Lumbar curve is stable after selective thoracic fusion for adolescent idiopathic scoliosis: A 20-year follow-up

STUDY DESIGN.: A retrospective cohort study comparing long-term clinical and radiographical outcomes using selective thoracic instrumented fusion versus long instrumented fusion for the treatment of adolescent idiopathic scoliosis (AIS). OBJECTIVE.: To evaluate long-term behavior of the lumbar curve in patients with AIS treated with selective thoracic fusion and to assess clinical outcome measures in this patient population compared with those patients treated with fusion in the lumbar spine. SUMMARY OF BACKGROUND DATA.: Selective thoracic fusion for the treatment of AIS preserves motion segments, but leaves residual lumbar deformity. Long-term results of selective fusion using segmental fixation are limited. METHODS.: Nineteen patients with AIS treated with selective thoracic fusion and 9 patients treated with a long fusion returned at a mean 20 years (range, 14-24 years) postoperatively for radiographs, clinical evaluation, and outcome surveys (Short Form-12, Scoliosis Research Society-24, Spinal Appearance Questionnaire, Oswestry Disability Index, and visual analogue scale for pain and stiffness). Curve types were Lenke 1B, 1C, or 3C. All patients underwent posterior fusion with Texas Scottish Rite Hospital or Cotrel-Dubousset hook-rod instrumentation. RESULTS.: The selective thoracic fusion group had no significant progression in the lumbar curve magnitude and no worsening of L4 obliquity to the pelvis between initial postoperative and 20-year follow-up. Mean preoperative lumbar curve magnitude (mean, 44°; range, 32-64) corrected 43% on initial postoperative films versus 38% at latest follow-up. Mean L4 obliquity to the pelvis, trunk shift, sagittal balance, and coronal balance were stable over time. Outcome scores between the 2 groups were similar. Scores in long fusion group, when compared with the selective group, were higher for 2 Scoliosis Research Society domains: self-image after surgery (P = 0.005) and function after surgery (P = 0.0006). CONCLUSION.: Spinal balance and correction of the lumbar curve remain stable over time in selective thoracic fusion. Those with selective fusions have outcome measures comparable with those with long fusions.