Stapling device with cut ring biasing member

A circular stapling device includes a shell assembly and an anvil assembly. The shell assembly includes a housing, a staple cartridge supported on the housing, an annular knife supported within the housing, and a biasing member supported within the housing. The anvil assembly includes a center rod and an anvil head that supports a cut ring that is axially aligned with the annular knife. The biasing member is positioned within the housing and extends to a position distally of the annular knife when the annular knife is in the retracted position to shield the annular knife. The anvil assembly is movably supported in relation to the shell assembly between an unapproximated position and an approximated position, wherein in the approximated position, the biasing member is engaged with the cut ring and urges the cut ring in a distal direction.

BACKGROUND

1. Technical Description

The present disclosure is directed to circular stapling devices and more particularly, to a shell assembly of a circular device with structure to facilitate separation of a knife and a cut ring after firing.

2. Background of Related Art

Circular stapling devices for performing end-to-end or end-to-side anastomosis procedures are well known. Typically, circular stapling devices include a staple cartridge that supports a plurality of staples, a pusher that is movable in relation to the staple cartridge to eject the staples from the staple cartridge, an annular knife that is movable to core tissue within the anastomosis, and an anvil assembly that is positioned to deform the staples. In embodiments, the anvil includes a cut ring that provides a back stop for the annular knife.

In known stapling devices, the anvil assembly includes an anvil head that is pivotal from an operative position to a tilted position to reduce a profile of the anvil assembly for subsequent removal of the anvil assembly from a patient. In such stapling devices, the cut ring is movable in response to engagement by the annular knife from a first position that prevents movement of the anvil head from the operative position to the tilted position to a second position that allows for pivotal movement of the anvil head from the operative position to the tilted position. When the annular knife is advanced into the cut ring of the anvil assembly during firing of the stapling device, the annular knife urges the cut ring from the first position to the second position to facilitate tilting of the anvil head.

Typically, the cut ring is formed in part from a material that is softer than the annular knife such that the annular knife penetrates the cut ring during firing of the stapling device. In some instances, the annular knife sticks to the cut ring and the cut ring is moved back to its first position when the annular knife is retracted to a pre-fired position after firing. When this happens, the anvil head is prevented from moving to the tilted position after firing.

A continuing need exists in the art for an improved shell assembly for a circular stapling device that includes a simple device or mechanism that ensures separation of the annular knife and cut ring after firing of the stapling device to facilitate movement of the anvil head to the tilted position during removal of the stapling device from a patient.

SUMMARY

One aspect of the present disclosure is directed to a circular stapling device having an elongate body, a shell assembly, and an anvil assembly. The elongate body has a proximal portion and a distal portion. The shell assembly includes a housing, a staple cartridge supported on the housing, an annular knife supported within the housing, and a biasing member supported within the housing. The biasing member has a proximal portion and a distal portion. The annular knife is movable within the housing from a retracted position to an advanced position and extends from the distal portion of the housing in the advanced position. The biasing member extends to a position distally of the annular knife when the annular knife is in the retracted position. The anvil assembly includes a center rod and an anvil head that supports a cut ring that is axially aligned with the annular knife. The anvil assembly is movably supported in relation to the shell assembly between an unapproximated position and an approximated position, wherein in the approximated position, the biasing member is engaged with the cut ring and urges the cut ring in a distal direction.

Another aspect of the present disclosure is directed to a shell assembly including a housing, a staple cartridge, an annular knife, and a biasing member. The housing has a proximal portion and a distal portion and defines an annular channel. The staple cartridge is supported on the housing. The shell assembly defines a plurality of staple receiving pockets that support staples. The annular knife is supported within the housing and is movable within the housing from a retracted position to an advanced position. The annular knife extends from the distal portion of the housing when the annular knife is in the advanced position. The biasing member is supported within the annular channel of the housing and extends to a position distally of the annular knife when the annular knife is in the retracted position.

In embodiments, the biasing member is a coil spring.

In some embodiments, the shell assembly includes a pusher assembly including a pusher having a plurality of fingers, wherein the pusher is movable from a retracted position to an advanced position to eject staples from the staple cartridge.

In certain embodiments, the shall assembly includes a knife carrier that supports the annular knife and is movable from a retracted position to an advanced position within the housing, wherein the annular knife engages the cut ring when the anvil assembly and the shell assembly are in the approximated position and the annular knife is in the advanced position.

In embodiments, the annular knife includes a cutting edge that is positioned distally of the biasing member when the annular knife is in the advanced position.

In some embodiments, the biasing member is secured to the knife carrier.

In certain embodiments, the knife carrier defines a retaining groove that receives a coil of the coil spring to secure the biasing member to the knife carrier.

In embodiments, the stapling device includes a handle assembly and the elongate body extends distally from the handle assembly.

In some embodiments, the shell assembly includes a knife carrier that supports the annular knife, and the knife carrier is movable from a retracted position to an advanced position within the housing independently of the pusher.

In certain embodiments, the housing defines an annular channel, and the pusher and the knife carrier are movably supported within the annular channel.

In embodiments, the biasing member is positioned within the annular knife.

DETAILED DESCRIPTION OF EMBODIMENTS

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

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through small diameter incision or cannula. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel.

FIGS. 1-2Aillustrate an exemplary embodiment of the presently disclosed circular stapling device shown generally as stapling device10. The stapling device10includes a handle assembly12, an elongate body or adaptor assembly14, and an anvil assembly16. The adaptor assembly14includes an elongate body18and a shell assembly20. The shell assembly20has a proximal portion supported on a distal portion of the elongate body18and a distal portion that supports a staple cartridge22. The staple cartridge22defines a plurality of annular rows of staple receiving pockets24. Each of the staple receiving pockets24receives a staple26(FIG. 2A) such that the staple cartridge20supports annular rows of staples26. The anvil assembly16includes a head28and a center rod30. The anvil head28is supported on a distal end of the anvil center rod30by a pivot member32(FIG. 2A) and supports a cut ring33(FIG. 2A). The cut ring33is movable within a recess35(FIG. 2A) defined within the anvil head28from a retracted position (FIG. 2A) to an advanced position (FIG. 7.) As is known in the art, in the retracted position, the cut ring33prevents tilting of the anvil head28in relation to the center rod30, and in the advanced position, the cut ring33allows tilting of the anvil head28in relation to the center rod30. See, e.g., U.S. Pat. No. 7,303,106 (“the '106 patent”) for a detailed description of exemplary embodiments of an anvil assembly with a tiltable anvil assembly. The '106 patent is incorporated herein by reference in its entirety.

The handle assembly12is illustrated as a powered assembly and includes a stationary grip34(FIG. 1) and actuation buttons32for controlling operation of stapling device functions including approximation of the anvil and shell assemblies16,20, respectively, and firing of staples26(FIG. 2A) from the staple cartridge22of the shell assembly20. The adaptor assembly14is coupled to the handle assembly12to translate power from the handle assembly12to the anvil and shell assemblies16,20. Although the present disclosure illustrates powered handle and adaptor assemblies12,14, respectively, it is envisioned that the advantages of the present disclosure as described in detail below are also applicable to circular stapling devices having manually operated handle and adaptor assemblies. The '106 patent discloses an example of a surgical stapling device including a manually actuated handle assembly and is incorporated herein by reference in its entirety. U.S. Pat. No. 9,023,014 (“the '014 patent”) and U.S. Pat. No. 9,055,943 (“the '943 patent”) disclose examples of surgical stapling devices including exemplary powered handle and adaptor assemblies. Each of these patents is incorporated herein by reference in its entirety.

Referring toFIGS. 2-3, the shell assembly20includes a housing40having an inner housing portion42(FIG. 2A) and an outer housing portion44. The inner housing portion42defines a central through bore46. The central through bore46receives an anvil retainer (not shown) of the adaptor assembly14and the anvil center rod30when the stapling device10is approximated as is known in the art. The inner housing portion42and the outer housing portion44of the housing portion44define an annular channel48.

The shell assembly20also includes a pusher assembly50and a knife assembly52. The pusher assembly50and the knife assembly52are supported within the annular channel48of the shell housing40for movement between a retracted position (FIG. 2A) and an advanced position (FIG. 7). The pusher assembly50includes a pusher back54and a pusher56. The pusher back54includes a proximal end that is coupled to the adaptor assembly14and a distal end that is in abutting relation to the pusher56. The pusher56includes fingers58that are received within the staple receiving pockets24of the staple cartridge22and engage the staples26. When the adaptor assembly14is driven to advance the pusher assembly50within the annular channel48of the shell housing40, the fingers58of the pusher56are advanced through the staple receiving pockets24of the staple cartridge22to fire the staples26from the staple cartridge22.

Referring also toFIGS. 4-6, the knife assembly52includes a knife carrier60and an annular knife blade62. The knife carrier60includes a proximal end that is coupled to the adaptor assembly14and a distal end that supports the annular knife blade62. In embodiments, the annular knife62includes a cutting edge62a. The annular knife62is axially aligned with the cut ring33of the anvil head28of the anvil assembly16. When the adaptor assembly14is driven to advance the knife carrier60within the annular channel48of the shell housing40, the annular knife blade62is advanced into the cut ring33of the anvil assembly16. For a more detailed description of the interconnection of the adaptor assembly14and the pusher and knife assemblies50,52of a circular stapling device, see U.S. patent application Ser. No. 15/467,153 which is incorporated herein by reference in its entirety.

The knife assembly52also includes a biasing member64that is positioned on the distal portion of the knife carrier60and extends along an internal surface62a(FIG. 2A) of the knife blade62. In an unbiased state of the biasing member64, a distal end of the biasing member64is positioned distally of the distal end of the annular knife blade62(FIG. 5) to shield the end of the knife blade62from a clinician. The biasing member64is in an unbiased state when the stapling device10is in an unapproximated state (FIG. 2A.)

In embodiments, the biasing member64is a coil spring and the knife carrier60includes an annular retainer groove66(FIG. 5). The annular retainer groove66is configured to receive a coil70at a proximal end of the biasing member64to secure the biasing member64to the knife carrier60. As described above, the annular knife blade62is positioned about the biasing member64in a position to prevent separation of the coil70from the retaining groove66.

Referring toFIG. 7, when the anvil assembly16and the shell assembly20are approximated, the distal end of the biasing member64is in contact with the cut ring33. When the stapling device10is fired, the biasing member64and the annular knife62are advanced into the cut ring33to compress the biasing member64such that the distal end of the annular knife62moves distally beyond the distal end of the biasing member64and penetrates the cut ring33of the anvil assembly16. When the knife assembly52is in the advanced position within the housing40of the shell assembly20, the biasing member64is compressed between the cut ring33of the anvil assembly16and the knife carrier60to urge the knife assembly52to the retracted position and to urge the cut ring33to the advanced position. When the knife assembly52is retracted after firing of the stapling device10, the biasing member64minimizes the likelihood that the cut ring33will stick to the annular knife62and be returned to its retracted position (FIG. 2A). As discussed above, if the cut ring33returns to its first position, the anvil head28may be prevented from moving to a tilted reduced profile position after firing.