How effective are disc replacement options in lumbar spine? cervical spine?

See below: They are safe and effective and have similar results as the clasSic ACDF their advantages over the fusion are theoretical in my opinion the Acdf has a 95% chance at relieving arm pain neither are neck pain procedures , both do a good job relieving arm pain from pinched neck nerves early adopters of new technology can be surprised by outcomes since they are not as well studied without long term