Disc therapy

Apparatus for treating an intervertebral disc of a subject, the apparatus comprising:

• 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;
• one or more extra-pulposus exposed electrode surfaces, which are configured to be implanted outside the nucleus pulposus, in electrical communication with the disc;
• and
• control circuitry, which is configured to:
• 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
• 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 based on a circadian cycle of the subject.

Apparatus for treating an intervertebral disc of a subject, the apparatus comprising:

• 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;
• one or more extra-pulposus exposed electrode surfaces, which are configured to be implanted outside the nucleus pulposus, in electrical communication with the disc;
• and
• control circuitry, which is configured to:
• 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
• 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 by applying:
• (a) a first voltage between at least a first one of the intra-pulposus exposed electrode surfaces and at least one of the one or more extra-pulposus exposed electrode surfaces, and
• (b) a second voltage between at least a second one of the intra-pulposus exposed electrode surfaces and at least one of the one or more extra-pulposus exposed electrode surfaces, the second voltage different from the first voltage.