Method of cutting material for use in implantable medical device

• US 20050098547A1
• Filed: 12/08/2004
• Published: 05/12/2005
• Est. Priority Date: 07/26/2001
• Status: Active Grant

• Current Assignee: 3F Therapeutics Incorporated (Medtronic Plc)
• Original Assignee: 3F Therapeutics Incorporated (Medtronic Plc)
• Inventors: Myers, Keith E., Cali, Douglas S.
• Granted Patent: US 7,594,974 B2
• Time in Patent Office: Days
• US Class Current: 219/121.72
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/30 Organic material
• CPC Class Codes: B23K 2103/38 Fabrics, fibrous materials
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/32 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/324 involving non-metallic parts
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: Y10T 156/1054 and simultaneously bonding [e.g., cut-seaming]

Abstract

A method of cutting material for use in an implantable medical device employs a plotted laser cutting system. The laser cutting system is computer controlled and includes a laser combined with a motion system. The laser precisely cuts segments out of source material according to a predetermined pattern as designated by the computer. The segments are used in constructing implantable medical devices. The cutting energy of the laser is selected so that the cut edges of the segments are melted to discourage delamination or fraying, but communication of thermal energy into the segment beyond the edge is minimized to avoid damaging the segment adjacent the edge.

Claims

1. A method of creating an implantable medical prosthesis, comprising:

providing a sheet of pericardium, wherein the pericardium has at least two tissue layers; and

cutting a segment of tissue out of the sheet of pericardium with a laser beam;

said cutting comprising operating a laser at a power and pulse rate such that said beam welds the layers of the pericardium together along a laser cut edge without significantly burning the pericardium adjacent the cut edge.

2. The method of claim 1, wherein the pericardium tissue comprises equine pericardium.

3. The method of claim 1, wherein the laser beam power and pulse rate are selected so that there is substantially no discoloration of the pericardium along the cut edge.

4. The method of claim 1, wherein the prosthesis comprises a heart valve, said cutting comprising cutting a plurality of segments of tissue out of the sheet of pericardium with the laser beam and attaching the cut segments to one another to form the valve.

5. An apparatus for cutting a prosthetic segment, the apparatus comprising:

a source material segment;

a support platform supporting the source material segment;

a beam assembly positioned to direct a beam at the source material segment; and

a motion system that controls the relative position of the support platform and the beam.

6. The apparatus of claim 5 further comprising an electronic mechanism that changes the relative position of the support platform and the beam.

7. The apparatus of claim 6 wherein the motion system actuates the electronic mechanism to adjust the relative position of the laser beam.

8. The apparatus of claim 6 wherein the electronic mechanism is connected to the laser beam to move the laser beam relative to the support platform.

9. The apparatus of claim 5 wherein the motion system comprises a digital processor connected to the electronic mechanism, wherein the motion system controls the electronic mechanism with a printer driver.

10. The apparatus of claim 5 wherein the digital processor further comprises cutting patterns.

11. The apparatus of claim 9 wherein the digital processor further comprises a computer assisted design software program.

12. The apparatus of claim 11 wherein the computer assisted design software program further comprises a template.

13. The apparatus of claim 5 wherein the laser tube assembly further comprises optical elements within the laser tube assembly to direct a focused laser beam on the support platform, and wherein the motion system is operably connected to the optical components to move the optical components relative to the support platform.

14. The apparatus of claim 13 wherein the optical components further comprises lenses.

15. The apparatus of claim 14 wherein the optical components further comprises mirrors.

16. The apparatus of claim 5 wherein the source material segment further being of equine pericardium.

17. The apparatus of claim 5 wherein the beam assembly further comprises a laser.

18. The apparatus of claim 17 wherein the laser is operated in a pulsed manner, supplying between about 0.005-0.5 joules of laser energy per pulse, with a laser spot size of about 0.002-0.005 inches in diameter.

19. The apparatus of claim 17 wherein the laser is operated at a cutting speed of about 1 inch per second and a pulse rate of about 1000 pulses per inch.

20. The apparatus of claim 17, wherein the laser beam operates at a wavelength of about 10.6 microns.

21. The apparatus of claim 17, wherein the laser beam operates at a wavelength of about 2.7-3.0 microns.

22. The apparatus of claim 17, wherein the laser energy is about 0.0075 joules per pulse and a laser spot diameter of about 0.003 inches.

23. The apparatus of claim 18 wherein the range of laser energy per probe is between about 0.005 and 0.02 joules.

24. A method of creating an implantable medical prosthesis, comprising:

providing a sheet of pericardium, wherein the pericardium has at least two tissue layers; and

cutting a segment of tissue out of the sheet of pericardium with a laser beam;

said cutting comprising operating a laser at a power and pulse rate having the following parameters;

1.5 lens, 20 percent power setting, 3.4 percent speed, 1,000 pulses per inch and 1,000 dots per inch, such that said beam welds the layers of the pericardium together along a laser cut edge without significantly burning the pericardium adjacent the cut edge.