Patent Description:
In such a method, an electrically insulating support and at least one electrically conductive electrode element are provided in order to attach the at least one electrically conductive electrode element to the support.

By means of such an electrode device, a stimulation signal may be emitted when implanted in a patient, for example to cause spinal nerve stimulation. For this purpose, the electrode device may be introduced into the epidural space near the spinal cord of the spine, for example, in order to achieve nerve stimulation of the spinal cord by introducing electrical stimulation energy. However, such an electrode device may also be used for cardiac stimulation, for example together with a pacemaker system or a defibrillation system.

Electrode devices used, for example, for spinal nerve stimulation may be in the form of isodiametric electrodes formed with an approximately circular cross-section, a diameter usually less than <NUM> and ring electrodes arranged thereon, or in the form of so-called paddle electrodes with a flattened end formed on an electrode body, on which a plurality of electrode elements are usually arranged. While isodiametric electrodes may be easily implanted percutaneously and require a small implantation space, paddle electrodes may have improved efficiency due to the fact that an electrode array formed on the flattened end may have a directional characteristic that allows targeted delivery of stimulation energy.

A challenge with such paddle electrodes, however, is to attach the electrode arrangement to the flattened end of the paddle electrode in a simple, reproducible and exactly placeable manner, if possible in a way that may be easily automated.

Designs of paddle electrodes are known, for example, from <CIT> and <CIT>.

The object of the present invention is to provide a method for producing an implantable electrode device and an implantable electrode device, which enable a simple and automatable manufacture with the possibility for exact placement of one or more electrode elements.

This object is achieved by subject matter comprising the features of claim <NUM>.

Accordingly, to attach the at least one electrode element to the support, the at least one electrode element and/or the support are heated and the at least one electrode element is pressed against the support.

Attaching the at least one electrode element to the support is done by heating the electrode element and/or the support. The support is made, for example, of a thermoplastic, for example a material comprising polyurethane, so that the support becomes soft when heated and the at least one electrode element may thus be pressed at least partially into the support, thereby forming an integrally bonded connection to the support. The attachment of the at least one electrode element may thus be carried out in a method step that may be easily automated, without the need to additionally produce, for example, an adhesive bond or the like by means of an adhesive for fixing the at least one electrode element to the support.

The material of the support may be heated by heating the at least one electrode element before attaching it to the support. When the at least one electrode element is attached to the support, heat is transferred from the electrode element to the support and heats the support so that the support, which is preferably made of a thermoplastic, becomes soft and thus enters into an integral bond with the at least one electrode element.

In addition or alternatively, the support may also be heated so that the support is heated by a heat source in addition or alternatively to a heat transfer from the electrode element to the support in order to attach the at least one electrode element to the support.

For the attachment of the at least one electrode element, in one embodiment the at least one electrode element and/or the support are heated to a temperature which is at or near the melting temperature of the support material, for example a temperature greater than <NUM>, preferably greater than <NUM>, more preferably greater than <NUM>, for example <NUM>. The heating may be carried out, for example, in a furnace in which the at least one electrode element and/or the support to be heated are placed. Alternatively, a locally acting heat source may be used to heat the at least one electrode element or the support. The at least one electrode element may then be placed on the support for example in an automated manner, for example using a robot, with the placement being carried out by pressing the at least one electrode element against the support and thus without any further method step for fastening the at least one electrode element to the support.

The support may be made of a thermoplastic material, for example a polyurethane material, by means of a film with a thickness between <NUM> and <NUM>, for example <NUM>. For example, the support may have a surface area of between <NUM> by <NUM> and <NUM> by <NUM>.

Each electrode element, for example, may have a thickness between <NUM> and <NUM> and is made of a metal material, for example a platinum material. For example, the electrode element may have a surface area of between <NUM> by <NUM> and <NUM> by <NUM>, for example <NUM> by <NUM>.

In one embodiment, the at least one electrode element is placed with an underside against an upper side of the support. The at least one electrode element may be pressed against the support in such a way that an upper side of the at least one electrode element is flush with the upper side of the support. In another embodiment, however, the at least one electrode element may also be attached to the support in such a way that the at least one electrode element protrudes from the support and thus protrudes with respect to the upper side of the support. The indentation depth to which the at least one electrode element is pressed into the support may be selected in principle, for example, depending on a desired radiation characteristic for the delivery of stimulation energy via the electrode element.

In one embodiment, an electrical supply line is connected to the at least one electrode element before the at least one electrode element is attached to the support. In this embodiment of the method, the supply line connected to the at least one electrode element is preferably placed on the support together with the at least one electrode element and is pressed into the support as the at least one electrode element and/or the support are heated, so that the supply line connected to the at least one electrode element is embedded in the support at least in a region below the electrode element.

In one embodiment, the supply line connected to the at least one electrode element is embedded in the support along the course of said line in the region of the support.

In one embodiment, the electrical supply line is designed as a wire or cord.

In one embodiment, the at least one electrode element has at least one fastening element which is pressed into the support when the at least one electrode element is attached. The at least one fastening element may, for example, protrude in the manner of a tab from an underside of the electrode element facing the support and, when the at least one electrode element is placed, comes into engagement with the support so that an additional form-fitting connection between the at least one electrode element and the support is created via the at least one fastening element and the hold of the at least one electrode element on the support is improved.

The at least one fastening element may, for example, have a hook shape, for example in the form of a barb, wherein, additionally or alternatively, for example, an opening may be formed in the at least one fastening element, with which the material of the support may engage when the at least one electrode element is placed, so that a firm hold of the at least one electrode element on the support is created.

In one embodiment, the at least one electrode element has a pin which protrudes from an underside of the electrode element facing the support and is pressed into the support when the at least one electrode element is placed. When the at least one electrode element is placed, the pin penetrates the support in such a way that the pin is accessible on an underside facing away from the upper side of the support, which makes it possible to connect an electrical supply line via the pin to the at least one electrode element after the at least one electrode element has been placed. The connection of the supply line may be made here in the region of the underside of the support, so that the supply line is located on the underside of the support and thus not on the side of the electrode device through which stimulation energy is emitted during operation.

In one embodiment, the support is at least partially surrounded by an encasement after the attachment of the at least one electrode element, for example by overmoulding the support in some sections with the material of the encasement. The encasement may, for example, be made of a silicone material, and, for example, the support may be completely encased, except for the surfaces of the electrode elements attached to the support which are to be exposed outwardly in order to release stimulation energy during operation of the electrode device.

In one embodiment, a plurality of electrode elements are attached to the support. The electrode elements may be attached to the support to form a regular arrangement, for example in the manner of a matrix, with, for example, a number of rows of electrode elements possibly being formed on the support. For example, two rows of electrode elements may be attached to the support, in which rows there are arranged electrode elements next to each other.

An implantable electrode device has an electrode body connectable to a generator and an electrode end connected distally to the electrode body. The electrode end comprises a support and a plurality of electrode elements attached to the support, the electrode elements being attached to the support by the method described above.

The advantages and advantageous embodiments described above for the method may be applied analogously to the electrode device, and therefore reference should be made in full to the above.

Such an electrode device realises in particular a paddle electrode which may be implanted, for example, for spinal nerve stimulation in an epidural space in the region of the spine and thus adjacently to the spinal cord, in order to effect nerve stimulation in a targeted manner in the region of the spinal cord.

The concept underlying the invention is explained in more detail below with reference to the embodiments shown in the figures, in which:.

An electrode device <NUM> shown in <FIG> and <FIG> in one embodiment is realised as a so-called paddle electrode and has an electrode body <NUM> and an electrode end <NUM> connected to the electrode body <NUM>, to which electrode end there are attached a plurality of electrode elements for emitting stimulation energy in the region of the spine W of a patient P.

The electrode device <NUM> is connected by a proximal end of the electrode body <NUM> to a terminal block <NUM> of a generator <NUM>, via which stimulation energy may be delivered to the electrode device <NUM> and radiated via the electrode arrangement arranged at the electrode end <NUM> for stimulation of the spinal cord R in the region of the spine W.

As may be seen from the sectional view according to <FIG>, in the embodiment shown, the electrode device <NUM> is implanted with the electrode end <NUM> in the epidural space E in the region of the spine W of the patient P in such a way that the electrode end <NUM> is located in the region of the spinal cord R and may thus introduce stimulation energy in a directed manner into the spinal cord R in order to cause nerve stimulation in the region of the spinal cord R.

While the electrode body <NUM>, for example, has a circular (isodiametric) cross-section, the electrode device <NUM> is flattened in the region of the electrode end <NUM> and, as may be seen in <FIG>, carries a plurality of electrode elements <NUM> there, which may be arranged in two rows next to each other and are placed in relation to each other in such a way that stimulation energy may be fed in a directed manner, for example into the spinal cord R of a patient P.

As further shown in <FIG>, each electrode element <NUM> is connected to a supply line <NUM>, and each electrode element <NUM> may be connected to the generator <NUM> via an associated supply line <NUM> and may thus be supplied with stimulation energy via the generator <NUM> to emit an electrical signal. The supply lines <NUM> are routed together as a cable harness in the electrode body <NUM> in an encapsulated manner to the generator <NUM>.

The electrode elements <NUM> are arranged on a support <NUM>, but are exposed with a surface facing outwardly and may therefore come into contact with surrounding tissue when the electrode device <NUM> is implanted in a patient.

For the fastening of the electrode elements <NUM> to the support <NUM>, there is a desire for an automatable, simple production process that allows the exact placement of the electrode elements <NUM> on the support <NUM>.

To this end, it is proposed here to attach the electrode elements <NUM> to the support <NUM> by heating the support <NUM> and/or the corresponding electrode element <NUM> so that the electrode element <NUM> in question may be pressed into the support <NUM> and may form an integrally bonded connection to the support <NUM>.

This is illustrated in <FIG>. For example, an electrode element <NUM> to be connected to the support <NUM> may be heated to a temperature at or near the melting temperature of the material of the support <NUM>, which is made for example of a thermoplastic material, for example a polyurethane material, so that when the electrode element <NUM> is placed, the support <NUM> is melted in some regions and the electrode element <NUM> may thus be pressed into the support <NUM>, so that an integral bond is created between the electrode element <NUM> and the support <NUM>.

In the embodiment shown in <FIG>, the electrode element <NUM> is placed in a joining direction F against an upper side <NUM> of the support element <NUM> in such a way that - as may be seen in <FIG> - an upper side <NUM> of the electrode element <NUM> is flush with the upper side <NUM>. The indentation depth T to which the electrode element <NUM> is pressed into the support <NUM>, thus corresponds to the thickness of the electrode element <NUM>.

It should be noted that the upper side <NUM> of the electrode element <NUM> does not necessarily have to be flush with the upper side <NUM> of the support <NUM>. The electrode element <NUM> may also be placed on the support <NUM> in such a way that the upper side <NUM> of the electrode element <NUM> for example protrudes relative to the upper side <NUM> of the support <NUM>. In general, the electrode element <NUM> may be placed on the support <NUM> with regard to the indentation depth T in such a way that a radiation characteristic for radiating electrical signals via the electrode element <NUM> is optimised.

To attach the electrode element to the support <NUM>, the electrode element <NUM> may be heated and brought to a temperature at or near the melting temperature of the material of the support <NUM>, for example. Additionally or alternatively, the support <NUM> may also be heated. For example, to attach the electrode element <NUM> to the support <NUM>, the electrode element <NUM> and/or the support <NUM> may be heated to a temperature higher than <NUM>, for example higher than <NUM>, preferably higher than <NUM>, for example <NUM>.

In the embodiment shown in <FIG>, a supply line <NUM> is connected to the electrode element <NUM> before the electrode element <NUM> is attached to the support <NUM>. In the example shown here, the supply line <NUM> is connected to an underside <NUM> of the electrode element <NUM> facing away from the upper side <NUM>, so that when the electrode element <NUM> is placed on the support <NUM>, the supply line <NUM> is located in some sections below the electrode element <NUM> and is pressed into the material of the support <NUM> together with the electrode element <NUM>. The supply line <NUM> is thus embedded below the electrode element <NUM> in the support <NUM>, so that the point of connection of the supply line <NUM> to the electrode element <NUM> is encased by the support <NUM> and the electrical connection between the supply line <NUM> and the electrode element <NUM> is thus secured.

In the embodiment shown in <FIG>, the electrode element <NUM> forms a flat, for example rectangular or round surface element, which, with the upper side <NUM> in the attached position, points outwards and may emit electrical signals via the upper side <NUM> for stimulation, for example in the region of the spinal cord R of a patient P.

As shown in an embodiment in <FIG>, the electrode element <NUM> may have fastening elements <NUM> in the form of tabs protruding from the underside <NUM>, which serve to improve the mechanical connection of the electrode element <NUM> to the support <NUM>. When the electrode element <NUM> is attached to the support <NUM>, the fastening elements <NUM> come into form-fitting engagement with the support <NUM> and thus create a form fit between the electrode element <NUM> and the support <NUM>, so that above this the hold of the electrode element <NUM> on the support <NUM> is improved.

A plurality of fastening elements <NUM> can, for example, be formed along the outer peripheral edge of the electrode element <NUM> at a distance from each other on the electrode element <NUM>.

The fastening elements <NUM> can, for example, have a hook shape, for example in the form of barbs. In addition or alternatively, openings may be formed on the fastening elements <NUM>, in which openings the material of the support <NUM> may engage when the attachment is made, so that a form-fit hold of the electrode element <NUM> on the support <NUM> is further improved.

In another embodiment, shown in <FIG>, a pin <NUM> is formed on the underside <NUM> of the electrode element <NUM>, which pin penetrates the support <NUM> when the electrode element <NUM> is placed and thus becomes accessible on an underside <NUM> of the support <NUM> facing away from the upper side <NUM>, so that a supply line <NUM> may be connected to the pin <NUM>.

In a more detailed embodiment, shown in <FIG>, a head <NUM> may be formed on the pin <NUM>, which head forms an undercut, so that, via the pin <NUM>, the mechanical hold of the electrode element <NUM> on the support <NUM> is also improved since a form fit with the support <NUM> is formed via the head <NUM>, as shown in <FIG>. A supply line <NUM> may also be connected to the head <NUM>, as shown in <FIG>.

Via the pin <NUM> - in the embodiments of the electrode element <NUM> according to <FIG> - a supply line <NUM> may be connected after attaching the electrode element <NUM> to the support <NUM>. In this case, the supply line <NUM> may be laid in the region of the underside <NUM> and thus on a rear side of the support <NUM>, which faces away from the side of the electrode device <NUM> through which energy is radiated during operation. This may simplify the laying of the supply lines <NUM> to the different electrode elements <NUM>.

After attaching (all) the electrode elements <NUM> to the support <NUM>, the support <NUM> may be surrounded for example by an encasement <NUM>, for example by overmoulding the support <NUM>, as shown in <FIG>. The encasement <NUM> may, for example, be made of a silicone material, and the support <NUM> may be completely surrounded by the material of the encasement <NUM>, but the electrode elements <NUM> attached to the support <NUM> are exposed outwardly. By means of the encasement, the electrode device <NUM> may thus be enclosed and encapsulated in the region of the electrode end <NUM>.

The concept underlying the invention is not limited to the embodiments described above, but may also be realised in other ways, as long as they fall within the scope of the appended claims.

The electrode device may be used for spinal nerve stimulation, but also for other stimulation, for example cardiac stimulation.

Claim 1:
A method for producing an implantable electrode device (<NUM>) comprising an electrode body (<NUM>) connectable to a generator (<NUM>) and an electrode end (<NUM>) distally connected to the electrode body (<NUM>), the electrode end (<NUM>) comprising an electrically insulating support (<NUM>) and at least one electrode element (<NUM>) attached to the support (<NUM>), wherein the support (<NUM>) comprises at least one flat surface, the method comprising the steps of: providing an electrically insulating support (<NUM>), providing the at least one electrically conductive electrode element (<NUM>), and attaching the at least one electrode element (<NUM>) to the at least one flat surface of the support (<NUM>), wherein for attaching the at least one electrode element (<NUM>) to the support (<NUM>), the at least one electrode element (<NUM>) and/or the support (<NUM>) are heated and the at least one electrode element (<NUM>) is pressed against the support (<NUM>).