Apparatus and method for determining the relative position and orientation of neurostimulation leads
First Claim
1. A method for determining the relative lead position of multipolar leads in a multi-lead configuration comprising measuring impedance vectors between electrodes;
- and inferring the relative position of the lead by the relative minima and maxima of the impedance values.
2 Assignments
0 Petitions
Accused Products
Abstract
Interelectrode impedance or electric field potential measurements are used to determine the relative orientation of one lead to other leads in the spinal column or other body/tissue location. Interelectrode impedance is determined by measuring impedance vectors. The value of the impedance vector is due primarily to the electrode-electrolyte interface, and the bulk impedance between the electrodes. The bulk impedance between the electrodes is, in turn, made up of (1) the impedance of the tissue adjacent to the electrodes, and (2) the impedance of the tissue between the electrodes. In one embodiment, the present invention makes both monopolar and bipolar impedance measurements, and then corrects the bipolar impedance measurements using the monopolar measurements to eliminate the effect of the impedance of the tissue adjacent the electrodes. The orientation and position of the leads may be inferred from the relative minima of the corrected bipolar impedance values. These corrected impedance values may also be mapped and stored to facilitate a comparison with subsequent corrected impedance measurement values. Such comparison allows a determination to be made as to whether the lead position and/or orientation has changed appreciably over time. In another embodiment, one or more electrodes are stimulated and the resulting electric field potential on the non-stimulated electrodes is measured. Such field potential measurements provide an indication of the relative orientation of the electrodes. Once known, the relative orientation may be used to track lead migration, to setup stimulation configurations and parameters for nominal stimulation and/or navigation. Also, such measurements allow automatic adjustment of stimulation energy to a previously-defined optimal potential field in the case of lead migration or postural changes.
-
Citations
26 Claims
-
1. A method for determining the relative lead position of multipolar leads in a multi-lead configuration comprising
measuring impedance vectors between electrodes; - and
inferring the relative position of the lead by the relative minima and maxima of the impedance values. - View Dependent Claims (2, 3, 4, 5)
- and
-
6. A method for determining whether the relative position of electrodes used by a neurostimulation system has changed, the method comprising steps for:
-
(a) applying a stimulus to a selected group of the electrodes;
(b) measuring the electric field at the electrodes not included in the group of electrodes to which the stimulus is applied;
(c) repeating steps (a) and (b) over time and determining if changes in the measured electric field have occurred;
(d) analyzing the changes in the electric field to determine whether changes in the relative position of the electrodes has occurred. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A method for determining the relative position of electrodes used by a neurostimulation system, the method comprising steps for:
-
(a) applying a stimulus to a selected group of the electrodes;
(b) measuring the electric field potential at the electrodes not included in the group of electrodes to which the stimulus is applied;
(c) analyzing the measured electric field potential at each electrode relative to the measured electric field potential at other electrodes to determine the position of the electrodes relative to each other. - View Dependent Claims (20, 21, 22, 23)
-
-
24. An apparatus for determining the relative position or orientation of electrodes carried on neurostimulation leads, comprising:
-
a multiplicity of implantable electrodes;
means for applying a stimulus to a selected group of the multiplicity of electrodes;
means for measuring the electric field at the electrodes not included in the group of electrodes to which the stimulus is applied;
means for analyzing the measured electric field to determine the relative position or orientation of the electrodes. - View Dependent Claims (25, 26)
-
Specification