No Significant Radiological Signs of Adult Spinal Deformity Progression after a Mean of 11 Years of Follow-Up Following Harrington Rod Instrumentation Removal and Watchful Waiting

The study aimed to assess long-term radiological outcomes in patients from our institution who were primarily treated for adolescent idiopathic scoliosis with surgical correction using Harrington rod (HR) instrumentation, and afterward with watchful waiting of residual spinal deformity after HR removal, whereby no patient consented to spinal deformity correction. A single-institution case series of 12 patients was retrospectively evaluated. Preoperative and most recent post-instrumentation removal radiographic measurements were compared, along with baseline characteristics. The average age of patients (all females) at the time of HR instrumentation removal was 38 ± 10 years (median 40, range 19-54). The mean follow-up from the HR instrumentation implantation to the HR instrumentation removal was 21 ± 10 years (median 25, range 2-37), with a further mean of 11 ± 10 years (median 7, range 2-36) of follow-up following HR instrumentation removal and watchful waiting. No significant change in radiological parameters was observed: LL ( = 0.504), TK ( = 0.164), PT ( = 0.165), SS ( = 0.129), PI ( = 0.174), PI-LL ( = 0.291), SVA ( = 0.233), C7-CSVL ( = 0.387), SSA ( = 0.894), TPA ( = 0.121), and coronal Cobb angle (proximal ( = 0.538), main thoracic ( = 0.136), and lumbar ( = 0.413)). No significant change in coronal or sagittal parameters was observed in this single-institution long-term radiological outcome study of adults following HR instrumentation removal and watchful waiting of residual spinal deformity.