Patent Description:
One example of an instrument that may be used to provide an anastomosis is a circular stapler. Some such staplers are operable to clamp down on layers of tissue, cut through the clamped layers of tissue, and drive staples through the clamped layers of tissue to substantially seal the layers of tissue together near the severed ends of the tissue layers, thereby joining the two severed ends of the anatomical lumen together. The circular stapler may be configured to sever the tissue and seal the tissue substantially simultaneously. For instance, the circular stapler may sever excess tissue that is interior to an annular array of staples at an anastomosis, to provide a substantially smooth transition between the anatomical lumen sections that are joined at the anastomosis. Circular staplers may be used in open procedures or in endoscopic procedures. In some instances, a portion of the circular stapler is inserted through a patient's naturally occurring orifice.

Examples of circular staplers are described in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>; and <CIT>.

Some circular staplers may include a motorized actuation mechanism. Examples of circular staplers with motorized actuation mechanisms are described in <CIT>, now abandoned; <CIT>; <CIT>; and <CIT>.

<CIT> relates to a surgical stapling device that includes a housing (, an outer tube extending distally from the housing, a disposable staple assembly releasably supported on a distal end of the outer tube, an approximation assembly operably received within the housing, and a staple pusher assembly extending from within the housing to the distal end of the outer tube.

<CIT> relates to a surgical cutting and stapling instrument. The surgical instrument has a handle with a moveable firing trigger, a shaft extending from the handle, and a stapling head at the end of the shaft. An array of staples are located within the stapling head.

<CIT> relates to a surgical stapling instrument for performing a circular anastomosis stapling operation. The surgical instrument includes a stapling head assembly mounted by a flexible support shaft to an actuator handle assembly.

<CIT> relates to a medical suturing apparatus that comprises a main body that consists of an operating member and an insertion member extending therefrom and an anvil head that is provided at the distal end of the main body for clinching a plurality of staples.

<CIT> relates to a circular stapling instrument including a stapling forming assembly that is actuated independently from actuation of the cutting assembly is provided. The instrument includes a handle assembly, an elongate body extending from the handle assembly, a cartridge assembly mounted on a distal end of the elongate body.

<CIT> relates to a rotatable cutter head of a surgical stapler that includes a staple housing, staple drivers, a cutter, a staple driving post, a staple cartridge and a rotatable member. The above members constitute a driving device of the cutter and the driving device is a rotatable driving device.

<CIT> relates to an apparatus that includes a body, a shaft, a stapling head assembly, and an anvil. The body includes a motor, a first user input feature, and a second user input feature. The first user input feature is operable to activate the motor. The shaft extends distally from the body. The stapling head assembly is positioned at a distal end of the shaft.

Optional features are recited in the dependent claims.

The drawings are not intended to be limiting in any way, and it is contemplated that the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings.

The drawings and descriptions should be regarded as illustrative in nature and not restrictive.

This application refers to the disclosures of <CIT>, now abandoned; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>.

<FIG> depict an exemplary surgical circular stapling instrument (<NUM>) that may be used to provide an end-to-end, side-to-side, or end-to-side anastomosis between two sections of an anatomical lumen such as a portion of a patient's digestive tract. Instrument (<NUM>) of this example comprises a handle assembly (<NUM>), a shaft assembly (<NUM>), a stapling head assembly (<NUM>), and an anvil (<NUM>). Handle assembly (<NUM>) comprises a casing (<NUM>) defining an obliquely oriented pistol grip (<NUM>). In some versions, pistol grip (<NUM>) is perpendicularly oriented. In some other versions, pistol grip (<NUM>) is omitted. Handle assembly (<NUM>) further includes a user feedback feature (<NUM>). In some versions, a series of hash marks, colored regions, and/or other fixed indicators are positioned adjacent to user feedback feature (<NUM>). Various suitable alternative features and configurations for handle assembly (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

Instrument (<NUM>) of the present example further includes a battery pack (<NUM>). Battery pack (<NUM>) is operable to provide electrical power to a motor (not shown) in pistol grip (<NUM>) as will be described in greater detail below. Battery pack (<NUM>) is removable from handle assembly (<NUM>). In particular, as shown in <FIG>, battery pack (<NUM>) may be inserted into a socket (<NUM>) defined by casing (<NUM>). Once battery pack (<NUM>) is fully inserted in socket (<NUM>), latches (<NUM>) of battery pack (<NUM>) may resiliently engage interior features of casing (<NUM>) to provide a snap fit. To remove battery pack (<NUM>), the operator may press latches (<NUM>) inwardly to disengage latches (<NUM>) from the interior features of casing (<NUM>) then pull battery pack (<NUM>) proximally from socket (<NUM>). It should be understood that battery pack (<NUM>) and handle assembly (<NUM>) may have complementary electrical contacts, pins and sockets, and/or other features that provide paths for electrical communication from battery pack (<NUM>) to electrically powered components in handle assembly (<NUM>) when battery pack (<NUM>) is inserted in socket (<NUM>). It should also be understood that, in some versions, battery pack (<NUM>) is unitarily incorporated within handle assembly (<NUM>) such that battery pack (<NUM>) cannot be removed from handle assembly (<NUM>).

Shaft assembly (<NUM>) extends distally from handle assembly (<NUM>) and includes a preformed bend. In some versions, the preformed bend is configured to facilitate positioning of stapling head assembly (<NUM>) within a patient's colon. Various suitable bend angles or radii that may be used will be apparent to those of ordinary skill in the art in view of the teachings herein. In some other versions, shaft assembly (<NUM>) is straight, such that shaft assembly (<NUM>) lacks a preformed bend. Various exemplary components that may be incorporated into shaft assembly (<NUM>) will be described in greater detail below.

Stapling head assembly (<NUM>) is located at the distal end of shaft assembly (<NUM>). As shown in <FIG> and as will be described in greater detail below, anvil (<NUM>) is configured to removably couple with shaft assembly (<NUM>), adjacent to stapling head assembly (<NUM>). As will also be described in greater detail below, anvil (<NUM>) and stapling head assembly (<NUM>) are configured to cooperate to manipulate tissue in three ways, including clamping the tissue, cutting the tissue, and stapling the tissue. A knob (<NUM>) at the proximal end of handle assembly (<NUM>) is rotatable relative to casing (<NUM>) to provide precise clamping of the tissue between anvil (<NUM>) and stapling head assembly (<NUM>). When a safety trigger (<NUM>) of handle assembly (<NUM>) is pivoted away from a firing trigger (<NUM>) of handle assembly (<NUM>), firing trigger (<NUM>) may be actuated to thereby provide cutting and stapling of the tissue.

<FIG> shows various components of shaft assembly (<NUM>), which couples components of stapling head assembly (<NUM>) with components of handle assembly (<NUM>). In particular, and as noted above, shaft assembly (<NUM>) includes an outer sheath (<NUM>) that extends between handle assembly (<NUM>) and a body member (<NUM>). In the present example, outer sheath (<NUM>) is rigid and includes a preformed curved section as noted above.

Shaft assembly (<NUM>) further includes a trocar actuation rod (<NUM>) and a trocar actuation band assembly (<NUM>). The distal end of trocar actuation band assembly (<NUM>) is fixedly secured to the proximal end of a shaft (<NUM>) of a trocar (<NUM>). The proximal end of trocar actuation band assembly (<NUM>) is fixedly secured to the distal end of trocar actuation rod (<NUM>). It should therefore be understood that trocar (<NUM>) will translate longitudinally relative to outer sheath (<NUM>) in response to translation of trocar actuation band assembly (<NUM>) and trocar actuation rod (<NUM>) relative to outer sheath (<NUM>). Trocar actuation band assembly (<NUM>) is configured to flex such that trocar actuation band assembly (<NUM>) may follow along the preformed curve in shaft assembly (<NUM>) as trocar actuation band assembly (<NUM>) is translated longitudinally relative to outer sheath (<NUM>). However, trocar actuation band assembly (<NUM>) has sufficient column strength and tensile strength to transfer distal and proximal forces from trocar actuation rod (<NUM>) to shaft (<NUM>) of trocar (<NUM>). Trocar actuation rod (<NUM>) is rigid. A clip (<NUM>) is fixedly secured to trocar actuation rod (<NUM>) and is configured to cooperate with complementary features within handle assembly (<NUM>) to prevent trocar actuation rod (<NUM>) from rotating within handle assembly (<NUM>) while still permitting trocar actuation rod (<NUM>) to translate longitudinally within handle assembly (<NUM>). Trocar actuation rod (<NUM>) further includes a coarse helical threading (<NUM>) and a fine helical threading (<NUM>).

Shaft assembly (<NUM>) further includes a stapling head assembly driver (<NUM>) that is slidably received within outer sheath (<NUM>). The distal end of stapling head assembly driver (<NUM>) is fixedly secured to the proximal end of staple driver member (<NUM>). The proximal end of stapling head assembly driver (<NUM>) is secured to a drive bracket (<NUM>) via a pin (<NUM>). It should therefore be understood that staple driver member (<NUM>) will translate longitudinally relative to outer sheath (<NUM>) in response to translation of stapling head assembly driver (<NUM>) and drive bracket (<NUM>) relative to outer sheath (<NUM>). Stapling head assembly driver (<NUM>) is configured to flex such that stapling head assembly driver (<NUM>) may follow along the preformed curve in shaft assembly (<NUM>) as stapling head assembly driver (<NUM>) is translated longitudinally relative to outer sheath (<NUM>). However, stapling head assembly driver (<NUM>) has sufficient column strength to transfer distal forces from drive bracket (<NUM>) to staple driver member (<NUM>). Drive bracket (<NUM>) includes notches (<NUM>).

While not shown in <FIG>, it should be understood that shaft assembly (<NUM>) may further include one or more spacer elements within outer sheath (<NUM>). Such spacer elements may be configured to support trocar actuation band assembly (<NUM>) and/or stapling head assembly driver (<NUM>) as trocar actuation band assembly (<NUM>) and/or stapling head assembly driver (<NUM>) translate through outer sheath (<NUM>). For instance, such spacer elements may prevent trocar actuation band assembly (<NUM>) and/or stapling head assembly driver (<NUM>) from buckling as trocar actuation band assembly (<NUM>) and/or stapling head assembly driver (<NUM>) translate through outer sheath (<NUM>). Various suitable forms that such spacer elements may take will be apparent to those of ordinary skill in the art in view of the teachings herein.

As shown in <FIG>, handle assembly (<NUM>) includes several components that are operable to actuate anvil (<NUM>) and stapling head assembly (<NUM>). Handle assembly (<NUM>) also includes components that are operable to selectively lock out triggers (<NUM>, <NUM>) based on the position of anvil (<NUM>) relative to stapling head assembly (<NUM>). When triggers (<NUM>, <NUM>) are locked out, firing trigger (<NUM>) is prevented from initiating actuation of stapling head assembly (<NUM>). Thus, firing trigger (<NUM>) is only operable to initiate actuation of stapling head assembly (<NUM>) when the position of anvil (<NUM>) relative to stapling head assembly (<NUM>) is within a predefined range. The components of handle assembly (<NUM>) that provide the foregoing operability will be described in greater detail below.

In the following discussion of anvil (<NUM>), the terms "distal" and "proximal" (and variations thereof) will be used with reference to the orientation of anvil (<NUM>) when anvil (<NUM>) is coupled with shaft assembly (<NUM>) of instrument (<NUM>). Thus, proximal features of anvil (<NUM>) will be closer to the operator of instrument (<NUM>); while distal features of anvil (<NUM>) will be further from the operator of instrument (<NUM>).

As best seen in <FIG>, anvil (<NUM>) of the present example comprises a head (<NUM>) and a shank (<NUM>). Head (<NUM>) includes a proximal surface (<NUM>) that defines a plurality of staple forming pockets (<NUM>). Staple forming pockets (<NUM>) are arranged in two concentric annular arrays in the present example. In some other versions, staple forming pockets (<NUM>) are arranged in three or more concentric annular arrays. Staple forming pockets (<NUM>) are configured to deform staples as the staples are driven into staple forming pockets (<NUM>). For instance, each staple forming pocket (<NUM>) may deform a generally "U" shaped staple into a "B" shape as is known in the art. As best seen in <FIG>, proximal surface (<NUM>) terminates at an inner edge (<NUM>), which defines an outer boundary of an annular recess (<NUM>) surrounding shank (<NUM>).

Shank (<NUM>) defines a bore (<NUM>) and includes a pair of pivoting latch members (<NUM>) positioned in bore (<NUM>). As best seen in <FIG>, each latch member (<NUM>) includes a "T" shaped distal end (<NUM>), a rounded proximal end (<NUM>), and a latch shelf (<NUM>) located distal to proximal end (<NUM>). "T" shaped distal ends (<NUM>) secure latch members (<NUM>) within bore (<NUM>). Latch members (<NUM>) are positioned within bore (<NUM>) such that proximal ends (<NUM>) are positioned at the proximal ends of lateral openings (<NUM>), which are formed through the sidewall of shank (<NUM>). Lateral openings (<NUM>) thus provide clearance for proximal ends (<NUM>) and latch shelves (<NUM>) to deflect radially outwardly from the longitudinal axis defined by shank (<NUM>). However, latch members (<NUM>) are configured to resiliently bias proximal ends (<NUM>) and latch shelves (<NUM>) to pivot radially inwardly toward the longitudinal axis defined by shank (<NUM>). Latch members (<NUM>) thus act as retaining clips. This allows anvil (<NUM>) to be removably secured to trocar (<NUM>) of stapling head assembly (<NUM>) as will be described in greater detail below. It should be understood, however, that latch shelves (<NUM>) are merely optional. Anvil (<NUM>) may be removably secured to trocar (<NUM>) using any other suitable components, features, or techniques.

As best seen in <FIG>, shank (<NUM>) of the present example includes a set of longitudinally extending splines (<NUM>) that are spaced about shank (<NUM>) in an angular array. The proximal end of each spline (<NUM>) includes a respective lead-in edge (<NUM>). A plurality of longitudinally extending splines (<NUM>) (see <FIG>) are equidistantly spaced in an angular array within bore (<NUM>). As described in greater detail below, splines (<NUM>) are configured to engage corresponding splines (<NUM>) of body member (<NUM>) of stapling head assembly (<NUM>) in order to consistently provide a predetermined angular alignment between anvil (<NUM>) and stapling head assembly (<NUM>). As also described below, this angular alignment may ensure that staple forming pockets (<NUM>) of anvil (<NUM>) are consistently angularly aligned appropriately with staple openings (<NUM>) of stapling head assembly (<NUM>).

In some instances, it may be desirable to change the configuration and arrangement of staple forming pockets (<NUM>) in anvil (<NUM>). It should be understood that reconfiguring and rearranging staple forming pockets (<NUM>) may result in reconfiguration and rearrangement of staples (<NUM>) that are formed by staple forming pockets (<NUM>). For instance, the configuration and arrangement of staple forming pockets (<NUM>) may affect the structural integrity of an anastomosis (<NUM>) that is secured by staples (<NUM>). In addition, the configuration and arrangement of staple forming pockets (<NUM>) may affect the hemostasis that is achieved at an anastomosis (<NUM>) that is secured by staples (<NUM>). The following description relates to several exemplary variations of anvil (<NUM>), providing staple forming pocket configurations and arrangements that differ from those of staple forming pockets (<NUM>). Various suitable ways in which the alternatives to anvil (<NUM>) described below may be incorporated into instrument (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

For example, the staples formed using an exemplary alternative anvil may have an appearance similar to at least some of the staples shown and described in <CIT>. By way of further example only, the staples formed may have an appearance similar to at least some of the staples shown and described in <CIT>.

In addition to or in lieu of the foregoing, anvil (<NUM>) may be further constructed and operable in accordance with at least some of the teachings of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>. Still other suitable configurations will be apparent to one of ordinary skill in the art in view of the teachings herein.

As best seen in <FIG>, stapling head assembly (<NUM>) of the present example is coupled to a distal end of shaft assembly (<NUM>) and comprises body member (<NUM>) and a slidable staple driver member (<NUM>). Body member (<NUM>) includes a distally extending cylindraceous inner core member (<NUM>). Body member (<NUM>) is fixedly secured to an outer sheath (<NUM>) of shaft assembly (<NUM>). Body member (<NUM>) and outer sheath (<NUM>) thus serve together as a mechanical ground for stapling head assembly (<NUM>).

As shown in <FIG>, inner core member (<NUM>) of body member (<NUM>) defines a bore (<NUM>). When shank (<NUM>) is secured to trocar (<NUM>) and trocar (<NUM>) is retracted proximally, the inner diameter of bore (<NUM>) in inner core member (<NUM>) of body member (<NUM>) laterally constrains latch members (<NUM>) to maintain engagement between latch shelves (<NUM>) and proximal surface (<NUM>) of a head (<NUM>) of trocar (<NUM>). This engagement prevents anvil (<NUM>) from being released from trocar (<NUM>) during firing of stapling head assembly (<NUM>). The distal ends of splines (<NUM>) include lead-in edges (<NUM>) that are configured to complement lead-in edges (<NUM>) of splines (<NUM>) on shank (<NUM>) of anvil (<NUM>). In particular, after shank (<NUM>) is secured to trocar (<NUM>) as described in greater detail below, and as anvil (<NUM>) is thereafter retracted proximally relative to stapling head assembly (<NUM>) as also described in greater detail below, lead-in edges (<NUM>, <NUM>) may cooperatively engage each other to drive anvil (<NUM>) to rotate relative to trocar (<NUM>) to angularly align splines (<NUM>) of anvil (<NUM>) with the gaps between splines (<NUM>) of body member (<NUM>). Thus, splines (<NUM>, <NUM>) are configured to cooperate with each other to ensure that staples ejected through staple openings (<NUM>) are accurately driven into corresponding staple forming pockets (<NUM>) on a consistent basis, regardless of the angular orientation of anvil (<NUM>) relative to stapling head assembly (<NUM>) at the time anvil (<NUM>) is initially secured to trocar (<NUM>).

Trocar (<NUM>) is positioned coaxially within inner core member (<NUM>) of body member (<NUM>). As will be described in greater detail below, trocar (<NUM>) is operable to translate distally and proximally relative to body member (<NUM>) in response to rotation of knob (<NUM>) relative to casing (<NUM>) of handle assembly (<NUM>). Trocar (<NUM>) comprises a shaft (<NUM>) and head (<NUM>). Head (<NUM>) includes a pointed tip (<NUM>) and an inwardly extending proximal surface (<NUM>). Shaft (<NUM>) thus provides a reduced outer diameter just proximal to head (<NUM>), with proximal surface (<NUM>) providing a transition between that reduced outer diameter of shaft (<NUM>) and the outer diameter of head (<NUM>). While tip (<NUM>) is pointed in the present example, tip (<NUM>) is not sharp. Tip (<NUM>) will thus not easily cause trauma to tissue due to inadvertent contact with tissue. Head (<NUM>) and the distal portion of shaft (<NUM>) are configured for insertion in bore (<NUM>) of anvil (<NUM>). Proximal surface (<NUM>) and latch shelves (<NUM>) have complementary positions and configurations such that latch shelves (<NUM>) engage proximal surface (<NUM>) when shank (<NUM>) of anvil (<NUM>) is fully seated on trocar (<NUM>). Anvil (<NUM>) is thus secured to trocar (<NUM>) through a snap fit due to latch members (<NUM>).

Staple driver member (<NUM>) is operable to actuate longitudinally within body member (<NUM>) in response to activation of the motor as will be described in greater detail below. Staple driver member (<NUM>) includes two distally presented concentric annular arrays of staple drivers (<NUM>). Staple drivers (<NUM>) are arranged to correspond with the arrangement of staple forming pockets (<NUM>) described above. Thus, each staple driver (<NUM>) is configured to drive a corresponding staple into a corresponding staple forming pocket (<NUM>) when stapling head assembly (<NUM>) is actuated. It should be understood that the arrangement of staple drivers (<NUM>) may be modified just like the arrangement of staple forming pockets (<NUM>) as described above. Staple driver member (<NUM>) also defines a bore (<NUM>) that is configured to coaxially receive inner core member (<NUM>) of body member (<NUM>). An annular array of studs (<NUM>) project distally from a distally presented surface surrounding bore (<NUM>).

A knife member (<NUM>) is coaxially positioned within staple driver member (<NUM>). Knife member (<NUM>) includes a distally presented, sharp circular cutting edge (<NUM>). Knife member (<NUM>) is sized such that knife member (<NUM>) defines an outer diameter that is smaller than the diameter defined by the inner annular array of staple drivers (<NUM>). Knife member (<NUM>) has a cylindrical wall (<NUM>) integrally together formed with a proximal flange (<NUM>). Proximal flange (<NUM>) extends radially inwardly relative to cylindrical wall (<NUM>). An inner diameter of proximal flange (<NUM>) of knife member (<NUM>) defines an opening (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). Proximal flange (<NUM>) includes an annular array of openings (<NUM>). Annular array of openings (<NUM>) formed in knife member (<NUM>) is configured to complement the annular array of studs (<NUM>) of staple driver member (<NUM>), such that knife member (<NUM>) is fixedly secured to staple driver member (<NUM>) via studs (<NUM>) and openings (<NUM>). By way of example only, studs (<NUM>) may be heat staked to knife member (<NUM>) using techniques known in the art. Other suitable structural relationships between knife member (<NUM>) and staple driver member (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

A deck member (<NUM>) is fixedly secured to body member (<NUM>). Deck member (<NUM>) includes a distally presented deck surface (<NUM>) defining two concentric annular arrays of staple openings (<NUM>). Staple openings (<NUM>) are arranged to correspond with the arrangement of staple drivers (<NUM>) and staple forming pockets (<NUM>) described above. Thus, each staple opening (<NUM>) is configured to provide a path for a corresponding staple driver (<NUM>) to drive a corresponding staple through deck member (<NUM>) and into a corresponding staple forming pocket (<NUM>) when stapling head assembly (<NUM>) is actuated. It should also be understood that, in some instances, the configuration and arrangement of staple openings (<NUM>) in deck member (<NUM>) may be modified just like the arrangement of staple forming pockets (<NUM>). It should also be understood that various structures and techniques may be used to contain staples within stapling head assembly (<NUM>) before stapling head assembly (<NUM>) is actuated. Such structures and techniques that are used to contain staples within stapling head assembly (<NUM>) may prevent the staples from inadvertently falling out through staple openings (<NUM>) before stapling head assembly (<NUM>) is actuated. Various suitable forms that such structures and techniques may take will be apparent to those of ordinary skill in the art in view of the teachings herein. As best seen in <FIG>, deck member (<NUM>) defines an inner diameter that is just slightly larger than the outer diameter defined by knife member (<NUM>). Deck member (<NUM>) is thus configured to allow knife member (<NUM>) to translate distally to a point where cutting edge (<NUM>) is distal to deck surface (<NUM>).

<FIG> show a first exemplary alternative knife member (<NUM>) and a first exemplary alternative staple driver member (<NUM>) that may be used with a modified version of instrument (<NUM>). Particularly, <FIG> shows an exploded perspective view of knife member (<NUM>) and staple driver member (<NUM>), and <FIG> shows a top plan view of knife member (<NUM>) and staple driver member (<NUM>) of <FIG>. Knife member (<NUM>) and staple driver member (<NUM>) of this example are configured and operable like knife member (<NUM>) and staple driver member (<NUM>) described in detail above, except for the differences described below.

Similar to staple driver member (<NUM>), staple driver member (<NUM>) is operable to actuate longitudinally within a body member (e.g., body member (<NUM>)) in response to activation of the motor. Staple driver member (<NUM>) includes two distally presented concentric annular arrays of staple drivers (<NUM>). Staple drivers (<NUM>) are arranged to correspond with the arrangement of staple forming pockets (similar to staple forming pockets (<NUM>)) described above. Staple driver member (<NUM>) defines a bore (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). An annular array of studs (<NUM>) project distally from a distally presented surface surrounding bore (<NUM>).

Similar to knife member (<NUM>), knife member (<NUM>) may be coaxially positioned within staple driver member (<NUM>). Knife member (<NUM>) includes a distally presented, sharp circular cutting edge (<NUM>). Knife member (<NUM>) includes a body (<NUM>). Body (<NUM>) has a cylindrical wall (<NUM>) integrally together formed with a proximal flange (<NUM>). Proximal flange (<NUM>) extends radially inwardly relative to cylindrical wall (<NUM>). An inner diameter of proximal flange (<NUM>) of knife member (<NUM>) defines an opening (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). Proximal flange (<NUM>) includes an annular array of openings (<NUM>).

The annular array of openings (<NUM>) formed in knife member (<NUM>) is configured to complement the annular array of studs (<NUM>) of staple driver member (<NUM>), such that knife member (<NUM>) is fixedly secured to staple driver member (<NUM>) via studs (<NUM>) and openings (<NUM>). Particularly, <FIG> shows six individual studs (<NUM>) of staple driver member (<NUM>) that are disposed in six respective openings (<NUM>) of knife member (<NUM>). By way of example only, studs (<NUM>) may be heat staked to knife member (<NUM>) using techniques known in the art. Knife member (<NUM>) and staple driver member (<NUM>) may be driven distally as similarly shown in <FIG> regarding stapling head assembly (<NUM>). As knife member (<NUM>) translates distally, cutting edge (<NUM>) of knife member (<NUM>) cuts excess tissue that is positioned within an annular recess (e.g., annular recess (<NUM>) of anvil (<NUM>)) and the interior of knife member (<NUM>).

In some versions of instrument (<NUM>) it may desirable to provide instrument (<NUM>) with features that are configured to indicate proper and/or improper attachment of anvil (<NUM>) to trocar (<NUM>) of stapling head assembly (<NUM>). In the example shown in <FIG>, trocar (<NUM>) includes a colored region (<NUM>) that is longitudinally positioned at a location where colored region (<NUM>) is exposed before shank (<NUM>) is fully seated on trocar (<NUM>) (<FIG>); and covered when shank (<NUM>) is fully seated on trocar (<NUM>) (<FIG>).

In addition to or in lieu of the foregoing, stapling head assembly (<NUM>) may be further constructed and operable in accordance with at least some of the teachings of <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and/or <CIT>. Still other suitable configurations will be apparent to one of ordinary skill in the art in view of the teachings herein.

It may be desirable to provide a version of stapling head assembly (<NUM>) that includes features that enhance gripping of tissue during actuation of stapling head assembly (<NUM>), thereby promoting successful tissue cutting and staple deployment, without increasing the risk of damaging the patient's tissue as stapling head assembly (<NUM>) slides along the tissue during positioning of stapling head assembly (<NUM>). By way of further example only, one such deck member is shown and described in <CIT>.

<FIG> show instrument (<NUM>) being used to form an anastomosis (<NUM>) between two tubular anatomical structures (<NUM>, <NUM>). By way of example only, the tubular anatomical structures (<NUM>, <NUM>) may comprise sections of a patient's esophagus, sections of a patient's colon, other sections of the patient's digestive tract, or any other tubular anatomical structures. As shown in <FIG>, anvil (<NUM>) is positioned in one tubular anatomical structure (<NUM>) and stapling head assembly (<NUM>) is positioned in another tubular anatomical structure (<NUM>). In versions where tubular anatomical structures (<NUM>, <NUM>) comprise sections of a patient's colon, stapling head assembly (<NUM>) may be inserted via the patient's rectum. It should also be understood that the procedure depicted in <FIG> is an open surgical procedure, though the procedure may instead be performed laparoscopically. Various suitable ways in which instrument (<NUM>) may be used to form an anastomosis (<NUM>) in a laparoscopic procedure will be apparent to those of ordinary skill in the art in view of the teachings herein.

As shown in <FIG>, anvil (<NUM>) is positioned in tubular anatomical structure (<NUM>) such that shank (<NUM>) protrudes from the open severed end (<NUM>) of tubular anatomical structure (<NUM>). In the present example, purse-string suture (<NUM>) is provided about a mid-region of shank (<NUM>) to generally secure the position of anvil (<NUM>) in tubular anatomical structure (<NUM>). In some other variations, purse-string suture (<NUM>) is tightened around the proximal end of shank (<NUM>). In some such variations, the proximal end of shank (<NUM>) may include a notch or other feature to securely capture purse-string suture (<NUM>). Continuing with the present example, stapling head assembly (<NUM>) is positioned in tubular anatomical structure (<NUM>) such that trocar (<NUM>) protrudes from the open severed end (<NUM>) of tubular anatomical structure (<NUM>). A purse-string suture (<NUM>) is provided about a mid-region of shaft (<NUM>) to generally secure the position of stapling head assembly (<NUM>) in tubular anatomical structure (<NUM>). Stapling head assembly (<NUM>) is then urged distally to ensure that stapling head assembly (<NUM>) is fully seated at the distal end of tubular anatomical structure (<NUM>).

Next, anvil (<NUM>) is secured to trocar (<NUM>) by inserting trocar (<NUM>) into bore (<NUM>) as shown in <FIG>. Latch members (<NUM>) engage head (<NUM>) of trocar (<NUM>), thereby providing a secure fit between anvil (<NUM>) and trocar (<NUM>). The operator then rotates knob (<NUM>) while holding casing (<NUM>) stationary via pistol grip (<NUM>). This rotation of knob (<NUM>) causes trocar (<NUM>) and anvil (<NUM>) to retract proximally. As shown in <FIG>, this proximal retraction of trocar (<NUM>) and anvil (<NUM>) compresses the tissue of tubular anatomical structures (<NUM>, <NUM>) between surfaces (<NUM>, <NUM>) of anvil (<NUM>) and stapling head assembly (<NUM>). As this occurs, the operator may observe the tactile resistance or feedback via knob (<NUM>) while turning knob (<NUM>), with such tactile resistance or feedback indicating that the tissue is being compressed. As the tissue is being compressed, the operator may use user feedback feature (<NUM>) to determine whether the gap distance (d) between opposing surfaces (<NUM>, <NUM>) of anvil (<NUM>) and stapling head assembly (<NUM>) is appropriate; and make any necessary adjustments via knob (<NUM>).

Once the operator has appropriately set the gap distance (d) via knob (<NUM>), the operator actuates safety trigger (<NUM>) to enable actuation of firing trigger (<NUM>). The operator then actuates firing trigger (<NUM>). This actuates stapling head assembly (<NUM>) by driving knife member (<NUM>) and staple driver member (<NUM>) distally as shown in <FIG>. As knife member (<NUM>) translates distally, cutting edge (<NUM>) of knife member (<NUM>) cuts excess tissue that is positioned within annular recess (<NUM>) of anvil (<NUM>) and the interior of knife member (<NUM>).

As shown in <FIG>, anvil (<NUM>) of the present example includes a breakable washer (<NUM>) within annular recess (<NUM>). This washer (<NUM>) is broken by knife member (<NUM>) when the knife member (<NUM>) completes a full distal range of motion from the position shown in <FIG> to the position shown in <FIG>. The progressively increasing radius of curvature of second surface region may provide an increasing mechanical advantage as knife member (<NUM>) reaches the end of its distal movement, thereby providing greater force by which to break the washer (<NUM>). Of course, the breakable washer (<NUM>) may be omitted entirely in some versions. In versions where washer (<NUM>) is included, it should be understood that washer (<NUM>) may also serve as a cutting board for knife member (<NUM>) to assist in cutting of tissue.

As staple driver member (<NUM>) translates distally from the position shown in <FIG> to the position shown in <FIG>, staple driver member (<NUM>) drives staples (<NUM>) through the tissue of tubular anatomical structures (<NUM>, <NUM>) and into staple forming pockets (<NUM>) of anvil (<NUM>). Staple forming pockets (<NUM>) deform the driven staples (<NUM>) into a "B" shape as is known in the art; or into a three-dimensional shape. In either case, the formed staples (<NUM>) secure the ends of tissue together.

After the operator has actuated stapling head assembly (<NUM>) as shown in <FIG>, the operator rotates knob (<NUM>) to drive anvil (<NUM>) distally away from stapling head assembly (<NUM>), increasing the gap distance (d) to facilitate release of the tissue between surfaces (<NUM>, <NUM>). The operator then removes instrument (<NUM>) from the patient, with anvil (<NUM>) still secured to trocar (<NUM>). Referring back to the example where the tubular anatomical structures (<NUM>, <NUM>) comprise sections of a patient's colon, instrument (<NUM>) may be removed via the patient's rectum. With instrument (<NUM>) is removed, the tubular anatomical structures (<NUM>, <NUM>) are left secured together by two annular arrays of staples (<NUM>) at an anastomosis (<NUM>) as shown in <FIG>. The inner diameter of the anastomosis (<NUM>) is defined by the severed edge (<NUM>) left by knife member (<NUM>).

In some instances, knife members (<NUM>, <NUM>) may be manufactured using a blank, which may be a fully annealed steel blank. The blank may be deep drawn to form proximal flange (<NUM>, <NUM>) of knife member (<NUM>, <NUM>). This deep drawing process may limit the material selection of knife members (<NUM>, <NUM>) and/or may limit the range of manufacturing processes suitable for knife members (<NUM>, <NUM>). The material selection and/or manufacturing processes may impact the mechanical properties (e.g., hardness) of the knife members (<NUM>, <NUM>). For example, a softer material desirable for the deep drawing process may be cold-worked to obtain the desired hardness. The deep drawing process may cause cylindrical wall (<NUM>, <NUM>) to have slight variations in the thickness of the wall. Additionally, the heat staking process used to couple knife member (<NUM>, <NUM>) with staple driver member (<NUM>, <NUM>) may be process dependent.

For at least these reasons, it may be desirable to couple knife member (<NUM>, <NUM>) with staple driver member (<NUM>, <NUM>) in a manner that increases the range of suitable materials for knife member (<NUM>, <NUM>) to provide additional manufacturing freedom and/or provide a more uniform wall thickness of cylindrical wall (<NUM>, <NUM>) of knife members (<NUM>, <NUM>).

<FIG> show a second exemplary alternative knife member (<NUM>), a second exemplary alternative staple driver member (<NUM>), and an exemplary connector (<NUM>). Particularly, <FIG> shows a perspective view of knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) and <FIG> shows an exploded perspective view of knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>). Knife member (<NUM>) and staple driver member (<NUM>) of this example are configured and operable like knife member (<NUM>, <NUM>) and staple driver member (<NUM>, <NUM>), with differences described below. Connector (<NUM>) couples with both knife member (<NUM>) and staple driver member (<NUM>), and may provide an indirect coupling between knife member (<NUM>) and staple driver member (<NUM>).

Knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) may be incorporated into a modified version of instrument (<NUM>), which may include a body (shown as handle assembly (<NUM>)), a shaft (shown as shaft assembly (<NUM>)), and an anvil (shown as anvil (<NUM>)). For example, knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) may be insertable into stapling head assembly (<NUM>) in place of knife member (<NUM>) and staple driver member (<NUM>). Stapling head assembly (<NUM>) may be operable to drive at least one annular array of staples (<NUM>) though tissue and may include knife member (<NUM>), staple driver member (<NUM>), connector (<NUM>), as well as inner body member (<NUM>), deck member (<NUM>), trocar (<NUM>), at least one annular array of staples (<NUM>). Stapling head assembly (<NUM>) defines a longitudinal axis (LA). Stapling head assembly (<NUM>) includes an anvil coupling feature (e.g., trocar (<NUM>)). Anvil (<NUM>) is configured to couple with trocar (<NUM>) and deform at least one annular array of staples (<NUM>) driven by staple driver member (<NUM>).

<FIG> show knife member (<NUM>). Particularly, <FIG> shows a perspective view of knife member (<NUM>) of <FIG>, and <FIG> shows a top plan view of knife member (<NUM>) of <FIG>. Knife member (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a cylindrical body (<NUM>) extending between proximal and distal ends (<NUM>, <NUM>). Distal end (<NUM>) of knife member (<NUM>) includes a circular cutting edge (<NUM>) configured to cut through tissue. Cylindrical body (<NUM>) defines inner and outer surfaces (<NUM>, <NUM>) of knife member (<NUM>). Cylindrical body (<NUM>) extends along longitudinal axis (LA) of stapling head assembly (<NUM>). Cylindrical body (<NUM>) includes at least one coupling feature (shown as apertures (<NUM>)) that operatively couples knife member (<NUM>) with staple driver member (<NUM>). While the coupling features are shown as apertures (<NUM>), a variety of suitable coupling features are also envisioned. Additionally, while four individual radially spaced coupling features are shown, more or fewer coupler features are also envisioned, which may have the same or different spacing along knife member (<NUM>). While apertures (<NUM>) are shown as rectangular apertures that extend completely through cylindrical body (<NUM>), apertures (<NUM>) may have a variety of suitable shapes and sizes and may the same or different from one another. As shown in <FIG>, apertures (<NUM>) have a width (W).

As shown in <FIG>, cylindrical body (<NUM>) of knife member (<NUM>) defines a central cavity (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). Similar to knife member (<NUM>, <NUM>), knife member (<NUM>) may be coaxially positioned within staple driver member (<NUM>). As shown, cylindrical body (<NUM>) has a generally uniform thickness (t) disposed between inner and outer surfaces (<NUM>, <NUM>). Inner surface (<NUM>) defines an inner diameter (ID) of knife member (<NUM>), and outer surface (<NUM>) defines an outer diameter (OD) of knife member (<NUM>). Unlike knife member (<NUM>, <NUM>), proximal end (<NUM>) of knife member (<NUM>) does not include a radially inward extending proximal flange (similar to proximal flange (<NUM>, <NUM>)). As such, knife member (<NUM>) is not shown as including annular array of openings (<NUM>, <NUM>) disposed in proximal flanges (<NUM>, <NUM>). Knife member (<NUM>) may be formed from a metallic material. Knife member (<NUM>) is sized such that outer diameter (OD) of knife member (<NUM>) is smaller than the diameter defined by the inner annular array of staple drivers (<NUM>) of staple driver member (<NUM>) described below. Central cavity (<NUM>) of knife member (<NUM>) is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)).

<FIG> show connector (<NUM>). Particularly, <FIG> shows a perspective view of connector (<NUM>) of <FIG>, and <FIG> shows a top plan view of connector (<NUM>) of <FIG>. As will be discussed in greater detail below with reference to <FIG>, connector (<NUM>) is configured to couple knife member (<NUM>) with staple driver member (<NUM>). For example, connector (<NUM>) may be directly coupled with both knife member (<NUM>) and staple driver member (<NUM>). As shown in <FIG>, connector (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a body (<NUM>) disposed therebetween. Proximal end (<NUM>) of connector (<NUM>) includes a planar proximal surface (<NUM>) (see <FIG>).

Body (<NUM>) of connector (<NUM>) includes a base (<NUM>) and a plurality of arms (<NUM>) that extend distally from base (<NUM>). Body (<NUM>) defines inner and outer surfaces (<NUM>, <NUM>). Base (<NUM>) of connector (<NUM>) may include an inwardly extending flange (<NUM>). Inwardly extending flange (<NUM>) may increase the surface area that contacts staple driver member (<NUM>) which may provide for a more robust or stronger coupling. Connector (<NUM>) may be formed from a polymeric material. Arms (<NUM>) may be flexible, such that one or more arms (<NUM>) may deflect radially inwardly to couple with knife member (<NUM>). Arms (<NUM>) may be separated by a plurality of slots (<NUM>).

Connector (<NUM>) includes at least one coupling feature (shown as projections (<NUM>)) that is lockingly engaged with at least one coupling feature of cylindrical body (<NUM>) of knife member (<NUM>). While the coupling features of connector (<NUM>) are shown as projections (<NUM>), a variety of suitable coupling features are also envisioned. Additionally, while four individual radially spaced coupling features are shown in <FIG>, more or fewer coupling features are also envisioned having the same or different spacing. Projections (<NUM>) are shown as having a width (W) corresponding to the width (W) of apertures (<NUM>) of knife member (<NUM>). Projections (<NUM>) may extend radially outwardly from arms (<NUM>). Projections (<NUM>) extend from an outer surface (<NUM>) of body (<NUM>). Projections (<NUM>) are configured to lockingly engage with apertures (<NUM>) of cylindrical body (<NUM>) of knife member (<NUM>). While projections (<NUM>) are shown as outwardly facing rounded projections, projections (<NUM>) may have a variety of suitable shapes and sizes and may the same or different from one another. Projections (<NUM>) may be integrally formed as a unitary piece together with arms (<NUM>).

<FIG> show staple driver member (<NUM>). Particularly, <FIG> shows a perspective view of staple driver member (<NUM>) of <FIG>, and <FIG> shows a top plan view of staple driver member (<NUM>) of <FIG>. Similar to staple driver members (<NUM>, <NUM>), staple driver member (<NUM>) is operable to actuate longitudinally within a body member (e.g., body member (<NUM>)) in response to activation of the motor. Staple driver member (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a body (<NUM>) disposed therebetween. Body (<NUM>) includes two distally presented concentric annular arrays of staple drivers (<NUM>). Staple drivers (<NUM>) are arranged to correspond with the arrangement of staple forming pockets (similar to staple forming pockets (<NUM>)) described above. Thus, each staple driver (<NUM>) is configured to drive a corresponding staple into a corresponding staple forming pocket (<NUM>) of anvil (<NUM>) when stapling head assembly (<NUM>) is actuated.

It should be understood that the arrangement of staple drivers (<NUM>) may be modified just like the arrangement of staple forming pockets (<NUM>) as described above. Staple driver member (<NUM>) includes an inner surface (<NUM>) that defines a bore (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). As shown in <FIG>, inner surface (<NUM>) may be generally circular. Unlike staple driver member (<NUM>, <NUM>), staple driver member (<NUM>) is not shown as including an annular array of studs (e.g., annular array of studs (<NUM>, <NUM>)) that project distally from a distally presented surface (shown as a planar surface (<NUM>) in <FIG>) that surrounds bore (<NUM>).

Knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) may be driven distally as similarly shown in <FIG> regarding stapling head assembly (<NUM>). As knife member (<NUM>) translates distally, cutting edge (<NUM>) of knife member (<NUM>) cuts excess tissue that is positioned within an annular recess (e.g., annular recess (<NUM>) of anvil (<NUM>)) and the interior of knife member (<NUM>). The inner diameter of the anastomosis is defined by the severed edge left by knife member (<NUM>). Other suitable structural relationships between knife member (<NUM>) and staple driver member (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

A method of manufacturing is also described with reference to <FIG>. <FIG> shows a cross-sectional side view of knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) of <FIG> prior to coupling the components together. <FIG> shows a cross-sectional side view of knife member (<NUM>), staple driver member (<NUM>), and connector (<NUM>) of <FIG> after the components are coupled together.

To form knife member (<NUM>), a long hollow tube may be cut to the desired length to produce a blank. Once the blank is formed, the blank may be centerless ground so that the blank has a uniform wall thickness. As such, knife member (<NUM>) may have greater concentricity between the inner diameter (ID) and the outer diameter (OD) relative to knife members (<NUM>, <NUM>). The outer diameter (OD) of knife member (<NUM>) may be identical or similar to knife members (<NUM>, <NUM>). Additionally, knife member (<NUM>) may have greater hardness, and/or be more suitable to one or more grinding processes, which is less likely to create burrs in comparison to an exemplary material (e.g., SS <NUM>) used to form knife members (<NUM>, <NUM>). SS <NUM> is an austenitic chromium-nickel stainless steel with corrosion resistance, and is suitable for severe cold forming operations. SS <NUM> may be better suited to deep drawing, which may be used to produce knife members (<NUM>, <NUM>) as opposed to grinding operations, which may be used to form knife member (<NUM>). As described above, knife member (<NUM>, <NUM>) may be formed from a metallic material. For example, knife member (<NUM>, <NUM>) may be formed from a variety of steel alloys including, but not limited to, SS <NUM> and SS <NUM>. SS <NUM> is an austenitic stainless steel that may allow for extensive machining operations, where the addition of sulfur may assist in breaking up turnings while reducing drag on the cutting tool. SS <NUM> is an austenitic stainless steel that may contain a nickel content of between approximately <NUM> and <NUM> percent by weight and a chromium content of between approximately <NUM> to <NUM> percent by weight. The high amounts of chromium and nickel may provide SS <NUM> with corrosion resistance.

It is envisioned that knife member (<NUM>) may be coupled together with connector (<NUM>) prior to or after connector (<NUM>) is coupled with staple driver member (<NUM>). For example, the method may include welding connector (<NUM>) with staple driver member (<NUM>) before or after knife member (<NUM>) is mechanically coupled with connector (<NUM>). Particularly, connector (<NUM>) may be welded to staple driver member (<NUM>), and then knife member (<NUM>) may be inserted between an inner surface (<NUM>) of staple driver member (<NUM>) and outer surface (<NUM>) of connector (<NUM>) and subsequently fixably coupled with connector (<NUM>) as described below. Alternatively, knife member (<NUM>) may be mechanically coupled with connector (<NUM>) by coupling projections (<NUM>) in apertures ((<NUM>), and then connector (<NUM>) is inserted into staple driver member (<NUM>) and fixably coupled together. As shown, planar proximal surface (<NUM>) of connector (<NUM>) may be fixably coupled together with planar surface (<NUM>) of staple driver member (<NUM>) using at least one welding process. For example, the welding process may include harmonic welding (i.e., sonic welding). However, it is also envisioned that connector (<NUM>) may be fixably coupled together with staple driver member (<NUM>) using a variety of other suitable methods (e.g., over molding).

Regarding the coupling of knife member (<NUM>) with connector (<NUM>), respective coupling features of knife member (<NUM>) and connector (<NUM>) fixably secure knife member (<NUM>) directly with connector (<NUM>). For example, at least one coupling feature (e.g., apertures (<NUM>)) of cylindrical body (<NUM>) of knife member (<NUM>) may couple with at least one corresponding coupling feature (e.g., projections (<NUM>)) of connector (<NUM>) to operatively couple knife member (<NUM>) with staple driver member (<NUM>). Connector (<NUM>) may be coaxially disposed within central cavity (<NUM>) of cylindrical body (<NUM>) of knife member (<NUM>).

Regarding the coupling of knife member (<NUM>) with connector (<NUM>), arms (<NUM>) of connector (<NUM>) may be flexible, such that one or more arms (<NUM>) of connector (<NUM>) may deflect radially inwardly. As shown, projections (<NUM>) of connector (<NUM>) deflect radially inwardly as knife member (<NUM>) translates relative to connector (<NUM>). To fixably secure connector (<NUM>) and staple driver member (<NUM>) together, projections (<NUM>) of connector (<NUM>) deflect back radially outwardly into corresponding apertures (<NUM>) of knife member (<NUM>). This snaps projections (<NUM>) of connector (<NUM>) into corresponding apertures (<NUM>) of knife member (<NUM>). As shown in <FIG>, knife member (<NUM>) is indirectly coupled (i.e., not directly coupled) with staple driver member (<NUM>). However, it is also envisioned that knife member (<NUM>) may be directly coupled with staple driver member (<NUM>) as will be described below with reference to <FIG>.

Various benefits may be obtained this this coupling method, including one or more of increased sharpness of cutting edge (<NUM>) of knife member (<NUM>), a generally uniform tip radius of cutting edge (<NUM>) of knife member (<NUM>), increased hardness of knife member (<NUM>), and/or reduced variation in the height of knife member (<NUM>). Reduced variation in the height of knife member (<NUM>) may allow for a more uniform cutting force on breakable washer (<NUM>) and/or simply the manufacturing process.

<FIG> show a third exemplary alternative knife member (<NUM>) and a third exemplary alternative staple driver member (<NUM>). <FIG> shows a cross-sectional side view of knife member (<NUM>), staple driver member (<NUM>) prior to coupling the components together. <FIG> shows a cross-sectional side view of knife member (<NUM>), staple driver member (<NUM>) after being coupled together. The knife member (<NUM>) directly couples with staple driver member (<NUM>).

Knife member (<NUM>) and staple driver member (<NUM>) of this example are configured and operable like knife member (<NUM>) and staple driver member (<NUM>), with differences described below. Similar knife member (<NUM>) and staple driver member (<NUM>), knife member (<NUM>) and staple driver member (<NUM>) may be incorporated into a modified version of instrument (<NUM>), which may include a body (shown as handle assembly (<NUM>)), a shaft (shown as shaft assembly (<NUM>)), and an anvil (shown as anvil (<NUM>)). For example, knife member (<NUM>) and staple driver member (<NUM>) may be insertable into stapling head assembly (<NUM>) in place of knife member (<NUM>) and staple driver member (<NUM>).

Knife member (<NUM>) is similar to knife member (<NUM>) shown and described above with reference to <FIG> and <FIG>. Knife member (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a cylindrical body (<NUM>) extending between proximal and distal ends (<NUM>, <NUM>). Distal end (<NUM>) of knife member (<NUM>) includes a circular cutting edge (<NUM>) configured to cut through tissue. Cylindrical body (<NUM>) defines inner and outer surfaces (<NUM>, <NUM>) of knife member (<NUM>). Cylindrical body (<NUM>) extends along longitudinal axis (LA) of stapling head assembly (<NUM>). Cylindrical body (<NUM>) includes at least one coupling feature (shown as apertures (<NUM>) which may be similar to apertures (<NUM>)) that fixably couples knife member (<NUM>) with staple driver member (<NUM>). While the coupling features are shown as apertures (<NUM>), a variety of suitable coupling features are also envisioned. Similar to apertures (<NUM>), the number and spacing of apertures (<NUM>) may vary. While apertures (<NUM>) are shown as rectangular apertures that extend completely through cylindrical body (<NUM>), apertures (<NUM>) may have a variety of suitable shapes and sizes and may the same or different from one another.

As shown, cylindrical body (<NUM>) of knife member (<NUM>) defines a central cavity (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). Knife member (<NUM>) may be coaxially positioned within staple driver member (<NUM>). Unlike knife member (<NUM>, <NUM>), proximal end (<NUM>) of knife member (<NUM>) does not include a radially inward extending proximal flange (similar to proximal flange (<NUM>, <NUM>)). As such, knife member (<NUM>) is not shown as including annular array of openings (<NUM>, <NUM>) disposed in proximal flanges (<NUM>, <NUM>). Knife member (<NUM>) may be formed from a metallic material. Knife member (<NUM>) is sized such that the outer diameter of knife member (<NUM>) is smaller than the diameter defined by the inner annular array of staple drivers (<NUM>) of staple driver member (<NUM>) described below. Central cavity (<NUM>) of knife member (<NUM>) is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)).

Staple driver member (<NUM>) is similar to staple driver member (<NUM>), which is shown and described above with reference to <FIG>. Similar to staple driver members (<NUM>, <NUM>, <NUM>), staple driver member (<NUM>) is operable to actuate longitudinally within a body member (e.g., body member (<NUM>)) in response to activation of the motor. Staple driver member (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a body (<NUM>) disposed therebetween. Body (<NUM>) includes two distally presented concentric annular arrays of staple drivers (<NUM>). Staple drivers (<NUM>) are arranged to correspond with the arrangement of staple forming pockets (similar to staple forming pockets (<NUM>)) described above. Staple driver member (<NUM>) includes an inner surface (<NUM>) that defines a bore (<NUM>) that is configured to coaxially receive an inner core member (e.g., inner core member (<NUM>) of body member (<NUM>)). Unlike staple driver member (<NUM>, <NUM>) but similar to staple driver member (<NUM>), staple driver member (<NUM>) is not shown as including an annular array of studs (e.g., annular array of studs (<NUM>, <NUM>)) that project distally from a distally presented surface (shown as a planar surface (<NUM>) in <FIG>) that surrounds bore (<NUM>).

Unlike staple driver member (<NUM>), staple driver member (<NUM>) includes at least one coupling feature (shown as projections (<NUM>)) that is lockingly engaged with at least one coupling feature of cylindrical body (<NUM>) of knife member (<NUM>). While the coupling features of staple driver member (<NUM>) are shown as projections (<NUM>), a variety of suitable coupling features are also envisioned. Similar to projections (<NUM>), the number and spacing of projections (<NUM>) may vary. Projections (<NUM>) are configured to lockingly engage with apertures (<NUM>) of cylindrical body (<NUM>) of knife member (<NUM>). While projections (<NUM>) are shown as inwardly facing rounded projections, projections (<NUM>) may have a variety of suitable shapes and sizes and may the same or different from one another. Staple driver member (<NUM>) may be formed from a polymeric material. Projections (<NUM>) may be integrally formed as a unitary piece together with inner surface (<NUM>).

Knife member (<NUM>) and staple driver member (<NUM>) may be driven distally as similarly shown in <FIG> regarding stapling head assembly (<NUM>). As knife member (<NUM>) translates distally, cutting edge (<NUM>) of knife member (<NUM>) cuts excess tissue that is positioned within an annular recess (e.g., annular recess (<NUM>) of anvil (<NUM>)) and the interior of knife member (<NUM>). Other suitable structural relationships between knife member (<NUM>) and staple driver member (<NUM>) will be apparent to those of ordinary skill in the art in view of the teachings herein.

A method of manufacturing is also described with reference to <FIG>. The respective coupling features of knife member (<NUM>) and staple driver member (<NUM>) may fixably secure knife member (<NUM>) directly with staple driver member (<NUM>). For example, at least one coupling feature (e.g., apertures (<NUM>)) of cylindrical body (<NUM>) of knife member (<NUM>) may couple with at least one corresponding coupling feature (e.g., projections (<NUM>)) of staple driver member (<NUM>) to couple knife member (<NUM>) with staple driver member (<NUM>).

Inner surface (<NUM>) of staple driver member (<NUM>) may be flexible, such that projections (<NUM>) of staple driver member (<NUM>) deflect radially outwardly as knife member (<NUM>) translates relative to staple driver member (<NUM>). To fixably secure knife member (<NUM>) and staple driver member (<NUM>) together, projections (<NUM>) of staple driver member (<NUM>) deflect back radially inwardly into corresponding apertures (<NUM>) of knife member (<NUM>). Unlike projections (<NUM>) which are outwardly facing, projections (<NUM>) are shown as being inwardly facing. This snaps projections (<NUM>) of staple driver member (<NUM>) into corresponding apertures (<NUM>) of knife member (<NUM>). As shown, there is no coupling between proximal end (<NUM>) of knife member (<NUM>) and planar surface (<NUM>) of staple driver member (<NUM>). However, it is envisioned, that planar surface (<NUM>) may be coupled with proximal end (<NUM>) in addition to the coupling provided by projections (<NUM>) of staple driver member (<NUM>) and apertures (<NUM>) of knife member (<NUM>).

It should also be understood that any one or more of the teachings, expressions, examples, etc. described herein may be combined with any one or more of the other teachings, expressions, examples, etc. that are described herein. The above-described teachings, expressions, examples, etc. should therefore not be viewed in isolation relative to each other.

At least some of the teachings herein may also be readily combined with one or more teachings of <CIT>; <CIT>, now abandoned; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>. Various suitable ways in which the teachings herein may be combined with the teachings of the above-referenced patents, publications, and patent applications will be apparent to those of ordinary skill in the art.

While the examples herein have been provided in the context of a circular stapling instrument, it should be understood that the various teachings herein may be readily applied to various other kinds of surgical instruments. By way of example only, the various teachings herein may be readily applied to linear stapling devices (e.g., endocutters). As another merely illustrative example, the various teachings herein may be readily applied to a motorized electrosurgical device. For instance, various teachings herein may be readily combined with various teachings of <CIT>, as will be apparent to those of ordinary skill in the art. Other suitable kinds of instruments in which the teachings herein may be applied, and various ways in which the teachings herein may be applied to such instruments, will be apparent to those of ordinary skill in the art.

Versions described above may be designed to be disposed of after a single use, or they can be designed to be used multiple times.

Claim 1:
An apparatus comprising:
(a) a body;
(b) a shaft extending distally from the body; and
(c) a stapling head assembly positioned at a distal end of the shaft, wherein the stapling head assembly comprises:
(i) a staple driver member (<NUM>) configured to drive a plurality of staples into tissue, and
(ii) a knife member (<NUM>) configured to cut through the tissue, wherein the knife member comprises:
(A) a proximal end (<NUM>),
(B) a distal end (<NUM>), and
(C) a cylindrical body (<NUM>) extending between the proximal and distal ends, wherein the cylindrical body includes at least one coupling feature (<NUM>) that operatively couples the knife member with the staple driver member,
wherein the stapling head assembly further comprises a connector (<NUM>) that couples the knife member with the staple driver member, and wherein the connector (<NUM>) includes a proximal end (<NUM>), a distal end (<NUM>), and a body (<NUM>) disposed therebetween, wherein the proximal end of the connector includes a flat surface, wherein the staple driver member includes a flat surface,
characterized in that the flat surfaces of the connector and the staple driver member are fixably coupled together.