# US 2014/0197225 A1 · Circular Stapling Instrument > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197225 A1 - Document ID: US20140197225A1 - Status: Published application - Kind: A1 - Application number: 13/739,246 - Filed: 2013-01-11 - Published: 2014-07-17 - Earliest claimed: 2013-01-11 - Assignees: Covidien LP - Applicants: Covidien LP - Inventors: Christopher Penna - Web page: https://patentgrep.com/patent/US20140197225A1 ## CPC - A61B 17/1155: {Circular staplers comprising a plurality of staples} - A61B 17/068: Surgical staplers {, e.g. containing multiple staples or clamps}({staplers containing only one staple A61B17/10; magazines or containers for staples A61B17/105;} for performing anastomosis A61B17/115; {staplers in general B25C5/00}) - A61B 17/32: Surgical cutting instruments ({A61B18/042 takes precedence; suture cutters A61B17/0467;} implements for ligaturing and cutting {A61B17/122, A61B17/12; instruments for rupturing the amniotic membrane A61B17/4208; specially adapted knives for eye surgery A61F9/0133}) - A61B 17/072: for applying a row of staples in a single action, e.g. the staples being applied simultaneously - A61B 17/07207: {the staples being applied sequentially} - A61B 2017/07214: {Stapler heads} - A61B 2017/07285: {characterised by its cutter} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A circular stapling instrument including a stapling forming assembly that is actuated independently from actuation of the cutting assembly is provided. The instrument includes a handle assembly, an elongate body extending from the handle assembly, a cartridge assembly mounted on a distal end of the elongate body. The cartridge assembly includes a pusher assembly and a knife assembly. The knife assembly is selectively fixed relative to the pusher assembly. ## Claims ### Claim 1 A circular stapler comprising: a handle assembly; an elongate body extending from the handle assembly; and, a cartridge assembly mounted on a distal end of the elongate body, the cartridge assembly including a pusher assembly and a knife assembly, wherein the knife assembly is selectively fixed relative to the pusher assembly for independent movement relative to the pusher assembly, the knife assembly being initially detached from the pusher assembly in a first stroke, and subsequently attached to the pusher assembly in a second stroke. ### Claim 2 (depends on 1) The circular stapler of claim 1, wherein the pusher assembly includes a pusher adapter configured to be advanced a first distance and retracted a second distance, the second distance being greater than the first distance. ### Claim 3 (depends on 2) The circular stapler of claim 2, wherein the knife assembly supports a snap ring therearound and the pusher adapter includes a ridge formed about an inner surface thereof configured to engage the snap ring of the knife assembly. ### Claim 4 (depends on 1) The circular stapler of claim 1, wherein the knife assembly includes a knife carrier, a knife supported on and extending distally from the knife carrier and a snap ring supported around a proximal portion of knife carrier. ### Claim 5 (depends on 4) The circular stapler of claim 4, wherein the knife carrier includes an annular groove configured to accommodate the snap ring when the snap ring is in a radially compressed condition and when the snap ring is in an uncompressed condition. ### Claim 6 (depends on 6) The circular stapler of claim 6, wherein the snap ring does not extend beyond an outer diameter of the knife carrier when the snap ring is in the compressed condition. ### Claim 7 (depends on 5) The circular stapler of claim 5, wherein the snap ring extends beyond an outer diameter of the knife carrier when the snap ring is in the uncompressed condition. ### Claim 8 (depends on 5) The circular stapler of claim 5, wherein the knife carrier further includes a step formed in the annular groove configured to engage the snap ring when the snap ring is in the uncompressed condition. ### Claim 9 (depends on 8) The circular stapler of claim 8, wherein the step is configured to prevent radial compression of the snap ring during a tissue cutting stroke. ### Claim 10 (depends on 1) The circular stapler of claim 1, wherein the cartridge assembly includes a housing having an outer cylindrical portion and an inner cylindrical portion, wherein the pusher assembly and knife assembly are substantially cylindrical and are selectively received between the inner and outer cylindrical portions of the housing. ### Claim 11 A method of stapling tissue, comprising the steps of: providing a surgical stapling instrument having a pusher and a knife assembly, wherein the knife assembly is selectively connected relative to the pusher assembly for independent movement relative to the pusher assembly; advancing the pusher assembly to cause an ejection and a forming of staples; retracting a pusher adapter of the pusher assembly; and advancing the pusher adapter to cause an advancement of the knife assembly and a cutting of tissue. ### Claim 12 (depends on 11) The method of claim 11, further including the step of providing a lapse of time between the ejection and forming of the staples and the cutting of tissue to allow for tissue normalization. ### Claim 13 (depends on 11) The method of claim 11, wherein the step of retracting the pusher adapter includes retracting the pusher adapter to a location proximal of an initial location of the pusher adapter.