Two devices, Hydraflex® and the NeuDisk®, are based on a hydrogel composition Hydrogel has biomechanical properties similar to the nucleus. Since its inception, several design changes and modifications of the hydrogel composition have been made to improve the biomechanical properties of the Hydraflex.

Other Nucleus Arthroplasty technologies are also under development by companies like Raymedica PDN, Newcleus, Howmedica Osteonic, Disc Dynamics, Cryolife, Disc Augmentation Technologies, and Replication Medical. The technologies include new devices and injectable compounds, which harden after injection. These technologies have yet to be fully tested and it remains to be seen, if they will be safe and effective over time.