Medical devices having textured surfaces

• US 7,955,512 B2
• Filed: 02/13/2007
• Issued: 06/07/2011
• Est. Priority Date: 02/13/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Casey, Kevin, Taylor, Catherine E., Park, Eunsung
• Primary Examiner(s): Alanko; Anita K
• Application Number:
  US11/674,607
• Publication Number:
  US 20070225785A1
• Time in Patent Office: 1,575 Days
• Field of Search: None
• US Class Current: 216/58
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/7002 Longitudinal elements, e.g. rods
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61C 8/0012 characterised by the material or composition, e.g. ceramics, surface layer, metal alloy use of specific materials A61K6/00
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/3099 for temporo-mandibular [TM, TMJ] joints endoprostheses for mandibular reconstruction A61F2/2803
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30925 etched
• CPC Class Codes: A61F 2002/3097 using laser
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2310/00017 Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00071 : Nickel or Ni-based alloys
• CPC Class Codes: A61F 2310/00089 : Zirconium or Zr-based alloys
• CPC Class Codes: A61F 2310/00101 : Molybdenum or Mo-based alloys
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00149 : Platinum or Pt-based alloys
• CPC Class Codes: A61F 2310/00395 : Coating or prosthesis-covering structure made of metals or of alloys
• CPC Class Codes: A61F 2310/0052 : Coating made of silver or Ag-based alloys
• CPC Class Codes: A61F 2310/00574 : Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon
• CPC Class Codes: A61F 2310/0058 : Coating made of diamond or of diamond-like carbon DLC
• CPC Class Codes: A61F 2310/00598 : Coating or prosthesis-covering structure made of compounds based on metal oxides or hydroxides
• CPC Class Codes: A61F 2310/0073 : Coating or prosthesis-covering structure made of compounds based on metal carbides
• CPC Class Codes: A61F 2310/00856 : Coating or prosthesis-covering structure made of compounds based on metal nitrides
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF
• CPC Class Codes: A61L 27/50 : Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 29/14 : Materials characterised by their function or physical properties , e.g. lubricating compositions
• CPC Class Codes: A61L 31/14 : Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61N 1/00 : Electrotherapy; Circuits therefor A61N2/00 takes precedence; irradiation apparatus A61N5/00

Abstract

Disclosed are medical devices having textured surfaces and related methods for texturing. Methods of surface texturing using gas-phase plasma provide medical devices with myriad complex surface morphologies.

Claims

1. A method for providing a medical device with a non-random textured surface comprising;

placing a medical device in a plasma chamber;

reducing the atmospheric pressure within said plasma chamber to provide a process pressure of less than approximately 760 Torr;

providing a non-reactive gas to said plasma chamber while maintaining said process pressure of less than approximately 760 Torr; and

exposing said medical device to said gas phase plasma to achieve surface heating of said device to the point where the surface glows, thereby producing a non-random textured surface on said medical device.

2. A method for providing a medical device with a non-random textured surface comprising;

placing a medical device in a plasma chamber;

reducing the atmospheric pressure within said plasma chamber to provide a process pressure of less than approximately 760 Torr;

providing a non-reactive gas to said plasma chamber while maintaining said process pressure of less than approximately 760 Torr;

applying sufficient power to an radio frequency (RF) source to generate sufficient RF energy in said plasma chamber to generate a gas-phase plasma

providing at least one additional heat source; and

exposing said medical device to said gas phase plasma and said at least one additional heat source to achieve surface heating of said device to the point where the surface glows, thereby producing a non-random textured surface on said medical device.

3. The method according to claim 2 wherein said process pressure ranges from approximately 2 mTorr to approximately 400 mTorr.

4. The method according to claim 2 wherein said RF frequency comprises frequencies from approximately 10 KHz to approximately 80 MHz.

5. The method according claim 2 wherein in said non-reactive gas is selected from the group consisting of nitrogen, helium, neon, argon, krypton, xenon and radon.

6. The method according to claim 5 wherein said non-reactive gas is argon.

7. The method according to claim 2 wherein said RF frequency is generated from an RF-biased stage and wherein said RF frequency is continuous, pulsed or any combination thereof.

8. The method according to claim 2 wherein said applying step further comprises isolating said medical device from said RF frequency source.

9. The method according to claim 2 wherein said applying step further comprises placing said medical device in direct contact with said RF frequency source.

10. The method according to claim 2 wherein said power comprises wattages of between approximately 5 W and approximately 5000W.

11. The method according to claim 10 wherein said power comprises wattages of between approximately 100 W and approximately 1000 W.

12. The method according to claim 2 wherein said RF frequency is between approximately 40 KHz to approximately 28 MHz.

13. The method according to claim 12 wherein said RF frequency is between approximately 2 MHz and approximately 14 MHz.

14. The method according to claim 2 wherein said process pressure is achieved with non-reactive gas flows of about 2 sccm and about 150 sccm.

15. The method according to claim 2 wherein said medical device is selected from the group consisting of neurostimulators, catheters, cardiac valves, shunts, pacemakers, implantable cardioverter defibrillators, vascular stents, stent grafts, drug-delivery devices, bone screws, bone covers, spinal plates, tracheal stents, medical prosthesis, feeding tubes, trocar needles, clamps, and forceps.

16. The method of claim 15 wherein said medical device comprises materials selected from the group consisting of stainless steel, MP35N alloy, Pt—

Ir, commercially pure titanium (CP Ti), tantalum, nickel titanium alloys, Ti-6Al-4V, cobalt chrome alloys, zirconium, zirconium alloys, molybdenum alloys and combinations thereof.

17. The method according to claim 2 wherein said at least one additional heat source is provided by RF-field effect, kinetic energy, electromagnetic radiation, induction energy, resistive heat energy or laser energy.

18. A method for providing a medical device with a non-random textured surface comprising;

placing a medical device in a plasma chamber;

reducing the atmospheric pressure within said plasma chamber to provide a process pressure of between approximately 100 Torr and approximately 10<sup>−

9</sup> Torr;

providing a stream of argon gas at between approximately 2 sccm and about 150 sccm to said plasma chamber while maintaining said process pressure of between approximately 100 Torr and approximately 10<sup>−

9</sup> Torr;

applying between approximately 100 W and approximately 1000 W of power to an radio frequency (RF) source to generate an RF frequency of between approximately 2 MHz and approximately 14 MHz;

providing at least one additional heat source;

exposing said medical device to said heat source to achieve surface heating; and

maintaining said surface heating for a time of between approximately 1 minute and 20 minutes to achieve a surface glow, thereby producing a non-random textured surface on said medical device.

19. The method according to claim 18 wherein said process pressure is between 10⁻

2 and <sup>−

5</sup> Torr.

20. The method according to claim 18 wherein said RF frequency is 13.56 MHz.

21. The method according to claim 18 wherein said at least one additional heat source is provided by RF-field effect, kinetic energy, electromagnetic radiation, induction energy, resistive heat energy or laser energy.

22. A method for providing a non-random texture on a medical device with a combined system of inductively coupled plasma and induction heating comprising:

placing a medical device in a plasma chamber;

wrapping an induction coil around said medical device;

applying power though said induction coil resulting in the heating of said medical device;

reducing the atmospheric pressure within said plasma chamber to provide a process pressure of less than approximately 760 Torr;

providing a non-reactive gas to said plasma chamber while maintaining said process pressure of less than approximately 760 Torr; and

exposing said medical device to said gas phase plasma to achieve surface heating of said device to the point wherein the surface glows, thereby producing a non-random textured surface on said medical device.

23. The method according to claim 22 wherein said medical device is selected from the group consisting of implantable medical devices, leads, vascular stents, dental wires, dental screws, artificial temporomandibular joints, bone screws, plates, hip prosthesis, bone nails, wires, pins, artificial knee implants, tubular pins, spinal implants, ophthalmic drug delivery devices, ophthalmic rods, surgical tools, dental implants, orthopedic implants and micro-abrasion devices.

24. The method according to claim 22 wherein said medical device is comprised of a material selected from the group consisting of metals, metal alloys, polymers and ceramics.

25. The method according to claim 22 wherein said power is applied to said induction coil in alternating current, resulting in a magnetic field.

26. The method according to claim 25 wherein said power is applied to said induction coil at an alternating current frequency of between approximately 1 kHz and approximately 60 MHz.

27. The method according to claim 26 wherein said frequency is between approximately 5 kHz and approximately 30 kHz and said surface texturing penetrates said medical device deeply.

28. The method according to claim 26 wherein said frequency is between approximately 100 kHz and approximately 500 kHz and said surface texturing penetrates said medical device shallowly.

29. The method according to claim 26 wherein said frequency is between approximately 400 kHz and approximately 60 MHz.

30. The method according to claim 22 wherein said induction heating and said plasma generation systems each have their own RF power supply.

31. The method according to claim 30 wherein each RF power supply generates a different RF frequency.