximal bearing  98 . In many embodiments, the distal journal surface  96  is received within a cylindrical receptacle located at the distal end of the cam slot  86 . Such a distal support for the leadscrew  82  can be configured to keep the leadscrew  82  from swinging excessively, and with relatively large clearance(s) between the distal journal surface  96  and the cylindrical receptacle. The proximal bearing  98  is supported by the end effector base  74  so as to support the proximal end of the leadscrew  82 . The proximal bearing  98  can be a ball bearing, which may help to reduce friction and wear. A distal bearing (not shown) can be supported by the end effector base  74  so as to support the distal end of the leadscrew  82 , and the distal bearing can be a ball bearing. The leadscrew driven cam  84  includes a threaded bore configured to mate with the external threads of the leadscrew  82 . The leadscrew driven cam  84  includes top and bottom surfaces configured to interact with corresponding top and bottom surfaces of the cam slot  86 . The interaction between leadscrew driven cam  84  and the cam slot  86  prevents the leadscrew driven cam  84  from rotating relative to the cam slot  86 , which causes the leadscrew driven cam  84  to translate along the cam slot  86  in response to rotation of the leadscrew. 
     The articulated jaw  72  includes mating cam surfaces  94  that are configured so that the position of the leadscrew driven cam  84  along the cam slot  86  determines the extent to which the rotational motion of the articulated jaw  72  around the pivot pin  88  is constrained by the leadscrew driven cam  84 . The articulated jaw  72  includes a first proximal side  100  and a second proximal side  102  that are separated by a central slot. The first and second proximal sides are disposed on opposing sides of the end effector base  74  when the articulated jaw  72  is coupled with the end effector base  74  via the pivot pin  88 . Each of the first and second proximal sides  100 ,  102  includes a recessed area defining a mating cam surface  94  and providing clearance between the leadscrew driven cam  84  and the proximal sides  100 ,  102 . When the leadscrew driven cam  84  is positioned at or near the proximal end of the cam slot  86  (near its position illustrated in  FIGS.  7 A and  7 B ), contact between the leadscrew driven cam  84  and the mating cam surfaces  94  of the articulated jaw  72  hold the articulated jaw in a clamped configuration. When the leadscrew driven cam  84  is positioned at the distal end of the cam slot  86 , the rotational position of the articulated jaw around the pivot pin  88  is unconstrained by the leadscrew driven cam  84  for a range of rotational positions between a clamped configuration (where there is a gap between the leadscrew driven cam  84  and the mating cam surfaces  94  of the articulated jaw  72 ) and an open configuration (where there may or may not be a gap between the leadscrew driven cam  84  and the mating cam surfaces  94  of the articulated jaw  72 ). For positions of the leadscrew driven cam  84  in between the proximal and distal ends of the cam slot  86 , the range of unconstrained motion can vary according to the cam surfaces used. 
     The use of a recess in each of the proximal sides  100 ,  102  to define the mating cam surfaces  94  of the articulated jaw  72  provides a number of benefits. For example, the use of recesses as opposed to traverse slots that extend through the proximal sides provides a continuous outside surface to the proximal sides  100 ,  102  of the articulated jaw, which is less likely to snag on patient tissue than would a traverse slot opening. The absence of traverse slots also helps to stiffen the proximal sides  100 ,  102  as compared to proximal sides with traverse slots, and therefore provides increased clamping stiffness. Such proximal sides  100 ,  102  may have increased stiffness in two planes, which may help maintain alignment of the articulated jaw  72  in the presences of external forces. Such increased stiffness in two planes may be beneficial in some surgical applications, for example, in tissue stapling where it is beneficial to maintain alignment between the staples and anvil pockets that form the staples. Further, the use of recesses instead of traverse slots also provides an actuation mechanism that is less likely to be jammed by extraneous material as compared to one having proximal sides with open traverse slots. 
     The leadscrew actuation mechanism can be configured to provide a desired clamping force between the articulated jaw and an opposing jaw of the end effector to facilitate cutting or sealing of the tissue. For example, in many embodiments, the leadscrew actuation mechanism is configured to provide at least 20 lbs of clamping force at the tip of the articulated jaw  72  (approximately 2 inches from the pivot pin  88 ). In many embodiments, the leadscrew actuation mechanism is configured to provide at least 50 lbs of clamping force at the tip of the articulated jaw  72 . In many embodiments, to produce 50 lbs of clamping force at the tip of the articulated jaw  72 , the input torque to the leadscrew  82  is approximately 0.2 N m and the leadscrew  82  has 29 turns. The system may detect the displacement of the motor, of the clamping or firing mechanism or the configuration of the end effector by sensing the displacement of the leadscrew. For example, in many embodiments, the system is calibrated before starting the procedure so as to determine the range of motion of both the clamping and the firing mechanism and the displacement of the leadscrew within that range of motion. Such calibration allows the system to determine the configuration of the end effector or the displacement of the mechanism solely from the displacement of the leadscrew. 
     The leadscrew actuation mechanism can be fabricated using available materials and components. For example, many components of the leadscrew actuation mechanism can be fabricated from an available stainless steel(s). The leadscrew driven cam  84  can be coated (e.g., TiN) to reduce friction against the surfaces it rubs against (e.g., leadscrew  82 ; end effector base  74 ; proximal sides  100 ,  102  of the articulated jaw  72 ). Stranded cables can be used to drive the first actuation mechanism. 
       FIGS.  8 A through  8 F  illustrate components of a cable actuation mechanism  110 , in accordance with many embodiments. As described above, the leadscrew driven cam  84  can be positioned at the distal end of the cam slot  86  (i.e., near the pivot pin  88 ). For such a distal position of the leadscrew driven cam  84 , as discussed above, the rotational position of the articulated jaw  72  about the pivot pin  88  is unconstrained for a range of rotational positions of the articulated jaw  72 . Accordingly, the rotational position of the articulated jaw  72  about the pivot pin  88  can be controlled by the cable actuation mechanism  110 . The cable actuation mechanism  110  is operable to vary the rotational position of the articulated jaw between the clamped configuration and the open configuration. The cable actuation mechanism  110  includes a pair of pull cables  112 ,  114 . The cable actuation mechanism  110  also includes a first linkage  116  that is used to rotate the articulated jaw  72  about the pivot pin  88  towards the clamped configuration, and an analogous second linkage  118  that is used to rotate the articulated jaw  72  about the pivot pin  88  towards the open configuration. The first linkage  116  (shown in  FIGS.  8 A and  8 B ) includes a rotary link  120  that is mounted for rotation relative to the end effector base  74  via a pivot pin  122 . A connecting link  124  couples the rotary link  120  to the articulated jaw  72  via a pivot pin  126  and a pivot pin  128 . The first linkage  116  is articulated via a pulling motion of the pull cable  112 . In operation, a pulling motion of the pull cable  112  rotates the rotary link  120  in a clockwise direction about the pivot pin  122 . The resulting motion of the connecting link  124  rotates the articulated jaw  72  in a counter-clockwise direction about the pivot pin  88  towards the clamped configuration. 
     The second linkage  118  (shown in  FIGS.  8 C through  8 F ) of the cable actuation mechanism  110  includes analogous components to the first linkage  116 , for example, a rotary link  130  mounted for rotation relative to the end effector base  74  via a pivot pin  132 , and a connecting link  134  that couples the rotary link  130  to the articulated jaw  72  via two pivot pins  136 ,  138 . The second linkage  118  is articulated via a pulling motion of the pull cable  114 . The second linkage  118  is configured such that a pulling motion of the pull cable  114  rotates the articulated jaw  72  about the pivot pin  88  towards the open configuration. In many embodiments, the pivot pin  136  between the connecting link  134  and the rotary link  130  of the second linkage  118  is 180 degrees out of phase with the pivot pin  126  between the connecting link  124  and the rotary link  120  of the first linkage  116 . Coordinated pulling and extension of the pull cables  112 ,  114  of the cable actuation mechanism  110  is used to articulate the articulated jaw  72  between the open and clamped configurations. In order to best provide equal and opposite cable motion (and thereby maintain cable tension in a capstan-driven system described below), a common rotational axis for the pivot pins  122 ,  132  is configured to lie on a plane that contains the rotational axes for pivot pins  128 ,  138  when the articulated jaw  72  is closed (or nearly closed) and again when the when the articulated jaw  72  is open (or nearly open). The connecting links  124 ,  134  are assembled symmetrically opposite about this same plane for the first and second linkages  116 ,  118 . The distance between the pivot pins  122 ,  126  and between the pivot pins  132 ,  136  is the same for both the first and second linkages  116 ,  118 , and the distance between the pivot pins  126 ,  128  and between the pivot pins  136 ,  138  is the same for both the first and second linkages  116 ,  118 . 
       FIGS.  9 A and  9 B  illustrate an articulation of the articulated jaw  72  via another cable actuation mechanism  140 , in accordance with many embodiments. In embodiment  140  of the cable actuation mechanism, a first pull cable  142  and a second pull cable  144  are directly coupled with the proximal end of the articulated jaw  72 . The first pull cable  142  wraps around a first pulley  146  so that a pulling motion of the first pull cable  142  rotates the articulated jaw  72  about the pivot pin  88  towards the clamped configuration. The second pull cable  144  wraps around a second pulley  148  so that a pulling motion of the second pull cable  144  rotates the articulated jaw  72  about the pivot pin  88  towards the open configuration. Accordingly, coordinated pulling and extension of the first and second pull cables of the cable actuation mechanism  140  is used to articulate the articulated jaw  72  between the open and clamped configurations. In order to best provide equal and opposite cable motion (and thereby maintain cable tension in the capstan-driven system described below), the radius of the arc prescribed by cable  142  about the pivot  88  is substantially the same as the radius prescribed by cable  144  about the pivot  88 . 
     Although the mechanisms may comprise leadscrews, cable or hypotubes, alternate mechanisms can be used to effect clamping or staple firing. For example, an actuation mechanism comprising push/pull rods or springs can be used. 
       FIG.  10    is a cross-sectional view illustrating components of the above discussed leadscrew actuation mechanism. The illustrated components include the leadscrew  82 , the leadscrew driven cam  84 , the cam slot  86  in the end effector base  74 , the distal journal surface  96 , the cylindrical receptacle  154  in the end effector base, and the proximal bearing  98  supported by the end effector base  74 . 
       FIG.  11    is a simplified diagrammatic illustration of a tool assembly  170 , in accordance with many embodiments. The tool assembly  170  includes a proximal actuation mechanism  172 , an elongate shaft  174  having a proximal end and a distal end, a tool body  176  disposed at the distal end of the shaft, a jaw  178  movable relative to the tool body  176  between a clamped configuration and an open configuration, a first actuation mechanism coupled with the jaw, and a second actuation mechanism coupled with the jaw. The first actuation mechanism is operable to vary the position of the jaw relative to the tool body between the clamped configuration and the open configuration. The second actuation mechanism has a first configuration where the jaw is held in the clamped configuration and a second configuration where the position of the jaw relative to the tool body is unconstrained by the second actuation mechanism. The first actuation mechanism is operatively coupled with the proximal actuation mechanism. In many embodiments, the first actuation mechanism comprises a pair of pull cables that are actuated by the proximal actuation mechanism. The second actuation mechanism is operatively coupled with the proximal actuation mechanism. In many embodiments, the second actuation mechanism includes a leadscrew driven cam located in the tool body that is driven by the proximal actuation mechanism via a drive shaft extending through the elongate shaft  174  from the proximal actuation mechanism. 
     The tool assembly  170  can be configured for use in a variety of applications. For example, the tool assembly  170  can be configured as a hand held device with manual and/or automated actuation used in the proximal actuation mechanism. The tool assembly  170  can also be configured for use in surgical applications, for example, electrocautery sealing, stapling, etc. The tool assembly  170  can have applications beyond minimally invasive robotic surgery, for example, non-robotic minimally invasive surgery, non-minimally invasive robotic surgery, non-robotic non-minimally invasive surgery, as well as other applications where the use of the disclosed redundant jaw actuation would be beneficial. 
     Redundant jaw actuation can be used to articulate a jaw of a robotic tool end effector. For example,  FIG.  12    schematically illustrates a robotic tool  180  employing redundant jaw actuation. The robotic tool  180  includes a proximal tool chassis  182 , a drive motor  184 , an instrument shaft  186 , a distal end effector  188 , a first actuation mechanism portion  190 , and a second actuation mechanism  192 . The distal end effector  188  comprises an articulated jaw  194 . The proximal tool chassis  182  is releasably mountable to a robotic tool manipulator  196  having a first drive  198 , and a first actuation mechanism portion  200  that operatively couples with the first actuation mechanism portion  190  of the robotic tool  180  when the proximal tool chassis  182  is mounted to the robotic tool manipulator  196 . The instrument shaft  186  has a proximal end adjacent the tool chassis  182 , and a distal end adjacent the end effector  188 . The first actuation mechanism (comprising portion  200  and portion  190 ) couples the first drive  198  to the articulated jaw  194  when the tool chassis  182  is mounted to the tool manipulator  196  so as to articulate the end effector  188  between an open configuration and a clamped configuration. The second actuation mechanism  192  couples the drive motor  184  to the articulated jaw  194  so as to apply a firing force to a staple so as to fire the staple from the end effector through the tissue clamped within the jaws of the end effector. The first actuation mechanism can be a leadscrew-driven mechanism that provides relatively high forces so as to fire the staple through the tissue. The second actuation mechanism can include a drive shaft that couples the drive motor  184  with a leadscrew actuation mechanism, for example, an above discussed leadscrew actuation mechanism that provides the high clamping force mode. System  180  includes Sensor  193  for monitoring the drive parameters of the first drive  198  and the drive motor  184  during clamping and firing, respectively. Sensor  193  may also detect the displacement of the first drive and the drive motor so as to determine the acceptable range of desired drive parameters according to a given displacement of the motor or configuration of the end effector. The configurations of the end effector in a clamping mode may include an open configuration, a close/clamped configuration and any configuration therebetween. The configurations of the end effector in the firing mode may include a pre-firing configuration in which one or more staples are disposed within the end effector and releasably coupled with the drive motor  184  through a mechanism and a post-firing configuration where one or more staples have been fired through the tissue, and typically bent so as to seal the tissue, the staple having been released from the end effector. The configurations of the end effector may also include any configuration in between the pre-firing and post-firing mode. By detecting the displacement of the first drive or drive motor, the sensor can determine a given configuration of the end effector in either mode, so as to more accurately determine the acceptable range of driving parameters and predict failure of clamping or firing. 
       FIG.  13    is a diagrammatic view of a telerobotic surgical system which incorporates an embodiment of the present invention. In the example of  FIG.  13   , a physician inputs a command to the system to clamp a tissue or fire a staple. In response to the user command, the system begins driving the motor  210  so as to drive clamping or firing through the clamping and/or firing mechanism  240 . As mechanism  240  effects clamping or firing, Processor  220  monitors a drive parameter, such a torque output, of Motor  210 . Monitoring may comprise comparing the torque output to an acceptable range of torque outputs for a given displacement of the motor or mechanism. The Processor  220  may be coupled to any or all of the Motor  210 , the Mechanism  240  or a Sensor  230  for detecting a displacement of the motor or mechanism during the clamping or firing. In response to the monitored drive parameter falling outside an acceptable range of torque outputs (or displacements of the driving mechanism), Processor  220  outputs a Failure Indication  250  on Display  60  of the user interface, indicating that clamping or firing has failed, or a likelihood of failure. Typically, Display  60  includes images of the end effector during clamping or firing. 
       FIGS.  14 A- 14 B  illustrate two examples of failure indicator  250  that may appear on Display  60  of System  10 . Typically, the user interface Display  60  images and/or visual representations of the surgical tool end effectors during the surgery in addition to the indicators of clamping or fairing failure. The failure indicator may be superimposed over the images on the user interface display during the surgical procedure so as to seamlessly incorporate the features of the claimed invention into the surgical procedure. Preferably, the failure indicator only appears when the Surgeon has commanded System  10  to clamp or fire a staple into a clamped tissue. By monitoring the drive parameter, System  10  provides an indication of failure during the procedure.  FIG.  14 A  depicts Display  60  with a clamping failure indicator  250  superimposed on the lower right area of the screen, wherein the failure indicator  250  indicates that clamping success is likely and that the system is proceeding to clamp.  FIG.  15 B  depicts Display  60  with failure indicator  250  superimposed on the lower right area of the screen, wherein the indicator indicates that clamping will likely fail. Failure indicator  250  is output in response to the monitored drive parameter driving the clamping being outside the predetermined range of acceptable drive parameters. 
       FIG.  15 A- 15 B  illustrate additional examples of the clamping prediction indicator  250 .  FIG.  15 A  depicts an example of a failure indicator showing a likelihood of clamping failure as a gradient, where in this example, the likelihood is expressed as a percentage of chance. For example, the further outside the range of predetermined drive parameters the actual monitored drive parameter is, the more likely clamping failure will be. For example, in one embodiment, if the actual monitored driving torque is within 5% of a predetermined target driving torque, the system will display an indicator of 90% likelihood of clamping success. As the monitored driving torque further diverges from the target driving torque, the likelihood decreases in a monotonic relationship, such as from 90% down to a 0% likelihood of clamping. Alternatively, the driving parameter may be the displacement of the driving mechanism. In such an embodiment, the system may monitor the displacement of the driving mechanism and indicate clamping or firing failure when the displacement is outside a predetermined range of acceptable displacements.  FIG.  15 B  depicts an embodiment having an indicator which toggles between two settings. When the light of the indicator is lit, likely firing failure is indicated, otherwise firing failure is not indicated. 
       FIGS.  16 A- 16 B  illustrate graphs of a monitored drive parameter in relation to an acceptable range of desired drive parameters, in accordance with many embodiments of the invention. This embodiment illustrates that the system may provide an indication of clamping and/or firing failure simply from monitoring the torque of the motor as it drives the clamping or firing of the system. As shown, the predetermined range of torques may vary in relation to the displacement of the motor as it effects movement of the end effector. The displacement (s) of the motor may be correlated by the system to a position of the end effector during the clamping process. For example, during clamping, as the displacement of the motor moves from s i  to s f , the jaws of the end effector move from an open configuration to a closed (clamped) configuration. Similarly, the motor displacement may be used to track the position or configuration of the end effector during firing of a staple into the clamped tissue. In many embodiments, before performing a procedure, the system calibrates the jaws of the end effector from a first to a second configuration, such as calibrating jaws from an open position to a closed position, so as to correlate the displacement of the motor with the configuration of the end effector. 
       FIG.  16 A  illustrates a predetermined range of acceptable driving torques (t) which vary with motor displacement (s). The range is delimited by two functions, an upper boundary t upper  and a lower boundary t lower . The system outputs an indication of clamping failure in response to the monitored driving torque T as compared to the predetermined range of acceptable driving torques. If the displacement of the motor reaches s f  and the system has not indicated likely clamping or firing failure, the system may provide an indication of successful clamping or firing. In this example, the graph depicts the acceptable range of torques and the monitored driving torque during clamping or firing as T 1 . As shown, during the clamping or firing, T 1  remains within the acceptable range of driving torques, thus the system would output an indication that clamping or firing is likely successful (which may include a lack of an indication of failure). 
       FIG.  16 B  illustrates a similar predetermined range of acceptable driving torques (t) and two separate driving torques, T 2  and T 3  (occurring at different times). As shown, T 2  falls below the lower boundary, t lower , of the acceptable range of torques. This may occur where the tissue has slipped out of the jaws of the end effector and less torque is required to close the jaws since there is no tissue between the jaws. In such case, the system would output an indication of likely clamping failure at Failure Point F 2 , at which point the system may suspend driving of the clamping to prevent any possible tissue damage from continuing to apply the clamping force after failure occurs. Failure may also occur if the driving torque exceeds the upper boundary of the range of acceptable torques, as shown by monitored torque T 3 . This may occur where jaws have clamped onto a bone and an excessive amount of torque is required to reach the closed/clamped configuration, which may potentially cause tissue damage to the bone or surrounding tissue. In this example, the monitored torque exceeds t upper  at Failure Point F 3 , at which point the system may suspend driving of the clamping or firing to reduce the likelihood of tissue damage. In response to detection of failure, the system may suspend driving of the drive parameter or reverse the driving force to unclamp the tissue, in addition to providing an indication of failure. 
       FIGS.  17 - 19    graphically illustrate embodiments of the claimed methods.  FIG.  17    is a simplified representation of exemplary method  300 . Method  300  includes a step  302  of monitoring a drive parameter of a motor driving a tool to clamp and a step  304  of outputting an indication on a user interface of a likelihood of clamping failure during clamping in response to the monitored drive parameter.  FIG.  18    is a simplified representation of exemplary method  304 . Method  304  includes a step  305  of monitoring a drive parameter of a motor driving a tool to fire a staple into a clamped material and a step  307  of outputting an indication on a user interface of a likelihood of firing failure during firing in response to the monitored drive parameter.  FIG.  19    is a simplified representation of a method  310  which further includes the step  312  of driving a motor to clamp a tissue in response to a user input to clamp, a step  314  of monitoring a drive parameter of the motor during clamping of the tissue, a step  316  of outputting an indication of a likelihood of clamping failure during clamping in response to the monitored drive parameter, and a step  318  of suspending driving of the motor if there is an indication of likely failure or continuing driving of the motor if there is no indication of likely failure.  FIG.  20    is a simplified representation of a method  320  which includes step  322  of driving a motor to clamp or fire a staple into a clamped material in response to a user input, step  324  of monitoring a drive parameter during clamping or firing, step  326  of outputting an indication on a user interface of the likelihood of clamping or firing failure during clamping or firing. If there is no indication of likely failure, then the method of  320  further includes step  328  of continuing driving the motor to clamp or fire and step  330  of outputting a message of success when clamping or firing complete. If there is an indication of likely failure, then the method of  320  further includes step  332  of suspending driving of the motor in response to the indication and step  334  of outputting an indication that the driving parameter has been suspended. 
       FIGS.  21 - 22    depict flowcharts illustrating embodiments of the claimed methods.  FIG.  21    is a flow chart showing an embodiment of the claimed method as applied to clamping as it would be incorporated into a minimally invasive robotic surgical system.  FIG.  22    is a flow chart showing an embodiment of the claimed method as applied to firing of a staple into clamped tissue as it would be incorporated into the robotic surgical system of  FIG.  20   . The described robotic system may require user input to command the system to clamp and/or firing the staple into the clamped tissue. 
     It is understood that the examples and embodiments described herein are for illustrative purposes and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims. Numerous different combinations are possible, and such combinations are considered to be part of the present invention.