WO2017197594A1

WO2017197594A1 - Method of manufacturing an anvil assembly

Info

Publication number: WO2017197594A1
Application number: PCT/CN2016/082458
Authority: WO
Inventors: Shaohui Shi
Original assignee: Covidien Lp; Covidien (China) Medical Devices Technology Co., Ltd.
Priority date: 2016-05-18
Filing date: 2016-05-18
Publication date: 2017-11-23

Abstract

A method of manufacturing an anvil assembly (10) is provided that includes injection molding an anvil base (16), the anvil base (16) defining a stepped central bore (28) having a shoulder and a tissue contact surface (22) having a plurality of annular rows of staple deforming pockets (24); forming an anvil stem (18) having a flange (42) configured and dimensioned to be received in the stepped bore (28) of the anvil base (16); inserting the anvil stem (18) through the stepped central bore (28) of the anvil base (16) and positioning the flange (42) on the shoulder of the stepped central bore (28); and securing the anvil base (16) to the anvil stem (18).

Description

METHOD OF MANUFACTURING AN ANVIL ASSEMBLY

BACKGROUND

1. Technical Description

The present disclosure relates to a method of manufacturing an anvil assembly and, more particularly, to a method of manufacturing an anvil head of an anvil assembly for a surgical stapling device having three annular rows of staple forming pockets.

2. Background of Related Art

Surgical stapling devices are commonly used to expedite tissue suturing processes during surgical procedures and are available in a variety of configurations. Each configuration is best suited to perform particular surgical procedures. For example, circular stapling devices are configured to perform end to end anastomosis procedures wherein ends of tubular sections of a body lumen are joined together to provide a single intact body lumen.

The desire to improve the effectiveness of stapling processes is ongoing. One stapling device to improve the effectiveness of the stapling process includes a cartridge assembly having a cartridge body with three rows of staples positioned to be driven into three corresponding rows of staple pockets formed on an anvil assembly. In the device, the staples in each row are sized to vary the compression applied to the sutured tissue to control blood flow adjacent the anastomosis site to prevent unwanted necrosis of tissue.

Surgical stapling devices are commonly used in procedures in which the stapling device is inserted into a patient through a body orifice. In these procedures, the outer diameter of the stapling device is minimized to minimize trauma to the patient. In circular stapling devices configured for insertion through a body orifice, it has proved to be challenging to form three rows of staple deforming pockets on a small diameter anvil head of an anvil assembly in a cost effective manner. Thus, a continuing need exists for an improved manufacturing process for manufacturing an anvil assembly of a surgical stapling device including an anvil head having three rows of staple deforming pockets in a cost effective manner.

SUMMARY

One aspect of the present disclosure is directed to a method of manufacturing an anvil assembly including injection molding an anvil base, the anvil base defining a stepped central bore having a shoulder and a tissue contact surface having a plurality of annular rows of staple deforming pockets； forming an anvil stem having a flange configured and dimensioned to be received in the stepped bore of the anvil base； inserting the anvil stem through the stepped central bore of the anvil base and positioning the flange on the shoulder of the stepped central bore； and securing the anvil base to the anvil stem.

In embodiments, injection molding an anvil base includes injection molding the anvil base from a material having high strength and rigidity.

In some embodiments, the material is a polyacrylamide compound.

In certain embodiments, the material is an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide.

In embodiments, forming an anvil stem includes forming the anvil stem from a stainless steel.

In some embodiments, the stainless steel is a 17-4 PH stainless steel.

In certain embodiments, forming an anvil stem includes forming the anvil stem using computer numerical control.

In embodiments, securing the anvil base to the anvil stem includes welding the anvil base to the anvil stem.

In some embodiments, the method further includes securing an anvil center rod to the anvil base.

Another aspect of the present disclosure is directed to a method of manufacturing an anvil assembly that includes injection molding an anvil base from a polyacrylamide compound, the anvil base defining a stepped central bore having a shoulder and a tissue contact surface having a plurality of annular rows of staple deforming pockets； forming an anvil stem from a stainless steel, the anvil stem having a flange configured and dimensioned to be received in the stepped bore of the anvil base； inserting the anvil stem through the stepped central bore of the anvil base and positioning the flange on the shoulder of the stepped central bore； and securing the anvil base to the anvil stem.

In embodiments, the polyacrylamide compound is an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide.

In some embodiments, the stainless steel is a 17-4 PH stainless steel.

In certain embodiments, securing an anvil center rod to the anvil base includes pivotally securing the anvil center rod to the anvil base using a pivot pin.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed method of manufacturing an anvil assembly including an anvil head having three annular rows of staple are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a surgical stapling device including an anvil assembly manufactured using the presently disclosed method including three annular rows of staples；

FIG. 1A is an enlarged view of the indicated area of detail shown in FIG. 1；

FIG. 2 is a side perspective view of the anvil head of the anvil assembly shown in FIG. 1 with the parts separated；

FIG. 3 is a side perspective view of the anvil head of the anvil assembly shown in FIG. 1 assembled； and

FIG. 4 is a cross-sectional view taken along section lines 4-4 of FIG. 3.

DETAILED DESCRIPTION OF EMBODIMENTS

The presently disclosed method of manufacturing an anvil assembly including an anvil head having three annular rows of staple deforming pockets 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. In this description, the term “proximal” is used generally to refer to the portion of the apparatus that is closer to a clinician, while the term “distal” is used generally to refer to the portion of the apparatus 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.

The presently disclosed method for manufacturing an anvil assembly for a circular stapling device including an anvil head having three annular rows of staple deforming pockets includes manufacturing the anvil head from two separate components including an anvil base and an anvil stem. The anvil base includes a smooth, distal surface, and a proximal surface defining the three rows of staple deforming pockets. In embodiments, the anvil base is injection molded from a material having high strength and rigidity such as a polyacrylamide compound. In embodiments, the base is formed from an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide. In some embodiments, the anvil stem is formed from a stainless steel such as a 17-4 PH stainless steel that is a martensitic precipitation-hardened stainless steel that has strength, good corrosion resistance, and good toughness in both base metal and welds. By forming the base from a material such as a polyacrylamide, as compared with stainless steel, the cost of manufacture of the anvil head can be reduced.

FIGS. 1 and 1A illustrate a surgical stapling device 100 including one embodiment of an anvil assembly 10 formed by the presently disclosed manufacturing method. The stapling device 100 includes a handle assembly or actuator 102, an elongated body 104 extending distally from the handle assembly 102, and a shell or cartridge assembly 106. An anvil retainer 108 extends distally from the elongated body 104 and through the shell assembly 106. The handle assembly 102 includes a firing trigger 110 and a rotatable approximation knob 112. Although shown as being a manually actuable handle assembly 102, the handle assembly may be a powered handle assembly. U.S. Patent No. 7,303,106 ( “the ‘106 Patent” ) and U.S. Patent Publication No. 2014/0263556 ( “the ‘556 Publication” ) disclose examples of surgical stapling devices including manually actuated and powered handle assemblies, respectively, which are incorporated herein by reference in their entirety.

The shell assembly 106 includes, inter alia, an annular cartridge 114 that supports three annular rows of staple pockets (not shown) . Each of the staple pockets receives a staple. A distal end of the anvil retainer 108 releasably supports the anvil assembly 10 for movement between a position spaced from the annular cartridge 114 and a position in close approximation with the annular cartridge 114. More specifically, the anvil retainer 108 is axially movable between advanced and retracted positions in response to actuation of the rotation knob 112 to move the anvil assembly 10 in relation to the annular cartridge 114 between the spaced and approximated positions. Such an approximation mechanism that interconnects the rotation knob 112 to the anvil retainer 108 is described in detail in the ‘106 Patent above.

Referring to FIGS. 1A and 2, the anvil assembly 10 includes an anvil head 12 and an anvil center rod 14. The anvil head 12 includes an anvil base 16 and an anvil stem 18. The anvil base 16 has a circular body 16a having a smooth, atraumatic distal face 20 that allows the anvil head 16 to pass atraumatically through a vessel lumen (not shown) . A proximal side of anvil head 12 includes a tissue contact surface 22 including three annular rows of staple deforming pockets 24 and an annular recess 26. The body 16a defines a stepped, central bore 28 that is configured to receive the anvil stem 18 as described in further detail below. In certain embodiments, the body 16a also defines a plurality of vent openings 41 (FIG. 2) that allow fluid from tissue being compressed between the anvil head 12 and the annular cartridge 114 to escape from the device 100. The annular recess 26 is dimensioned and configured to receive a cut ring assembly 27 (FIG. 1A) that is positioned about the central bore 28 at a position to engage an annular knife (not shown) of the shell assembly 106. The ‘106 Patent discloses an anvil head including a cut ring assembly.

The anvil stem 18 includes a body 30 that defines a transverse bore 32 that receives a pivot pin 34 (FIG. 1A) to pivotally secure the anvil head 12 to the center rod 14. More specifically, the distal end of the center rod 14 includes a clevis 36 (FIG. 1A) that defines transverse bores 40 that are aligned with the transverse bore 32 of the anvil stem 18. The pivot pin 34 is received within the

bores

32 and 40 of the body 30 and clevis 36, respectively, to pivotally secure the anvil head 12 to the center rod 14. This structure is also described in detail in ‘106 Patent. Further details of the anvil assembly 10 not directly relevant to this disclosure are also described in detail in the ‘106 Patent.

Referring to FIGS. 3 and 4, the body 30 of the anvil stem 18 also includes a flange 42 having a distal face 46. The flange 42 is received in the stepped, central bore 28 of the body 16 of the anvil head 16 such that the distal face 46 of the flange 42 is substantially flush with the outer distal face 20 of the body 16.

In embodiments, the anvil head 12 of the anvil assembly 10 is manufactured by forming the anvil base 16 and the anvil stem 18 separately and securing the components together. In some embodiments, the anvil base 16 is injection molded from a material having high strength and rigidity such as a polyacrylamide compound. In certain embodiments, the base 16 is formed from an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide. This material has outstanding surface gloss, excellent creep resistance, and a tensile strength of more than 250 Mpa. Alternately, it is envisioned that other materials having similar characteristics may also be used to construct the anvil base 16.

In some embodiments, the anvil stem 18 is formed from a material having a high strength, good corrosion resistance, and good toughness such as a stainless steel. In embodiments, the anvil stem 18 is formed from a 17-4 PH stainless steel that is a martensitic precipitation-hardened stainless steel that has high strength, good corrosion resistance, and good toughness in both base metal and welds.

In embodiments, the anvil stem 18 is formed or machined using computer numerical control (CNC) . In CNC systems, machine tools are operated by precisely controlled programmed commands encoded on a storage medium. The movements of the machine tools are automated using computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. Known CNC systems incorporate multiple tools into a single CNC installation to facilitate formation of a single component that may require multiple machining operations. For example, the CNC system may include a lathe or grinding tool, and a drill to facilitate formation of the body 30 and the bore 32 of the anvil stem 18.

In embodiments, the anvil base 16 includes a special coating to increase the surface hardness of the tissue contact surface 22. The special coating may include nanovate plating. By providing the tissue contact surface 22 of the anvil base 16 with a nanovate plating, the surface hardness of the tissue contact surface 22 including the three annular rows of staple deforming pockets 24 can be increased to greater than HV320 greater than that of 17-4PH stainless steel.

In embodiments, the anvil stem 18 is inserted through the stepped, central bore 28 of the anvil base 16 in the direction indicated by arrow “A” in FIG. 2 such that the flange 42 rests within the stepped bore 28 and the distal face 46 of the anvil base 16 is substantially flush with the distal face 20 of the anvil base 16. The anvil base 16 may be welded to the anvil stem 18. Alternately, other fastening techniques or methods can be used to secure the anvil stem 18 to the anvil base 16.

After the anvil base 16 and the anvil stem 18 are secured together, the anvil head 12 is secured to the center rod 14. More specifically, the pivot pin 34 is inserted through the

bores

32 and 40 of the anvil base 18 and the center rod 14, respectively, to pivotally secure the anvil head 12 to the center rod 14.

In known anvil heads, the area most susceptible to fracture is the anvil stem 18. In contrast, the anvil base 16 is less susceptible to fracture. In the presently disclosed anvil head 12, the anvil stem 16 is formed from a high strength material, e.g., stainless steel, to minimize the likelihood of fracture. In contrast, the anvil base 16, which is less susceptible to fracture, is formed separately from a less expensive material to reduce the overall cost of the anvil head 12. By providing a special coating, e.g., nanovate plating, on the tissue contacting surface 22 of the anvil base 16, the hardness of the less expensive material used to form the anvil base 16 is increased to improve the characteristics of the tissue contacting surface 22 to that of the more expensive material, e.g., stainless steel. In addition, by forming the anvil base 16 from an injection moldable material, the complexity of the method of manufacturing the three annular rows of staple deforming pockets 24 is reduced to simplify and lessen the cost of the manufacturing process.

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 present 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

A method of manufacturing an anvil assembly including:

injection molding an anvil base, the anvil base defining a stepped central bore having a shoulder and a tissue contact surface having a plurality of annular rows of staple deforming pockets；

forming an anvil stem having a flange configured and dimensioned to be received in the stepped bore of the anvil base；

inserting the anvil stem through the stepped central bore of the anvil base and positioning the flange on the shoulder of the stepped central bore； and

securing the anvil base to the anvil stem.
The method of claim 1, wherein injection molding an anvil base includes injection molding the anvil base from a material having high strength and rigidity.
The method of claim 2, wherein the material is a polyacrylamide compound.
The method of claim 3, wherein the material is an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide.
The method of claim 2, wherein forming an anvil stem includes forming the anvil stem from a stainless steel.
The method of claim 5, wherein the stainless steel is a 17-4 PH stainless steel.
The method of claim 5, wherein forming an anvil stem includes forming the anvil stem using computer numerical control.
The method of claim 3, wherein forming an anvil stem includes forming the anvil stem from a stainless steel.
The method of claim 8, wherein securing the anvil base to the anvil stem includes welding the anvil base to the anvil stem.
The method of claim 1, further including securing an anvil center rod to the anvil base.
The method of claim 10, wherein securing an anvil center rod to the anvil base includes pivotally securing the anvil center rod to the anvil base using a pivot pin.
The method of claim 3, wherein forming an anvil stem includes forming the anvil stem from a stainless steel.
A method of manufacturing an anvil assembly including:

injection molding an anvil base from a polyacrylamide compound, the anvil base defining a stepped central bore having a shoulder and a tissue contact surface having a plurality of annular rows of staple deforming pockets；

forming an anvil stem from a stainless steel, the anvil stem having a flange configured and dimensioned to be received in the stepped bore of the anvil base；

inserting the anvil stem through the stepped central bore of the anvil base and positioning the flange on the shoulder of the stepped central bore； and

securing the anvil base to the anvil stem.
The method of claim 13, wherein the polyacrylamide compound is an IXEF 1032 glass-fiber reinforced general purpose polyacrylamide.
The method of claim 14, wherein the stainless steel is a 17-4 PH stainless steel.
The method of claim 13, wherein forming an anvil stem includes forming the anvil stem using computer numerical control.
The method of claim 13, wherein securing the anvil base to the anvil stem includes welding the anvil base to the anvil stem.
The method of claim 13, further including securing an anvil center rod to the anvil base.
The method of claim 18, wherein securing an anvil center rod to the anvil base includes pivotally securing the anvil center rod to the anvil base using a pivot pin.