Circular stapler

Systems and methods for stapling tissue, a vessel, duct, etc., during a surgical procedure are provided. The surgical stapling systems generally include a circular stapling tool with a shaft extending therefrom that has an end effector at a distal end thereof. The end effector can have a staple deck and an anvil. The circular stapling tool can be configured to drive at least two circular rows of staples through tissue engaged between the staple deck and the anvil to thereby staple the tissue, and the tool can be configured to drive a knife through tissue engaged between the staple deck and the anvil to thereby cut the tissue. The surgical stapling system can also include a control system that is configured to communicate with the circular stapling tool.

FIELD

Electrically-powered surgical staplers and methods for using the same are provided.

BACKGROUND

More and more surgical procedures are being performed using electrically-powered surgical devices that are either hand-held or that are coupled to a surgical robotic system. Such devices generally include one or more motors for driving various functions on the device, such as shaft rotation, articulation of an end effector, scissor or jaw opening and closing, firing or clips, staples, cutting elements, and/or energy, etc.

A common concern with electrically-powered surgical devices is the lack of control and tactile feedback that is inherent to a manually-operated device. Surgeons and other users accustomed to manually-operated devices often find that electrically-powered devices reduce their situational awareness because of the lack of feedback from the device. For example, electrically-powered devices do not provide users with any feedback regarding the progress of a cutting and/or sealing operation (e.g., an actuation button or switch is typically binary and provides no feedback on how much tissue has been cut, etc.) or the forces being encountered (e.g., toughness of the tissue). This lack of feedback can produce undesirable conditions. For example, if a motor's power is not adequate to perform the function being actuated, the motor can stall out. Without any feedback to a user, the user may maintain power during a stall, potentially resulting in damage to the device and/or the patient. Furthermore, even if the stall is discovered, users often cannot correct the stall by reversing the motor because a greater amount of force is available to actuate than may be available to reverse it (e.g., due to inertia when advancing). As a result, time-intensive extra operations can be required to disengage the device from the tissue.

In addition, electrically-powered devices can be less precise in operation than manually-operated devices. For example, users of manually-operated devices are able to instantly stop the progress of a mechanism by simply releasing the actuation mechanism. With an electrically-powered device, however, releasing an actuation button or switch may not result in instantaneous halting of a mechanism, as the electric motor may continue to drive the mechanism until the kinetic energy of its moving components is dissipated. As a result, a mechanism may continue to advance for some amount of time even after a user releases an actuation button.

Accordingly, there remains a need for improved devices and methods that address current issues with electrically-powered surgical devices.

SUMMARY

Surgical stapling systems and methods for using the same are provided herein.

In one exemplary embodiment, a surgical stapling system is provided that includes a circular stapling tool with a housing and an instrument shaft extending therefrom with an end effector at a distal end thereof. The end effector can include a staple deck and an anvil movable relative to the staple deck. The circular stapling tool can be configured to drive inner and outer circular rows of staples through tissue engaged between the staple deck and the anvil to thereby staple the tissue. The circular stapling tool can also be configured to drive a knife through tissue engaged between the staple deck and the anvil to thereby cut the tissue. The system can also include a control system that is configured to communicate with the circular stapling tool and that is configured to selectively actuate the circular stapling tool to independently drive any one of the inner circular row of staples, the outer circular row of staples, and the knife.

The system can have numerous variations. For example, the control system can be configured to initiate actuation of the knife prior to commencement of actuation of at least one of the inner circular row of staples and the outer circular row of staples. In some examples, the circular stapling tool can include an inner staple drive assembly operable to drive the inner circular row of staples through the staple deck toward the anvil, an outer staple drive assembly operable to drive the outer circular row of staples through the staple deck toward the anvil, and a knife drive assembly configured to drive the knife through the staple deck toward the anvil.

The housing can be configured as a hand-held device, or in other embodiments the housing can include a tool mounting portion configured to mount to a motor housing on a surgical robot.

In one embodiment, the control system can be configured to control a displacement of the anvil from the staple deck and drive the knife when a threshold displacement is reached. In another example, the control system can be configured to monitor a displacement of the knife from the housing and retract the knife when the knife reaches a threshold displacement away from the housing. The control system can also be configured to drive any one of the inner circular row of staples, the outer circular row of staples, and the knife based on a predetermined time offset after driving one of the others of the inner circular row of staples, the outer circular row of staples, and the knife.

In another embodiment, the control system can be configured to control a travel distance of the inner staple drive assembly and the outer staple drive assembly. The control system can also be configured to control a rate of advancement of at least one of the inner staple drive assembly, the outer staple drive assembly, and the knife drive assembly based on a measured thickness of a tissue engaged between the anvil and the staple deck.

In another exemplary embodiment, a surgical stapling system is provided that includes an electromechanical tool with an instrument shaft and an end effector at a distal end thereof. The end effector can include a staple deck having inner and outer rows of staples disposed therein and an anvil movable relative to the staple deck. An inner staple driver can be operable to drive the inner row of staples through the staple deck toward the anvil. The end effector can also have an outer staple driver operable to drive the outer row of staples through the staple deck toward the anvil and a knife that is movable through an opening in the staple deck for cutting tissue engaged between the staple deck and the anvil. The system can also include a housing coupled to the shaft that has drive assemblies. The drive assemblies include an inner staple drive assembly operable to drive the inner stapler driver, an outer staple drive assembly operable to drive the outer staple driver, and a knife drive assembly operable to drive the knife. The system can further include a control system that is configured to communicate with the electromechanical tool and that is configured to selectively initiate actuation of each of the drive assemblies. This actuation can cause any one of the inner staple drive assembly, the outer staple drive assembly, and the knife drive assembly to be actuated prior to commencement of actuation of any other one of the inner staple drive assembly, the outer staple drive assembly, and the knife drive assembly.

The system can have various embodiments. For example, the control system can be configured to control a travel distance of the inner staple drive assembly and the outer staple drive assembly to thereby control a shape of staples being formed by the anvil. The control system can also be configured to control a rate of advancement of at least one of the inner staple drive assembly, the outer staple drive assembly, and the knife drive assembly based on a measured thickness of a tissue engaged between the anvil and the staple deck.

The housing can be configured as a hand-held device, such as with a battery disposed within the housing. In other embodiments, the housing can include a tool mounting portion configured to mount to a motor housing on a surgical robot.

In another aspect, a method for stapling tissue is provided that includes manipulating a surgical stapling device to engage tissue between an anvil and a staple deck on an end effector of the surgical stapling device. The method can also include inputting a command into a control system to instruct the control system to initiate actuation of the surgical stapling device. The control system can communicate with the surgical stapling device to independently actuate each of an inner staple drive assembly to drive an inner circular row of staples from the staple deck toward the anvil to staple the tissue engaged therebetween, an outer staple drive assembly to drive an outer circular row of staples from the staple deck toward the anvil to staple the tissue engaged therebetween, and a knife drive assembly to drive a knife from the staple deck toward the anvil to cut the tissue engaged therebetween.

The method can have numerous variations. In one example, the control system can wirelessly communicate with the surgical stapling device to actuate the surgical stapling device. In another example, the control system can control a travel distance of the inner staple drive assembly and the outer staple drive assembly to thereby control a shape of staples being formed by the anvil. The travel distance can be controlled based on a measured thickness of the tissue engaged between the staple deck and the anvil. In one example, the control system can control a rate of advancement of at least one of the inner staple drive assembly, the outer staple drive assembly, and the knife drive assembly based on a measured thickness of the tissue engaged between the staple deck and the anvil. In another example, manipulating a surgical stapling device can include manipulating a user input device wirelessly coupled to a surgical robotic system having the surgical stapling device coupled thereto. Manipulating a surgical stapling device can also include manipulating a handle housing of the surgical stapling device.

In another aspect, a surgical stapling system is provided that includes a circular stapling tool with a housing and an instrument shaft extending therefrom with an end effector at a distal end thereof. The end effector can include a staple deck and an anvil movable relative to the staple deck. The circular stapling tool can have a staple drive assembly that is configured to drive inner and outer circular rows of staples through tissue engaged between the staple deck and the anvil to thereby staple the tissue and can also have a knife drive assembly that is configured to drive a knife through tissue engaged between the staple deck and the anvil to thereby cut the tissue. The system can also include a control system that is configured to control advancement of the knife drive assembly toward the anvil and is configured to stop advancement of the knife drive assembly when the control system detects that the knife has fully passed through tissue engaged between the staple deck and the anvil.

The system can have a variety of embodiments. For example, the control system can detect that the knife has fully passed through tissue by monitoring a force required to advance the knife drive assembly. In another example, when the force required to advance the knife drive assembly changes at a rate that exceeds a predetermined threshold rate of change, the control system can stop advancement of the knife drive assembly. In another example, when the force required to advance the knife drive assembly changes by an amount that exceeds a predetermined delta, the control system can stop advancement of the knife drive assembly. The knife drive assembly can be coupled to a motor that advances the knife drive assembly, and the force to advance the knife drive assembly can be measured based on a current required to drive the motor.

In some embodiments, the control system can detect that the knife has fully passed through tissue by monitoring a velocity of the knife drive assembly. In another example, when the velocity of the knife drive assembly changes by an amount that exceeds a predetermined delta, the control system can stop advancement of the knife drive assembly. In one example, the control system can stop advancement of the knife drive assembly when the knife contacts a knife support surface on the anvil.

The housing of the device can be configured as a hand-held tool, or in other embodiments the housing can include a tool mounting portion that is configured to mount to a motor housing on a surgical robot when the control system is coupled to the surgical robot. The housing can include at least one motor disposed therein for driving the staple drive assembly and the knife drive assembly and at least one actuator thereon for actuating the at least one motor.

In another embodiment, a surgical stapling system is provided with an electromechanical tool that includes an instrument shaft and an end effector at a distal end thereof. The end effector can include a staple deck with inner and outer rows of staples disposed therein and an anvil movable relative to the staple deck. The end effector can also include an inner staple driver operable to drive the inner row of staples through the staple deck toward the anvil, an outer staple driver operable to drive the outer row of staples through the staple deck toward the anvil, and a knife that is movable through an opening in the staple deck for cutting tissue engaged between the staple deck and the anvil. The system can include a housing coupled to the shaft. The housing can have drive assemblies that include at least one staple drive assembly operable to drive the inner and outer staple drivers and a knife drive assembly operable to drive the knife. The system can also include a control system that is configured to communicate with the electromechanical tool and configured to actuate and control the drive assemblies. The control system can be configured to control the knife drive assembly based on at least one of a force required to advance the knife drive assembly and a velocity of the knife drive assembly.

The system can vary in numerous ways. For example, the at least one staple drive assembly can include an inner staple drive assembly operable to drive the inner staple drivers and an outer drive assembly operable to drive the outer staple drivers. In another example, the control system can be configured to detect passage of the knife through tissue engaged between the staple deck and the anvil based on at least one of the force and the velocity. The control system can be configured to stop advancement of the knife drive assembly when the control system detects passage of the knife through tissue engaged between the staple deck and the anvil based on at least one of the force and the velocity. In one example, when the force required to advance the knife drive assembly changes at a rate that exceeds a predetermined threshold rate of change, the control system can stop advancement of the knife drive assembly. In another example, when the force required to advance the knife drive assembly changes by an amount that exceeds a predetermined delta, the control system can stop advancement of the knife drive assembly.

In another example, the knife drive assembly can be coupled to a motor that advances the knife drive assembly, and the force to advance the knife drive assembly can be measured based on a current required to drive the motor. In one embodiment, when the velocity of the knife drive assembly changes by an amount that exceeds a predetermined delta, the control system can stop advancement of the knife drive assembly. In another example, the control system can be configured to stop advancement of the knife drive assembly when the knife contacts a knife support surface on the anvil. The housing can also include a tool mounting portion that is configured to mount to a motor housing on a surgical robot, and the control system can be coupled to the surgical robot. The housing can include at least one motor disposed therein for driving the staple drive assembly and the knife drive assembly, and at least one actuator thereon for actuating the at least one motor.

In another aspect, a method for stapling tissue is provided that includes manipulating a surgical stapling device to engage tissue between an anvil and a staple deck on an end effector of the surgical stapling device. The method can also include inputting a command into a control system such that the control system initiates actuation of the surgical stapling device. The control system can communicate with the surgical stapling device to advance the knife drive assembly to drive a knife from the staple deck toward the anvil to cut the tissue engaged therebetween, and to stop advancement of the knife drive assembly when the control system detects that the knife has fully passed through the tissue.

The method can have numerous variations. For example, the control system can detect that the knife has fully passed through the tissue by monitoring a force required to advance the knife drive assembly. The control system can also detect that the knife has fully passed through the tissue by monitoring a velocity of the knife drive assembly. In another example, the control system can wirelessly communicate with the surgical stapling device to actuate the surgical stapling device. Manipulating a surgical stapling device can include manipulating a user input device wirelessly coupled to a surgical robotic system having the surgical stapling device coupled thereto. In another example, manipulating a surgical stapling device can include manipulating a handle housing of the surgical stapling device.

DETAILED DESCRIPTION

It will be appreciated that the terms “proximal” and “distal” are used herein with reference to a user, such as a clinician, gripping a handle of an instrument. Other spatial terms such as “front” and “rear” similarly correspond respectively to distal and proximal. It will be further appreciated that for convenience and clarity, spatial terms such as “vertical” and “horizontal” are used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these spatial terms are not intended to be limiting and absolute.

Circular staplers can be used in a variety of surgical procedures (e.g., colorectal, bariatric, thoracic, etc.) to clamp down on layers of tissue, drive staples through clamped layers of tissue, and cut through clamped layers of tissue to substantially seal layers of tissue together near the severed ends of the tissue layers, thereby joining severed ends and creating an anatomical lumen. In some instances, when using a circular stapler to form an end-to-end anastomosis, staple formation and anastomosis integrity may be inadvertently and negatively affected by, for example, initially driving an annular row of staples through tissue while simultaneously severing excess tissue. For instance, when an initial row of staples is formed simultaneously during excess tissue severing, stapled tissue may begin to move due to forces absorbed from severing of excess tissue before staples are fully formed. Movement of stapled tissue before full formation of an initial row of staples may adversely impact the quality of an end-to-end anastomosis. Therefore, it may be desirable to fire a first row of staples into tissue before severing excess tissue. Firing a first row of staples into tissue before severing tissue may prevent unwanted movement of stapled tissue before completion of staple formation, which may increase the integrity of staple formation in an end-to end anastomosis. Additionally, staple formation may be negatively affected by simultaneously driving multiple annular staple rows to form an end-to-end anastomosis. Therefore, it may also be desirable to fire a first annular row of staples into tissue, and then fire an additional annular row(s) of staples into tissue sequentially before severing excess tissue. Alternatively, it may be desirable to fire a first annular row of staples into tissue before severing excess tissue, and then fire a second annular row of staples into tissue while simultaneously severing excess tissue. Firing a first row of staples into tissue may allow for the general shape of an end-to-end anastomosis for form, while sequentially firing a second row of staples into tissue may allow for a finer cinching of the end-to-end anastomosis to develop. It is therefore desirable to have a circular stapler with capabilities of independently firing annular rows of staples, and/or independently firing a knife assembly to sever excess tissue.

Accordingly, systems and methods for stapling tissue, a vessel, duct, etc., during a surgical procedure are provided. The systems and methods can be used in connection with a circular stapling tool having a housing with a shaft extending therefrom that has an end effector at a distal end thereof. The end effector can have a staple deck and an anvil. The circular stapling tool can be configured to drive at least two circular rows of staples through tissue engaged between the staple deck and the anvil to thereby staple the tissue, and the tool can be configured to drive a knife through tissue engaged between the staple deck and the anvil to thereby cut the tissue. A control system is provided that can be configured to communicate with a circular stapling tool and that is configured to selectively actuate the circular stapling tool to independently drive any one of the individual circular rows of staples and the knife. The system can thus selectively actuate any one row of staples and/or the knife to allow the system to have a greater degree of control over when stapling and cutting occurs in tissue, giving a great deal more control and reliability to the system than in stapler versions that require simultaneous and/or overlapping stapling and cutting. In other embodiments, a control system can be configured to control advancement of the knife drive assembly toward the anvil and to stop advancement of the knife drive assembly when the control system detects that the knife has fully passed through the tissue. Because the system can stop advancement when the knife has fully passed through tissue, the system can provide more control to an operation while using less force on the knife and still ensuring tissue will be fully cut.

An exemplary surgical stapling system can include a variety of features to facilitate application of a surgical staple as described herein and illustrated in the drawings. However, a person skilled in the art will appreciate that the surgical stapling systems can include only some of these features and/or it can include a variety of other features known in the art. The surgical stapling systems described herein are merely intended to represent certain exemplary embodiments. Moreover, while the drive and control systems are shown and described in connection with circular staplers, a person skilled in the art will appreciate that these systems can be used in connection with other surgical staples or surgical devices, such as forceps/graspers, needle drivers, scissors, electrocautery tools, clip appliers/removers, suction tools, irrigation tools, etc. Further, a person skilled in the art will appreciate that the surgical stapling systems described herein have application in conventional minimally-invasive and open surgical instrumentation as well as application in robotic-assisted surgery.

Surgical Stapling Device

As indicated above, in an exemplary embodiment control systems are provided for controlling actuation of a surgical stapling device.FIG. 1illustrates one embodiment of a circular surgical stapler10for use with a control system. As shown inFIG. 1, the stapler10includes a handle assembly11and a removable shaft assembly16. The illustrated handle assembly11includes a housing12with a stationary handle14, a closure trigger32, and a firing trigger33. The housing12can be configured for operative attachment to a shaft assembly16, which has a surgical end effector18at a distal end thereof. As illustrated, the shaft assembly16is releasable and removable from the housing12, however the shaft assembly16can be integrally formed or fixedly attached to the housing. As described below, the end effector18is configured to perform one or more surgical tasks or procedures. In particular, end effector18shown inFIG. 1is operable to perform a circular cutting and stapling procedure. The handle14operatively supports a drive system therein that is configured to generate and apply various control motions to corresponding drive assemblies extending through the shaft assembly16. The drive system in the handle assembly11can include one or more gear assemblies that can be driven by one or more motors (not shown), either located in the handle assembly11or external to the handle assembly11, e.g., within a surgical robotic system. In the illustrated hand-held embodiment, the motor(s) are located within the handle and powered by a battery. In certain exemplary embodiments, the drive assemblies can include a closure drive assembly that can function to close the anvil and grasp tissue by the end effector18, one or more firing assemblies that can fire one or more staple rows disposed in the end effector18into tissue grasped by the end effector18, and a cutting assembly that can fire a knife disposed in the end effector18to sever tissue grasped by the end effector18.

Additional details regarding the drive system and various drive assemblies and the structure of the circular stapler are disclosed in U.S. patent application Ser. No. 15/634,620, filed Jun. 27, 2017, titled “Surgical Stapler with Independently Actuated Drivers to Provide Varying Staple Heights,” which is incorporated herein by reference in its entirety. Additional details regarding the various circuitry and control systems used to actuate the circular stapler may be found in U.S. Pub. No. 2014/0263541, the disclosure of which is incorporated by reference herein and/or U.S. Pub. No. 2015/0272575, the disclosure of which is incorporated by reference herein. Additional details on surgical staplers, such as conventional surgical staplers, are disclosed in U.S. Pat. Nos. 8,469,252, 8,602,286 and 9,713,468, each of which is incorporated herein by reference in its entirety.

As previously noted, more and more surgical procedures are being performed using electrically-powered surgical devices that are either hand-held or that are coupled to a surgical robotic system. Unlike manually-operated devices, electrically-powered surgical devices can lack control and tactile feedback, thereby reducing a surgeon's ability to effectively, accurately, and safely use these devices. Further, manually-operated devices are typically displacement controlled in which mechanical hard stops are used to allow the device to shift to different stages of operation, for example, from firing to cutting. However, using mechanical stops has its disadvantages. For example, a user can be limited in assessing whether a jam has occurred in the device, if the staples are fully formed, or whether the knife has cut through the tissue.

Accordingly various embodiments of drive and control systems are provided for producing real-time feedback during the operation of electrically-powered surgical devices so as to enable a surgeon or other user to effectively and accurately use such devices. In general, a drive system can be operably coupled to the staple shaft assembly and to at least one motor that is configured to drive various drive assemblies for actuating the device, and the control system can be operably coupled to the at least one motor and it can be configured to actuate the at least motor to drive the drive system and thereby control actuation of the drive assemblies. The control system and the motors can be disposed within the handle housing for use as a hand-held device, similar to the device ofFIG. 1, or they can be located external to the handle housing, such as in a surgical robotic system. For example,FIG. 2illustrates an exemplary embodiment of a surgical robotic system having a robotic arm255wirelessly coupled to a control system258with a console with a display and two user input devices. One or more motors (not shown) are disposed within a motor housing256that is coupled to an end of the robotic arm255. A tool or drive system housing260on a surgical tool can house a drive system (not shown) and it can be mounted to the motor housing256to thereby operably couple the motor(s) to the drive system. As a result, when the motors are activated by the control system, the motor(s) can actuate the drive system, which in turn can drive the various drive assemblies. As shown inFIG. 3, a staple shaft assembly218extends from the tool housing260. During surgery, the staple shaft assembly218can be placed within and extend through a trocar259that is mounted on the bottom of a carrier261extending between the motor housing256and a trocar support. The carrier261allows the tool to be translated into and out of the trocar259.

Drive System

FIG. 3illustrates an exemplary embodiment of surgical stapling system200having a tool housing260containing a drive system257and being coupled to a proximal end220pof an instrument shaft220of a staple shaft assembly218. The drive system257is shown coupled to four motors276,286,295,298that are operably coupled to a control system258. As noted above, the motors and the control system can be located within the tool housing260to form a powered hand-held device, such as shown inFIG. 1, or they can be located external of the housing260, such as in a robotic system as described with respect toFIG. 2. Moreover, aside from the differences described in detail below, the staple shaft assembly218can be similar to staple shaft assembly18ofFIG. 1. Further, for purposes of simplicity, certain components of the staple shaft assembly218are not illustrated inFIG. 3.

While the drive system257can have a variety of configurations, in this exemplar embodiment, the drive system257includes gearing assemblies that are part of four drive assemblies: an anvil clamping drive assembly262configured to cause an anvil600to advance and retract in distal and proximal directions relative to the housing260; an outer staple drive assembly268configured to cause an outer staple driver750to advance in distal and proximal directions relative to the housing260to deploy staples; an inner staple drive assembly264configured to cause an inner stapler driver770to advance in distal and proximal directions relative to the housing260to deploy staples; and a knife drive assembly266configured to cause a knife assembly710to advance in distal and proximal directions relative to the housing260to sever tissue. Additionally and/or alternatively, a shaft rotation mechanism can be incorporated into one or more of the drive assemblies to cause rotation of the instrument shaft220. Each drive assembly, as well as the gearing in the drive system for driving the drive assemblies, is discussed in more detail below. Each gearing assembly in the drive system can be coupled to a rotary motor shaft of a corresponding motor. During actuation, the corresponding motor can actuate the gearing to thereby actuate the drive assemblies. Further, as described below, one or more motors can be coupled to a corresponding rotary encoder that provides displacement information to the control system258for at least one of the anvil clamping drive assembly262, the outer staple drive assembly268, the inner staple drive assembly264, and the knife drive assembly266during operation of the drive system257. Alternatively or in addition, the one or more motors can be coupled to a corresponding torque sensor that provides the control system258with information about the amount of force being applied to the motor(s) during operation of the drive system257.

Motors

As noted above, one or more motors can be coupled to one or more drive assemblies of the drive system to move the anvil, drive the inner and/or outer rows of staples, and drive the knife or cutting element. The motor(s) can be located within the surgical device itself or, in the alternative, coupled to the surgical device such as via a robotic surgical system. Each motor can include a rotary motor shaft that is configured to couple to the drive system of the surgical device so that the motor can actuate the drive system to cause a variety of movements and actions of the device.

It should be noted that any number of motors can be used for driving any one or more gear assemblies of the drive system on a surgical device. For example, one motor can be used to actuate two different gear assemblies for actuating different drive assemblies. Moreover, in certain embodiments, the drive system can include a shift assembly for shifting the drive system between different modes for causing different actions. A single motor can in other aspects be coupled to a single drive assembly. A surgical device can include any number of drive assemblies and any number of motors for actuating the various drive assemblies. The motor(s) can be powered using various techniques, such as by a battery on the device or by a power source connected directly to the device or connected through a robotic surgical system.

Additional components, such as sensors or meter devices, can be directly or indirectly coupled to the motor(s) in order to determine and/or monitor at least one of displacement of a drive system or drive assembly coupled to the motor or a force on the motor during actuation of the drive system. For example, a rotary encoder can be coupled to the motor to monitor the rotational position of the motor, thereby monitoring a rotational or linear movement of a respective drive system coupled to the motor. Alternatively or in addition, a torque sensor can be coupled to the motor to determine or monitor an amount of force being applied to the motor during device operation. It is also contemplated that other ways to determine or monitor force on the motor can include (i) measuring current though the motor by using a sensor or a meter device; or (ii) measuring differences between actual velocity of the motor or components, which may include a combination of a distance traveled and an expired time, and the commanded velocity.

In certain embodiments, when the at least one motor is activated, its corresponding rotary motor shaft drives the rotation of at least one corresponding gear assembly located within the drive system of the surgical device. The corresponding gear assembly can be coupled to at least one corresponding drive shaft, thereby causing linear and/or rotational movement of the at least corresponding drive shaft. While movement of two or more drive shafts can overlap during different stages of operation of the drive system, each motor can be activated independently from each other such that movement of each corresponding drive shaft does not necessarily occur at the same time or during the same stage of operation.

When the at least one drive shaft is being driven by its corresponding motor, a rotary encoder, if used, can determine the rotational position of the motor, thereby indicating linear or rotational displacement of the at least one drive shaft. Additionally or in the alternative, when the corresponding motor is activated, the torque sensor, if used, can determine the force on the motor during linear or rotary movement of the at least one drive shaft.

Exemplary motors for use with the systems disclosed herein are described, for example, in U.S. Pat. Nos. 9,445,816 and 9,585,658 and in U.S. Patent Publication Nos. 2012/0292367, 2013/0325034, and 2015/0209059.

Anvil Clamping Drive Assembly

While the anvil clamping drive assembly262can have a variety of configurations, in some implementations, the anvil clamping drive assembly262, as shownFIG. 3, can include a tube gear segment270that is formed on (or attached to) a proximal end220pof the instrument shaft218for operable engagement with a rotational gear assembly. As shown, the rotational gear assembly can include a rotary drive gear272that is in meshing engaging with the tube gear segment270. The rotational gear assembly can also include a rotation drive gear274that is operably coupled to a shaft motor276.

In use, when the shaft motor276is activated, its corresponding rotary motor shaft drives the rotation of the rotational gear assembly, and consequently the tube gear segment270. Activation of the shaft motor276can thus actuate an inner core (not shown) that extends from the tool housing260, through the instrument shaft220, and engages the anvil600at a distal end of the instrument shaft220such that distal advancement of the inner core can move the anvil600distally and proximal retraction of the inner core can move the anvil600proximally so that the anvil600can grasp tissue. Thus the inner core serves to couple with and actuate the anvil600.

It should be noted that in some embodiments, longitudinal slots299of the rotary drive gear272of the anvil clamping drive assembly262can have a length that is equal to or greater than the amount of linear distance the instrument shaft220can move in a distal direction. As a result, the tube gear segment270can slide along the elongated longitudinal slots299, during linear movement of the instrument shaft220without disengagement from the rotary drive gear272. In another embodiment, the tube gear segment270can be engaged with longitudinal slots extending at least partially along the outer surface of the instrument shaft220such that the tube gear segment270can slide along the instrument shaft220when the instrument shaft220moves in distal and proximal directions. In such an embodiment, the rotational gear assembly can also be positioned on a longitudinal shaft that is co-linear with the instrument shaft220to allow the rotational gear assembly to correspondingly slide with the tube gear segment270so that the tube gear segment270and the rotational gear assembly can remain engaged. It is also contemplated that other sliding mechanisms/assemblies can be used to allow corresponding linear movement of at least the tube gear segment270with that of the instrument shaft220.

Outer Staple Drive Assembly

The outer staple drive assembly268can have a variety of configurations. For example, as shown inFIG. 3, the outer staple drive assembly268can include a rotary drive gear296that is in meshing engagement with a rack297A that is coupled to a drive bracket297B having a drive shaft297C extending therefrom and in contact with the proximal end of the outer staple driver750. The rotary drive gear296can be operably coupled to a motor298.

In use, when the motor298is activated by the control system258, its corresponding rotary motor shaft drives the rotation of the rotary drive gear296, thereby causing linear movement of the outer staple driver750. It will be appreciated that the application of a rotary output motion from the motor298in one direction will result in the linear movement of the outer staple driver750in a distal direction to advance an outer row of staples through the distal deployment opening222and deploy staples into tissue (described in detail below). Further, application of the rotary output motion in an opposite direction will result in the linear movement of the outer staple driver750in a proximal direction to retract the outer staple driver750and return the outer staple driver750to its initial position.

Inner Staple Drive Assembly

The inner staple drive assembly264can have a variety of configurations. For example, as shown inFIG. 3, the inner staple drive assembly264can include a rotary drive gear278that is in meshing engagement with a rack280that is coupled to a drive bracket282having a drive shaft284extending therefrom and in contact with the proximal end of the inner stapler driver770. The rotary drive gear278can be operably coupled to a motor286.

In use, when the motor286is activated by the control system258, its corresponding rotary motor shaft drives the rotation of the rotary drive gear278, thereby causing linear movement of the inner stapler driver770. It will be appreciated that the application of a rotary output motion from the motor286in one direction will result in the linear movement of the inner stapler driver770in a distal direction to advance an inner row of staples through the distal deployment opening222and deploy staples into tissue (described in detail below). Further, application of the rotary output motion in an opposite direction will result in the linear movement of the inner stapler driver770in a proximal direction to retract the inner stapler driver770and return the inner stapler driver770to its initial position.

Knife Drive Assembly

The knife drive assembly266can have a variety of configurations. For example, as shown inFIG. 3, the knife drive assembly266can include a rotary drive gear288that is in meshing engagement with a rack290that is coupled to a drive bracket292having a drive shaft294extending therefrom and in contact with the proximal end of the knife assembly710. The rotary drive gear288can be operably coupled to a motor295.

In use, when the motor295is activated by the control system258, its corresponding rotary motor shaft drives the rotation of the rotary drive gear288, thereby causing linear movement of the knife assembly710. It will be appreciated that the application of a rotary output motion from the motor295in one direction will result in the linear movement of the knife assembly710in a distal direction to advance a knife through the distal deployment opening222and through tissue (described in detail below). Further, application of the rotary output motion in an opposite direction will result in the linear movement of the knife assembly710in a proximal direction to retract the knife assembly710and return the knife assembly710to its initial position.

End Effector

As illustrated inFIG. 4, the distal end of the instrument shaft220can have an end effector550with the anvil600, the outer staple driver750, the inner stapler driver770, and the knife assembly710. As best seen inFIG. 5, the anvil600has a head602and a shank614. The head602includes a proximal surface604that defines an outer annular array of staple forming pockets606and an inner annular array of staple forming pockets608. The staple forming pockets606,608are configured to deform staples702as staples702are driven into the staple forming pockets606,608. For instance, each stapling forming pocket606,608can be configured to deform a generally “U” shaped staple702into a “B” shape. The proximal surface604terminates at an inner edge which defines an outer boundary for an annular recess612surrounding the shank614. As will be described in greater detail below, the outer annular array of stapling forming pockets606are configured to receive staples702from a staple deck or cartridge640driven by the outer staple driver750while the inner annular array of staple forming pockets608are configured to receive staples702from the cartridge640driven by the inner staple driver770. An inner cutting surface613faces proximally toward the knife assembly710and is configured to receive a distal-most cutting edge of the knife assembly710thereon to sever tissue. As discussed in more detail below, the inner cutting surface613can have a variety of cutting surfaces or washers formed thereon. An engagement opening616is formed in a proximal end of the shank614and configured to receive the inner core extending from the tool housing260and through the instrument shaft220to allow proximal and distal motion of the anvil600to grasp tissue to be stapled and severed between the anvil600and the cartridge640.

As illustrated inFIG. 6, the cartridge640is configured to be disposed on a distal end of the instrument shaft220and includes a tissue-facing surface642and a plurality of tissue grasping protrusions648. The cartridge640also can have an opening646therethrough, an outer concentric annular array of staple openings644, and an inner concentric annular array of stapling openings645. A plurality of staples702are housed in both staple openings644,645. The staple openings644,645are configured to align with the staple forming pockets606,608, respectively, when the anvil600and the cartridge640compress tissue between the proximal surface604and the tissue-facing surface642. As will be described in greater detail below, the staple openings644,645are configured to receive respective portions of the outer staple driver750and the inner staple driver770to drive staples from the cartridge640and into tissue, and the opening646is configured to receive the knife assembly710therethrough.

As best seen inFIG. 7, the outer staple driver750includes an annular array of staple firing members752, three proximally presented firing legs754each terminating into a drive coupler756. The outer staple driver750defines a bore dimensioned to slidably house the inner staple driver770. The staple firing members752are each dimensioned and configured to actuate within a respective staple opening of outer concentric annular array of staple openings644to drive staples702against a respective staple forming pocket from the outer annular array of staple forming pockets606. The proximally presented firing legs754and respective drive couplers756are configured to selectively align with and couple to a distal-most end of the drive shaft297C such that distal linear movement of the drive shaft297C is configured to advance the outer staple driver750into the cartridge640and fire staples therein into the anvil600independently of both the knife assembly710and the inner staple driver770. Engagement between the firing legs754and respective drive couplers756and the distal-most end of the drive shaft297C can occur in a variety of ways, for example firing pins428can be disposed on the distal-most end of the drive shaft297C to engage the drive couplers756upon distal linear movement.

The inner staple driver770includes a plurality of inner staple driver sections780, each configured to be slidably housed between respective sectors defined by the firing legs754of the outer staple driver750. The inner staple driver sections780define a bore dimensioned to slidably house the knife assembly710, and each inner staple driver section780is located within the bore of the outer staple driver750such that the knife assembly710is nested within the inner staple driver700, which is nested within the outer staple driver750, as illustrated inFIG. 8. Each inner staple driver section780includes a plurality of staple drivers772dimensioned to actuate within a respective staple opening of inner concentric annular array of staple openings645to drive staples702against the inner annular array of staple forming pockets608in the anvil600. Additionally, each inner staple driver section780includes a proximally presented firing leg774with a drive coupler776. The proximally presented firing legs774and the respective drive couplers776are positioned to selectively align with and couple to a distal-most end of the drive shaft284such that distal linear movement of the drive shaft284is configured to advance the inner staple driver770into the cartridge640and fire staples therein into the anvil600independently of both the knife assembly710and the outer staple driver750. Engagement between the firing legs774and the respective drive couplers776and the distal-most end of the drive shaft284can occur in a variety of ways, for example firing pins428can be disposed on the distal-most end of the drive shaft284to engage the drive couplers756upon distal linear movement.

The knife assembly710includes a cylindrical knife member712and a coupling ring730. The cylindrical knife member712includes a distal cutting edge714configured to be received through opening646of the cartridge and configured to sever tissue against the cutting surface613of the anvil600. The coupling ring730also includes three proximally presented firing legs732, each terminating into a drive coupler734. The proximally presented firing legs732and the respective drive couplers734are positioned to selectively align with and couple to a distal-most end of the drive shaft294such that distal linear movement of the drive shaft294is configured to advance the knife assembly710through the cartridge640to reach tissue to be cut against the anvil600independently of both the outer staple driver750and the inner staple driver770. Engagement between the firing legs732and the respective drive couplers734and the distal-most end of the drive shaft294can occur in a variety of ways, for example firing pins428can be disposed on the distal-most end of the drive shaft294to engage the drive couplers734upon distal linear movement.

Stages of Operation

In use, the drive system can have one or more stages of operation. In general, the control system actuates one or more motors for driving movement/action of the drive system for each stage of operation of the drive system. That is, during each stage of operation the control system activates one or more motors to drive the corresponding one or more drive assemblies to effect a rotation and/or linear movement of particular elements of the staple shaft assembly, such as the instrument shaft, the knife, the anvil, and/or each of the inner and outer staple formers, as described below. Thus, movement of the drive system during different stages of operation is controlled by the control system and the operation of the control system will be discussed in more detail below.

Generally, with reference toFIG. 3, actuation of one or more of the motors298,286,295,276will cause longitudinal movement of one or more of the drive shafts297C,284,294, and/or the inner core. Longitudinal movement of one or more of the drive shafts297C,284,294and/or the inner core will cause the one or more drive shafts297C,284,294and/o the inner core to engage with the corresponding outer staple driver750, inner staple driver770, knife assembly710, and/or anvil600. For example, as illustrated inFIG. 9, advancement of the drive shaft297C will cause the firing pins428disposed on a distal-most end of the drive shaft297C to engage the drive coupler756on the outer staple driver750and force the outer staple driver750to move distally to fire staples702from the cartridge640into tissue and against the anvil600.

FIGS. 10-13illustrate one exemplary process for stapling and cutting, however the process can occur in any order.FIG. 10illustrates an initial configuration.FIG. 11illustrates the inner staple driver770being advanced first, firing staples702through tissue641and against the anvil600. The outer staple driver750is advanced next, as shown inFIG. 12, firing staples702against the anvil600. Finally, as shown inFIG. 13, the knife assembly710is fired last to cut tissue with enough force to break a hollow washer711. The washer711can represent a cutting surface, however a variety of cutting surfaces can be used. For example,FIGS. 14 and 15illustrate a hollow washer711and a solid washer713. Alternatively, a cutting surface that is part of the anvil600rather than having a separate washer can be used. The particular cutting surface selected for use will depend on the desired operation of the device, as will be explained below.

A rate of advancement of one or more of the outer staple driver750, inner staple driver770, and/or knife assembly710can be controlled by a variety of factors. For example, the rate can be predetermined, can be set by the control system, can be set by the user, can be based on measured tissue thickness, the type of tissue being grasped, the operation being performed, etc.

The system can control actuation and advancement of the outer staple driver750, inner staple driver770, and/or knife assembly710through a variety of different techniques. The control system can monitor a variety of different parameters to control actuation of each of the various drive assemblies. For example, the control system can monitor force, velocity, displacement, time, etc. Various exemplary techniques are discussed in more detail below.

Tissue Cutting

In one embodiment, the system can control actuation of the knife assembly to determine if tissue has been successfully severed.FIG. 16illustrates a force required to displace each of the inner stapler driver, the outer staple driver, and the knife assembly during operation of the drive system. As shown, the force required to advance the inner staple driver770increases from an initial position to a final position. A first force peak1004is encountered when the inner staple driver770causes staples702to begin to deform from a pre-fired U shape to a B shape. The force will then continue to increase until the staples702are entirely formed to clamp tissue. The outer staple driver750follows a similar force trajectory, encountering an initial force peak1006when the staples702are initially formed from a pre-fired U shape to a B shape, and then continuing to increase. Advancement of both the outer and inner staple drivers750,770can be controlled by controlling displacement of the drivers750,770. In particular, the control system can control the motors to thereby control movement of the outer and inner staple drivers750,770. The ultimate shape of the staples can be controlled by a variety of factors, such as the total amount of displacement of the drivers750,770and the displacement of the anvil600(explained in detail below) relative to the staple cartridge.

As further shown inFIG. 16, the knife assembly710experiences a generally gradually increasing force trajectory as it is advanced to cut tissue. The system can determine when tissue has been cut by monitoring displacement of the knife assembly710from the tool housing260, similar to the outer and inner staple drivers750,770, and it can stop and/or retract the knife assembly710when the knife assembly710reaches a predetermined displacement threshold δCUT, at which point the applied force can rapidly be lowered. Displacement can be monitored through a variety of techniques, for example by using one or more rotary encoders on the motor coupled to the knife assembly710. In such an embodiment, any cutting surface can be used in the anvil600because the system can determine if tissue has been cut by controlling displacement rather than by any behaviors of the cutting surface. The threshold displacement can be a pre-fixed amount or it can be altered by the system and/or a user based on the operation being performed and/or the degree of tissue compression by the anvil600.

The control mechanism illustrated inFIG. 16for controlling cutting is only one example, and a variety of different control mechanisms can be used to control cutting and/or staple advancement.FIG. 17illustrates a rate of change of force over time. The system can monitor the force to advance a drive assembly coupled to one or more of the motors, for example the knife assembly710coupled to motor295for severing tissue. As the knife assembly710is initially advanced, the rate of change of force over time can increase, representing advancing the knife assembly710to encounter tissue to be cut and having a positive slope inFIG. 17. As the knife assembly710is forced into tissue, the rate of change of force over time can become steady, having a slope of zero. As the knife assembly710succeeds in cutting through tissue, the rate of change of force over time can decrease (represented by a negative slope), thus providing an indication to the system that tissue has been cut. The system can either terminate or retract the knife assembly710once it detects that tissue has been cut. In an exemplary embodiment, the system can look for a predetermined threshold change or delta to ensure that tissue has been entirely cut, and the threshold can be a pre-fixed amount or it can be altered by the system and/or a user based on the operation being performed and/or the degree of tissue compression by the anvil600. If an amount of change in force of the knife assembly exceeds the predetermined threshold, the system thereby detects that tissue is fully cut and the system can terminate movement of the knife assembly or cause the knife assembly to retract. Thus when the force required to advance the knife assembly710changes by an amount that exceeds a predetermined threshold or delta, the control system can stop advancement of the knife assembly710.

In another embodiment shown inFIG. 18, the system can monitor force over time, and a predetermined force percentage drop can indicate that cutting has occurred. In particular, as the knife assembly710is advanced into tissue, the amount of applied force can increase and then level off as cutting is taking place. When tissue is successfully cut, however, the applied force will begin to decrease over time because there will no longer be resistance to forward movement of the knife assembly710. If the force drops by a certain amount, the system can detect that cutting has occurred and it can stop forward advancement and/or retract the knife assembly710. The system can thus monitor the force of the knife assembly and if the force drops by a percentage that exceeds a threshold percentage drop, this will indicate that tissue is entirely severed. As with the other thresholds, the threshold can be a pre-fixed amount or it can be altered by the system and/or a user based on the operation being performed and/or the degree of tissue compression by the anvil600.

FIG. 19illustrates another embodiment of a control mechanism that monitors velocity as a function of distance. Initially, the velocity of the knife assembly710can gradually decrease as the knife assembly710is advanced into tissue and begins to cut, since the tissue will cause the knife assembly710to slow down. When the tissue is fully cut, however, there can be a sudden increase in velocity, indicating that there is no longer tissue constraining the knife assembly710. This positive increase can function to indicate to the system that tissue is fully cut, and thus the system can stop forward advancement and/or retract the knife assembly710. The system can thereby monitor the velocity during knife advancement, and if the velocity changes by an amount that exceeds a threshold or delta increase in velocity, this will indicate that the tissue is entirely severed. As with the other thresholds, the threshold can be a pre-fixed amount or can be altered by the system and/or a user based on the operation being performed and/or the degree of tissue compression by the anvil600. Thus when the velocity of the knife assembly710changes by an amount that exceeds a predetermined threshold or delta, the control system can stop advancement of the knife assembly710.

In other aspects, the control system can monitor force applied to the inner staple driver, the outer staple driver, and/or the knife assembly to determine when to cut tissue by advancing the knife assembly and when tissue has been successfully cut and the knife assembly can be safely retracted. Similar toFIG. 16,FIG. 20illustrates force as a function of time as applied to the outer staple driver750, the inner staple driver770, and the knife assembly710. As illustrated inFIG. 20, the system can determine when the knife assembly710is fully advanced and the tissue is fully cut by monitoring the force being applied to the knife assembly710. The control system can monitor force on the knife assembly710over a variety of conditions, such as when using the hollow washer711, when using the solid washer713, and when firing the knife assembly710at different velocities.FIG. 20illustrates the monitored force on the knife assembly710when using the hollow washer711at a first velocity V1shown by dotted line a, illustrates the monitored force on the knife assembly710when using the solid washer713at the first velocity V1shown by dotted line b, and illustrates the monitored force on the knife assembly710when using the hollow washer711at a second velocity V2shown by the solid line c. The control system can determine when to fire the knife assembly710by monitoring force on the inner staple driver770and/or the outer staple driver750. For example, similar to the force inFIG. 16, the force required to advance the inner staple driver770and the outer staple driver750can increase from initial positions, through first force peaks, and then continue to increase until staples are entirely formed. Before staples are entirely formed, the system can begin advancement of the knife assembly710, as illustrated in the dotted lines a, b. The system can also wait until staple formation is complete to begin advancing the knife assembly710, as illustrated by the solid line c. The control system can monitor the force on the knife assembly710, which will steadily increase over time as the knife assembly710is advanced through tissue and encounters a washer. When the knife assembly710encounters a washer, such as the hollow washer711or the solid washer713, the control system will observe a force peak, as can be seen by the solid line c and the dotted lines a, b. The system can determine when tissue is entirely cut by detecting an initial decrease in the monitored force. For example, when the knife assembly710breaks through the hollow washer711, the force on the knife assembly710will decrease immediately, as can be seen by the solid line c and the dotted line a. When the knife assembly710cuts through tissue and encounters the solid washer, the force can experience a stepped-down decrease. The control system can thus detect that tissue is entirely cut by monitoring force on the knife assembly710. When the knife assembly710is fired at a faster velocity V2in comparison to velocity V1, the knife assembly710is able to cut through tissue and break the washer711with less force, as can be seen in the lower force curve of the solid line c ofFIG. 20when compared to the dotted lines a, b. The greater impulse impact from the higher velocity means that less force is required to break through tissue and the washer711.

The control system can also control firing of the different drive assemblies based on timing. The control system can have predetermined time offsets that it uses to determine when to begin advancing the inner staple driver770, the outer staple driver750, and the knife assembly710based on predetermined time offsets from previous steps.FIG. 21illustrates a graph showing force as a function of time as applied to the outer staple driver750, the inner staple driver770, and the knife assembly710. InFIG. 21, the control system advances the inner staple driver770first, and the control system advances the outer staple driver750after a first offset O1of time from the advancement of the inner staple driver770. The control system can determine when the staples of the inner circular row are completely formed by the inner staple driver770by waiting a second offset O2of time from advancement of the outer staple driver750. The control system can wait a third offset O3of time from the completed formation of the inner staples, at which point the control system can begin advancing the knife assembly710. While the knife assembly710is being advanced, formation of staples in the outer row of staples is completed by the outer staple driver750. The control system can then determine when tissue has been completely cut and the knife assembly710should be retracted by waiting a fourth offset O4of time from when the outer staples are formed, represented by the peak of the force curve of the knife assembly710(V1represents the velocity of the knife assembly710). The control system can thus use various timing offsets to control advancement of one or more of the inner staple driver770, the outer staple driver750, and/or the knife assembly710based on various previous steps in the stapling and cutting process. The offsets can be predetermined or can be changed by the system and/or the user.

Anvil Closing

In other aspects, the control system can monitor the force and velocity on an anvil and use that information to control actuation of each drive assembly.FIG. 22illustrates three stages of operation of the drive system257, and in particular section A ofFIG. 22illustrates force applied to tissue as a function of displacement of the anvil, for example anvil600, during each stage of operation. Section B ofFIG. 22illustrates velocity of the anvil as a function of displacement.

During the first stage, the control system can monitor the force or velocity during closing of the anvil600to detect if an error has occurred. In the first stage, the anvil600experiences a quick close operation to rapidly grasp tissue, for example by grasping tissue between the anvil600and the cartridge640. While the circular stapler anvil600and the cartridge640will be discussed herein, the three stages of operation of the drive system can be applied to any tissue-clamping device. During stage one, the anvil600is rapidly closed and is therefore displaced by a first distance, e.g., approximately 1.7 inches in the illustrated embodiment. However, there are at least two situations where the drive system can determine that a malfunction has occurred. If an error has occurred, such as an obstruction preventing proper closure of the anvil600, the force will spike, as shown in section A. If the force being applied to the anvil600exceeds a predetermined threshold FT1during displacement of the anvil in the first stage, the system can determine that an error has occurred and the system can stop the clamping action of the anvil600. As shown in section B, if an error has occurred, the velocity of the anvil600will rapidly decline during the first stage. The system can thus monitor force and/or velocity changes to detect if an error has occurred. Alternatively, if the force being applied declines suddenly, the system can likewise determine that an error has occurred, such as the anvil600becoming loose from the device. This is shown inFIG. 23. If the force drops by an amount that exceeds a predetermined threshold rate Fdrop(from a force at point1to a force at point2inFIG. 23), the system can determine that the anvil600might have popped off of the device. The system can stop the clamping action of the anvil600and/or reverse the clamping process. As shown in section A ofFIG. 22, this is represented by a rapid decline in the force curve. As shown in section B, this can also be represented by a rapid decline in the velocity of the anvil600.

During the second stage, tissue continues to be compressed by the anvil600. The anvil600approaches an optimal compression level of the tissue during this stage, as can be seen by the force curve in section A approaching the threshold FT2, representing the optimum compression. The system can monitor the force to move the anvil, and once the force exceeds the threshold FT2, the system can allow staples to be fired. Also during this stage, as illustrated in section B, the velocity of the anvil will slow down to allow for a better compression of tissue grasped during the quick close of the first stage. In an exemplary embodiment, optimum compression can occur at an anvil displacement of at least approximately 3.1 inches.

During the third stage, staple formation occurs. Force on the anvil600can increase as the staples are fully formed, and the velocity of the anvil can decline and/or stop entirely once the optimum compression is reached, as selected by the user, and the tissue does not need further clamping.

Because the control system can monitor and determine the displacement of the anvil600, the control system can determine a gap size between the anvil600and the cartridge640. The control system can use this information to determine a thickness of the tissue grasped by the anvil600. The control system can alter the distance that the inner staple drive assembly770, the outer staple drive assembly750, and the knife assembly710are advanced based on the gap size or thickness of the tissue between the anvil600and the cartridge640. For example, the inner staple drive assembly770, the outer staple drive assembly750, and/or the knife assembly710can be advanced farther when the system determines that the grasped tissue is thick. The control system can also alter the rates of advancement of one or more of the inner staple drive assembly770, the outer staple drive assembly750, and the knife assembly710based on the thickness of the tissue engaged between the anvil600and the cartridge640. As the tissue thickness increases, the system can reduce the rates of advancement of one or more of the inner staple drive assembly770, the outer staple drive assembly750, and the knife assembly710to compensate for the thicker tissue.

Staple Formation

The control system can also monitor and control the position of the anvil to form the staple to a desired shape, such as a high “B” or a low “B”.FIG. 24illustrates three stages of operation of the drive system during anvil displacement to control staple formation, and in particular section A ofFIG. 24illustrates force applied to tissue as a function of displacement of the anvil600to clamp tissue during each stage of operation. Section B ofFIG. 24illustrates a velocity of the anvil as a function of displacement. The control system can control the velocity of the anvil600based on the displacement of the anvil600in order to achieve the desired compression of clamped tissue. During the first stage, which is a quick close stage as inFIG. 22, the control system can monitor the force on and the displacement of the anvil600, and the control system can control the velocity of the anvil600as it is rapidly displaced. The force begins to rise as the anvil approaches approximately a first distance, e.g., 1.7 inches of displacement in the illustrated embodiment. An initial increase in the force will indicate to the system that the anvil600has made contact with tissue, as illustrated in section A. Section B illustrates the rapid but constant velocity of the anvil600as the anvil closes on tissue. During the second stage, the tissue continues to be compressed by the anvil600. The force will exceed an overload threshold value, thereby causing the control system to focus on load control of the force being applied to the tissue to reach an optimum compression. The velocity of the anvil during this stage experiences a stepped-down decline as the quick close stage ends and the slower tissue clamping occurs. At the end of the second stage, the displacement of the anvil600approaches approximately 3.1 inches, in the illustrated embodiment. When displacement of the anvil is at approximately 3.1 inches, the system can allow firing of staples to form High “B” staples, as illustrated on the graph inFIG. 24. High “B” staples are staples in which the legs of the staple have begun to curl back toward the base of the staple but have not reached the base of the staple. High “B” staples can be used when a user or the system desires less compression and therefore a less-compressed staple. If a user and/or the system desire this level of compression, displacement of the anvil600can be stopped at this point and the force can remain constant while the velocity falls to zero. However, compression can be increased up to 3.4 inches of displacement, at which point the staples will be formed into Low “B” staples, as illustrated on the graph inFIG. 24. Low “B” staples are staples in which the legs of the staple are curled back toward the base of the staple and cross over the base of the staple to form a very compressed staple. Low “B” staples can be used when a user or the system desires a greater level of compression and thus a more compressed staple relative to the High “B” staples. If a user and/or the system desire this level of compression, displacement of the anvil600can be continued until the desired level of compression is reached, causing the force to increase and the velocity to continue at a constant level until the desired compression is reached. A preferred compression zone can be between approximately 3.1 inches of displacement and 3.4 inches of displacement, and the compression level can be predetermined, set by the system, and/or set by the user depending on the operation to be performed and tissue to be grasped. Accordingly, the system can control staple formation by controlling the velocity of the anvil to achieve a desired displacement of the anvil.

For each stage of operation there can be at least one predetermined motor force threshold and/or a displacement threshold determined by current monitor(s), rotary encoder(s), etc. (as discussed above).

Operation of Control System

Generally, as discussed above, the control system can control movement and actuation of a surgical device. For example, the control system can include at least one computer system and can be operably coupled to the at least one motor that drives a drive system on the surgical device. The computer system can include components, such as a processor, that are configured for running one or more logic functions, such as with respect to a program stored in a memory coupled to the processor. For example, the processor can be coupled to one or more wireless or wired user input devices (“UIDs”), and it can be configured for receiving sensed information, aggregating it, and computing outputs based at least in part on the sensed information. These outputs can be transmitted to the drive system of surgical device to control the surgical device during use.

In certain embodiments, the control system can be a closed-loop feedback system. The stored data within the computer system can include predetermined threshold(s) for one or more stages of operation of the drive system. When the control system is actuated, it drives one or more motors on or coupled to the surgical device, consequently actuating the drive system through each stage of operation. During each stage of operation, the control system can receive feedback input from one or more sensors coupled to the motor(s) that sense displacement and/or torque of the motor(s). The computer system can aggregate the received feedback input(s), perform any necessary calculations, compare it to the predetermined threshold for the corresponding stage of operation, and provide output data to the motor(s). If at any time during each stage of operation the control system determines that the received input exceeds a maximum predetermined threshold or is less than a minimum predetermined threshold, the control system can modify the output data sent to the motor based on the programmed logic functions. For example, the control system can modify the output data sent to the motor(s) to reduce a current delivered to the motor to reduce motor force or a voltage delivered to the motor to thereby reduce a rotational speed of the motor(s) or to stop movement of the motor(s).

Referring back toFIGS. 2 and 3, the control system258, which includes at least one computer system, can be operably coupled (wired or wirelessly) to each of the motors276,286,295,298that drive the various components of the drive system257. As described above, for each stage of operation one or more motors276,286,295,298are actuated by the control system258. As a result, the control system258can control the movement of at least one of the instrument shaft220, the pusher234, the anvil228, and the staple former226. In particular, the control system258can monitor a force required to move each of the outer staple driver, the inner staple driver, the anvil, and the knife assembly during each stage of operation, can compare the monitored force to various threshold forces, and can modify or terminate current applied to the motor to thereby modify or terminate movement of the anvil, staple drivers, and/or knife assembly.

In other embodiments, mechanical stops can be used to control displacement of the staple drivers, anvil, and/or the knife assembly during each stage of operation. That is, rather programming the computer system with displacement data, as described above, one or more mechanical stops can be used to control displacement during each stage of operation. Thus, the control system can modify the output data sent to the motors to cease movement (or in the alternative, reduce current to the motor to reduce motor speed) when a mechanical stop is engaged (as would be indicated by a force spike) or the force applied by a motor exceeds a predetermined threshold.

In other embodiments, for each stage of operation, the control system can control the force applied by each motor based on predetermined motor force thresholds and can monitor the displacement once these thresholds have been met. That is, during each stage of operation, when the control system determines that the predetermined motor force(s) have been met, the control system can then measure the displacement to determine the position of the staple drivers, anvil, and/or knife assembly.

As discussed above, the control system disclosed herein can be implemented using one or more computer systems, which may also be referred to herein as digital data processing systems and programmable systems.

FIG. 25illustrates one exemplary embodiment of a computer system800. As shown, the computer system800includes one or more processors802which can control the operation of the computer system800. “Processors” are also referred to herein as “controllers.” The processor(s)802can include any type of microprocessor or central processing unit (CPU), including programmable general-purpose or special-purpose microprocessors and/or any one of a variety of proprietary or commercially available single or multi-processor systems. The computer system800can also include one or more memories804, which can provide temporary storage for code to be executed by the processor(s)802or for data acquired from one or more users, storage devices, and/or databases. The memory804can include read-only memory (ROM), flash memory, one or more varieties of random access memory (RAM) (e.g., static RAM (SRAM), dynamic RAM (DRAM), or synchronous DRAM (SDRAM)), and/or a combination of memory technologies.

The various elements of the computer system800can be coupled to a bus system812. The illustrated bus system812is an abstraction that represents any one or more separate physical busses, communication lines/interfaces, and/or multi-drop or point-to-point connections, connected by appropriate bridges, adapters, and/or controllers. The computer system800can also include one or more network interface(s)806, one or more input/output (IO) interface(s)808that can include one or more interface components, and one or more storage device(s)810.

The network interface(s)806can enable the computer system800to communicate with remote devices, e.g., motor(s) coupled to the drive system257that is located within the surgical device or a robotic surgical system or other computer systems, over a network, and can be, for non-limiting example, remote desktop connection interfaces, Ethernet adapters, and/or other local area network (LAN) adapters. The IO interface(s)808can include one or more interface components to connect the computer system800with other electronic equipment, such as the sensors located on the motor(s). For non-limiting example, the IO interface(s)808can include high speed data ports, such as universal serial bus (USB) ports, 1394 ports, Wi-Fi, Bluetooth, etc. Additionally, the computer system800can be accessible to a human user, and thus the IO interface(s)808can include displays, speakers, keyboards, pointing devices, and/or various other video, audio, or alphanumeric interfaces. The storage device(s)810can include any conventional medium for storing data in a non-volatile and/or non-transient manner. The storage device(s)810can thus hold data and/or instructions in a persistent state, i.e., the value(s) are retained despite interruption of power to the computer system800. The storage device(s)810can include one or more hard disk drives, flash drives, USB drives, optical drives, various media cards, diskettes, compact discs, and/or any combination thereof and can be directly connected to the computer system800or remotely connected thereto, such as over a network. In an exemplary embodiment, the storage device(s)810can include a tangible or non-transitory computer readable medium configured to store data, e.g., a hard disk drive, a flash drive, a USB drive, an optical drive, a media card, a diskette, a compact disc, etc.

The elements illustrated inFIG. 25can be some or all of the elements of a single physical machine. In addition, not all of the illustrated elements need to be located on or in the same physical machine. Exemplary computer systems include conventional desktop computers, workstations, minicomputers, laptop computers, tablet computers, personal digital assistants (PDAs), mobile phones, and the like.

The computer system800can include a web browser for retrieving web pages or other markup language streams, presenting those pages and/or streams (visually, aurally, or otherwise), executing scripts, controls and other code on those pages/streams, accepting user input with respect to those pages/streams (e.g., for purposes of completing input fields), issuing HyperText Transfer Protocol (HTTP) requests with respect to those pages/streams or otherwise (e.g., for submitting to a server information from the completed input fields), and so forth. The web pages or other markup language can be in HyperText Markup Language (HTML) or other conventional forms, including embedded Extensible Markup Language (XML), scripts, controls, and so forth. The computer system800can also include a web server for generating and/or delivering the web pages to client computer systems.

In an exemplary embodiment, the computer system800can be provided as a single unit, e.g., as a single server, as a single tower, contained within a single housing, etc. The single unit can be modular such that various aspects thereof can be swapped in and out as needed for, e.g., upgrade, replacement, maintenance, etc., without interrupting functionality of any other aspects of the system. The single unit can thus also be scalable with the ability to be added to as additional modules and/or additional functionality of existing modules are desired and/or improved upon.

A computer system can also include any of a variety of other software and/or hardware components, including by way of non-limiting example, operating systems and database management systems. Although an exemplary computer system is depicted and described herein, it will be appreciated that this is for sake of generality and convenience. In other embodiments, the computer system may differ in architecture and operation from that shown and described here.