Implantable medical electrical leads, kits, systems and methods of use thereof

1. A method of electrically stimulating the spinal cord with a plurality of directional stimulation electrodes on a plurality of electric stimulation leads, each of the electric stimulation leads having a distal end portion with a generally circular cross section on which one or more of the directional stimulation electrode(s) of the plurality are disposed, wherein said plurality of directional stimulation electrodes form an electrode array including at least first, second and third directional stimulation electrodes respectively disposed on first, second and third electric stimulation leads of the plurality of electric stimulation leads, and wherein each directional stimulation electrode of the plurality extends only around a portion of the circumference of the generally circular cross section of the distal end portion on which the directional stimulation electrode is disposed, the method comprising:

(a) implanting the plurality of electric stimulation leads in the epidural space of a patient with:

(1) the plurality of electric stimulation leads forming a lead array in the epidural space in which the third electric stimulation lead is disposed between the first and second electric stimulation leads, and

(2) the first, second and third directional stimulation electrodes being oriented at determined angular orientations relative to the spinal cord such that the third directional stimulation electrode generally faces the spinal cord while the first and the second directional stimulation electrodes are orientated at oblique angles relative to the third directional stimulation electrode; and

(b) programming the directional stimulation electrodes to create a tripole in which the first, second and third directional stimulation electrodes are active.

2. The method of claim 1 in which the step (b) of programming the directional stimulation electrodes to create a tripole in which the first, second and third directional stimulation electrodes are active includes:

independently varying the voltage or current amplitude of electric pulses overlapping in time on the first and second directional stimulation electrodes.

3. The method of claim 2 in which the step (b) of programming the directional stimulation electrodes to create a tripole in which the first, second and third directional stimulation electrodes are active further includes:

programming the first and second directional stimulation electrodes as anodes and the third directional stimulation electrode is programmed as a cathode.

4. The method of claim 1 in which the step (a) of implanting the plurality of electric stimulation leads in the epidural space of a patient further includes:

aligning the first, second and third directional stimulation electrodes generally in a direction transverse relative to the spinal cord.

5. The method of claim 1 wherein the first and second directional stimulation electrodes each only extends around less than half of the circumference of the distal ends of the first and second electric stimulation leads respectively, and the third directional stimulation electrode extends more than half of the circumference of the distal end of the third electric stimulation lead.

6. A method of electrically stimulating the spinal cord with first, second and third electric stimulation leads, each of the first, second and third electric stimulation leads having a distal end portion with a generally circular cross section and at least one directional stimulation electrode extending only around a portion of the circumference of the generally circular cross section of the distal end portion, the method comprising:

(a) implanting the first, second and third electric stimulation leads in the epidural space of a patient with:

(1) the first, second and third electric stimulation leads forming a lead array in the epidural space in which the third electric stimulation lead is disposed between the first and second electric stimulation leads, and

(2) the directional stimulation electrodes of each electric stimulation lead being oriented at determined angular orientations relative to the spinal cord such that the at least one directional stimulation electrode of the third electric stimulation lead is orientated to generally face the spinal cord and the directional stimulation electrodes of the first and second electric stimulation leads are orientated at oblique angles relative to the at least one directional stimulation electrode of the third electric stimulation lead; and

(b) programming the directional stimulation electrodes to create a tripole in which at least one electrode is active on each of the first, second and third electric stimulation leads wherein the directional stimulation electrodes programmed as active constitute a first active electrode on the first electric stimulation lead, a second active electrode on the second electric stimulation lead and a third active electrode on the third electric stimulation lead.

7. The method of claim 6 in which the step (b) of programming the directional stimulation electrodes to create a tripole in which at least one electrode is active on each of the first, second and third electric stimulation leads includes:

varying voltage or current amplitude of electric pulses overlapping in time on the first and second active stimulation electrodes independently of one another.

8. The method of claim 7 in which the step (b) of programming the directional stimulation electrodes to create a tripole in which at least one electrode is active on each of the first, second and third electric stimulation leads further includes:

programming the first and second active electrodes as anodes and the third active electrode is programmed as a cathode.

9. The method of claim 6 in which the step (a) of implanting the first, second and third electric stimulation leads in the epidural space of a patient further includes:

aligning the first, second and third active electrodes generally in a direction transverse relative to the spinal cord.

10. The method of claim 6 in which each of the directional stimulation electrodes of the first, second and third electric stimulation leads constitutes a ring electrodes which is shielded to provide electrical insulation and an exposed tissue-stimulation portion of the electrode extending around the portion of the circumference of the generally circular cross section of the distal end portion is exposed through a window that remains unshielded.

11. The method of claim 6 in which each of the directional stimulation electrodes of the first, second and third electric stimulation leads constitutes an arcuate member extending less than half of the circumference of the distal end portion of the first, second or third electric stimulation lead, respectively.

12. A method of electrically stimulating the spinal cord with first, second and third electric stimulation leads, each of the first, second and third electric stimulation leads having a distal end portion with a generally circular cross section on which one or more stimulation electrode(s) are disposed including first and second directional stimulation electrodes on the first and second electric stimulation leads, respectively, and a third direction stimulation electrode on the third electric stimulation lead, wherein each directional stimulation electrode is exposed for tissue stimulation only around a portion of the circumference of the circular cross section of the distal end portion on which the electrode is disposed, and wherein each of the first and second directional stimulation electrodes extends only less than half of the circumference of the circular cross section of the distal end portion on which the electrode is disposed, the method comprising:

(a) implanting the plurality of electric stimulation leads in the epidural space of a patient at determined angular orientations relative to the spinal cord with:

(1) the plurality of electric stimulation leads forming a lead array in the epidural space with the third stimulation lead disposed between the first and second stimulation lead, wherein the third directional stimulation electrode of the third stimulation lead is orientated to face the spinal cord, and

(2) the first and second directional stimulation electrodes being oriented at determined angular orientations relative to the spinal cord such that the first and second directional stimulation electrodes are orientated at oblique angles relative to the orientation of the third stimulation lead; and

(b) programming the stimulation electrodes to create a tripole in which the first, second and third stimulation electrodes are active.