PMCF (Post-Market Clinical Follow-up) Study on The Tether™ in UK (United Kingdom)

Inclusion Criteria: * Diagnosis of progressive idiopathic scoliosis; * Skeletally immature, based on both Risser (\<5) and Sanders (\<8) assessments; * Major Cobb angle ≥30° and ≤65°; * Osseous structure dimensionally adequate to accommodate screw fixation, as determined by radiographic imaging; * Failed bracing and/or be intolerant to brace wear; * Lenke Type 1 curves (i.e., main thoracic); * Signed Informed Consent Form by legal guardian or by the patient if ≥ 16 years old. * The decision to treat patients with The Tether™ - VBT System was made by the patient's clinician outside of this research Exclusion Criteria: * Presence of any systemic infection, local infection, or skin compromise at the surgical site; * Prior spinal surgery at the level(s) to be treated; * Known poor bone quality defined as a T-score -1.5 or less; * Skeletal maturity; * Any other medical or surgical condition which would preclude the potential benefit of spinal surgery, such as coagulation disorders, allergies to the implant materials, and patients unwillingness or inability to cooperate with post-operative care instructions; * Unwillingness, inability, or living situation (e.g., custody arrangements, homelessness, detention) that would preclude ability to return to the study site for follow-up visits as described in protocol and Informed Consent; * Patients who are pregnant at the time of enrollment.