Electrode array device configured for placement inside the dura for direct spinal cord stimulation

Patent metadata

Field	Value
Publication number	US-9364660-B2
Application number	US-201113885157-A
Country	US
Kind code	B2
Filing date	Nov 11, 2011
Priority date	Nov 11, 2010
Publication date	Jun 14, 2016
Grant date	Jun 14, 2016

Abstract

A method for treating intractable pain via electrical stimulation of the spinal cord. Remote, non-contact stimulation of a selected region of spinal cord is achieved by placement of a transceiver patch directly on the surface of that region of spinal cord, with said patch optionally being inductively coupled to a transmitter patch of similar size on either the outer or inner wall of the dura surrounding that region of the spinal cord. By inductively exchanging electrical power and signals between said transmitter and transceiver patches, and by carrying out the necessary electronic and stimulus signal distribution functions on the transceiver patch, the targeted dorsal column axons can be stimulated without the unintended stray stimulation of nearby dorsal rootlets. Novel configurations of a pliable surface-sheath and clamp or dentate ligament attachment features which realize undamaging attachment of the patch to the spinal cord are described.

First claim

What is claimed is:

1. A system for treating pain in a patient, comprising:
(1) an electrode assembly configured for intradural implantation, which includes:
(a) a compliant backing;
(b) a plurality of electrodes forming an array along a surface of the backing;
(c) a support structure configured to secure the electrodes directly in contact with the spinal cord; and

(2) circuitry configured for electrical coupling with the electrodes to deliver electrical through the electrodes to a targeted subregion of the spinal cord;
wherein the electrode assembly is configured to conform to the pial surface of the spinal cord of the patient, and has a sufficiently thin profile such that when the array of electrodes is placed against the pial surface, the CSF filled space is maintained, thereby separating the dura from the spinal cord, preventing mechanical constriction and obstruction of CSF flow between the electrode assembly and the dura; and
wherein the electrodes are arrayed on the backing so as to provide a sufficiently concentrated stimulus field such that electrical stimuli can be administered to the whole treatment zone from inside the dura without exciting dorsal nerve rootlets.

2. The system of claim 1 , wherein individual electrodes in the array are flexibly mounted to the backing by a soft resilient material, thereby allowing each electrode to float resiliently or move radially and/or laterally relative to the backing by a distance that is at least as large as pulsations of the surface of the spinal cord.

3. The system of claim 1 , wherein individual electrodes in the array are flexibly mounted to the backing by a soft resilient material such that the electrodes exert generally even pressure on the spinal cord, thereby serving as mechanical anchoring points for the electrode assembly.

4. The system of claim 1 , wherein individual electrodes in the array are attached to the compliant backing by way of a stand-off column.

5. The system of claim 1 , wherein the electrode assembly is 0.5 mm thin or less.

6. The system of claim 1 , further comprising a signal receiver disposed along the backing of the electrode assembly and configured to receive energy wirelessly, and a signal generator having a signal transmitter configured for transmitting energy to the electrodes from outside the patient's dura.

7. The system of claim 1 , further comprising a signal generator configured for transmitting energy to the array of electrodes from outside the patient's dura, and a conductor extendable through the patient's dura to couple the generator to the electrodes.

8. The system of claim 7 , further comprising a dura-traversing lead fitting that is configured to form a water-tight closure when the dura is closed around the conductor.

9. The system of claim 1 , wherein the backing of the electrode assembly contains electronic circuitry configured to prevent accidental delivery of excess voltages to the spinal cord of a patient during normal application of stimulus signals.

10. The system of claim 1 , wherein the electrodes are configured to penetrate into the spinal cord and activate neural motor pathways.

11. The system of claim 1 , wherein the support structure comprises flexible attachment arms extending from either side of the backing, thereby configuring the array of electrodes to wrap around and form a stable attachment with the spinal cord.

12. The system of claim 1 , wherein the support structure comprises left and right support features that extend laterally from the backing and are configured to pass from the spinal cord to the surrounding dura of the patient at positions that are adjacent to left and right dentate ligaments, thereby supporting the array of electrodes in contact with the spinal cord such that the array moves with the spinal cord when the spinal cord moves within the patient's dura.

13. The system of claim 1 , wherein the circuitry is configured and programmed for delivering electrical stimulation to target the subregion by activating selected combinations of the electrodes.

14. The system of claim 1 , wherein the circuitry is configured and programmed to drive individual electrodes selectively so as to stimulate programmably preselected target regions of the spinal cord.

15. A method of preparing a subject for treatment of pain, comprising:
obtaining a system comprising an electrode assembly and circuitry according to claim 1 ;
forming an opening in the dura surrounding the subject's spinal cord;
passing the electrode assembly through the opening and placing it so that the array of electrodes is in direct contact with the spinal cord at a position from which to deliver electrical stimuli to a targeted subregion of the spinal cord;
securing the electrode assembly so that:
(1) the CSF filled space is maintained, thereby separating the dura from the spinal cord, preventing mechanical constriction and obstruction of CSF flow between the electrode assembly and the dura; and
(2) the array stays in place against the spinal cord as the spinal cord moves inside the dura;

coupling the electrode assembly inside the dura to circuitry outside the dura through a lead fitting; and
closing the dura around the lead fitting so as to form a watertight closure.

16. A method of treating pain in a subject, comprising delivering electrical stimuli to a targeted subregion of the spinal cord of the subject by way of a system according to claim 1 that has been implanted in the spinal canal inside the dura of the subject so that the array of electrodes is placed and secured in direct contact with the subject's spinal cord and maintains its position as the spinal cord moves inside the dura.

17. The method of claim 16 , wherein the pain is associated in the subject with a musculo-skeletal disorder, a neoplasm, arthritic degeneration, a neurodegenerative disorder, or trauma.

18. A method of preparing a subject for treatment of pain, comprising:
obtaining a system comprising an electrode assembly and circuitry according to claim 1 ; and
implanting the electrode assembly inside the dura of the subject such that the electrodes in the array are placed in direct contact with the pial surface of the subject's spinal cord at a position from which to deliver electrical stimuli to a targeted subregion of the spinal cord; and
securing the electrode assembly in place so that:
(1) the CSF filled space is maintained, thereby separating the dura from the spinal cord, preventing mechanical constriction and obstruction of CSF flow between the electrode assembly and the dura; and
(2) the array stays in place against the spinal cord as the spinal cord moves inside the dura.

19. The method of claim 18 , further comprising coupling the electrode assembly with the circuitry, thereby configuring the electrodes for delivering the electrical stimuli to the targeted subregion.

20. A method of treating pain in a subject, comprising preparing the subject according to claim 19 , and then delivering electrical stimuli to the targeted subregion of the spinal cord through the electrodes of the electrode assembly, thereby treating the pain.

21. An electrode array configured for implanting inside the dura that surrounds a patient's spinal cord and for delivering electrical stimulation directly to the spinal cord, comprising:
(1) a curved backing having a curvature that is contoured to match the curvature of the spinal cord, and is sufficiently elastic to expand and contract with spinal cord movement; and
(2) a plurality of electrode

Assignees

• Howard Matthew
• Brennan Timothy
• Dalm Brian
• Utz Marcel
• Gillies George T
• Scott Steven
• Nelson Randall S
• Shurig Robert
• Univ Iowa Res Found
• Univ Virginia Patent Found

Inventors

• Howard Matthew
• Brennan Timothy
• Dalm Brian
• Utz Marcel
• Gillies George T
• Scott Steven
• Nelson Randall S
• Shurig Robert

Classifications

• A61N1/375 Primary

  Constructional arrangements, e.g. casings · CPC title

• A61N1/37514

  Brain implants · CPC title

• A61N1/372

  Arrangements in connection with the implantation of stimulators · CPC title

• A61N1/3787

  from an external energy source · CPC title

• A61N1/37518

  Anchoring of the implants, e.g. fixation · CPC title