Severe (>100 Degrees) Thoracic Adolescent Idiopathic Scoliosis - A Comparison of Surgical Approaches

Study Design: Retrospective. Objective: Severe curves >100 degrees in adolescent idiopathic scoliosis (AIS) are rare and require careful operative planning. The aim of this study was to assess baseline, perioperative, and 2-year differences between anterior release with posterior instrumentation (AP), posterior instrumentation with posterior column osteotomies (P), and posterior instrumentation with 3-column vertebral osteotomies (VCR). Methods: Two scoliosis datasets were queried for primary cases of severe thoracic AIS (>= 100 degrees) with 2-year follow-up. Pre- and 2-year postoperative radiographic measures (2D and estimated 3D kyphosis), clinical measurements, and SRS-22 outcomes were compared between three approaches. Results: Sixty-one patients were included: 16 AP (26%), 38 P (62%), 7 VCR (11%). Average age was 14.4 +/- 2.0 years; 75.4% were female. Preoperative thoracic curve magnitude (AP: 112 degrees, P: 115 degrees, VCR: 126 degrees, P = 0.09) and T5-T12 kyphosis (AP: 38 degrees, P: 59 degrees, VCR: 70 degrees, P = 0.057) were similar between groups. Estimated 3D kyphosis was less in AP vs P (-12 degrees vs 4 degrees, P = 0.016). Main thoracic curves corrected to 36 degrees in AP vs 49 degrees and 48 degrees for P and VCR, respectively (P = 0.02). Change in estimated 3D kyphosis was greater in AP vs P and VCR (34 degrees vs 13 degrees, P = 0.009; 34 degrees vs 7 degrees, P = 0.046). One incomplete spinal cord injury had residual deficits (P; 1/61, 1.6%). All SRS-22 domains improved postoperatively. Conclusion: All approaches obtained satisfactory coronal and sagittal correction, but AP had smaller residual coronal deformity and greater kyphosis restoration than the other approaches. This information may help inform the decision of whether to include an anterior release for large thoracic AIS curves.