Material combinations and processing methods for a surgical instrument

Patent metadata

Field	Value
Publication number	US-12048431-B2
Application number	US-202117514180-A
Country	US
Kind code	B2
Filing date	Oct 29, 2021
Priority date	Oct 29, 2020
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

Surface preparation for sliding surfaces can enhance wear performance for surgical instruments such as surgical staplers which include reusable mechanisms that are used multiple times with single use reload cartridges. To reduce the potential for galling wear in a metal-to-metal sliding engagement, a combination of surface hardening, surface finish, and surface coatings can be applied to metallic components of a surgical instrument. Surface hardening techniques can allow further manufacturing operations such as welding without compromising the strength of the underlying metal substrate. With stainless steel metal substrates, as surface or case hardening techniques can reduce corrosion resistance, a surface coating can be applied to inhibit surface oxidation as well as provide a barrier to metal-to-metal contact. A further lubricious coating layer such as a bone wax coating layer can enhance galling resistance.

First claim

What is claimed is:

1. A surgical instrument comprising:
an end effector comprising:
a first jaw, and
a second jaw pivotably coupled to the first jaw;

a firing member longitudinally slidable with respect to the end effector to pivotably move the second jaw with respect to the first jaw and actuate the end effector, wherein the firing member comprises a first sliding surface and the end effector comprises a second sliding surface, the first sliding surface in sliding engagement with the second sliding surface;
wherein at least one of the first sliding surface and the second sliding surface comprises: a metallic substrate, a dry film surface coating disposed on the metallic substrate, and a bone wax layer disposed on the dry film surface coating; and
wherein the metallic substrate comprises a core and a case hardened layer, the case hardened layer positioned adjacent the sliding engagement between the first sliding surface and the second sliding surface, and wherein the dry film surface coating and the bone wax layer are disposed on the case hardened layer to prevent sliding engagement of the metallic substrate during sliding engagement of the first sliding surface with the second sliding surface.

2. The surgical instrument of claim 1 , wherein the case hardened layer is hardened to a hardness within the range of approximately 45 HRC to approximately 70 HRC.

3. The surgical instrument of claim 1 , wherein the case hardened layer is formed by a diffusion process.

4. The surgical instrument of claim 1 , wherein the metallic substrate comprises a grade 17-4 stainless steel material.

5. The surgical instrument of claim 4 , wherein the metallic substrate is heat treated to an H900 condition.

6. The surgical instrument of claim 1 , wherein the metallic substrate comprises a grade 420 stainless steel material.

7. The surgical instrument of claim 1 , wherein the first jaw, the second jaw, and the firing member each comprise a metallic substrate comprising a core and a case hardened layer hardened to at least 55 HRC.

8. The surgical instrument of claim 1 , wherein the metallic substrate has a surface finish roughness of between approximately 25 μin and 75 μin.

9. The surgical instrument of claim 8 , wherein the metallic substrate comprises a tumbled surface finish.

10. The surgical instrument of claim 1 , wherein the dry film surface coating comprises an oxidation inhibiting coating.

11. The surgical instrument of claim 10 , wherein the dry film surface coating comprises a polytetrafluoroethylene surface coating.

12. The surgical instrument of claim 1 , wherein the core has a first hardness, and wherein the case hardened layer has a second hardness greater than the first hardness.

13. The surgical instrument of claim 12 , wherein the case hardened layer defines a surface layer having a predetermined depth.

14. A surgical stapler comprising:
an elongate shaft extending from a proximal end to a distal end;
a jaw assembly at the distal end of the elongate shaft, the jaw assembly comprising:
a cartridge support configured to receive a reload cartridge having a plurality of staples disposed therein;
an anvil, wherein the cartridge support and the anvil are pivotably movable between an open and a closed configuration; and
a firing member longitudinally slidable in engagement with the cartridge support and the anvil in the closed configuration to fire staples, the firing member comprising a first sliding surface and the jaw assembly comprising a second sliding surface, the first sliding surface in sliding engagement with the second sliding surface;

wherein at least one of the first sliding surface and the second sliding surface comprises: a case hardened metallic substrate comprising a case hardened surface layer, a dry film surface coating disposed on the case hardened metallic substrate, and a bone wax layer disposed on the dry film surface coating, the case hardened surface layer positioned adjacent the sliding engagement between the first sliding surface and the second sliding surface, and wherein the dry film surface coating and the bone wax layer are disposed on the case hardened surface layer to prevent sliding engagement of the case hardened metallic substrate during sliding engagement of the first sliding surface with the second sliding surface.

15. The surgical stapler of claim 14 , wherein the case hardened metallic substrate is case hardened to at least approximately 55 HRC.

16. The surgical stapler of claim 14 , wherein the case hardened metallic substrate is case hardened with a diffusion process.

17. The surgical stapler of claim 14 , wherein each of the anvil, the cartridge support, and the firing member comprise a case hardened metallic substrate, a dry film surface coating disposed on the case hardened metallic substrate, and a bone wax layer disposed on the dry film surface coating.

Assignees

• Applied Med Resources

Inventors

• Krasts Andrew
• Darnall Darci
• Weiss Eric J
• Hopkins Timothy M

Classifications

• A61B2017/00933

  bone or bone-like · CPC title

• A61B2017/00845

  of moving parts with respect to each other · CPC title

• A61B2017/00836

  corrosion-resistant (A61B2017/00853 takes precedence; preventing galvanic or electrolytic corrosion in prostheses A61F2210/0009) · CPC title

• A61B2017/00526

  Methods of manufacturing · CPC title

• A61B2017/07214

  Stapler heads · CPC title