AB152. Two stage anterior-posterior fusion for double major adolescent idiopathic scoliosis (AIS): saving lumbar levels with improved derotation of the lowest instrumented vertebra
Session 11: Orthopaedic Session II

AB152. Two stage anterior-posterior fusion for double major adolescent idiopathic scoliosis (AIS): saving lumbar levels with improved derotation of the lowest instrumented vertebra

Jake Michael McDonnell1, Darren Liu2, Daniel Patrick Ahern3, Haiming Yu2, Adam Benton2, Anna Berridge2, Alexander Gibson2, Joseph Butler4, Sean Molloy2

1Department of Trauma & Orthopaedic Surgery, Royal College of Surgeons Ireland, Dublin, Ireland; 2Spinal Deformity Unit, Royal National Orthopaedic Hospital, Stanmore, UK; 3School of Medicine, Trinity College, Dublin, Ireland; 4Department of Trauma & Orthopaedic Surgery, National Spinal Injuries Unit, Mater Misericordiae University Hospital, Dublin, Ireland


Background: There is no consensus on the correction of adolescent idiopathic scoliosis (AIS) double major curves. Posterior only fusion may require extensive distal fusion or additional instrumentation, subsequently leading to a variety of complications. Alternatively, an anterior-posterior fusion (APF) is a powerful technique which can save lumbar motion segments while restoring lumbar apical rotation and tilt effectively.

Methods: A retrospective review was performed at our institution (RNOH) for patients undergoing AIS correction. Two thousand three hundred and fourteen cases from 2006 to 2012 (minimum 2-year follow-up) were identified. Preoperative demographics and mean values of: Standing radiograph Cobb, Harrington Stable Zone, Supine Bending Radiograph Cobb and Postoperative mean values: Correction Rate, Supine Bend Flexibility and Supine Bending Flexibility Index, LIV Tilt and Rotation Perdriolle Grade.

Results: Fifty-eight of 2,314 consecutive AIS cases were managed with a two stage anterior-posterior strategy. Comparison of pre- and post-operative radiographic parameters proved significant for cobb angle (MT: 62.7, 19.5; TL: 59.1,12.6; P<0.001), thoracic kyphosis (26.36°, 8.59°; P<0.001), lumbar lordosis (59.57°, 50.66°; P<0.001), LIV-ground angle (21.9°, 4.5°; P<0.001), and reduction in Perdriolle grade (1.7, 1.1; P<0.001). On average, the two-stage APF approach saved 1.58 motion segments compared to the HSZ method.

Conclusions: This technique achieved a high postoperative correction rate and supine bend correction index despite differing levels of stiffness, and an LIV of L3 or above was achieved in 90% of cases. The two stage APF surgical strategy attains desirable correction of coronal, sagittal, and rotational alignment in addition to saving lumbar motion segments compared to other methods.

Keywords: Adolescent idiopathic scoliosis (AIS); spinal deformity; spine surgery


doi: 10.21037/map.2020.AB152
Cite this abstract as: McDonnell JM, Liu D, Ahern DP, Yu H, Benton A, Berridge A, Gibson A, Butler J, Molloy S. Two stage anterior-posterior fusion for double major adolescent idiopathic scoliosis (AIS): saving lumbar levels with improved derotation of the lowest instrumented vertebra. Mesentery Peritoneum 2020;4:AB152.