Electrode array, a lead paddle and a neuromodulation system

Abstract

The present invention relates to an electrode array for neuromodulation, comprising a first electrode section with more than two electrodes being arranged parallel and densely packed in the first electrode section, further comprising a second electrode section with more electrodes than in the first electrode section, the electrodes in the second electrode section being arranged symmetrically with respect to the longitudinal axis and transversal offset to each other. Furthermore, the present invention relates to a lead paddle and a neuromodulation system.

Claims

1. An electrode array for neuromodulation, the array defined by a longitudinal axis and a radial axis perpendicular to the longitudinal axis, the array consisting essentially of: a first electrode section with more than two electrodes arranged in parallel along a common axis parallel to the longitudinal axis and densely packed in the first electrode section, wherein the first electrode section comprises at least three columns aligned with the longitudinal axis and only one radial row along the radial axis; and a second electrode section with more electrodes than the first electrode section, the electrodes in the second electrode section arranged symmetrically with respect to the longitudinal axis, and with a transversal offset relative to each other; wherein the first electrode section and the second electrode section are separated by a gap having a length in a range of 100-160% of a length of an electrode of the first or second electrode sections; and the electrodes in the first electrode section are spaced apart from adjacent electrodes by a distance that is less than a distance between adjacent electrodes of the second electrode section.

2. The electrode array according to claim 1, wherein the first electrode section is arranged at a proximal end of the electrode array and/or the second electrode section is arranged at a distal end of the electrode array.

3. The electrode array according to claim 1, wherein the electrodes in the first electrode section are identical to the electrodes in the second electrode section.

4. The electrode array according to claim 3, wherein at least one electrode has a length that is 2.0-4.0 times of a width.

5. The electrode array according to claim 3, wherein all electrodes of the first and second electrode sections have a common orientation, the common orientation parallel to the longitudinal axis.

6. The electrode array according to claim 1, wherein the electrode array has a length that is of 8-14 times of a length of an electrode of the first or second electrode sections.

7. The electrode array according to claim 1, wherein the first electrode section is symmetrical with respect to the longitudinal axis and with respect to the radial axis in the first electrode section, and wherein the second electrode section is symmetrical with respect to the longitudinal axis and asymmetrical with respect to the radial axis in the section electrode section.

8. The electrode array according to claim 7, wherein the second electrode section comprises at least three columns aligned with the longitudinal axis and more than five radial rows.

9. The electrode array according to claim 1, wherein a distance between electrodes of the first electrode section is less than a width of an electrode of the first or second electrode sections, the distance chosen in a range of 50% to 95% of the width of the electrode of the first or second electrode sections.

10. The electrode array according to claim 1, wherein in the second electrode section, the electrodes in neighboring columns are arranged with a transversal offset relative to each other.

11. The electrode array according to claim 10, wherein in the second electrode section, a distance between neighboring electrodes arranged in a common column is in a range of 135% to 155% of the length of the electrode.

12. The electrode array according to claim 1, wherein a total number of electrodes in the electrode array is 16 electrodes.

13. The electrode array according to claim 1, wherein the more than two electrodes of the first electrode section are arranged in columns along the longitudinal axis, and the electrodes of the second electrode section are arranged in a number of columns less than the columns of the first electrode section.

14. The system of claim 13, wherein a portion of the electrodes of the second electrode section are positioned on the longitudinal axis of the electrode array.

15. A lead paddle comprising at least one electrode array, the at least one electrode array defined by a longitudinal axis and a radial axis perpendicular to the longitudinal axis, the at least one electrode array consisting essentially of: a first electrode section with a first number of electrodes arranged in parallel columns, wherein the first electrode section comprises at least three columns aligned with the longitudinal axis and only one radial row along the radial axis; and a second electrode section with a second number of electrodes, more than the first number, arranged symmetrically with respect to the longitudinal axis, and with a transversal offset relative to each other, wherein the second number of electrodes are arranged in a number of columns less than the parallel columns of the first electrode section.

16. A neuromodulation system comprising: at least one lead paddle; and at least one electrode array defined by a longitudinal axis and a radial axis perpendicular to the longitudinal axis, the at least one electrode array consisting essentially of: a first electrode section with a first number of electrodes arranged in parallel, wherein: the first electrode section comprises at least three columns aligned with the longitudinal axis and only one radial row along the radial axis; and a second electrode section with a second number of electrodes, more than the first number, arranged symmetrically with respect to the longitudinal axis, and with a transversal offset relative to each other, wherein a portion of the second number of electrodes lies on the longitudinal axis.

17. The system of claim 16, wherein electrodes of the first and second electrode sections have a common orientation, parallel to the longitudinal axis of the electrode array.

18. The system of claim 17, wherein the width and length of the electrodes of the first electrode section are identical to the width and length of the electrodes of the second electrode section.

19. The system of claim 18, wherein the second number of electrodes of the second electrode section are arranged in parallel columns, the electrodes in neighboring columns arranged with a transversal offset relative to each other.

20. The system of claim 18, wherein a distance between the electrodes of the first electrode section is less than the width of the electrode.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further details and advantages of the present invention shall now be disclosed in connection with the drawings.

(2) It is shown in

(3) FIG. 1 a view from above of a possible embodiment of an electrode array according to the present invention for a lead paddle and a neuromodulation system according to the present invention;

(4) FIG. 2 a side view of the lead paddle and the electrode array according to FIG. 1;

(5) FIG. 3 cutaway drawing through the first section of the lead paddle and the electrode array according to FIG. 1;

(6) FIG. 4 a schematical drawing of the spinal cord with the embodiment of the lead paddle of FIG. 1;

(7) FIG. 5 the lead paddle according to FIG. 1 with further details.

(8) It will be appreciated that FIGS. 1-5 show example configurations with relative positioning of the various components. Further, the components are shown to scale. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elements shown above/below one another, at opposite sides to one another, or to the left/right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a “top” of the component and a bottommost element or point of the element may be referred to as a “bottom” of the component, in at least one example. As used herein, top/bottom, upper/lower, above/below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example.

DETAILED DESCRIPTION

(9) FIG. 1 shows a view from above of a possible embodiment of an electrode array 5 according to the present invention for a lead paddle 10 and a neuromodulation system 100 according to the present invention.

(10) For better orientation in FIG. 1, a longitudinal axis shall be understood as being aligned (i.e. identical or parallel to) the longitudinal direction L.

(11) A radial axis shall be understood as being aligned (i.e. identical or parallel to) the radial direction R.

(12) The lead paddle 10 comprises a lead paddle body 11 and comprises two guiding channels 12.

(13) The two guiding channels 12 are embedded in the lead paddle body 11.

(14) The lead paddle body 11 may be made of a medical grade material, such as a medical grade polymer. In particular, a medical grade silicone or the like may be used.

(15) The guiding channels 12 extend over more than half of the length of the length of the lead paddle 10.

(16) Especially, the guiding channels 12 extend over more than a half, for example, 80% of the length of the lead paddle 10.

(17) In particular, the guiding channels 12 are arranged along the outer edge region 14 of the lead paddle 10.

(18) In particular, the guiding channels 12 are arranged parallel to the longitudinal edge 16 of the lead paddle 10.

(19) The lead paddle 10 comprises a plurality of electrodes 18 forming the electrode array 5.

(20) Here, in the shown embodiment 16 electrodes 18 are provided.

(21) The electrodes 18 are embedded in the body of the lead paddle 10.

(22) Each specific electrode 18 has a respective denotation “E”, in combination with a number “n”, with “n” being an integer between 1 to 16.

(23) The shape of the electrodes 18 is rectangular.

(24) All electrodes 18 have the identical form. The shape of all electrodes is more or less identical. Here the electrodes 18 are all identical in their form.

(25) The electrodes 18 have a length 1 that is 2.0-4.0 times of the width w, especially 2.5-3.0 times of the width. Here they have a length that is approx. 2.6 times of the width to form an elongate shaped rectangular electrode form.

(26) Generally speaking, the form of one or more electrodes can be designed differently. In particular, they can be oval, round, square, diamond shape, trapezoidal or the like.

(27) The electrodes 18 form the electrode array 5 for neurostimulation.

(28) The electrode array 5 has a length that is of 8-14 times of the length of an electrode, here in the shown embodiment approximately 12 times of the length of an electrode 18.

(29) All electrodes 18 have the same orientation. In particular, all electrodes 18 have an orientation parallel to the longitudinal axis of the electrode array 5.

(30) The electrode array 5 comprises a first electrode section S1 with four electrodes 18.

(31) The electrodes 18, here the electrodes E5, E6, E15 and E16 of the first electrode section S1 are arranged parallel and densely packed in the first electrode section S1.

(32) The first electrode section S1 is arranged at the proximal end P of the lead paddle 10.

(33) The first electrode section S1 comprises here four columns C01, C02, C03, C04 aligned with the longitudinal axis and only one radial row R0 along the radial axis in this first electrode section S1.

(34) The distance between electrodes 18 of the first electrode section S1 is less than the width w of an electrode 18 chosen in the range of approx. 50% to 95% of the width of an electrode 18 and here chosen at approx. 55-75% of the width of an electrode 18.

(35) A second electrode section S2 is arranged at the distal end D, i.e. the section orientated to the tip end 17 of the lead paddle 10.

(36) The first electrode section S1 and the second electrode section S2 are separated by a gap G that is larger than the length 1 of an electrode 18.

(37) Here, the length 12 of the gap G is chosen in a range of approx. 100-150% of the length of an electrode 18.

(38) In the second electrode section S2 more electrodes 18 than in the first electrode section S1 are provided, i.e. electrodes E1-E4, E7-E10 and E11-E14.

(39) The electrodes 18 in the second electrode section S2 are arranged symmetrically with respect to the longitudinal direction L and with transversal offset to each other.

(40) The second electrode section S2 comprises at least three columns C1, C2, C3 aligned with the longitudinal axis and eight rows R1, R2, R3, R4, R5, R6, R7, R8.

(41) In the second electrode section S2 the distance between neighboring electrodes 18 arranged in the same column C1, C2, C3 is chosen in the range of 135% to 155% of the length of an electrode 18, here in the range of 140% to 150% of the length 1 of an electrode 18.

(42) Also, in the second electrode section S2 the distance between neighboring rows R1, R2, R3, R4, R5, R6, R7, R8 is chosen in the range of 130% to 150% of the width w of an electrode 18, here in the range of 145% to 155% of the width w of an electrode 18.

(43) The arrangement of the electrodes 18 is also such that some electrodes are offset to each other.

(44) Here, in the second electrode section S2 the electrodes 18 in neighboring columns C1 to C2 and C2 to C3 are arranged relative to each other with a transversal offset.

(45) So and as clearly can be seen from e.g. FIG. 1, the electrode array 5 comprises a longitudinal axis in the direction of the longitudinal orientation of the electrodes 18, wherein the first electrode section S1 is symmetrical with respect to the longitudinal axis and with respect to a radial axis in the first electrode section S1 perpendicular to the longitudinal axis and the second electrode section S2 is symmetrical with respect to the longitudinal axis and asymmetrical with respect to a radial axis in the second electrode section S2 perpendicular to the longitudinal axis.

(46) The electrodes 18 of the lead paddle 10 are connected to lead bodies 20.

(47) The lead bodies 20 are connected to a connection portion 20a on the upper side 10a of the lead paddle 10.

(48) This connection portion 20a is on the opposite side of the contact side 10b of the lead paddle 10, that is configured and arranged to get in contact with the tissue to be stimulated, i.e. here the spinal cord of the patient.

(49) Furthermore, the connection portion 20a is arranged centric with regard to the axial axis of the lead paddle 10. Moreover, the connection position 20a is positioned with an offset d to the edge of the proximal end 10c of the lead paddle 10.

(50) As the connection portion 20a of the lead bodies 20 is not directly arranged at the outer edge of the lead paddle 10, the deployment and positioning of the lead paddle 10 is enhanced.

(51) In particular, the offset d helps that by means of the lead bodies 20 the lead paddle 10 may be moved back and forth and also to the left and right and vice versa even after deployment in the spinal canal. As the lead bodies are arranged on the upper side with an offset to the edge, the proximal edge of the lead paddle is free and especially a movement in the proximal direction is not obstructed by the lead bodies.

(52) As can be further seen in FIG. 1, the lead bodies 20 can be provided with anchoring sleeves 22.

(53) The anchoring sleeves 22 are attached to the outer side of the lead body 20.

(54) Furthermore, the anchoring sleeves 22 are provided with pins 24 or so-called anchor bumps 24, which extend radially from the outer side of the anchoring sleeve 22.

(55) FIG. 2 shows a side view of the lead paddle and the electrode array according to FIG. 1.

(56) As can be seen in FIG. 2, the electrodes 18 protrude out of the surface of the contact side 10b.

(57) FIG. 3 shows cutaway drawing through the first section of the lead paddle and the electrode array according to FIG. 1.

(58) On the upper side 10a the connection portions 20a of the lead bodies 20 can be seen.

(59) Due to the arrangement of the electrodes 18 and the spacing between the electrodes 18, the form of the electrodes 18, the lead paddle body 11 and thus the lead paddle 10 comprises axial stiffness in the longitudinal direction L and radial flexibility in the radial direction R.

(60) So, it is generally possible that even without a stylet and by means of the lead bodies 20 the lead paddle 10 can be inserted into the spinal channel. For such an insertion axial stiffness is necessary to avoid bending in axial direction, whereas (slight) bending in the radial direction is wanted to adapt to the anatomical structures at the implantation site in the spinal channel.

(61) The first electrode section S1 and the second electrode section S2 provide two different means for specifically evoking targeted pools of motor neurons.

(62) FIG. 4 shows a schematical drawing of the spinal column 200 and the spinal cord 210 with the embodiment of the lead paddle 10 with the electrode array 5 as described above.

(63) By means of the increased density of electrodes 18 in the first electrode section S1, e.g. positioned in an application for spinal cord stimulation above the sacral level of the spinal cord 210 in spinal cord stimulation as shown in FIG. 4, a current steering possibility may be provided to enhance stimulation specificity. In particular, a so-called electrode belt is established with the four electrodes 18 (i.e. electrodes E5, E6, E15, E16) being arranged parallel and densely packed in the first electrode section S1.

(64) In FIG. 4 it can been seen that dorsal roots enter the spinal cord in their respective segment (i.e. C1 root enters at C1 spinal segment). The exit point of the vertebrate column for lumbo-sacral roots is located rather far apart of their respective entry point in the spinal cord. Especially, lumbar and sacral roots overlay each other like a “spaghetti bag” around the conus medullaris region.

(65) From this anatomical structure and the needs for stimulation of these anatomical structures the following specific points are addressed by the electrode array 5 of the present invention:

(66) The stimulation with an electrode belt allows a well-defined (current steering) stimulation at the sacral level can potentially target any desired spinal segment located above (“belt array” strategy).

(67) The “standard” regular paddle design configuration in the second electrode section S2 is provided with regularly spaced electrodes for targeting dorsal roots at their entry point in spinal segments. This is based on the finding that a regularly spaced electrode array would work well in the cervical area to specifically address individual spinal segments, but that this specificity will deteriorate when sliding the array toward sacral region. Yet, it will still quite sufficient for upper lumbar segments.

(68) FIG. 5 shows the lead paddle 10 with the electrode array 5 according to FIG. 1 with further details.

(69) In particular, FIG. 5 shows in greater detail the dimensions and the lead paddle 10 with the electrode array 5 with example values for distances.

(70) Inter alia, the distance E between outermost edges of the electrode array (width) w1 is approx. 11.5 mm, distance F between outermost edges of the electrode array (length) l1 is approx. 65 mm (cf. also FIG. 2), distance H between the right outermost edges of two neighboring electrodes 18 is approx. 3.15 mm, distance I between proximal edge of section S1 is approx. 13.25 mm, distance J between proximal edge from R1 to R2 is approx. 6.7 mm, and distance K from longitudinal right edge of electrode in C2 to right outer longitudinal edge of the lead paddle 10 is approx. 6 mm.

(71) The overall dimensions/size of one electrode 18 is approx. 2×5.5 mm with 0.25 mm. In the shown embodiment, a minimum exposed electrode surface to tissue of at least 10 mm.sup.2 was required and is reached with this setup, as the exposed electrode surface of an electrode 18 is approx. 11 mm.sup.2.

(72) TABLE-US-00001 REFERENCES  5 electrode array  10 lead paddle  10a upper side  10b contact side  10c proximal end  11 lead paddle body  12 guiding channel  14 outer edge region  16 longitudinal edge  17 tip end  18 electrodes  20 lead body  20a connection portion  22 anchoring sleeves  24 pins 100 neuromodulation system 200 spinal column 210 spinal cord d offset D distal end E distance between outermost edges of the electrode array (width) F distance between outermost edges of the electrode array (length) G gap H distance H between the right outermost edges of two neighboring electrodes in section S1 I distance between proximal edge of section S1 J distance between proximal edge from R1 to R2 K distance from longitudinal right edge of electrode in C2 to right outer longitudinal edge of the lead paddle L longitudinal direction P proximal end R radial direction l length of electrode w width of electrode l1 length of electrode array w1 width of electrode array l2 length of gap C01 column in first electrode section C02 column in first electrode section C03 column in first electrode section C04 Column in first electrode section R0 row in first electrode section C1 column in second electrode section C2 column in second electrode section C3 column in second electrode section R1 row in second electrode section R2 row in second electrode section R3 row in second electrode section R4 row in second electrode section R5 row in second electrode section R6 row in second electrode section R7 row in second electrode section R8 row in second electrode section S1 first electrode section S2 second electrode section