Source: http://www.freepatentsonline.com/8989903.html
Timestamp: 2019-04-22 00:15:10+00:00

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Methods and systems for indicating a clamping prediction - Intuitive Surgical Operations, Inc.
End effectors with closing mechanisms, and related tools and methods to facilitate clamping, are provided. An example surgical tool comprises a first and second jaw movable between a closed grasped or clamped configuration and an open configuration. The tool further comprises a soft grip mode for grasping the tissue at a first force during which a separation parameter between the jaws is measured, and a therapeutic clamping mode in which the jaws clamp on the body tissue at a force greater than the grasping force. The methods comprise grasping the body tissue between jaw members, measuring the separation parameter between jaws, indicating on a user interface the separation parameter for comparison to a desired separation parameter, and then releasing the body tissue for repositioning or therapeutically clamping the body tissue in response to the separation parameter indication.
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The present application is a non-provisional of, and claims the benefit of U.S. Provisional Patent Application No. 61/443,159, filed Feb. 15, 2011, the entire contents of which are incorporated herein by reference.
The present application is related to U.S. application Ser. No. 12/705,418 entitled “Cut and Seal Instrument,” filed on Feb. 12, 2010; U.S. Provisional Application No. 61/260,907, entitled “END EFFECTOR WITH REDUNDANT CLOSING MECHANISMS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,915, entitled “SURGICAL TOOL WITH A TWO DEGREE OF FREEDOM WRIST,” filed on Nov. 13, 2009; 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; each of which is incorporated herein by reference in its entirety.
1. A method comprising: measuring a grasping separation parameter between two jaws grasping a material with a grasping force; and outputting an indication on a user interface in response to the measured separation parameter, wherein the indication indicates a predicted success or failure of clamping the grasped material between the two jaws at a desired clamping force, wherein the clamping force is a range of clamping forces greater than the grasping force.
2. The method of claim 1, wherein the method further comprises: determining successful clamping of the tissue; and outputting an indicator of elapsed time on the user interface after a determination of successful clamping.
3. The method of claim 2, wherein the method further comprises: outputting an indicator that it is safe to proceed with stapling of the successfully clamped tissue after a pre-determined period of time after successful clamping.
4. The method of claim 1, wherein the method is non-surgical in nature and wherein the material comprises a compliant material.
5. The method of claim 1, further comprising applying the grasping force in response to a measurement grasping force command.
6. The method of claim 1, wherein the material comprises a tissue.
7. The method of claim 6, wherein the tissue comprises a skin on the outside of a body of a patient.
8. The method of claim 6, wherein the indication of success is output in response to a determination that a clamped jaw separation will be within a desired range of clamped jaw separations when clamping the grasped tissue between the two jaws at the desired clamping force.
9. The method of claim 8, wherein the desired range of clamped jaw separations is determined in response to a dimension of a staple or fastener to be used in stapling or fastening the clamped tissue.
10. The method of claim 8, wherein the desired range of clamped jaw separations comprises a distance between the jaws that is suitable for applying a staple to the tissue between the jaws.
11. The method of claim 6: wherein the grasping of the tissue between the two jaws at the grasping force is performed in response to a user command to grasp and before measuring the grasping separation parameter; the method further comprising: therapeutically clamping the grasped tissue between the jaws at the clamping force in response to a user command to clamp and after providing the indication of predicted success, or; releasing the grasped tissue from between the jaws after providing the indication of predicted failure.
12. The method of claim 11: wherein the grasping occurs in a soft grip tissue manipulation mode and the clamping occurs in a therapeutic clamping mode; the method further comprising: switching from the soft grip tissue manipulation mode to the therapeutic clamping mode.
13. The method of claim 12, wherein switching from the soft grip tissue manipulation mode to the therapeutic clamping mode occurs in response to a user input command to clamp the tissue.
14. The method of claim 11: wherein grasping the tissue comprises driving the jaws with a grasping torque applied by an actuator system; and wherein the grasping separation parameter is measured during application of the grasping torque.
15. The method of claim 1, wherein the separation parameter comprises an angle between the jaws or a distance between the jaws.
16. The method of claim 1, wherein the desired clamping force is at least twice the grasping force.
17. The method of claim 1, wherein the desired clamping force is between 5 to 10 times the grasping force.
18. The method of claim 1: wherein the indication comprises predicted clamping failure when the measured separation parameter is greater than a desired grasping separation; and wherein the indication is of predicted clamping success when the measured separation parameter is equal to or less than the desired grasping separation parameter.
19. The method of claim 18: wherein each of the jaws has a distal tip; and wherein the separation parameter comprises a separation distance between the distal tips of the jaws.
20. The method of claim 19, wherein the desired grasping separation is a distance within a range of about 0.7 mm to 8 mm.
21. The method of claim 19, wherein the desired grasping separation is a distance of about 4 mm.
22. The method of claim 19, wherein the grasping force corresponds to a tip force between the distal tips of the jaws within a range from about 3 lb-f to 10 lb-f.
23. The method of claim 19, wherein the clamping force corresponds to a tip force between the distal tips of the jaws within a range from about 30 lb-f to 70 lb-f.
24. The method of claim 18, further comprising determining the desired grasping separation parameter in response to one or more clamping parameters, the or each clamping parameter including any or all of a dimension of the jaws, a texture of a clamping surface on the jaws, a dimension of a staple, and a characteristic of the material being clamped.
25. The method of claim 24, wherein the characteristic of the material includes a type of tissue, a thickness of tissue, and a stiffness of tissue.
26. The method of claim 18, wherein the desired grasping separation parameter comprises an angle between the jaws.
27. The method of claim 26, wherein the angle between the jaws is within a range from 1 degree to about 10 degrees.
28. The method of claim 1, further comprising: repositioning the jaws relative to the material after the indication of predicted failure; after the repositioning of the jaws, grasping with the jaws at the grasping force while measuring a second grasping separation between the jaws; and outputting a second indication that indicates a second predicted success or failure of clamping the grasped material between the repositioned jaws at the desired clamping force in response to the measured second grasping separation between the repositioned jaws.
29. An apparatus comprising: a first and a second jaw; a drive system coupled to the jaws; a user interface; and an electronic data processor coupled to the drive system and the user interface; wherein the drive system is configured to close the jaws on a body tissue at a grasping force; wherein the electronic data processor is configured to measure a grasping separation parameter between the jaws; and wherein based on the measured grasping separation parameter, the electronic data processor outputs an indicator that is predictive of success or failure in clamping the tissue between the two jaws at a desired clamping force, the desired clamping force being within a predetermined range of forces greater than the grasping force.
30. The apparatus of claim 29, wherein the processor determines the grasping separation parameter between the jaws from positional data transmitted from the drive system.
31. The apparatus of claim 29, further comprising: a sensor for measuring the grasping separation parameter between the first and second jaw.
32. The apparatus of claim 29, wherein the grasping separation parameter comprises an angle between the jaws or a distance between the jaws.
33. The apparatus of claim 29: wherein the processor outputs the indicator to a user interface; and wherein the indicator comprises a graphical indicator predictive of success or failure in clamping the tissue grasped between the jaws at the desired clamping force to a desired clamped jaw separation, the desired clamped jaw separation being within a predetermined range of separations.
34. The apparatus of claim 33, wherein the desired clamped jaw separation comprises a suitable separation for applying a staple to the tissue between the jaws.
35. The apparatus of claim 29: wherein the data processor has a tissue soft grip mode in which the jaws can be positioned so as to receive the body tissue between the jaws and in which the jaws can be closed so as to grasp the body tissue at the grasping force; wherein the processor also has a therapeutic clamping mode in which the jaws close so as to clamp the body tissue at the clamping force; and wherein a user interface displays the indication of predicted clamping success or failure while the data processor is in the soft grip mode.
36. The apparatus of claim 29, wherein the indicator includes any or all of an audio sound, a visual indicator, and a sensory indicator.
37. The apparatus of claim 35, further comprising: a controller for switching between the soft grip and therapeutic clamping modes.
38. The apparatus of claim 35: wherein the drive system further comprises an actuator system that can apply a first and second torque; the actuator system being coupled to the jaws such that, in the soft grip mode, applying the first torque effects grasping with the jaws at the grasping force, and in the therapeutic clamping mode, applying the second torque effects clamping with the jaws at the clamping force.
39. The apparatus of claim 38, wherein the actuator system comprises one or more actuators, the or each actuator comprising any or all of an electric motor, a hydraulic actuator, a pneumatic actuator, and a variable torque output actuator.
40. The apparatus of claim 38, wherein the actuator system is coupled to the jaws through one or more mechanisms of the drive system.
41. The apparatus of claim 40, wherein the mechanism comprises any or all of a cable, a hypotube, and a leadscrew.
42. The apparatus of claim 35, wherein the indicator is indicative of a relationship between the separation parameter and a reference separation parameter, from which relationship the prediction of failure or success can be determined by a user.
43. The apparatus of claim 35, wherein the indicator is further indicative of a time elapsed after a determination of successful clamping of the tissue.
A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which includes minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient'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.
Minimally invasive telesurgical robotic systems have been recently been developed to increase a surgeon'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.
A huge variety of tools have been developed for open surgery, many (though not necessarily all) of which have been successfully modified for minimally invasive surgical procedures. For example, manual clamps, linear cutters, and stapling devices can apply significant therapeutic clamping forces on tissues, which can enhance a variety of surgical procedures. Unfortunately, work in connection with the present invention indicates that adapting open surgical clamping devices (and developing methods for safely and effectively using them) within minimally invasive settings may be more challenging than expected. In particular, developing and using surgical clamping jaws capable of generating desired clamping force while also providing the desired maneuverability for use within size-restricted minimally invasive surgical access and treatment sites has proven to be quite difficult. Transferring the advantages available from surgical staplers, linear cutters, and surgical clamping tools to robotic surgical settings may involve even more challenges, particularly given the different paradigms in surgeon-directed tool movement, tool activation, and physician feedback presented by the new telesurgical treatment systems.
Thus, there is believed to be a need for improved methods and systems for surgical staplers, linear cutters, and/or other clamping surgical tools. Such tools may be beneficial in a wide range of surgical applications, particularly in minimally invasive and/or robotic surgical applications.
Improved systems and methods to facilitate clamping are provided. The claimed methods and system can be used to help predict whether clamping a body tissue grasped between jaws at a desired clamping force is likely to be successful before attempting to clamp. The claimed systems and methods are particularly useful in surgical applications involving clamping of a body tissue between two jaws of an end effector. Many surgical applications involve clamping of a body tissue at a clamping force sufficient for cutting, sealing and/or stapling of the clamped tissue. Since high force clamping may potentially damage tissues if clamping fails, the present methods and systems are particularly advantageous as they indicate a prediction as to the likelihood of clamping success before clamping is attempted. 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 indicating whether clamping of a tissue grasped between a first and second jaw is likely to be successful. The method includes determining and/or measuring a separation between two jaws grasping a tissue at a grasping force and, in response to the determination of the separation, outputting on a user interface an indication of a prediction of whether clamping of the grasped tissue at a desired clamping force is likely to be successful. In such methods, the clamping force is greater than the grasping force and, in some embodiments, the clamping force may comprise a first predetermined range of forces, each larger than the grasping force. The indicator of whether clamping success is likely may also comprise an indicator whether clamping success at a desired clamping force and at a desired clamping separation is likely. The desired clamping separation may comprise a predetermined range of separations. Furthermore, the separation may be expressed in terms of a separation angle between the first and second jaw or a separation distance between jaw members. In many embodiments, the desired clamping separation is suitable for firing a staple of a given size through the tissue clamped between the jaws, cutting the grasped tissues, and/or sealing the grasped tissue. The first and second jaws will typically be part of an end effector. The first and second jaw may comprise 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 certain embodiments, the prediction may be based also on the stiffness of the tissue. The stiffness of the tissue may be input, if known, or may be estimated based on the grasping force and separation or on the rate of change of separation as the grasping force is applied. For example, the estimation of stiffness may be based on an empirically derived relationship between these factors and tissue stiffness.
The claimed methods provide an indication of clamping success and/or clamping failure in response to a separation parameter between a first and second jaw, the first and second jaw having a body tissue grasped therebetween. In some embodiments, the indication is provided in response to the separation parameter and the grasping force. One embodiment of the method includes grasping the tissue with the first and second jaw, typically in response to a command from a user. The method further includes clamping the tissue between the first and second jaw at the clamping force, after the system provides an indicator that clamping success is likely. The system clamps the tissue typically in response to a command from a user to clamp the tissue, after the system has provided an indication of whether clamping success or failure is likely. One embodiment of the claimed method includes releasing the grasped tissue after the system has provided an indication of a prediction of clamping failure. The system releases the grasped tissue typically in response to a command from a user to release the tissue from between the jaws.
In another aspect, the system and methods include a soft grip mode, in which the first and second jaw grasp a body tissue at a grasping force, and a clamping mode, wherein the first and second jaw clamp the grasped body tissue at a clamping force, the clamping force being greater than the grasping force. A mechanism coupled with the jaws causes the jaws to close so as to grasp and/or clamp the body tissue between the first and second jaw. The mechanism may be one mechanism coupled with an actuator, such as a motor, or, alternatively, the mechanism may comprise multiple mechanisms for exerting forces of differing magnitudes. The actuator may comprise an actuator system including one or more actuators. An actuator maybe any or all of an electric motor, a hydraulic actuator, a pneumatic actuator, and a variable torque output actuator. In embodiments having a soft grip mode and a clamping mode, the system typically switches between modes in response to a user command after the system has provided an indication that clamping of the grasped tissue would likely be successful.
In most embodiments, the separation parameter is measured and/or determined by the system during application of a grasping force or torque. The system may determine/measure the separation between jaw members from positional data obtained by the robotic system controlling the jaw members, 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. Typically, the clamping force is at least twice that of the grasping force, preferably about 5 to 10 times greater than the grasping force.
In another aspect of the invention, the indication of the clamping prediction is provided on a user interface. Preferably, the indication is a visual indicator superimposed over a display providing images of the surgical tools during a surgical procedure. In other embodiments, the indication of the clamping prediction may be any of an audio, visual or sensory indicator so as to communicate to the user a prediction of whether clamping is likely to be successful. In another aspect of the invention, the indication of clamping prediction may further include an indication of whether it is safe to initiate a stapling action. For example, after a prediction that clamping is likely and clamping has been completed, a timer may be initiated such that once a pre-determined amount of time has elapsed after successful clamping, an indicator is displayed over the display that it is safe to proceed stapling into the clamped tissue. A clamping timing indicator may be advantageous as it may reduce the amount of clamped tissue over time or reduce the amount of fluid within the tissue so as to reduce bleeding during stapling and help achieve hemostasis. The timing indicator may also track elapsed time of clamping after stapling of the clamped tissue so as to reduce bleeding or to aid in achieving hemostasis of the stapled tissue.
In another aspect, the prediction of clamping is provided in response to the separation parameter between grasped jaws as determined and/or measured by the system. In many embodiments, if the measured separation is greater than a threshold or a desired grasping separation parameter, then the prediction is indicative of likely clamping failure, while if the grasping separation is equal to or less than the desired grasping separation parameter, the prediction is indicative of likely clamping success. In some embodiments, the threshold or desired grasping separation parameter may be based in part on an apparent or estimated tissue stiffness. The desired separation may comprise either an angle between jaws or a distance between jaws, and the separation parameter may be a discrete parameter or a predetermined range of values. For many applications, the threshold or desired grasping separation is an angle of about 8 degrees or a distance of about 6 mm between tips of the jaw members. In one embodiment, a 4 degree angle results in a gap of approximately 3 mm between the tips of the jaws. In general, when the tissue is successfully clamped, the gap between jaws is between 1.3 mm to 2 mm, although one of skill in the art would appreciate that this value may vary depending on the application. In embodiments where the desired separation parameter is a predetermined range, clamping success may be indicated when the measured separation is within the predetermined range. For example, a predetermined range of desired grasping separation parameters may be from 1 to 10 degrees, preferably 1 to 8 degrees, or, in terms of distance, the range of desired grasping separation parameters from 0.7 mm to 8 mm, preferably 2 to 5 mm. Ideally, the desired target separation is approximately 4 mm. The desired separation values or ranges may vary according to any number of variables, including but not limited to: a dimension of the first or second jaw, a staple length, a staple size, a stapler angle of articulation, a thickness of the body tissue, a type of body tissue, a characteristic of the body tissue the desired clamping force or the desired clamping separation. In many embodiments, the grasping force between the tips of the jaws will be within a range from about 3 lb-f to 10 lb-f, preferably about 5 lb-f, and the clamping force between the tips of the jaws will be within a range from about 30 to 70 lb-f, preferably about 50 lb-f. The grasping force and desired clamping force may vary according to any of the above variables or by the type of surgical application (e.g. tissue cutting, sealing of tissue, and/or stapling of tissue).
In another aspect, the present invention includes a system for performing the claimed methods. Ideally, the system comprises a first and second jaw, a drive system coupled to the jaws, a user interface, and an electronic data processor coupled to the drive system. In many embodiments, the drive system closes the jaws on tissue at a predetermined grasping force, the electronic data processor measures a distance between the jaws, and based on the measured distance between the jaws, the electronic data processor outputs to the user interface a prediction of success of clamping the tissue between the two jaws at a desired clamping force, wherein the clamping force is within a first predetermined range that is larger than the grasping force, and wherein the clamped jaw separation distance is within a second predetermined range. Ideally, the second predetermined range comprises a distance between the jaws that is suitable for applying a staple to the tissue between the jaws.
The system may also comprise one or more modes of operation. In some embodiments, the system comprises a soft grip mode and a clamping mode. In the soft grip mode, the jaws close or close so as to grasp the body tissue at the predetermined grasping force. In the clamping mode, the jaws close so as to clamp the body tissue at the clamping force. Typically, the system only provides a prediction of clamping success when in the grasping mode, such that a surgeon may grasp tissue in the grasping mode in preparation for clamping the grasped tissue. In embodiments having multiple modes, the system may further include a controller for switching between modes.
The system may include an actuator system coupled with the jaws through a mechanism for effecting movement of the jaws so as to grasp and/or clamp the body tissue. In some embodiments, the mechanism may include cables and a linkage. In many embodiments, the mechanism comprises a lead screw and cam. In some embodiments, particularly in embodiments having multiple modes, a first mechanism effects grasping of the jaw and a second mechanism effects clamping with the jaws. For example, the first mechanism may comprise cables and the second mechanism may comprise a lead screw. Effecting grasping with cables would be ideal for providing a fast response with a relatively low force, while a lead screw would be more suited for provided a higher force despite having a longer response time. The first actuation mechanism can provide a low force for grasping the body tissue between jaw members, and the second actuation mechanism can provide a high clamping force mode. For example, in many embodiments, the maximum clamping force of the movable jaw provided by the second actuation mechanism is larger than a maximum grasping force provided by the first actuation mechanism.
The first and second actuation mechanisms can employ different force transmission mechanisms corresponding with the force requirements for the low force grasping mode and the high force clamping 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, and a force used by the second jaw actuation mechanism to move the jaw from the open to the closed position can include a torque. In many embodiments, the first jaw actuation mechanism for use in the low force grasping mode includes a cable-driven mechanism, with the second jaw actuation mechanism for use in the high force clamping mode includes a leadscrew-driven mechanism.
Any of the above described methods may be used in the clamping of any material and may be used in application that are non-surgical in nature. For example, the above described methods may be used to indicate to a user a clamping prediction regarding the clamping of a flexible compliant material in an industrial process.
FIG. 8A illustrates components of a cable-driven actuation mechanism, in accordance with many embodiments.
FIG. 8B is a perspective view of the end effector of FIG. 8A with a portion of the articulated jaw removed to show cable-driven actuation mechanism components disposed behind the articulated jaw used to articulate the jaw towards a closed configuration, in accordance with many embodiments.
FIGS. 8C through 8F illustrate opposite side components of the cable-driven actuation mechanism of FIG. 8A used to articulate the jaw towards an open configuration.
FIG. 9A is a perspective view illustrating a cable actuation mechanism, showing a cable used to articulate the jaw towards a closed configuration, in accordance with many embodiments.
FIGS. 13A through 13C depict an end effector having a first and second jaw and illustrate the grasping separation between jaws in a grasping and clamping configuration, in accordance with many embodiments.
FIGS. 14A-14B illustrate an end effector in a grasping configuration, in accordance with many embodiments.
FIGS. 15A-15B illustrate the user interface assembly having an indicator of a prediction of tissue clamping, in accordance with many embodiments.
FIGS. 16A-16B illustrate examples of indicators of tissue clamping predictions, in accordance with many embodiments.
FIGS. 17-19 illustrate methods, in accordance with many embodiments.
FIGS. 20-21 illustrate flow charts utilizing methods in accordance with many embodiments.
FIGS. 22A-22B illustrate additional examples of indicators in accordance with many embodiments.
Improved systems and methods related to clamping of body tissues are provided. The present invention relates to providing an indicator of whether clamping of grasped tissue is likely before attempting to clamp the tissue. The invention may be used in systems having jaw members for clamping a body tissue, particularly in surgical systems used in minimally invasive surgical applications. Typically, systems utilizing the claimed methods have jaws that grasp a body tissue at a low force and subsequently clamp the body tissue at a higher force. Grasping the body tissue at a low force allows a physician to manipulate and position the body tissue between the jaw members without causing damage to the tissue, while clamping at a higher clamping force allows the physician to perform various procedures, such as tissue cutting and sealing or stapling. 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.
In many embodiments, the two jaws comprise an articulated jaw that moves toward a stationary portion of the end effector. In such embodiments, the stationary portion of the end effector comprises the second jaw. 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 grasps a body tissue at the grasping force between the jaws of the surgical tool, then clamps the body tissue at the higher clamping force. Periodically, the jaws may fail to successfully clamp the tissue at the higher clamping force, which may potentially result in damage to the tissue due to the high clamping forces. For example, the jaws may clamp on the tissue but the jaw tips may be separated further than desired due to excess deflection, resulting in potential tissue damage. The jaws may fail to successfully clamp the tissue for a variety of reasons, including insufficient or excess tissue grasped between the jaws, including interference from an adjacent tissue, such as a bone, or slippage of the tissue from between the jaws. Therefore, it would be advantageous for a physician to be able to predict when clamping failure may occur before clamping, thereby avoiding any potential damage to the tissue. The described systems and methods provide an indication to the physician of a prediction of whether clamping of the body tissue will be successful. Clamping may be considered successful when the jaws are in the clamped position and the distance between the jaws is sufficient for performing a desired therapy, such as firing a staple through the clamped tissue.
The indication of whether clamping success is more likely than not may be based, in whole or in part, on the separation between the jaw members while grasping the tissue therebetween. Ideally, the methods include grasping a tissue at the grasping force, measuring and/or determining a separation between the jaw members, and providing an indication to the physician as to whether clamping of the grasped tissue is more likely than not. The methods may further include measuring or determining the relative stiffness of the grasped tissue. These systems and methods of the present invention are particularly beneficial when used in minimally invasive surgery applications. Additionally, the indication of clamping success or failure may further include predictions at multiple grip forces (e.g. sequentially higher forces), such that a user may grip with a force that is indicated as likely resulting in successful clamping. In some embodiments, this feature may be extended to consider the likelihood of clamping success or failure based on jaw positions during a continuously increasing grip force. The clamping force may also include a variable clamping force that is dependent on a relationship between jaw position and gripping force. For example, if the distance between jaws is greater than desired, such as may occur when an indication of likely clamping failure is indicated, a higher clamping force may be applied (e.g. by the user or automatically) and a second data point measured to determine an indication of a clamping prediction at the higher clamping force.
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'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 grasping and clamping the 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's Console 16. Electronics Cart 24 includes a Processor 27 for measuring a separation parameter between the jaw members of the tool. The grasping separation parameter may be measured directly or indirectly. The separation may be measured directly by the processor from the actual jaw members or from images representing the positions of the jaw members, or from various sensors of the system. For example, a Hall-effect type sensor can be positioned near the anvil jaw pivot to measure the closure angle of the jaws. The Hall-effect type sensor can be placed in the staple cartridge (or in either jaw of a pair of jaws) and a magnet correspondingly positioned in the anvil jaw (or opposing jaw). The sensor can then sense the magnet's proximity to determine if the anvil jaw is sufficiently closed. In another example, a shape sensing optical fiber can be placed in the jaw so that the jaw angle can be sensed. In some embodiments, at least one jaw may be equipped with a depth gauge and the opposite jaw may be equipped with a sensor to measure the depth gauge. For example, the depth gauge may be a small retractable needle that can be deployed once tissue is grasped to measure the separation distance between jaws. The separation may also be measured indirectly by calculating the separation from the tool positional data, such as from positional data, or derivatives thereof, obtained by the PSM. The processor may also provide the indication as to whether clamping is more likely than not in response to the separation parameter. The indication may be determined according to a formula or algorithm or obtained from a predetermined table of values. The system 10 then communicates an indicator of the prediction to the physician on the Surgeon's Console 16.
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 measure and/or determine a separation parameter between jaw members of the tool and to determine a prediction of clamping success in response to the measured separation parameter. Processor 27 may also process captured images for subsequent display, such as to a Surgeon on the Surgeon'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's Console 52. As discussed above, a Surgeon's Console 52 (such as Surgeon'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 clamping of a body tissue, the Surgeon can command the tool of the Patient Side Cart 54 to grasp a body tissue between jaw members of an end effector. In response to this command, Processor 58 can measure the separation parameter between the jaw members grasping the tissue and subsequently determine a clamping prediction based in whole or in part on the separation parameter. The determination of the clamping prediction may also include the grasping force, the desired clamping force and the desired distance between jaw members in the clamped configuration. The Processor 58 then commands Display 60 to display an indicator of the prediction to the Surgeon. In response, to the 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 prediction of clamping success.
FIGS. 5A and 5B 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 grasping and clamping a body 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.
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 fast response/low force grasping mode, and a second actuation mechanism can be used to provide a high clamping force mode, the clamping force being greater than the grasping force. In many embodiments, the first actuation mechanism used to provide the fast response/low force articulation mode is back-drivable. In many embodiments, the second actuation mechanism used to provide the high clamping force articulation mode is non-back-drivable. Using independent actuation mechanisms may be beneficial in some surgical applications, for example, electrocautery sealing, stapling, etc., that may require multiple low force jaw placement clampings before a high force jaw clamping is used to carry out the surgical tool's task.
In many embodiments, actuation of the jaws in the fast response/low force grasping mode is provided by a cable actuation mechanism that includes a pair of pull cables. In many embodiments, a pulling motion of a first cable of the pair articulates the articulated jaw towards a closed (grasped) configuration and a pulling motion of a second cable of the pair articulates the articulated jaw towards an open (ungrasped) configuration. In many embodiments, the cable actuation mechanism is back-drivable.
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.
FIG. 6A 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. 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 second drive shaft 80 rotates another leadscrew (not shown) of the detachable stationary jaw/staple cartridge reload 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 an actuator or motor system that is located in the proximal tool chassis.
FIGS. 7A through 10 illustrate the actuation mechanisms by which an end effector grasps a body tissue between its jaws in the low force grasping mode and clamps the body tissue grasped between its jaws with a higher clamping force.
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. 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 0.1 Newton meter and the leadscrew 82 has approximately 30 turns.
FIGS. 8A through 8F 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 closed 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 closed 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. 8A and 8B) 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 closed configuration.
The second linkage 118 (shown in FIGS. 8C through 8F) 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 closed 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.
In many embodiments, the fast response/low force mode is provided by a cable actuation mechanism that is back-drivable. For example, an external force applied to the articulated jaw can be used to rotate the articulated jaw towards the clamped configuration and back-drive the cable actuation mechanism. With a cable actuation mechanism that comprises a pair of pull cables wrapped around a capstan, an external force that rotates the articulated jaw towards the closed configuration produces an increase in tension in one of the pull cables and a decrease in tension in the other pull cable, thereby causing the capstan to rotate in response. As is known, such a cable driven system can be configured to have sufficient efficiency for back-drivability. Likewise, an external force applied to the articulated jaw can be used to rotate the articulated jaw towards the open configuration and back-drive the cable actuation mechanism. As discussed above, a back-drivable fast response/low force actuation mechanism provides a number of benefits.
FIG. 11 is a simplified perspective view 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. Although tool assembly 170 has been described as having a first and second actuation mechanism, in some embodiments tool assembly 170 could be constructed with a single actuation mechanism driven with a variable force motor such that the tool could both grasp body tissue with a relatively low force and subsequently clamp the grasped body tissue with a higher clamping force with the single actuation mechanism.
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 closed configuration. The second actuation mechanism 192 couples the drive motor 184 to the articulated jaw 194 so as to articulate the end effector into the clamped/closed configuration from the open configuration. The first actuation mechanism can be a cable actuation mechanism, for example, an above discussed cable actuation mechanism that provides the fast response/low force mode. In many embodiments, the first actuation mechanism is back-drivable. 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. In many embodiments, the second actuation mechanism is non-back-drivable. In both modes, the position of the jaw members is obtained by the PSM coupled with end effector 188. From the positional data obtained by the PSM during grasping of a body tissue with the end effector, Processor 191 can determine the separation parameter and associated prediction of clamping success with the end effector at the clamping force.
FIGS. 13A-13C illustrate an example of the separation parameter end effector 188 and depicts end effector 188 in both the grasping and clamping positions. FIG. 13A depicts the jaws of end effector 188 wherein the separation parameter (s) is a distance between the tips of the jaw members or may be an angle between jaw members. FIG. 13B illustrates end effector 188 grasping a body tissue (T) between jaw members at grasping force (Fg). In this embodiment, the system measures the separation parameter when the body tissue T is grasped between jaw members at known force Fg. In response, the system provides an indication on the user interface as to whether clamping of the grasped body tissue T at a higher clamping force (Fc) is more likely than not. The indication of the likelihood of clamping success may be based, in whole or in part, on the separation parameter, but may also be based on additional factors, including but not limited to: a type of body tissue (T) (e.g. bowel, stomach), a thickness of the body tissue, a desired clamping force Fc, and a desired separation between jaw members in the fully clamped state. For example, in one embodiment, the claimed system may provide an indication as to the likelihood of clamping the grasped tissue at the clamping force Fc in response to the grasping separation parameter being less than a threshold or desired grasping separation. Alternatively, if the measured separation is greater than the predetermined separation parameter, then the system may provide an indication to the user that clamping may likely not be successful. The predetermined separation parameter may vary according to any of the above stated additional factors. FIG. 13C illustrates end effector 188 having successfully clamped body tissue T between jaw members at clamping force Fc, the clamping force being within a desired range of forces greater than grasping force Fg.
FIGS. 14A-14B illustrate two examples of end effector 188 having grasped body tissue T at grasping force Fg. FIG. 14A depicts an example wherein the actual separation (sa) between the jaws of end effector 188 when grasping the tissue is less than the predetermined grasping separation or target separation (st) as determined for a clamping prediction at a given desired clamping force Fc and/or desired clamping separation. In this example, the system would predict successful clamping and provide an indication of the prediction to the Surgeon on the user interface. FIG. 14B depicts an example wherein the body tissue is positioned such that clamping may not be successful due to tissue slippage or insufficient tissue between the jaws of the end effector. In this example, the actual measured separation (sa) between the jaws of end effector 188 is greater than the predetermined separation or target separation (st) as determined for a clamping prediction at a given clamping force Fc and/or clamping separation. In this embodiment, the system would predict that clamping would likely not be successful and provide an indication of the prediction to the Surgeon on the user interface. After providing an indication that clamping would likely not be successful, the system may prevent the Surgeon from clamping, absent additional input from the user.
FIGS. 15A-15B illustrate the indication on the user interface Display 60 of System 10 as to whether clamping of grasped tissue would likely be successful. 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 predictions. The indication of clamping prediction may be superimposed over the images on the user interface display during the surgical procedure so as to seamlessly incorporate the feature into the surgical procedure. Preferably, the clamping prediction indicators only appear when the Surgeon effects grasping of the tissue in preparation for clamping. The indication of clamping prediction facilitates successful clamping of body tissue by the Surgeon during surgery, while minimizing the potential for tissue damage from unsuccessful clamping. FIG. 15A depicts Display 60 with the clamping prediction indicator 250 superimposed on the lower right area of the screen, wherein the indicator predicts clamping is more likely than not. FIG. 15B depicts Display 60 with the clamping prediction indicator 250 superimposed on the lower right area of the screen, wherein the indicator indicates a prediction that clamping will likely not be successful. Often, the Surgeon will not be able to visualize the entire surgical tool with an endoscope due to interference from the body tissue, or the Surgeon may be viewing visual representations of the tools. In FIGS. 15A-15B, the graphical representations of the jaws of end effector 189 on Display 160 are exaggerated and, generally, the Surgeon may not be able to ascertain whether clamping will be successful solely from viewing the images of the surgical tools on Display 60.
FIG. 16A-16B illustrate additional examples of the clamping prediction indicator 250. FIG. 16A depicts an example of an indicator wherein the clamping prediction is a gradient of likely clamping success. The system and methods may determine a prediction within the gradient based on various factors, including but not limited to: the difference between the actual separation and the predetermined target separation between jaws grasping the tissue, a type of tissue, a thickness of the tissue, or the desired clamping force and/or clamping separation. For example, the predetermined separation when the jaws are grasped tissue may be a range of acceptable grasping separations, and the further outside the range of predetermined grasping separation the actual measured grasping separation is, the less likely clamping success will be. For example, in one embodiment, if actual measured separation is within 0-2 degrees, then the system will display an indicator of 99% likelihood of clamping success. As the measured separation increases from 2-8 degrees, the likelihood decreases in a monotonically decreasing relationship, such as from 99% down to 10%. FIG. 16B depicts an embodiment having an indicator which toggles between two settings, a predicted clamping success setting and a predicted clamping failure setting. In this example, the indicator is simply a light that when lit indicates that clamping is more likely than not, and when dark indicates that clamping success is not likely.
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 measuring a separation between two jaws grasping a tissue at a known grasping force and a step 304 of indicating on a user interface that clamping success or failure is likely when clamping the grasped tissue between the two jaws at a higher clamping force. FIG. 18 is a simplified representation of a method 310 which further includes the step 312 of grasping a body tissue between jaws at a grasping force by the system typically in response to a command from a user and a step 318 of clamping the body tissue between the jaws at the clamping force in response to a command from a user to clamp the tissue after the system has measured the separation between jaws and provided an indication of predicted clamping success in steps 314 and 316, respectively. FIG. 19 is a simplified representation of a method 320 which further includes the step 334 repositioning the jaws on the body tissue in response to a command from a user to reposition the jaws after the system has performed step 332 of providing an indication that clamping success is likely.
FIGS. 20-21 depict flowcharts illustrating embodiments of the claimed methods. FIG. 20 is a flow chart showing an embodiment of the claimed method wherein the system reads the separation (jaw angle) from the PSM after the body tissue has been grasped between the jaws (MTM grips closed on tissue). If the separation (angle) is less than the predetermined separation (threshold angle), then the system indicates to the user that clamping is likely to succeed. If the separation (angle) is not less than the predetermined separation (threshold), then the system indicates to the user that clamping is unlikely to succeed. If the user provides an input to the system to clamp (blue pedal pressed), then the system proceeds with clamping of the tissue grasped within the jaws. FIG. 20 is a flow chart showing an embodiment of the claimed method incorporated into a surgical system for clamping and sealing a body tissue by firing a staple into the clamped tissue. In FIGS. 20-21, the systems may require user input, such as pressing a blue or yellow pedal, before performing a selected action.
FIGS. 22A-22B illustrate an indication on the user interface Display 60 of System 10 as to whether it is advisable to proceed with stapling of the clamped tissue. The indication may be solely an indicator of whether it is safe to proceed with stapling or may further include a timer for showing an elapsed time (or alternately a countdown) after clamping of the tissue with end effector 189. The indicator 250 may be similar to the indicator illustrated in FIGS. 15A-15B, however, may further include the above described features. The stapling safety indicator and/or timer features are advantageous as allowing the clamped tissue to remain clamped for a specified amount of time before stapling may slightly reduce the thickness of tissue being clamped by squeezing out fluid (e.g., blood) within the tissue to be stapled. Reducing the amount of fluid in the clamped tissue is advantageous as it may reduce the likelihood of bleeding from the staple insertion points during and after stapling. Typically, when tissue is properly clamped between the jaws of the end effector 189, a finite amount of time is required for the clamped tissue to compress (e.g., fluids squish out from the tissue between the jaws) before stapling is initiated. The amount of time needed for sufficient compression and reduction of fluid may vary according to the type and size of staple, the type of stapler and/or clamp, as well as the type and thickness of the tissue being clamped. For example, in performing staple of a bowel tissue, it has been shown that waiting for at least one minute after clamping before stapling of the tissue significantly reduces the amount of bleeding resulting from stapling; however one of skill in the art would appreciate that the duration of time to wait could be less than one minute or greater than one minute, often depending on the procedure and tissue to be stapled. Additionally, maintaining clamping of the tissue after stapling may further reduce bleeding from the stapled tissue and promote hemostasis. The indicator may provide an elapsed time (or a countdown from a recommended wait time) so that the system and/or the Surgeon can recognize that the required time has elapsed and that it is safe to proceed with stapling. In other embodiments, an additional indicator message (e.g., “wait to staple,” “proceed with stapling”) may aid in indicating to a surgeon that it is advisable to proceed with stapling of the clamped tissue. Such an indication may include, but is not limited to, a change in color in the time indicator display, a change in background color on the display, a light, a sound, or any other indicator suitable for communicating stapling safety and/or clamping duration to the Surgeon. The recommended clamping wait times may be pre-set in the system according to any of the variables of the procedure, or alternatively, may be input by the Surgeon.
In FIG. 22A of the above described embodiment, the Surgeon has successfully clamped the tissue with the jaws of end effector 189, a representation of which is visible on the Display 60. Indicator 250 in the lower right corner of the Display 60 indicates that clamping has been completed and further instructs the surgeon with the message “Wait to Staple,” while a timer indicates the time that has elapsed since successful clamping of the tissue. In this embodiment, the recommended time to wait before stapling is one minute. As shown in FIG. 22B, after one minute has elapsed, the indicator 250 displays the elapsed time with the message “Proceed to Staple,” after which the surgeon may proceed with stapling of the clamped tissue. In an alternate embodiment, the timer may restart after stapling of the tissue so as to allow a Surgeon to maintain clamping on the stapled tissue.

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