Method for controlling the actuation of a cutting member of a powered surgical stapler - Patent Application 20070122997

Abstract

A method is provided for operating a powered surgical stapler having a motor unit, a controller, and a stapling assembly having a closure member, a staple driver member, and a knife member. The controller receives user input indicating a tissue gap defined by the stapling assembly in a closed state. Based on the user input, the controller controls the motor unit to actuate the closure member to transition the stapling assembly to the closed state, defining the tissue gap and clamping tissue therein. The controller then controls the motor unit to actuate the staple driver member to drive staples into the clamped tissue. In response to determining that the staple driver member has reached a predetermined longitudinal position, the controller controls the motor unit to initiate actuation of the knife member to sever the clamped tissue.

Description

[Background technology]

[0001] In some surgical procedures (e.g., colorectal surgery, bariatric surgery, thoracic surgery, etc.), a portion of a patient's digestive tract (e.g., gastrointestinal tract and / or esophagus) may be resected to remove unwanted tissue or for other reasons. After the tissue is removed, the remaining portions of the digestive tract can be reconnected to one another using an end-to-end, end-to-side, or side-to-side anastomosis. The anastomosis can provide a substantially unobstructed flow path from one portion of the digestive tract to another portion of the digestive tract without leakage of any kind from the anastomosis site.

[0002] One example of an instrument that can be used to provide an anastomosis is a circular stapler. Some such staplers are operable to clamp layers of tissue, sever the clamped tissue layers, and drive staples through the clamped tissue layers to substantially seal the tissue to one another adjacent the severed ends of the tissue layers and join the two severed ends of the anatomical lumen. Circular staplers can be configured to sever tissue and substantially simultaneously seal the tissue. For example, circular staplers can sever excess tissue medial to the annular array of staples at the anastomosis to provide a substantially smooth transition between the anatomical lumens joined at the anastomosis. Circular staplers can be used in open or endoscopic surgery. In some cases, a portion of the circular stapler is inserted through an existing opening in the patient's body.

[0003] Examples of circular staplers are U.S. Pat. No. 5,205,459, issued April 27, 1993, entitled "Surgical Anastomosis Stapling Instrument"; U.S. Pat. No. 5,271,544, issued December 21, 1993, entitled "Surgical Anastomosis Stapling Instrument"; U.S. Pat. No. 5,275,322, issued January 4, 1994, entitled "Surgical Anastomosis Stapling Instrument"; U.S. Pat. No. 5,285,945, issued February 15, 1994, entitled "Surgical Anastomosis Stapling Instrument"; and U.S. Pat. No. 5,292,053, issued March 8, 1994, entitled "Surgical Anastomosis Stapling Instrument." No. 5,333,773, issued August 2, 1994, entitled "Surgical Anastomosis Stapling Instrument"; U.S. Patent No. 5,350,104, issued September 27, 1994, entitled "Surgical Anastomosis Stapling Instrument"; U.S. Patent No. 5,533,661, issued July 9, 1996, entitled "Surgical Anastomosis Stapling Instrument"; and U.S. Patent No. 8,910,847, issued December 16, 2014, entitled "Low Cost Anvil Assembly for a Circular Stapler." The disclosures of each of the above-cited U.S. patents are incorporated herein by reference.

[0004] Some circular staplers may include a powered actuation mechanism. Examples of circular staplers with motorized actuation mechanisms are described in U.S. Patent Application Publication No. 2015 / 0083772, published March 26, 2015, entitled "Surgical Stapler with Rotary Cam Drive and Return," the disclosures of which are incorporated herein by reference; U.S. Patent Application Publication No. 2015 / 0083773, published March 26, 2015, entitled "Surgical Stapling Instrument with Drive Assembly Having Toggle Features," the disclosures of which are incorporated herein by reference; U.S. Patent Application Publication No. 2015 / 0083774, published March 26, 2015, entitled "Control Features for Motorized Surgical Stapling Instrument," and U.S. Patent Application Publication No. 2015 / 0083775, published March 26, 2015, entitled "Surgical Stapler with Rotary Cam Drive," the disclosures of which are incorporated herein by reference. The disclosure of each of the above-cited US patent application publications is incorporated herein by reference.

[0005] While many different types of surgical stapling instruments and related components have been made and used, it is believed that no one prior to the present inventors has made or used the invention as set forth in the appended claims. [Brief explanation of the drawings]

[0006] While this specification concludes with claims particularly pointing out and distinctly claiming the present technology, it is believed that the present technology will be better understood from the following description of certain specific embodiments read in conjunction with the accompanying drawings, in which like reference numerals identify the same elements. [Figure 1] FIG. 1 is a perspective view of an exemplary circular surgical stapler. [Figure 2]2 is a perspective view of the circular stapler of FIG. 1 with the battery pack removed from the handle assembly and the anvil removed from the stapling head assembly; [Figure 3] FIG. 2 is a perspective view of the anvil of the circular stapler of FIG. 1; [Figure 4] FIG. 2 is a perspective view of a stapling head assembly of the circular stapler of FIG. 1; [Figure 5] FIG. 5 is an exploded perspective view of the stapling head assembly of FIG. 4; [Figure 6] 2 is an exploded perspective view of the circular stapler of FIG. 1, showing portions of the shaft assembly separated from one another; FIG. [Figure 7A] FIG. 5 is a cross-sectional side view of the anvil of FIG. 3 positioned in a first section of the digestive tract and the stapling head assembly of FIG. 4 positioned in a second section of the digestive tract, with the anvil separated from the stapling head assembly. [Figure 7B] FIG. 5 is a cross-sectional side view of the anvil of FIG. 3 positioned in a first section of the digestive tract and the stapling head assembly of FIG. 4 positioned in a second section of the digestive tract, with the anvil secured to the stapling head assembly; [Figure 7C] FIG. 5 is a cross-sectional side view of the anvil of FIG. 3 positioned in a first section of the digestive tract and the stapling head assembly of FIG. 4 positioned in a second section of the digestive tract, with the anvil retracted toward the stapling head assembly, thereby clamping tissue between the anvil and the stapling head assembly. [Figure 7D] FIG. 5 is a cross-sectional side view of the anvil of FIG. 3 positioned in a first section of the digestive tract and the stapling head assembly of FIG. 4 positioned in a second section of the digestive tract, with the stapling head assembly actuated to cut and staple clamped tissue; [Figure 7E] 7B is a cross-sectional side view showing the first and second segments of the digestive tract of FIG. 7A joined together in an end-to-end anastomosis. [Figure 8]FIG. 2 is a perspective view of a user interface mechanism of the handle assembly of the circular stapler of FIG. 1; [Figure 9] FIG. 10 is a perspective view of another exemplary circular surgical stapler. [Figure 10] 10 is a schematic diagram of the circular stapler of FIG. 9, including a control system for the circular surgical stapler. [Figure 11] 11 is a schematic diagram of an exemplary method for controlling the circular surgical stapler of FIG. 9 via the control system of FIG. 10. [Figure 12] 11 is a schematic diagram of an exemplary method for calibrating the actuation stroke of the movable member of the circular stapler of FIG. 9 by adjusting the actuation algorithm executed by the control system of FIG. 10. [Figure 13A] 10 is a schematic cross-sectional view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9 showing the anvil in a fully open position relative to the stapling head assembly; [Figure 13B] 10 is a schematic cross-sectional view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9 showing the anvil in a partially closed position relative to the stapling head assembly; [Figure 13C] 10 is a schematic cross-sectional view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9 showing the anvil in a fully closed position relative to the stapling head assembly; [Figure 14] 10 is a schematic cross-sectional view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9 showing the anvil in a fully closed position relative to the staple retainers of the stapling head assembly; [Figure 15] FIG. 10 shows a line graph of the longitudinal displacement of the anvil of the circular surgical stapler of FIG. 9 from a fully open position to a fully closed position and back to the fully open position, illustrating the calibration of the anvil stroke after closure and before reopening. [Figure 16]10 is a schematic diagram of a graphical indicator of the user interface mechanism of the circular surgical stapler of FIG. 9 showing exemplary first and second tissue gap settings relative to the anvil. [Figure 17A] 17 is a schematic side view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9, showing the anvil positioned to define a larger first tissue gap corresponding to the first tissue gap setting of FIG. 16; [Figure 17B] 17 is a schematic side view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9, showing the anvil positioned to define a smaller second tissue gap corresponding to the second tissue gap setting of FIG. 16; [Figure 18] FIG. 10 is a schematic side view of the stapling head assembly and anvil of the circular surgical stapler of FIG. 9 showing the staple driver and staples in a fully recessed position with lateral portions cut away to reveal corresponding staples housed within the respective staple openings. [Figure 19A] FIG. 19 is a side view of the staple driver and staple of FIG. 18, showing the staple driver and staple in a fully recessed proximal position; [Figure 19B] FIG. 19 is a side view of the staple driver and staple of FIG. 18, showing the staple driver and staple in a partially extended intermediate position in which the top end of the staple driver and the crown of the staple are positioned on the deck surface of the stapling head assembly and staple. [Figure 19C] 19 is a side view of the staple driver and staple of FIG. 18, showing the staple driver and staple in a fully extended distal position in which the staple legs are fully formed by the anvil. [Figure 20] 10 is a line graph illustrating exemplary relationships between operating elements of the circular stapler of FIG. 9 over time, including anvil displacement, knife displacement, and firing load on the motor unit. [Figure 21] 10 is a line graph illustrating firing load over time for the circular surgical stapler of FIG. 9 with two different firing algorithms.

[0007] The drawings are not intended to be limiting in any manner, and it is contemplated that various embodiments of the technology may be embodied in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of the technology and, together with the description, serve to explain the principles of the technology, although it is understood that the technology is not limited to the precise arrangements shown. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following description of specific examples of the present technology should not be used to limit its scope. Other examples, features, aspects, embodiments, and advantages of the present technology will become apparent to those skilled in the art from the following description, which is, by way of example, one of the best modes contemplated for carrying out the present technology. As will be understood, the technology described herein is capable of other different and obvious aspects, all without departing from the technology. Therefore, the drawings and descriptions should be regarded as illustrative in nature, and not as restrictive.

[0009] For clarity of this disclosure, the terms "proximal" and "distal" are defined herein relative to a surgeon or other operator grasping a surgical instrument having a distal surgical end effector. The term "proximal" refers to the location of elements disposed closer to the surgeon, and the term "distal" refers to the location of elements disposed closer to the surgical end effector of the surgical instrument and farther from the surgeon. Also, to the extent spatial terms such as "top," "bottom," "upper," "lower," "vertical," and "horizontal" are used herein with reference to the drawings, it will be understood that such terms are used for illustrative descriptive purposes only and are not intended to be limiting or absolute. In that regard, it will be understood that surgical instruments such as those disclosed herein may be used in a variety of orientations and positions, not limited to those shown and described herein.

[0010] I. Overview of an Exemplary Circular Surgical Stapling Instrument 1-2 illustrate an exemplary circular surgical stapling instrument (10) that may be used to provide end-to-end, side-to-side, or end-to-side anastomosis between two cross-sections of an anatomical lumen, such as a portion of a patient's digestive tract. The instrument (10) in this example includes a body assembly (e.g., handle assembly (100)), a shaft assembly (200) extending distally from the handle assembly (100), a stapling head assembly (300) at the distal end of the shaft assembly (200), and an anvil (400) configured to releasably couple to and cooperate with the stapling head assembly (300) to clamp, staple, and sever tissue. The instrument (10) further includes a removable battery pack (120) operable to power a motor (160) housed within the handle assembly (100), as described in more detail below.

[0011] The shaft assembly (200) extends distally from the handle assembly (100) and includes a pre-formed bend. In some variations, the pre-formed bend is configured to facilitate positioning the stapling head assembly (300) within the patient's colon. A variety of suitable bend angles or radii of curvature that may be used will be apparent to those skilled in the art in view of the teachings herein. In some other variations, the shaft assembly (200) is straight, and the shaft assembly (200) does not include a pre-formed bend. Various exemplary components may be incorporated into the shaft assembly (200), as will be described in more detail below.

[0012] The stapling head assembly (300) is disposed at the distal end of the shaft assembly (200). As shown in FIGS. 1-2 and described in more detail below, the anvil (400) is configured to be removably coupled to the shaft assembly (200) adjacent to the stapling head assembly (300). As also described in more detail below, the anvil (400) and the stapling head assembly (300) are configured to cooperate to manipulate tissue in three ways, including clamping tissue, cutting tissue, and stapling tissue. A knob (130) at the proximal end of the handle assembly (100) is rotatable relative to the casing (110) to allow precise clamping of tissue between the anvil (400) and the stapling head assembly (300). When the safety trigger (140) of the handle assembly (100) is pivoted away from the firing trigger (150) of the handle assembly (100), the firing trigger (150) can be actuated such that tissue is cut and stapled.

[0013] A. Exemplary Anvil As best seen in FIG. 3 , the anvil (400) of this embodiment includes a head (410) and a shank (420). The head (410) includes a proximal surface (412) that defines a plurality of staple-forming pockets (414). The staple-forming pockets (414) are arranged in two concentric annular arrays in this embodiment. In some other variations, the staple-forming pockets (414) are arranged in three or more concentric annular arrays. The staple-forming pockets (414) are configured to deform the staples as they are driven into the staple-forming pockets (414). For example, each staple-forming pocket (414) may deform a generally U-shaped staple into a B-shape, as is known in the art. The proximal surface (412) terminates in an inner edge (416), which defines the outer boundary of an annular recess (418) that circumscribes the shank (420).

[0014] The shank 420 defines a bore 422 and includes a pair of pivoting latch members 430. The latch members 430 are positioned within the bore 422 such that their distal ends 434 are positioned at the proximal ends of lateral openings 424 formed through the sidewall of the shank 420. The lateral openings 424 thus provide clearance for the distal end 434 and the latch shelf 436 to deflect radially outward from the longitudinal axis defined by the shank 420. However, the latch members 430 are configured to resiliently bias the distal end 434 and the latch shelf 436 to pivot radially inward toward the longitudinal axis defined by the shank 420. In this manner, the latch members 430 act as retaining clips. This allows the anvil (400) to be removably secured to an actuatable closure member in the form of a trocar (330) of the stapling head assembly (300), as will be described in more detail below. However, it should be understood that the latch member (436) is merely optional. The anvil (400) may be removably secured to the trocar (330) using any other suitable components, mechanisms, or techniques.

[0015] B. Exemplary Stapling Head Assembly As best shown in Figures 4 and 5, the stapling head assembly (300) of this embodiment is coupled to the distal end of the shaft assembly (200) and includes a body member (310) and a staple driver member (350) slidably received therein. The body member (310) includes a distally extending cylindrical inner core member (312). The body member (310) is fixedly secured to the outer sheath (210) of the shaft assembly (200), such that the body member (310) and the outer sheath (210) together function as a mechanical ground for the stapling head assembly (300). In some variations, the stapling head assembly (300) may be configured to be releasably coupled to the distal end of the shaft assembly (200), as disclosed, for example, in U.S. Patent No. 9,597,081, issued March 21, 2017, entitled "Motor Driven Rotary Input Circular Stapler with Modular End Effector," the disclosure of which is incorporated herein by reference.

[0016] The trocar (330) is coaxially positioned within the inner core member (312) of the body member (310). As will be described in more detail below, the trocar (330) is operable to translate distally and proximally relative to the body member (310) in response to rotation of the knob (130) relative to the casing (110) of the handle assembly (100). The trocar (330) comprises a shaft (332) and a head (334). The head (334) includes a pointed tip (336) and an inwardly extending proximal surface (338). Thus, the shaft (332) has a reduced outer diameter just proximal to the head (334), with the surface (338) providing a transition between the reduced outer diameter of the shaft (332) and the outer diameter of the head (334). In this embodiment, the tip 336 is pointed, but not sharp. Therefore, the tip 336 does not easily cause trauma to tissue through accidental contact with the tissue. The head 334 and the distal portion of the shaft 332 are configured to be inserted into the bore 422 of the anvil 400. The proximal surface 338 and the latch shelf 436 have a complementary position and configuration such that the latch shelf 436 engages the proximal surface 338 when the shank 420 of the anvil 400 is fully seated on the trocar 330. Thus, the anvil 400 is secured to the trocar 330 via a snap fit provided by the latch member 430.

[0017] The staple driver member (350) is operable to actuate longitudinally within the body member (310) in response to activation of the motor (160), as will be described in more detail below. The staple driver member (350) of this embodiment includes two concentric annular arrays of staple drivers (352) presented distally. The staple drivers (352) are arranged to correspond to the arrangement of the staple forming pockets (414) of the anvil (400). Accordingly, each staple driver (352) is configured to drive a corresponding staple into the corresponding staple forming pocket (414) upon actuation of the stapling head assembly (300). It should be understood that the arrangement of the staple drivers (352) and staple forming pockets (414) shown herein may be modified in any suitable manner, provided that the staple drivers (352) and staple forming pockets (414) are configured to align with one another to effect proper formation of staples. Staple driver member (350) also defines a bore (354) configured to coaxially receive core member (312) of body member (310). An annular array of studs (356) protrudes distally from a distally presented surface surrounding bore (354).

[0018] A cylindrical knife member (340) is coaxially positioned within the staple driver member (350). The knife member (340) includes a sharp, circular cutting edge (342) presented distally. The knife member (340) is sized such that the knife member (340) defines an outer diameter that is smaller than the diameter defined by the inner annular array of staple drivers (352). The knife member (340) also defines an opening configured to coaxially receive the core member (312) of the body member (310). The annular array of openings (346) formed in the knife member (340) is configured to complement the annular array of studs (356) of the staple driver member (350), such that the knife member (340) is fixedly secured to the staple driver member (350) via the studs (356) and the openings (346). By way of example only, stud 356 may be heat staked to knife member 340 using techniques known in the art. Other suitable structural relationships between knife member 340 and staple driver member 350 will be apparent to those skilled in the art in view of the teachings herein.

[0019] A deck member (320) is fixedly secured to the distal end of the body member (310). The deck member (320) includes a distally directed deck surface (322) that defines two concentric annular arrays of staple openings (324). The staple openings (324) are arranged to correspond to the arrangement of the staple drivers (352) and staple forming pockets (414) described above. Accordingly, each staple opening (324) is configured to provide a path for a corresponding staple driver (352) to drive a corresponding staple through the deck member (320) and into the corresponding staple forming pocket (414) when the stapling head assembly (300) is actuated. It should be understood that the arrangement of the staple openings (324) can be modified to correspond to the arrangement of the drivers (352) and staple forming pockets (414) described above. It should also be understood that a variety of structures and techniques may be used to contain the staples within the stapling head assembly (300) before the stapling head assembly (300) is actuated. Such structures and techniques used to contain the staples within the stapling head assembly (300) may prevent the staples from inadvertently dropping out of the staple openings (324) before the stapling head assembly (300) is actuated. The various suitable forms that such structures and techniques may take will be apparent to those skilled in the art in view of the teachings herein.

[0020] As best shown in Figure 9, deck member (320) defines an inner diameter that is only slightly larger than the outer diameter defined by knife member (340). Accordingly, deck member (320) is configured to allow knife member (340) to translate distally to a point where cutting edge (342) is distal to deck surface (322).

[0021] In some variations of the instrument (10), it may be desirable to provide the instrument (10) with features configured to indicate proper and / or improper coupling of the anvil (400) of the stapling head assembly (300) to the trocar (330). For example, if the anvil (400) is not properly coupled to the trocar (330), the operator may receive audible and / or tactile feedback indicating improper coupling. Furthermore, if the anvil (400) is properly coupled to the trocar (330), the operator may receive audible, tactile, and / or visual feedback indicating proper coupling. Additionally or alternatively, structure may be configured to prevent firing of the stapling head assembly (300) unless the anvil (400) is properly coupled to the trocar (330). For example, if the anvil (400) is not properly coupled to the trocar (330), the stapling head assembly (300) may be prevented from firing. When the anvil (400) is properly coupled to the trocar (330), firing of the stapling head assembly (300) may be possible. Such mechanisms may include various types of visual indicia, sensors, switches, etc. By way of example only, such mechanisms may include those of the type disclosed in U.S. Patent No. 10,307,157, issued June 4, 2019, entitled "Surgical Stapler with Analis Seation Detection," and U.S. Patent Application Publication No. 2017 / 0258471, published September 14, 2017, entitled "Methods and Systems for Performing Circular Stapling," the disclosure of which is incorporated herein by reference.

[0022] C. Typical Shaft Assembly 6 illustrates various components of shaft assembly (200), which couples components of stapling head assembly (300) to components of handle assembly (100). In particular, and as noted above, shaft assembly (200) includes outer sheath (210) that extends between handle assembly (100) and body member (310). In this embodiment, outer sheath (210) is rigid and, as noted above, includes a pre-formed, curved section.

[0023] The shaft assembly (200) further includes a trocar actuation rod (220) and a trocar actuation band assembly (230). The distal end of the trocar actuation band assembly (230) is fixedly secured to the proximal end of the trocar shaft (332). The proximal end of the trocar actuation band assembly (230) is fixedly secured to the distal end of the trocar actuation rod (220). It should be understood, therefore, that the trocar (330) translates longitudinally relative to the outer sheath (210) in response to translation of the trocar actuation band assembly (230) and trocar actuation rod (220) relative to the outer sheath (210). The trocar actuation band assembly (230) is configured to bend so that as the trocar actuation band assembly (230) is translated longitudinally relative to the outer sheath (210), the trocar actuation band assembly (230) can move along a preformed curve in the shaft assembly (200). However, the trocar actuation band assembly (230) has sufficient column and tensile strength to transfer distal and proximal forces from the trocar actuation rod (220) to the trocar shaft (332). The trocar actuation rod (220) is rigid. The clip (222) is fixedly secured to the trocar actuation rod (220) and is configured to cooperate with complementary features in the handle assembly (100) to prevent the trocar actuation rod (220) from rotating within the handle assembly (100) while allowing the trocar actuation rod (220) to translate longitudinally within the handle assembly (100). The trocar actuation rod (220) further includes a coarse helical thread (224) and a fine helical thread (226).

[0024] The shaft assembly (200) further includes a stapling head assembly driver (240) that is slidably received within the outer sheath (210). The distal end of the stapling head assembly driver (240) is fixedly secured to the proximal end of the staple driver member (350). The proximal end of the stapling head assembly driver (240) is secured to the drive bracket (250) via a pin (242). It should be understood, therefore, that the staple driver member (350) translates longitudinally relative to the outer sheath (210) in response to translation of the stapling head assembly driver (240) and drive bracket (250) relative to the outer sheath (210). The stapling head assembly driver (240) is configured with a bend that allows the stapling head assembly driver (240) to move along a preformed curve in the shaft assembly (200) as the stapling head assembly driver (240) translates longitudinally relative to the outer sheath (210). However, the stapling head assembly driver (240) has sufficient column strength to transfer distal forces from the drive bracket (250) to the staple driver member (350).

[0025] D. Exemplary Handle Assembly and User Input Mechanism 1, handle assembly (100) includes a casing (110) having a lower portion defining an angled pistol grip (112) and an upper portion supporting a user interface mechanism (114) and receiving a battery pack (120), as shown in further detail below. Handle assembly (100) further includes several mechanisms operable to actuate anvil (400) and stapling head assembly (300). Specifically, handle assembly (100) includes a rotatable knob (130), a safety trigger (140), a firing trigger (150), a motor (160), and a motor activation module (180). The knob 130 is coupled to the trocar actuation rod 220 via a nut (not shown), with the coarse helical threads 224 selectively engaging with a threaded engagement mechanism inside the nut and the fine helical threads 226 selectively engaging with a threaded engagement mechanism inside the knob 130. These complementary structures are configured to cause the trocar actuation rod 220 to initially translate proximally at a relatively slow rate, and then translate proximally at a relatively fast rate in response to rotation of the knob 130.

[0026] It should be understood that when the anvil (400) is coupled to the trocar (330), rotation of the knob (130) causes a corresponding translation of the anvil (400) relative to the stapling head assembly (300). It should also be understood that the knob (130) can be rotated in a first angular direction (e.g., clockwise) to retract the anvil (400) toward the stapling head assembly (300) and rotated in a second angular direction (e.g., counterclockwise) to advance the anvil (400) away from the stapling head assembly (300). Thus, the knob (130) can be used to adjust the gap distance (d) between the opposing surfaces (412, 322) of the anvil (400) and the stapling head assembly (300) until a suitable gap distance (d) is achieved, as shown, for example, in FIG. 7C described below.

[0027] The firing trigger (150) is operable to actuate the stapling head assembly (300) by activating the motor (160). The safety trigger (140) is operable to selectively block actuation of the firing trigger (150) based on the longitudinal position of the anvil (400) relative to the stapling head assembly (300). The handle assembly (100) also includes a component operable to selectively lock out both of the triggers (140, 150) based on the position of the anvil (400) relative to the stapling head assembly (300). For example, the safety trigger (140) may be prevented from rotating from an engaged position to a disengaged position until the position of the anvil (400) relative to the stapling head assembly (300) falls within a predefined range. Thus, actuation of the firing trigger (150) is blocked by the safety trigger (140), thereby preventing firing of the stapling head assembly (300), until the anvil position falls within the predefined range.

[0028] The firing trigger 150 of this example includes an integral actuation paddle (not shown), which may be similar to the paddle disclosed in U.S. Patent Application Publication No. 2017 / 0258471, which is incorporated herein by reference. The paddle is configured to activate a switch in a motor activation module 180 ( FIG. 1 ) when the firing trigger 150 pivots to a post-fire position. The motor activation module 180 is in communication with the battery pack 120 and the motor 160, such that the motor activation module 180 is configured to activate the motor 160 with power from the battery pack 120 in response to the paddle's activation of the switch in the motor activation module 180. In this manner, the motor 160 is activated when the firing trigger 150 pivots. As will be described in more detail below, activation of the motor 160 activates the stapling head assembly 300 via the drive bracket 250. Although not shown, and by way of example only, motor (160) may be operably coupled to drive bracket (250) via a gearbox coupled to an output shaft of motor (160), a rotary cam member coupled to the output shaft of the gearbox, and a cam follower coupled to the rotary cam member, for example, as disclosed in U.S. Patent Application Publication No. 2017 / 0258471, which is incorporated by reference above.

[0029] As best shown in Figures 1-2, the handle assembly 100 is further configured to releasably receive a battery pack 120 operable to power the motor 160, as described above. It should be understood that the battery pack 120 and the handle assembly 100 may have complementary electrical contacts, pins, and sockets and / or other features that provide an electrical communication path from the battery pack 120 to the electrically powered components within the handle assembly 100 when the battery pack 120 is coupled with the handle assembly 100. It should also be understood that in some variations, the battery pack 120 may be integrally integrated within the handle assembly 100 such that the battery pack 120 cannot be removed from the handle assembly 100.

[0030] E. Exemplary Anastomosis Procedure Using a Circular Stapling Instrument Figures 7A-7E illustrate an instrument 10 being used to create an anastomosis 70 between two tubular anatomical structures 20, 40. By way of example only, the tubular anatomical structures 20, 40 may include a section of the patient's esophagus, a section of the patient's colon, another section of the patient's digestive tract, or any other tubular anatomical structure. In some variations, one or more diseased portions of the patient's colon are removed, and the tubular anatomical structures 20, 40 in Figures 7A-7E illustrate the remaining resected portions of the colon.

[0031] As shown in FIG. 7A, the anvil (400) is positioned within one tubular anatomical structure (20), and the stapling head assembly (300) is positioned within the other tubular anatomical structure (40). In variations in which the tubular anatomical structures (20, 40) comprise sections of the patient's colon, the stapling head assembly (300) may be inserted through the patient's rectum. It should also be understood that while the procedure depicted in FIGS. 7A-7E is an open procedure, the procedure may also be performed laparoscopically. Various suitable methods by which the instrument (10) may be used to laparoscopically form an anastomosis (70) will be apparent to those skilled in the art in view of the teachings herein.

[0032] As shown in FIG. 7A , the anvil (400) is positioned within the tubular anatomical structure (20) so that the shank (420) protrudes from the open cutting end (22) of the tubular anatomical structure (20). In this embodiment, a purse string suture (30) is provided around the central region of the shank (420) to roughly secure the position of the anvil (400) within the tubular anatomical structure (20). In some other variations, the purse string suture (30) is fastened around the proximal end of the shank (420). In some such variations, the proximal end of the shank (420) may include a notch or other feature for securely capturing the purse string suture (30). Continuing with this embodiment, the stapling head assembly (300) is positioned within the tubular anatomical structure (40) so that the trocar (330) protrudes from the open cutting end (42) of the tubular anatomical structure (20). A purse string suture (50) is provided around the central region of the shaft (332) to roughly secure the position of the stapling head assembly (300) within the tubular anatomical structure (40). The stapling head assembly (300) is then urged distally to ensure that the stapling head assembly (300) is fully seated in the distal end of the tubular anatomical structure (40).

[0033] Next, as shown in FIG. 7B, the anvil 400 is secured to the trocar 330 by inserting the trocar 330 into the hole 422. The latch member 430 engages the head 334 of the trocar 330, thereby providing a secure fit between the anvil 400 and the trocar 330. The operator then rotates the knob 130 via the pistol grip 112 while holding the casing 110 stationary. This rotation of the knob 130 causes the trocar 330 and anvil 400 to retract proximally. As shown in FIG. 7C, this proximal retraction of the trocar 330 and anvil 400 compresses the tissue of the tubular anatomical structure 20, 40 between the surfaces 412, 322 of the anvil 400 and the stapling head assembly 300. When this occurs, the operator can observe tactile resistance or feedback through knob 130 while turning knob 130, which indicates that the tissue is being compressed. As the tissue is compressed, the operator can visually observe the position of indicator needle 522 within user interface mechanism 114 of handle assembly 100 to determine if the gap distance d between opposing surfaces 412, 322 of anvil 400 and stapling head assembly 300 is adequate, and, if adjustment is necessary, make the necessary adjustment via knob 130.

[0034] After the operator properly sets the gap distance (d) via knob (130), the operator pivots safety trigger (140) toward pistol grip (112) to enable actuation of firing trigger (150). The operator then pivots firing trigger (150) toward pistol grip (112), thus causing paddle (158) to activate a switch in motor activation module (180), thereby activating and rotating motor (160). Such rotation of motor (160) causes actuation (or "firing") of stapling head assembly (300) by distally actuating drive bracket (250), thereby driving knife member (340) and staple driver member (350) distally, as shown in FIG. 7D. As knife member (340) translates distally, cutting edge (342) of knife member (340) cuts excess tissue located within annular recess (418) of anvil (400) and within knife member (340).

[0035] As shown in FIG. 3 , the anvil (400) of this embodiment includes a breakaway washer (417) positioned within an annular recess (418). This washer (417) is broken by the knife member (340) when the knife member (340) moves through its full distal range of motion, from the position illustrated in FIG. 7C to the position illustrated in FIG. 7D . The mechanism of the stapler (10) may be configured to provide increasing mechanical advantage as the knife member (340) reaches the end of its distal motion, thereby providing the greater force necessary to break the washer (417). Of course, in some variations, the breakaway washer (417) may be omitted entirely. It should be understood that in variations in which a washer (417) is included, the washer (417) may also serve as a cutting board for the knife member (340) to assist in cutting tissue.

[0036] As the staple driver member (350) translates distally from the position shown in Figure 7C to the position shown in Figure 7D, the staple driver member (350) drives the staples (90) through the tissue of the tubular anatomical structures (20, 40) and into the staple forming pockets (414) of the anvil (400). The staple forming pockets (414) deform the driven staples (90), for example, into a "B" shape or a three-dimensional shape such that the formed staples (90) secure the ends of the tissue together, thereby joining the tubular anatomical structure (20) with the tubular anatomical structure (40).

[0037] As shown in FIG. 7D, after the operator actuates the stapling head assembly (300), the operator rotates the knob (130) to drive the anvil (400) distally away from the stapling head assembly (300), increasing the gap distance (d) and facilitating the release of tissue between the surfaces (412, 322). The operator then removes the instrument (10) from the patient while the anvil (400) is still secured to the trocar (330). Referring again to the example in which the tubular anatomical structures (20, 40) comprise a section of the patient's colon, the instrument (10) may be removed through the patient's rectum. Once the instrument (10) is removed, the tubular anatomical structures (20, 40) are left secured together by the two annular rows of staples (90) at the anastomosis (70), as shown in FIG. 7E. The inner diameter of the anastomosis (70) is defined by the cut edge (60) left by the knife member (340).

[0038] F. Exemplary User Interface Features of the Handle Assembly As best shown in Figure 8, handle assembly (100) of surgical stapling instrument (10) further includes a user interface mechanism (114) configured to provide visual feedback to the operator indicating the positioning of anvil (400) relative to stapling head assembly (300) during a surgical procedure. Thus, the operator can verify that the proper gap distance (d) between the anvil (400) and stapling assembly (300) has been achieved by viewing user interface mechanism (114) while rotating knob (130).

[0039] The user interface mechanism 114 of this embodiment includes a graphical indicator 500, including markings 502, 504, 506, graphical representations of staples 510, 512, and a checkmark graphic 514. The user interface mechanism 114 further defines a window 520 through which an indicator needle 522 may be viewed. In some variations, the user interface mechanism 114 further includes a field 530 that may indicate a diameter associated with the size of the stapling head assembly 300, the size of the staples in the stapling head assembly 300, the size of the gap defined between the anvil 400 and the stapling head assembly 300, and / or other information. By way of example only, the field 530 may indicate a stapling head assembly 300 size of 23 mm, 25 mm, 29 mm, or 31 mm.

[0040] As the operator rotates the knob 130 to adjust the longitudinal position of the anvil 400 relative to the stapling head assembly 300, the operator can observe the position of the indicator needle 522 through the window 520. Initially, the indicator needle 522 may be positioned at or near the distal end of the window 520. As the anvil 400 continues to move proximally, the indicator needle 522 eventually moves proximally relative to the window 520. The operator can view the position of the indicator needle 522 in relation to the fixed line markings 502, 504, 506. The distal-most and proximal-most markings 502, 506 may represent the boundaries of a "green zone," which is the range of acceptable distances between the anvil 400 and the stapling head assembly 300 for successful actuation of the stapling head assembly 300. Thus, when indicator needle (522) is distal to the distal-most marking (502), the distance between the anvil (400) and the stapling head assembly (300) is too great, and when indicator needle (522) is proximal to the proximal-most marking (506), the distance between the anvil (400) and the stapling head assembly (300) is too small. Marking (504) is positioned longitudinally between markings (502) and (506). Graphical representation (510) represents a relatively tall formed staple (e.g., suitable for use with relatively thick tissue), while graphical representation (512) represents a relatively short formed staple (e.g., suitable for use with relatively thin tissue). Thus, the graphical representations (510, 512) can facilitate an operator's decision-making regarding whether and how to obtain a desired formed staple height by selecting the appropriate corresponding spatial relationship between the indicator needle (522) and the markings (502, 504, 506) based on tissue observation or otherwise.

[0041] In this embodiment, window 520 is illuminated by a light emitting diode (LED) (not shown) to further facilitate visualization of indicator needle 522 within window 520. Additionally, checkmark graphic 514 is illuminated by another LED (not shown) once stapling head assembly 300 has completed a stapling and severing cycle. Thus, the operator can further rely on the illumination of checkmark graphic 514 to confirm that the stapling and severing cycle has been completed and thereby confirm that it is safe to advance anvil 400 distally away from anastomosis 70 to release the tissue and thereafter remove instrument 10 from the patient.

[0042] The circular surgical stapling instrument (10) may further be configured and operative in accordance with at least some of the teachings of U.S. Patent Application Publication No. 2017 / 0258471, which is incorporated by reference above.

[0043] II. Exemplary Circular Surgical Stapling Instrument with Independent Control of Closing, Stapling, and Cutting In some cases, it may be desirable to provide variations of circular surgical stapling instruments (10) that exhibit powered actuation of the anvil (400) in addition to powered actuation of the internal firing components of the stapling head assembly (300). Furthermore, it may be desirable to provide variations of such instruments (10) with multiple actuators that allow for independent powered actuation of the anvil (400), staple driver member (350), and knife member (340) so that the resulting closure, stapling, and cutting strokes performed by such instruments can be controlled independently of one another in response to user input.

[0044] Although the following teachings are disclosed in the context of a circular surgical stapler, it will be understood that such teachings may also be applied to other types of surgical staplers. By way of example only, such other staplers may include right-angle surgical staplers of the type disclosed in U.S. Patent No. 10,045,780, entitled "Application of Staples in Lower Anternal Bowel Rescence," issued August 14, 2018, the disclosure of which is incorporated herein by reference.

[0045] A. Overview of a circular surgical stapling instrument having independently controlled actuators 9 illustrates an exemplary circular surgical stapling instrument (600) exhibiting the above-described types of construction and function. It will be understood that the instrument (600) is similar to the above-described instrument (10), except as otherwise described below. Like the instrument (10), the instrument (600) generally includes a body assembly in the form of a handle assembly (610), a shaft assembly (630) extending distally from the handle assembly (610), a stapling head assembly (640) disposed at the distal end of the shaft assembly (630), and an anvil (650) configured to releasably couple with an actuatable closure member in the form of a trocar (642) of the stapling head assembly (640). The anvil (650) is selectively retractable and extendable relative to the stapling head assembly by the trocar (642) to clamp tissue against a distally-facing deck surface (644) of the stapling head assembly (640). The stapling head assembly (640) is selectively operable to eject staples distally relative to the anvil (650) into the clamped tissue and to cut the clamped tissue with a cylindrical knife member (not shown) similar to the knife member (340) described above. Thus, the stapling head assembly (640) and the anvil (650) cooperate to define an end effector stapling assembly operable to clamp, staple, and cut tissue in response to user input.

[0046] The handle assembly 610 includes a casing 612 defining a pistol grip 614, a user interface 616 disposed on an upper side of the casing 612 adjacent the distal end thereof, and a knob 618 rotatably disposed on the proximal end thereof. The user interface 616 and knob 618 are similar to the user interface 114 and knob 130 described above, except as otherwise described below. The casing 612 of this example includes an open-end proximal cavity (not shown) configured to releasably receive and retain a battery pack 620 similar to the battery pack 120 and operable to power a motor unit 660 (see FIG. 10 ) housed within the casing 612.

[0047] The handle assembly 610 of this embodiment further includes a safety member 622, a closure trigger 624, and a firing trigger 626, each of which is independently movable relative to the pistol grip 614. Actuation of the closure trigger 624 is configured to activate a motor unit 660 to initiate actuation of a trocar actuator 662 (see FIG. 10), thereby effecting closure of the anvil 650 against the stapling head assembly 640 to clamp tissue therebetween. Actuation of the firing trigger 626 is configured to activate the motor unit 660 to initiate actuation of a staple actuator 664 and a knife actuator 666 (see FIG. 10), thereby stapling and severing the clamped tissue. As will be described in more detail below in connection with Figure 11, the instrument (600) is configured to independently control the actuation of the staple actuator (664) and the knife actuator (666) in response to a single actuation of the firing trigger (626). In this manner, precise timing of the initiation of the cutting stroke relative to the initiation of the stapling stroke can be achieved.

[0048] The safety member 622 in this example is in the form of a protrusion, such as a pivotable trigger similar to the safety trigger 140, configured to directly or indirectly engage with and selectively prevent actuation of the closure trigger 624 and / or the firing trigger 626. For example, the safety member 622 may be configured to prevent actuation of the closure trigger 624 until the instrument 600 detects that the anvil 650 is fully attached to the trocar 642. Additionally or alternatively, the safety member 622 may be configured to prevent actuation of the firing trigger 626 until the anvil 650 is disposed in a predetermined longitudinal position relative to the stapling head assembly 640, defining a particular gap distance (d) therebetween (see FIG. 7C ).

[0049] The actuators (662, 664, 666) of the instrument (600), shown schematically in FIG. 10, are configured to operably couple corresponding actuatable components of the instrument (600) to the motor unit (660). In particular, the trocar actuator (662) operably couples the trocar (642) of the stapling head assembly (640) to the motor unit (660). Thus, the trocar actuator (662) is configured to actuate the trocar (642), and thereby the anvil (650), proximally and distally in response to actuation of the motor unit (660) when the motor unit (660) is operably engaged with the trocar actuator (662). The trocar actuator (662) may include an elongated member, similar to the trocar actuation rod (220) combined with the trocar actuation band assembly (230) of the instrument (10), that is translatably disposed within the shaft assembly (630).

[0050] The staple actuator (664) operably couples a staple driver member (not shown) of the stapling head assembly (640) to the motor unit (660) independent of the trocar actuator (662). Thus, the staple actuator (664) is configured to distally actuate the staple driver member, and thereby the staples (not shown) housed within the stapling head assembly (640), in response to actuation of the motor unit (660) when the motor unit (660) is operably engaged with the staple actuator (664). The staple actuator (664) may include an elongated member similar to the stapling head assembly driver (240) of the instrument (10), the member being translatably disposed within the shaft assembly (630) independent of the trocar actuator (662).

[0051] The knife actuator (666) operably couples a cylindrical knife member (not shown) of the stapling head assembly (640) to the motor unit (660) independently of the trocar actuator (662) and the staple actuator (664). Thus, the knife actuator (666) is configured to longitudinally actuate the knife member in response to actuation of the motor unit (660) when the motor unit (660) is operably engaged with the knife actuator (666). The knife actuator (666) may include an elongated member similar to the stapling head assembly driver (240) of the instrument (10), which is translatably disposed within the shaft assembly (630) independently of the trocar actuator (662) and the staple actuator (664). In this manner, the actuators (662, 664, 666) are configured to cooperate with the motor unit (660) to independently actuate tissue clamping, tissue stapling, and tissue cutting.

[0052] The knob 618 of the handle assembly 610 of this embodiment is operably coupled to the trocar actuator 662, such that the knob 618 is operable as an anvil closure emergency release mechanism. In that regard, the trocar actuator 662 is primarily driven by the motor unit 660, but is longitudinally translatable in response to rotation of the knob 618, for example, when the motor unit 660 is stopped or otherwise disengaged from the trocar actuator 662. Thus, the knob 618 can be rotated following partial or full proximal retraction of the anvil 650 toward the stapling head assembly 640, thereby extending the anvil 650 distally away from the stapling head assembly 640, for example, to release tissue captured therebetween. In such variations, knob (618) may be coupled to trocar actuator (662) via a mechanism similar to that described above in connection with knob (130) of instrument (10), including, for example, threaded portions (224, 226) of trocar actuation rod (220). However, it will be understood that in some variations, such as when trocar actuator (662) is driven solely by motor unit (660), knob (618) may be omitted from instrument (600).

[0053] The instrument (600) may be modified in accordance with U.S. Patent No. 9,445,816, issued September 20, 2016, entitled "Circular Stapler with Selectable Motorized and Manual Control," U.S. Patent No. 9,532,783, issued January 3, 2017, entitled "Circular Stapler with Selectable Motorized and Manual Control, Including a Control Ring," U.S. Patent No. 9,597,081, issued March 21, 2017, entitled "Motor Driven Rotary Input Circular Stapler with Modular End Effector," and U.S. Patent No. 9,463,022, issued October 11, 2016, entitled "Motor Driven Rotary Input Circular Stapler with Lockable Flexible End Effector," the disclosures of which are incorporated herein by reference. The present invention may be further configured and operable in accordance with at least some of the teachings of U.S. Patent Application Publication No. 2018 / 0368836, published December 27, 2018, entitled "Surgical Stapler with Independently Actuated Drivers to Provide Varying Staple Heights," and / or any of the other patent documents identified herein.

[0054] B. Exemplary Control System for a Circular Surgical Stapling Instrument As shown schematically in Figure 10, the instrument 600 further includes a control system 670 operable to control the actuation of the trocar actuator 662, staple actuator 664, and knife actuator 666 of the instrument 600. The control system 670 includes a control module 672, a motor unit 660, a user interface 616, and a sensor 674, suitably configured and arranged such that the control module 672 is in communication with each of the motor unit 660, the user interface 616, and the sensor 674. The control module 672 includes a processor and is operable to store pre-programmed instrument control algorithms and to receive input from the user interface 616 and the sensor 674. Based on these stored control algorithms and received inputs, the control module (672) is configured to control the motor unit (660) using pulse width modulation (PWM) to drive the operation of the trocar actuator (662), staple actuator (664), and knife actuator (666) independently of one another to clamp, staple, and cut tissue.

[0055] The motor unit (660) includes one or more motors and is operably coupled to the trocar actuator (662), the staple actuator (664), and the knife actuator (666). In some variations, the motor unit (660) may comprise a single motor operably coupled to and configured to drive all three actuators (662, 664, 666). In such variations, the motor unit (660) may be coupled to the actuators (662, 664, 666) via one or more power transmission assemblies (not shown), such as gear assemblies, various suitable types of which will be apparent to those skilled in the art in view of the teachings herein and the incorporated references. In other variations, the motor unit (660) may comprise three motors, each dedicated to driving a corresponding one of the actuators (662, 664, 666). In a further variation, the motor unit (660) may include two motors, a first motor configured to drive the trocar actuator (662) and a second motor configured with the aid of a power transmission assembly to drive the staple actuator (664) and the knife actuator (666). It will be appreciated that the motor unit (660) may include various other quantities and configurations of motors in other variations.

[0056] The sensor (674) is disposed within or otherwise coupled to the stapling head assembly (640), shaft assembly (630), or handle assembly (610) and is operable to monitor one or more conditions of the instrument (600) during use. For example, the sensor (674) may be configured to monitor the translation of any one or more of the actuators (662, 664, 666) and / or their adjacent components, such as the trocar (642). In some such variations, the sensor (674) may be mounted directly to the actuators (662, 664, 666) or any one of their adjacent components. In other such variations, the sensor (674) may be fixedly mounted within the stapling head assembly (640), shaft assembly (630), or handle assembly (610) such that the actuators (662, 664, 666) and their adjacent components move relative to the sensor (674).

[0057] In some variations, sensor 674 may be configured to detect secure attachment of anvil 650 to trocar 642, as disclosed, for example, in U.S. Patent No. 10,307,157, incorporated by reference above, or in even filed U.S. patent application Ser. No. [Attorney Docket No. END9142USNP1], entitled "Anvil Retention and Release Features for Powered Circular Surgical Stapler," the disclosure of which is incorporated by reference herein. In other variations, sensor 674 may be configured to detect some feature of the particular stapling head assembly 640 coupled to shaft assembly 630, such as the diameter of the stapling head assembly 640 or the size of the staples (not shown) housed therein. In some such variations, the sensor (674) may be configured to detect such features of the stapling head assembly (640) via radio frequency identification (RFID) of electronic information stored in a tag element disposed on or within the stapling head assembly (640), as disclosed, for example, in U.S. Provisional Patent Application No. 62 / 868,457, filed June 28, 2019, entitled "Surgical Systems with Multiple RFID Tags," the disclosure of which is incorporated herein by reference.

[0058] In yet other variations, the sensor 674 may be in direct communication with the motor unit 660. For example, the sensor 674 may include a current sensor operable to monitor the current drawn by the motor unit 660 or an encoder operable to monitor the rotational output of the motor unit 660. Furthermore, while only one sensor 674 is shown in the diagram of FIG. 10, it will be understood that the sensor 674 may include multiple sensors, each individual sensor 674 configured to monitor and communicate with the control module 672 regarding one or more respective conditions of the instrument 600. It will be further understood that the sensor 674 may be in the form of a sensor assembly including a variety of suitable types of sensors that will be readily apparent to those skilled in the art in light of the teachings herein and beyond.

[0059] User interface (616) is similar to user interface (114) described above, except that user interface (616) is further configured to receive user input and communicate the user input to control module (672). In that regard, user interface (616) may include one or more buttons, dials, other actuatable elements, or display graphics selectable by a user to indicate specific information regarding the surgical procedure being performed or the stapling head assembly (640). By way of example only, such information may include any of the following: a desired staple forming height, the anvil (650) should be actuated at during closure, the corresponding gap between the anvil (650) and the stapling head assembly (640), the type or nominal thickness of tissue fired by instrument (600), and / or the diameter of the stapling head assembly (640). As described in further detail below, for example, such information, in combination with information provided by sensors (674), can be used by control module (672) to adjust the stroke and / or actuation speed of actuators (662, 664, 666) and / or to adjust timing pauses between powered actuations of actuators (662, 664, 666) to ensure optimal clamping, stapling, and cutting of tissue during the procedure.

[0060] C. Exemplary Methods for Controlling a Circular Surgical Stapler Figure 11 illustrates an exemplary method (700) for controlling the circular surgical stapling instrument (600) via the control system (670) shown in Figure 10. In step (702), the instrument (600) is powered on in response to being energized by the battery pack (620), for example, when the battery pack (620) is fully inserted into the proximal end of the handle assembly (610) after the instrument (600) is removed from its product packaging. Upon removal from the packaging, the anvil (650) is already secured to the trocar (642) and in a fully open position, and the staple retainer (646) (see Figure 14) is secured to the deck surface (644).

[0061] In this embodiment, after the instrument 600 is powered on, the control module 672 enters an anvil stroke calibration mode at step 704, which may occur automatically or in response to user input provided, for example, via the user interface 616. In this calibration mode, the control module 672 activates the motor unit 660 to drive the trocar actuator 662 to proximally retract the trocar 642, thereby closing the anvil 650 against the staple retainer 646, or alternatively, against the deck surface 644 if the staple retainer 646 is removed. The control module 672 may detect that the anvil 650 has reached the closed position by detecting, via the sensor 674, an increase in the current load on the motor unit 660 when the anvil 650 contacts the staple retainer 646 or the deck surface 644. The control module 672 monitors the stroke (i.e., longitudinal displacement) of the anvil 650 during this retraction process and compares it to the expected stroke of the anvil 650. Based on this comparison and any discrepancies noted between the two stroke values, the control module 672 then calibrates the actuation algorithm executed to activate the motor unit 660 and actuate the trocar actuator 662 during the surgical procedure, thereby ensuring accurate actuation of the anvil 650 thereafter. Additionally or alternatively, anvil stroke calibration can be performed by the control module 672 in real time during the surgical procedure as the anvil 650 is being retracted to clamp tissue. Such anvil stroke calibration is described in further detail below. It will be appreciated that the stroke of one or more other actuatable members of instrument (600) may be calibrated in a similar manner prior to or during a surgical procedure, and that calibration of the anvil closing stroke may be applied by control module (672) to similarly calibrate the stapling and / or cutting strokes of instrument (600).

[0062] In step 706, control module 672 determines the diameter of stapling head assembly 640. As described above, stapling head assembly 640 may be releasably attached to shaft assembly 630, such that stapling head assemblies 640 of various diameters can be interchangeably coupled to the distal end of shaft assembly 630 depending on the lumen size of the tissue structure to be treated by instrument 600. Control module 672 is configured to make this sizing determination based on user input provided via user interface 616 and / or information provided by sensor 674, for example, when sensor 674 is configured to sense the size of stapling head assembly 640 in the manner described above.

[0063] In step (708), control module (672) receives input from user interface (616) indicating a desired height of staples to be formed in tissue, selected by an operator via user interface (616). To achieve the selected staple height, control module (672) treats this staple height as equal to a corresponding gap distance (d) (see FIG. 7C ) established between anvil (650) and deck surface (644) of stapling head assembly (640) when anvil (650) is in a closed position.

[0064] Although steps (704, 706, 708) are shown in FIG. 11 as being performed in a particular order, it will be understood that these steps (704, 706, 708) may be performed in various orders relative to one another after powering on instrument (600) in step (702) and before actuation of staple actuator (664), as described below.

[0065] After completing steps (704, 706, 708), the operator removes the anvil (650) from the trocar (642) and subsequently positions the anvil (650) within a first tubular tissue structure of the patient and, separately, positions the stapling head assembly (640) within a second tubular structure of the patient. The operator then attaches the anvil (650) to the trocar (642) within the patient, for example, as shown in Figures 7A-7B above, at which point the control module (672) detects that attachment has occurred in step (710). Such detection may be performed by a sensor (674) that communicates a corresponding signal to the control module (672).

[0066] In step 712, the control module 672 detects that the closure trigger 624 has been actuated by the operator. The control module 672 then proceeds to step 714 and directs the motor unit 660 to drive the trocar actuator 662 to actuate the trocar 642 proximally, thereby retracting the anvil 650 to a closed position where the selected staple height and corresponding gap distance (d) is achieved. In some variations, the control module 672 may be configured to initiate retraction of the trocar 642 and anvil 650 only in response to actuation of the closure trigger 624 occurring after attachment of the anvil 650 to the trocar 642 is detected in step 710. The operator may monitor the retraction of the anvil 650 toward its closed position via visual indicia and / or display graphics on the user interface 616.

[0067] Additionally, in some variations, the control module (672) may control the motor unit (660) to retract the anvil (650) proximally through the anvil closing stroke in two consecutive stages. For example, the control module (672) may instruct the motor unit (660) to retract the anvil (650) through a first portion of the anvil closing stroke, at which point the control module (672) pauses activation of the motor unit (660) for a predetermined period of time (e.g., several seconds). At the end of this waiting period, the control module (672) reactivates the motor unit (660) to continue retracting the anvil (650) through the remainder of the anvil closing stroke to its closed position. Including such a pause in the retraction of the anvil (650) may allow tissue compressed between the anvil (650) and the deck surface (644) to at least partially settle (or "creep"). Advantageously, this tissue settling results in a reduction in the axial tension load on the trocar (642) and the resulting current load on the motor unit (660) as the anvil (650) advances proximally to a fully closed position defined by the target staple height input provided by the user in step (708).

[0068] In step 716, the control module 672 detects that the firing trigger 626 has been actuated by the operator after the anvil closing stroke has been completed. In this embodiment, in response to detecting this actuation, the control module 672 monitors the completion of a predetermined period of time, measured from the completion of the anvil closing stroke, during which the staple actuator 664 and the knife actuator 666 remain stationary. This waiting period after anvil closure allows the clamped tissue to settle (or "spread") to a fully compressed state before the stapling head assembly 640 is fired, thereby reducing the axial load on the staple actuator 664 and the knife actuator 666 and the resulting current load on the motor unit 660 during each stapling and severing sequence. It will be understood that this waiting period may be omitted in some variations.

[0069] Upon completion of the wait period indicated by step 718, control module 672 initiates distal actuation of staple driver member (not shown) in step 720 to begin stapling the clamped tissue. In particular, control module 672 activates motor unit 660 to activate and drive staple actuator 664 to actuate the staple driver member distally through stapling head assembly 640, thereby driving staples into tissue against anvil 650, for example, in a manner similar to that shown in FIG. 7D. Having initiated actuation of staple actuator 664, control module 672 observes another predetermined period during which motor unit 660 continues to drive staple actuator 664 through a stapling stroke in step 722. Concurrently, in step (724), control module (672) communicates with sensor (674) to detect when the staple driver member reaches a predetermined longitudinal position within stapling head assembly (640). Such position may correspond to the point at which an individual staple driver (not shown), similar to staple driver (352) described above, reaches deck surface (644), thereby causing a staple to be at least partially formed within the clamped tissue. This process is described in further detail below in connection with Figures 17-19.

[0070] In response to detecting the completion of the predetermined period of time in step (722) and / or detecting that the staple driver member has reached a predetermined longitudinal position in step (724), control module (672) then initiates distal actuation of a knife member (not shown) to begin severing tissue in step (726). In particular, control module (672) activates motor unit (660) to operate and drive knife actuator (666) to actuate the knife member distally through stapling head assembly (640), thereby severing tissue, for example, in a manner similar to that shown in FIG. 7D.

[0071] As noted above, delaying the initiation of the cutting stroke relative to the initiation of the stapling stroke, enabled by the independent actuation of the staple and knife actuators (662, 664, 666), ensures that the staples are at least partially formed within the tissue before tissue cutting begins. Advantageously, this approach allows the staples to be secured within the clamped tissue prior to cutting, thereby preventing lateral movement of the tissue and resulting mis-forming of the staples as the knife member is driven distally.

[0072] The end of the distal cutting stroke of the knife member may correspond to the point at which the knife member breaks a washer (not shown) in the anvil (650), similar to washer (417) described above. Upon completion of the distal cutting stroke, the control module (672) directs the motor unit (660) to retract the knife member proximally back into the stapling head assembly (640), in step (728). In some variations, distal extension and proximal retraction of the knife member may be achieved by energizing the motor unit (660) through a continuous and uniform range of motion, as disclosed, for example, in U.S. Patent Application Publication No. 2017 / 0258471, incorporated by reference above. In other variations, the control module (672) may be programmed to communicate with the sensor (674) to detect completion of the distal cutting stroke and thereafter specifically direct the motor unit (660) to drive the knife actuator (666) in an alternative manner to proximally retract the knife member. In any such variations, the sensor (674) may include an encoder configured to monitor the rotational output of the motor unit (660).

[0073] Concurrent with or subsequent to the knife retraction step (728), the control module (672) instructs the motor unit (660) to drive the trocar actuator (662) distally, in step (730), thereby extending the anvil (650) distally to a predetermined position against the deck surface (644) of the stapling head assembly (640). This distal extension allows the stapled tissue to be released from between the anvil (650) and the stapling head assembly (640), and the instrument (600) can be withdrawn from the patient with the anvil (650) still attached to the trocar (642).

[0074] III. Exemplary Methods for Calibrating the Actuation Stroke of a Circular Surgical Stapler As mentioned above, it may be desirable to calibrate the longitudinal actuation (or "stroke") of the trocar actuator (662), staple actuator (664), and knife actuator (666) prior to or during a surgical procedure to ensure that the actual longitudinal displacement of the anvil (650), staple driver member (not shown), and knife member (not shown) matches the corresponding expected longitudinal displacement expected by the control module (672) based on a given rotational output of the motor unit (660). As described below, proper calibration of these strokes enables the circular stapler (600) to accurately clamp, staple, and sever patient tissue.

[0075] The control module 672 of this embodiment is configured to store and execute a closure member actuation algorithm for longitudinally actuating the trocar actuator 662 (and thereby the trocar 642 and the anvil 650) to clamp tissue, a staple driver member actuation algorithm for longitudinally actuating the staple actuator 664 (and thereby the staple driver member) to staple tissue, and a knife member actuation algorithm for longitudinally actuating the knife actuator 666 (and thereby the knife member) to sever tissue. Each of these actuation algorithms stored by the control module 672 includes a correlation between a given rotational output of the motor unit 660 and the expected longitudinal displacement of a corresponding actuated member of the stapler 600 achieved by that particular rotational output. As described above, the rotational output of the motor unit 660 can be monitored by an encoder operably coupled to the motor unit 660 and in communication with the control module 672. As described below, the longitudinal stroke of the actuators (662, 664, 666) can be calibrated by adjusting corresponding actuation algorithms stored by the control module (672).

[0076] A. Exemplary Actuation Stroke Calibration Method FIG. 12 illustrates an exemplary method for calibrating the stroke of at least the trocar actuator 662 (and the connected trocar 642 and anvil 650) by adjusting the closure member actuation algorithm to redefine the correlation between the rotational output of the motor unit 660 and the longitudinal displacement of the trocar actuator 662. As described above in connection with step 704 of the method of operation 700 shown in FIG. 11, this calibration process may be performed when the circular stapler 600 is initially unpackaged prior to a surgical procedure. Additionally or alternatively, this calibration process may be performed in real time during a surgical procedure, as described in more detail below. Furthermore, as described below, adjustments to the closure member actuation algorithm may be used by the control module 672 to similarly adjust the staple driver member actuation algorithm and the knife member actuation algorithm, thereby calibrating the staple driver member stroke and the knife member stroke. However, in some variations, steps similar to those shown in FIG. 12 may be performed by the control module (672) to adjust the staple driver member actuation algorithm and the knife member actuation algorithm independently of the closure member actuation algorithm.

[0077] 12 , calibration method (800) begins with a start event in step (802), which may be the initial mating of the battery pack (620) with the handle assembly (610) after unpacking the device, or the actuation of the closure trigger (624) following attachment of the anvil (650) to the trocar (642) during a surgical procedure. In response to the start event (802), control module (672) executes a stored movable member actuation algorithm to activate motor unit (660) in step (804) to actuate trocar actuator (662) proximally and transition the anvil (650) to a closed state. Prior to or during execution of the closure member actuation algorithm, control module 672 determines in step 806, for example, by detection by sensor 674 in the form of a position sensor, that one of the monitored trocar actuator 662, trocar 642, or anvil 650 (each a "closure member" herein) is in a first predetermined position. By way of example only, the first predetermined position may be when anvil 650 is in a fully open position (X 0 ), as shown in FIG. 13A. O ), where in the fully open state, the anvil (650) is in its distal-most position relative to the deck surface (644). In another example, the first predetermined position may correspond to the anvil (650) being in a partially closed state. The motor unit (660) continues to retract the trocar actuator (662) proximally while the control module (672) monitors the actual longitudinal displacement of one of the monitored closure members (642, 650, 662) in step (808), for example, via a sensor (674). It will be appreciated that the trocar actuator (662), trocar (642), and anvil (650) in this example translate together so that their longitudinal displacements are the same for a given power output of the motor unit (660).

[0078] In step 810, control module 672 determines that monitored closure members 642, 650, 662 have reached a second predetermined position proximal to the first predetermined position. By way of example only, the second predetermined position may correspond to anvil 650 being in an initial closed state, such as the position (X 100) in FIG. 13B. C ), the anvil (650) faces the deck surface (644) but is not drawn against the deck surface (644). In other variations, the second predetermined position may correspond to the anvil (650) being in a fully closed and overloaded state, in which the anvil (650) is compressed against the deck surface (644) or another structure. For example, FIG. 13C illustrates the anvil (650) in an exemplary fully closed and overloaded state (X OL ), in which the anvil (650) is drawn against the deck surface (644). Figure 14 shows another exemplary fully closed and overloaded position (X OL ), in which the anvil (650) is drawn against the staple retainer (646) before the retainer (646 is removed from the stapling head assembly (640) after unpacking the circular stapler (600). In that regard, it will be understood that Figures 13A-14 illustrate exemplary positions of the anvil (650) in the absence of tissue, for example, prior to the performance of a surgical procedure on a patient. However, as noted above, the calibration method (800) may also be performed in real time during a surgical procedure while the anvil (650) is closed on the patient's tissue.

[0079] In any such variations in which the monitored second predetermined position of the closure member (642, 650, 662) corresponds to the anvil (650) being drawn against another structure (e.g., the deck surface (644), the staple retainer (646), or the patient's tissue), reaching the second predetermined position can be identified by the control module (672) based on observing an increase in load on the closure system components. This load can be sensed in the form of a longitudinal force exerted on the trocar actuator (662) (and thereby on the anvil (650) and trocar (642)) or an electrical current drawn by the motor unit (660) while actuating the trocar actuator (662). In that regard, it will be appreciated that closure of the anvil 650 against the structure induces longitudinal extensional forces in the anvil 650, trocar 642, and trocar actuator 662, which makes further proximal retraction of these closure components by the motor unit 660 more difficult, thus increasing the current load on the motor unit 660. This increase in closure load can be detected by one or more sensors in the form of current or force sensors in communication with the control module 672.

[0080] Upon determining that the monitored closure members (642, 650, 662) have reached the second predetermined position, the control module (672) proceeds to step (812) and compares the actual longitudinal displacement of the monitored closure members (642, 650, 662) observed by the control module (672) via one or more sensors (674) with the predicted longitudinal displacement stored by the control module (672). The control module (672) evaluates whether there is a difference between the observed actual longitudinal displacement and the stored predicted longitudinal displacement in step (814). If the two longitudinal displacement values ​​are equal to each other or within a predetermined tolerance of each other and therefore not significantly different, the control module (672) proceeds to step (816) and executes the original stored actual algorithm in response to user actuation of the closure trigger (624) and firing trigger (626), for example, as outlined above in the steps of method (700).

[0081] Alternatively, if control module 672 determines that a significant difference exists between the actual longitudinal displacement and the expected longitudinal displacement, control module 672 proceeds to step 818 and adjusts at least the closure member actuation algorithm based on the determined difference. More specifically, in this embodiment, control module 672 redefines a stored correlation between a given rotational output of motor unit 660 and the corresponding expected longitudinal displacement of monitored closure members 642, 650, 662. The newly defined correlation relates the observed actual longitudinal displacement of closure members 642, 650, 662 to the rotational output of motor unit 660 during the observed longitudinal displacement of closure members 642, 650, 662. The rotational output of this new correlation may be the same as or different from the rotational output of the original correlation.

[0082] In some variations, the staple member actuation algorithm and the knife member actuation algorithm may be adjusted in a similar manner based on the same difference values ​​determined by the control module 672 in conjunction with the actuation of the monitored movable members 642, 650, 662. It will be appreciated that calibration of all three actuation algorithms ensures accurate longitudinal actuation of the anvil 650, staple driver member, and knife member of the stapler 600. After adjusting the closure member actuation algorithm, and optionally further adjusting the staple driver member and knife member actuation algorithms, the control module 672 proceeds to step 820 to execute the adjusted actual algorithms, for example, in response to user actuation of the closure trigger 624 and firing trigger 626, as outlined above in the steps of method 700.

[0083] As noted above, it will be appreciated that the closure member calibration process (800) of Figure 12 may be performed prior to a surgical procedure so that the longitudinal stroke of the trocar actuator (662) (as well as the trocar (642) and anvil (650)) is properly calibrated before clamping tissue. Additionally or alternatively, the calibration process (800) may be performed one or more times during a surgical procedure on tissue to ensure that the longitudinal stroke of the trocar actuator (662), and optionally the longitudinal strokes of the staple actuator (664) and knife actuator (666), remain properly configured throughout use.

[0084] 15 shows a line graph 830 illustrating an exemplary calibration of the longitudinal stroke of the trocar actuator 662 (and thereby the trocar 642 and anvil 650) according to the method 800 described above. The x-axis of the graph 830 represents time, and the y-axis of the graph 830 represents the distal displacement (δ) of the trocar actuator 662 relative to its most proximal position (i.e., the distal displacement of the anvil 650 relative to the deck surface 644) as interpreted by the control module 672. The first horizontal portion 834 of the illustrated curve 832 indicates that the trocar actuator 662 is in a dully extended position at a displacement (δ1) prior to longitudinal stroke calibration. In this embodiment, the trocar actuator (662) remains in a fully extended position throughout the initial events, including the removal of the stapler (600) from the packaging, as indicated by the vertical dashed line (836), the attachment of the battery pack (620) to the handle assembly (610), as indicated by the vertical dashed line (838), and the attachment of the anvil (650) to the trocar (642), as indicated by the vertical dashed line (840).

[0085] A first descending portion (842) of curve (832) represents the initial proximal retraction of the trocar actuator (662) to transition the anvil (650) from a fully open position to a partially closed position at a first, rapid actuation rate. A second descending portion (844) of curve (832) represents the final proximal retraction of the trocar actuator (662) to transition the anvil (650) from a partially closed state to a fully closed state at a second, slower actuation rate. OL), motor unit (660) experiences a sudden increase in current load, as represented by vertical line (846). Control module (672) detects this increase in current load via sensor (674) and thereby determines that anvil (650) has reached a fully closed state. Control module (672) then proceeds to compare the actual observed longitudinal displacement of trocar actuator (662) observed during proximal retraction with the expected longitudinal displacement, and control module (672) determines the difference between the two values.

[0086] In this example, control module 672 adjusts the closure member actuation algorithm based on the determined difference, thereby re-zeroing the proximal endpoint of the longitudinal stroke of trocar actuator 662, e.g., via the steps described above in connection with method 800. Control module 672 then executes the adjusted closure member actuation algorithm to distally extend trocar actuator 662 to a fully extended state, thereby moving anvil 650 to a fully open state (X 1 ), as represented by ascending curve portion 848. O The longitudinal stroke is now calibrated to the appropriate "zero" point, so that the fully extended state of the trocar actuator (662) and the corresponding fully open state (X O ) is registered as a new, larger displacement (δ2) on the displacement scale applied by control module 672. As shown in graph 830, the original displacement value (δ1) and the fully extended state of trocar actuator 662 (i.e., fully opened state of anvil 650 (X 1 )) are calculated by control module 672. O The difference between the adjusted displacement value (δ2) correlated to the displacement of the trocar actuator (662) is equal to the amount of displacement that the "zero" point of the trocar actuator (662) is adjusted by the control module (672).

[0087] Executing the adjusted closure member actuation algorithm for subsequent actuation of the trocar actuator 662 will result in precise positioning of the anvil 650 relative to the deck surface 644, and therefore precise clamping of tissue per user input. As described above, the control module 672 can apply this calibration of the closure member actuation algorithm to similarly calibrate the staple member actuation algorithm and the knife member actuation algorithm, thus further providing precise stapling and severing of tissue.

[0088] B. Exemplary Actuation of the Stapling Head Assembly Per User-Specified Tissue Gap As described above, the user interface (616) of the circular surgical stapler (600) is configured to receive and communicate user input to the control module (672). As shown in FIG. 16 , the visual display (680) of the user interface (616) (which may in other variations be in the form of a window similar to window (520)) includes a distal line marking (682) and a proximal line marking (684). The line markings (682, 684) define the boundaries of an acceptable tissue gap (referred to as the "green zone") defined longitudinally between the anvil (650) and the deck surface (644) of the stapling head assembly (640) to allow for proper formation of staples fired into tissue. The distal line marking (682) is used to indicate a tissue gap that is large enough (δ 0.5 mm) between the anvil (650) and the deck surface (644), as shown in FIG. 17A . AT The anvil (650) is moved to a distal "high" closed position (A T ) between the anvil (650) and the deck surface (644), as shown in FIG. 17B. AT The anvil (650) is moved to a proximal "low" closed position (A L6 illustrates a narrow tissue gap setting provided at a fixed position (e.g., for thicker tissue) on the stapler 692. As indicated by symbols (686, 688) on user interface (616), a wide tissue gap setting results in the formation of staples (692) having a higher formed height (e.g., for thicker tissue), and a narrow tissue gap setting results in the formation of staples (692) having a lower formed height (e.g., for thinner tissue).

[0089] The user interface (616) includes one or more selectable input mechanisms that allow a user to specify a desired tissue tap setting for the anvil (650) in the closed position, which is then communicated by the user interface (616) to the control module (672). As described above in connection with step (714) of method (700), the control module (672) is configured to control the motor unit (660) to proximally retract the trocar actuator (662) until the anvil (650) achieves the target tissue gap setting specified via user input. This may be confirmed by the control module (672) via communication with a sensor (674) in the form of a position sensor that may be located within the stapling head assembly, for example. As described above in connection with Figures 12-15, the longitudinal stroke of the trocar actuator (662) may be calibrated before and / or during closure of the anvil (650) on the patient's tissue so that the actual tissue gap (δ) defined between the anvil (650) and the deck surface (644) is equal to the target tissue gap (δ) specified by the user via the user interface (616).

[0090] The target tissue gap (δ) input by the user via the user interface (616) may be referenced by the control module (672) in controlling other aspects of operation of the stapler (600) as well. For example, in addition to controlling the longitudinal displacement of the trocar actuator (662) during the anvil closing stroke, the control module (672) may also control the longitudinal displacement of the staple actuator (664) during the stapling stroke and the longitudinal displacement of the knife actuator (666) during the cutting stroke based on the user input of the tissue gap. Specifically, the control module (672) may adjust the longitudinal displacement of each actuator (662, 664, 666) to ensure that the actuators (662, 664, 666) are longitudinally actuated the appropriate amount to provide a full stapling stroke and a full cutting stroke without under-actuating or over-actuating the target tissue gap. In that regard, it will be appreciated that calibrating the longitudinal stroke of the staple actuator 664 and the knife actuator 666 may be desirable to ensure that the staple actuator 664 and the knife actuator 666 are actuated the appropriate amount during a surgical procedure. As discussed above, the corresponding staple member actuation algorithm and knife member actuation algorithm may be appropriately adjusted based on adjustments made to the closure member actuation algorithm via calibration method 800. Alternatively, the staple member actuation algorithm and knife member actuation algorithm may be adjusted independently of the closure member actuation algorithm, for example, via steps similar to those of method 800.

[0091] The user input of the target tissue gap may also be referenced by the control module 672 to control the actuation speed of one or more of the actuators 662, 664, 666. For example, the control module 672 may decrease the actuation speed of one or more of the actuators 662, 664, 666 for larger tissue gaps and increase the actuation speed of one or more of the actuators 662, 664, 666 for smaller tissue gaps. In that regard, it will be appreciated that larger tissue gaps are often selected to accommodate thicker tissue, which may induce higher current loads on the motor unit 660 during stapling and cutting. Reducing the actuation speed of the staple actuator 664 and the knife actuator 666 for thicker tissue may therefore help maintain the current load on the motor unit 660 below a desired threshold.

[0092] IV. Exemplary Methods of Controlling Knife Member Actuation Relative to Staple Driver Member Actuation As described above in connection with steps (720-726) of method (700), control module (672) is configured to control motor unit (660) to independently actuate staple actuator (664) and knife actuator (666), such that the knife member is actuated distally only when staples (692) driven by the staple driver member have been at least partially formed within tissue by anvil (650). More specifically, the control module (672) communicates with a sensor (674) to detect when the staple actuator (664), the staple driver member (not shown), or an individual staple driver (690) of the staple driver member (see FIG. 18) has reached a predetermined longitudinal position where the upper ends of the staple drivers (690) and the crowns (694) of the staples (692) are positioned on the deck surface (644) such that the staple legs (696) are partially deformed by the anvil (650), as shown and described below in connection with FIG. 19B.

[0093] 18 and 19A show exemplary staple drivers (690) of the staple driver member of the circular stapler (600) in a fully recessed position (DO) within respective staple openings (699) of the stapling head assembly (640). Although not shown, it will be understood that the staple driver member (not shown) of the stapling head assembly (640) includes a plurality of staple drivers (690) arranged in an annular configuration similar to the staple drivers (352) of the staple driver member (350) described above. Each staple driver (690) is slidably arranged within a respective staple opening (699) of the deck member (698) and has an upper end that supports the crown (694) of a respective staple (692). When the staple actuator (664) is driven distally by the motor unit (660) in response to activation by the control module (672), the staple driver (690) drives each staple (692) distally from the staple opening (699), as shown in Figures 19B and 19C. Figure 19B shows the staple driver (690) in a partially extended position (D1) in which the upper end of the staple driver (690) and the staple crown (694) are positioned at the upper end of the staple opening (699) coincident with the deck surface (644). In this position, the staple legs (696) are received by the staple forming pockets (652) of the anvil (650), such that the staple legs (696) are partially deformed within the tissue (not shown) clamped between the anvil (650) and the deck surface (644). Figure 19C shows the staple driver (690) in a fully extended position (D2) in which the staple legs (696) of the staples (692) are fully formed within the clamped tissue against the anvil (650). As shown in Figures 19B and 19C, the free ends of the formed staple legs (696) are bent proximally toward the staple crown (694).

[0094] The control module (672) of this variation is configured to initiate distal actuation of the knife actuator (666) (and thereby distal actuation of the knife member) upon determining that the staple driver (690) has reached the partially extended position (D2) shown in FIG. 19B. This determination by the control module (672) may be made via communication with one or more sensors configured to monitor the longitudinal position of one or more of the staple actuator (664), staple driver member, or staple driver (690). Furthermore, as described above, calibrating the longitudinal stroke of the trocar actuator (662) prior to actuating the staple actuator (664) ensures that the anvil (650) in the closed position defines an appropriate tissue gap (δ) relative to the deck surface (644) that corresponds to the target tissue gap specified via the user interface (616). This, in turn, ensures that distal actuation of the knife actuator (666) does not commence until the staple legs (696) have actually been at least partially deformed an expected amount based on the user-specified target tissue gap. This approach ensures that the clamped tissue is not destroyed by engagement by the knife member during the initial stages of staple formation. Advantageously, this allows the staples (692) to properly form within the clamped tissue, thereby maximizing hemostasis along the formed staple line.

[0095] 20 shows a line graph (900) illustrating exemplary curves representing actuation over time by the motor unit (660) of the trocar actuator (662), staple actuator (664), and knife actuator (666) during exemplary surgical procedures on thin, medium, and thick tissue. The anvil displacement curve (902) represents the longitudinal displacement over time of the trocar actuator (662) and thereby of the trocar (642) and anvil (650). The portion (904) below the dashed line of the anvil displacement curve (902) represents the original intended closure stroke of the anvil (650) before the closure member actuation algorithm was calibrated in the manner described above.

[0096] A first motor load curve (910) represents the current load on the motor unit (660) during actuation of the staple actuator (664), and thereby the staple driver member and its staple driver (690), to drive the staples (692) distally against the anvil (650) through thin tissue. A second motor load curve (912) represents the current load on the motor unit (660) during actuation of the staple actuator (664), and thereby the staple driver member and its staple driver (690), to drive the staples (692) distally against the anvil (650) through medium-thickness tissue. A third motor load curve (914) represents the current load on the motor unit (660) during actuation of the staple actuator (664), and thereby the staple driver member and its staple driver (690), to drive the staples (692) distally against the anvil (650) through thick tissue. A first knife displacement curve (920) represents the longitudinal displacement of the knife actuator (666) and thereby the knife member over time through thin tissue, a second knife displacement curve (922) represents the longitudinal displacement of the knife actuator (666) and thereby the knife member over time through medium-thickness tissue, and a third knife displacement curve (924) represents the longitudinal displacement of the knife actuator (666) and thereby the knife member over time through thick tissue.

[0097] As illustrated by the motor load curves 910, 912, 914 and knife displacement curves 920, 922, 924, the control module 672 of this embodiment is configured to control the motor unit 660 to actuate the staple actuator 664 and knife actuator 666 distally more slowly as tissue thickness increases. This is evident in the horizontally elongated shapes of the medium tissue curves 912, 922 and thick tissue curves 914, 924 relative to the thin tissue curves 910, 920 in graph 900. This approach ensures that the current load of the motor unit 660 does not exceed a predetermined threshold during the stapling and cutting stroke. From that point, as described above, distal actuation of the staple 692 and knife member through tissue of increasing thickness will result in the motor unit 660 drawing a higher current load.

[0098] Each motor load curve (910, 912, 914) includes a first rise (A) reflecting distal actuation of the staple actuator (664) through a first portion of the stapling stroke, which actuates the staple driver (690) from a fully recessed position (D0) shown in Figures 18-19B to an emerged position (D1), thus driving the staple (692) through the initial stages of formation against the anvil (650). Each motor load curve (910, 912, 914) further includes a second rise (B) reflecting distal actuation of the staple actuator (664) through a second portion of the stapling stroke, which actuates the staple driver (690) from the emergence position (D1) to the fully extended position (D2) shown in FIGS. 19B-19C, thus driving the staples (692) through the final stages of formation against the anvil (650). As shown by graph (900) for each of the three tissue thickness scenarios, the control module (672) begins distal actuation of the knife actuator (666) to perform the cutting stroke when the staple driver (690) reaches the emergence position (D1), which is represented by the motor load curve as a transition between the first curve portion (A) and the second curve portion (B). 18-19C, this approach of staggering the initiation of the stapling and cutting strokes helps reduce the risk of mis-forming staples, thus ensuring proper formation of the staples within the patient's tissue. In this example, graph 900 illustrates an exemplary time difference (Δt) between initiation of the knife actuator 666 in a procedure on thin tissue and initiation of the knife actuator 666 in a procedure on thick tissue.

[0099] In variations of circular stapler (600) in which sensor (674) includes a current sensor operably coupled to motor unit (660) in the manner described above, control module (672) may control the rate of actuation (or "speed") of one or more actuators (662, 664, 666) and their corresponding components based on the current drawn by motor unit (660) as sensed by the current sensor. For example, in response to an increase in the sensed current load above a predetermined threshold, control module (672) may reduce the rate of actuation of the actuators (662, 664, 666) being actuated. Similarly, in variations of stapler (600) in which sensor (674) includes a force sensor operably coupled to one or more of the trocar actuator (662), staple actuator (664), knife actuator (666), or their associated components (e.g., trocar (642)), control module (672) may be configured to reduce the actuation rate of a particular actuator (662, 664, 666) in response to detecting an increase in the longitudinal force exerted on that particular actuator (662, 664, 666) during its actuation.

[0100] It will be appreciated that the actuation rate of one or more actuators (662, 664, 666) may be controlled based on additional factors, such as the size of the stapling head assembly (640) or the target tissue gap specified by the user via the user interface (616). By way of example only, the control module (672) may decrease the actuation rate of one or more actuators (662, 664, 666) in the presence of a relatively large diameter stapling head assembly (640) and increase the actuation rate of one or more actuators (662, 664, 666) in the presence of a relatively small diameter stapling head assembly (640). Additionally, the control module (672) may decrease the actuation rate of one or more actuators (662, 664, 666) for larger tissue gaps and increase the actuation rate of one or more actuators (662, 664, 666) for smaller tissue gaps.

[0101] V. Exemplary Identification of the Stapling Head Assembly via Radio Frequency Identification As noted above, in some instances, particularly in instances in which a variety of different types of stapling head assemblies (640) are interchangeable with the shaft assembly (630), it may be desirable to sense certain characteristics (e.g., diameter) of the stapling head assembly (640) via a sensor (674) and communicate such information to the control module (672). As shown in FIG. 9, the end effectors (640, 650) of the surgical instrument (600) may include a radio frequency identification (RFID) tag (1000) configured to store information related to selected characteristics of the end effectors (640, 650). Additionally, one of the shaft assembly (630) or the handle assembly (610) may include a sensor (674) in the form of an RFID scanner configured to read information stored by the RFID tag (1000) and communicate such information to the control module (672). Based on such information, control module (672) may appropriately adjust one or more actuation algorithms of actuators (662, 664, 666) to ensure appropriate longitudinal displacement, actuation speed, and / or time pause between strokes of actuators (662, 664, 666), for example, as described in more detail below and in U.S. Provisional Patent Application No. 62 / 868,457, incorporated by reference above.

[0102] As shown in FIG. 21, graph 2260 depicts the relationship between firing load (pounds) on the Y-axis and firing time (seconds) on the X-axis. Graph 21 depicts a default unadjusted firing algorithm 2263 and an adjusted firing algorithm 2263. Graph 2260 further depicts a default maximum firing load threshold 2261 (e.g., 400 pounds) and a final maximum firing load threshold 2262 (e.g., 485 pounds) for the firing load applied by motor unit 660 to stapling head assembly 640 via staple actuator 664 and knife actuator 666. The default maximum firing load threshold (2261) is adjusted to a final maximum firing load threshold (2262) based on end effector information for the end effectors (640, 650) stored on the RFID tag (1000) of the stapling head assembly (640) and read by the RFID scanner (674). In the example of FIG. 21 , the end effector information represents a stapling head assembly (640) (or "staple cartridge") with a larger size (e.g., 31 mm) than the default staple cartridge (e.g., 25 mm). The default staple cartridge size (e.g., 25 mm) is associated with a default firing algorithm (2263) and a default maximum firing load threshold (2261). Meanwhile, the larger staple cartridge size (e.g., 31 mm) is associated with a final firing algorithm (2264) and a final maximum firing load threshold (2262).

[0103] The end effector information stored on RFID tag 1000 may include a staple cartridge size and / or a firing load adjustment value (e.g., 85 pounds) based on the cartridge size, in which case control module 672 may look up the appropriate firing load adjustment value using a database or lookup table of staple cartridge sizes and corresponding firing load adjustment values.

[0104] Additionally, as shown in FIG. 21, input from an RFID scanner (674) indicating end effector information causes the control module (672) to adjust the default maximum launch load threshold (2261) (e.g., 400) to the final maximum launch load threshold (2262) (e.g., 485 lbs) and maintain the firing algorithm (2264) below the final maximum launch load threshold (2262).

[0105] In the example of FIG. 21 , the control module 672 adjusts or implements a minimum wait time "t" before causing the motor unit 660 to apply the firing algorithm 2263 to the end effectors 640, 650. In various examples, the minimum wait time "t" is the period of time from the completion of the closing sequence of the end effectors of the surgical instrument 600, where tissue is grasped by the end effectors 640, 650 in a closed configuration, to the initiation of the firing sequence of the end effectors 640, 650, where the grasped tissue is stapled and severed. The minimum wait time "t" allows for tissue creep, where the grasped tissue adjusts to a lower average pressure, thereby reducing the maximum firing load required to complete the firing sequence of the end effectors 640, 650 to a value equal to or less than the final maximum firing load threshold 2262. In a default firing algorithm (2263) with no minimum wait time "t," the firing algorithm (2263) must be suspended (2267) for the period from time t3 to time t4 to prevent the firing load from exceeding the final maximum firing load threshold (2262). In comparison, as shown in FIG. 21, the firing algorithm (2264) continues throughout the period between t3 and t4.

[0106] With further reference to FIG. 21 , another factor that may affect the minimum wait time “t” is the user-selected forming height of the staples (692) deployed from the stapling head assembly (640), which, as described above, is directly proportional to the tissue gap distance defined by the anvil (650) in the closed position. Also as described above, the control module (672) may be configured to prompt the user via the user interface (616) to select a desired staple forming height (i.e., tissue gap). In at least one example, the control module (672) may present the user with multiple staple forming height options to select from. Additionally or alternatively, the control module (672) may recommend an optimal forming height based on the tissue being treated by the surgical instrument (600). In either case, the user-selected forming height may cause the control module (672) to further adjust the minimum wait time “t.” In at least one example, the control module (672) stores the forming heights and corresponding wait time adjustment values ​​in a database or lookup table. The control module (672) can adjust the minimum wait time "t" by identifying the wait time adjustment value associated with the user-selected forming height and then adjusting the minimum wait time "t" according to the identified wait time adjustment value.

[0107] Generally, larger formed staples are associated with larger firing loads and require a longer minimum wait time "t" than smaller formed staples. In the example of FIG. 21 , the user-selected form height (2265) is associated with firing load "F2" and is greater than the minimum form height (2266) associated with minimum firing load "F1." Minimum firing loads "F1" and "F2" represent the firing loads at which the staple legs begin to buckle. Thus, in the example shown in FIG. 21 , the selected wait time "t" is a result of the selected larger size staple cartridge and the selected form height (2265).

[0108] VI. Exemplary Combinations The following examples illustrate various, non-exhaustive, ways in which the teachings herein may be combined or applied. The following examples are not intended to limit the scope of any claims that may be presented at any time in this application or in a subsequent filing related to this application. No disclaimer is intended. The following examples are provided for illustrative purposes only. It is contemplated that the various teachings herein may be arranged and applied in many other ways. It is also contemplated that certain features referred to in the following examples may be omitted in some variations. Accordingly, none of the aspects or features referred to below should be deemed critical unless later expressly indicated as such by the inventors or their successors in title. If any claim presented in this application or in a subsequent filing related to this application includes additional features other than those referred to below, those additional features should not be deemed added for any reasons regarding patentability. [Example]

[0109] 1. A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly having a closure member, a staple driver member, and a knife member, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping tissue, the method comprising: (a) receiving, by the controller, a user input indicating a tissue gap defined by the stapling assembly in the closed state; and (b) controlling the motor unit based on the user input to operate the stapling assembly to close the stapling assembly. (c) with the staple fastening assembly in the closed state, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; (d) after initiating actuation of the staple driver member, determining with a controller that the staple driver member has reached a predetermined longitudinal position; and (e) in response to the determination, controlling the motor unit to actuate the knife member to cut the clamped tissue. [Example]

[0110] 2. The method of example 1, wherein the closure member, the staple driver member, and the knife member are actuatable by the motor unit independently of one another. [Example]

[0111] The method of example 1 or 2, wherein actuating the staple driver member to drive staples into the clamped tissue and actuating the knife member to cut the clamped tissue comprises actuating the staple driver member and the knife member distally relative to the motor unit. [Example]

[0112] The method of any one of Examples 1 to 3, wherein the stapling assembly includes an anvil, each staple includes a crown and a pair of legs, and the predetermined longitudinal position of the staple driver member includes a position where the legs are at least partially deformed by the anvil. [Example]

[0113] The method of example 4, wherein the stapling assembly includes a deck surface having a plurality of openings for accommodating staples, and the predetermined longitudinal position of the staple driver member includes a position where the crowns of the staples are positioned on the deck surface. [Example]

[0114] The method of any one of Examples 1 to 5, wherein the staple driver member is actuable distally through a stapling stroke and the knife member is actuable distally through a cutting stroke, and controlling the motor unit to initiate actuation of the knife member includes initiating the cutting stroke before completion of the stapling stroke. [Example]

[0115] 7. The method of any one of Examples 1-6, wherein the stapling assembly includes a sensor in communication with the controller, the method further including controlling actuation of at least one of the closure member, the staple driver member, or the knife member in response to a signal provided to the controller by the sensor. [Example]

[0116] 8. The method of example 7, further comprising detecting with a sensor that the staple driver member has reached a predetermined longitudinal position. [Example]

[0117] 9. The method of any one of Examples 1-8, further comprising detecting, with a sensor, that the tissue gap indicated by the user input has been achieved by the stapling assembly. [Example]

[0118] 10. The method of any of Examples 1-9, wherein the stapling assembly includes a current sensor operably coupled to the motor unit and the controller, the method further including controlling an actuation speed of at least one of the closure member, the staple driver member, or the knife member based on a signal provided by the current sensor, the signal indicative of a current drawn by the motor unit. [Example]

[0119] 11. The method of example 10, wherein controlling the actuation speed based on the signal provided by the current sensor includes decreasing the actuation speed in response to an increase in current drawn by the motor unit detected by the current sensor. [Example]

[0120] 12. The method of any of Examples 1-11, further comprising controlling the longitudinal displacement of at least one of the closure member, the staple driver member, or the knife member based on user input. [Example]

[0121] 13. The method of any one of examples 1-12, further comprising controlling an actuation speed of at least one of the closure member, the staple driver member, or the knife member based on user input. [Example]

[0122] The method of any of Examples 1 to 13, wherein the controller is configured to store and execute a closure member actuation algorithm for actuating the closure member via the motor unit to transition the stapling assembly to a closed state, and the method further includes: (a) comparing, by the controller, an actual longitudinal displacement of the closure member with an expected longitudinal displacement stored by the controller while actuating the closure member from the first longitudinal position to the second longitudinal position; (b) determining, by the controller, that the actual longitudinal displacement differs from the expected longitudinal displacement by a difference value; and (c) adjusting, by the controller, the closure member actuation algorithm based on the difference value. [Example]

[0123] 15. The method of any of Examples 1-14, wherein the controller is configured to store and execute a staple driver member actuation algorithm for actuating the staple driver member longitudinally to drive staples into the clamped tissue and a knife member actuation algorithm for actuating the knife member longitudinally to cut the clamped tissue, the method further comprising adjusting, by the controller, at least one of the staple driver member actuation algorithm or the knife member actuation algorithm based on the difference value. [Example]

[0124] 1. A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operably coupled to the motor unit, the stapling assembly including a closure member, a staple driver member, a knife member, a deck surface having a plurality of staple openings, and a plurality of staples housed within the staple openings, the stapling assembly being actuatable between an open state for receiving tissue and a closed state for clamping tissue, the method comprising: (a) controlling, by the controller, a closure member, a staple driver member, a knife member, a deck surface having a plurality of staple openings, and a plurality of staples housed within the staple openings, the stapling assembly being actuatable between an open state for receiving tissue and a closed state for clamping tissue; (b) based on the user input, controlling a motor unit to actuate a closure member to transition the stapling assembly to a closed state to define a tissue gap and clamp tissue therein; (c) with the stapling assembly in the closed state, controlling the motor unit to actuate a staple driver member to drive staples through the staple openings and into the clamped tissue; and (d) in response to the staples reaching a predetermined longitudinal position relative to a deck surface, controlling the motor unit to initiate actuation of a knife member to cut the clamped tissue. [Example]

[0125] 17. The method of example 16, wherein the stapling assembly includes a sensor in communication with the controller, the method further including detecting, with the sensor, that the staple has reached the predetermined longitudinal position. [Example]

[0126] 18. The method of example 16 or example 17, further comprising controlling at least one of an actuation speed of the knife member or a longitudinal displacement of the knife member based on user input. [Example]

[0127] 1. A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping tissue, the method including: (a) receiving, by the controller, a user input indicating a tissue gap defined by the stapling assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the stapling assembly to the closed state to define the tissue gap and clamp tissue therein; (c) with the stapling assembly in the closed state, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; and (d) after initiating actuation of the staple driver member, controlling the motor unit based on the user input to actuate the knife member to cut the clamped tissue. [Example]

[0128] 20. The method of claim 19, wherein controlling the motor unit to actuate the knife member based on the user input includes controlling at least one of the longitudinal displacement or actuation speed of the knife member based on the user input.

[0129] VII. Other It should also be understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein can be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. described herein. Thus, the above teachings, expressions, embodiments, examples, etc. should not be considered in isolation from one another. Various suitable ways in which the teachings herein can be combined will be readily apparent to those skilled in the art in light of the teachings herein. Such modifications and variations are intended to be within the scope of the appended claims.

[0130] Additionally, any one or more of the teachings herein may be combined with any one or more of the teachings disclosed in U.S. patent application Ser. No. [Attorney Docket No. END9128USNP1], entitled "Method for Calibrating Movements of Actuated Members of Powered Surgical Stapler," filed on the same day herewith, U.S. patent application Ser. No. [Attorney Docket No. END9130USNP1], entitled "Method for Controlling End Effector Closure for Powered Surgical Stapler," and U.S. patent application Ser. No. [Attorney Docket No. END9142USNP1], entitled "Anvil Retention and Release Features for Powered Circular Surgical Stapler," filed on the same day herewith, the disclosures of each of which are incorporated herein by reference.

[0131] It should be understood that the whole or part of any patent, publication, or other disclosure referred to herein as being incorporated by reference is incorporated herein only to the extent that the incorporated content does not contradict existing definitions, views, or other disclosure set forth in this disclosure. Accordingly, to the extent necessary, the disclosure explicitly set forth herein shall supersede any conflicting content incorporated herein by reference. Any content, or portion thereof, referred to herein as being incorporated by reference but that contradicts existing definitions, views, or other disclosure set forth herein is incorporated only to the extent that no conflict arises between the incorporated content and the existing disclosure.

[0132] Variations of the above-described devices can be applied not only to traditional medical procedures and surgeries performed by medical professionals, but also to robotic-assisted medical procedures and surgeries. By way of example only, the various teachings herein can be readily incorporated into robotic surgical systems such as the DAVINCI™ system by Intuitive Surgical, Inc. (Sunnyvale, California).

[0133] The above-described variations may be designed to be disposed of after a single use, or they may be designed to be used multiple times. In either or both cases, the variations may be reconditioned for reuse after at least one use. Reconditioning may include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular parts, and subsequent reassembly. In particular, some variations of the device may be disassembled, and any number of particular parts or components of the device may be selectively replaced or removed in any combination. Upon cleaning and / or replacement of particular parts, some variations of the device may be reassembled for subsequent use either at a reconditioning facility, or by the user immediately prior to a procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning / replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.

[0134] By way of example only, the variations described herein may be sterilized before and / or after treatment. In one sterilization technique, the device is placed in a sealed container, such as a plastic or TYVEK bag. The container and device may then be placed in a radiation field that can penetrate the container, such as gamma radiation, x-rays, or a high-energy electron beam. The radiation can kill bacteria on the device and in the container. The sterilized device may then be stored in the sterile container for later use. The device may also be sterilized using any other technique known in the art, including, but not limited to, beta or gamma radiation, ethylene oxide, or steam.

[0135] While various embodiments of the present invention have been shown and described, further adaptations of the methods and systems described herein may be realized by those skilled in the art through appropriate modifications without departing from the scope of the present invention. Some such possible modifications have been mentioned, and others will be apparent to those skilled in the art. For example, the above examples, embodiments, geometries, materials, dimensions, proportions, steps, etc. are illustrative and not required. Accordingly, it is understood that the scope of the present invention should be considered in light of the following claims and is not limited to the details of structure and operation shown and described in the specification and drawings.

[0136] [Embodiment] (1) A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly having a closure member, a staple driver member, and a knife member, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping tissue, the method comprising: (a) receiving, by the controller, a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the stapling assembly to the closed state to define the tissue gap and clamp tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; (d) determining, by the controller, after initiating actuation of the staple driver member, that the staple driver member has reached a predetermined longitudinal position; (e) in response to said determining, controlling said motor unit to initiate actuation of said knife member to cut said clamped tissue. (2) The method of claim 1, wherein the closure member, the staple driver member, and the knife member are operable by the motor unit independently of each other. (3) The method of embodiment 1, wherein actuating the staple driver member to drive staples into the clamped tissue and actuating the knife member to cut the clamped tissue comprises actuating the staple driver member and the knife member distally relative to the motor unit. (4) The method of embodiment 1, wherein the staple fastening assembly includes an anvil, each staple includes a crown and a pair of legs, and the predetermined longitudinal position of the staple driver member includes a position where the legs are at least partially deformed by the anvil. (5) The method of embodiment 4, wherein the staple fastening assembly includes a deck surface having a plurality of openings for accommodating the staples, and the predetermined longitudinal position of the staple driver member includes a position where the crowns of the staples are positioned on the deck surface.

[0137] (6) The method of embodiment 1, wherein the staple driver member is operable distally through a stapling stroke and the knife member is operable distally through a cutting stroke, and controlling the motor unit to initiate actuation of the knife member includes initiating the cutting stroke before completion of the stapling stroke. (7) The method of embodiment 1, wherein the stapling assembly includes a sensor in communication with the controller, and the method further includes controlling actuation of at least one of the closure member, the staple driver member, or the knife member in response to a signal provided to the controller by the sensor. (8) The method of claim 7, further comprising detecting, with the sensor, that the staple driver member has reached the predetermined longitudinal position. (9) The method of embodiment 7, further comprising detecting, by the sensor, that the tissue gap indicated by the user input has been achieved by the staple fastening assembly. (10) The method of embodiment 1, wherein the stapling assembly includes a current sensor operably coupled to the motor unit and the controller, and the method further includes controlling an actuation speed of at least one of the closure member, the staple driver member, or the knife member based on a signal provided by the current sensor, the signal being indicative of a current drawn by the motor unit.

[0138] (11) The method of claim 10, wherein controlling the operating speed based on the signal provided by the current sensor includes decreasing the operating speed in response to an increase in current drawn by the motor unit detected by the current sensor. (12) The method of embodiment 1, further comprising controlling longitudinal displacement of at least one of the closure member, the staple driver member, or the knife member based on the user input. (13) The method of claim 1, further comprising controlling an actuation speed of at least one of the closure member, the staple driver member, or the knife member based on the user input. (14) The controller is configured to store and execute a closure member actuation algorithm for actuating the closure member via the motor unit to transition the stapling assembly to the closed state, and the method includes: (a) comparing, by the controller, an actual longitudinal displacement of the closure member during actuation of the closure member from a first longitudinal position to a second longitudinal position with an expected longitudinal displacement stored by the controller; (b) determining, by the controller, that the actual longitudinal displacement differs from the expected longitudinal displacement by a difference value; (c) adjusting, by the controller, the closure member actuation algorithm based on the difference value. (15) The method of embodiment 14, wherein the controller is configured to store and execute a staple driver member actuation algorithm for longitudinally actuating the staple driver member to drive the staples into the clamped tissue and a knife member actuation algorithm for longitudinally actuating the knife member to cut the clamped tissue, the method further comprising adjusting, by the controller, at least one of the staple driver member actuation algorithm or the knife member actuation algorithm based on the difference value.

[0139] (16) A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly including a closure member, a staple driver member, a knife member, a deck surface having a plurality of staple openings, and a plurality of staples housed within the staple openings, the stapling assembly being actuatable between an open state for receiving tissue and a closed state for clamping tissue, the method comprising: (a) receiving, by the controller, a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the stapling assembly to the closed state to define the tissue gap and clamp tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive the staples through the staple openings and into the clamped tissue; (d) in response to the staple reaching a predetermined longitudinal position relative to the deck surface, controlling the motor unit to initiate actuation of the knife member to cut the clamped tissue. (17) The method of claim 16, wherein the stapling assembly includes a sensor in communication with the controller, the method further including detecting, by the sensor, that the staple has reached the predetermined longitudinal position. (18) The method of claim 16, further comprising controlling at least one of an actuation speed of the knife member or a longitudinal displacement of the knife member based on the user input. (19) A method of operating a powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly having a closure member, a staple driver member, and a knife member, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping tissue, the method comprising: (a) receiving, by the controller, a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the stapling assembly to the closed state to define the tissue gap and clamp tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; (d) after initiating actuation of the staple driver member, controlling the motor unit based on the user input to actuate the knife member to cut the clamped tissue. (20) The method of claim 19, wherein controlling the motor unit to actuate the knife member based on the user input includes controlling at least one of a longitudinal displacement or an actuation speed of the knife member based on the user input.

Claims

1. 1. A powered surgical stapler having: a motor unit; a controller in communication with the motor unit; and a stapling assembly operatively coupled to the motor unit, the stapling assembly having a closure member, a staple driver member, and a knife member, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping the tissue, the controller comprising: (a) receiving a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the staple fastening assembly to the closed state, defining the tissue gap and clamping the tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; (d) determining, after initiating actuation of the staple driver member, that the staple driver member has reached a predetermined longitudinal position; (e) in response to the determining, determining a wait period that is longer for a larger firing load corresponding to a size of the staple fastening assembly and a selected forming height of the staples, and controlling the motor unit to initiate actuation of the knife member to cut the clamped tissue after the wait period is completed; the closure member, the staple driver member, and the knife member are actuatable by the motor unit independently of one another; the controller is configured to actuate the knife member distally only when the staple driven by the staple driver member is at least partially formed within the tissue by the stapling assembly.

2. The powered surgical stapler of claim 1 , wherein the staple driver member and the knife member are configured to actuate distally relative to the motor unit.

3. 2. The powered surgical stapler of claim 1, wherein the stapling assembly includes an anvil, each staple includes a crown and a pair of legs, and the predetermined longitudinal position of the staple driver member includes a position at which the legs are at least partially deformed by the anvil.

4. 4. The powered surgical stapler of claim 3, wherein the stapling assembly includes a deck surface having a plurality of openings for accommodating the staples, and the predetermined longitudinal position of the staple driver member includes a position at which the crowns of the staples are positioned on the deck surface.

5. 2. The powered surgical stapler of claim 1, wherein the staple driver member is configured to actuate distally through a stapling stroke and the knife member is configured to actuate distally through a cutting stroke, and the controller is configured to control the motor unit to initiate the cutting stroke before completion of the stapling stroke.

6. 2. The powered surgical stapler of claim 1, wherein the stapling assembly includes a sensor in communication with the controller, the controller configured to control the motor unit to actuate at least one of the closure member, the staple driver member, or the knife member in response to a signal provided to the controller by the sensor.

7. The powered surgical stapler of claim 6, wherein the sensor is configured to detect when the staple driver member reaches the predetermined longitudinal position.

8. The powered surgical stapler of claim 6, wherein the sensor is configured to detect when the tissue gap indicated by the user input has been achieved by the stapling assembly.

9. 2. The powered surgical stapler of claim 1, wherein the stapling assembly includes a current sensor operatively coupled to the motor unit and the controller, the controller configured to control a speed of actuation of at least one of the closure member, the staple driver member, or the knife member based on a signal provided by the current sensor, the signal indicative of a current drawn by the motor unit.

10. 10. The powered surgical stapler of claim 9, wherein the controller is configured to decrease the actuation speed in response to an increase in current drawn by the motor unit sensed by the current sensor.

11. 10. The powered surgical stapler of claim 1, wherein the controller is configured to control longitudinal displacement of at least one of the closure member, the staple driver member, or the knife member based on the user input.

12. 10. The powered surgical stapler of claim 1, wherein the controller is configured to control a speed of actuation of at least one of the closure member, the staple driver member, or the knife member based on the user input.

13. The controller is configured to store and execute a closure member actuation algorithm for actuating the closure member via the motor unit to transition the stapling assembly to the closed state, the controller comprising: (a) comparing an actual longitudinal displacement of the closure member with an expected longitudinal displacement stored by the controller during actuation of the closure member from a first longitudinal position to a second longitudinal position; (b) determining that the actual longitudinal displacement differs from the expected longitudinal displacement by a difference value; The powered surgical stapler of claim 1 , further configured: (c) adjusting the closure member actuation algorithm based on the difference value.

14. 14. The powered surgical stapler of claim 13, wherein the controller is configured to store and execute a staple driver member actuation algorithm for longitudinally actuating the staple driver member to drive the staples into the clamped tissue and a knife member actuation algorithm for longitudinally actuating the knife member to cut the clamped tissue, and the controller is configured to adjust at least one of the staple driver member actuation algorithm or the knife member actuation algorithm based on the difference value.

15. 1. A powered surgical stapler having a motor unit, a controller in communication with the motor unit, and a stapling assembly operatively coupled to the motor unit, the stapling assembly including a closure member, a staple driver member, a knife member, a deck surface having a plurality of staple openings, and a plurality of staples housed within the staple openings, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping the tissue, the controller comprising: (a) receiving a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the staple fastening assembly to the closed state, defining the tissue gap and clamping the tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive the staple through the staple openings and into the clamped tissue; (d) in response to the staples reaching a predetermined longitudinal position relative to the deck surface, determine a wait period that is longer for a larger firing load corresponding to a size of the staple fastening assembly and a selected formed height of the staples, and upon completion of the wait period, control the motor unit to initiate actuation of the knife member to cut the clamped tissue; the closure member, the staple driver member, and the knife member are actuatable by the motor unit independently of one another; the controller is configured to actuate the knife member distally only when the staple driven by the staple driver member is at least partially formed within the tissue by the stapling assembly.

16. 16. The powered surgical stapler of claim 15, wherein the stapling assembly includes a sensor in communication with the controller, the sensor configured to detect when the staple reaches the predetermined longitudinal position.

17. 16. The powered surgical stapler of claim 15, wherein the controller is configured to control at least one of an actuation speed of the knife member or a longitudinal displacement of the knife member based on the user input.

18. 1. A powered surgical stapler having: a motor unit; a controller in communication with the motor unit; and a stapling assembly operatively coupled to the motor unit, the stapling assembly having a closure member, a staple driver member, and a knife member, the stapling assembly being actuable between an open state for receiving tissue and a closed state for clamping the tissue, the controller comprising: (a) receiving a user input indicating a tissue gap defined by the staple fastening assembly in the closed state; (b) based on the user input, controlling the motor unit to actuate the closure member to transition the staple fastening assembly to the closed state, defining the tissue gap and clamping the tissue therein; (c) with the stapling assembly in the closed condition, controlling the motor unit to actuate the staple driver member to drive staples into the clamped tissue; (d) in response to the staples reaching a predetermined longitudinal position relative to a deck surface of the stapling assembly after initiating actuation of the staple driver member, determine a wait period that is longer for a larger firing load corresponding to a size of the stapling assembly and a selected forming height of the staples, and upon completion of the wait period, control the motor unit based on the user input to actuate the knife member to cut the clamped tissue; the closure member, the staple driver member, and the knife member are actuatable by the motor unit independently of one another; the controller is configured to actuate the knife member distally only when the staple driven by the staple driver member is at least partially formed within the tissue by the stapling assembly.

19. 20. The powered surgical stapler of claim 18, wherein the controller is configured to control at least one of the longitudinal displacement or actuation speed of the knife member based on the user input.

Images