| abstract |
The present invention provides a prosthetic cover (12) shaped to form a replacement nucleus pulposis (56) for an intervertebral disc (50), said cover comprising a permeable layer of an immunologically neutral material terminating in a valve structure (16) to allow the introduction of a hydrogel material (14); characterized in that a transudative material is disposed on the intended inner face of the cover to allow a through flow of low molecular weight materials only. |