SURGICAL TREATMENT OF DOUBLE MAJOR SCOLIOSIS (LENKE IIIC AND VIC) WITH STAGED ANTERIOR INSTRUMENTED THORACO-LUMBAR FUSION AND POSTERIOR INSTRUMENTED FUSION, WITH 5 YEAR FOLLOW-UP.

Abstract

Summary: Radiographic and clinical outcomes of anterior thoraco-lumbar and posterior instrumented spinal fusion in patients with double major (AIS) curves are evaluated in this retrospective study. The average thoracic curve was 68 degrees before surgery and 29.2 degrees at follow-up (mean correction 58.3%). The average preoperative lumbar curve was 73 degrees, decreasing to 18 degrees postoperatively (mean correction 77.5%). Instrumented anterior lumbar fusion followed by posterior instrumented fusion is a successful technique with low morbidity in AIS with double curve pattern.

Introduction: Options exist for the surgical treatment of double major AIS curves. With the introduction of multi-level pedicle screw fixation in the thoracic and lumbar spines the role of anterior surgery is being questioned. This series demonstrates the results obtained by anterior thoraco-lumbar and posterior instrumented spinal fusion.

Methods: 28 patients with double major curves who underwent anterior spinal release and instrumented fusion, with staged posterior instrumented spinal fusion between 1999 and 2005 were included for analysis. The minimum follow-up was 2 years after surgery (mean, 5 years; range, 2–8 years). The mean age of patients was 17,3 years (range, 13–21 years). Multiple radiographic parameters were assessed.

Results: Successful selective thoraco-lumbar instrumented fusion and posterior instrumented fusion was performed in 28 consecutive patients with adolescent idiopathic scoliosis. The average thoracic curve was 68 degrees before surgery and 29,2 degrees at final follow-up (mean correction 58,3%). The average pre-operative lumbar curve was 73 degrees, decreasing to 18 degrees postoperatively (mean correction 77,5%), with good coronal and sagittal balance achieved. Tilt of the lower instrumented vertebra (LIV) improved from 28.2 degrees to 4.6 degrees on last follow-up. Disc angulation below the LIV averaged 6.1 degrees preoperatively and 3.6 degrees on last follow-up. Translation of the LIV from the center sacral vertical line averaged 34.5 mm preoperatively and 13.6 mm on last follow-up.

Discussion: Instrumented anterior lumbar fusion followed by posterior instrumented fusion is a successful technique in adolescent idiopathic scoliosis with double curve pattern. These results show that this technique is able to restore normal coronal alignment of the distal unfused lumbar segment and saves fusion levels compared to posterior instrumentation only. Despite the extensive surgery, there is a very low morbidity in this population, with no evidence of pseudarthrosis.

Significance: This represents a large unique series of patients treated for double major curve pattern in adolescent idiopathic scoliosis with low morbidity and excellent balanced corrections in both coronal and sagital planes.