Patent Description:
The disclosure is directed to circular stapling devices and, more particularly, to reload assemblies for circular stapling devices with structure to retain a knife carrier of the reload assembly in a retracted position after the stapling device is fired.

Conventional circular stapling devices include an elongate body and a shell or reload assembly that is supported on a distal portion of the elongate body. The reload assembly includes a shell housing, a staple cartridge having a plurality of staples supported on the shell housing, a pusher assembly, a knife defining a cylindrical cavity, and a knife carrier that supports the knife. The pusher assembly includes an annular pusher and a staple pushing member that is engaged with the annular pusher and is movable to move the staple pushing member to eject staples from the staple cartridge. The knife carrier is movable to advance the knife through the staple cartridge to core or cut tissue.

After a stapling device has been operated to staple and cut tissue, the knife carrier and the knife are retracted to withdraw the knife into the shell housing. This serves two purposes. The first purpose is to move the knife to a position to allow removal of a tissue donut from within the cavity defined by the knife. The second purpose is to position the knife in a location recessed within the shell housing to avoid injury to a clinician during manipulation and disposal of the reload assembly.

In some instances, the tissue donut is compressed within the cavity defined by the knife to such a degree that removal of the tissue donut from within the cavity defined by the knife is difficult. A continuing need exists in the art for a reload assembly that includes improved structure for retaining the knife/knife carrier in a retracted position.

<CIT> relates to a circular stapler comprising a handle assembly, an elongate body, and a cartridge assembly. The cartridge assembly includes a pusher assembly and a knife assembly which are coupled via a latch assembly.

<CIT> forms prior art according to Art. <NUM>(<NUM>) EPC and relates to reload assemblies for circular stapling devices with structure to retain a knife carrier in a retracted position prior to and after firing of the stapling device.

One aspect of the disclosure is directed to a surgical stapling device including an adaptor assembly and a reload assembly. The adaptor assembly has a proximal end portion and a distal end portion. The reload assembly is supported on the distal end portion of the adaptor assembly and includes a shell housing, a staple pusher, a staple actuator, a knife carrier, and a knife supported on the knife carrier. The shell housing includes an outer housing portion and an inner housing portion that together define an annular cavity. The staple cartridge supports a plurality of staples. The staple pusher is supported within the annular cavity and is movable from a retracted position to an advanced position to eject staples from the staple cartridge. The staple actuator is supported within the annular cavity and has a stop surface. The staple actuator is engaged with the staple pusher and is movable from a retracted position to an advanced position to move the staple pusher from its retracted position to its advanced position. The staple actuator and the staple pusher define a through bore. The knife carrier is supported within the through bore and is movable between a retracted position and an advanced position. The knife carrier supports a resilient locking member that is aligned with the stop surface on the staple actuator when the staple actuator is in its advanced position and the knife carrier is in its retracted position to prevent readvancement of the knife carrier.

In embodiments, the stapling device includes a handle assembly, wherein the proximal end portion of the adaptor assembly is supported on the handle assembly.

In some embodiments, the locking member is movable from an undeformed state in which the locking member extends outwardly and distally from the knife carrier to a deformed state in which the locking member is substantially aligned with a longitudinal axis of the knife carrier.

In certain embodiments, the locking member is positioned distally of the stop surface of the staple actuator when the staple actuator and the knife carrier are in their retracted positions, wherein the locking member is movable from the undeformed state to the deformed state to allow the locking member to pass proximally by the staple actuator when the staple actuator is in its advanced position and the knife carrier is moved from its advanced position to its retracted position.

In embodiments, the knife carrier includes a hook member that is aligned with the stop surface such that movement of the knife carrier from its retracted position to its advanced position moves the staple actuator from its retracted position to its advanced position.

In some embodiments, the locking member is supported on the knife carrier in cantilevered fashion.

In certain embodiments, the locking member is formed from a flat leaf spring.

In embodiments, the locking member is formed from wire having a cylindrical cross-section.

Another aspect of the disclosure is directed to a surgical stapling device that includes an adaptor assembly and a reload assembly. The adaptor assembly includes a proximal end portion, a distal end portion, and a knife driver. The knife driver is movable between a retracted position and an advance position. The reload assembly is supported on the distal end portion of the adaptor assembly and includes a shell housing, a staple cartridge, a staple pusher, a staple actuator, a knife carrier supporting a knife, and a locking member. The shell housing includes an outer housing portion and an inner housing portion that define an annular cavity. The staple cartridge is supported on the shell housing and includes a plurality of staples. The staple pusher is supported within the annular cavity and is movable from a retracted position to an advanced position to eject staples from the staple cartridge. The staple actuator is supported within the annular cavity in a position to engage the staple pusher and defines a through bore. The staple actuator is movable from a retracted position to an advanced position to move the staple pusher from its retracted position to its advanced position. The knife carrier is supported within the through bore and includes a distal portion and a proximal portion. The knife carrier is movable between a retracted position and an advanced position in response to movement of the knife driver from its retracted position to its advanced position. The locking member is supported on the inner housing portion and includes a lockout latch that is movable from an undeformed state to a deformed state in response to movement of the knife driver from its retracted position towards its advanced position. In the undeformed state, the lockout latch is engaged with the knife carrier to prevent advancement of the knife carrier within the shell housing.

In embodiments, the proximal portion of the knife carrier includes resilient longitudinal body portions that define an annular recess, and the knife driver has a distal end portion including an annular rib, wherein the annular rib being received within the annular recesses to couple the knife driver to the knife carrier when the knife driver is moved from its retracted position towards its advanced position.

In some embodiments, the lockout latch supports a first tab and the knife carrier defines a notch, wherein the first tab being received within the notch when the lockout latch is in its undeformed state to prevent advancement of the knife carrier within the shell housing.

In certain embodiments, the lockout latch includes a second tab having an angled proximally facing surface, and the knife driver is movable from its retracted position towards its advanced position into engagement with the second tab to move the lockout latch from the undeformed state to the deformed state.

In embodiments, the proximal end portion of each of the longitudinal body portions includes a tapered surface that is positioned proximally of the annular recesses, wherein the tapered surfaces are aligned with and positioned distally of the distal end portion of the knife driver when the knife driver and the knife carrier are in their retracted positions.

In some embodiments, a bushing is supported on the inner housing portion of the shell housing and the locking member is supported on the bushing.

In certain embodiments, the bushing includes a protrusion and the locking member includes an annular ring defining a cutout, wherein the annular ring is received about the bushing and the protrusion is received within the cutout to prevent the locking member from rotating in relation to the bushing.

In embodiments, the locking member includes an annular ring supported on the bushing, and the lockout latch of the locking member includes a transverse portion and a proximally extending longitudinal portion that extends from the transverse portion in cantilevered fashion.

In some embodiments, the transverse portion of the lockout latch extends through a slot defined by the longitudinal body portions of the knife carrier and the proximally extending longitudinal portion of the lockout latch supports a latch member that is positioned within one of the annular recesses of one of the longitudinal body portions of the knife carrier when the lockout latch is in the undeformed state to obstruct distal movement of the knife carrier within the shell housing.

In certain embodiments, the locking member includes a cam surface that is positioned adjacent to the latch member to be engaged by the distal end portion of the knife driver when the knife driver is moved from its retracted position towards its advanced position to move the locking member from the undeformed state to the deformed state.

Another aspect of the disclosure is directed to a reload assembly including a shell housing, a staple cartridge, a staple pusher, a staple actuator, a knife carrier, and a locking member. The shell housing includes an outer housing portion and an inner housing portion that define an annular cavity. The staple cartridge is supported on the shell housing and includes a plurality of staples. The staple pusher is supported within the annular cavity and is movable from a retracted position to an advanced position to eject staples from the staple cartridge. The staple actuator is supported within the annular cavity in a position to engage the staple pusher and defines a through bore. The staple actuator is movable from a retracted position to an advanced position to move the staple pusher from its retracted position to its advanced position. The knife carrier is supported within the through bore and includes a distal portion and a proximal portion. The knife carrier supports a knife and is movable between a retracted position and an advanced position. The locking member is supported on the inner housing portion and includes a lockout latch that is movable from an undeformed state to a deformed state in response to firing of a surgical stapling device, wherein in the undeformed state, the lockout latch is engaged with the knife carrier to prevent advancement of the knife carrier within the shell housing.

Various embodiments of the disclosed reload assembly for a surgical stapling device are described herein below with reference to the drawings, wherein:.

The disclosed reload assembly for a surgical 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 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 disclosure in virtually any appropriately detailed structure. In addition, directional terms such as front, rear, upper, lower, top, bottom, distal, proximal, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

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.

<FIG> illustrate a circular stapling device <NUM> including an exemplary embodiment of the disclosed reload assembly shown generally as reload assembly <NUM>. The stapling device <NUM> includes a handle assembly <NUM>, an elongate body or adaptor assembly <NUM>, the reload assembly <NUM>, and an anvil assembly <NUM> that is supported for movement in relation to the reload assembly <NUM> between spaced and approximated positions as is known in the art. In embodiments, the reload assembly <NUM> includes a proximal portion <NUM> that is releasably coupled to a distal portion 14a of the elongate body <NUM>. In some embodiments, the handle assembly <NUM> includes a stationary grip <NUM> that supports actuation buttons <NUM> for controlling operation of various functions of the stapling device <NUM> including approximation of the reload and anvil assemblies <NUM> and <NUM>, respectively, firing of staples from the reload assembly <NUM>, and cutting or coring of tissue.

The stapling device <NUM> is illustrated as an electrically powered stapling device including an electrically powered handle assembly <NUM> that may support one or more batteries (not shown). The elongate body <NUM> is in the form of an adaptor assembly that translates power from the handle assembly <NUM> to the reload and anvil assemblies <NUM>, <NUM>, respectively. Examples of electrically powered stapling devices can be found in <CIT><CIT>, and <CIT>, and <CIT>. Alternately, it is envisioned that the reload assembly could also be incorporated into a manually powered stapling device such as disclosed in <CIT> (the '<NUM> Patent) or a stapling device that is configured for use with a robotic system such as disclosed in <CIT> that does not include a handle assembly.

<FIG> and <FIG> illustrate the reload assembly <NUM> which includes a shell housing <NUM>, a staple actuator <NUM>, a staple pushing member 112a, 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 staple of the plurality of staples <NUM>. The staple actuator <NUM> and the staple pushing member 112a together define a longitudinal through bore <NUM> (<FIG>). The staple actuator <NUM> has a distal portion that abuts a proximal portion of the staple pushing member 112a such that distal movement of the staple actuator <NUM> within the shell housing <NUM> causes distal movement of the staple pushing member 112a within the shell housing <NUM>. The staple pushing member 112a of the reload assembly <NUM> has a plurality of fingers <NUM>. Each of the plurality of fingers <NUM> is received within a respective one of the staple pockets <NUM> of the staple cartridge <NUM> and is movable through the respective staple pocket <NUM> to eject the staples <NUM> from the staple pockets <NUM> when the staple pushing member 112a is moved from a retracted position to an advanced position within the shell housing <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> (<FIG>) between the outer and inner housing portions <NUM> and <NUM>. The staple actuator <NUM> and the staple pushing member 112a are movable within the annular cavity <NUM> of the shell housing <NUM> from retracted positions to advanced positions to eject the staples <NUM> from the staple cartridge <NUM>.

The annular knife <NUM> is supported about an outer surface of the knife carrier <NUM>, defines a cylindrical cavity <NUM>, and includes a distal cutting edge 117a. In embodiments, the annular knife <NUM> includes inwardly extending tangs 117b that are received within pockets 114a defined in an outer surface of the knife carrier <NUM> to secure the annular knife <NUM> to the knife carrier <NUM>. The knife carrier <NUM> and annular knife <NUM> are positioned within the through bore <NUM> of the staple actuator <NUM> and are movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge <NUM>.

The inner housing portion <NUM> of the shell housing <NUM> defines a through bore <NUM> (<FIG>) that receives an anvil shaft (not shown) of the anvil assembly <NUM>. For a more detailed description of an exemplary anvil assembly <NUM>, see, e.g., the '<NUM> Patent. The through bore <NUM> has a proximal portion that receives a bushing <NUM> (<FIG>) that defines a through bore 150a that is coaxial and forms an extension of the through bore <NUM> of the inner housing portion <NUM>. In embodiments, the bushing <NUM> is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion <NUM> of the shell housing <NUM> and includes an annular flange 152a.

The shell housing <NUM> includes a proximal portion <NUM> (<FIG>) that supports a coupling mechanism <NUM> (<FIG>) that is operable to releasably couple the reload assembly <NUM> to the adaptor assembly <NUM> of the stapling device <NUM> (<FIG>). The coupling mechanism <NUM> allows for removal and replacement of the reload assembly <NUM> to facilitate reuse of the stapling device <NUM>. The coupling mechanism <NUM> includes a retaining member <NUM> and a coupling member <NUM>. The coupling member <NUM> is received about the proximal portion <NUM> (<FIG>) of the shell housing <NUM> and is configured to engage the distal portion 14a (<FIG>) of the adaptor assembly <NUM> to couple the reload assembly <NUM> to the adaptor assembly <NUM>. It is envisioned that other coupling mechanisms can be used to secure the reload assembly <NUM> to the adaptor assembly <NUM>. Alternately, the reload assembly <NUM> can be non-removably secured to the adaptor assembly <NUM>.

The reload assembly <NUM> may include an e-prom holder <NUM> (<FIG>) that is supported on the shell housing <NUM> and is configured to support an e-prom (not shown). As is known in the art, an e-prom can communicate with the adaptor assembly <NUM> to provide information to the adaptor assembly <NUM> and the handle assembly <NUM> regarding characteristics of the reload assembly <NUM>. In some embodiments, the e-prom holder <NUM>, may define a cylindrical collar that is received about a distal portion of the bushing <NUM>.

<FIG> illustrate the knife carrier <NUM> which includes a plurality of spaced resilient longitudinal body portions <NUM> that are spaced from each other and together define a central bore <NUM>. The central bore <NUM> of the knife carrier <NUM> receives the inner housing portion <NUM> of the shell housing <NUM> such that the knife carrier <NUM> is movable about the inner housing portion <NUM> of the shell housing <NUM> between a retracted position (<FIG>) and an advanced position (<FIG>). The longitudinal body portions <NUM> of the knife carrier <NUM> define slots <NUM> that receive guide portions (not shown) of the shell housing <NUM> to limit the knife carrier <NUM> to longitudinal movement within the shell housing <NUM>. In embodiments, the knife carrier <NUM> includes hook members <NUM> that are positioned to engage the staple actuator <NUM> to move the staple actuator <NUM> from its retracted position to its advanced position. The hook members <NUM> extend radially outwardly from the knife carrier <NUM> towards the staple actuator <NUM> within the annular cavity <NUM> (<FIG>) of the shell housing <NUM>. Each of the hook members <NUM> includes an engagement surface 178a and supports a locking member <NUM>. In embodiments, the locking members <NUM> are positioned distally of the engagement surfaces 178a of the hook members <NUM> and extend outwardly and distally from the knife carrier <NUM> towards the staple actuator <NUM> at an acute angle. The locking members <NUM> may be formed of a resilient material that can be deformed inwardly via engagement with staple actuator <NUM> towards an outer surface of the knife carrier <NUM> but is sufficiently rigid to prevent readvancement of the knife carrier <NUM> as described below.

<FIG> illustrates the staple actuator <NUM> which includes a body <NUM> that is also received about the inner housing portion <NUM> (<FIG>) of the shell housing <NUM> and is movable from a retracted position (<FIG>) to an advanced position (<FIG>) in response to movement of the knife carrier <NUM> from its retracted position to its advanced position. The body <NUM> defines a plurality of guide slots 182a and at least one stop surface <NUM>. In some embodiments, the at least one stop surface <NUM> is positioned at a distal end of a channel <NUM> formed in the body <NUM>. The channel <NUM> is positioned to receive the hook members <NUM>. The guide slots 182a of the staple actuator <NUM> receive the guide members (not shown) of the shell housing <NUM> to limit the staple actuator <NUM> to longitudinal movement within the shell housing <NUM>. The at least one stop surface <NUM> of the staple actuator <NUM> is longitudinally aligned with the engagement surfaces 178a of the hook members <NUM> (<FIG>) of the knife carrier <NUM> such that advancement of the knife carrier <NUM> within the through bore <NUM> of the staple actuator <NUM> causes the engagement surfaces 178a of the hook members <NUM> of the knife carrier <NUM> to engage the at least one stop surface <NUM> of the staple actuator <NUM> to advance the staple actuator <NUM> within the shell housing <NUM> from its retraced position to its advanced position.

<FIG> illustrates the reload assembly <NUM> in a pre-fired condition with the knife carrier <NUM> and staple actuator <NUM> of the reload assembly <NUM> (<FIG>) in retracted positions and the locking member <NUM> in an unlatched position located distally of the at least one stop surface <NUM> of the staple actuator <NUM>. When the knife carrier <NUM> and the staple actuator <NUM> are in pre-fired retracted positions, the engagement surface 178a of each of the hook members <NUM> is aligned with and spaced proximally of the respective stop surface <NUM> of the staple actuator <NUM> and each of the locking members <NUM> is positioned distally of a respective stop surface <NUM> and is in an undeformed state.

<FIG> illustrates the reload assembly <NUM> as the staple actuator <NUM> and the knife carrier <NUM> are moved to their advanced positions. As the knife carrier <NUM> is moved distally within the shell housing <NUM> to its advanced position by a knife carrier driver (not shown) of the stapling device <NUM> (<FIG>) in the direction indicated by arrows "A", the engagement surfaces 178a of the hook members <NUM> engage the stop surfaces <NUM> of the staple actuator <NUM> such that the staple actuator <NUM> is moved distally with the knife carrier <NUM> in the direction indicated by arrows "B". As the staple actuator <NUM> moves distally within the shell housing <NUM>, the staple pushing member 112a is moved distally in the direction indicated by arrows "C" to advance the plurality of fingers <NUM> of the staple pushing member 112a through the staple pockets <NUM> of the staple cartridge <NUM> to eject the staples <NUM> from the staple cartridge <NUM> into the anvil assembly <NUM>. As illustrated, the annular knife <NUM> which is secured to the knife carrier <NUM> is moved distally with the knife carrier <NUM> in the direction indicated by arrows "D" to cut tissue.

<FIG> and <FIG> illustrate the reload assembly <NUM> as the knife carrier <NUM> is moved from its advanced position to its retracted position after the reload assembly is fired. When the knife carrier <NUM> is moved proximally in the direction indicated by arrows "E" towards its retracted position, the annular knife <NUM> is also moved proximally to a position located within the shell housing <NUM>. In this position, a clinician is protected from inadvertent injury caused by the cutting edge 117a of the annular knife <NUM>. As the knife carrier <NUM> and annular knife <NUM> are moved proximally within the shell housing <NUM>, the staple actuator <NUM> remains in an advanced position within the shell housing <NUM>. As the knife carrier <NUM> moves proximally in relation to the staple actuator <NUM>, each of the locking members <NUM> engages a portion of the staple actuator <NUM> that defines a respective stop surface <NUM> such that the locking members <NUM> are deformed inwardly towards the outer surface of the knife carrier <NUM> in the direction indicated by arrow "F" in <FIG>. In their deformed state, the locking members <NUM> pass inwardly and move proximally beyond the respective stop surfaces <NUM> (<FIG>). When the locking members <NUM> move proximally past the respective stop surfaces <NUM>, the locking members <NUM> spring outwardly to their undeformed state in the direction indicated by arrow "G" in <FIG> to positions aligned with the respective stop surfaces <NUM>. In this position, the locking members <NUM> prevent readvancement of the knife carrier <NUM> to retain the annular knife <NUM> within the shell housing <NUM> of the reload assembly <NUM>.

The locking members <NUM> may be provided in a variety of different configurations and formed of a variety of different materials. In addition, the locking members <NUM> may be formed integrally with the knife carrier <NUM> or formed separately from the knife carrier <NUM> and secured to the knife carrier <NUM> using any known fastening technique. For example as illustrated in <FIG>, the locking member <NUM> may be in the form of a flat or rectangular leaf spring that is formed from a deformable resilient material such as spring steel or plastic and received within a recess <NUM> formed in the knife carrier <NUM> in cantilevered fashion. Alternately, other materials and configurations may be used to form the locking member <NUM>. In one alternate embodiment shown in <FIG>, each of the locking members <NUM>' is formed from a resilient wire. In embodiments, the resilient wire <NUM>' has a circular cross-sectional shape and is received within a recess <NUM>' formed in the knife carrier <NUM> in cantilevered fashion. Alternately other cross-sectional shapes are envisioned.

<FIG> illustrate another exemplary embodiment of the disclosed reload assembly shown generally as reload assembly <NUM>. <FIG> illustrates the reload assembly <NUM> which can be used with the stapling device <NUM> (<FIG>) and includes a shell housing <NUM>, a staple actuator <NUM>, a staple pushing member 212a, 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 adaptor assembly <NUM> (<FIG>) includes a knife carrier driver <NUM> that interacts with the knife carrier <NUM> to move the knife carrier <NUM> within the shell housing <NUM>. The staple cartridge <NUM> is annular and defines annular rows of staple pockets <NUM>. Each of the staple pockets <NUM> supports one staple of the plurality of staples <NUM>. The staple actuator <NUM> and the staple pushing member 212a together define a longitudinal through bore <NUM> (<FIG>). The staple actuator <NUM> has a distal portion that abuts a proximal portion of the staple pushing member 212a such that distal movement of the staple actuator <NUM> within the shell housing <NUM> causes distal movement of the staple pushing member 212a within the shell housing <NUM>. The staple pushing member 212a of the reload assembly <NUM> has a plurality of fingers <NUM>. Each of the plurality of fingers <NUM> is received within a respective one of the staple pockets <NUM> of the staple cartridge <NUM> and is movable through the respective staple pocket <NUM> to eject a staple <NUM> from the respective staple pocket <NUM> when the staple pushing member 212a is moved from a retracted position to an advanced position within the shell housing <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> between the outer and inner housing portions <NUM> and <NUM>. The staple actuator <NUM> and the staple pushing member 212a are movable within the annular cavity <NUM> of the shell housing <NUM> from a retracted position to an advanced position to eject the staples <NUM> from the staple cartridge <NUM>.

The annular knife <NUM> is supported about an outer surface of the knife carrier <NUM>, defines a cylindrical cavity <NUM>, and includes a distal cutting edge 217a. The knife carrier <NUM> and annular knife <NUM> are positioned within the through bore <NUM> of the staple actuator <NUM> and movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge <NUM>.

The inner housing portion <NUM> of the shell housing <NUM> defines a through bore <NUM> that receives an anvil shaft (not shown) of the anvil assembly <NUM> (<FIG>). For a more detailed description of an exemplary anvil assembly <NUM>, see, e.g., the '<NUM> Patent. The through bore <NUM> has a proximal portion that receives a bushing <NUM> that defines a through bore 250a that is coaxial and forms an extension of the through bore <NUM> of the inner housing portion <NUM>. In embodiments, the bushing <NUM> is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion <NUM> of the shell housing <NUM> and includes an annular flange 252a. The annular flange <NUM> includes a protrusion <NUM>.

The shell housing <NUM> includes a proximal portion <NUM> that supports a coupling mechanism <NUM> that is operable to releasably couple the reload assembly <NUM> to the adaptor assembly <NUM> of the stapling device <NUM> (<FIG>). The coupling mechanism <NUM> allows for removal and replacement of the reload assembly <NUM> to facilitate reuse of the stapling device <NUM>. The coupling mechanism <NUM> includes a retaining member <NUM> and a coupling member <NUM>. The coupling member <NUM> is received about the proximal portion <NUM> of the shell housing <NUM> and is configured to engage the distal portion 14a (<FIG>) of the adaptor assembly <NUM> to couple the reload assembly <NUM> to the adaptor assembly <NUM>. It is envisioned that other coupling mechanisms can be used to secure the reload assembly <NUM> to the adaptor assembly <NUM>. Alternately, the reload assembly <NUM> can be non-removably secured to the adaptor assembly <NUM>.

The reload assembly <NUM> may include an e-prom holder <NUM> that is supported on the shell housing <NUM> and is configured to support an e-prom (not shown). As is known in the art, an e-prom communicates with the adaptor assembly <NUM> (<FIG>) to provide information to the adaptor assembly <NUM> and the handle assembly <NUM> (<FIG>) regarding characteristics of the reload assembly <NUM>. In some embodiments, the e-prom holder <NUM> can be received about a distal portion of the bushing <NUM>.

The knife carrier <NUM> includes a plurality of resilient longitudinal body portions <NUM> that are spaced from each other and together define a central bore <NUM>. The central bore <NUM> of the knife carrier <NUM> receives the inner housing portion <NUM> of the shell housing <NUM> such that the knife carrier <NUM> is movable about the inner housing portion <NUM> of the shell housing <NUM> between a retracted position and an advanced position. The longitudinal body portions <NUM> of the knife carrier <NUM> are resilient and spaced from each other to define slots <NUM> that receive guide portions (not shown) of the shell housing <NUM> to limit the knife carrier <NUM> to longitudinal movement within the shell housing <NUM>.

The staple actuator <NUM> includes a body that is also received about the inner housing portion <NUM> of the shell housing <NUM> and is movable within the shell housing <NUM> from a retracted position to an advanced position. The body defines a plurality of guide slots <NUM> that receive the guide members (not shown) of the shell housing <NUM> to limit the staple actuator <NUM> to longitudinal movement within the shell housing <NUM>.

<FIG> illustrate a locking member <NUM> of the reload assembly <NUM> that includes a body <NUM> having an annular ring <NUM> and a lockout latch <NUM>. The annular ring <NUM> is received about a proximal portion of the bushing <NUM> and is positioned in abutting relation to the flange 252a to secure the locking member <NUM> to the bushing <NUM> (<FIG>). The annular ring <NUM> defines a cutout <NUM> which may be rectangular in shape and receives the protrusion <NUM> formed on the bushing <NUM> to prevent rotation of the locking member <NUM> in relation to the bushing <NUM> (<FIG>). In embodiments, the annular ring <NUM> of the locking member <NUM> may include a slot <NUM> to allow for radial flexing of the annular ring <NUM> to facilitate placement of the locking member <NUM> in a friction fit manner about the bushing <NUM>.

The lockout latch <NUM> is formed of a resilient material and extends in cantilevered fashion from the annular ring <NUM>. In embodiments, the lockout latch <NUM> is integrally formed with the annular ring <NUM> of the locking member. Alternately, the lockout latch <NUM> can be pivotably secured to the annular ring <NUM> in cantilevered fashion using, e.g., a hinge mechanism (not shown). The lockout latch <NUM> includes a first tab <NUM> that has an angled proximally facing surface <NUM> and a second tab <NUM> that has a substantially perpendicular proximally facing surface <NUM>. In embodiments, the first tab <NUM> has a generally triangular shape and the second tab <NUM> has a generally rectangular shape. Alternately, other configurations are envisioned. The lockout latch <NUM> is movable from an unbiased position in which the lockout latch <NUM> is spaced outwardly of and extends along an outer surface of the bushing <NUM> to a biased position in which the lockout latch <NUM> is biased inwardly towards the outer surface of the bushing <NUM>.

<FIG> illustrate a proximal portion of the longitudinal body portions <NUM> of the knife carrier <NUM>. Each of the longitudinal body portions <NUM> of the knife carrier <NUM> defines an annular recess <NUM> and a tapered surface <NUM> that is positioned proximally of the annular recess <NUM>. The knife carrier driver <NUM> (<FIG>) of the adaptor assembly <NUM> includes an inner annular rib <NUM> that is received within the annular recesses <NUM> of the longitudinal body portions <NUM> to couple the knife carrier driver <NUM> to the knife carrier <NUM> when the stapling device <NUM> (<FIG>) is actuated to fire staples <NUM> (<FIG>) from the reload assembly <NUM>. One of the longitudinal body portions <NUM> also defines a notch <NUM> that receives the second tab <NUM> of the locking member <NUM> when the knife carrier <NUM> is in a retracted position within the shell housing <NUM> to obstruct distal movement of the knife carrier within the shell housing <NUM>.

<FIG> illustrate the reload assembly <NUM> in a pre-fired state with the knife carrier <NUM>, the knife driver <NUM>, the staple actuator <NUM>, and the staple pushing member 212a in their retracted positions. In the pre-fired state, the distal end of the knife driver <NUM> is positioned adjacent to a proximal end of the knife carrier <NUM> and adjacent to the lockout latch <NUM> of the locking member <NUM>. In this position, the inner annular rib <NUM> at the distal end portion of the knife driver <NUM> is spaced proximally of the annular recesses <NUM> formed in the longitudinal body portions <NUM> of the knife carrier <NUM>. In addition, the lockout latch <NUM> is in its undeformed state with the first tab <NUM> of the lockout latch <NUM> located adjacent to the distal end of the knife driver <NUM> and the second tab <NUM> received within the notch <NUM> formed in the longitudinal body portion <NUM> of the knife carrier <NUM>. When the second tab <NUM> positioned within the notch <NUM>, the proximally facing surface <NUM> of the second tab <NUM> obstructs advancement of the knife carrier <NUM> within the shell housing <NUM>.

<FIG> illustrate the reload assembly <NUM> as the knife driver <NUM> is moved towards its advanced position to move the knife carrier <NUM> and the annular knife <NUM> toward their advanced positions. When the knife driver <NUM> is advanced within the shell housing <NUM> in the direction indicated by arrow "H" in <FIG>, the distal end portion of the knife driver <NUM> engages the tapered surface <NUM> at the proximal end portion of each of the longitudinal body portions <NUM> of the knife carrier <NUM> to urge the longitudinal body portions <NUM> inwardly in the direction indicated by arrow "I" in <FIG>. This allows the inner annular rib <NUM> of the knife driver <NUM> to pass into the annular recesses <NUM> of the longitudinal body portions <NUM> of the knife carrier <NUM> to couple the distal end portion of the knife driver <NUM> to the proximal end portion of the knife carrier <NUM>.

As the knife driver <NUM> continues to advance within the shell housing <NUM> in the direction indicated by arrow "H" in <FIG>, the distal end portion of the knife driver <NUM> also engages the angled proximally facing surface <NUM> of the first tab <NUM> to urge the lockout latch <NUM> inwardly in the direction indicated by arrow "J" towards its deformed state. As the lockout latch <NUM> moves inwardly towards the bushing <NUM> to its deformed state, the second tab <NUM> of the lockout latch <NUM> is removed from the notch <NUM> formed in the proximal end of the respective longitudinal body portion <NUM> of the knife carrier <NUM>. In this position, the second tab <NUM> does not obstruct advancement of the knife carrier <NUM> within the shell housing <NUM>. As the knife driver <NUM> advances within the shell housing <NUM>, engagement between the knife driver <NUM> and the first tab <NUM> retains the lockout latch <NUM> in its deformed state with the second tab <NUM> removed from the notch <NUM> to allow the knife carrier <NUM> and the knife driver <NUM> to move to their advanced positions to advance the annular knife <NUM> to its advanced position extending from the shell housing <NUM> to cut tissue.

<FIG> illustrates the reload assembly <NUM> as the knife carrier <NUM> and the knife driver <NUM> are moved from their advanced positions back to their retracted positions in the direction indicated by arrows "K". This movement retracts the annular knife <NUM> into the shell housing <NUM>. When the knife carrier <NUM> reaches its retracted position and cannot move further proximally, the longitudinal body portions <NUM> are forced inwardly by the inner annular rib <NUM> of the knife driver <NUM> such that the inner annular rib <NUM> is removed from the annular recesses <NUM> of the longitudinal body portions <NUM> of the knife driver <NUM> to uncouple the knife driver <NUM> from the knife carrier <NUM>. When the notch <NUM> in the longitudinal body portion <NUM> of the knife carrier <NUM> becomes aligned with the second tab <NUM> of the lockout latch <NUM> of the locking member <NUM>, the lockout latch <NUM> pivots in the direction indicated by arrow "L" in <FIG> to reposition the second tab <NUM> within the notch <NUM>. Once again, this obstructs advancement of the knife carrier <NUM> to prevent readvancement of the annular knife <NUM> from within the shell housing <NUM>.

<FIG> illustrate another exemplary embodiment of the disclosed reload assembly shown generally as reload assembly <NUM> which can be used with the stapling device <NUM> (<FIG>). <FIG> and <FIG> illustrate another exemplary embodiment of the reload assembly shown generally as reload assembly <NUM>. Reload assembly <NUM> includes a shell housing <NUM>, a staple actuator <NUM>, a staple pushing member 412a, 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 adaptor assembly <NUM> (<FIG>) includes a knife carrier driver <NUM> (<FIG>) that interacts with the knife carrier <NUM> to move the knife carrier <NUM> from a retracted position to an advanced position within the shell housing <NUM> as described in detail below. 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 staple actuator <NUM> and the staple pushing member 412a together define a longitudinal through bore <NUM> (<FIG>). The staple actuator <NUM> has a distal portion that abuts a proximal portion of the staple pushing member 412a such that distal movement of the staple actuator <NUM> within the shell housing <NUM> causes distal movement of the staple pushing member 412a within the shell housing <NUM>. The staple pushing member 412a of the reload assembly <NUM> has a plurality of fingers <NUM>. Each of the plurality of fingers <NUM> is received within a respective one of the staple pockets <NUM> of the staple cartridge <NUM> and is movable through the respective staple pocket <NUM> to eject a staple <NUM> from a respective pocket <NUM> of the staple cartridge <NUM> when the staple pushing member 412a is moved from a retracted position to an advanced position within the shell housing <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> (<FIG>) between the outer and inner housing portions <NUM> and <NUM>. The staple actuator <NUM> and the staple pushing member 412a are movable within the annular cavity <NUM> of the shell housing <NUM> from a retracted position to an advanced position to eject the staples <NUM> from the staple cartridge <NUM>.

The annular knife <NUM> is supported about an outer surface of the knife carrier <NUM>, defines a cylindrical cavity <NUM>, and includes an annular cutting edge 417a. The knife carrier <NUM> and annular knife <NUM> are positioned within the through bore <NUM> of the staple actuator <NUM> and are movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge <NUM>.

The inner housing portion <NUM> of the shell housing <NUM> defines a through bore <NUM> that receives an anvil shaft (not shown) of the anvil assembly <NUM> (<FIG>). The through bore <NUM> has a proximal portion that receives a bushing <NUM> that defines a through bore 450a that is coaxial with and forms an extension of the through bore <NUM> of the inner housing portion <NUM>. In embodiments, the bushing <NUM> is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion <NUM> of the shell housing <NUM> and includes an annular flange 452a. The shell housing <NUM> includes a proximal portion <NUM> that supports a coupling mechanism <NUM> that is operable to releasably couple the reload assembly <NUM> to the adaptor assembly <NUM> of the stapling device <NUM> (<FIG>). The coupling mechanism <NUM> allows for removal and replacement of the reload assembly <NUM> to facilitate reuse of the stapling device <NUM> (<FIG>). The coupling mechanism <NUM> includes a retaining member <NUM> and a coupling member <NUM>. The coupling member <NUM> is received about the proximal portion <NUM> of the shell housing <NUM> and is configured to engage the distal portion 14a (<FIG>) of the adaptor assembly <NUM> to couple the reload assembly <NUM> to the adaptor assembly <NUM>. It is envisioned that other coupling mechanisms can be used to secure the reload assembly <NUM> to the adaptor assembly <NUM>. Alternately, the reload assembly <NUM> can be fixedly secured to the adaptor assembly <NUM>.

The knife carrier <NUM> includes a plurality of spaced longitudinal body portions <NUM> that are spaced from each other and together define a central bore <NUM> (<FIG>). The central bore <NUM> of the knife carrier <NUM> receives the inner housing portion <NUM> of the shell housing <NUM> such that the knife carrier <NUM> is movable about the inner housing portion <NUM> of the shell housing <NUM> between a retracted position and an advanced position. The longitudinal body portions <NUM> of the knife carrier <NUM> are spaced from each other to define slots <NUM> that receive guide portions (not shown) of the shell housing <NUM> to limit the knife carrier <NUM> to longitudinal movement within the shell housing <NUM>.

The staple actuator <NUM> includes a body that is also received about the inner housing portion <NUM> of the shell housing <NUM> and is movable within the shell housing <NUM> from a retracted position to an advanced position. The body of the staple actuator <NUM> defines a plurality of guide slots (not shown) that receive the guide members (not shown) of the shell housing <NUM> to limit the staple actuator <NUM> to longitudinal movement within the shell housing <NUM>.

<FIG> illustrate a locking member <NUM> of the reload assembly <NUM> that includes a body <NUM> having an annular ring <NUM> and a lockout latch <NUM>. The annular ring <NUM> is received about a proximal portion of the bushing <NUM> (<FIG>) and is positioned in abutting relation to the flange 452a to secure the locking member <NUM> to the bushing <NUM> (<FIG>). The annular ring <NUM> of the locking member <NUM> may include a slot <NUM> to allow for flexing of the annular ring <NUM> to facilitate placement of the locking member <NUM> in a friction fit manner about the bushing <NUM>.

The lockout latch <NUM> is formed of a resilient material and extends from the annular ring <NUM>. In embodiments, the lockout latch <NUM> is integrally formed with the annular ring <NUM> of the locking member <NUM> and includes a first longitudinal portion <NUM>, a transverse portion <NUM>, and a second longitudinal portion <NUM>. The first longitudinal portion <NUM> has a first end coupled to the annular ring <NUM> and extends distally from the annular ring <NUM>. The transverse portion <NUM> of the lockout latch <NUM> extends from a second end of the first longitudinal portion <NUM> radially outward from the bushing <NUM>. The second longitudinal portion <NUM> extends proximally from the transverse portion <NUM> and has a proximal end portion that supports a latch member <NUM>. In embodiments, the latch member <NUM> includes a cam surface 494a that is angled radially outwardly from the second longitudinal portion <NUM> and defines an axis that is transverse to axes defined by the first and second longitudinal portions <NUM> and <NUM> of the locking member <NUM> and transverse to the transverse portion <NUM>. In embodiments, the locking member <NUM> can be of integral construction. Alternately, the lockout latch <NUM> can be pivotably secured to the annular ring <NUM> using any of a variety of fastening techniques.

In embodiments, the first and second longitudinal portions <NUM> and <NUM> are aligned with one of the longitudinal slots <NUM> defined between the longitudinal body portions <NUM> of the knife carrier <NUM> and the transverse portion <NUM> extends through the respective slot <NUM>. In this configuration, the first longitudinal portion <NUM> of the locking member <NUM> is positioned within the knife carrier <NUM> and the second longitudinal portion <NUM> is positioned along an outer surface of the knife carrier <NUM> and supports the latch member <NUM> in cantilevered fashion.

<FIG> and <FIG> illustrate a proximal portion of the longitudinal body portions <NUM> of the knife carrier <NUM>. Each of the longitudinal body portions <NUM> of the knife carrier <NUM> defines an annular recess <NUM> and includes a tapered proximal surface <NUM> that is positioned proximally of the annular recess <NUM>. The annular recess <NUM> is defined in part by a proximal wall 500a. The knife driver <NUM> (<FIG>) of the adaptor assembly <NUM> (<FIG>) includes an inner annular rib <NUM> that is received within the annular recesses <NUM> of the longitudinal body portions <NUM> to couple the knife driver <NUM> to the knife carrier <NUM> when the stapling device <NUM> (<FIG>) is actuated to fire staples (not shown) from the reload assembly <NUM>. The latch member <NUM> is received within the annular recess <NUM> (<FIG>) of the knife carrier <NUM> when the knife carrier <NUM> is in a pre-fired retracted position to obstruct distal movement of the knife carrier <NUM> within the shell housing <NUM> (<FIG>). More specifically, the latch member <NUM> is positioned to engage the proximal wall 500a defining the annular recess <NUM> in the knife carrier <NUM> to prevent advancement of the knife carrier <NUM> within the shell housing <NUM>.

<FIG> and <FIG> illustrate the reload assembly <NUM> in the pre-fired state with the knife carrier <NUM>, the knife driver <NUM>, the staple actuator <NUM>, and the staple pushing member 412a in their retracted positions. In the pre-fired state, the distal end of the knife driver <NUM> is positioned adjacent to a proximal end of the knife carrier <NUM> and adjacent to the lockout latch <NUM> of the locking member <NUM>. In this position, the inner annular rib <NUM> at the distal end portion of the knife driver <NUM> is spaced proximally of the annular recesses <NUM> formed in the longitudinal body portions <NUM> of the knife carrier <NUM>. In addition, the lockout latch <NUM> is in its undeformed state with the latch member <NUM> of the lockout latch <NUM> received within the annular recess <NUM> of the knife carrier <NUM>. In this position, the latch member <NUM> is aligned with the proximal wall 500a defining the annular recess <NUM> to prevent advancement of the knife carrier <NUM> from its retracted position toward its advanced position. In its retracted position, the annular knife <NUM> including the cutting edge 417a is shielded within the shell housing <NUM>.

<FIG> illustrate the reload assembly <NUM> as the knife driver <NUM> is moved from its retracted position towards its advanced position to move the knife carrier <NUM> and the annular knife <NUM> toward their advanced positions. When the knife driver <NUM> is advanced within the shell housing <NUM> in the direction indicated by arrow "M" in <FIG>, the distal end portion of the knife driver <NUM> engages the tapered surface <NUM> at the proximal end portion of each of the longitudinal body portions <NUM> of the knife carrier <NUM> to urge the longitudinal body portions <NUM> inwardly in the direction indicated by arrow "N" in <FIG>. This allows the inner annular rib <NUM> of the knife driver <NUM> to pass into the annular recesses <NUM> of the longitudinal body portions <NUM> of the knife carrier <NUM> to couple the distal end portion of the knife driver <NUM> to the proximal end portion of the knife carrier <NUM> (<FIG>).

As the knife driver <NUM> continues to advance within the shell housing <NUM> in the direction indicated by arrow "M" in <FIG> and <FIG>, the distal end portion of the knife driver <NUM> engages the cam surface 494a of the of the latch member <NUM> to urge the lockout latch <NUM> outwardly in the direction indicated by arrows "O" towards its deformed state. As the lockout latch <NUM> moves outwardly away from the bushing <NUM> to its deformed state, the latch member <NUM> of the lockout latch <NUM> is removed from the annular recess <NUM> formed in the proximal end of the longitudinal body portion <NUM> of the knife carrier <NUM> such that the latch member <NUM> does not obstruct advancement of the knife carrier <NUM> within the shell housing <NUM>. As such, the knife carrier <NUM> and the annular knife <NUM> can be advanced to cut tissue.

<FIG> illustrates the reload assembly <NUM> as the knife carrier <NUM> and the knife driver <NUM> are moved from their advanced positions back to their retracted positions in the direction indicated by arrow "P". This movement retracts the annular knife <NUM> (<FIG>) into the shell housing <NUM>. When the knife carrier <NUM> reaches its retracted position and cannot move further proximally through the shell housing <NUM> (<FIG>), the longitudinal body portions <NUM> are forced inwardly by the inner annular rib <NUM> of the knife driver <NUM> such that the inner annular rib <NUM> is removed from the annular recesses <NUM> of the longitudinal body portions <NUM> of the knife driver <NUM> to uncouple the knife driver <NUM> from the knife carrier <NUM>. In its retracted position, the annular recess <NUM> of the knife carrier <NUM> is aligned with the latch member <NUM> of the lockout latch <NUM> of the lockout member <NUM> such that the lockout latch <NUM> returns to its undeformed state with the latch member <NUM> received within the annular recess <NUM> of adjacent longitudinal body portions <NUM>. Once again, the latch member <NUM> obstructs advancement of the knife carrier <NUM> to prevent readvancement of the annular knife <NUM> from within the shell housing <NUM>.

Claim 1:
A surgical stapling device (<NUM>) comprising:
an adaptor assembly (<NUM>) having a proximal end portion and a distal end portion (14a); and
a reload assembly (<NUM>) supported on the distal end portion of the adaptor assembly, the reload assembly including:
a shell housing (<NUM>) including an outer housing portion (<NUM>) and an inner housing portion (<NUM>), the inner and outer housing portions defining an annular cavity (<NUM>);
a staple cartridge (<NUM>) supporting a plurality of staples (<NUM>);
a staple pusher (112a) supported within the annular cavity (<NUM>) and movable from a retracted position to an advanced position to eject staples (<NUM>) from the staple cartridge (<NUM>);
a staple actuator (<NUM>) supported within the annular cavity (<NUM>) and having a stop surface (<NUM>), the staple actuator positioned to engage the staple pusher (112a) and movable from a retracted position to an advanced position to move the staple pusher (112a) from its retracted position to its advanced position, the staple actuator and the staple pusher defining a through bore (<NUM>);
a knife carrier (<NUM>, <NUM>') supported within the through bore (<NUM>) and movable between a retracted position and an advanced position, the knife carrier defining a longitudinal axis; and
a knife (<NUM>) supported on the knife carrier (<NUM>, <NUM>'),
characterised in that the knife carrier (<NUM>, <NUM>') supports a resilient locking member (<NUM>, <NUM>') the resilient locking member being aligned with the stop surface (<NUM>) on the staple actuator (<NUM>) when the staple actuator is in its advanced position and the knife carrier is in its retracted position to prevent readvancement of the knife carrier.