Percutaneously inserted spinal cord stimulation lead

• US 4,044,774 A
• Filed: 02/23/1976
• Issued: 08/30/1977
• Est. Priority Date: 02/23/1976
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Zytkovicz, Duane J., Corbin, Terry
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Cohen, Lee S.
• Application Number:
  US05/660,353
• Time in Patent Office: 554 Days
• Field of Search: 128/404, 128/418, 128/419 C, 128/419 E, 128/419 F, 128/419 P, 128/419 R
• US Class Current: 607/117
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes

Abstract

A lead is disclosed for being inserted within a human or animal body for applying electrical stimulation to the spinal cord of the recipient, whereby selected pain is effectively relieved by the application of an electrical signal of selected frequency, pulsewidth and amplitude to the lead. In particular, the lead comprises a spherically-shaped, distal electrode adapted to be disposed near a selected segment of the spinal cord whereby maximum stimulation may be applied to the afferent nerves passing therethrough, a first conductor taking the form of a helically-wound coil extending from the distal electrode to a first tubular contact, and a second conductor disposed axially of the first-mentioned coil and forming an extension extending beyond the first-mentioned contact and terminated in a second tubular contact.

Claims

1. A lead adapted to be attached to and extended between first and second sources of electrical stimulation and animal tissue to conduct and apply such stimulation to the tissue, comprising:

(a) a stimulation electrode of an electrically conductive material substantially inert to body fluids and tissues;

(b) a first conductor having a distal end electrically connected to said stimulation electrode and extending therefrom a first distance along said lead to a proximal end thereof;

(c) a first electrical contact electrically connected to said proximal end of said first conductor, and adapted to be connected to the first source of stimulation to be applied along said first conductor to said stimulation electrode for stimulating the animal tissue;

(d) a second conductor having a distal end electrically connected to said stimulation electrode and extending a second distance along said lead to a proximal end of said second conductor, said second distance being greater than said first distance;

(e) a second electrical contact electrically connected to said proximal end of said second conductor and adapted to be connected to the second source of stimulation whereby electrical stimulation may be applied through said second conductor to said stimulation electrode; and

(f) a sheath of an electrically insulating material substantially inert to body fluids and tissues and covering said first and second conductors between said stimulation electrode and said first and second contacts, said second conductor and said sheath covering said second conductor between said first and second contacts being of a reduced dimension, whereby said second conductor may be readily severed and removed from said lead.

2. The lead as claimed in claim 1, wherein said first conductor is formed as a coil disposed within said sheath.

3. The lead as claimed in claim 1, wherein said first contact is of a tubular configuration and is disposed about said first conductor and crimped thereto.

4. The lead as claimed in claim 1, wherein said first contact is normally covered with an insulating material readily penetrable to facilitate electrical connection of said first contact to the first source of stimulation.

5. The lead as claimed in claim 1, wherein there is included a second stimulation electrode spaced remotely from and insulated from said first stimulation electrode, a third conductor having a distal end connected to said second stimulation electrode and disposed along the length of said lead a third distance less than said first distance to a proximal end, a third contact of an electrically conductive material substantially inert to said body fluids and tissues and connected to said proximal end of said third conductor, a fourth conductor having a distal end electrically connected to said second electrode and disposed along the length of said lead to a proximal end a fourth distance greater than said third distance, and a fourth contact of an electrically conductive material substantially inert to body fluids and tissues and electrically connected to said proximal end of said fourth conductor whereby electrical stimulation may be applied through said fourth conductor to said second stimulation electrode.

6. Medical apparatus implantable in the body of an animal, comprising:

(a) a stimulation electrode of an electrically conductive material substantially inert to body fluids and tissues;

(b) a first conductor having a first, distal end electrically connected to said stimulation electrode and extending therefrom a first distance along said medical apparatus to a second proximal end thereof;

(c) a first electrical contact electrically connected to said second, proximal end of said first conductor, and adapted to be connected to apply stimulation along said first conductor to said electrode for stimulating nerve tissue of the animal;

(d) a second conductor having a first, distal end electrically connected to said electrode and extending a second distance greater than said first distance and having a second, proximal end;

(e) a second electrical contact electrically connected to said second, proximal end of said second conductor and adapted to be connected to apply stimulation through said second conductor to said stimulation electrode; and

(f) a first sheath of an electrically insulating material substantially inert to body fluids and tissues and covering said first and second conductors between said stimulation electrode, and said first contact, and a second sheath of an electrically insulating material substantially inert to body fluids and tissues and at least covering said second conductor between said first contact and said second contact, said second conductor and second sheath being of a reduced dimension, whereby it may be readily severed and removed from said medical apparatus.

7. Medical apparatus as claimed in claim 6, wherein said first conductor is formed as a coil disposed about said second sheath, said second sheath extending along substantially the entire length of said second conductor.

8. Medical apparatus as claimed in claim 6, wherein said first contact is of a tubular configuration and is disposed about said first conductor and crimped thereto.

9. The medical apparatus as claimed in claim 6, wherein said first contact is normally covered with an insulating material readily penetrable to facilitate electrical connection of said first contact to the electrical stimulation.

10. Medical apparatus as claimed in claim 6, wherein there is included a second stimulation electrode spaced remotely from and insulated from said first stimulation electrode, a third conductor having a distal end connected to said second stimulation electrode and disposed along the length of said medical apparatus a third distance less than said first distance to a proximal end, a third contact of an electrically conductive material substantially inert to said body fluids and tissues and connected to said proximal end of said third conductor, a fourth conductor having a distal end electrically connected to said second electrode and disposed along said medical apparatus a fourth distance greater than said third distance to a proximal end, and a fourth contact of an electrically conductive material substantially inert to body fluids and tissues and electrically connected to said proximal end of said fourth conductor whereby electrical stimulation may be applied through said fourth conductor to said second stimulation electrode.

11. Apparatus for electrically stimulating animal tissue of the type including a generator for producing chronic electrical stimulation and a lead connected to said generator and comprising a first, permanent conductor having a proximal end including first contact means and a distal end including a stimulation electrode, said first contact means connected to said generator to conduct via said first conductor the chronic electrical stimulation therethrough to its distal end connected to said stimulation electrode, whereby selected, remote animal tissue is stimulated, said lead being constructed of materials substantially inert to body fluids and tissues and further comprising:

(a) means for percutaneously admitting said lead into the body and for advancing said electrode into contact with the selected animal tissue;

(b) second contact means electrically connected to said electrode of said lead adapted to be connected to a screening generator on advancement of said electrode into contact with the selected animal tissue for eliciting a tissue response to the electrical stimulation impulses; and

(c) a severable extension conductor extending between said stimulation electrode and said second contact means effecting the electrical connection therebetween and facilitating the application of screening stimulation to the selected animal tissue, said severable extension conductor having a length greater than that of said first permanent conductor.

12. The apparatus as claimed in claim 11, wherein said percutaneous admitting means comprises a tubular needle into which said lead extends.

13. The apparatus as claimed in claim 11, wherein said permanent conductor is formed as a coil disposed within an insulating sheath extending between said stimulation electrode and said first contact means.

14. The apparatus as claimed in claim 11, wherein said first contact means is of a tubular configuration and is disposed about said permanent conductor and crimped thereto.

15. The apparatus as claimed in claim 11, wherein said first contact means is normally covered with an insulating material readily penetrable to facilitate electrical connection of said first contact means to the source of chronic stimulation.

16. Apparatus for electrically stimulating selected segements of a spinal cord, and including a lead having distal and proximal ends and applying electrical stimulation to the selected segments, and operative in a first, screening mode, wherein said lead is connected to a screening electrical generator for applying screening stimulation to said electrode, and in a second mode wherein said lead is connected to a chronic electrical generator for applying chronic electrical stimulation to said electrode, said lead comprising:

(a) a stimulating electrode connected to said distal end of said lead for applying electrical stimulation to the selected segments;

(b) first contact means disposed at said proximal end of said lead and connected to the chronic electrical generator;

(c) a first permanent conductor extending between said electrode and said first contact means for effecting the electrical connection therebetween and facilitating the chronic stimulation of the selected segments;

(d) second contact means adapted to be connected to the screening electrical generator; and

(e) a severable extension conductor extending between said electrode and said second contact means for effecting the electrical connection therebetween and facilitating the screening stimulation of the selected segments, said severable extension conductor having a length greater than that of said first permanent conductor.

17. The apparatus as claimed in claim 16, wherein said permanent conductor is formed as a coil disposed within an insulating sheath of a material substantially inert to body fluid and tissues, said sheath covering said permanent and severable conductors between said electrode and said first contact means.

18. The apparatus as claimed in claim 16, wherein said first contact means is of a tubular configuration and is disposed about said permanent conductor and crimped thereto.

19. The apparatus as claimed in claim 16, wherein said first contact means is normally covered with an insulating material readily penetrable to facilitate electrical connection of said first contact means to the source of chronic stimulation.

20. A lead adapted to apply electrical stimulation to selected animal tissue, comprising:

(a) a stimulation electrode of an electrically conductive material substantially inert to body fluids and tissues;

(b) a first conductor having a distal end electrically connected to said stimulation electrode and extending therefrom a first distance along said lead to a proximal end thereof;

(c) a first electrical contact electrically connected to said proximal end of said first conductor, and adapted to be connected to the first source of stimulation to be applied along said first conductor to said stimulation electrode for stimulating the selected animal tissue;

(d) a second conductor having a distal end electrically connected to said stimulation electrode and extending a second distance along said lead to a proximal end of said second conductor, said second distance being greater than said first distance;

(e) a second electrical contact electrically connected to said proximal end of said second conductor and adapted to be connected to the second source of stimulation whereby electrical stimulation may be applied through said second conductor to said stimulation electrode;

(f) a first sheath of an electrically insulating material substantially inert to body fluids and tissues and covering said first conductor between said stimulation electrode and said first contact;

(g) a second stimulation electrode spaced remotely from and insulated from said first stimulation electrode;

(h) a third conductor having a distal end connected to said second stimulation electrode and disposed along the length of said lead a third distance less than said first distance to a proximal end;

i. a third contact of an electrically conductive material substantially inert to said body fluids and tissues and connected to said proximal end of said third conductor;

(j) a fourth conductor having a distal end electrically connected to said second electrode and disposed along the length of said lead a fourth distance greater than said third distance to a proximal end;

(k) a fourth contact of an electrically conductive material substantially inert to body fluids and tissues and electrically connected to said proximal end of said fourth conductor whereby electrical stimulation may be applied through said fourth conductor to said second stimulation electrode; and

(1) second and third sheaths of an electrically insulating material substantially inert to body fluids and tissues and covering, respectively, said second and fourth conductors.

21. The lead as claimed in claim 20, wherein each of said second and fourth conductors and said second and third sheaths are of a reduced dimension, whereby said second and fourth conductors may be readily severed and removed from said lead.