Outcomes following instrumentation removal after posterior corrective fixation in adolescent idiopathic scoliosis

Purpose To evaluate the complications and postoperative outcomes of implant removal after posterior fixation in adolescent idiopathic scoliosis. Methods We retrospectively reviewed the data of patients who underwent implant removal after posterior corrective fixation for adolescent idiopathic scoliosis between 2002 and 2014. Complications were evaluated in the 116 patients who underwent implant removal at their choice. Radiological evaluations were performed and analyzed in 71 patients who were followed up for > 2 years after implant removal. Moreover, the patients were divided into two groups: those with increased thoracic kyphosis after implant removal and those without. Results Overall, 14 of the 116 patients had complications. Two of the three patients with fractures required reoperation. Radiological examination revealed no significant difference in the scoliosis curvature in the coronal plane after implant removal. In the sagittal plane, the lowest instrumented vertebral tilt, cervical lordosis, T1 slope, T1-12 kyphosis angle, and T5-12 kyphosis angle were significantly increased. Moreover, patients with an increased T5-12 kyphosis angle after implant removal had greater pelvic incidence (PI) and sacral slope (SS) before implant removal. Conclusion The prevalence of complications after implant removal in adolescent idiopathic scoliosis was 12.1%. Spinal alignment is more variable in the sagittal plane than in the coronal plane, and patients with increased thoracic kyphosis after implant removal have greater preoperative PI and SS. Sufficient preoperative explanation is necessary if a patient wishes to undergo implant removal.