IP Library › Granted Patent US 12,708,770
Granted Patent B2
US 12,708,770 · App. 18/355,126 · Granted Aug 18, 2026

Feed forward control system for a spinal cord stimulation system and method of use

Inventor: Erich W. Wolf, II (Lake Charles, LA)
Assignee: Wavegate Corporation
A61N1/36062A61B5/1116A61B5/686A61N1/0551A61N1/36139A61N1/36157A61B5/4561A61B5/4566A61B5/6867A61N1/025A61N1/36071
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Quick Facts
Patent No.
US 12,708,770
App. No.
18/355,126
Granted
Aug 18, 2026
Kind
B2
Abstract

The system incorporates a feed forward control system which automatically adjusts mean stimulation current to maintain consistent dosing of electrical current applied to the spinal cord despite motion of the spinal cord relative to the epidural electrode array. Optical boundary conditions are captured using a sample and hold circuit when the spinal cord is in its most dorsal position (supine patient position) and most ventral position (prone or sitting positions). Optimal mean stimulation current is manually set for these two ordinal positions during setup. During operation, the mean current is actively modulated by interpolating the mean current between the two current boundary conditions using a nominally inverse linear relation to the instantaneous optical reflectance which is bounded by the optical boundary conditions.

Claims (42)

1 . A system for stimulating a spinal cord of a patient comprising:

a controller, having a memory;

a reflectometer, operatively connected to the controller;

a stimulation electrode operatively connected to the controller; and

a set of instructions, resident in the memory that, when executed cause the system to perform the steps of:

storing a lower reflectometer current boundary and an upper stimulation current boundary corresponding to a patient prone position, wherein the patient prone position is any posture of the patient in which the stimulation electrode is implanted wherein the spinal cord is in its most ventral position and further away from the reflectometer;

storing an upper reflectometer current boundary and a lower stimulation current boundary corresponding to a patient supine position, wherein the patient supine position is any posture of the patient in which the stimulation electrode is implanted wherein the spinal cord is in its most dorsal position and nearest the reflectometer;

deriving a functional relationship between the lower reflectometer current boundary, the upper reflectometer current boundary, the lower stimulation current boundary and the upper stimulation current boundary;

deriving an adjusted stimulation current value by adjusting a stimulation current value based on the functional relationship and a reflectometer current signal;

sending a stimulation signal to the stimulation electrode based on the adjusted stimulation current value; and

directly applying the stimulation signal with the adjusted stimulation current value to a tissue of the patient.

2 . The system of claim 1 , wherein the functional relationship is linear.

3 . The system of claim 1 , wherein the set of instructions further comprises instructions that when executed cause the system to perform the step of:

clipping the reflectometer current signal at the upper reflectometer current boundary and the lower reflectometer current boundary, thereby maintaining the stimulation signal between the lower stimulation current boundary and the upper stimulation current boundary.

4 . The system of claim 1 , wherein the set of instructions further comprises instructions that when executed cause the system to perform the step of:

monitoring a processor interrupt condition for one of the upper reflectometer current boundary and the lower reflectometer current boundary.

5 . The system of claim 4 , wherein the set of instructions further comprises instructions that when executed cause the system to perform the step of:

changing the stimulation current value upon an occurrence of the processor interrupt condition.

6 . The system of claim 1 , wherein the set of instructions further comprises instructions that when executed cause the system to perform the step of:

setting an optical threshold comparator of the controller to respond to a range in the reflectometer current signal.

7 . The system of claim 6 , wherein the range is associated with a minimal difference in the stimulation signal.

8 . A method for stimulating a spinal cord of a patient, the method further comprising:

providing a controller, having a memory;

providing a reflectometer, operatively connected to the controller;

providing a stimulation electrode operatively connected to the controller; and

providing a set of instructions, resident in the memory that, when executed cause the controller to perform the steps of:

storing a lower reflectometer current boundary and an upper stimulation current boundary corresponding to a patient prone position, wherein the patient prone position is any posture of the patient in which the stimulation electrode is implanted wherein the spinal cord is in its most ventral position and further away from the reflectometer;

storing an upper reflectometer current boundary and a lower stimulation current boundary corresponding to a patient supine position, wherein the patient supine position is any posture of the patient in which the stimulation electrode is implanted wherein the spinal cord is in its most dorsal position and nearest the reflectometer;

deriving a functional relationship between the lower reflectometer current boundary, the upper reflectometer current boundary, the lower stimulation current boundary and the upper stimulation current boundary;

deriving an adjusted stimulation current value by adjusting a stimulation current value based on the functional relationship and a reflectometer current signal;

sending a stimulation signal to the stimulation electrode based on the adjusted stimulation current value; and

directly applying the stimulation signal with the adjusted stimulation current value to a tissue of the patient.

9 . The method of claim 8 , wherein the functional relationship is linear.

10 . The method of claim 8 , wherein the set of instructions further comprises instructions that when executed further cause the controller to perform the steps of:

clipping the reflectometer current signal at one of the upper reflectometer current boundary and the lower reflectometer current boundary.

11 . The method of claim 8 , wherein the set of instructions further comprises instructions that when executed further cause the controller to perform the step of:

monitoring a processor interrupt condition for one of the upper reflectometer current boundary and the lower reflectometer current boundary.

12 . The method of claim 11 , wherein the set of instructions further comprises instructions that when executed further cause the controller to perform the step of:

changing the stimulation current value upon an occurrence of the processor interrupt condition.

13 . The method of claim 8 , wherein the set of instructions further comprises instructions that when executed further cause the controller to perform the step of:

setting an optical threshold comparator of the controller to respond to a range in the reflectometer current signal.

14 . The method of claim 13 , wherein the range is associated with a minimal difference in the stimulation signal.