Prostheses and methods for promoting nerve regeneration and for inhibiting the formation of neuromas

• US 4,778,467 A
• Filed: 07/10/1986
• Issued: 10/18/1988
• Est. Priority Date: 04/25/1984
• Status: Expired due to Fees

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah (State of Utah)
• Inventors: Triolo, Philip M., Todd, R. Joseph, Stensaas, Larry J.
• Primary Examiner(s): Apley, Richard J.
• Assistant Examiner(s): Cannon, Alan W.
• Application Number:
  US06/884,088
• Time in Patent Office: 831 Days
• Field of Search: 623/12, 623/66, 623/1, 623/8, 128/334 R, 128/335.5, 128/334 C, 128/335, 427/2
• US Class Current: 623/23.64
• CPC Class Codes: A61B 17/1128 of nerves
• CPC Class Codes: A61F 2/04 Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts A61F2/18, A61F2/20 take precedence; devices, other than stent-grafts, providing patency to, or preventing collapsing of, tubular structures of the body other than stent-grafts, e.g. stents A61F2/82; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2230/0069 cylindrical

Abstract

The present invention is directed to prosthesis and methods for promoting nerve regeneration. The proximal and distal ends of a severed nerve are brought into close proximity and are enclosed by a tubular prosthesis. In one preferred embodiment, a epineurial or endoneurial monosuture is used to hold the nerve ends in close proximity. A tight seal is formed between the prosthesis and the injured nerve so as to isolate the injured nerve within the prosthesis from the rest of the body of the host. Additionally, in one preferred embodiment, nerve grafts may be incorporated into the prosthesis and nerve regeneration promoting substances may be incorporated within the nerve graft to further enhance nerve regeneration. In another preferred embodiment, a prosthesis is coated with a material which is slippery with relation to the surrounding body tissue and the prosthesis is formed of or coated with a material around the inside of the prosthesis which will substantially adhere to the severed nerve ends so as to prevent substantial movement of the severed nerve ends within the prosthesis. In yet another preferred embodiment, such an outside coating around the prosthesis terminates in two longitudinal flaps which serve to form a fluid-tight seal along the tubular prosthesis. In still another preferred embodiment, the ends of the prosthesis overlap and are formed so as to bias against each other in a spiral tube configuration, thereby providing for firm closure of the prosthesis around a variety of sizes of injured nerves. Also disclosed are various devices and methods for inhibiting the formation of neuromas, such as an open-ended tube or a neuroma-inhibition device formed as a cap member having a reservoir formed therein.

Claims

1. A nerve prosthesis, comprising:

a tube constructed of biocompatible materials having a first end for enclosing a proximal end of a severed nerve and a second end for enclosing a distal end of the severed nerve, said tube serving to support the severed nerve such that the proximal end of the nerve is positioned in proximity to the distal end of the nerve, said tube being substantially impermeable to fluids associated with the severed nerve;

a coating applied to at least a portion of the interior surface of the tube, said coating comprising a material which substantially adheres to the severed nerve ends within the tube so as to substantially inhibit movement of the severed nerve ends within the tube;

a longitudinal slit formed along the length of the tube, said slit allowing the tube to be longitudinally opened so as to facilitate insertion of the severed nerve ends into the tube;

two longitudinal flaps positioned along the respective edges of the longitudinal slit, said flaps providing for a close seal along the slit when the tube is closed; and

means for securing the tube closely around the proximal end of the nerve, wherein the securing means is provided by constructing the wall of the tube of a material having a thickness which provides both resiliency and renitency such that the tube will return to and maintain a longitudinally closed position after having been opened, thereby providing a close seal along the longitudinal slit when the tube is closed.

2. A nerve prosthesis as defined in claim 1 further comprising a coating applied to at least a portion of the exterior surface of the tube and wherein said coating terminates in the longitudinal flaps, said coating comprising a material which does not substantially adhere to body tissue surrounding the severed nerve so as to allow for slippage between the tube and the surrounding body tissue.

3. A nerve prosthesis as defined in claim 2 wherein the tube comprises polyurethane and the exterior coating comprises silicone.

4. A nerve prosthesis as defined in claim 1 wherein the renitent and resilient qualities of the tube are provided by constructing the thickness of the wall of the tube in the range of from about 10% to about 40% of the inner diameter of the tube.

5. A nerve prosthesis as defined in claim 1 wherein the tube is constructed in such a manner as to inhibit retraction of the proximal end of the nerve to not more than 0.5 millimeters from the distal end of the nerve.

6. A nerve prosthesis as defined in claim 5 wherein the tube is configured such that the first end of the tube is long enough to extend over the proximal end of the severed nerve by at least about 3 millimeters.

7. A nerve prosthesis as defined in claim 5 wherein the tube is configured such that the second end of the tube is long enough to extend over the distal end of the severed nerve by at least about 3-4 millimeters.

8. A nerve prosthesis as defined in claim 1 wherein the configuration of the tube is such that it is capable of maintaining the proximal end of the nerve in close proximity with the distal end of the nerve without suturing the nerve ends together.

9. A nerve prosthesis as defined in claim 1 wherein the first and second ends of the tube are slightly tapered.