A head holder for holding and tensioning the head of a bone screw, particularly a pedicle screw, is provided. Also provided is a ratcheting connector for connecting to the head holders while permitting rotational movement of the head holder when engaged with the ratcheting connector. Also provided is a flex arm connector for connecting multiple ratcheting connectors across multiple vertebral bodies. A tool set for managing and/or correcting spinal deformities, such as scoliosis, including at least one or more head holders and one or more ratcheting connectors is provided.