Patent Description:
Conventional manually operated circular stapling devices include an elongate body, a shell assembly that is supported on a distal portion of the elongate body, and an anvil assembly that is movably supported on the distal portion of the elongate body adjacent to the shell assembly. The shell assembly includes a shell housing, a staple cartridge supported on the shell housing, a pusher assembly, and a knife supported on the pusher assembly. The staple cartridge supports a plurality of staples. The pusher assembly includes a staple pushing member that is movable through the staple cartridge to eject the plurality of staples from the staple cartridge through tissue and form the staples against the anvil assembly. The knife is coupled to and movable with the staple pushing member to dissect the tissue clamped between the shell assembly and the anvil assembly during staple formation.

<CIT> describes a circular stapling instrument including a stapling forming assembly that is actuated independently from actuation of the cutting assembly. 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. The cartridge assembly includes a pusher assembly and a knife assembly. The knife assembly is selectively fixed relative to the pusher assembly.

<CIT> shows a surgical instrument which comprises a tissue clamping system, a staple firing system, and a tissue cutting system. The systems of the surgical instrument can co-operate with one another to prevent the systems from being operated out of order, and/or prevent the systems from being operated in an undesirable order.

The invention is disclosed in the independent claims.

One aspect of the disclosure is directed to a circular stapling device including a handle assembly, an elongate body, and a shell assembly. The handle assembly includes a firing trigger. The elongate body is supported by the handle assembly and includes a proximal portion and a distal portion. The shell assembly is supported on the distal portion of the elongate body and includes a shell housing defining a cavity, a staple cartridge, a pusher defining a longitudinal bore, a knife carrier, and a knife. The staple cartridge is supported on the shell housing and supports a plurality of staples. The knife carrier is movable within the longitudinal bore of the pusher and the knife is supported on the knife carrier. The pusher is movable within the cavity of the shell housing from a retracted position to an advanced position to eject the plurality of staples from the staple cartridge. The anvil assembly is supported on the distal portion of the elongate body and is movable in relation to the shell assembly between open and clamped positions. The knife carrier is adapted to releasably engage the pusher and is movable between a retracted position and an intermediate position to move the pusher from its retracted position to its advanced position and subsequently movable from its intermediate position to an advanced position independently of the pusher to advance the knife to cut tissue.

In embodiments, the firing trigger is coupled to the knife carrier such that movement of the firing trigger through an actuation stroke moves the knife carrier from its retracted position to its advanced position.

In some embodiments, the firing trigger is manually movable through the actuation stroke.

In certain embodiments, the knife carrier includes at least one tab that is movable from a first position engaged with the pusher to translate distal movement of the knife carrier to distal movement of the pusher to a second position to allow distal advancement of the knife carrier independently of the pusher.

In embodiments, each of the at least one tabs is supported on a resilient arm.

In some embodiments, the resilient arm supporting each of the at least one tabs is supported in cantilevered fashion to the knife carrier.

In certain embodiments, the shell assembly includes a housing that includes at least one longitudinal rib that is positioned to engage the resilient arm supporting each of the at least one tabs to retain each of the at least one tabs in the first position as the pusher is moved towards its advanced position.

In embodiments, one of the pusher and the knife carrier includes a breakable ring and the other of the pusher and the knife carrier includes an annular projection that is positioned to engage the breakable ring.

In some embodiments, the breakable ring is adapted to fracture when the pusher nears its advanced position to facilitate movement of the knife carrier independently of the pusher.

Another aspect of the disclosure is directed to a shell assembly including a shell housing defining a cavity, a staple cartridge, a pusher defining a longitudinal bore, a knife carrier, and a knife. The staple cartridge is supported on the shell housing and supports a plurality of staples. The knife carrier is movable within the longitudinal bore of the pusher and the knife is supported on the knife carrier. The pusher is movable within the cavity of the shell housing from a retracted position to an advanced position to eject the plurality of staples from the staple cartridge. The knife carrier is adapted to engage the pusher and is movable between a retracted position and an intermediate position to move the pusher from its retracted position to its advanced position and subsequently movable from its intermediate position to an advanced position independently of the pusher to advance the knife to cut tissue.

Another aspect of the disclosure is directed to a shell assembly including a shell housing defining a cavity, a staple cartridge, a pusher defining a longitudinal bore, a knife carrier, and a knife. The staple cartridge is supported on the shell housing and supports a plurality of staples. The pusher defines a longitudinal bore and is movable within the cavity of the shell housing from a retracted position to an advanced position to eject the plurality of staples from the staple cartridge. The knife carrier is movable within the longitudinal bore of the pusher and supports the knife, wherein the knife carrier is releasably coupled to the pusher and movable independently of the pusher to cut tissue after staple formation.

Various embodiments of the disclosed stapling device are described herein below with reference to the drawings, wherein:.

The disclosed stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

In this description, the term "proximal" is used generally to refer to that portion of the device that is closer to a clinician, while the term "distal" is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term "clinician" is used generally to refer to medical personnel including doctors, nurses, and support personnel.

The disclosed circular stapling device is a manually operated stapling device that includes a manually operated trigger that is adapted to allow staple formation to occur prior to cutting of tissue during a single actuation of the firing trigger. The stapling device minimizes stretching and movement of tissue during staple formation to improve staple formation. The stapling device also reduces the amount of force required to move the firing trigger through a firing stroke by separating the staple formation and tissue cutting functions of the stapling device to reduce stress on a clinician's hand during actuation of the stapling device.

<FIG> illustrates an exemplary embodiment of the disclosed circular stapling device shown generally as stapling device <NUM>. The stapling device <NUM> includes a handle assembly <NUM>, an elongate body <NUM>, a shell assembly <NUM>, and an anvil assembly <NUM> that is supported for movement in relation to the shell assembly <NUM> between spaced and approximated positions as described below. The anvil assembly <NUM> has an anvil shaft <NUM> that is adapted to be releasably coupled to an approximation mechanism (not shown) of the stapling device <NUM> as is known in the art. The elongate body <NUM> has a distal portion 14a and a proximal portion 14b. In embodiments, the shell assembly <NUM> includes a proximal portion <NUM> that is releasably coupled to the distal portion 14a of the elongate body <NUM>. Alternately, the shell assembly <NUM> can be fixedly secured to the elongate body portion <NUM>.

The handle assembly <NUM> includes a stationary grip <NUM> that supports a firing trigger <NUM> and an approximation knob <NUM>. The approximation knob <NUM> is actuable to move the anvil assembly <NUM> in relation to the shell assembly <NUM> between open and clamped positions. The firing trigger <NUM> is movable through an actuation stroke to control operation of various functions of the stapling device <NUM> including firing of staples from the shell assembly <NUM> and cutting or coring of tissue.

<FIG> illustrates the shell assembly <NUM> of the stapling device <NUM> shown in <FIG>. The shell assembly <NUM> includes a shell housing <NUM>, a pusher <NUM>, a knife carrier <NUM>, an annular knife <NUM> supported on the knife carrier <NUM>, a staple cartridge <NUM>, and a plurality of staples <NUM> supported within the staple cartridge <NUM>. The staple cartridge <NUM> is annular and defines annular rows of staple pockets <NUM>. Each of the staple pockets <NUM> supports one of the plurality of staples <NUM>. The pusher <NUM> includes a body <NUM> that defines a longitudinal bore 44a and includes a distal portion having a plurality of fingers <NUM>. Each of the plurality of fingers <NUM> is received within and movable through a respective one of the staple pockets <NUM> of the staple cartridge <NUM> to eject the staples <NUM> from the staple pockets <NUM> when the pusher <NUM> is moved within the shell housing <NUM> from a retracted position to an advanced position.

<FIG> illustrates the shell housing <NUM> of the shell assembly <NUM>. The shell housing <NUM> includes an outer housing portion <NUM> and an inner housing portion <NUM> that are spaced from each other to define an annular cavity <NUM>. The inner housing portion <NUM> of the shell housing <NUM> defines a through bore <NUM> that receives the anvil shaft <NUM> (<FIG>) of the anvil assembly <NUM> when the anvil assembly <NUM> is moved to the clamped position to align the anvil assembly <NUM> with the staple cartridge <NUM> of the shell assembly <NUM>. The inner housing portion <NUM> includes an outer surface supporting longitudinal ribs <NUM> that are positioned within the annular cavity <NUM> of the shell housing <NUM>. The shell housing <NUM> also includes struts <NUM> that extend between the inner housing portion <NUM> and the outer housing portion <NUM>. The struts <NUM> confine the knife carrier <NUM> to longitudinal movement within the shell housing <NUM> as described in detail below.

The knife carrier <NUM> is received within the annular cavity <NUM> of the shell housing <NUM> and within the pusher <NUM> and includes an annular body <NUM>. The annular body <NUM> defines a longitudinal through bore 60a and has a distal portion <NUM> and a proximal portion <NUM>. In embodiments, the distal portion <NUM> defines an annular recess <NUM> that receives the proximal end of the annular knife <NUM> to secure the knife <NUM> to the knife carrier <NUM>. The knife <NUM> may also have tabs <NUM> (<FIG>) that engage the knife carrier <NUM> to further secure the knife <NUM> to the knife carrier <NUM>. Alternately other securement techniques can be used to secure the knife <NUM> to the knife carrier <NUM>.

The proximal portion <NUM> of the annular body <NUM> of the knife carrier <NUM> is defined by spaced legs <NUM> that are separated by longitudinal slots <NUM>. When the knife carrier <NUM> is received in the annular cavity <NUM> of the shell housing <NUM>, the longitudinal slots <NUM> receive the struts <NUM> of the shell housing <NUM> to confine the knife carrier <NUM> to longitudinal movement within the shell housing <NUM>. A proximal portion of the annular body <NUM> of the knife carrier <NUM> supports coupling members <NUM>. The coupling members <NUM> are adapted to engage a drive member (not shown) supported within the elongate body <NUM> to couple the knife carrier <NUM> to the firing trigger (<FIG>).

<FIG> illustrates the distal portion of the knife carrier <NUM> with the knife carrier received within longitudinal bore 44a of the pusher <NUM>. As illustrated, the annular body <NUM> of the knife carrier <NUM> supports one or more resilient cantilevered arms <NUM>. In embodiments, each of the arms <NUM> has a distal end supported by the annular body <NUM> and a proximal end that supports a tab <NUM>. The tabs <NUM> extend radially outward from the arms <NUM> and are positioned to engage a proximal portion of the pusher <NUM> such that movement of the knife carrier <NUM> effects distal movement of the pusher <NUM> within the annular cavity <NUM> of the shell housing <NUM> between a retracted position and an advanced position as described in further detail below. The cantilevered arms <NUM> of the knife carrier <NUM> are resilient and can flex inwardly into the longitudinal through bore 60a of the knife carrier <NUM> when the pusher <NUM> has reached its advanced position to allow the knife carrier <NUM> to move distally independently of the pusher <NUM> after staple formation to cut tissue. The tabs <NUM> may be positioned to engage the proximal end of the pusher <NUM>. Alternately, other configurations are envisioned. As shown in <FIG>, the proximal portion of the pusher <NUM> may include elongated slots or notches <NUM>. The notches <NUM> receive the struts <NUM> (<FIG>) of the shell housing <NUM> to properly align the pusher <NUM> within the shell housing <NUM>.

<FIG> illustrate the distal portion of the stapling device <NUM> with the anvil assembly <NUM> in the clamped position about tissue "T" prior to actuation of the firing trigger <NUM> (<FIG>). In this position, the knife carrier <NUM> and the pusher <NUM> are in their retracted positions within the shell housing <NUM>. The cantilevered arms <NUM> of the knife carrier <NUM> are supported on the longitudinal ribs <NUM> of the inner housing portion <NUM> of the shell housing <NUM>. When the cantilevered arms <NUM> are supported on the longitudinal ribs <NUM>, the arms <NUM> are deformed outwardly from the knife carrier <NUM> to urge the tabs <NUM> outwardly into longitudinal alignment and/or engagement with the pusher <NUM>.

<FIG> illustrates the stapling device <NUM> with the anvil assembly <NUM> in the clamped position about the tissue "T" as the firing trigger <NUM> (<FIG>) is moved through an actuation stroke and the staples <NUM> are formed in the tissue "T". Initially, when the firing trigger <NUM> is actuated, the knife carrier <NUM> is advanced in the direction indicated by arrows "A". As the knife carrier <NUM> is advanced, the tabs <NUM> on the cantilevered arms <NUM> engage the pusher <NUM> to advance the pusher <NUM> with the knife carrier <NUM> in the direction indicated by arrows "B". As the pusher <NUM> moves distally within the shell housing <NUM>, the fingers <NUM> of the pusher <NUM> pass through the staple pockets <NUM> of the staple cartridge <NUM> to advance and form the staples <NUM> against the anvil assembly <NUM>. In this position, the knife <NUM> has yet to engage the tissue "T". Alternately, the knife <NUM> may be in contact with the tissue "T" as staple formation is completed.

As illustrated in <FIG>, when the knife carrier <NUM> advances in the direction indicated by arrows "A" to a position in which the cantilevered arms <NUM> of the knife carrier <NUM> pass off of distal ends of the longitudinal ribs <NUM> on the inner housing portion <NUM> of the shell housing <NUM>, the cantilevered arms <NUM> move inwardly due to the resilience of the arms <NUM> such that the tabs <NUM> disengage from the pusher <NUM>. When this occurs, the knife carrier <NUM> will advance or move distally independently of the pusher <NUM> to advance the knife <NUM> in the direction of arrows "C" to cut the tissue "T". The distal ends of the tabs <NUM> may include a chamfer to allow engagement between the tabs <NUM> and the pusher <NUM> to assist in moving the arms <NUM> inwardly to facilitate separation of the tabs <NUM> and the pusher <NUM>.

As discussed briefly above, separating the two functions of the stapling device <NUM>, i.e., staple formation and cutting, allows the forces required to actuate the firing trigger <NUM> of the stapling device <NUM> to be reduced and minimizes pulling or stretching of tissue during staple formation to improve staple formation.

<FIG> illustrate another exemplary embodiment of the disclosed stapling device <NUM> (<FIG>) which is similar to the embodiment described above with the exception of modifications to the pusher <NUM> and the knife carrier <NUM> which are described in further detail below.

The pusher <NUM> is substantially identical to the pusher <NUM> (<FIG>) except that the inner wall of the pusher <NUM> includes a frangible or breakable ring 132a (<FIG>) that projects into the longitudinal bore 144a of the pusher <NUM>. In addition, the knife carrier <NUM> is substantially similar to the knife carrier <NUM> except that the cantilevered arms <NUM> are eliminated and a projection, such as an annular ring <NUM> (<FIG>), is formed on the distal portion <NUM> of the knife carrier <NUM>.

<FIG> illustrates the distal portion of the stapling device <NUM> (<FIG>) with the anvil assembly <NUM> in the clamped position about tissue "T" prior to actuation of the firing trigger <NUM> (<FIG>). In this position, the knife carrier <NUM> and the pusher <NUM> are in their retracted positions within the shell housing <NUM>. The projection on the knife carrier <NUM>, e.g., annular ring <NUM>, is positioned immediately proximal to and in alignment with the breakable ring 132a of the pusher <NUM>. Although the annular ring <NUM> of the knife carrier <NUM> is shown engaged with the breakable ring 132a, the two components need only be aligned with each other prior to actuation of the firing trigger <NUM> (<FIG>).

<FIG> illustrate the stapling device <NUM> with the anvil assembly <NUM> in the clamped position about the tissue "T" as the firing trigger <NUM> (<FIG>) is moved through an actuation stroke. Initially, when the firing trigger <NUM> (<FIG>) is actuated the knife carrier <NUM> is advanced in the direction indicated by arrows "D". As the knife carrier <NUM> is advanced, the annular ring <NUM> on the knife carrier <NUM> engages the breakable ring 132a on the pusher <NUM> to advance the pusher <NUM> with the knife carrier <NUM> in the direction indicated by arrows "D". As the pusher <NUM> moves distally within the shell housing <NUM>, the fingers <NUM> of the pusher <NUM> passes through the staple pockets <NUM> of the staple cartridge <NUM> to advance and form the staples <NUM> against the anvil assembly <NUM>. In this position, the knife <NUM> has yet to engage the tissue "T". Alternately, the knife <NUM> may be in contact with the tissue "T" as staple formation is completed.

When the staple formation is completed, advancement of the pusher <NUM> is obstructed via engagement between the staple cartridge <NUM> and the pusher <NUM>. When this occurs, the force applied to the breakable ring 132a of the pusher <NUM> by the annular ring <NUM> of the knife carrier <NUM> increase beyond a threshold force and the breakable ring 132a is sheared from the inner wall of the pusher <NUM> to allow the knife carrier <NUM> to move distally independently of the pusher <NUM> in the direction indicate by arrows "E" to cut the tissue "T".

Claim 1:
A circular stapling device (<NUM>) comprising:
a handle assembly (<NUM>) including a firing trigger (<NUM>);
an elongate body (<NUM>) supported by the handle assembly, the elongate body having a proximal portion and a distal portion;
a shell assembly (<NUM>) supported on the distal portion of the elongate body, the shell assembly including a shell housing defining a cavity, a staple cartridge supported on the shell housing, a pusher (<NUM>) defining a longitudinal bore, a knife carrier (<NUM>) movable within the longitudinal bore, and a knife supported on the knife carrier, the staple cartridge supporting a plurality of staples and the pusher being movable within the cavity of the shell housing from a retracted position to an advanced position to eject the plurality of staples from the staple cartridge; and
an anvil assembly (<NUM>) supported on the distal portion of the elongate body and being movable in relation to the shell assembly between open and clamped positions;
wherein the knife carrier engages the pusher and is movable between a retracted position and an intermediate position to move the pusher from its retracted position to its advanced position and subsequently movable from its intermediate position to an advanced position independently of the pusher to advance the knife to cut tissue;
wherein the knife carrier includes at least one tab (<NUM>), the at least one tab being configured to be movable from a first position engaged with the pusher to translate distal movement of the knife carrier to distal movement of the pusher, to a second position to allow distal advancement of the knife carrier independently of the pusher; wherein each of the at least one tabs is supported on a resilient arm (<NUM>).