MEDICAL ELECTRODE DEVICE FOR IMPLANTATION INTO A PATIENT

Abstract

A medical electrode device for implantation comprises a carrier formed from an electrically insulating material and defining a surface extending along a plane of extension, and at least one electrode arranged on the carrier for emitting an electrical stimulation signal and/or receiving an electrical sense signal. The at least one electrode comprises first and section wall sections. Said first wall section, in a cross-section along a cross-sectional plane perpendicular to said plane of extension, extends straight along a perpendicular direction with respect to said plane of extension or at an oblique angle with respect to said perpendicular direction, the first wall section in contact with the carrier electrically insulating material. Said second wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, adjoins said first wall section and is curved, the second wall section not in contact with the carrier electrically insulating material.

Claims

1. A medical electrode device for implantation into a patient, comprising: a carrier element being formed from an electrically insulating material and defining a surface generally extending along a plane of extension; and at least one electrode element arranged on the carrier element for at least one of emitting an electrical signal and receiving an electrical signal; wherein the at least one electrode element comprises a first wall section and a second wall section, wherein said first wall section, in a cross-section along a cross-sectional plane perpendicular to said plane of extension, extends straight along a perpendicular direction with respect to said plane of extension or at an oblique angle with respect to said perpendicular direction, the first wall section being in contact with the electrically insulating material of the carrier element, and wherein said second wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, adjoins said first wall section and is curved, the second wall section not being in contact with the electrically insulating material of the carrier element.

2. The medical electrode device according to claim 1, wherein the at least one electrode element comprises a third wall section adjoining the second wall section, wherein said third wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, extends straight in a direction parallel to said plane of extension.

3. The medical electrode device according to claim 1, wherein the at least one electrode element protrudes, along said perpendicular direction, from the carrier element beyond said surface.

4. The medical electrode device according to claim 1, wherein the second wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, comprises a curved portion having an angular width and a radius of curvature across said angular width.

5. The medical electrode device according to claim 4, wherein said radius of curvature is equal to or larger than 0.5 mm.

6. The medical electrode device according to claim 1, wherein the second wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, comprises a first curved portion and a second curved portion having a different curvature than the first curved portion, the second curved portion adjoining with said first wall section.

7. The medical electrode device according to claim 6, wherein the first curved portion comprises a first angular width and a first radius of curvature across said first angular width, and the second curved portion comprises a second angular width and a second radius of curvature across said second angular width.

8. The medical electrode device according to claim 7, wherein the first radius of curvature is larger than the second radius of curvature.

9. The medical electrode device according to claim 7, wherein the first radius of curvature is equal to or larger than 0.5 mm, and the second radius of curvature is equal to or larger than 0.1 mm.

10. The medical electrode device according to claim 1, wherein the carrier element comprises a body portion and an overlapping portion, wherein the body portion contacts said first wall section of the at least one electrode element and the overlapping portion overlaps with said second wall section of the at least one electrode element along said perpendicular direction without contacting the second wall section.

11. The medical electrode device according to claim 10, wherein the overlapping portion, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, extends at an angle with respect to the perpendicular direction.

12. The medical electrode device according to claim 1, wherein the at least one electrode element, in a cross-section parallel to said plane of extension, comprises a generally rectangular shape.

13. The medical electrode device according to claim 1, wherein the at least one electrode element is formed from a metal material in a deep-drawing process.

14. The medical electrode device according to claim 1, wherein the carrier element is made from a silicone material.

15. A method for fabricating a medical electrode device for implantation into a patient, the method comprising: forming a carrier element from an electrically insulating material such that the carrier element defines a surface generally extending along a plane of extension; forming, using a deep-drawing process, at least one electrode element for at least one of emitting an electrical stimulation signal and receiving an electrical sense signal; and arranging said at least one electrode element on said carrier element; wherein said forming the at least one electrode element includes: forming the at least one electrode element to comprise a first wall section and a second wall section adjoining said first wall section; wherein said arranging step includes: arranging said at least one electrode element on said carrier element such that the first wall section is in contact with the electrically insulating material of the carrier element and the second wall section is not in contact with the electrically insulating material of the carrier element, wherein said first wall section, in a cross-section along a cross-sectional plane perpendicular to said plane of extension, extends straight along a perpendicular direction with respect to said plane of extension or at an oblique angle with respect to said perpendicular direction, and wherein said second wall section, in said cross-section along said cross-sectional plane perpendicular to said plane of extension, is curved.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The various features and advantages of the present invention may be more readily understood with reference to the following detailed description and the embodiments shown in the drawings. Herein,

[0043] FIG. 1 shows a view of an electrode device connected to a stimulation device in an implanted state in the area of the spine of a patient;

[0044] FIG. 2 shows a view of the electrode device in the epidural space in the region of the spinal column;

[0045] FIG. 3 shows a view of a flattened end of an embodiment of an electrode device;

[0046] FIG. 4 shows a view of another embodiment of an electrode device;

[0047] FIG. 5 shows a cross-sectional view of an electrode element of the electrode device embedded in a carrier element of the electrode device;

[0048] FIG. 6 shows a view of an embodiment of an electrode element;

[0049] FIG. 7A shows a top view of the electrode element;

[0050] FIG. 7B shows a cross-sectional view along line A-A according to FIG. 7A;

[0051] FIG. 7C shows a cross-sectional view along line B-B according to FIG. 7A;

[0052] FIG. 8A shows a cross-sectional view of an embodiment of an electrode element;

[0053] FIG. 8B shows a cross-sectional view of another embodiment of an electrode element;

[0054] FIG. 9 shows a current density profile obtained for the different embodiments of the electrode elements according to FIGS. 8A and 8B;

[0055] FIGS. 10A-10F show different embodiments of electrode elements embedded in material of a carrier element of the electrode device;

[0056] FIG. 11 shows current densities as obtained for the different electrode elements according to FIGS. 10A to 10F; and

[0057] FIG. 12 shows a view of an electrode element according to another embodiment.

DETAILED DESCRIPTION

[0058] An electrode device 1, as shown in an embodiment in FIGS. 1 and 2, is formed as a so-called paddle electrode and comprises an electrode body 10 and an electrode end 11 connected to the electrode body 10, a plurality of electrode elements being attached to the electrode end 11 for injecting electrical current, e.g., in the region of the spinal column W of a patient P.

[0059] The electrode device 1 at a proximal end of the electrode body 10 is connected to a connector block 20 of a stimulation device 2, via which stimulation energy can be delivered to the electrode device 1 and radiated via the electrode arrangement arranged on the electrode end 11 to stimulate the spinal cord R in the region of the spinal column W.

[0060] As can be seen from the sectional view of FIG. 2, in the embodiment shown the electrode device 1 is implanted with the electrode end 11 in the epidural space E in the region of the spinal column W of the patient P in such a way that the electrode end 11 is located in the region of the spinal cord R and can thus introduce stimulation energy in a directed manner into the spinal cord R in order to effect nerve stimulation in the region of the spinal cord R.

[0061] While the electrode body 10, for example, comprises a circular (isodiametric) cross-section, the electrode device 1 is flattened in the area of the electrode end 11 which, as can be seen in FIG. 3, carries a plurality of electrode elements 12, which may be evenly or unevenly spaced on the electrode end 11 in such a way that stimulation energy can be fed in a directed manner, for example into the spinal cord R of a patient P.

[0062] As further illustrated in FIG. 3, each electrode element 12 is connected to a supply line 13, wherein each electrode element 12 can be connected to the stimulation device 2 via an associated, individual supply line 13 and thus may be supplied with stimulation energy via the stimulation device 2 to emit an electrical signal. The supply lines 13 are jointly routed as a cable strand in the electrode body 10 in an encapsulated manner to the stimulation device 2.

[0063] The electrode elements 12 are arranged on a carrier 14, but are exposed with a surface facing outwards and can therefore come into contact with surrounding tissue when the electrode device 1 is implanted in a patient.

[0064] FIG. 4 shows another embodiment of an electrode device 1 having an electrode end 11 comprising a flattened, paddle-like shape, the electrode end 11 being formed by a carrier element 14 across which an arrangement of electrode elements 12 is evenly distributed to effect an emission of electrical stimulation signals into or allow for a sensing of electrical sense signals from surrounding tissue. As visible from FIG. 4, the electrode elements 12 are exposed towards the outside, such that faces of the electrode elements 12 are not covered with material of the carrier element 14, the carrier element 14 forming a surface 142 from which the electrode elements 12 are exposed.

[0065] The surface 142 extends in a planar fashion along a plane of extension A spanned by horizontal directions X, Y, as indicated in FIG. 4. The carrier element 14 herein is formed from an electrically insulating material, in particular a silicone material.

[0066] Referring now to FIGS. 5 to 7A to 7C, in one embodiment one or multiple of the electrode elements 12, beneficially all of the electrode elements 12 of the electrode device 1 have a rounded, dome-like shape, as this is visible, for example, from the cross-sectional view of FIG. 5. The electrode element 12 is partially embedded within the material of the carrier element 14, such that the carrier element 12 is connected to the carrier element 14 by means of a material-fit connection.

[0067] As visible from FIGS. 6 and 7A to 7C, the electrode element 12 comprises a generally rectangular shape, forming opposite, short wall sections 120 and opposite, long wall sections 123. The wall sections 120 and the wall sections 123 are arranged at right angles with respect to each other to form the generally rectangular shape of the electrode element 12. Transitions between the wall sections 120, 123 herein are rounded, as visible from the top view of FIG. 7A.

[0068] As visible from the cross-sectional views of FIGS. 5 and 7B and 7C, the wall sections 120, 123—in the shown embodiment—extend along a perpendicular direction Z with respect to the surface 142 of the carrier element 14 and hence perpendicularly to the plane of extension A of the carrier element 14. The wall sections 120, 123, as visible from FIG. 5, are in contact with surrounding body portions 140 of the carrier element 14 and hence form a material-fit connection with the carrier element 14.

[0069] The wall sections 120, 123— in the cross-sectional planes of FIG. 5 and FIGS. 7B and 7C— each are adjoined by a curved wall section 121, 124, the curved wall sections 121, 124 forming rounded edges of the electrode element 12 converging into a flat, straight wall section 122 of the electrode element 12 facing towards the outside, as it is visible, for example, from FIG. 5. The curved wall sections 121, 124 hence form a rounded transition in between the perpendicular, straight wall sections 120, 123 and the flat, horizontal wall section 122 extending in parallel to the plane of extension A and facing towards the outside.

[0070] The curved wall sections 121, 124 in the shown embodiment are made up of different portions 121A, 121B, 124A, 124B when viewed along the cross-sectional planes as indicated by lines A-A and B-B in FIG. 7A, the different portions 121A, 121B, 124A, 124B being defined by different radii of curvature R1, R2 and extending across different angular widths β1, β2, as illustrated in FIGS. 7B and 7C.

[0071] In particular, a portion 121B, 124B having a radius of curvature R2, in the cross-sectional views of FIGS. 7B and 7C, adjoins the associated straight wall section 120, 123 and spans across an angular width 132. Another portion 121A, 124A adjoins the portion 121B, 124B and comprises a radius of curvature R1 being substantially larger than the radius of curvature R2, the portion 121A, 124A spanning across an angular width 131 and transitioning into the flat, horizontal wall section 122.

[0072] Due to the different radii of curvature R1, R2 each rounded wall section 121, 124 comprises a tighter curvature at the transition to the associated, perpendicular wall section 120, 123, and a substantially lesser curvature at the transition into the third, outer face 122.

[0073] The radius of curvature R2 may be equal to or larger than 0.1 mm, for example equal to or larger than 0.2 mm, for example 0.3 mm.

[0074] The radius of curvature R1 may be equal to or larger than 0.5 mm, in particular equal to or larger than 0.8 mm, for example 1 mm.

[0075] The electrode element 12 may, for example, have a length L1, as illustrated in FIG. 7A, in between 2 mm and 5 mm, for example 3.5 mm, and a width L2, for example in between 1 mm and 3 mm, for example 2 mm.

[0076] As visible from FIG. 5, the electrode element 12 protrudes from the carrier element 14 in that the flat, horizontal wall section 122 is placed at a height H3 beyond the surface 142 of the carrier element 14. The electrode element 12 may comprise an overall height H1 (measured along the vertical direction Z, without the contact elements 125). The straight, perpendicular wall sections may comprise a height H2, as illustrated in FIG. 5, approximately half the overall height H1.

[0077] As visible from FIG. 5, the body portion 140 of the carrier element 14 being in contact with the straight, perpendicular wall sections 120, 123 of the electrode element 12 is adjoined by an associated overlapping portion 141, the overlapping portion 141 overlapping with the curved wall sections 121, 124 in the perpendicular direction Z, as visible from FIG. 5. Herein, in the shown embodiment, the overlapping portion 141 is arranged at an angle α with respect to the perpendicular direction Z, the angle α lying, for example, in a range between 30° and 60°, for example at 45°.

[0078] By means of the angled overlapping portion 141, which does not contact the associated curved wall sections 121, 124, the electrode element 12 with its curved edges formed by the curved wall sections 121, 124 and the flat, outer wall section 122 is exposed towards the outside and may come into contact with surrounding tissue.

[0079] In addition, due to the shaping of the electrode element 12, in particular with the differently curved portions 121A, 121B, 124A, 124B of the curved wall sections 121, 124, an easy manufacturing process may be used, allowing, for example, a fabrication of the electrode element 12 using a deep-drawing process.

[0080] In a deep-drawing process, the electrode element 12 is formed from a sheet material using a stamping tool, the electrode element 12, as visible from FIG. 6, forming a recess 126 on its inside. Prior to forming the electrode element 12 by means of a deep-drawing process the electrode element 12 may be cut into shape, including, for example, contact elements 125 being formed at a lower edge of the electrode element 12, as visible from FIG. 6.

[0081] Because edges of the electrode element 12 are formed by curved wall sections 121, 124, a current density across the electrode element 12—when using the electrode device 1, for example, for a neuro-stimulation—may be improved in that the current density may be shaped to prevent density peaks at the edges of the electrode element 12.

[0082] This is illustrated in FIGS. 8A, 8B and FIG. 9. Herein, FIG. 9 shows current density profiles for the embodiments of the electrode element 12 as shown in FIG. 8A (version V1) and FIG. 8B (version V2).

[0083] Whereas the electrode device 12 of FIG. 8B corresponds to the embodiment of FIGS. 5 to 7A to 7C, in the embodiment of FIG. 8A the electrode device 12 comprises a smaller curvature in wall sections 121, 124 defined by a radius of curvature R3, the electrode element 12 in addition protruding by a reduced height H4 beyond the surface 142 of the carrier element 14.

[0084] As visible from FIG. 9, in the electrode element 12 according to FIG. 8B (version V2) a current density profile is obtained which exhibits a reduced peak height at edges of the electrode element 12, but an increased level in a center region of the electrode element 12, in comparison to the electrode element 12 according to the embodiment of FIG. 8A (version V1).

[0085] By reducing the level of peaks in the current density profile, a local heating and damaging of tissue during a stimulation operation may be prevented, and stimulation efficiency as well as reception sensitivity may be improved.

[0086] FIGS. 10A to 10F show—in cross-sectional views corresponding to the view of FIG. 5—different embodiments of electrode elements 12 as embedded in carrier elements 14, the electrode elements 12 differing in their rounded shape and in their placement within the carrier element 14.

[0087] In the embodiment of FIG. 10A (version V3), the electrode element 12 in its shape substantially matches the embodiment according to FIGS. 5 to 7A to 7C, but does not protrude beyond the surface 142 of the carrier element 14. The carrier element 14 herein forms an overlapping portion 141, which however is not arranged at an angle with respect to the perpendicular direction Z.

[0088] In the embodiment of FIG. 10B (version V4), the electrode element 12 is substantially shaped as in the embodiment of FIG. 8A, but does not protrude beyond the surface 142 of the carrier element 14. The electrode element 12 is embedded into the carrier element 14 such that the planar, horizontal face 122 of the electrode element 12 comes to lie beneath the surface 142. The carrier element 14, like in the embodiment of FIG. 10A, forms an overlapping portion 141 which is not arranged at an angle with respect to the perpendicular direction Z.

[0089] The embodiment of FIG. 10C (version V5) matches the embodiment of FIG. 10B, wherein however the horizontal wall section 122 is arranged at substantially the same height as the surface 142.

[0090] The embodiment of FIG. 10D (version V6) substantially matches the embodiment of FIG. 10C, wherein however the horizontal wall section 122 protrudes beyond the surface 142.

[0091] The embodiment of FIG. 10E (version V7) substantially matches the embodiment of FIG. 10C, wherein the carrier element 14 forms an overlapping portion 141 arranged at an angle with respect to the perpendicular direction Z.

[0092] The embodiment of FIG. 10F (version V8) substantially matches the embodiment of FIG. 10A, wherein, like in FIG. 10E, the carrier element 14 forms an overlapping portion 141 arranged at an angle with respect to the perpendicular direction Z.

[0093] FIG. 11 shows current density profiles for the different embodiments of FIGS. 10A to 10F, as measured across the electrode surface along the cross-sectional planes of FIGS. 10A to 10F. For the different embodiments herein different shapes of the current density profiles are obtained, the current density profiles generally differing in peak heights obtained at the edges of the respective electrode element 12 and a level in a central region of the electrode element 12.

[0094] From FIG. 11 it generally can be concluded that a widened curvature at the edges, as in the embodiments of FIGS. 10A and 10F, may yield an improved current density profile, exhibiting reduced current density peaks at the edges and a rather flattened, even density across the electrode element 12.

[0095] FIG. 12 shows another embodiment of an electrode element 12, which substantially matches the embodiment of the electrode element described above according to FIGS. 6 and 7A to 7C. In comparison to the embodiment of FIGS. 6 and 7A to 7C, however, at least one of the straight wall sections 120, 123 pointing inwards is arranged at an oblique angle with respect to the perpendicular direction Z, such that inner edges of the electrode element 12 are outwardly flared, as visible from FIG. 12. Hence, in this embodiment one or both of the straight wall sections 120, 123, which are in contact with the material of the carrier element 14, are not arranged along the perpendicular direction Z, but are arranged at an oblique angle, allowing, for example, to smooth a transition in between the sections 120, 123 and the adjoining sections 121, 124.

[0096] The idea underlying the present invention is not limited to the embodiments described above, but may be implemented in a different fashion.

[0097] An electrode device as described herein may generally be used as neuro-stimulation electrode in combination with a neuro-stimulation device in the region of the spinal column or for brain stimulation. An electrode device of the type described herein however may also be used in other applications within a patient, for example for emitting stimulation signals or receiving sense signals, for example in cardiac applications.

[0098] The electrode device may comprise one or multiple electrodes elements, wherein the electrode elements may be evenly or unevenly distributed across a carrier element.

[0099] Although the carrier element has been described herein as having a generally flat shape, the carrier element may likewise have a curved shape and may extend along a curved plane of extension.

[0100] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.

LIST OF REFERENCE NUMERALS

[0101] 1 Implantable electrode device [0102] 10 Electrode body [0103] 11 Electrode end [0104] 12 Electrode element [0105] 120-124 Wall section [0106] 121A, 121B Curved portion [0107] 124A, 124B Curved portion [0108] 125 Protrusion element [0109] 126 Recess [0110] 13 Supply line [0111] 14 Carrier element [0112] 140 Body portion [0113] 141 Overlapping portion [0114] 142 Surface [0115] 2 Stimulation device [0116] 20 Connector block [0117] α Angle [0118] β1, β2 Angular width [0119] A Plane of extension [0120] E Epidural space [0121] H1-H3 Height [0122] L1 Length [0123] L2 Width [0124] P Patient [0125] R Spinal cord [0126] R1-R3 Radius [0127] V1-V8 Version [0128] W Spinal column [0129] X, Y, Z Spatial direction