Abstract: An electrode is provided for partial insertion into a nucleus pulposus of an intervertebral disc. The electrode includes a tubular insulator, which defines a channel therethrough; and a coiled wire partially disposed in the channel of the tubular insulator so that an intra-annular longitudinal segment of the coiled wire is disposed within the channel of the tubular insulator, and a distal non-electrically-insulated longitudinal segment of the coiled wire extends distally out of a distal end of the tubular insulator. The electrode is partially insertable into the nucleus pulposus so that the distal non-electrically-insulated longitudinal segment of the coiled wire is positioned within the nucleus pulposus, the intra-annular longitudinal segment of the coiled wire is positioned within an annulus fibrosus of the intervertebral disc, and the tubular insulator is positioned at least partially within the annulus fibrosus. Other embodiments are also described.

Abstract: A method is provided that includes providing an electrode, which includes a wire that has a wire diameter of between 75 and 125 microns. The wire includes a non-electrically-insulated current-application longitudinal segment, which, in the absence of any applied forces, is coiled and has (i) an outer coil diameter of between 3 and 7 times the wire diameter, and (ii) an entire longitudinal length of between 5 and 35 mm. The wire further includes an electrically-insulated lead longitudinal segment, which has an entire longitudinal length of at least 10 mm, in the absence of any applied forces. At least a portion of the electrode is implanted in a body of a subject. Other embodiments are also described.

Abstract: Apparatus for driving fluid between first and second anatomical sites of a subject is provided, comprising (1) a first electrode, configured to be coupled to the first anatomical site of the subject; (2) a second electrode, configured to be coupled to the second anatomical site of the subject; and (3) a control unit, configured to (i) detect a pressure difference between the first and second anatomical sites, and (ii) in response to the detected pressure difference, drive fluid between the first and second anatomical sites by applying a treatment voltage between the first and second electrodes. Other embodiments are also described.

Abstract: Apparatus is provided that includes a first electrode, configured to be implanted at a first anatomical site in a nucleus pulposus of an intervertebral disc of a subject, and a second electrode, configured to be implanted at a second anatomical site outside the nucleus pulposus of the disc. A control unit is configured to detect a pressure difference between the first and the second anatomical sites by detecting a streaming voltage between the first and the second electrodes, and, in response to the detected pressure difference, drive fluid between the nucleus pulposus and outside the nucleus pulposus by applying a treatment voltage between the first and the second electrodes. Other embodiments are also described.

Abstract: Apparatus for treating an intervertebral disc of a subject is provided. The apparatus includes at least three intra-pulposus exposed electrode surfaces, which are configured to be implanted within a nucleus pulposus of the disc, at different respective locations; and one or more extra-pulposus exposed electrode surfaces, which are configured to be implanted outside the nucleus pulposus, in electrical communication with the disc. Control circuitry is configured to (a) configure the intra-pulposus exposed electrode surfaces to be cathodes, and the one or more extra-pulposus exposed electrode surfaces to be one or more anodes, and (b) drive the intra-pulposus exposed electrode surfaces and the one or more extra-pulposus exposed electrode surfaces to electroosmotically drive fluid into the nucleus pulposus to increase pressure in the disc.

Abstract: A method is provided for treating an intervertebral disc of a subject, the method including implanting at least one intra-pulposus exposed electrode surface in a nucleus pulposus of the intervertebral disc, and implanting one or more extra-pulposus exposed electrode surfaces outside the nucleus pulposus, in electrical communication with the intervertebral disc. Control circuitry, while electrically coupled to the at least one intra-pulposus exposed electrode surface and the one or more extra-pulposus exposed electrode surfaces, is activated to drive fluid and introduce nutritional substances into the intervertebral disc, by applying a voltage between the at least one intra-pulposus exposed electrode surface and the one or more extra-pulposus exposed electrode surfaces. Other embodiments are also described.

Abstract: A method for treating an intervertebral disc of a subject is provided, the method including delivering a growth factor to a nucleus pulposus of the intervertebral disc. At least one intra-pulposus exposed electrode surface is implanted in the nucleus pulposus. At least one extra-pulposus exposed electrode surface is implanted in a body of the subject outside the nucleus pulposus. The growth factor is supported by activating control circuitry to drive the intra-pulposus and the extra-pulposus exposed electrode surfaces to electroosmotically drive nutrient-containing fluid into the nucleus pulposus. Other embodiments are also described.

Abstract: Apparatus (20) for treating an intervertebral disc (30) of a subject is provided. The apparatus (20) includes at least three intra-pulposus exposed electrode surfaces (40), which are configured to be implanted within a nucleus pulposus (42) of the disc (30), at different respective locations; and one or more extra-pulposus exposed electrode surfaces (44), which are configured to be implanted outside the nucleus pulposus (42), in electrical communication with the disc (30). Control circuitry (50) is configured to (a) configure the intra-pulposus exposed electrode surfaces (40) to be cathodes, and the one or more extra-pulposus exposed electrode surfaces (44) to be one or more anodes, and (b) drive the intra-pulposus exposed electrode surfaces (40) and the one or more extra-pulposus exposed electrode surfaces (44) to electroosmotically drive fluid into the nucleus pulposus (40) to increase pressure in the disc (30).

Abstract: A method is provided for treating an intervertebral disc of a subject, the method including delivering cells to a nucleus pulposus of the intervertebral disc. At least one intra-pulposus exposed electrode surface is implanted in the nucleus pulposus. At least one extra-pulposus exposed electrode surface is implanted in a body of the subject outside the nucleus pulposus. The delivered cells are supported by activating control circuitry to drive the intra-pulposus and the extra-pulposus exposed electrode surfaces to electroosmotically drive nutrient-containing fluid into the nucleus pulposus. Other embodiments are also described.