Method of laser cutting pericardial tissue for use with an implantable medical device

• US RE42,857 E1
• Filed: 04/22/2010
• Issued: 10/18/2011
• Est. Priority Date: 01/27/2000
• Status: Expired due to Term

• Current Assignee: Medtronic ATS Medical, Inc. (Medtronic Plc)
• Original Assignee: 3F Therapeutics Incorporated (Medtronic Plc)
• Inventors: Myers, Keith E., Cali, Douglas S.
• Primary Examiner(s): Pellegrino; Brian E.
• Application Number:
  US12/765,356
• Time in Patent Office: 544 Days
• Field of Search: 600/36, 94/941.1, 623/1.44, 623/2.13, 623/901, 623915-918, 372/25
• US Class Current: 623/2.13
• 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;

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;

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, thereby producing 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. The method of claim 1, comprising moving the laser beam at a cutting speed of about 1 inch per second and a pulse rate of about 1000 pulses per inch.

6. The method of claim 5, wherein the laser beam supplies between about 0.005-0.02 joules of laser energy per pulse.

7. The method of claim 1, wherein the laser beam operates at a wavelength of about 10.6 microns.

8. The method of claim 1, wherein the laser beam operates at a wavelength of about 2.7-3.0 microns.

9. The method of claim 1, wherein the laser energy is about 0.0075 joules per pulse and a laser spot diameter of about 0.003 inches.