Reload assembly with knife carrier lockout

Abstract

A surgical stapling device includes a reload assembly that includes a locking member to retain a knife carrier of the reload assembly in a retracted position after the stapling device is fired. The locking member may be supported on an inner housing portion of the shell housing or on a staple pusher assembly of the reload assembly.

Description

FIELD

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.

BACKGROUND

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.

SUMMARY

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.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a side perspective view of a surgical stapling device including an exemplary embodiment of the disclosed reload assembly with the stapling device in a clamped position;

FIG. 2 is a side perspective view of the reload assembly of the stapling device shown in FIG. 1;

FIG. 3 is a side perspective exploded view of the reload assembly shown in FIG. 2;

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG. 3;

FIG. 5 is a side perspective view from the distal end of a knife carrier of the reload assembly shown in FIG. 3;

FIG. 6 is an enlarged view of the indicated area of detail shown in FIG. 5;

FIG. 7 is a side perspective view from the proximal end of a staple actuator of the reload assembly shown in FIG. 3;

FIG. 8 is a cross-sectional view taken along section line 8-8 of FIG. 2 with the reload assembly in a pre-fired state;

FIG. 9 is a cross-sectional view taken along section line 8-8 of FIG. 2 with the reload assembly in a fired state and the knife carrier in an advanced position;

FIG. 10 is a cross-sectional view taken along section line 8-8 of FIG. 2 with the reload assembly in a fired state and the knife carrier moving toward its retracted position;

FIG. 11 is a cross-sectional view taken along section line 8-8 of FIG. 2 with the reload assembly in a fired state and the knife carrier in its retracted locked out position;

FIG. 12 is a side perspective view from the distal end of an alternate embodiment of the knife carrier of the reload assembly shown in FIG. 2;

FIG. 13 is a side perspective view of a proximal portion of the knife carrier shown in FIG. 12 with lockout members removed from a body of the knife carrier;

FIG. 14 is side perspective exploded view from the distal end of another exemplary embodiment of a reload assembly of the stapling device shown in FIG. 1;

FIG. 15 is a side perspective view from the proximal end of a lockout member of the reload assembly shown in FIG. 14;

FIG. 16 is a side perspective view from the distal end of the lockout member of the reload assembly shown in FIG. 14;

FIG. 17 is an enlarged view of the indicated area of detail shown in FIG. 14;

FIG. 18 is a side perspective view from the distal end of the lockout member shown in FIG. 15 secured to a bushing of a shell housing of the reload assembly shown in FIG. 14;

FIG. 19 is a side perspective view from the proximal end of the lockout member shown in FIG. 15 secured to the bushing of the shell housing of the reload assembly shown in FIG. 14;

FIG. 20 is an enlarged view of the indicated area of detail shown in FIG. 19;

FIG. 21 is an enlarged view of the indicated area of detail shown in FIG. 14;

FIG. 22 is an enlarged view of a proximal portion of a knife carrier of the reload assembly shown in FIG. 14;

FIG. 23 is an enlarged view of the indicated area of detail shown in FIG. 14;

FIG. 24 is a side perspective view of the reload assembly shown in FIG. 14 assembled with a shell housing shown in phantom and the staple actuator and knife carrier in retracted positions;

FIG. 25 is an enlarged view of the indicated area of detail shown in FIG. 23;

FIG. 26 is a cross-sectional view taken along section line 26-26 of FIG. 4 with the reload assembly in a pre-fired state;

FIG. 27 is an enlarged view of the indicated area of detail shown in FIG. 26;

FIG. 28 is a side cross-sectional view taken through the bushing and the knife carrier of the reload assembly shown in FIG. 14 and through a knife carrier driver of the stapling device shown in FIG. 1 with the knife carrier driver and knife carrier in retracted positions;

FIG. 29 is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver and knife carrier in retracted positions and the lockout member in a latched position;

FIG. 30 is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver partially advanced into engagement with the knife carrier and the locking member and the locking member being biased towards an unlatched position;

FIG. 31 is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver advanced into engagement with the knife carrier and the locking member biased to the unlatched position;

FIG. 32 is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver coupled to the knife carrier and the locking member biased to the unlatched position as the knife carrier driver and knife carrier move together towards an advanced position;

FIG. 33 is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver coupled to the knife carrier and the locking member retained in the unlatched position as the knife carrier driver and knife carrier move together towards the advanced position to cut tissue;

FIG. 33A is an enlarged view of the indicated area of detail shown in FIG. 28 with the knife carrier driver returned to its retracted position after firing uncoupled from the knife carrier and the locking member returned to the latched position;

FIG. 34 is side perspective view of another exemplary embodiment of a reload assembly of the stapling device shown in FIG. 1;

FIG. 35 is a cross-sectional view taken along section line 35-35 of FIG. 34 with the reload assembly in a pre-fired state;

FIG. 36 is a side perspective view of a locking member of the reload assembly shown in FIG. 34;

FIG. 37 is an enlarged view of the indicated area of detail shown in FIG. 34;

FIG. 38 is an enlarged view of the indicated area of detail shown in FIG. 35 with the knife carrier driver and knife carrier in retracted positions and the locking member in a latched position;

FIG. 39 is an enlarged view of the indicated area of detail shown in FIG. 35 with the knife carrier driver advanced into engagement with the knife carrier and the locking member as the locking member is urged from the latched position;

FIG. 40 is an enlarged view of the indicated area of detail shown in FIG. 35 with the knife carrier driver coupled to the knife carrier and the locking member retained in its unlatched position;

FIG. 41 is an enlarged view of the indicated area of detail shown in FIG. 35 with the knife carrier driver coupled to the knife carrier and the locking member retained in its unlatched state as the knife carrier driver and knife carrier are moved towards their advanced positions to cut tissue; and

FIG. 42 is an enlarged view of the indicated area of detail shown in FIG. 35 with the knife carrier driver returned to its retracted position after firing of the stapling device, with the knife carrier driver uncoupled from the knife carrier and the locking member in its latched state.

DETAILED DESCRIPTION

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.

FIGS. 1 and 2 illustrate a circular stapling device 10 including an exemplary embodiment of the disclosed reload assembly shown generally as reload assembly 100. The stapling device 10 includes a handle assembly 12, an elongate body or adaptor assembly 14, the reload assembly 100, and an anvil assembly 18 that is supported for movement in relation to the reload assembly 100 between spaced and approximated positions as is known in the art. In embodiments, the reload assembly 100 includes a proximal portion 102 that is releasably coupled to a distal portion 14a of the elongate body 14. In some embodiments, the handle assembly 12 includes a stationary grip 22 that supports actuation buttons 24 for controlling operation of various functions of the stapling device 10 including approximation of the reload and anvil assemblies 100 and 18, respectively, firing of staples from the reload assembly 100, and cutting or coring of tissue.

The stapling device 10 is illustrated as an electrically powered stapling device including an electrically powered handle assembly 12 that may support one or more batteries (not shown). The elongate body 14 is in the form of an adaptor assembly that translates power from the handle assembly 12 to the reload and anvil assemblies 100, 18, respectively. Examples of electrically powered stapling devices can be found in U.S. Pat. Nos. 9,055,943, 9,023,014, and U.S. Publication Nos. 2018/0125495, and 2017/0340351. Alternately, it is envisioned that the reload assembly could also be incorporated into a manually powered stapling device such as disclosed in U.S. Pat. No. 7,303,106 (the '106 Patent) or a stapling device that is configured for use with a robotic system such as disclosed in U.S. Pat. No. 9,962,159 that does not include a handle assembly.

FIGS. 2 and 3 illustrate the reload assembly 100 which includes a shell housing 110, a staple actuator 112, a staple pushing member 112a, a knife carrier 114, an annular knife 116 supported on the knife carrier 114, a staple cartridge 118, and a plurality of staples 120 supported within the staple cartridge 118. The staple cartridge 118 is annular and defines annular rows of staple pockets 124. Each of the staple pockets 124 supports one staple of the plurality of staples 120. The staple actuator 112 and the staple pushing member 112a together define a longitudinal through bore 132 (FIG. 8). The staple actuator 112 has a distal portion that abuts a proximal portion of the staple pushing member 112a such that distal movement of the staple actuator 112 within the shell housing 110 causes distal movement of the staple pushing member 112a within the shell housing 110. The staple pushing member 112a of the reload assembly 100 has a plurality of fingers 134. Each of the plurality of fingers 134 is received within a respective one of the staple pockets 124 of the staple cartridge 118 and is movable through the respective staple pocket 124 to eject the staples 120 from the staple pockets 124 when the staple pushing member 112a is moved from a retracted position to an advanced position within the shell housing 110.

The shell housing 110 includes an outer housing portion 140 and an inner housing portion 142 that are spaced from each other to define an annular cavity 144 (FIG. 3) between the outer and inner housing portions 140 and 142. The staple actuator 112 and the staple pushing member 112a are movable within the annular cavity 144 of the shell housing 110 from retracted positions to advanced positions to eject the staples 120 from the staple cartridge 118.

The annular knife 116 is supported about an outer surface of the knife carrier 114, defines a cylindrical cavity 117, and includes a distal cutting edge 117a. In embodiments, the annular knife 116 includes inwardly extending tangs 117b that are received within pockets 114a defined in an outer surface of the knife carrier 114 to secure the annular knife 116 to the knife carrier 114. The knife carrier 114 and annular knife 116 are positioned within the through bore 132 of the staple actuator 112 and are movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge 118.

The inner housing portion 142 of the shell housing 110 defines a through bore 150 (FIG. 3) that receives an anvil shaft (not shown) of the anvil assembly 18. For a more detailed description of an exemplary anvil assembly 18, see, e.g., the '106 Patent. The through bore 150 has a proximal portion that receives a bushing 152 (FIG. 3) that defines a through bore 150a that is coaxial and forms an extension of the through bore 150 of the inner housing portion 142. In embodiments, the bushing 152 is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion 142 of the shell housing 110 and includes an annular flange 152a.

The shell housing 110 includes a proximal portion 158 (FIG. 3) that supports a coupling mechanism 160 (FIG. 2) that is operable to releasably couple the reload assembly 100 to the adaptor assembly 14 of the stapling device 10 (FIG. 1). The coupling mechanism 160 allows for removal and replacement of the reload assembly 100 to facilitate reuse of the stapling device 10. The coupling mechanism 160 includes a retaining member 162 and a coupling member 164. The coupling member 164 is received about the proximal portion 158 (FIG. 3) of the shell housing 110 and is configured to engage the distal portion 14a (FIG. 1) of the adaptor assembly 14 to couple the reload assembly 100 to the adaptor assembly 14. It is envisioned that other coupling mechanisms can be used to secure the reload assembly 100 to the adaptor assembly 14. Alternately, the reload assembly 100 can be non-removably secured to the adaptor assembly 14.

The reload assembly 100 may include an e-prom holder 170 (FIG. 3) that is supported on the shell housing 110 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 14 to provide information to the adaptor assembly 14 and the handle assembly 12 regarding characteristics of the reload assembly 10. In some embodiments, the e-prom holder 70, may define a cylindrical collar that is received about a distal portion of the bushing 52.

FIGS. 3-6 illustrate the knife carrier 114 which includes a plurality of spaced resilient longitudinal body portions 173 that are spaced from each other and together define a central bore 172. The central bore 172 of the knife carrier 114 receives the inner housing portion 142 of the shell housing 110 such that the knife carrier 114 is movable about the inner housing portion 142 of the shell housing 110 between a retracted position (FIG. 8) and an advanced position (FIG. 9). The longitudinal body portions 173 of the knife carrier 114 define slots 176 that receive guide portions (not shown) of the shell housing 110 to limit the knife carrier 114 to longitudinal movement within the shell housing 110. In embodiments, the knife carrier 114 includes hook members 178 that are positioned to engage the staple actuator 112 to move the staple actuator 112 from its retracted position to its advanced position. The hook members 178 extend radially outwardly from the knife carrier 114 towards the staple actuator 112 within the annular cavity 144 (FIG. 3) of the shell housing 110. Each of the hook members 178 includes an engagement surface 178a and supports a locking member 180. In embodiments, the locking members 180 are positioned distally of the engagement surfaces 178a of the hook members 178 and extend outwardly and distally from the knife carrier 114 towards the staple actuator 112 at an acute angle. The locking members 180 may be formed of a resilient material that can be deformed inwardly via engagement with staple actuator 112 towards an outer surface of the knife carrier 114 but is sufficiently rigid to prevent readvancement of the knife carrier 114 as described below.

FIG. 7 illustrates the staple actuator 112 which includes a body 182 that is also received about the inner housing portion 142 (FIG. 3) of the shell housing 110 and is movable from a retracted position (FIG. 8) to an advanced position (FIG. 9) in response to movement of the knife carrier 114 from its retracted position to its advanced position. The body 182 defines a plurality of guide slots 182a and at least one stop surface 184. In some embodiments, the at least one stop surface 184 is positioned at a distal end of a channel 186 formed in the body 182. The channel 186 is positioned to receive the hook members 178. The guide slots 182a of the staple actuator 112 receive the guide members (not shown) of the shell housing 110 to limit the staple actuator 112 to longitudinal movement within the shell housing 110. The at least one stop surface 184 of the staple actuator 112 is longitudinally aligned with the engagement surfaces 178a of the hook members 178 (FIG. 4) of the knife carrier 114 such that advancement of the knife carrier 114 within the through bore 132 of the staple actuator 112 causes the engagement surfaces 178a of the hook members 178 of the knife carrier 112 to engage the at least one stop surface 184 of the staple actuator 112 to advance the staple actuator 112 within the shell housing 110 from its retraced position to its advanced position.

FIG. 8 illustrates the reload assembly 100 in a pre-fired condition with the knife carrier 114 and staple actuator 112 of the reload assembly 100 (FIG. 3) in retracted positions and the locking member 180 in an unlatched position located distally of the at least one stop surface 184 of the staple actuator 112. When the knife carrier 114 and the staple actuator 112 are in pre-fired retracted positions, the engagement surface 178a of each of the hook members 178 is aligned with and spaced proximally of the respective stop surface 184 of the staple actuator 112 and each of the locking members 180 is positioned distally of a respective stop surface 184 and is in an undeformed state.

FIG. 9 illustrates the reload assembly 100 as the staple actuator 112 and the knife carrier 114 are moved to their advanced positions. As the knife carrier 114 is moved distally within the shell housing 110 to its advanced position by a knife carrier driver (not shown) of the stapling device 10 (FIG. 1) in the direction indicated by arrows “A”, the engagement surfaces 178a of the hook members 178 engage the stop surfaces 184 of the staple actuator 112 such that the staple actuator 112 is moved distally with the knife carrier 114 in the direction indicated by arrows “B”. As the staple actuator 112 moves distally within the shell housing 110, the staple pushing member 112a is moved distally in the direction indicated by arrows “C” to advance the plurality of fingers 134 of the staple pushing member 112a through the staple pockets 124 of the staple cartridge 118 to eject the staples 120 from the staple cartridge 118 into the anvil assembly 18. As illustrated, the annular knife 116 which is secured to the knife carrier 114 is moved distally with the knife carrier 114 in the direction indicated by arrows “D” to cut tissue.

FIGS. 10 and 11 illustrate the reload assembly 100 as the knife carrier 114 is moved from its advanced position to its retracted position after the reload assembly is fired. When the knife carrier 114 is moved proximally in the direction indicated by arrows “E” towards its retracted position, the annular knife 116 is also moved proximally to a position located within the shell housing 110. In this position, a clinician is protected from inadvertent injury caused by the cutting edge 117a of the annular knife 116. As the knife carrier 114 and annular knife 116 are moved proximally within the shell housing 110, the staple actuator 112 remains in an advanced position within the shell housing 110. As the knife carrier 114 moves proximally in relation to the staple actuator 112, each of the locking members 180 engages a portion of the staple actuator 112 that defines a respective stop surface 184 such that the locking members 180 are deformed inwardly towards the outer surface of the knife carrier 114 in the direction indicated by arrow “F” in FIG. 10. In their deformed state, the locking members 180 pass inwardly and move proximally beyond the respective stop surfaces 184 (FIG. 11). When the locking members 180 move proximally past the respective stop surfaces 184, the locking members 180 spring outwardly to their undeformed state in the direction indicated by arrow “G” in FIG. 11 to positions aligned with the respective stop surfaces 184. In this position, the locking members 180 prevent readvancement of the knife carrier 112 to retain the annular knife 116 within the shell housing 110 of the reload assembly 100.

The locking members 180 may be provided in a variety of different configurations and formed of a variety of different materials. In addition, the locking members 180 may be formed integrally with the knife carrier 114 or formed separately from the knife carrier 114 and secured to the knife carrier 114 using any known fastening technique. For example as illustrated in FIGS. 3-11, the locking member 180 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 190 formed in the knife carrier 114 in cantilevered fashion. Alternately, other materials and configurations may be used to form the locking member 180. In one alternate embodiment shown in FIGS. 12 and 13, each of the locking members 180′ is formed from a resilient wire. In embodiments, the resilient wire 180′ has a circular cross-sectional shape and is received within a recess 190′ formed in the knife carrier 114 in cantilevered fashion. Alternately other cross-sectional shapes are envisioned.

FIGS. 14-33A illustrate another exemplary embodiment of the disclosed reload assembly shown generally as reload assembly 200. FIG. 14 illustrates the reload assembly 200 which can be used with the stapling device 10 (FIG. 1) and includes a shell housing 210, a staple actuator 212, a staple pushing member 212a, a knife carrier 214, an annular knife 216 supported on the knife carrier 214, a staple cartridge 218, and a plurality of staples 220 supported within the staple cartridge 218. The adaptor assembly 14 (FIG. 1) includes a knife carrier driver 215 that interacts with the knife carrier 214 to move the knife carrier 214 within the shell housing 210. The staple cartridge 218 is annular and defines annular rows of staple pockets 224. Each of the staple pockets 224 supports one staple of the plurality of staples 220. The staple actuator 212 and the staple pushing member 212a together define a longitudinal through bore 232 (FIG. 26). The staple actuator 212 has a distal portion that abuts a proximal portion of the staple pushing member 212a such that distal movement of the staple actuator 212 within the shell housing 210 causes distal movement of the staple pushing member 212a within the shell housing 210. The staple pushing member 212a of the reload assembly 200 has a plurality of fingers 234. Each of the plurality of fingers 234 is received within a respective one of the staple pockets 224 of the staple cartridge 218 and is movable through the respective staple pocket 224 to eject a staple 220 from the respective staple pocket 224 when the staple pushing member 212a is moved from a retracted position to an advanced position within the shell housing 210.

The shell housing 210 includes an outer housing portion 240 and an inner housing portion 242 that are spaced from each other to define an annular cavity 244 between the outer and inner housing portions 240 and 242. The staple actuator 212 and the staple pushing member 212a are movable within the annular cavity 244 of the shell housing 210 from a retracted position to an advanced position to eject the staples 220 from the staple cartridge 218.

The annular knife 216 is supported about an outer surface of the knife carrier 214, defines a cylindrical cavity 217, and includes a distal cutting edge 217a. The knife carrier 214 and annular knife 216 are positioned within the through bore 232 of the staple actuator 212 and movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge 218.

The inner housing portion 242 of the shell housing 210 defines a through bore 250 that receives an anvil shaft (not shown) of the anvil assembly 18 (FIG. 1). For a more detailed description of an exemplary anvil assembly 18, see, e.g., the '106 Patent. The through bore 250 has a proximal portion that receives a bushing 252 that defines a through bore 250a that is coaxial and forms an extension of the through bore 250 of the inner housing portion 242. In embodiments, the bushing 252 is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion 242 of the shell housing 210 and includes an annular flange 252a. The annular flange 252 includes a protrusion 253.

The shell housing 210 includes a proximal portion 258 that supports a coupling mechanism 260 that is operable to releasably couple the reload assembly 200 to the adaptor assembly 14 of the stapling device 10 (FIG. 1). The coupling mechanism 260 allows for removal and replacement of the reload assembly 200 to facilitate reuse of the stapling device 10. The coupling mechanism 260 includes a retaining member 262 and a coupling member 264. The coupling member 264 is received about the proximal portion 258 of the shell housing 210 and is configured to engage the distal portion 14a (FIG. 1) of the adaptor assembly 14 to couple the reload assembly 200 to the adaptor assembly 14. It is envisioned that other coupling mechanisms can be used to secure the reload assembly 200 to the adaptor assembly 14. Alternately, the reload assembly 200 can be non-removably secured to the adaptor assembly 14.

The reload assembly 200 may include an e-prom holder 270 that is supported on the shell housing 210 and is configured to support an e-prom (not shown). As is known in the art, an e-prom communicates with the adaptor assembly 14 (FIG. 1) to provide information to the adaptor assembly 14 and the handle assembly 12 (FIG. 1) regarding characteristics of the reload assembly 10. In some embodiments, the e-prom holder 270 can be received about a distal portion of the bushing 52.

The knife carrier 214 includes a plurality of resilient longitudinal body portions 273 that are spaced from each other and together define a central bore 272. The central bore 272 of the knife carrier 214 receives the inner housing portion 242 of the shell housing 210 such that the knife carrier 214 is movable about the inner housing portion 242 of the shell housing 210 between a retracted position and an advanced position. The longitudinal body portions 273 of the knife carrier 214 are resilient and spaced from each other to define slots 276 that receive guide portions (not shown) of the shell housing 210 to limit the knife carrier 214 to longitudinal movement within the shell housing 210.

The staple actuator 212 includes a body that is also received about the inner housing portion 242 of the shell housing 210 and is movable within the shell housing 210 from a retracted position to an advanced position. The body defines a plurality of guide slots 281 that receive the guide members (not shown) of the shell housing 210 to limit the staple actuator 212 to longitudinal movement within the shell housing 210.

FIGS. 14-20 illustrate a locking member 280 of the reload assembly 200 that includes a body 282 having an annular ring 284 and a lockout latch 286. The annular ring 284 is received about a proximal portion of the bushing 252 and is positioned in abutting relation to the flange 252a to secure the locking member 280 to the bushing 252 (FIG. 14). The annular ring 284 defines a cutout 288 which may be rectangular in shape and receives the protrusion 253 formed on the bushing 252 to prevent rotation of the locking member 280 in relation to the bushing 252 (FIG. 20). In embodiments, the annular ring 280 of the locking member 280 may include a slot 298 to allow for radial flexing of the annular ring 280 to facilitate placement of the locking member 280 in a friction fit manner about the bushing 252.

The lockout latch 286 is formed of a resilient material and extends in cantilevered fashion from the annular ring 284. In embodiments, the lockout latch 286 is integrally formed with the annular ring 280 of the locking member. Alternately, the lockout latch 286 can be pivotably secured to the annular ring 280 in cantilevered fashion using, e.g., a hinge mechanism (not shown). The lockout latch 286 includes a first tab 290 that has an angled proximally facing surface 292 and a second tab 294 that has a substantially perpendicular proximally facing surface 296. In embodiments, the first tab 290 has a generally triangular shape and the second tab 294 has a generally rectangular shape. Alternately, other configurations are envisioned. The lockout latch 286 is movable from an unbiased position in which the lockout latch 286 is spaced outwardly of and extends along an outer surface of the bushing 252 to a biased position in which the lockout latch 286 is biased inwardly towards the outer surface of the bushing 252.

FIGS. 21-23 illustrate a proximal portion of the longitudinal body portions 273 of the knife carrier 214. Each of the longitudinal body portions 273 of the knife carrier 214 defines an annular recess 300 and a tapered surface 302 that is positioned proximally of the annular recess 300. The knife carrier driver 215 (FIG. 23) of the adaptor assembly 14 includes an inner annular rib 306 that is received within the annular recesses 300 of the longitudinal body portions 273 to couple the knife carrier driver 215 to the knife carrier 214 when the stapling device 10 (FIG. 1) is actuated to fire staples 220 (FIG. 14) from the reload assembly 200. One of the longitudinal body portions 273 also defines a notch 310 that receives the second tab 294 of the locking member 280 when the knife carrier 214 is in a retracted position within the shell housing 210 to obstruct distal movement of the knife carrier within the shell housing 210.

FIGS. 24-29 illustrate the reload assembly 200 in a pre-fired state with the knife carrier 214, the knife driver 215, the staple actuator 212, and the staple pushing member 212a in their retracted positions. In the pre-fired state, the distal end of the knife driver 215 is positioned adjacent to a proximal end of the knife carrier 214 and adjacent to the lockout latch 286 of the locking member 280. In this position, the inner annular rib 306 at the distal end portion of the knife driver 215 is spaced proximally of the annular recesses 300 formed in the longitudinal body portions 273 of the knife carrier 214. In addition, the lockout latch 286 is in its undeformed state with the first tab 290 of the lockout latch 286 located adjacent to the distal end of the knife driver 215 and the second tab 294 received within the notch 310 formed in the longitudinal body portion 273 of the knife carrier 214. When the second tab 294 positioned within the notch 310, the proximally facing surface 296 of the second tab 294 obstructs advancement of the knife carrier 214 within the shell housing 210.

FIGS. 30-33 illustrate the reload assembly 200 as the knife driver 215 is moved towards its advanced position to move the knife carrier 214 and the annular knife 216 toward their advanced positions. When the knife driver 215 is advanced within the shell housing 210 in the direction indicated by arrow “H” in FIG. 30, the distal end portion of the knife driver 215 engages the tapered surface 302 at the proximal end portion of each of the longitudinal body portions 273 of the knife carrier 214 to urge the longitudinal body portions 273 inwardly in the direction indicated by arrow “I” in FIG. 30. This allows the inner annular rib 306 of the knife driver 215 to pass into the annular recesses 300 of the longitudinal body portions 273 of the knife carrier 214 to couple the distal end portion of the knife driver 215 to the proximal end portion of the knife carrier 214.

As the knife driver 215 continues to advance within the shell housing 210 in the direction indicated by arrow “H” in FIG. 31, the distal end portion of the knife driver 215 also engages the angled proximally facing surface 292 of the first tab 290 to urge the lockout latch 286 inwardly in the direction indicated by arrow “J” towards its deformed state. As the lockout latch 286 moves inwardly towards the bushing 252 to its deformed state, the second tab 294 of the lockout latch 286 is removed from the notch 310 formed in the proximal end of the respective longitudinal body portion 273 of the knife carrier 214. In this position, the second tab 294 does not obstruct advancement of the knife carrier 214 within the shell housing 210. As the knife driver 215 advances within the shell housing 210, engagement between the knife driver 215 and the first tab 290 retains the lockout latch 286 in its deformed state with the second tab 294 removed from the notch 310 to allow the knife carrier 214 and the knife driver 215 to move to their advanced positions to advance the annular knife 216 to its advanced position extending from the shell housing 210 to cut tissue.

FIG. 33A illustrates the reload assembly 200 as the knife carrier 214 and the knife driver 215 are moved from their advanced positions back to their retracted positions in the direction indicated by arrows “K”. This movement retracts the annular knife 216 into the shell housing 210. When the knife carrier 214 reaches its retracted position and cannot move further proximally, the longitudinal body portions 273 are forced inwardly by the inner annular rib 306 of the knife driver 215 such that the inner annular rib 306 is removed from the annular recesses 300 of the longitudinal body portions 273 of the knife driver 214 to uncouple the knife driver 215 from the knife carrier 214. When the notch 310 in the longitudinal body portion 273 of the knife carrier 214 becomes aligned with the second tab 294 of the lockout latch 286 of the locking member 280, the lockout latch 286 pivots in the direction indicated by arrow “L” in FIG. 33A to reposition the second tab 294 within the notch 310. Once again, this obstructs advancement of the knife carrier 214 to prevent readvancement of the annular knife 216 from within the shell housing 210.

FIGS. 34-42 illustrate another exemplary embodiment of the disclosed reload assembly shown generally as reload assembly 400 which can be used with the stapling device 10 (FIG. 1). FIGS. 34 and 35 illustrate another exemplary embodiment of the reload assembly shown generally as reload assembly 400. Reload assembly 400 includes a shell housing 410, a staple actuator 412, a staple pushing member 412a, a knife carrier 414, an annular knife 416 supported on the knife carrier 414, a staple cartridge 418, and a plurality of staples 420 supported within the staple cartridge 418. The adaptor assembly 14 (FIG. 1) includes a knife carrier driver 415 (FIG. 35) that interacts with the knife carrier 414 to move the knife carrier 414 from a retracted position to an advanced position within the shell housing 410 as described in detail below. The staple cartridge 418 is annular and defines annular rows of staple pockets 424. Each of the staple pockets 424 supports one of the plurality of staples 420. The staple actuator 412 and the staple pushing member 412a together define a longitudinal through bore 432 (FIG. 35). The staple actuator 412 has a distal portion that abuts a proximal portion of the staple pushing member 412a such that distal movement of the staple actuator 412 within the shell housing 410 causes distal movement of the staple pushing member 412a within the shell housing 410. The staple pushing member 412a of the reload assembly 400 has a plurality of fingers 434. Each of the plurality of fingers 434 is received within a respective one of the staple pockets 424 of the staple cartridge 418 and is movable through the respective staple pocket 424 to eject a staple 420 from a respective pocket 424 of the staple cartridge 418 when the staple pushing member 412a is moved from a retracted position to an advanced position within the shell housing 410.

The shell housing 410 includes an outer housing portion 440 and an inner housing portion 442 that are spaced from each other to define an annular cavity 444 (FIG. 35) between the outer and inner housing portions 440 and 442. The staple actuator 412 and the staple pushing member 412a are movable within the annular cavity 444 of the shell housing 410 from a retracted position to an advanced position to eject the staples 420 from the staple cartridge 418.

The annular knife 416 is supported about an outer surface of the knife carrier 414, defines a cylindrical cavity 417, and includes an annular cutting edge 417a. The knife carrier 414 and annular knife 416 are positioned within the through bore 432 of the staple actuator 412 and are movable from retracted positions to advanced positions to cut tissue positioned radially inward of the staple cartridge 418.

The inner housing portion 442 of the shell housing 410 defines a through bore 450 that receives an anvil shaft (not shown) of the anvil assembly 18 (FIG. 1). The through bore 450 has a proximal portion that receives a bushing 452 that defines a through bore 450a that is coaxial with and forms an extension of the through bore 450 of the inner housing portion 442. In embodiments, the bushing 452 is formed of a high strength material, e.g., metal, to provide added strength to the inner housing portion 442 of the shell housing 410 and includes an annular flange 452a. The shell housing 410 includes a proximal portion 458 that supports a coupling mechanism 460 that is operable to releasably couple the reload assembly 400 to the adaptor assembly 14 of the stapling device 10 (FIG. 1). The coupling mechanism 460 allows for removal and replacement of the reload assembly 400 to facilitate reuse of the stapling device 10 (FIG. 1). The coupling mechanism 460 includes a retaining member 462 and a coupling member 464. The coupling member 464 is received about the proximal portion 458 of the shell housing 410 and is configured to engage the distal portion 14a (FIG. 1) of the adaptor assembly 14 to couple the reload assembly 400 to the adaptor assembly 14. It is envisioned that other coupling mechanisms can be used to secure the reload assembly 400 to the adaptor assembly 14. Alternately, the reload assembly 400 can be fixedly secured to the adaptor assembly 14.

The knife carrier 414 includes a plurality of spaced longitudinal body portions 473 that are spaced from each other and together define a central bore 472 (FIG. 35). The central bore 472 of the knife carrier 414 receives the inner housing portion 442 of the shell housing 410 such that the knife carrier 414 is movable about the inner housing portion 442 of the shell housing 410 between a retracted position and an advanced position. The longitudinal body portions 473 of the knife carrier 414 are spaced from each other to define slots 476 that receive guide portions (not shown) of the shell housing 410 to limit the knife carrier 414 to longitudinal movement within the shell housing 410.

The staple actuator 412 includes a body that is also received about the inner housing portion 442 of the shell housing 410 and is movable within the shell housing 410 from a retracted position to an advanced position. The body of the staple actuator 412 defines a plurality of guide slots (not shown) that receive the guide members (not shown) of the shell housing 410 to limit the staple actuator 412 to longitudinal movement within the shell housing 410.

FIGS. 36 and 37 illustrate a locking member 480 of the reload assembly 400 that includes a body 482 having an annular ring 484 and a lockout latch 486. The annular ring 484 is received about a proximal portion of the bushing 452 (FIG. 35) and is positioned in abutting relation to the flange 452a to secure the locking member 480 to the bushing 452 (FIG. 35). The annular ring 484 of the locking member 480 may include a slot 498 to allow for flexing of the annular ring 480 to facilitate placement of the locking member 480 in a friction fit manner about the bushing 452.

The lockout latch 486 is formed of a resilient material and extends from the annular ring 484. In embodiments, the lockout latch 486 is integrally formed with the annular ring 484 of the locking member 480 and includes a first longitudinal portion 488, a transverse portion 490, and a second longitudinal portion 492. The first longitudinal portion 488 has a first end coupled to the annular ring 484 and extends distally from the annular ring 484. The transverse portion 490 of the lockout latch 486 extends from a second end of the first longitudinal portion 488 radially outward from the bushing 452. The second longitudinal portion 492 extends proximally from the transverse portion 490 and has a proximal end portion that supports a latch member 494. In embodiments, the latch member 494 includes a cam surface 494a that is angled radially outwardly from the second longitudinal portion 492 and defines an axis that is transverse to axes defined by the first and second longitudinal portions 488 and 492 of the locking member 480 and transverse to the transverse portion 490. In embodiments, the locking member 480 can be of integral construction. Alternately, the lockout latch 486 can be pivotably secured to the annular ring 480 using any of a variety of fastening techniques.

In embodiments, the first and second longitudinal portions 488 and 492 are aligned with one of the longitudinal slots 476 defined between the longitudinal body portions 473 of the knife carrier 414 and the transverse portion 490 extends through the respective slot 476. In this configuration, the first longitudinal portion 488 of the locking member 480 is positioned within the knife carrier 414 and the second longitudinal portion 492 is positioned along an outer surface of the knife carrier 414 and supports the latch member 494 in cantilevered fashion.

FIGS. 37 and 38 illustrate a proximal portion of the longitudinal body portions 473 of the knife carrier 414. Each of the longitudinal body portions 473 of the knife carrier 414 defines an annular recess 500 and includes a tapered proximal surface 502 that is positioned proximally of the annular recess 500. The annular recess 500 is defined in part by a proximal wall 500a. The knife driver 415 (FIG. 38) of the adaptor assembly 14 (FIG. 1) includes an inner annular rib 506 that is received within the annular recesses 500 of the longitudinal body portions 473 to couple the knife driver 415 to the knife carrier 414 when the stapling device 10 (FIG. 1) is actuated to fire staples (not shown) from the reload assembly 400. The latch member 494 is received within the annular recess 500 (FIG. 37) of the knife carrier 414 when the knife carrier 414 is in a pre-fired retracted position to obstruct distal movement of the knife carrier 414 within the shell housing 410 (FIG. 34). More specifically, the latch member 494 is positioned to engage the proximal wall 500a defining the annular recess 500 in the knife carrier 414 to prevent advancement of the knife carrier 414 within the shell housing 410.

FIGS. 35 and 38 illustrate the reload assembly 400 in the pre-fired state with the knife carrier 414, the knife driver 415, the staple actuator 412, and the staple pushing member 412a in their retracted positions. In the pre-fired state, the distal end of the knife driver 415 is positioned adjacent to a proximal end of the knife carrier 414 and adjacent to the lockout latch 486 of the locking member 480. In this position, the inner annular rib 506 at the distal end portion of the knife driver 415 is spaced proximally of the annular recesses 500 formed in the longitudinal body portions 473 of the knife carrier 414. In addition, the lockout latch 486 is in its undeformed state with the latch member 494 of the lockout latch 486 received within the annular recess 500 of the knife carrier 414. In this position, the latch member 494 is aligned with the proximal wall 500a defining the annular recess 500 to prevent advancement of the knife carrier 414 from its retracted position toward its advanced position. In its retracted position, the annular knife 416 including the cutting edge 417a is shielded within the shell housing 410.

FIGS. 39-41 illustrate the reload assembly 400 as the knife driver 415 is moved from its retracted position towards its advanced position to move the knife carrier 414 and the annular knife 416 toward their advanced positions. When the knife driver 415 is advanced within the shell housing 410 in the direction indicated by arrow “M” in FIG. 39, the distal end portion of the knife driver 415 engages the tapered surface 502 at the proximal end portion of each of the longitudinal body portions 473 of the knife carrier 414 to urge the longitudinal body portions 473 inwardly in the direction indicated by arrow “N” in FIG. 39. This allows the inner annular rib 506 of the knife driver 515 to pass into the annular recesses 500 of the longitudinal body portions 473 of the knife carrier 414 to couple the distal end portion of the knife driver 415 to the proximal end portion of the knife carrier 414 (FIG. 41).

As the knife driver 415 continues to advance within the shell housing 410 in the direction indicated by arrow “M” in FIGS. 39 and 40, the distal end portion of the knife driver 415 engages the cam surface 494a of the of the latch member 494 to urge the lockout latch 486 outwardly in the direction indicated by arrows “O” towards its deformed state. As the lockout latch 486 moves outwardly away from the bushing 452 to its deformed state, the latch member 494 of the lockout latch 486 is removed from the annular recess 500 formed in the proximal end of the longitudinal body portion 473 of the knife carrier 514 such that the latch member 494 does not obstruct advancement of the knife carrier 414 within the shell housing 410. As such, the knife carrier 414 and the annular knife 416 can be advanced to cut tissue.

FIG. 42 illustrates the reload assembly 400 as the knife carrier 414 and the knife driver 415 are moved from their advanced positions back to their retracted positions in the direction indicated by arrow “P”. This movement retracts the annular knife 416 (FIG. 35) into the shell housing 410. When the knife carrier 414 reaches its retracted position and cannot move further proximally through the shell housing 410 (FIG. 35), the longitudinal body portions 473 are forced inwardly by the inner annular rib 506 of the knife driver 415 such that the inner annular rib 506 is removed from the annular recesses 500 of the longitudinal body portions 473 of the knife driver 414 to uncouple the knife driver 415 from the knife carrier 414. In its retracted position, the annular recess 500 of the knife carrier 414 is aligned with the latch member 494 of the lockout latch 486 of the lockout member 480 such that the lockout latch 486 returns to its undeformed state with the latch member 480 received within the annular recess 500 of adjacent longitudinal body portions 473. Once again, the latch member 480 obstructs advancement of the knife carrier 414 to prevent readvancement of the annular knife 216 from within the shell housing 410.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.

Claims

1. A surgical stapling device comprising: an adaptor assembly having a proximal end portion and a distal end portion and including a knife driver, the knife driver being movable between a retracted position and an advance position; anda reload assembly supported on the distal end portion of the adaptor assembly, the reload assembly including: a shell housing including an outer housing portion and an inner housing portion, the inner and outer housing portions defining an annular cavity;a staple cartridge supported on the shell housing and including a plurality of staples;a staple pusher supported within the annular cavity and movable from a retracted position to an advanced position to eject staples from the staple cartridge;a staple actuator supported within the annular cavity in a position to engage the staple pusher and defining a through bore, the staple actuator movable from a retracted position to an advanced position to move the staple pusher from its retracted position to its advanced position;a knife carrier supported within the through bore and including a distal portion and a proximal portion, the knife carrier 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;a knife supported on the knife carrier; anda locking member supported on the inner housing portion and including a lockout latch, the lockout latch being 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, 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.

2. The surgical stapling device of claim 1, wherein the proximal portion of the knife carrier includes resilient longitudinal body portions, each of the resilient longitudinal body portions defining an annular recess, and the knife driver having a distal end portion including an annular rib, 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.

3. The surgical stapling device of claim 1, wherein the lockout latch supports a first tab and the knife carrier defines a notch, 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.

4. The surgical stapling device of claim 3, wherein the lockout latch includes a second tab having an angled proximally facing surface, the knife driver being 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.

5. The surgical stapling device of claim 2, wherein the proximal end portion of each of the longitudinal body portions includes a tapered surface that is positioned proximally of the annular recesses, the tapered surfaces being 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.

6. The surgical stapling device of claim 2, further including a bushing supported on the inner housing portion of the shell housing, the locking member being supported on the bushing.

7. The surgical stapling device of claim 6, wherein the bushing includes a protrusion and the locking member includes an annular ring defining a cutout, the annular ring being received about the bushing and the protrusion being received within the cutout to prevent the locking member from rotating in relation to the bushing.

8. The surgical stapling device of claim 6, wherein the locking member includes an annular ring supported on the bushing, and the lockout latch of the locking member includes a transverse portion that extends through a slot defined by the longitudinal body portions of the knife carrier and a proximally extending longitudinal portion that extends from the transverse portion in cantilevered fashion, the proximally extending longitudinal portion of the lockout latch supporting 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.

9. The surgical stapling device of claim 8, wherein the locking member includes a cam surface positioned adjacent to the latch member, the cam surface positioned to be engaged by the distal end portion of the knife driver when the knife driver is moved from its retacted position towards its advanced position to move the locking member from the undeformed state to the deformed state.

10. A reload assembly comprising: a shell housing including an outer housing portion and an inner housing portion, the inner and outer housing portions defining an annular cavity;a staple cartridge supported on the shell housing and including a plurality of staples;a staple pusher supported within the annular cavity and movable from a retracted position to an advanced position to eject staples from the staple cartridge;a staple actuator supported within the annular cavity in a position to engage the staple pusher and defining a through bore, the staple actuator movable from a retracted position to an advanced position to move the staple pusher from its retracted position to its advanced position;a knife carrier supported within the through bore and including a distal portion and a proximal portion, the knife carrier movable between a retracted position and an advanced position;a knife supported on the knife carrier and movable from a retracted position to an advanced position in response to movement of the knife carrier from its retracted position to its advanced position to cut tissue; anda locking member supported on the inner housing portion and including a lockout latch, the lockout latch being 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.

11. The surgical stapling device of claim 10, further including a bushing supported on the inner housing portion of the shell housing, the locking member being supported on the bushing.