The present invention relates to systems and methods for treating spinal cord injuries and other pathologies, and to medical electrode leads and methods for manufacture thereof for use in systems and methods for treating spinal cord injuries and other pathologies. The invention has particular utility in connection with medical implantable leads as replacements or patches for damaged nerves and will be described in connection with such utility, although other utilities are contemplated.
Severe spinal trauma, i.e., in which nerves are severed, and other pathologies such as spina bifida, spinal cord tumors, cauda equina syndrome and the like has left many individuals paralyzed or partially paralyzed, as well as loss of bodily functions (bladder/intestinal/sexual). Paralysis occurs when spinal cord nerves are severed. Generally when the spinal cord is fractured and nerves severed, the patient will lose all use of muscles below the spinal cord fracture.
Researchers have proposed re-growing severed nerves using among others, such as stem cell therapy; however, while such attempts show promise, to date such attempts have not been successful.
The intensity of electrical nerve signals, i.e. signals from the brain to the muscles are extremely low. Thus, the use of conventional small gauge wires to reconnect the severed ends of spinal nerves, or to create new connections between the brain and isolated muscle groups or organs is extremely difficult.
The present invention overcomes the aforesaid and other problems with the prior art, by providing an extremely high surface area fibrous bundle, formed of extremely fine gauge (2 to 50 um diameter fibers) electrically conductive biocompatible metal as replacements or patches for damaged nerves.
The preferred metal comprises tantalum, although other valve metals such as niobium, titanium, zirconium and its alloys which are also biocompatible, advantageously may be used in accordance with the present invention.
The fibrous bundle is formed by combining shaped elements of, e.g. tantalum, or another biocompatible metal, such as niobium, tantalum or titanium, with a ductile material such as copper or silver to form a billet, The billet is then sealed in an extrusion can, and extruded and drawn following the teachings of my prior PCT Application Nos. PCT/US07/79249 or PCT/US08/86460, or my prior U.S. Pat. Nos. 7,480,978 or 7,146,709. The drawn wire is then wrapped or coated in an electrically insulating layer or sheath, leaving one or both ends exposed, and the exposed end or ends are etched, e.g., in HNO3—H2O to completely remove all the copper or silver, surrounding the exposed end or ends, leaving the extremely fine fibers of tantalum extending from the bundle.
Further features and advantages of the present invention will be seen from the following detailed description, taken in conjunction with the accompanying drawings, wherein:
Referring to
The resulting drawn wire is then wrapped in an insulating envelope, 18 in a wrapping step 20, leaving one or both ends exposed, and the copper or silver is then removed from the end or ends, e.g. by etching in, e.g. nitric acid in an etching step 22.
Referring to
The resulting product comprises a bundle 24 of highly flexible, ductile, fine gauge (5 to 50 μm) metallic filaments supported within an insulation wrapped metal core 26 with exposed filaments 30 at one or both ends. A feature and advantage of the present invention is that each filament is bonded to a conductive metal. In essence, each filament is an electrode bonded to a metal post. The exposed filament end or ends of the wire provide an extremely fine high surface area and as such can significantly increase the conductivity of the extremely small electrical signals encountered in the body. Moreover, being formed of a biocompatible material, the exposed filament end or ends advantageously may promote soft tissue growth and in time become one with nerves and muscles. Also, if desired, electrical pulses may be transmitted through the filaments to stimulate nerve growth.
Referring to
While the present invention has particular utility in connection with medical electrode leads as replacements for damaged nerves, the invention also advantageously may be used in connection with other pathologies including, for example, implantable leads for pacemakers and defibrillators, for pain management and other devices implanted into the body, or employed as “electronic tattoos” as a patch adhered to the skin or other tissue as described in the recently published article by Nanshu Lu in Technology Review, September/October, 2012, page 64.
This application claims priority from U.S. Provisional Application Ser. No. 61/898,988, filed Nov. 1, 2013, the contents of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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61898988 | Nov 2013 | US |