A spinal implant (40) including first spinal attachment member (44) for attaching to a first spinal portion (41), second spinal attachment member (46) for attaching to a second spinal portion (42), and a post-implantation variable dimension device disposed between the first and second spinal attachment members, which is operable after completing surgery in which said spinal implant was installed into a patient, to cause relative movement between the first and second spinal attachment members.