Various implants and surgical techniques for dynamic spinal tethering systems are discussed. In an example, a spinal tethering system can comprise a flexible elongate spinal tethering cord and a plurality of vertebral implants connecting the cord across at least four spinal levels. In this example, each vertebral implant of the plurality of vertebral implants can include a dynamic head coupling each vertebral implant to the cord. The dynamic head of each vertebral implant can be configured to share cord tension across multiple spinal levels by releasing a first tension generated at a first level between two vertebral implants of the plurality of vertebral implants to generate a second tension across two spinal levels between three vertebral implants of the plurality of vertebral implants, wherein the second tension is lower than the first tension.