BACKGROUND

1. Technical Description

The present disclosure is directed to circular stapling devices, and more particularly, to circular stapling devices including structure to properly align an anvil assembly with a staple cartridge of a shell assembly of the circular stapling device.

2. Background of Related Art

Circular stapling devices are utilized by clinicians to apply one or more surgical fasteners, e.g., staples or two-part fasteners, to body tissue for the purpose of joining segments of body tissue together and/or for the creation of an anastomosis. Circular stapling devices generally include a cartridge or shell assembly supporting a plurality of annular rows of staples, an anvil assembly operatively associated with the cartridge assembly and having annular arrays of staple receiving pockets for providing a surface against which the plurality of annular rows of staples can be formed, and an annular blade for cutting tissue.

During a typical tissue fastening procedure, the anvil assembly of the stapling device is positioned within one segment of body tissue and the shell assembly and a body portion of the stapling device supporting the shell assembly are positioned in an adjacent segment of body tissue. The anvil assembly is then attached to the body portion of the stapling device and the stapling device is actuated to approximate the anvil assembly with the cartridge assembly and clamp the body tissue segments together.

Typically, the anvil assembly includes an anvil shaft that includes splines that mate with splines formed within a shell housing of the shell assembly to align the staple forming pockets of the anvil assembly with staple receiving pockets of the staple cartridge of the shell assembly. Misalignment of the splines often results in misalignment of the staple forming pockets of the anvil assembly and the staple receiving pockets of the shell assembly such that malformation of the staples occurs during firing of the stapling device.

A continuing need exist for a circular stapling device including more reliable alignment structure for aligning the staple forming pockets of the anvil assembly with the staple receiving pockets of the shell assembly.

SUMMARY

In one aspect of the disclosure, a surgical stapling device includes a body portion and a tool assembly supported on a distal portion of the body portion. The tool assembly includes an anvil assembly and a cartridge assembly. The body portion includes an anvil retainer having a proximal portion and a distal portion. The proximal portion of the anvil retainer supports a first longitudinal rib and the distal portion of the anvil retainer supports a second longitudinal rib. The anvil assembly of the tool assembly has an anvil shaft and an anvil head supported on a distal portion of the anvil shaft. The anvil shaft has a plurality of resilient legs defining a bore. The resilient legs flex outwardly to facilitate passage of the anvil retainer into the bore. Adjacent resilient legs of the plurality of resilient legs define longitudinal channels. At least one of the longitudinal channels defined by the resilient legs receives the second longitudinal rib to prevent rotation of the anvil shaft in relation to the anvil retainer. The shell assembly is supported on a distal portion of the body portion and includes a shell housing having an inner housing portion defining a through bore. The anvil retainer extends through the through bore. A bushing is supported within the through bore of the inner housing portion of the shell housing. The bushing defines an internal slot that receives the first longitudinal rib to prevent rotation of the anvil retainer within the through bore of the bushing.

In another aspect of the disclosure, the surgical stapling device includes a body portion, an anvil assembly, and a cartridge assembly. The body portion includes an anvil retainer, having a proximal portion supporting a first longitudinal rib and a distal portion supporting at least one second longitudinal rib. The anvil assembly has an anvil shaft and an anvil head supported on a distal portion of the anvil shaft. The anvil shaft defines a longitudinal bore and at least one longitudinal channel. The longitudinal bore is dimensioned to receive the distal portion of the anvil retainer. The second longitudinal rib is received within the at least one longitudinal channel when the distal portion of the anvil retainer is received within the longitudinal bore to prevent rotation of the anvil assembly in relation to the anvil retainer. The shell assembly is supported on a distal portion of the body portion and includes a shell housing having an inner housing portion defining a through bore. The anvil retainer extends through the through bore. A bushing defining an internal slot is supported within the through bore of the inner housing portion of the shell housing. The internal slot receives the first longitudinal rib of the anvil retainer to prevent rotation of the anvil retainer within the through bore of the bushing.

In embodiments, the bushing includes an external slot and the inner housing portion includes an inner wall that defines the through bore. The inner wall of the inner housing portion supports a third longitudinal rib that is received within the external slot of the bushing to prevent rotation of the bushing within the through bore of the inner housing portion.

In some embodiments, the distal portion of the anvil retainer supports a plurality of second longitudinal ribs, wherein each of the plurality of second longitudinal ribs is received within a respective one of the longitudinal channels defined between the resilient legs of the anvil shaft.

In certain embodiments, the bushing is formed from a metal.

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

In some embodiments, the shell assembly is releasably coupled to the body portion.

In certain embodiments, a distal portion of the bushing is formed with spaced rings that are positioned to engage the inner wall of the inner housing portion of the shell housing within the through bore to secure the bushing within the through bore.

In embodiments, the anvil head is pivotally supported on the anvil shaft.

